Ericsson MINI-LINK E, MINI-LINK E Micro Technical Description

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MINI-LINK E and E Micro

Technical Description

MINI-LINK

™

MINI-LINKEandEMicro

Technical Description

© Ericsson Microwave Systems AB. All rights reserved. No parts of this publication may be reproduced, stored in a retrieval system, or t ransmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission of the publisher.

Disclaimer

The contents of this document are subject to revision without notice due to continued progress in methodology, design, and manufacturing. Er icsson shall have no liability for any error or damage of any kind resulting from the use of this document.

If there is any conflict between this document and compliance statements, the latter will supersede this document

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Conte

1 Introduction 1

1.1 General 1

1.2 Applications 2

1.3 Main Features 5

1.4 Related Documents 6

2 Product Program 7

2.1 Introduction 7

2.2 MINI-LINK E 8

2.3 MINI-LINK E M icro 18

2.4 Network Management 20

3MINI-LINKE 23

3.1 General 23

3.2 Radio Units 23

nts

3.3 RAU1 (7-E and 8-E) 25

3.4 RAU1 (15-E, 18-E, 23-E, 26-E and 38-E) 30

3.5 RAU2 35

3.6 Access Module 40

3.7 AMM – Access Module Magazine 41

3.8 MMU – Modem Unit 43

3.9 SMU – Switch Multiplexer Unit 53

3.10 SAU – Service Access Unit 63

3.11 ETU – Ether net Interface Unit 69

3.12 Traffic Routing 74

3.13 Upgrading 77

4 MINI-LINK E Micro 79

4.1 General 79

4.2 RTU – Radio Unit 79

4.3 Block Diagram 82

4.4 Modem Board 82

4.5 Microwave Unit 86

4.6 Filter Unit 88

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5 Antennas 89

5.1 Antenna Description 89

5.2 Antenna Installation 90

6 Management System 93

6.1 Operation and Maintenance Facilities 93

6.2 MSM – MINI-LINK Service Manager 110

6.3 MINI-LINK Netman 111

7 Accessories 113

7.1 RCB – Radio Connection Box 113

7.2 MXU – MINI-LINK Cross-connect Unit 115

7.3 DDU – DC Distribution Unit 120

7.4 PSU – AC/DC Power Supply Unit 122

7.5 Terminal Server 124

8 Technical Data 125

8.1 System Parameters 125

8.2 Antenna Data 135

8.3 Environmental Requirements 139

8.4 Power Supply 140

8.5 Cables 143

8.6 Interfaces 147

8.7 ETU Data 152

8.8 MXU Data 152

8.9 Fan Unit Data 154

8.10 DDU Data 154

8.11 PSU Data 154

8.12 Mechanical Data 156

8.13 Management System Data 171

Glossary 175

Index 179

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1 Introduction

1.1 General

MINI-LINK E and MINI-LINK E Micro are product families for medium capacity point-to-point microwave transmission. The purpose of this description is to support the reader with detailed information on included products with accessories, from technical and functional points of view.

For ordering information, please refer to the latest revision of the MINI-LINK E and E Micro P roduct Catalog (AE/LZT 110 2011).

You m ay also contact your Ericsson representative or the business manager for your country at:

MINI-LINKEandEMicro

Ericsson Microwave Systems AB Transmission & Transport Networks SE-431 84 Mölndal, SWED EN Telephone: +46 31 747 00 00 Fax: +4631277225

1.1.1 Revision Information

This revision of the MINI-LINK E and E Micro Technical Description includes the introduction of the following:

• Ethernet Interface Unit (ETU)

• RAU2 for 28 GHz

• 1.8 m compact antennas

• Terminal server

Most of the technical description of MINI-LINK Netman in Section 6.3 on page 111 has been transferred to Netman Technical Description (AE/LZT 110 5048).

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1.2 Applications

MINI-LINK is a member of Ericsson’s large and extensive product portfolio for telecommunications. The combined expertise of Ericsson, covering switching, cellular technology, radio and network ing, provides excellent turnkey project management. MINI-LINK integrates fully with existing telecom networks, adding new levels of flexibility. It has proved to be a reliable communication medium, a highly competitive alternative to copper and fiber cable.

MINI-LINK E and E Micro provides point-to-point microwave transmission from 2 up to 34+2 (17x2) Mbit/s, operating within the 7 to 38 GHz frequency bands. They are briefly described as follows:

• MINI-LINK E comprises an indoor access module and an outdoor radio unit with antenna. It offers flexibility and capacity at small sites as well as large multi-terminal sites. Terminals can be configured for different network types: star, tree or ring. For protection, they can be configured either as a 1+1 system or as a ring structure.

• MINI-LINK E Micro is a compact all-outdoor term inal providing minimal total site cost, typically used at end sites together with other all-outdoor equipment.

A mobile transmission network is by far the most common application of MINI-LINK E and E Micro, where they are deployed in the Low Capacity Radio Access Network ( LRAN).

MSC - Mobile Switching Center

MG - Media Gateway

BSC - Base Station Controller

RNC - Radio Node Controller

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Switch site

Transmission hub site

MSC/ MG

HUB

BSC/ RNC

HUB

MSC/ MG

HUB

Core Network

High Capacity Radio Access Network (HRAN)

Low Capacity Radio Access Network (LRAN)

Figure 1 A mobile transmission network

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MINI-LINK

Base station

MSC

BSC

Figure 2 Example of a mobile network, where MINI-LINK products connect radio base stations to switching centers

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The figure below shows an example of how MINI-LINK E and E Micro can be used in different network topologies.

Star

Ring

Tree

MINI-LINK E MINI-LINK E Micro

Figure 3 Example of network topologies

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The following figures show applications in a pr ivate and fixed network.

PBX

Public

network

PBX

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Figure 4 Example of a private network, where MINI-LINK products connect major sites

RSS

AXE

RSS

RSM

RSS

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Figure 5 Example of a fixed network using AXE systems, where remote subscriber access units are connected to the network with MINI-LINK products

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1.3 Main Features

Technical features

• Extremely compact and integrated design

• The radio and antenna form an integrated outdoor part

• High system gain and spectrum utilization with an advanced m odulation process and coding

• 2 to 17x2 (34+2) Mbit/s traffic capacity

• Software tool for easy installation

• Advanced element manager

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• Standardized interfaces

• Low weight and power consumption

Reliability

• High Mean Time Between Failure ( MTBF)

• Progress with backward compatibility

• Part of the Ericsson system portfolio

• 30 years’ experience of microwave transmission

• World’s largest production of microwave transmission systems

• MINI-LINK equipment can cope with extreme environments

Services

• Ericsson turnkey capability

• Customer training programs worldwide

• Total field maintenance services

• Ericsson local presence in more than 140 countries

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1.4 Related Documents

This section gives an overview of some MINI-LINK E and E Micro related documents. The documents can be ordered separately and can also be downloaded from the Ericsson Intranet and customer Extranet portals.

MINI-LINK E and E Micro Product Catalog (AE/LZT 110 2011)

The product catalog is intended to be an aid when compiling an order or just to give a more detailed overview of the products in the MINI-LINK E and E Micro product families.

Netman Technical Description (AE/LZT 110 5048)

The document describes the technical features of the element management system Netman.

MINI-LINK E and E Micro Planning and Engineering Manual (EN/LZT 110

2013)

The manual is used for planning and engineering of a MINI-LINK E and E Micro network.

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2 Product Program

2.1 Introduction

A terminal is one side of a microwave radio link hop, between two geographical locations. The networks of today contain both single terminal sites and more complex multi-terminal sites. MINI-LINK E and E Micro feature these types of terminal configurations, further described in this chapter.

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MINI-LINK E

Antenna

Radio

unit

Access module

To operator

equipment

Radio

unit

operator equipment

Figure 6 Two examples of terminal configuration

MINI-LINK E Micro

Antenna

To all-outdoor

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2.2 MINI-LINK E

Several M INI-LINK E terminals can be integrated into one common access module. This enables extremely compact network sites as well as efficient sharing of resources between different terminals, such as multiplexers, service channel interfaces and support systems.

Traffic routing and re-routing within a network site can be performed with a minimum of external cables. Traffic routing is software configured during station setup.

Terminals can be configured for unprotected (1+0), protected (1+1) terminals or ring protection.

Each terminal provides traffic capacity for up to 17x2 (34+2) Mbit/s.

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Figure 7 A MINI-LINK E multi-terminal site

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2.2.1 System Components

Figure 8 The main parts of a MINI-LINK E terminal

Radio

unit

Access module

To operator

equipment

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Antenna

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A MINI-LINK E terminal consists of an outdoor and indoor part. There are also a number of well-adapted accessories, both hardware and software.

Outdoor Part

The outdoor part is fully independent of traffic capacity and supplied for various frequency bands.

It consists of an antenna module, a Radio Unit (RAU) and associated installation hardware. The antenna and the radio unit are either integrated or installed separately. For protected systems (1+1), two radio units and one or two antennas are used.

Indoor Part

The indoor part, the access module, is fully independent of frequency band and supplied in different versions for various traffic capacities and system configurations. It can support up to four radios.

It consists of a Modem Unit (MMU) and an optional Switch Multiplexer Unit (SMU), as well as an optional Service Access Unit (SAU), all housed in one common Access Module Magazine (AMM). For protected systems, two MMUs and one SMU are used.

The indoor part is connected to the outdoor part with a single coaxial cable (the radio cable).

For Ethernet traffic the optional ETU can be used, see Section 3.11 on page 69.

For ring protection the optional MINI-LINK Cross-connect Unit (MXU) can be used, see Section 7.2 on page 115.

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Access module

(SAU)

MMU MMU

SMU SMU MMU MMU

Radio unit

Antenna

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Figure 9 A multi-terminal site

2.2.2 Outdoor Installation

The radio unit and the antenna are easily installed on a wide range of support structures.

The radio unit is fitted directly to the antenna as standard, integrated installation. The radio unit and the antenna can also be fitted separately and connected by a flexible waveguide.

In both cases, the antenna is easily aligned and the radio unit can be disconnected and replaced without affecting the antenna alignment.

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Figure 10 The radio unit fitted directly to a 0.2 m compact antenna and a

0.6 m compact antenna respectively

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Figure 11 The radio unit and a 0.6 m compact antenna fitted separately

2.2.3 Indoor Installation

The indoor parts are fitted in 19" racks, in ETSI and BYB cabinets or directly on the wall/desk. An access module consists of an Access Module M agazine (AMM) and a set of different plug-in units. The following AMMs for different applications are available as standard:

• AMM 1U for end terminals

• AMM 2U-3 for single or dual terminal sites, containing up to four plug-in units

• AMM 4U for more complex, multi-terminal sites, containing up to seven plug-in units

The indoor part can be upgraded or reconfigured with plug-in units, providing site flexibility.

The interconnection between the outdoor part (radio unit and antenna) and the indoor part is a single coaxial cable carr ying full duplex traffic, DC supply voltage, service traffic as well as operation and maintenance data.

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Figure 12 The AMM 2U-3 for a maximum of four units

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Figure 13 The AMM 4U for a maximum of seven units

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2.2.4 Configurations

2.2.4.1 Unprotected Terminal (1+0)

As a minimum a 1+0 terminal consists of:

•RAU

• Antenna

•AMM1U

• MMU

• Coaxial cable for interconnection

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For traffic capacities 8x2, 17x2 and 4x8+2, an SMU is required. An SAU can be added to the AMM to provide additional alarm and control interfaces, service channels and other customer specific applications.

AMM 1U

MMU

2x2, 4x2, 8, 2x8 or 34+2 Mbit/s

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Figure 14 1+0 configuration. The MMU can be installed in an AMM 1U (AMM 2U-3 if SAU is required).

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Figure 15 1+0 configuration for 8x2, 4x8+2 and 17x2 Mbit/s capacities

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2.2.4.2 Protected Terminal (1+1)

As a minimum, a 1+1 terminal consists of:

• Two RAUs

• Two antennas or one antenna with a power splitter

• One AMM 2U-3 (or AMM 4U) with two MMUs and one SMU

• Two coaxial cables for interconnection

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Figure 16 1+1 configuration requires an AMM 2U-3 (AMM 4U can be used as an alternative)

An SAU can also be added to the AMM to provide additional alarm and control interfaces, ser vice channels and other customer specific applications.

The radio units can be equipped with individual antennas or connected to a common antenna. In the case of one common antenna, the two radio units are connected by waveguides to a power splitter, fitted on a single-polarized antenna.

Automatic switching can be in hot standby or in working standby (frequency diversity). Receiver switching in space diversity systems is hitless.

In hot standby mode, one transmitter is working while the other one is in standby (that is, not transmitting but ready to transmit if the active transmitter malfunctions). Both radio units are receiving signals. The MMU selects the best signal according to an alarm priority list, connects it first to the SMU for demultiplexing and then to external equipment. See Section 3.9.2.6 on page 58 for fur ther information about switching.

In working standby mode, both radio paths are active in parallel using different frequencies.

The 1+1 configuration should be considered for important and/or heavy traffic requiring high availability, but also if there are severe reflections and/or harsh atmospheric conditions.

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2.2.4.3 Configurations at Multi-terminal Sites

Several terminals can be integrated in the same indoor AMM. Different configurations, traffic capacities and radio frequencies can be combined. A site can be upgraded easily by substituting and/or adding plug-in units.

• One AMM 2U-3 c an hold:

− Two unprotected (1+0) terminals or one protected (1+1) terminal

− One SAU

• One AMM 4U can hold:

− Up to four unprotected (1+0) terminals

− Two protected (1+1) terminals

− One protected (1+1) terminal plus one or t wo unprotected (1+0)

terminals

− One SAU

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Software controlled traffic routing between the terminals minimizes site cabling, see S ection 3.12 on page 74.

One SMU can contain multiplexers/demultiplexers for two terminals. The terminals can also share the same optional SAU. The SAU offers analog or digital service channels as well as parallel inputs/outputs for integration of alarms and external equipment control.

Figure 17 A multi-terminal site with drop of 7x2 Mbit/s

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2.2.4.4 Repeater Site (1+0 or 1+1)

The repeater site basically comprises two terminals, back-to-back. The two radio units are connected by using two MMUs in the same access module without any external cables.

Figure 18 A 1+0 repeater site

Drop/Insert

If one or more traffic signals are to be dropped and/or inserted at the repeater site, this can be accomplished either directly at the MMUs, provided that M MUs with 2 Mbit/s interfaces are selected or by including an SMU on the site.

An SAU can be added to the AMM to provide additional alarm and control interfaces, ser vice channels and other customer specific applications.

2.2.4.5 Ring Protection

An MX U added to the AMM enables ring protection. For further information, see Section 7.2 on page 115.

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2.2.4.6 Ethernet Traffic

An ETU added to the AMM enables transmission of Ethernet traffic. The typical application of the ETU is LAN-to-LAN interconnection using the following site configuration:

•RAU

• Antenna

•AMM2U-3

•ETU

• MMU

• Coaxial cable for interconnection

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AMM 2U-3

10BASE-T/100BASE-TX

n x E1/E2

ETU

MMU

5505

Figure 19 Typical site configuration using ETU for LAN-to-LAN interconnection with optional PDH traffic connected to the MMU

The ETU can also be used in a protected (1+1) terminal configuration or in multi-terminal configurations.

For more information on the ETU, see Section 3.11 on page 69.

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2.3 MINI-LINK E Micro

MINI-LINK E Micro is a ver y small and easily installed all-outdoor radio, housing all transmission components. It can be used at all-outdoor sites with up to three unprotected (1+0) connections and provides traffic capacity for up to 2x2 Mbits.

The traffic interface has long-haul capabilities, allowing a cable length that enables flexible installation of the terminal.

A terminal consists of an outdoor radio unit (RTU), an antenna and an optional Radio Connection Box (RCB).

For more information on MINI-LINK E Micro, see Section 4 on page 79.

Figure 20 M INI-LINK E Micro with a 0.2 m compact antenna

2.3.1 Configurations

Figure 21 A MINI-LINK E Micro terminal with traffic and DC cables

MINI-LINK E Micro has standardized t raffic interfaces for 2 or 2x2 Mbit/s (only 2x2 Mbit/s for the 38 GHz version).

Traffic

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The terminal can be DC or AC powered. On sites with only one terminal, traffic and DC can be directly connected with two cables. On sites with more than one terminal or where no DC supply is available, a Radio Connection Box (RCB) is required. For more information, see Section 7.1 on page 113.

The gray painted radio unit fits onto the back of the antenna, but can equally well be installed separately from the antenna and connected with a waveguide feeder.

Applications for MINI-LINK E Micro are in mobile telephony, business access, PBX (Private Branch eXchange), and data networks together with any outdoor installed telecom equipment.

It can be used as an end-terminal or when using the RCB as a repeater or multi-terminal site.

Figure 22 MINI-LINK E M icro with RCB, multi-terminal site

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2.4 Network Management

The maintenance features enable flexible and easy setup and facilitate faultfinding and repair. N etwork management features are:

• Alarm transfer channel

• Performance monitoring

• Near and far-end loop-back tests

• Data and voice service channels

• Software controlled routing of traffic

• Software selectable output power and frequency

• Remote software upgrade

• Capacity agile MMU configuration

PSTN back-up

or other line

Leased line or

other fixed channel

Radio Unit/ Antenna Module

Access Module

Operation & maintenance

centre

3509

Figure 23 MINI-LINK network management

A microprocessor monitors all functional alarms and transmits them on an Operation & Maintenance channel, which extends throughout the sub-network. MINI-LINK Netman can be used for central supervision of the equipment in a network.

Easy Access at Any Location

The service engineer can access the Operation & Maintenance channel for functional alarms at any location. He thus gets an overview of t he network status by using a PC with the MINI-LINK Service Manager (MSM) software. The service engineer can also reconfigure the traffic routing, check performance data or switch between operating and standby equipment. He

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can also command near-end and far-end loop-backs to be performed. Local configuration of the capacity agile MMU at the near-end can be carried out as well.

Local Management

The local supervision interface on the MMU enables fault finding and measurement when a PC is not available.

Service Channel

The integrated maintenance system is optionally supplemented with two service channels. These service channels may be configured as digital data channels (64 kbit/s) or as omnibus voice channels with a built-in telephone interface.

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3MINI-LINKE

3.1 General

MINI-LINK E comprises an indoor access module, an outdoor radio unit with antenna and mounting kit. The radio unit is connected to the indoor unit with a single coaxial cable and can be combined with a wide range of antennas for integrated or separate installation.

Radio

unit

MINI-LINKEandEMicro

Antenna

Figure 24 MINI-LINK E terminal

3.2 Radio Units

The radio units are continuously developed and improved regarding design and technology. Two types of radio unit are available, RAU1 and RAU2. They have the same functionality, but different mechanical design and microwave technology. RAU2 has a higher integration of microwave circuits.

The radio units are independent of traffic capacity, that is the operating frequency is determined by the radio unit only. The operating frequency is set on site. This is done with the management software products or with a toggle switch on the indoor MMU.

The radio unit is a weatherproof box painted light gray, with a handle for lifting and hoisting. It connects to the antenna unit at the waveguide port. The radio unit also has two hooks and catches to guide it for easier handling, when fitting to or removing from an integrated antenna.

Access module

To operator

equipment

3520

Radio units are available for different frequency channel arrangements according to ITU-R and ETSI recommendations. For detailed information on frequency versions, see Section 8 on page 125 and the MINI-LINK E and E Micro Product Catalog (AE/LZT 110 2011).

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Figure 25 The RAU1 and RAU2 radio units

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3.3 RAU1 (7-E and 8-E)

This radio unit contains frame, cover, microwave sub-unit and filter unit.

The vertical frame has a waveguide interface for connection to the antenna.

The bottom of the cover carr ies the radio cable connector that is the interface with the indoor modem unit (MMU), and a test port for antenna alignment. The connector for the radio cable is equipped with gas discharge tubes for lightning protection.

Replacing the filter unit can change the sub-band for a radio within a group of sub-bands. For more information, see the MINI-LINK E and E Micro Product Catalog (AE/LZT 110 2011), chapter Radio Units.

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Figure 26 RAU1 for 7 and 8 GHz

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3.3.1 Block Diagram

MMU

Microwave Sub-unit

Transmit IF

Signal,

350 MHz

Receive IF

Signal,

140 MHz

Cable Interface

Command

& Control

Signal

Transmit IF

Signal

Processing

Receive IF

Signal

Processing

Control &

Supervision

Processor

Transmitter

To Alignment Port

DC/DC Converter

Converter

Transmitter

Oscillator

FREQUENCY CONTROL

Receiver

Amplifier

Down

Converter

Filter

Amplifier

Output

Level

Control

FREQUENCY CONTROL

Receiver

Oscillator

Low

Noise

Amplifier

Alarm

and

Control

Final

TX OFF

OUTPUT LEVEL SET

Secondary

Voltages

Power

Detector

RF Loop

RF Attenuator

(accessory)

Filter Unit

Branching

Filter

Antenna

Branching

Filter

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Figure 27 RAU1 7-E and 8-E block diagram

3.3.2 Microwave Sub-unit

The following functions are in

• DC/DC Converter

• Cable interface

• Control and supervision

• Transmit signal processing

• Receive signal processing

The microwave sub-unit consists of a microstrip board with an aluminum cover that provides shielded compartments for the high-frequency circuits. The control circuit board is fitted t o the back of the microstrip board.

The microwave sub-unit is fully independent of transmission rates.

A microwave sub-unit covers several sub-bands. The sub-band is defined by the microwave sub-unit together with the filter unit.

cluded in the microwave sub-unit:

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3.3.2.1 DC/DC Converter

The DC/DC converter provides stable voltages for the microwave sub-unit.

3.3.2.2 Cable Interface

The incoming composite signals from the indoor units, that is, transmitting IF signal, command and control signal and DC, are demultiplexed in the cable interface and forwarded for further processing.

• The transmitting IF signal is a modulated signal with a nominal frequency of 350 MHz.

• The command and control signal up-link is an ASK (Amplitude Shift Keying) modulated signal with a nominal frequency of 6.5 MHz.

MINI-LINKEandEMicro

• The DC feed is in the range of 45 – 60 V DC (24 – 60 V DC, nominal, is connected to the MMU).

Similarly, the outgoing signals are multiplexed in the cable interface: receiving IF signal and command and control signal down-link.

• The nominal frequency of the receiving IF signal is 140 MH z.

• The command and control signal down-link is an ASK modulated signal with a nominal frequency of 4.5 MHz.

In addition to the above, the cable interface includes an overvoltage protection circuit.

3.3.2.3 Control and Supervision Processor

The microwave sub-unit houses the processor for control and supervision of the radio unit. The main functions of this processor are described below.

Alarm Collection

Collected alarms and status signals from the radio unit are sent to the indoor MMU processor. Sum mary status signals are visualized by LEDs on the radio unit.

Command Handling

Commands from the indoor units are executed. These commands include transmitter activation/deactivation, channel frequency settings, output power settings and RF loop activation/deactivation.

Radio Unit Control

The processor also controls the radio unit’s internal processes and loops.

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3.3.2.4 Transmit IF Signal Processing

The input amplifier is automatically gain-controlled so that no compensation is required due to the cable length between indoor and outdoor equipment.

The level is used to generate an alarm, indicating that the transmitting IF signal level is too low due to excessive cable losses.

3.3.2.5 Transmitter Block

Upconverter

The transmitting IF signal is amplified and up-converted to 7 GHz / 8 GHz in the transmitter.

Transmitter Oscillator

The frequency of the transmitter is controlled in a Phase Locked Loop (PLL) (a sample of the VCO signal is fed to a divider and further on to a programmable phase detector). The error signal is controlled by the integrated control and supervision system by using a serial bus. An unlocked VC O loop generates a transmitter frequency alarm.

Final Amplifier

The transmitter output power is controlled by adjusting the gain of the final amplifier. The output power is set in steps of 1 dB through the operation and maintenance system. The transmitter can be switched on or off by switching the final amplifier.

3.3.2.6 Power Detector

A sample of the transmission signal is used for supervision of the transmitted power (output power alarm).

3.3.2.7 RF Loop

A sample of the transmission signal is mixed with a shift oscillator signal and is fed into the receiver for test purposes.

3.3.2.8 RF Attenuation

In addition to the transmitter output power control described above, the output RF level may be further decreased by fitting fixed RF attenuators to the microwave unit. The transmitted RF can then be attenuated by a total of 50 dB. See Section 8.1.1 on page 126 for more details.

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3.3.2.9 Receiver Block

The received signal is fed from the input branching filter into a low noise amplifier and down-converted to 140 MHz.

Receiver Oscillator and Filter

An LO signal for the down-conversion is generated in the same way as for the transmitted signal. A frequency error signal from the MMU is used to shift the receiver VCO in order to facilitate an AFC-loop.

3.3.2.10 Receive IF Signal Processing

The 140 MHz receiving IF signal from the receiver is amplified and fed to the cable interface. Additionally, a portion of the signal is fed to a calibrated detector to provide an accurate receiver input level measurement. The measured level is accessible either as an analog voltage at the alignment port or in dBm through the operation and maintenance system.

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3.3.3 Filter Unit

Branching Filter

On the transmitting side, the signal is fed to the antenna through an output branching filter. The signal from the antenna is fed to the receiving side through an input branching filter. The antenna and both branching filters are connected with an impedance T-junction.

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3.4 RAU1 (15-E, 18-E, 2 3-E, 26-E and 38-E)

This radio unit contains cover, frame, a radio interface sub-unit and a microwave sub-unit.

The radio interface sub-unit consists of a circuit board assembly, including external interfaces with the indoor units. This interface is a 50 connector. A connector for RF input level measurements and a set of LEDs are accessible from the outside of the radio unit. The microwave sub-unit consists of a microstrip board w ith an aluminum cover that provides shielded compartments for the high-frequency circuits. The control circuit board is fitted at the back of the microstrip board. The microwave sub-unit provides a waveguide interface with the antenna.

The DC/DC converter is fitted directly on the vertical frame and connected to the m icrowave sub-unit by a flat cable.

N-type

The vertical frame also has a waveguide port for connection to the antenna.

The bottom of the cover carries the radio cable connector, which is the interface with the indoor modem unit (MMU), and a test port for antenna alignment. The connector for the radio cable is equipped with gas discharge tubes for lightning protection.

3555

Figure 28 RAU1 15-E, 18-E, 23-E, 26-E and 38-E

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3.4.1 Block Diagram

MINI-LINKEandEMicro

Radio Interface Sub-unit

MMU

Transmit IF

Signal,

350 MHz

Receive IF

Signal,

140 MHz

Cable Interface

Command

& Control Signal

Transmit IF

Signal

Processing

Receive IF

Signal

Processing

Control & Supervision Processor

To Alig nment Port

Microwave Sub-unit

FREQUENCY CONTROL

Receiver

FREQUENCY CONTROL

AFC

Receiver

Oscillator

Converter

Transmitter

Oscillator

Down

Alarm and Control

Multiplier

Filter &

Amplifier

First IF around 1000 MHz

DC/DC Converter

& Filter

Multiplier

and

Filtering

Down

Converter

Final

Amplifier

Output

Level

Control

15, 23 and 26 high power

OUTPUT LEVEL SET

Low

Noise

Amplifier

Not 38 GHz

Secondary voltages

TX OFF

Power

Detector

RF Loop

15,18 and 23 GHz

Branching

Filter

RF Attenuator

(accessory)

Branching

Filter

Antenna

3537

Figure 29 RAU1 15-E, 18-E, 23-E, 26-E and 38-E block diagr

3.4.2 Radio Interface Sub-unit

The following functions are included in the radio interface sub-unit:

• Cable interface

• Control and supervision

• Transmit IF signal processing

• Receive IF signal processing

3.4.2.1 Cable Interface

• The transmitting IF signal is a modulated signal with a nominal frequency of 350 MHz

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MINI-LINKEandEMicro

• The command and control signal up-link is an ASK (Amplitude Shift Keying)

• The DC feed is in the range of 45 – 60 V DC (24 – 60 V DC, nominal,

Similarly, the outgoing signals are multiplexed in the cable interface: receiving IF signal and comm and and control signal down-link.

• The nominal frequency of t he receiving IF signal is 140 MHz.

• The comm and and control signal down-link is an ASK modulated signal

In addition to the above, the cable interface includes an overvoltage protection circuit.

modulated signal with a nominal frequency of 6.5 MHz.

is connected to the MMU)

with a nominal frequency of 4.5 MHz.

3.4.2.2 Control and Supervision Processor

The radio interface sub-unit houses the processor for control and supervision of the radio unit. The main functions of this processor are described below.

Alarm Collection

Collected alarms and status signals from the radio unit are sent to the indoor MMU processor. Summary status signals are visualized by LEDs on the radio unit.

Command Handling

Commands from the indoor units are executed. These commands include transmitter activation/deactivation, channel frequency settings, output power settings and RF loop activation/deactivation.

Radio Unit Control

In addition to the above, the processor controls the radio unit’s internal processes and loops.

3.4.2.3 Transmit IF Signal Processing

The transmit IF signal is amplified, limited and demodulated. The dem odulated signal is amplified and passed through a buffer amplifier to the microwave sub-unit for modulation onto the RF carr ier.

The input amplifier is automatically gain-controlled so that no compensation is required due to the cable length between indoor and outdoor equipment.

The level is used to generate an alarm, indicating that the transmitting IF signal level is too low due to excessive cable losses.

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3.4.2.4 Receive IF Signal Processing

The 140 MHz receive IF signal from the microwave sub-unit is amplified and fed to the cable interface. Additionally, a portion of the signal is fed to a calibrated detector to provide an accurate receiver input level measurement. The measured level is accessible either as an analog voltage (AGC) at alignment port or in dBm through the operation and maintenance system.

3.4.3 Microwave Sub-unit

3.4.3.1 DC/DC Converter

The DC/DC converter provides stable voltages for the microwave sub-unit as well as for the radio interface unit.

MINI-LINKEandEMicro

3.4.3.2 Transmitter Block

Transmitter Oscillator

The frequency of the transmitter is controlled in a phase locked loop (PLL) (a sample of the VCO signal is fed to a divider and further on to a programmable phase detector). The error signal is controlled by the integrated control and supervision system by using a serial bus. An unlocked VCO loop generates a transmitter frequency alarm.

Multiplying and Filtering

The VCO signal is amplified, frequency multiplied and filtered.

Final Amplifier

The transmitter output power is controlled by adjusting the gain of the final amplifier. The output power is set in steps of 1 dB through the operation and maintenance system (Note: This applies to RAU1 15-E, 18-E, 23-E and 26-E HP. RAU1 26-E and 38-E have a mechanical, adjustable attenuator adjacent to the branching filter). The transmitter can be switched on or off by switching the final amplifier.

Branching Filter

On the transmitting side, the signal is fed to the antenna through a branching filter and a circulator. On the receiving side, the circulator feeds the received signal to an input branching filter.

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Power Detector

A sample of the transmission signal is used for supervision of the transmitted power (output power alarm).

3.4.3.3 RF Loop (Only RAU1 15-E, 18-E and 23-E)

A sample of the transmission signal is mixed with a shift oscillator signal and is fed into the receiver for test purposes.

3.4.3.4 RF Attenuation

3.4.3.5 Receiver Block

The received signal is fed from the input branching filter into a low noise amplifier (with the exception of RAU1 38-E) and a down-converter to a first IF of approximately 1 GHz. After bandpass filtering and amplification, the signal is down-converted to the second IF of 140 MHz.

Receiver Oscillator, Multiplier and Filter

LO signals for the two down-conversions are generated in the same way as for the transmitted signal. A frequency control signal from the MMU (AFC) is fed to the receiver oscillator by the control and supervision processor.

This double superheterodyne receiver with a high first IF enables frequency selection over a wide frequency band, w ith excellent receiver spurious and image rejection.

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3.5 RAU2

This radio unit consists of cover, frame, connection unit, microwave unit and filter unit.

The connection unit forms the bottom of the radio unit cover and it holds alarm indicators (LEDs) and connectors for traffic, grounding, DC power and antenna alignment. The connection unit is also equipped with lightning protection.

The microwave unit is a circuit board assembly, consisting of a radio board and two MCMs (Multi-chip M odule) for the transmitting and receiving parts of the radio unit. The high-frequency MCM components are shielded with an aluminum cover. In addition, it contains the cable interface, the DC/DC converter, control and super vision functions and components for IF signal processing.

MINI-LINKEandEMicro

The cable interface with the indoor units is a 50

N-type connector. The filter unit consists of two branching filters and an impedance T-junction which is the interface with the antenna.

Cover

Frame

Filter unit

Microwave unit

Figure 30 RAU2 parts

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Earthing screw

Connection unit

3548

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3.5.1 Block Diagram

MMU

Microwave Unit

Transmit IF

Signal, 350 MHz

Receive IF

Signal,

140 MHz

Cable Interface

Command & Control

Signal

To Alignment Port

Transmit IF

Signal

Processing

DC/DC Converter

RSSI

Control & Supervision Processor

Alarm and Control

Secondary voltages

FREQUENCY

CONTROL IF

140 MHz

FREQUENCY CONTROL TX

Oscillator

834 MHz

Down

Converter

Transmitter ( MCM )

Transmitter

Oscillator

IF Converter

Filter & Amplifier

Multiplier

974 MHz

OUTPUT LEVEL SET

Receiver

Oscillator

Multiplier

Down Converter

Power

Amplifier

TX OFF

Output

Level

Control

Receiver ( MCM )

FREQUENCY CONTROL RX

Low Noise Amplifier

Loop

Filter Unit

Branching

Filter

Branching Filter

Antenna

3539

Figure 31 RAU2 block diagram

3.5.2 Microwave Unit

3.5.2.1 DC/DC Converter

The DC/DC converter provides stable voltages for the radio unit.

3.5.2.2 Cable Interface

• The transmitting IF signal is a modulated signal with a nominal frequency of 350 MHz

• The command and control signal up-link is an ASK (Amplitude Shift Keying) modulated signal with a nominal frequency of 6.5 MHz.

• The DC feed is in the range of 45 – 60 V DC (24 – 60 V DC, nominal, is connected to the MMU).

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Similarly, the outgoing signals are multiplexed in the cable interface: receiving IF signal and command and control signal down-link.

• The nominal frequency of the receiving IF signal is 140 MH z.

• The command and control signal down-link is an ASK modulated signal with a nominal frequency of 4.5 MHz.

In addition to the above, the cable interface includes an overvoltage protection circuit.

3.5.2.3 Control and Supervision Processor

The processor for radio unit control and supervision is situated on the microwave unit circuit board. Its main functions are described below.

MINI-LINKEandEMicro

Alarm Collection

Collected alarms and status signals from the radio unit are sent to the indoor MMU processor. Sum mary status signals are visualized by LEDs on the radio unit.

Command Handling

Commands from the indoor units are executed. These commands include transmitter activation/deactivation, channel frequency settings, output power settings and RF loop activation/deactivation.

Radio Unit Control and Message Handling

The processor also controls the radio unit’s internal processes and loops.

3.5.2.4 Transmit IF Signal Processing

The transmit IF signal is amplified, limited and demodulated. The demodulated signal is amplified and passed through a buffer amplifier to the transmitter MCM for modulation onto the RF carrier.

The level is used to generate an alarm, indicating that the transmit IF signal level is too low due to excessive cable losses.

The input amplifier is automatically gain-controlled so that no compensation is required due to the cable length between indoor and outdoor equipment.

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3.5.2.5 Transmitter Block

Transmitter Oscillator (MCM)

The frequency of the transmitter is controlled in a Phase Locked Loop (PLL) (a sample of the VCO signal is fed to a divider and further on to a programmable phase detector). An unlocked VCO loop generates a transmitter frequency alarm.

Multiplier (MCM)

The VCO signal is amplified and frequency multiplied (2 or 4 times depending on channel frequency).

Power Amplifier (MCM)

The transmitter output power is controlled by adjustment of the gain in the final amplifier. The output power is set in steps of 1 dB through the operation and maintenance system. The transmitter can be switched on or off by switching the final amplifier.

3.5.2.6 Output Level Control

The output signal level from the final amplifiers are analyzed in order to see if transmitted power is within specified range (output power alarm).

3.5.2.7 Receiver Block

The received signal is fed from the input branching filter into a low noise amplifier and a down-converter to the first IF of 974 MHz (Receiver MCM). After bandpass filtering and amplification, the signal is down-converted to the second IF of 140 MHz (IF Converter). A portion of this 140 MHz is used in the RSSI. The 140 MHz signal from IF Converter i s amplified and fed to the cable interface. This double down-conversion with a high first IF enables frequency selection over a wide frequency band, w ith excellent receiver spurious and image rejection.

Receiver Oscillator and Multiplier (MCM)

The local oscillator signal used in the first down-conversion is generated in the same way as for the transmitter oscillator. The signal is multiplied (2 or 4 times depending on channel frequency) and amplified.

3.5.2.8 IF Oscillator

The oscillator consists of a Phase Locked Loop (PLL) and a VCO. It is used for the second down-conversion to 140 MHz. The VCO is also used for adjustment

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of the received 140 MHz signal (through a control signal effecting the division number in the IF PLL).

3.5.2.9 RSSI

A portion of the 140 MHz signal is fed to a calibrated detector in the RSSI (Received Signal Strength Indicator) to provide an accurate receiver input level measurement. The measured level is accessible either as an analog voltage at the alignment port or in dBm through the operation and maintenance system.

3.5.3 Filter Unit

3.5.3.1 RF Loop

The RF Loop is used for test purposes only. When the loop is set, the transmitter frequency is set to receiver frequency and transferred to the receiving side.

MINI-LINKEandEMicro

3.5.3.2 Branching Filter

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3.6 Access Module

The access module is the indoor part of a terminal. It comprises the following types of indoor equipment:

• Access Module Magazine (AMM), which holds the indoor plug-in units. The AMM also provides mechanical housing and electrical interconnections between indoor units through its backplane.

• Modem Unit (MMU) providing traffic interfaces, signal processing and the interface with the radio unit (RAU).

• Switch Multiplexer Unit (SMU) providing additional 2 Mbit/s traffic interfaces, 2/8 and 8/34 Mbit/s multiplexers, switches and control functions for 1+1 protected systems and interfaces with the MMU.

• Service Access Unit (SAU) providing parallel input/output ports, external alarm channel interfaces and service channel interfaces.

• Ethernet Interface Unit (ETU), which enables transmission of Ethernet traffic.

All external interfaces are located at the unit fronts.

Figure 32 Indoor units in an AMM 4U

3530

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3.7 AMM – Access Module Magazine

The Access M odule Magazine (AMM) fits in 19" racks and cabinets, as well as in ETSI and BYB cabinets or directly on a desk/wall.

Different AMMs for different applications are available as standard:

• AMM 1U for a single terminal with one MMU

• AMM 2U-3 for single or dual terminal sites. It can contain one or two MMUs, one SMU and one SAU.

• AMM 4U for more complex multi-terminal sites. It can contain up to four MMUs, two SMUs and one SAU.

MINI-LINKEandEMicro

Figure 33 AMM 1U

Figure 34 AMM 2U-3

3527

3528

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Figure 35 AMM 4U

The units are interconnected through a backplane at the back of the AMM. All external connections are made through connectors at the front of the units.

3529

The AMM is made of aluminum. The side walls guide the units and conduct away the heat. M ounting brackets are screwed to the side walls for installation in 19" racks and cabinets. The aluminum magazine is chromate coated.

A front panel protects the cables at the unit f ronts. It is perforated at the center to let cooling air through and for visibility of LEDs at the unit fronts. The front panel is painted dark gray. It is closed with 2 or 4 screws respectively and folds down vertically around hinges at its lower edge when opened.

Front cables are routed to the left and ri ght of the access module magazine and along the cabinet at the rack side walls.

Cooling

Cooling of the access module is accomplished by forced ventilation.

The cooling air enters at the front of the AMM, flows between the units and out through openings at the back of the magazine on both sides of the backplane.

When the airflow is not sufficient a fan unit placed on top of the AMM in a 19" rack cools the access module, see also Section 8.9 on page 154.

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3.8 MMU – Modem U nit

The MMU is the indoor interface with the radio unit. It is available in the following versions:

• MMU with fixed traffic capacity for:

− 2x2 Mbit/s

− 4x2 or 8 Mbit/s

− 2x8 Mbit/s

− 34+2 Mbit/s

• MMU with agile traffic capacity for:

− 2x2 – 34+2 Mbit/s

MINI-LINKEandEMicro

2x2 Mbit/s

4x2 Mbit/s

2 Mbit/s

8 Mbit/s

34 Mbit/s

8 Mbit/s

MMU 2x2 - 34+2

MMU 2x2

O&M

MMU 4x2/8

O&M

MMU 2x8

O&M

MMU 34+2

O&M

NCC

DC + -

RAU

Figure 36 MMUs

All MMUs are fully independent of frequency band. Together with a radio unit and an antenna, they contain all functions needed for a radio ter m inal with the capacities listed previously.

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4x2 Mbit/s

8/34 Mbit/s

8 Mbit/s

O&M

NCC

DC + -

RAU

5541

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The capacity agile version, MMU 2x2 – 34+2, can be run at all traffic capacities covered by the MMUs with fixed capacities. The MSM software (≥ version

6.0) is used to set the traffic capacity locally on site. Consequently, the traffic capacity of a terminal can be changed without replacement of MMU hardware.

3.8.1 Functional B locks

The following functional blocks are included in the MMU:

• Traffic interfaces and router

• 2/8 multiplexer/demultiplexer (MMUs 4x2/8 Mbit/s only)

• Radio frame multiplexer/demultiplexer for traffic and service channels insertion/extraction and Forward Error Correction (FEC) encoding/decoding

• Transmitting and receiving signal modulation/demodulation

• Cable interface with the radio unit

• Control and supervision processor

• DC/DC converter

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2/8/34 Mbit/s

2/8/2 Mbit/s

Operation

and

Maintenance

Interfaces

Primary

power

supply

Other MMU or SMU

Traffic Interface and

Router

HCC

Control &

Supervision

DC/DC

Converter

Service

channels

Radio Frame

Multiplexer

Radio Frame

Demultiplexer

Service

channels

HCC

NCC

Modulator

Cable

Interface

Demodulator

RCC

To other units within the same access module or to units in another access module

Secondary

voltages

SMU, SAU

Radio

Unit

3535

Figure 37 Block diagram for configuration 2x2, 2x8 and 34+2 Mbit/s

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Other MMU or SMU

4x2 Mbit/s

Traffic

Interface

and

Router

8Mbit/s

2/8

Multiplexer

Demultiplexer

Operation

Maintenance

Interfaces

Other MMU or SMU

Interface

and

Primary

power

supply

Traffic

and

Router

Radio Frame

Multiplexer

Radio Frame

Demultiplexer

HCC

Control &

Supervision

DC/DC

Converter

Figure 38 Block diagram for configuration 4x2/8 Mbit/s

HCC

Service

channels

Modulator

Demodulator

Service

channels

NCC

To other units within the same access module or to units in

another access module

Secondary

voltages

SMU, SAU

RCC

Cable

Interface

Radio Unit

3536

3.8.2 Functional Description

The blocks of the MMU are described in the following text.

3.8.2.1 Traffic Interface and Traffic Router

The traffic inputs and outputs are connected to/from the MMU front and the backplane of the access module.

The traffic signals connected to the MMU front are shaped in a pulse regenerating circuit. The clock is generated and the signal is line-decoded on the transmitting side and line-encoded on the receiving side.

The traffic signals connected to the backplane are routed to other MMUs or SMUs in the same access module. The routing is done without any cabling and the interconnection is controlled from MINI-LINK Netman or from a PC with the MINI-LINK Service Manager (MSM).

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3.8.2.2 2/8 Mbit/s Multiplexer/Demultiplexer (MMU 4x2/8 only)

The 4x2 Mbit/s multiplexing and demultiplexing conforms to ITU-T Rec G.703 and G.742.

In the multiplex direction, the four input 2 Mbit/s baseband signals are received and decoded. The incoming timing information is extracted and the traffic information is read into a buffer memory.

The buffer memory loading ratio is controlled by positive justification. The four synchronized signals are subsequently multiplexed together with a justification indicator and framing information bits into the 8 Mbit/s signal.

In the demultiplex direction, frame alignment is made and the four tributary signals are sent to buffer memories after the framing, stuff indicator and redundant bits have been removed. The crystal-controlled read-out rate from the buffer memory is then filtered to reduce output jitter. Finally the signal is line-coded and transmitted.

MINI-LINKEandEMicro

3.8.2.3 Radio Frame Multiplexer and Forward Error Correction (FEC)

Three different data types are multiplexed into the data stream to be transmitted over the radio path:

•Traffic

• Service channel

• Hop Com munication Channel (HCC)

Transmit Traffic Data

The transmit traffic data is first sent to the multiplexer to assure data rate adaptation (stuffing). If no valid data is present at the input, an AIS signal is inserted at nominal data rate. This means that the data traffic across the hop is replaced with ones (1).

Transmit Service Data Channel

Two independent service channels are provided. Analog and digital service data are handled differently. Clock and sync pulses are sent to the SAU and data from the SAU is fed to the multiplexer. In digital mode data and byte sync pulses are fed to an elastic store before data is read out in synchronism with the composite clock. Appropriate stuffing signals are generated to enable data rate transparency.

Hop Communication Channel

The Hop Communication Channel (HCC) is used for exchange of control and supervision information between near-end and far-end MMUs.

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Multiplexer

The three different data types together with check bits and frame lock bits are sent in a composite data format defined by the frame format that is loaded into a Frame Format RAM. The 12 frame alignment signal bits are placed at the beginning of the frame. Stuffing bits are inserted into the composite frame.

Scrambling and FEC Encoding

Frame

format

Number of bits

CHK

The synchronous scrambler has a length of 2

– 1 and is synchronized each eighth frame (super frame). The FEC bits are inserted according to the frame format and are calculated using an interleaving scheme.

The composite data stream consists of a 125 µs long frame, which contains the above described data types.

Radio Channel Frame Structure

The figure below shows the radio channel frame structure for 2x2 Mbit/s.

FAS T1

12102102 8 2102102102

2 22222162224 2 2 2 122202

FEC

SC1

FEC

SC1

Frame length 125

T1 = Data from traffic channel 1 T2 = Data from traffic channel 2 K1 = Stuffing control T1 K2 = Stuffing control T2 S1 = Not used S2 = Not used SC1 = Not used C1 = HCC1 C2 = HCC2 CHK = Check bits FAS = Frame Alignment Signal FEC = Forward Error Correction

Figure 39 Example of radio channel frame structure, 2x2 Mbit/s

5508

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Composite Rates

The following composite bit rates are used:

• 4.5195 Mbit/s for 2x2 Mbit/s

• 8.9316 Mbit/s for 4x2/8 M bit/s

• 17.6071 Mbit/s for 2x8 Mbit/s

• 37.5369 Mbit/s for 34+2 Mbit/s

3.8.2.4 Modulator

MINI-LINKEandEMicro

The composite data stream from the Radio Frame Multiplexer is C-QPSK* modulated, D/A converted and pulse shaped in a Nyqvist filter to optimize transmit spectrum.

The modulator consists of a phase locked Voltage Controlled Oscillator (VCO) operating at 350 MHz. For test purposes an IF loop signal of 140 MHz is generated by m ixing with a 490 MHz signal.

* C-QPSK (Constant envelope offset - Quadrature Phase Shift Keying) is an offset-QPSK phase modulated signal. It is optimized for high frequency efficiency since it combines the properties of constant envelope with high interference discrimination.

3.8.2.5 Radio Frame Demultiplexer and Forward Error Correction (FEC)

On the receiving side the received composite data stream is demultiplexed and FEC corrected. The frame alignment function searches and locks the receiver to the frame alignment bit patterns in the received data stream.

Descrambling and FEC Decoding

FEC is accomplished using FEC parity bits in combination with a data quality measurement from the demodulator. The descrambler transforms the signal to its original state enabling the demultiplexer to properly distribute the received information to its destinations.

Demultiplexing

Demultiplexing is performed according to the stored frame format. The demultiplexer generates a frame fault alarm if frame synchronization is lost. The number of errored bits in the traffic data stream is measured using parity bits. These are used for BER detection and performance monitoring. Stuffing control bits are processed for the traffic and service channels.

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Received Traffic Data

On the receiving side the following is performed to the traffic data:

• AIS insertion (at signal loss or BER ≤ 10

• AIS detection

• Elastic buffering and clock recovery

• Data alignment compensation and measurement (to enable hitless

• Hitless switching (for 1+1 protection)

Received Service Data Channel

switching)

–3

)

In digital mode data and sync are retrieved and the clock rate is recovered using an elastic buffer. In analog mode synchronization and timing signals are provided together with the data signal.

3.8.2.6 Demodulator

The received 140 MHz signal is AGC amplified and filtered prior to conversion to I/Q baseband signals. The baseband signals are pulse shaped in a Nyqvist filter and A/D converted before being C-QPSK demodulated.

3.8.2.7 Cable Interface

The following signals are frequency multiplexed in the cable interface for further distribution through a coaxial cable to the outdoor radio units:

• 350 MHz transmitting IF signal

• 140 MHz receiving IF signal

•DCpowersupply

• Radio Communication Channel (RCC) signal as an Amplitude Shift Keying

(ASK) signal

In addition to the above, the cable interface includes an overvoltage protection circuit.

3.8.2.8 Control and Supervision

A microprocessor based control and supervision system (CSS) is built into all units in the access module. Its main functions are to collect alar m s, control settings and tests. Failure is indicated on LEDs on the fronts of the units.

The MMU processor communicates with other processors in the access module through the NCC. Exchange of control and supervision data over the hop is

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made through the HCC. The processor also communicates with a PC through the Operation and Maintenance interface.

The MMU processor handles the bit error collection and communicates with processors in the radio unit through the RCC.

See Section 6.1.2 on page 95 for details on the communication channels.

Local setup, error detection and location can be performed by the display and switches on the MMU.

3.8.2.9 DC/DC Converter

The isolated DC/DC converter produces a stable voltage for the outdoor radio unit and secondar y voltages for the MMU electronics. The power supply is after filtering also further distributed to the SMUs and SAUs in the access module.

MINI-LINKEandEMicro

3.8.3 DC Supply

The primar y DC supply to the MMUs is connected in parallel on the backplane for further distribution to all indoor units.

Each MM U supplies its own radio unit.

The MINI-LINK C ross-connect unit (MXU) is supplied separately.

Figure 40 on page 52 shows en example of how the DC supply is connected to the indoor units.

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AMM

Primary DC supply

MMU

SMU

MMU

Figure 40 DC supply connected to the indoor units

Power connection in the backplane

3532

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3.9 SMU – Switch Multiplexer Unit

The SMU provides 1+1 protection switching and/or multiplexing/demultiplexing of 2 Mbit/s channels. It comes in three different versions (SMU Sw, SMU 8x2 and SMU 16x2) for different traffic capacities.

SMU Sw

MINI-LINKEandEMicro

4x2 Mbit/s

(8 Mbit/s) (8 Mbit/s)

4x2 Mbit/s (8 Mbit/s) (8 Mbit/s)

8 Mbit/s O&M

4x2 Mbit/s O&MTP

4x2 Mbit/s O&M

Figure 41 SMUs

3.9.1 Functional Blocks

The S MU basically consists of:

• Traffic interface and router

• Traffic channel switches and control circuitry for 1+1 protection switching and input/output selection for the multiplexers

8 Mbit/s

SMU 8x2

SMU 16x2

34 Mbit/s

4x2 Mbit/s

(8 Mbit/s) (8 Mbit/s)

4x2 Mbit/s

5542

• Control and supervision

• DC/DC converter

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3.9.1.1 SMU Switch

SMU Switch contains the 1+1 MMU selection switch. It can terminate two 2 Mbit/s, four 2 Mbit/s, one 8 Mbit/s, two 8 Mbit/s or one 34 Mbit/s and one 2 Mbit/s traffic channel.

Front or connection 2/8/34 Mbit/s

Operation &

Maintenance Interface

Alarms from MMUs

backplane

2x2 4x2 8 2x8

MMU

Figure 42 SMU Sw block diagram

Traffic

Interface

and

Router

Control &

Supervision

1 + 1

Switch Logic

DC/DC

Converter

Connections to MMUs

NCC

Other units in the access module

MMU 1

MMU 2

Secondary voltages

3553

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3.9.1.2 SMU 8x2

SMU 8x2 contains two independent 2/8 Mbit/s multiplexers/demultiplexers and the 1+1 MMU selection switch. It can terminate up to eight 2 Mbit/s traffic signals.

MINI-LINKEandEMicro

4x2 or 8

Traffic

Connection to front or other SMU/MMU

Interface

and

Router

4x2 or 8

Connection to front or other SMU/MMU

Traffic

Interface

and

Router

Operation & Maintenance Interface

Alarms from MMUs

MMU

Figure 43 SMU 8x2 block diagram

2 2 2 2

2/8

Multiplexer

Demultiplexer

2/8

Multiplexer

Demultiplexer

Control &

Supervision

1 + 1

Switch Logic

DC/DC

Converter

NCC

Traffic Router

8 Mbit/s

Other units in the access module

MMU 1 MMU 2

Secondary voltages

8 8

MMU 1

2x8

MMU 2

2x8

(1+1 only)

3552

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3.9.1.3 SMU 16x2

SMU 16x2 can handle up to sixteen 2 Mbit/s traffic signals. The unit contains four independent 2/8 Mbit/s multiplexers/demultiplexers, one 8/34 Mbit/s multiplexer/demultiplexer and the 1+1 MMU selection switch.

An SMU 16x2 combined with an MMU 34+2 can terminate 17x2 Mbit/s or 4x8+2 Mbit/s for one 1+0 or 1+1 terminal.

An SMU 16x2 combined with two MMUs 8x2 can terminate 8x2 Mbit/s for two 1+0 terminals.

Connection to front or other SMU/MMU

4x2 or 8

Interface

4x2 or 8

Interface

4x2 or 8

Interface

4x2 or 8

Interface

Alarms from MMUs

Traffic

and

Router

Traffic

and

Router

Traffic

and

Router

Traffic

and

Router

Operation & Maintenance Interfaces

2 8

2 2 2

2 2 2 2

2/8

Multiplexer

Demultiplexer

2/8

Multiplexer

Demultiplexer

2/8

Multiplexer

Demultiplexer

2/8

Multiplexer

Demultiplexer

MMU1

2x8, 1+0

Traffic

Router

8 Mbit/s

Control &

Supervision

1 + 1

Switch Logic

MMU2

2x8, 1+0

(When SMU 16x2 is shared between two radios 8x2, 1+0)

8/34

Multiplexer

Demultiplexer

NCC

Traffic

Router

34 Mbit/s

2 Mbit/s is connected to MMU1 and is distributed further to MMU2

Other units in the access module

MMU 1 MMU 2

MMU1

34+2

MMU2

34+2

(1+1 only)

MMU

Figure 44 SMU 16x2 block diagram

As an alternative SMU 16x2 can be used to provide 1+1 protection switching for 4x2 and 8x2 Mbit/s traffic.

DC/DC

Converter

Secondary voltages

3551

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3.9.2 Functional Description

3.9.2.1 Traffic Interface and Traffic Routers

The 2 or 8 Mbit/s traffic inputs and outputs are connected to/from the SMU front and the backplane of the access module.

The traffic signals connected to the SMU front are shaped in a pulse regenerating circuit. The clock is generated and the signal is line-coded.

The 2 or 8 Mbit/s traffic signals connected to/from the backplane are routed to/from other MMUs or SMUs in the same access module. The routing is done without any cabling and the interconnection is controlled from MINI-LINK Netman or from a PC with the MINI-LINK Service Manager (MSM).

3.9.2.2 2/8 Mbit/s Multiplexer/Demultiplexer

MINI-LINKEandEMicro

The four 2 M bit/s signals are multiplexed into an 8 Mbit/s signal on the transmitting side. The 8 Mbit/s signal is demultiplexed into four 2 Mbit/s signals on the r eceiving side.

The multiplexing and demultiplexing conforms to ITU-T Rec G.703 and G.742.

3.9.2.3 8/34 Mbit/s Multiplexer/Demultiplexer

The four 8 M bit/s signals are multiplexed into a 34 Mbit/s signal on the transmitting side. The 34 Mbit/s signal is demultiplexed into four 8 Mbit/s signals on the receiving side. The multiplexing and demultiplexing conforms to ITU-T Rec G.703 and G.751.

3.9.2.4 Control and Supervision

A microprocessor based Control and Supervision System (CSS) is built into all units in the access module. Its main functions are to collect alarms, control settings and tests. Failure is indicated on LEDs on the fronts of the units.

The SMU processor communicates with other processors in the access module through the Node Communication Channel (NCC). The processor also communicates with a PC through the Operation and Maintenance interface.

See section Section 6.1.2 on page 95 for details on the communication channels.

The SMU processor also controls the 1+1 protection switching.

3.9.2.5 DC/DC Converter

The SMU is powered from one or several MMUs. The DC/DC converter in the SMU produces secondary voltages for the SMU electronics.

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3.9.2.6 1+1 Protection Switching

In protected operation, the switching logic controls transmitter and receiver switching for the protected radio section.

The selection is controlled and monitored locally or remotely.

The Switch Multiplexer Unit (SMU) contains all switch logic circuitry for protected systems.

Transmitter Switching

Transmitter selection only applies to hot standby systems. Selection is based on alar m information from the transmitter section of the radio unit or the MMU. Selection can also be made manually from the MMU front or from a PC. An alarm with high priority overrides an alarm with lower priority. The radio unit with the lowest prior ity alarm transmits the signal. See Section 6.1.4.1 on page 97 for a description of the alarms.

Table 1 Prior ity for transmitter switching

Transmitter switching

Alarm Priority

criteria

Switching due to hardware failure

Manual switch mode

MMU does not exist NCC Ra

CSS fail MMU Proc. Hardware

Proc. Software EEPROM

RAU Proc. Hardware

Proc. Software EEPROM

RCC

TX High priority RCC & Radio Frame

Mod Index TX IF Input RF O utput Level

TX Low priority Input BB1, BB2

(1)

Input E1:1 – 4 (MMU)

(1) No switching for BB2 alarm, wayside channel, 17x2 and 34+2 (applies to CSS version 5.0 or later)

Alarm information from the transmitting side is collected in the Control and Supervision processor in each MMU and sent to the Switch Logic in the SMU. The signal is sent to the Radio Unit (RAU) to control the transmitter On/Off function.

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MMU1

SMU

Traffic

MUX

1+1 Switch Logic

MMU 34+2 only

Traffic

2 Mbit/s

MMU2

MUX - Multiplexer CPU - Control & Supervision processor RMX - Radio Frame Multiplexer X - Traffic Router T1 - Traffic channel 1 T2 - Traffic channel 2

Figure 45 1+1 protection switching for the transmitter

CPU

RMX

CPU

Tx On/Off

RAU A

RAU B

3534

Receiver Switching

There are two types of receiver switching: hardware failure switching and hitless switching due to fading. The switching functionality is physically implemented in two different kinds of switch, the RM X switch and a hardware switch, see Figure 46 on page 62. Selection is based on alar m information from the receiver section of the radio unit or the MMU, see Table 2 on page 60. However, hitless switching is performed in the RMX switch. Selection can also be made manually from the MMU front or from a PC. An alarm with high priority overrides an alarm with lower priority. The radio unit with the lowest priority alarm receives the signal. See Section 6.1.4.1 on page 97 for a description of the alarms.

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Table 2 Priority for RMX switching in the receiver

RMX Switch switching

Alarm Priority

criteria (receiver)

Switching due to hardware failure

Manual switch mode

MMU does not exist NCC Ra

CSS fail MMU Proc. Hardware

Proc. Software EEPROM

RAU Proc. Hardware

Proc. Software EEPROM

RCC

RX High priority 1 Demod Clock BB1, 2

Radio ID BER 10

–3

(fixed)

RX Frequency

RX High priority 2 Radio Frame

Hitless switching (error free) due to fading

FEC A detected error will activate

switching (with no Hitless Phase Alarm)

Low

RF level

Threshold but no Hitless

AGC

ase Alarm

RMX switching is accomplished by FIFO buffers and a fast switch. The delay in the buffer is controlled so that the data phase differences in the radio sections (due to cables etc. are compensated. See also Section 8.5.1 on page 143 for restrictions on cable lengths in 1+1 configurations.

The switch is placed before the linecoder in the Radio Frame Multiplexer (RMX). The switch command is synchronized to the bit timing.

Alarm information from the receiving side is collected in the Control and Supervision processor in each MMU and sent to the Switch Logic unit in the SMU.

Alarm generation has a cer tain delay, not critical for fading switching which is hitless because fading means slow traffic degradation.

The control signals from the Switch Logic control the traffic routing of the radio composite signal between the two MMUs.

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Note: Protection switching cannot be made hitless in a working standby

configuration for 4x2 Mbit/s traffic capacity using an SMU Sw. The problem is solved by using an SMU 8x2 or an SMU 16x2 instead.

Table 3 Priority for hardware switching in the receiver

Hardware Switch

Alarm Priority switching criteria (receiver)

Switching due to hardware failure

Manual switch mode

MMU does not exist NCC Ra

CSS failure MMU Proc. Hardware

Proc. Software EEPROM

RAU Proc. Hardware

Proc. Software EEPROM

RCC

MMU MUX System line fault

Transmitter selected If none of the alar ms above

are active, receiver hardware

selection follows transmitter

selection

See section Section 6.1.4.1 on page 97 for an alar m description.

The control signals from the Switch Logic control the hardware switches located in the traffic interface of each MMU. The switch m odes are on/off. The signal from the faulty channel is switched off and the signal from the standby channel is switched on.

The hardware switch follows the switched transmitter, so that the same hardware is selected on the transmitting and receiving sides. Independently the RMX switch selects the best receiver.

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Traffic 2 Mbit/s

Traffic

SMU

MUX

1+1

Switch Logic

T1 T2

MUX - Demultiplexer RMX - Radio Frame Demultiplexer X1 - Hardware Switch (located in the Traffic Router)

X2 - RMX Switch (located in the Radio Frame Demultiplexer)

CPU - Control & Supervision processor T1 - Traffic channel 1 T2 - Traffic channel 2

MMU1

MMU2

MMU 34+2 only

RMX

CPU

RMX

RAU A

RAU B

3533

Figure 46 1+1 protection switching for the receiver

DC Failure

If a DC failure occurs in one of the MMUs in a 1+1 system, the other MMU supplies the SMU and the SAU (if applicable) with DC power. However, when 17x2 Mbit/s capacity is required the 2 Mbit/s signal connected to the MMU with DC failure will be lost. The other 16x2 Mbit/s signals will still be working.

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3.10 SAU – Service Access Unit

The Ser vice Access Unit (SAU) provides additional features such as ser vice channels, parallel inputs/outputs and access to the Exter nal Alarm Channel (EAC) on a MINI-LINK network site. Three versions of the SAU are available, a basic and two expanded versions.

SAU Basic

MINI-LINKEandEMicro

DIG SC 1-4

Figure 47 SAUs

DIG SC 5-8

PHONE

RAC 1

O&M

SAU Exp 1

RAC 2

SAU Exp 2

RAC 2

EAC 1

O&M

EAC 2

EAC 1

BR/EAC 1

USER I/O

EAC 2

BR/EAC 2

USER I/O

5540

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3.10.1 Functional Blocks

The different SAU versions provide the following functions.

SAU Basic

• Two EAC ports

• Eight User Input ports

• Four User Input/Output ports (individually selectable)

• Control and supervision processor

• DC/DC converter

EAC1 EAC2

User In User Out

Operation

and

Maintenance

Interfaces

EAC

Interface

User

In/Out

Processor

MMU

Figure 48 SAU Basic block diagram

Control & Supervision

DC/DC Converter

Other units in

the access module

NCC

Secondary

Voltages

3550

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SAU Exp 1

In addition to the basic version:

• Two digital service channels per radio terminal

•TwoRACports

MINI-LINKEandEMicro

64 kbit/s Fixed line

Fixed line via modem

64 kbit/s

Fixed line

Fixed line via modem

EAC1 EAC2

User In User Out

Operation

and

Maintenance

Interfaces

Digital

Service channel

Interface

ITU-T G.703

RS232

ITU-T G.703

RS232

EAC

Interface

User

In/Out

Processor

2 service channels / radio

RAC

Interface

RAC

Interface

Control & Supervision

NCC

MMU 1 MMU 2 MMU 3 MMU 4

Other units in

the access module

MMU

Figure 49 SAU Exp 1 block diagram

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DC/DC Converter

Secondary

Voltages

3546

MINI-LINKEandEMicro

SAU Exp 2

In addition to the basic version:

• One digital service channel per radio terminal

• One analog service channel per radio terminal

• Service telephone

• Two RAC ports

64 kbit/s

Fixed line

Fixed line via modem

64 kbit/s

Fixed

line Fixed

line via

modem

wire

EAC1 EAC2

User In User Out

2/4

Digital

Service channel

Interface

Analog

Service channel

Interface &

Router

ITU-T

G.703

RS232

ITU-T

G.703

RS232

EAC

Interface

User

In/Out

Processor

1 digital and 1 analog service channel / radio

MMU 1 MMU 2 MMU 3 MMU 4

MMU 1 MMU 2

MMU 3

MMU 4

RAC

Interface

RAC

Interface

Operation

and

Maintenance

Interfaces

MMU

Figure 50 SAU Exp 2 block diagram

Control & Supervision

DC/DC Converter

NCC

Secondary

Voltages

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Other units in

the access module

3547

3.10.2 Functional Description

3.10.2.1 EAC Port

The External Alarm Channel (EAC) ports are used for connecting the alarm and control information to and from other access m odules or MINI-LINK C or MkII terminals at the same site, when building MINI-LINK operation and maintenance networks.

3.10.2.2 User In/Out

At the User Input ports, the user’s alarms are connected to the MINI-LINK operation and maintenance network.

The User Output por ts are used for control of the user’s functions through the MINI-LINK operation and maintenance network. The User Output ports can also be set to connect summar y alarms from the access module to t he users’ supervision system. See Section 6 on page 93 and Section 8.6.1 on page 147 for details.

MINI-LINKEandEMicro

3.10.2.3 Control and Supervision

The SAU processor communicates with other processors in the access module through the Node Communication Channel (NCC). The processor also communicates with a PC through the Operation and Maintenance interface.

The SAU processor controls the user input/output ports and service channel routing. The SAU processor communicates with other MINI-LINK sites through the External Alarm Channel (EAC) or the Remote Alarm Channel (RAC).

See Section 6.1.2 on page 95 for details on the communication channels.

3.10.2.4 DC/DC Converter

The DC/DC converter in the SAU is powered from the MMUs in the access module. It produces secondary voltages for the SAU circuitry.

3.10.2.5 Digital Service Channels (Exp 1 and Exp 2 only)

The digital service channels provide extra data channels over the hop. For example, they can be used for obtaining sur veillance data from equipment not installed in the AMM. The service channels are available on t he front of the SAU and are interconnected to the MMU through the backplane of the access module, without any cabling.

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3.10.2.6 RAC (Exp 1 and Exp 2 only)

The Remote Alarm Channel (RAC) is used when MINI-LINK terminals on different sites c annot be reached by air.

The R AC has two por ts, each one with a selectable interface: RS 232C for analog fixed lines (through modem) and digital ITU-T Rec G.703 for 64 kbit/s fixed lines.

3.10.2.7 Analog Service Channel (Exp 2 only)

The analog service channel is used for speech communication between MINI-LINK sites. The ser vice channel is connected from the service telephone to the terminals in the AM M. This connection is controlled through MINI-LINK Netman or MSM. The service channels are distributed to remote sites through the MMUs and the RAUs.

3.10.2.8 Service Telephone (Exp 2 only)

Service Telephone (Exp 2 only) The SAU Exp 2 version is delivered with a two-wire service telephone. The two-digit number for the telephone is set in M SM. A general call can be made simultaneously to all telephones or a selective call can be made to a specific number.

3.10.2.9 SAU Stand Alone

SAU stand alone (Exp 1 and Exp 2) can be used for connection of a remote MINI-LINK C or M kII cluster through the RAC through a fixed line. The RAC ports provide both the RS 232C interface for connection through modem and the 64 kbit/s digital interface. Two SAUs are required, one at each end. SAU stand alone (Exp1 and E xp 2) can also be used to connect a MINI-LINK network to a remote O&M center through a 64 kbit/s fixed line. The SAU stand alone (any version) can be used for connection of user input/output interfaces. The service channels in the SAU cannot be used.

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3.11 ETU – Ethernet Interface Unit

The ETU enables transmission of Ethernet traffic over a MINI-LINK E hop or network. A typical application of the ETU is LAN-to-LAN interconnection.

The ETU is an indoor plug-in unit that fits into any available AMM slot. It has one Ethernet interface, either for 10BASE-T or 100BASE-TX, for connection to a LAN. Three G.703 interfaces – 2, 8 and 34 Mbit/s (E1, E2 and E3) – are available for connection to an MMU or possibly an SMU. The selected G.703 interface can work in combination with either 10BASE-T or 100BASE-TX, providing selectable throughput capacity.

Ethernet traffic from the ETU can be combined with other traffic such as PBX, connected directly to the MMU. When using 34+2 Mbit/s traffic capacity for example, 34 Mbit/s can be used for Ethernet data and 2 Mbit/s for voice transmission.

MINI-LINKEandEMicro

Ethernet LAN

PBX

10BASE-T/

100BASE-TX

ETU

Auxiliary

Alarm

E1/E2/E3

MMU

n x E1/E2

SMU+MMU

RAU

Figure 51 ETU used for LAN-to-LAN interconnection in combination with PBX traffic

3.11.1 Functional Description

10BASE-T/

100BASE-TX

Possible

MINI-LINK E

repeater or network

EthernetLAN

ETU

E1/E2/E3

MMU

SMU+MMU

PBX

Auxiliary Alarm

n x E1/E2

MINI-LINK

Netman

RAU

3610

The basic function of the ETU is to convert Ethernet traffic to a PDH data stream with a chosen traffic rate and vice-versa.

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2 Mbit/s

34 Mbit/s

8 Mbit/s

O&M

Figure 52 ETU

Below follows a description of the ETU main functions.

3.11.1.1 Autonegotiation

The function enables automatic configuration of duplex mode (full or half) and Ethernet traffic rate based on the configuration of the connected device, for example a switch or a router. Autonegotiation is implemented according t o IEEE 802.3 and can be switched off to allow manual configuration.

3.11.1.2 Transparency for VLAN

The ETU is transparent to Ethernet frames carrying VLAN tags, according to IEEE 802.1Q.

The E TU is transparent to Cisco ISL encapsulated Ethernet frames of type 0000 with a maximum length of 1548 octets.

3.11.1.3 Self-learning MAC Level Bridge

10BASE-T/100BASE-TX

ALARM

4490

The ETU has self-learning MAC level bridge functionality, according to IEEE

802.1D, when operating at 10BASE-T. It learns the MAC addresses of all devices in the connected LAN and does not transfer frames addressed to these devices to the LAN at the far-end, thus avoiding unnecessary LAN-to-LAN traffic.

3.11.1.4 Flow Control

The ETU supports flow control according to IEEE 802.3 (MAC Control PAUSE operation). The function is used to temporarily pause transmission of traffic to a congested device by s ending out multicast PAUSE frames.

3.11.1.5 RED Algorithm

The RED algorithm is used to improve the performance of the ETU in case of congestion, by randomly discarding packets when buffers are almost full. The

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function can be turned on or off. It is recommended to have it on when the ETU becomes congested and flow control cannot be used.

3.11.1.6 Control and Supervision

The configuration of the ETU is made locally using a terminal emulator, for example Windows HyperTerminal. The PC is connected to the O&M port and can also be used to display statistics on Ethernet traffic.

By connecting the ALARM port on the ETU to the NCC port (auxiliary alarm input) on the MMU, an alarm can be displayed in Netman or MSM.

The ETU is equipped with LEDs on the front panel providing status indication according to the tables below.

Table 4 Yellow LED indication

MINI-LINKEandEMicro

ETU state Yellow L E D s t a t e Indication

Startup

Running

Brief flash OK

Flashing Transmitting and/or

receiving Ether net traffic

On Ethernet link up

Off Ethernet link down

Table 5 Red LED indication

ETU state Red LED state Indication

Startup

Running

On Processor control

Off OK

On Unit failure

Table 6 Green LED indication

TU state

tartup

Running

Green LED state

On OK

ndication

Off Power supply failure

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3.11.2 Functional Blocks

The ETU consists of the following functional blocks:

• Ethernet logic

• Traffic converter and buffer

• G.703 logic

Figure 53 ETU block diagram

3.11.2.1 Ethernet Logic

The block includes an Ethernet interface circuit.

Incoming Ethernet frames are captured, the preambles are cut off and the remaining frames are transferred to the next functional block.

10BASE-T/100BASE-TX

O&M LEDs

E1/E2/E3

ALARM

Ethernet

logic

Traffic

converter

and buffer

G.703

logic

3611

Ethernet frames for transmission are received and preambles are added before being transmitted.

3.11.2.2 Traffic Converter and Buffer

The Ethernet frames from the Ethernet side are stored in a buffer until they are transmitted. Before the frames are sent to the G.703 logic they are encapsulated in HDLC frames.

The received HDLC frames are captured from the data received from the G.703 logic block, the HDLC overhead is cut off and the remaining Ethernet frames arestoredinabuffer.

The block also implements the O&M and LED functions.

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3.11.2.3 G.703 Logic

The block includes the PDH interface circuit where the incoming PDH traffic is decoded from HDB3 and transferred to the next functional block. The outgoing traffic is converted t o HDB3 and sent to the MMU or possibly SMU.

The block also implements the interface for the ALARM signal.

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3.12 Traffic Routing

The built-in software cabling between the indoor units within an AMM offers:

• Reduced requirement for external cabling at repeater sites which means higher reliability and lower instal

and multi-terminal

lation and cable costs.

• Reduced requirement for SMUs in some configurations, which means that hardware costs can be reduced.

• 8 Mbit/s traffic connections on the SMU (8x2 and 16x2) fronts which means that multiples of both 2 Mbit/s and 8 Mbit/s traffic connections are available.

The interconnections are made in the backplane and it is controlled from a PC with the MINI-LINK Service Manager (MSM) or the MINI-LINK Netman. A traffic routing setup is possible from any node in the network.

The following pages include three examples of traffic routing.

Example 1: Traffic routing at a repeater site

In this example two 2 Mbit/s channels are repeated from one terminal to another. The two terminals at the repeater site (called Feeder and Sub-link in the figure below) are connected through the backplane of the access module.

Feeder

Sub-link

Outdoor units Access module

Feeder Radio Unit

1+0

2x2 Mbit/s

MMU 2x2

AMM

Backplane

MMU 2x2

2x2 Mbit/s

Figure 54 Traffic routing at a 2x2 Mbit/s repeater site

1+0

Sub-link Radio Unit

3544

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Example 2: Traffic routing at a repeater site with drop/insert

In this example two 8 Mbit/s channels are repeated from the feeder to the sub-link. Up to nine 2 Mbit/s channels (or two 8 Mbit/s channels plus one 2 Mbit/s channel) can be dropped/inserted at the site.

Feeder Radio Unit

17x2 Mbit/s

Outdoor units Access module

MMU 34+2

34+2 Mbit/s

SMU 16x2

8/34

Multiplexer/

Demultiplexer

Feeder

1+1

AMM

drop/insert

2/8

Multiplexer/

Demultiplexer

2/8

Multiplexer/

Demultiplexer

2/8

Multiplexer/

Demultiplexer

2/8

Multiplexer/

Demultiplexer

Front connections

Sub-link

Backplane

9x2 Mbit/s

2x8 Mbit/s

1+0

8x2 Mbit/s

MMU 2x8

Sub-link Radio Unit

3545

Figure 55 Traffic routing at a repeater site with drop/inser t

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Example 3: Traffic routing at a multi-terminal site

In this example two 8 Mbit/s channels are distributed from the feeder to sub-link 1 and two 2 Mbit/s channels are distributed to sub-link 2. Up to seven 2 Mbit/s channels can be dropped/inserted at the site.

Feeder Radio

Unit

Feeder Radio Unit

17x2 Mbit/s

Outdoor units Access module

MMU 34+2

34+2 Mbit/s

SMU 16x2

8/34

Multiplexer/

Demultiplexer

1+1

Feeder

drop/insert

2/8

Multiplexer/

Demultiplexer

2/8

Multiplexer/

Demultiplexer

2/8

Multiplexer/

Demultiplexer

2/8

Multiplexer/

Demultiplexer

Sub-link 1

Sub-link 2

AMM

2x8 Mbit/s

2x2 Mbit/s

1+0

Backplane

1+0

MMU 2x8

MMU 2x2

8x2 Mbit/s

2x2 Mbit/s

Sub-link 1 Radio Unit

Sub-link 2 Radio Unit

MMU 34+2

Front connections

Figure 56 Traffic routing at a multi-terminal site

7x2 Mbit/s

3543

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3.13 Upgrading

3.13.1 Change of transmission capacity

The capacity agile MMU 2x2 – 34+2 allows capacity upgrade without hardware replacement. This is done by using MINI-LINK Service Manager (MSM).

When using an MMU with fixed traffic capacity, the upgrade is achieved by exchanging it for an MMU with a higher traffic capacity.

When 8x2 or 17x2 Mbit/s is required an SMU has to be added. In some cases the AMM 1U has to be changed to an AMM 2U-3. This applies to both the capacity agile MMU and MMUs with fixed traffic capacity. See the MINI-LINK E and E Micro Product Catalog (AE/LZT 110 2011) for more information.

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4MINI-LINKEMicro

4.1 General

The all-outdoor terminal, MINI-LINK E Micro, comprises an outdoor radio unit (RTU), an antenna with mounting kit and an optional Radio Connection Box (RCB). It is intended for all-outdoor solutions where it is combined with other all-outdoor equipment.

The RTU can be combined with a wide range of antennas for integrated or separate installation.

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4.2 RTU – Radio Unit

The radio unit, RTU, is an all-outdoor radio for the 23 and 38 GHz frequency bands, with software selectable traffic capacity of 2 or 2x2 Mbit/s (38 GHz only 2x2 Mbit/s).

The operating frequency is set on site using the MSM software on a PC.

The RTU, is a weatherproof box painted light gray, with a handle for lifting and hoisting. It connects to the antenna unit at the waveguide port. It also has two hooks and catches to guide it for easier handling, when fitting to or removing from an integrated antenna.

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Figure 57 Radio unit RTU

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The RTU consists of cover, frame, connection unit, modem board, microwave unit and filter unit.

The connection unit forms the bottom of the radio unit c over and it holds alarm indicators (LEDs) and connectors for traffic, grounding, DC power, antenna alignment and operation and maintenance.

The connection unit is also equipped with lightning protection.

The modem board consists of circuits for baseband encoding/decoding and the traffic interface.

The microwave unit is a circuit board assembly, consisting of a radio board and two MCMs (Multi-chip Modules) for the transmitting and receiving parts of the radio unit. The high frequency MCM components are shielded with an aluminum cover. In addition, it contains the DC/DC converters, control and supervision functions and components for IF signal processing.

The filter unit consists of two branching filters and an impedance T-junction that is the interface with the antenna.

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Cover

MINI-LINKEandEMicro

Frame

Microwave unit

Modem board

Figure 58 RTU parts

Filter unit

Earthing screw

Connection unit

1234

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4.3 Block Diagram

Connection Unit with lig htning protection

Command

& Control Signal

To Alignment Port

Modem Board

Traffic Interface, Radio Frame Multiplexer and Demultiplexer

RSSI

Control & Supervision Processor

DC/DC Converter

Transmit Baseband

Processing

Baseband

Processing

Alarm and Control

Signal

Receive

Signal

Receive IF Signal,

140 MHz

Figure 59 RTU block diagram

Secondary

voltages

Microwave Unit

FREQUENCY CONTROL TX

Processor Interface

FREQUENCY CONTROL IF

Oscillator

834 MHz

140 MHz

To control and supervision processor

Down Converter

Transmitter ( MCM )

Transmitter

Oscillator

IF Converter

Filter & Amplifier

974 MHz

Multiplier

Receiver

Oscillator

Multiplier

Down

Converter

OUTPUT LEVEL SET

Output

Level

Control

Receiver ( MCM )

FREQUENCY CONTROL RX

Low Noise

Power

Amplifier

TX OFF

Loop

Filter Unit

Branching

Filter

Branching Filter

Antenna

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4.4 Modem Board

Modem Board

2 Mbit/s

Figure 60 Modem board

Traffic

Interface

Radio Frame

Multiplexer

Radio Frame

Demultiplexer

Modulator

Demodulator

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The traffic interface provides 2 or 2x2 Mbit/s long-haul traffic functions.

The purpose of the radio frame multiplexer / demultiplexer is multiplexing / demultiplexing of different service type data (traffic, control and supervision data) being sent over a hop.

In the transmitting direction, radio frame multiplexing, scrambling, Forward Error Correction (FEC) encoding and modulation are applied.

In the receiving direction, descrambling, FEC decoding, radio frame demultiplexing and demodulation are applied.

4.4.1 Traffic Interface

Traffic inputs and outputs are connected to/from the radio unit.

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Traffic signals are shaped in a pulse regenerating circuit. The clock is generated and the signal is line-decoded on the transmitting side and line-encoded on the receiving side.

4.4.2 Radio Frame Multiplexer and Forward Error Correction (FEC)

Two different data types are multiplexed into the data stream to be transmitted over the radio path:

•Traffic

• Hop Com munication Channel (HCC)

Transmit Traffic Data

Two independent data channels can be sent by the radio. The data is sent to the multiplexer to assure data rate adaptation (stuffing). If no valid data is present at the input, an AIS signal is inserted at nominal data rate.

Hop Com munication Channel (HCC)

HCC is a data channel for exchange of control and supervision information between near and far-end radios.

Multiplexer

In the transmitting direction, traffic and hop communication data together with check bits and frame lock bits are sent in a composite data format defined by the frame format that is loaded into a Frame Format RAM. The 12 frame alignment signal bits are placed at the start of the frame. Parity bits are inserted for control of traffic data and stuffing bits are inserted into the composite frame.

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Scrambling and FEC Encoding

Frame

format

Number of bits

CHK

The synchronous scrambler has a length of 2

– 1 and is synchronized every eighth frame (super frame). The FEC bits are inserted according to the frame format and are calculated using an interleaving scheme.

The composite data stream consists of a 125 µs long frame, which contains the above described data types.

Radio Channel Frame Structure

The figure below shows the radio channel frame structure for 2x2 Mbit/s.

FAS T1

12102102 8 2102102102

2 22222162224 2 2 2 122202

FEC

SC1

FEC

SC1

Frame length 125

Figure 61 Example of radio channel frame structure, 2x2 Mbit/s

Composite rates

The following composite bit rates are used:

• 2.2758 Mbit/s for 2 M bit/s

• 4.5195 Mbit/s for 2x2 Mbit/s

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4.4.3 Transmit Baseband Signal Processing

The composite data stream from the Radio Frame Multiplexer is C-QPSK* modulated, D/A converted and pulse shaped in a Nyqvist filter to optimize the transm it spectrum.

PSK (Constant envelope offset – Quadrature Phase Shift Keying) is

*C-Q

fset-QPSK phase modulated signal. It is optimized for high frequency

an of

ciency since it combines the properties of constant envelope with high

effi

rference discrimination.

inte

4.4.4 Radio Frame Demultiplexer and Forward Error Correction (FEC)

Descrambling and FEC decoding

Demultiplexing

Demultiplexing is performed according to the stored frame format. The demultiplexer generates a frame fault alarm if frame synchronization is lost. The number of errored bits in the traffic data stream is measured using par ity bits. These are used for BER detection and performance monitoring. Stuffing control bits are processed for the traffic channels

Received Traffic Data

On the receiving side the following is performed to the traffic data:

• AIS insertion (at signal loss or BER ≤ 10

–3

)

• AIS detection

• Elastic buffering and clock recovery

4.4.5 Receive Baseband Signal Processing

The received 140 MHz signal is AGC amplified and f iltered before conversion to I/Q baseband signals. The baseband signals are pulse shaped in a Nyqvist filter and A/D converted before being C-QPSK demodulated.

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4.4.6 RSSI

A portion of the 140 MHz signal is fed to a calibrated detector in the Received Signal Strength Indicator (RSSI) to provide an accurate receiver input level measurement. The measured level is accessible either as an analog voltage at the alignment port or in dBm through the operation and maintenance system.

4.5 Microwave Unit

4.5.1 DC/DC Converter

The DC/DC converter provides stable voltages for the RTU.

4.5.2 Control and Super vision Processor

The processor for radio unit control and supervision is situated on the microwave unit circuit board. Its main functions are descr ibed below.

Alarm collection

Alarm and status signals are collected, resulting in summary status signals (A and B-alarms). Alarms are visualized by LEDs on the radio unit.

Command Handling

Commands such as transmitter activation/deactivation, channel frequency setting, output power setting and RF loop activation/deactivation are executed.

Radio Terminal Control and Message Handling

In addition to the above, the processor controls the radio unit’s internal processes and loops.

4.5.3 Transmitter Block

Transmitter Oscillator (MCM)

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Multiplier (MCM)

The VCO signal is amplified and frequency multiplied (2 or 4 times depending on the frequency band).

Power Amplifier (MCM)

Adjusting the gain of the power amplifier controls the transmitter output power. The output power is set in steps of 1 dB through the operation and maintenance system. The transmitter can be switched on or off by switching the final amplifier.

4.5.4 Output Level Control

The output signal level from the final amplifiers are analyzed in order to see if transmitted power is within specified range (output power alarm).

MINI-LINKEandEMicro

4.5.5 Receiver Block

The received signal is fed from the input branching filter into a low noise amplifier and a down-converter to the first IF of 974 MHz (Receiver MCM). After bandpass filtering and amplification, the signal is down-converted to the second IF of 140 MHz (IF Converter). A portion of this 140 MHz is used in the RSSI. The 140 MHz signal from the IF Converter is amplified and fed to the modem board. This double down-conversion with a high first IF enables frequency selection over a wide frequency band, with excellent receiver spurious and image rejection.

Receiver Oscillator and Multiplier (MCM)

4.5.6 IF Oscillator

The oscillator consists of a Phase Locked Loop (PLL) and a VCO. It is used for the second down-conversion to 140 MHz. The VCO is also used for adjustment of the received 140 MHz signal (through a control signal effecting the division number in the PLL).

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4.6 Filter Unit

4.6.1 RF Loop

The RF Loop is used for test purposes only. When the l oop is set, the transmitter frequency is set to receiver frequency and transferred to the receiving side.

4.6.2 Branching Filter

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5 Antennas

5.1 Antenna Description

The available antennas range from 0.2 m up to 3.0 m in diameter. For detailed information, see the MINI-LINK E and E Micro Product Catalog (AE/LZT 110

2011).

All antennas up to 1.8 m in diameter, named compact antennas, are normally used in integrated installation where the radio unit is f itted directly to the rear of the antenna. They are made of aluminum, painted light gray and have a standard IEC 154 type B waveguide interface. The antennas can be adjusted for vertical or horizontal polarization by adjusting the waveguide interface. All high performance versions have an integrated radome.

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All antennas can also be fitted separately from the radio unit, using a flexible waveguide to connect to the radio. For separate installation, any antenna with IEC 154 type B waveguide interface can be used.

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Figure 62 0.2 m, 0.3 m and 0.6 compact antennas integrated with RAU2

Figure 63 0.3 m and 0.6 compact antennas integrated with RAU1

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5.2 Antenna Installation

This section describes the mounting kits for the 0.2 m, 0.3 m and 0.6 m compact antennas.

An antenna mounting kit consists of two rigid, extruded aluminum brackets connected with two stainless steel screws along the azimuth axis. The brackets are anodized and have threaded and unthreaded holes to provide adjustment of the antenna in azimuth and elevation.

The support can be clamped to poles with a diameter of 50 – 120 mm or on L-profiles 40 x 40 x 5 – 80 x 80 x 8 mm with two anodized aluminum clamps.

All screws and nuts for connection and adjustment are in stainless steel. NordLock washers are used to secure the screws.

Figure 64 Mounting kit for the 0.2 m compact antenna

The 0.2 m compact antenna mounting kit can be adjusted by ±13 and by ±90

in azimuth.

Figure 65 M ounting kit for 0.3 m and 0.6 m compact antennas

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in elevation

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The mounting kit for 0.3 m and 0.6 m compact antennas can be adjusted by ±15

in elevation and ±40 in azimuth. Both elevation and azimuth have a

mechanism for fine adjustment.

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6 Management System

6.1 Operation and Maintenance Facilities

All MINI-LINK E and E Micro units have an integrated Control and Supervision System (CSS) that continuously monitors the transmission quality and alarm status. The information is available through the supervision channel, which is extended throughout the MINI-LINK network.

Communication with CSS is carried out by means of a PC, along with MINI-LINK management software. The MINI-LINK Netman software package is used for central supervision of large networks. A portable PC with MINI-LINK Service Manager (MSM) is used for installation and field service.

MINI-LINKEandEMicro

See Netman Technical Description (AE/LZT 110 5048) for more information on management system.

PSTN back-up

or other line

Leased line or

other fixed channel

Radio Unit/ Antenna Module

Access Module

Figure 66 General example of a supervised MI

Operation & maintenance

centre

3509

NI-LINK network

CSS offers the following main features:

• Universal access: the system can be reached from any indoor unit or MINI-LINK E Micro

• Permission of multi-user applications

• Performance monitoring

• Performance and alarm log

• Alarm notification, transfer and status collection

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• User inputs (optional SAU)

• User outputs (optional SAU)

• Near-end and far-end loop-back facilities

• Two built-in service channels for independent data or voice communications

• Traffic routing

• Software selectable output power

• Traffic capacity of the MMU 2x2 – 34+2 is selectable locally on site using

(optional SAU)

MSM

6.1.1 Data Communication Network

The MINI-LINK E network can be divided into three networks: the traffic network, t he Data Communication Network (DCN) and the service channel network. The DCN is the network that provides connection between Management Systems and MINI-LINK terminals.

The teminals can be connected to each other and thereby forming a sub-network. The DCN normally consists of a number of sub-networks. Sub-networks are isolated from each other and are each assigned to a specific Netman Server.

The management traffic consists of configuration, status information and error messages.

For more information on DCN, see Netman Technical Description (AE/LZT 110 5048).

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Ericsson MINI-LINK E, MINI-LINK E Micro Technical Description

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Introduction

1.1 General

1.2 Applications

1.3 Main Features

1.4 Related Documents

2 Product Program

2.1 Introduction

2.2 MINI-LINK E

2.3 MINI-LINK E Micro

2.4 Network Management

3MINI-LINKE

3.1 General

3.2 Radio Units

3.3 RAU1 (7-E and 8-E)

3.4 RAU1 (15-E, 18-E, 2 3-E, 26-E and 38-E)

3.5 RAU2

3.6 Access Module

3.7 AMM – Access Module Magazine

3.12 Traffic Routing

3.13 Upgrading

4MINI-LINKEMicro

4.1 General

4.3 Block Diagram

4.4 Modem Board

4.5 Microwave Unit

4.6 Filter Unit

5 Antennas

5.1 Antenna Description

5.2 Antenna Installation

6 Management System

6.1 Operation and Maintenance Facilities