Ericsson MINI-LINK BAS Technical Description
MINI-LINK BAS
Technical Description
Ericsson is the leading provider
in the new telecom world,
with communications solutions
that combine telecom and datacom technologies
with freedom of mobility for the user.
With more than 100,000 employees in 140 countries,
Ericsson simplifies communications for its Customers
- network operators, service providers,
enterprises and consumers -
the world over.
Ericsson Information on Demand Database can be
addressed at: http://www.ericsson.com
We continuously develop and improve our products and therefore
reserve the right to alter technical details without notice.
Ericsson Microwave Systems AB
Microwave Radio Division
S-431 84 Mölndal
SWEDEN
Telephone: +46 31 747 00 00
Fax: +46 31 27 72 25
EN/LZB 111 0542 P2B
© Ericsson Microwave Systems AB 2000
Designed and developed by
Ericsson Lab Italy
R&D Global Product Center
via Cadorna 73, 20090 Vimodrone, Milan
ITALY
1 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
MINI-LINK BAS
Technical Description
Copyright Ericsson 2000
MINI-LINK BAS 2
Technical Description EN/LZB 111 0542 P2B
Foreword
The customer documentation includes all information and documents
necessary for a basic knowledge of Ericsson systems.
The above said documentation has its own code number and release;
the latter is subject to changes whenever eventual updates may occur.
The customer documentation is subdivided into the following
manuals:
• AT Installation Manual
• Installation Manual
• Operation and Maintenance Manual
• Planning and Engineering Manual
• Product Catalogue
• Technical Description
The purpose of this description is to support the reader with detailed
information on the product from technical and functional points of
view.
It supplies all information necessary to understand equipment
operation and technical characteristics. This document is addressed to
the network planner and operation personnel who will find the
information they are interested in.
Use of any trademark in this document is not intended in any way to
infringe on the rights of the trademark holder.
3 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
Preface
For more information, please refer to the MINI-LINK BAS Product
Catalogue.
You may also contact your Ericsson representative or the area sales
manager for your country at:
Ericsson Microwave Systems AB
Microwave Radio Division
S-431 84 Mölndal
SWEDEN
Telephone: +46 31 747 00 00
Fax: +46 31 27 72 25
Please contact your Ericsson representative for latest details and data.
The specifications or configuration contained in this document are
subject to change without notice due to continuous design
improvement.
If there is any conflict between this document and Compliance
statements, the latter will supersede this document.
Please refer to the “Information Revision” document for details about
the updating level of the present description.
The MINI-LINK BAS and the relative Customer documentation have
been designed and developed by:
Ericsson Lab Italy
R&D Global Product Center
via Cadorna 73
20090 Vimodrone
Milan
ITALY.
MINI-LINK BAS 4
Technical Description EN/LZB 111 0542 P2B
Contents
1 Introduction............................. 1-1
1.1 General Information..................................1-2
1.2 Manual Structure.......................................1-2
1.3 General Overview.....................................1-3
1.3.1 Opportunities.....................................................1-3
1.3.2 Product Benefits................................................1-4
1.4 Terminology..............................................1-6
2 System Description ................ 2-1
2.1 Overview...................................................2-2
2.2 System Components.................................2-4
2.2.1 AT .....................................................................2-5
2.2.1.1 FlexNU................................................................2-6
2.2.1.2 ODU....................................................................2-6
2.2.1.3 ACT.....................................................................2-6
2.2.2 RN.....................................................................2-6
2.2.2.1 R-AAS.................................................................2-8
2.2.2.2 ODU..................................................................2-10
2.2.3 C-AAS.............................................................2-11
2.2.4 Control and Management................................2-11
2.2.4.1 CP.....................................................................2-11
2.2.4.2 EM.....................................................................2-11
2.3 Configuration Limits................................2-12
2.4 System Interfaces...................................2-12
2.4.1 Intra-System Interfaces...................................2-12
2.4.2 Customer Service Interfaces...........................2-13
2.4.3 Local Exchange/ISP Interfaces.......................2-14
3 Network Architecture.............. 3-1
3.1 Introduction...............................................3-2
3.2 SN.............................................................3-3
3.2.1 SN R-AAS Stand-alone.....................................3-3
3.2.2 SN C-AAS.........................................................3-4
3.2.3 Generic MINI-LINK BAS Network......................3-6
3.2.4 SN connection to CP and EM............................3-7
3.2.5 Examples of an Overall Network.......................3-8
3.3 System Synchronisation ...........................3-9
3.4 Traffic Routing........................................3-10
5 MINI-LINK BAS
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3.5 Typical Network Applications...................3-11
4 End-User Services...................4-1
4.1 Introduction...............................................4-2
4.2 Data Communication.................................4-3
4.2.1 Ethernet Frames Encapsulation According
to RFC 1483......................................................4-4
4.3 CE Services..............................................4-6
5 Physical and MAC Layers.......5-1
5.1 Introduction...............................................5-2
5.2 Physical Layer...........................................5-3
5.2.1 Media Control Loops .........................................5-5
5.2.1.1 Amplitude Control Loop....................................... 5-6
5.2.1.2 Frequency Control Loop...................................... 5-6
5.2.1.3 Modulation Index RCL, Uplink and Downlink....... 5-7
5.2.1.4 Clock Phase RCL, Uplink only............................5-7
5.2.2 Radio Link Adaptation .......................................5-8
5.2.3 Modulation.........................................................5-8
5.3 RAUs ........................................................5-9
5.3.1 Block Diagram.................................................5-10
5.3.1.1 Trans mi tter On/Off Switch................................. 5-13
5.4 LLC Layer ...............................................5-14
5.4.1 TDMA/TDM Framing .......................................5-14
5.4.1.1 Downlink TDM Fram e.......................................5-14
5.4.1.2 Uplink TDMA Frame......................................... 5-15
5.4.2 Frame Alignment.............................................5-17
5.4.3 Scrambling.......................................................5-17
5.4.4 FEC.................................................................5-17
5.4.5 Performance Monitoring..................................5-18
5.5 MAC Layer..............................................5-20
5.5.1 Sign-On...........................................................5-22
5.5.2 Distance Ranging............................................5-22
5.5.3 Radio Bandwidth Limitation.............................5-23
5.6 Processing Flow......................................5-24
5.6.1 Downlink Processing Flow...............................5-24
5.6.2 Uplink Processing Flow...................................5-25
5.6.3 RC Cells Insertion............................................5-26
6 Management and Control6-1
6.1 Introduction...............................................6-2
6.2 Management System................................6-3
6.3 Control Architecture ..................................6-4
6.3.1 Hierarchy...........................................................6-4
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6.3.2 Board Relay ......................................................6-5
6.3.3 ICS/ATM Connection Rules..............................6-5
6.3.3.1 Configuration Requirements................................6-5
6.3.3.2 Interface Requirements.......................................6-6
6.4 EM............................................................6-9
6.4.1 Basic Platform.................................................6-10
6.4.2 Generic Services.............................................6-12
6.4.3 Specific Services.............................................6-14
6.5 CP...........................................................6-15
6.5.1 Interface Handlers ...........................................6-16
6.5.2 Main Applications............................................6-16
6.5.2.1 Connection Handler...........................................6-17
6.5.2.2 Equipment Handler............................................6-17
6.5.2.3 Alarm Handler ...................................................6-18
6.5.3 HH (Device Handlers).....................................6-18
6.5.4 MRS & MRI.....................................................6-19
6.6 Equipment Management.........................6-20
6.6.1 Equipment Hardware Configuration................6-20
6.6.2 Equipment Software Configuration..................6-20
6.6.3 Equipment Supervisioning...............................6-21
6.6.4 Equipment Errors and Error Handling.............6-22
6.6.5 Equipment Audit..............................................6-22
6.7 Connection Management........................6-23
6.7.1 Connection Configuration................................6-23
6.7.2 Cross Connection Re establishment...............6-24
6.7.3 Connection Supervisi on..................................6-24
6.8 Alarm and Event Management ................6-25
6.8.1 Alarm Correlation............................................6-25
6.8.2 Alarm Suppression..........................................6-25
6.8.3 Active Alarm List .............................................6-25
6.8.4 Alarm and Event Log.......................................6-26
6.8.5 Alarm Severity .................................................6-26
6.9 Performance Management......................6-27
6.10 Database Management...........................6-27
6.10.1 Persistent Data................................................6-27
6.10.2 Backup and Restore........................................6-28
6.10.3 Atomicity of Transactions................................6-28
6.11 Internal Communication..........................6-29
6.11.1 Communication between EM and CP.............6-29
6.11.2 Communication between CP and DP..............6-29
6.12 Recovery Procedures .............................6-31
6.12.1 Initial Start.......................................................6-31
6.12.2 Cold Restart....................................................6-31
6.12.2.1 System Cold Restart..........................................6-31
6.12.2.2 Board Cold Restart............................................6-32
6.12.3 Hot Restart......................................................6-32
7 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
7 ATM Transport and
Multiplexing ..............................7-1
7.1 Introduction...............................................7-2
7.2 Virtual Connections...................................7-3
7.2.1 VP/VC Connection Plan....................................7-4
7.2.2 Use of VPI/VCI Values ......................................7-4
7.3 Service Categories....................................7-6
7.3.1 Connection Admission Control..........................7-6
7.4 R-AAS and C-AAS (CE Shelf)...................7-7
7.5 FlexNU......................................................7-8
7.6 ATM Fault Management............................7-8
8 Equipment Practice and
Power ........................................8-1
8.1 Introduction...............................................8-2
8.2 Hub Site....................................................8-2
8.2.1 R-AAS, Radio-ATM Access Shelf......................8-2
8.2.1.1 PSU.................................................................... 8-3
8.2.1.2 Fan Unit.............................................................. 8-3
8.2.2 RAU...................................................................8-4
8.2.3 Antenna.............................................................8-5
8.2.3.1 Antenna for Point-to-Multipoint Connection ......... 8-5
8.2.3.2 Antenna for Point-to-Point Connection................ 8-6
8.3 AT Site......................................................8-8
8.3.1 FlexNU...............................................................8-8
8.3.2 RAU...................................................................8-9
8.3.3 Antenna.............................................................8-9
8.4 Core ATM – C-AAS (CE Shelf)................8-10
8.4.1 Front Access Shelf ..........................................8-10
8.4.2 Rear Access Shelf...........................................8-11
8.4.3 POU.................................................................8-12
8.4.4 Fan Unit for Front Access AAS........................8-12
8.4.5 Fan Unit for Rear Access AAS........................8-13
8.5 Control and Management........................8-14
8.5.1 EM...................................................................8-14
8.5.2 CP ...................................................................8-15
8.6 PDU........................................................8-15
8.7 Cabinets/Racks.......................................8-16
8.7.1 Front Access Central Office.............................8-16
8.7.2 Rear Access Central Office.............................8-20
MINI-LINK BAS 8
Technical Description EN/LZB 111 0542 P2B
9 O&M Facilities......................... 9-1
9.1 Introduction...............................................9-2
9.1.1 Communication Channels.................................9-2
9.1.2 AT Setup...........................................................9-3
9.2 Fault Detection..........................................9-3
9.2.1 Alarms...............................................................9-3
9.2.2 Events...............................................................9-8
9.3 Test Loops................................................9-9
9.3.1 RN Near-End Loops..........................................9-9
9.3.2 AT Near-End Loops ..........................................9-9
9.3.3 AT Far-End Loops...........................................9-10
9.4 Performance Monitoring..........................9-11
9.4.1 Signals Monitoring...........................................9-12
9.5 Unit Replacement...................................9-12
9.6 Local Supervision Interface.....................9-13
9.7 System Upgrade.....................................9-16
9.7.1 Install SW Upgrade File...................................9-17
9.7.2 Download Modules..........................................9-17
9.7.3 Install New Management System....................9-17
9.7.4 Stop CP...........................................................9-17
9.7.5 Install New CP Software..................................9-17
9.7.6 Upgrade Network Database............................9-17
9.7.7 Start Control Processor in “Upgrade mode”....9-18
9.7.8 Execute Upgrade ............................................9-18
9.7.9 Restart Control Processor...............................9-19
9.7.10 Software Rollback...........................................9-19
9.7.10.1 Case A ..............................................................9-19
9.7.10.2 Case B ..............................................................9-20
9.7.10.3 Case C..............................................................9-20
10 Technical Data ...................... 10-1
10.1 System Parameters ................................10-2
10.1.1 Frequency Range............................................10-2
10.1.2 Transmitter Performance.................................10-4
10.1.3 Receiver Performance ....................................10-6
10.1.4 Transmission Technology...............................10-7
10.2 Intermediate Frequency..........................10-8
10.3 System Features.....................................10-9
10.4 Power Supply........................................10-11
10.5 Antenna Data........................................10-12
10.5.1 Radio Node Antennas...................................10-12
10.5.2 AT Antennas .................................................10-13
10.6 Environmental Requirements................10-14
10.6.1 Cabinets/Racks/Frames................................10-14
10.6.2 Power Distribution.........................................10-14
9 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
10.6.3 EMC ..............................................................10-14
10.6.4 Alarms...........................................................10-14
10.7 Characteristics ......................................10-15
10.7.1 Central Office.................................................10-15
10.7.2 AT..................................................................10-16
10.7.3 ODU ..............................................................10-17
10.8 Miscellaneous Features........................10-20
11 Index.......................................11-1
11.1 Index.......................................................11-2
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Technical Description EN/LZB 111 0542 P2B
1-1 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
Introduction
MINI-LINK BAS 1-2
Technical Description EN/LZB 111 0542 P2B
1.1 General Information
The new fields for application of microwave radio links introduce
more demanding functional requirements as well as stricter
requirements on operational performance. The transmission quality in
terms of acceptable bit error ratio, availability, and so on is improved,
as well as the spectral characteristics in order to permit effective
utilization of the available bandwidth.
The scope of requirements in the form of directives, standards and
recommendations issued by national and international organizations is
constantly widening.
The MINI-LINK BAS meets these requirements. Performance data
meets or surpasses the detailed requirements specified for this type of
equipment.
1.2 Manual Structure
The Technical Description was prepared in order to satisfy the
customer’s need for information on the technical features of his
equipment; it is composed of the following parts:
Contents
It includes the general contents of the chapters.
Introduction
It consists of this section that describes in short the contents of the
various parts composing the description and the list of acronyms and
abbreviations.
Chapters
They supply all information necessary to understand equipment
operation and technical characteristics. These are addressed to the
network planner and operation personnel who will find the
information they are interested in.
1-3 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
1.3 General Overview
The MINI-LINK BAS -Broadband Access System- product family is
member of Ericsson’s large and powerful product line for
telecommunication. The combined expertise of Ericsson, covering
switching, cellular technology, radio and networking, means
excellence in turnkey project management.
It is more than just an Asynchronous Transfer Mode (ATM) crossconnect featured by a point-to-multipoint microwave radio. It is a
complete system, including hardware, software, experience and
competence. The MINI-LINK BAS integrates fully with existing
telecom access networks, adding new levels of flexibility. It has
proved to be a reliable communication medium, a highly competitive
alternative to copper and fibre cable.
The MINI-LINK BAS is a natural step in Ericsson's product
development program, in response to new requirements from a
growing market and is based on more than 20 years’ experience of
microwave links.
Ericsson designers and engineers remain vigilant, seeking new
technology and developments to keep MINI-LINK BAS at the
forefront of microwave communications. Advanced Technology,
constant product development of powerful functions, operational
reliability and quality have resulted in the MINI-LINK BAS.
MINI-LINK BAS is a product for point-to-multipoint and point-topoint connections, carrying multimedia traffic services and is designed
primarily to meet increased demands for more efficient transmission
systems in access networks.
1.3.1 Opportunities
The worldwide deregulation of the local loop market, the emergence
of new wireless technologies, and an increased demand for new
services, has created a great market opportunity for existing and new
competitive access service providers.
Small and medium sized businesses have an increasing demand for
data oriented services such as high-speed Internet/Intranet access,
LAN-LAN interconnect, Internet Protocol (IP) services and T1/E1
leased line connections.
MINI-LINK BAS offers the possibility to satisfy these needs,
providing the medium for convergence between telecommunication,
and datacom/ Information Technology (IT) systems.
Ericsson experience in building world class radio products coupled
with clear market drivers such as Local Multipoint Distribution
System (LMDS), has lead Ericsson to define and develop our next
generation ATM based digital microwave radio systems, for
broadband radio access. The system is initially targeted for the
business community supporting a large range of multimedia services.
MINI-LINK BAS 1-4
Technical Description EN/LZB 111 0542 P2B
A well designed wireless broadband access system, enables operators
to provide rapid, cost efficient, flexible and reliable broadband access,
without the need of a cost prohibitive and complex fiber access
infrastructure. The system is efficient in both areas with high and
low/medium penetration since the system is featured by a scaleable
“pay as you grow” architecture.
IP
Services
Telephony
ATM
Leased
Line
Radio
Nodes
Access
Termination
Ethernet
and/or
E1/T1
interfaces
Indoor
Indoor
Indoor
Indoor
Indoor
Indoor
HUB
Outdoor
Outdoor
Figure 1-1 General Applications for the BAS
1.3.2 Product Benefits
The MINI-LINK BAS offers, to name a few, the following features:
• true Fast Dynamic Capacity Allocation (F-DCA) for data
services;
• port-to-port, intra-Hub, Local Area Network (LAN) and Private
Branch Exchange (PBX) interconnections without the use of core
resources;
• symmetrical broadband air-interface, independent in both
directions;
• cost-efficient scaleable broadband access solutions (pay as you
grow);
• rapid deployment and provisioning;
• reduced dependence on existing facilities;
• integration/convergence of different types of services such as IP
traffic and telephony traffic.
The radio design is based on the same platform that is being
developed for the immensely successful and reliable MINI-LINK
family, deployed in more than 100 countries.
1-5 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
This digital microwave family has shown exceptional reliability with
actual Mean Time Between Failures (MTBF) figures exceeding 30
years, thanks to a quality oriented high volume production, with a
current production capacity exceeding 100,000 units per year. In the
MINI-LINK BAS the new multi-chip module improves the reliability
and simplifies production even further.
• The design is compact and integrated. The radio and antenna
form an integrated outdoor part;
• clean-cut concept; the outdoor part holds all frequency-dependent
units and the indoor part holds all traffic management units;
• single coaxial cable interconnection between outdoor and indoor
parts;
• software-aided Access Terminal (AT) configuration and setup;
• centralized operation and maintenance system by means of the
EM (Element Manager);
• high system gain and spectrum utilization with an advanced
modulation process and coding;
• high MTBF figures of 20–30 years.
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Technical Description EN/LZB 111 0542 P2B
1.4 Terminology
AAL ATM Adaptation Layer
ACT AT Craft Tool
ANSI American National Standards Institute
API Application Programming Interface
ASK Amplitude Shift Keying
AT Access Terminal
AT Access Termination
ATM Asynchronous Transfer Mode
ATPC Automatic Transmit Power Control
BAS Broadband Access System
BBER Background Block Error Ratio
C-AAS Concentration Shelf
CB Channel Bank
CBR Constant Bit Rate
CE Circuit Emulation
CE-AAS Circuit Emulation Shelf
CE Board Network side Circuit Emulation card
CEPT Conference on European Post and Telegraph
CP Control Processor
CPE Customer Premise Equipment
C-QPSK Constant envelope offset Quadrature Phase
Shift Keying
CRC Cyclic Redundancy Check
DP Device Processor
EBER Excessive Bit Error Ratio
EIA Electronic Industries Association
EM Element Manager
ESR Error Second Ratio
ET Exchange Terminal
ETSI European Telecommunication Standard
Institute
FAS Frame Alignment Signal
1-7 MINI-LINK BAS
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FAW Frame Alignment Word
FEC Forward Error Correction
FCC Federal Communication Commission
FCS Frame Checking Sequence
F-DCA Fast Dynamic Capacity Allocation
FDD Frequency Division Duplex
FlexNU Flexible Network Unit
FPROM Flash Programmable Read Only Memory
GUI Graphical User Interface
HH Hardware Handler
HP-OV Hewlett Packard OpenView
HTTP Hyper Text Transport Protocol
ICS Internal Communication System
IEC International Electrotechnical Commission
IF Intermediate Frequency
IP Internet Protocol
IRCC Internally Radio Communication Channel
ISDN Integrated Services Digital Network
ISP Internet Service Provider
IT Information Technology
ITU International Telecommunications Union
LAN Local Area Network
LLC Logical Link Control
LMDS Local Multipoint Distribution System
LOS Line-of-Sight
MAC Media Access Control
MCM Multi-Chip Module
MIB Managed Information Base
MMIC Microwave Monolithic Integrated Circuit
MRI Managed Resource Interface
MRS Managed Resource Server
MS Management System
MTBF Mean Time Between Failures
MINI-LINK BAS 1-8
Technical Description EN/LZB 111 0542 P2B
NCU Node Control Unit
NE Network Element
NNM Network Node Manager
NU Network Unit
ODU Outdoor Unit
OTP Open Telecom Platform
OSI Open Systems Interconnection
PABX Private Automatic Branch Exchange
PBA Printed Board Assembly
PBX Private Branch Exchange
PDH Plesiochronous Digital Hierarchy
PDU Power Distribution Unit
PID Process Identification Number
PLL Phase Locked Loop
PMP Point to Multi Point
POTS Plain Old Telephone Service
POU Power Unit
PRC Primary Reference Clock
PSTN Public Switching Telephone Network
PSU Power Supply Unit
PVC Permanent Virtual Circuit
QoS Quality of Service
R-AAS Radio Shelf (Radio ATM Access Subrack)
RAI Remote Alarm Indication
RC Radio Control channel
RCL Radio Control Loop
RDI Remote Defect Indication
RF Radio Frequency
RN Radio Node
RAU Radio Unit
RSSI Received Signal Strength Indication
RTD Round Trip Delay
SC Service Configuration
1-9 MINI-LINK BAS
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SDH Synchronous Digital Hierarchy
SESR Severely Error Second Ratio
SN System Node
SNI Service Network Interface
SONET Synchronous Optical Network
STA Spanning Tree Algorithm
SU Service Unit (AT side)
TDM Time Division Multiplex
TDMA Time Division Multiple Access
TMN Telecommunication Management Network
UAT Unavailability
UBR Unspecified Bit Rate
UDT Unstructured Data Transfer
UF Uplink Efficiency
UNI User Network Interface
VC Virtual Channel
VCO Voltage Control Oscillator
VCTCXO Voltage Controlled Temperature Compesated
Crystal Oscillator
VoIP Voice over Internet Protocol
VP Virtual Path
WAN Wide Area Network
WBAS Wireless Broadband Access System
MINI-LINK BAS 1-10
Technical Description EN/LZB 111 0542 P2B
2-1 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
System Description
MINI-LINK BAS 2-2
Technical Description EN/LZB 111 0542 P2B
2.1 Overview
The MINI-LINK BAS integrates ATM transport and microwave
broadband technologies. This permits the system to efficiently use the
carrier bandwidth to support a wide range of medium to high-speed
services. It is a complete end-to-end solution from customer service
terminals, to IP/ATM/PSTN backbone equipment and management
systems. It assures the quality, availability and security that Ericsson
customers have come to depend on for over a century.
The MINI-LINK BAS consists of customer located Access
Terminations (ATs), communicating with Radio Nodes (RNs).
User traffic is either transported to the customer premises through a
dedicated point-to-point connection, for longer radio reach, or in a
point-to-multipoint configuration. The latter provides an efficient use
of available spectrum sharing the air interface capacity among many
customers and allowing the use of statistical multiplexing over the
radio interface.
The system communicates with ATM and PSTN backbones via a
variety of standard interfaces, from E1/T1 to OC-3/STM-1, 155 Mbps.
ATs support a wide variety of services, from PBX interconnections to
LAN to LAN interconnect and Internet access over different types of
interfaces such as E1/T1 and Ethernet 10/100BaseT.
The customer located ATs are designed with “hot plug-in” service
interface boards for different service requirements. So new services
are easily added without any impact on other services. ATs are also
designed with remote program capability so that settings can be
changed without the need for a visit from a service engineer at the
customer premises.
The MINI-LINK BAS utilises a Constant envelope offset-Quadrature
Phase Shift Keying/Time Division Multiple Access/Frequency
Division Duplex (C-QPSK/TDMA/FDD) scheme.
C-QPSK is a robust modulation scheme that delivers exceptional
Carrier to Interference (C/I) performance and a healthy link budget
that is required in a fully built out system.
The TDM/TDMA solution allows to efficiently support the fast
dynamics in bursty packet switched data networks (IP traffic) via
statistical multiplexing and F-DCA. This results in a very compact and
cost effective solution.
The MINI-LINK BAS uses applicable frequency spectrum such as:
• 24.5-26.5 GHz band in Europe
• 27.5-28.35 GHz in the US LMDS “A” band
• 31.0-31.30 GHz in the US LMDS “B” band
2-3 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
MINI-LINK BAS supports 28 MHz Channelling achieving a capacity
over the air interface of 37.5 Mbps in both directions.
The MINI-LINK BAS follows a cellular deployment structure where
multiple cells support a footprint over a geographical area. Each cell is
comprised of a Hub with multiple RNs equipped with
sector/directional antennas for point-to-multipoint and point-to-point
connections.
The ATs require a Line-of-Sight (LOS) path toward the Hub and can
be located anywhere within the sector coverage area, typically up to 6
km for point-to-multipoint access; up to 10 km for point-to-point
access; the actual distance depends on the operating frequency and
rain zone.
MINI-LINK BAS 2-4
Technical Description EN/LZB 111 0542 P2B
2.2 System Components
The MINI-LINK BAS consists of the following components:
1. AT
− In Door Unit (IDU): FlexNU
− Out Door Unit (ODU): Radio and antenna
2. RNs
− Indoor NCU
− ODU: Radio and antenna
3. C-AAS
4. Control and management
− CP
− EM
RNs are housed in R-AAS. A Radio Hub site can contain one or more
RNs plugged into one or more R-AASs. The multiple shelves can be
co-located or remote from each other.
EM
CP
ATM
Backbone
Server
Nodes &
Router
Element Manager Service
Configuration, Fault and
Perfomance Management
C-AAS
(CE Shelf)
R-AAS
FlexNU
ATs
FlexNU
Figure 2-1 MINI-LINK BAS Generic Network
2-5 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
2.2.1 AT
AT is composed by:
− IDU: FlexNU
− ODU: Radio and the antenna
AT is located at the edge of the network close to the subscriber
providing an interface between the MINI-LINK BAS network and the
subscriber equipment.
Each AT is assigned to a RN and receives downlink, broadcast traffic
from that RN using the TDM scheme. AT transmits uplink traffic to
the RN in a TDMA fashion sharing the total RN capacity, 37.5 Mbps,
with the ATs.
Network Unit (NU)
Service
Interface
Units
Modem
Unit
User
Radio
Unit
User
Antenna
Figure 2-2 AT Block Diagram
CE_NU_E1/T1, SU Ethernet
Modem Board
Ethernet
POTS
PABX
FlexNU
User Radio Unit
Figure 2-3 AT
MINI-LINK BAS 2-6
Technical Description EN/LZB 111 0542 P2B
2.2.1.1 FlexNU
FlexNU is the indoor part of the AT. It is connected to the ODU with
an IF coaxial cable, as shown in the Figure 2-3.
The FlexNU, which can house Modem board and Service Units (SUs),
features an active backplane on which the Media Access Control
(MAC) functionality is implemented.
FlexNU supports different types of services at each subscriber node by
means of SU boards. Two types of SUs are currently available:
• CE-SU E1/T1 with 2 interfaces per board
• 10/100BaseT-SU with 2 interfaces per board
Up to four SUs can be inserted as plug-in modules in the FlexNU.
This gives the FlexNU service flexibility and upgrade capability. In
addition to the plug-in SUs, the FlexNU is equipped with a power
supply unit, 110/220 Vac, and a built-in Ethernet 10BaseT interface
usable for maintenance operations.
2.2.1.2 ODU
The ODU consists of a Radio and a directional antenna ”Low Profile”
parabolic type, 0.20 m., integrated within its casing.
Optionally an integrated 0.60 m antenna is available.
2.2.1.3 ACT
The AT Craft Tool (ACT) is a software application that resides in the
AT. By means of an external notebook, working in VT-100 emulation,
the ACT is used for local maintenance of the AT. The connectivity is
provided by a RS232 interface available on the FlexNU front plate.
The installation or maintenance personnel can read or set configurable
parameters locally within the AT, for example the radio frequency, the
AT and RN identification numbers.
Via ACT it is possible to execute local software download and
download swap command can be independently executed.
2.2.2 RN
The Radio Node (RN) consists of an ODU and an IDU. The ODU is
made of a Radio and a Node Antenna. The Node Antenna is either a
directional antenna for point-to-point applications or a sector antenna
for point-to-multipoint applications.
2-7 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
A RN, equipped with a sector antenna, creates a sector carrier that
typically covers an area up to 6 km in radius. Multiple sector carriers
can be used to increase the capacity within a sector and multiple
sectors can be used to cover a complete cell area of a Radio Hub.
Node
Control
Unit
Node
Radio
Unit
Node
Antenna
Radio Node (RN)
=
Node
Control
Unit
MAC
+
Modem
Figure 2-4 RN Block Diagram
The Node Antenna and the Radio are encased in a weatherproof
outdoor mounted casing. The Radio is highly integrated and connected
to the IDU via an Intermediate Frequency (IF) coaxial cable.
The microwave parts incorporate Ericsson’s unique Microwave
Monolithic Integrated Circuit (MMIC) technology that supports
integration of a complete receiver and transmitter into a single multichip module, thus reducing the size of the ODU (see Figure 2-5).
MMIC technology also guarantees extremely high reliability and is
suitable for high-volume production.
The IDU is the NCU of the RN and it consists of Modem and MAC
board sandwiched in a single plug-in unit.
The Modem board provides the IF interface towards the outdoor
mounted radio and contains all modulating/demodulating functions.
The Modem is also in charge to maintain the radio links, providing
control loops for frequency, timing and transmitter power.
MAC functionality rules the traffic demands toward and from the
ATs. MAC is based on very fast protocol and scheduling mechanism
that grant capacity request in less than 1 msec.
The F-DCA feature of the MAC protocol affords very high statistical
gain so that Radio capacity is used in a very efficient way.
The MAC board connects to the ATM bus on the backplane of the RAAS.
The downering cell rate managed by a RN is 78000 cells/s. This is a
net capacity in downlink and a gross capacity in the uplink.
In order to calculate the net capacity in uplink it must consider the
overhead, which is necessary to handle traffic queues status in each
AT. The overhead depends on the number of ATs per RN and on the
polling period.
In the following table the capacity reduction is given for a defaultpolling period, 80 slots, versus the number of ATs per RN. The
Uplink Efficiency (UF) varies from 0.96 to 0.75.
The throughput at the application level, both CE and Ethernet will
decrease because of the ATM and AAL1, AAL5 overhead.
MINI-LINK BAS 2-8
Technical Description EN/LZB 111 0542 P2B
Moreover some capacity is allocated for control purpose and Physical
Layer preservation. In the table are reported the max number of
unstructured E1/T1 connections versus the number of ATs.
ATs/RN UF (%) E1/RN T1/RN
1 to 8 0.96 14 18
9 to 16 0.93 13 18
17 to 24 0.90 13 18
25 to 32 0.87 13 17
33 to 40 0.84 13 17
41 to 48 0.81 12 17
49 to 56 0.78 12 16
57 to 64 0.75 12 16
2.2.2.1 R-AAS
The R-AAS is an indoor mounted subrack that can accommodate up
to six plug-in NCUs (Modem + MAC). Each NCU is connected to an
ODU, which is dedicated to a RN in a sector.
R-AAS can also house ET and CE-SNI boards. ET boards provide
Wide Area Network (WAN) connectivity towards ATM backbone, IP
router, C-AAS. CE-SNI boards provide connectivity towards PSTN.
R-AAS provides a total of 17 board slots, which are distributed
according to the following scheme.
• Slot 1: ET board, any type 155, 45 or 34 Mbps
An ET board shall be always present for Cellbus
arbitration.
• Slot 2, 3: 2 CE-boards
• Slot 4, 5: 1 NCU or 2 CE-boards
• Slot 6, 7: 1 NCU or 2 CE-boards
• Slot 8, 9: 1 NCU or 2 CE-boards
• Slot 10, 11: 1 NCU
• Slot 12, 13: 1 NCU
• Slot 14, 15: 1 NCU
• Slot 16: POU
• Slot 17: POU
Depending on the configuration, a R-AAS can host up to 6 RNs, or up
to 8 CE-boards that can terminate 32 E1/T1 interface connections.
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