Nortel Networks 411-2021-111 User Manual

411-2021-111

Wireless Networks

DualMode Metrocell

Cell Site Description

411-2021-111 Standard 01.01 June 1996



Wireless Networks

DualMode Metrocell

Cell Site Description

Product release: DualMode Metrocell
Document release: Standard 01.01
Date: June 1996
Document Number: 411-2021-111

Copyright Country of printing Confidentiality Legal statements Trademarks

1996 Northern Telecom

Printed in the United States of America

NORTHERN TELECOM CONFIDENTIAL:

Telecom. Except as specifically authorized in writing by Northern Telecom, the holder of this document shall keep the information
contained herein confidential and shall protect same in whole or in part from disclosure and dissemination to third parties and use
same for evaluation, operation, and maintenance purposes only.

Information is subject to change without notice.

DMS, DMS SuperNode, DMS-MSC, DMS-HLR, DMS-100, and MAP are trademarks of Northern Telecom.

The information contained in this document is the property of Northern

iv

Publication history

June 1996

Standard 01.01 Initial release of document.

411-2021-111 Standard 01.01 June 1996

v

Contents

Publication history iv
About this document ix

Intended audience for this publication ix
How this publication is organized x
Applicability of this publication x

List of terms xi
Introduction 1-1

Northern Telecom's DualMode Metrocell 1-1
The 800 MHz cellular band 1-4

Cell Site Configurations 2-1

Overview 2-1
Omni configuration 2-1
120 ° sectorized configuration 2-2
60 ° sectorized configuration 2-4

Cell Site Layouts 3-1

Omni cell site configuration 3-1

Control Channel redundancy 3-2
Transmit cabling 3-5
Receive cabling 3-7
Component requirement 3-7

120 ° STSR cell site configuration 3-8

Control Channel redundancy 3-8
Transmit cabling 3-12
Receive cabling 3-17
Component requirement 3-20

60 ° STSR cell site connection 3-21

Control Channel redundancy 3-21
Transmit cabling 3-27
Receive cabling 3-33
Component requirement 3-37

DMS-MTX DualMode Metrocell Cell Site Description

vi

Contents

Cell Site Components 4-1

Customer Service Operations 4-3

Power and Grounding Requirements 5-1

Safety requirements 5-1
Power and grounding requirements 5-2

Frame power distribution 5-5
System power protection 5-6
Grounding 5-6

Cable Identification 5-9

Datafilling a Metro Cell Site 6-1

Datafill Overview 6-1

Table CLLI 6-2
Table ACUALM 6-2
Table VCHINV, CCHINV, LCRINV 6-5

Appendices

Appendix A: DualMode Metrocell Cell Site Specifications 7-1

System Configuration 7-1
Radio Frequency 7-1
Audio Interface 7-2
Alarms 7-2
DC Power Requirements 7-3
Power Distribution Requirements 7-3
Mechanical 7-3
Packaging 7-4
Environmental 7-4
Regulatory 7-5

Appendix B: Frequency plans 7-7

N=7 Frequency plan (Band A) 7-7
N=7 Frequency plan (Band B) 7-8
N=4 Frequency plan (Band A) 7-9
N=4 Frequency plan (Band B) 7-9

List of figures

Figure 1-1 System architecture of a DualMode Metrocell 1-2
Figure 1-2 Digital ready cellular product 1-2
Figure 1-3 Basic components of a DualMode Metrocell 1-3
Figure 1-4 Channel assignment for 800 MHz cellular systems 1-4
Figure 2-1 Omni (N=7) frequency reuse plan 2-2
Figure 2-2 120 ° (N=7) sectorized frequency reuse plan 2-3
Figure 2-3 60 ° (N=4) sectorized frequency reuse plan 2-4
Figure 3-1 Frame layout of an omni Metrocell with one RF frame (front view) 3-

2

Figure 3-2 Block diagram of an omni Metrocell with up to 20 channels in one

RF Frame 3-3

Figure 3-3 Block diagram of an omni Metrocell with 21 to 24 channels in one

RF Frame 3-4

411-2021-111 Standard 01.01 June 1996

Contents vii

Figure 3-4 Frame layout of a 120 ° STSR Metrocell site with one RF frame

(front view) 3-9

Figure 3-5 Frame layout of a 120 ° STSR Metrocell site with three RF frames

(front view) 3-9
Figure 3-6 Block diagram of a 120 ° STSR Metrocell using one RF Frame 3-10
Figure 3-7 Block diagram of a 120 ° STSR Metrocell using three RF Frames 3-

11
Figure 3-8 Frame layout of a 60 ° STSR Metrocell with two RF frames (front

view) 3-22
Figure 3-9 Typical frame layout of a 60 ° STSR Metrocell with four RF frames

(front view) 3-22
Figure 3-10 Block diagram of a 60 ° STSR Metrocell with two RF Frames 3-23
Figure 3-11 Block diagram of a 60 ° STSR Metrocell with four RF Frames 3-25
Figure 5-1 Power distribution for the CE and RF Frames in a Metrocell 5-5
Figure 6-1 Example of Metro TRU datafill 6-6
Figure 6-2 Example of Metro ICRM/TRU hardwire configuration 6-7

List of tables

Table 1-1 Channel designation and frequency assignment 1-5
Table 3-1 RF Frame 1 PA to ATC connection for an omni Metrocell with up to

20 channels 3-5
Table 3-2 RF Frame 1 PA to ATC connection for an omni Metrocell with 21

channels or more 3-6
Table 3-3 RMC to splitter connections for an Omni Metrocell 3-7
Table 3-4 Component requirement for an omni Metrocell 3-7
Table 3-5 PA to ATC connection for a 120 ° Metrocell with one RF Frame 3-12
Table 3-6 PA to ATC connection for a 120 ° Metrocell with 20 channels or less

per RF frame for one sector 3-13
Table 3-7 PA to ATC connection for a 120 ° Metrocell with 21 channels or

more per RF frame for one sector 3-15
Table 3-8 RMC to splitter connections for a 120 ° STSR Metrocell with one RF

Frame 3-17
Table 3-9 RMC to splitter connections for a 120 ° STSR Metrocell with three

RF Frames 3-18
Table 3-10 Component requirement for a 120 ° STSR Metrocell with one RF

Frame 3-20
Table 3-11 Component requirement for a 120 ° STSR Metrocell with three RF

Frames 3-20
Table 3-12 PA to ATC connection for a 60 ° STSR Metrocell using two RF

Frames 3-28
Table 3-13 PA to ATC connection for a 60 ° STSR Metrocell using four RF

Frames 3-30
Table 3-14 RMC to splitter connections for a 60 ° STSR Metrocell with two RF

Frames 3-33
Table 3-15 RMC to splitter connections for a 60 ° STSR Metrocell with four RF

Frames 3-34
Table 3-16 Component requirement for a 60 ° STSR Metrocell with two RF

Frames 3-37
Table 3-17 Component requirement for a 60 ° STSR Metrocell with four RF

Frames 3-37

DMS-MTX DualMode Metrocell Cell Site Description

viii Contents

Table 4-1 Major components of a DualMode Metrocell 4-1
Table 5-1 Metrocell DC Power performance requirements 5-3
Table 5-2 Cable identification - North America 5-9
Table 6-1 Datafill differences of the Metrocell from an NT800DR cell 6-1
Table 6-2 Trunk requirement for different Metrocell configurations 6-2
Table 6-3 MTX Datafill Alarm Points for Metro RF Frame 6-3
Table 6-4 MTX Alarm Points Datafill Numbers for Metro RF Frame 6-4
Table 6-5 MTX Alarm Points Datafill Numbers for Metro CE Frame

components 6-4
Table 6-6 NT8X47BA Port Numbers for Metro TRU locations 6-5

411-2021-111 Standard 01.01 June 1996

ix

About this document

This publication is one of a set of documents that provide Northern Telecom
(Nortel) customers with information and suggestions on the planning and
maintenance of their DualMode Metrocell system. This set of documents
includes the following manuals:

• DualMode Metrocell Functional Description Manual

— DualMode Metrocell Cell Site Description
— DualMode Metrocell Common Equipment (CE) Frame Description
— DualMode Metrocell Radio Frequency (RF) Frame Description

• DualMode Metrocell Planning and Engineering Guidelines

• DualMode Metrocell Installation Manual

• DualMode Metrocell Operation and Maintenance Manual

• DualMode Metrocell Troubleshooting Guidelines

The manual suite for the DualMode Metrocell provides information on cell
site configurations, hardware components, planning and installation
procedures, as well as maintenance and troubleshooting methods.

Intended audience for this publication

The intended audience for this set of manuals is the cell site technicians and
the planning engineers who require information in the maintenance and
planning of a DualMode Metrocell. The Functional Description Manual
provides a technical reference foundation for the other documents in the
documentation suite and is written for all.

The Planning and Engineering Guidelines is written for system planning
personnel in implementing new cells or expanding existing cell sites in a
cellular system.

The Operation and Maintenance Manual and the Troubleshooting Guidelines
that provide information on problem recognition and preventive maintenance
are written for cell site technicians to assist them in troubleshooting and
performing their routine work.

DMS-MTX DualMode Metrocell Cell Site Description

x

About this document

The document suite assumes that the reader possesses a basic knowledge of
the cellular system and radio propagation and is familiar with measurement
units incorporated in the system. Therefore, this document will not provide
detailed information on the theory of switching and radio propagation.

How this publication is organized

This publication is organized to present the following information:

• an introduction to the DualMode Metrocell Cell Site

• the Metrocell cell site configurations; omni, 120 ° STSR and 60 ° STSR

• the equipment layouts, block diagrams and transmit and receive cabling

for each configuration

• the cell site components required for each configuration

• the power and grounding requirements for a Metrocell cell site

• information on datafilling a Metrocell.

Applicability of this publication

This publication is generically applicable to MTX01 feature functionality, yet
captures some BCS-independent environment and implementation issues.

411-2021-111 Standard 01.01 June 1996

xi

List of terms

A-Band

The lower 333 channels (Channel 1 - 333) of the cellular band, normally assigned
to a non-wireline operator in the US and Canada.
The Expanded Spectrum provides 83 more channels, 50 (Channel 667 - 716) in
the A’-Band and 33 (channel 991 - 1023) in the A"-Band.

ACU

AMPS

ATC

B-Band

BER

Carrier (RF)

Alarm Control Unit. A unit that provides discrete alarm monitoring, reporting and
control functions at the cell site. It concentrates all alarm input points at the cell
site and updates the MTX of any status change over redundant data links.

Advanced Mobile Phone Service. Analog cellular phone service.

AutoTune Combiner. A cavity/isolator combiner featuring an automatic tuning
system which monitors the transmitted RF and automatically tunes itself to that
frequency.

The upper 333 channels (Channel 334 - 666) of the cellular band, normally
assigned to a wireline operator in the US and Canada.
The Expanded Spectrum provides 83 more channels (Channel 717 - 799) in the
B’-Band.

Bit Error Rate. The ratio of error bits to the total number of transmitted bits. It is
a measurement of quality of the digital connection.

An unmodulated radio signal. Normally, it is a pure sine wave of steady
frequency, amplitude, and phase.

CCH

Control Channel, sometimes referred to as the Signaling Channel which is always
in use to enable call setup and registration.

DMS-MTX DualMode Metrocell Cell Site Description

xii List of terms

Cell

CSM2

dBm

dBW

DCC

ES

By theoretical design, it is the geographical representation of the cellular
coverage area or service area defining both the associated size and shape.

Cell Site Monitor 2. A unit that provides analog testing and monitoring
capabilities at the cell site.

Decibels above a milliwatt. Unit of power measurement popular in wireless
telephony, general telephony, audio, and microwave.

Decibels above a watt. Unit of measurement for radio power

Digital Color Code. An identifying code associated with the control channel of
the cellular base transmitter which is used to enhance call processing in the
cellular infrastructure.

DLR

DMS-MTX

DPA

DRUM

Duplexer

DVCC

Digital Locate Receiver. The TDMA equivalent of the Locating Channel
Receiver. See LCR.

The acronym for Nortel's family of cellular switches: Digital Multiplex Switch ­Mobile Transmission Exchange.

Dual Power Amplifier. A module which contains two discrete power amplifiers
that provide amplification of the RF signal for the two corresponding Transmit
Receive Units (TRU) on the same TRU/DPA shelf.

DualMode Radio Unit Monitor. A test and monitor unit capable of radio
communications with any Voice Channel of the local Transmit Receive Units
(TRU) in the digital mode.

A device that consists of two pass or pass/reject filters configured to provide a
common output port for both transmit and receive frequencies.

Digital Verification Color Code. The TDMA equivalent of DCC.

Expanded Spectrum. The additional frequency spectrum assigned to the cellular
band. The Expanded Spectrum in the A-Band consists of the A’-Band and the A"­Band while the B’-Band is the Expanded Spectrum for the B-Band. The
Expanded Spectrum provides a total of 416 channels to each of the two bands.

411-2021-111 Standard 01.01 June 1996

FDMA

Frequency Division Multiple Access. A frequency assignment arrangement
whereby all users share the total frequency allotment and each frequency is
assigned to a given user at access on a multiple user access basis.

Filter

A frequency selective device which is tuned to pass some frequencies and
attenuate others. Common filter types include high-pass, low pass, band-pass,
and notch filters

Frequency Modulation. A modulation technique that causes the frequency of the
carrier to vary above and below its resting frequency; the rate of which is
determined by the frequency of the modulating signal and the deviation of which
is determined by the magnitude of the modulating signal.

Forward path

The path from cell site to cellular subscriber.

IM

FM

List of terms xiii

HSMO

ICP

ICRM

Isolation

High Stability Master Oscillator. A unit that provides a highly stable 4.8 MHz
reference for synchronizing the Transmit Receive Unit (TRU).

Intelligent Cellular Peripheral. A switch site peripheral that provides an interface
between the cell site and the switch. The ICP also oversees the operations of the
cell site.

Integrated Cellular Remote Module. A cell site peripheral that serves as an
interface between the Intelligent Cellular Peripheral (ICP) and the radio
transmission subsystems. The ICRM is designed to support both analog and
digital Radio Frequency (RF) equipment.

Intermodulation. A type of interaction between signals in a nonlinear medium
which produces phantom signals at sum and difference frequencies. These
phantom signals may interfere with reception of legitimate signals occupying the
frequencies upon which they happen to fall.

The attenuation (expressed in dB) between any two signal or radiation points.

LCR

Loss

Locating Channel Receiver. A radio receiver which is frequency agile and is used
to measure and report the received signal strength, in dBm, of a channel.

A magnitude of attenuation, expressed in dB, for a given path between any two
points.

DMS-MTX DualMode Metrocell Cell Site Description

xiv List of terms

Modulation

NES

Omni

/4 DQPSK

RF

π

The process of placing information on an RF carrier. The modulation technique
may involve changing the amplitude, frequency, or phase of the carrier
determined by the modulation index.

Non-expanded Spectrum. The frequency spectrum initially assigned to the
cellular band. The Non-expanded Spectrum provides 333 channels to each of the
two bands, the A-Band and the B-Band.

An antenna design which permits radiation in essentially all H-Plane azimuths.
In cell sites, an Omni configuration means a single set of omni antennas is used
for all channels.

Variation of Differential Quadrature Phase Shift Keying used in D_AMPS IS-54
TDMA for improved spectral characteristics and phase resolution. Permissible
phase changes are integral multiples of π /4 radians (45 degrees). π /4 is used to
reduce the peak to root mean square ratio requirements for linear PAs.

Return loss

A logarithmic relationship of the incident signal to the reflected signal as
expressed, in dB, by the following relationship:

where Pi = incident power in watts

The strength of the signal, expressed in dB, reflected by a load back into a
transmission line due to impedance mismatch. -14 dB corresponds to a VSWR of

1.5:1.

Reverse path

The path from cellular subscriber terminal to cell site.

Radio Frequency. Electromagnetic energy of the frequency range just above the
audible frequencies and extending to visible light.

RIP

Rack Interface Panel. The RIP is the interface between the cell site power supply
and the cell site equipment.

Return Loss =

10 log

Pr = reflected power in watts

P

r

P

i

411-2021-111 Standard 01.01 June 1996

RMC

RSSI

SAT

SCC

List of terms xv

Receive Multicoupler. A device for amplifying the input received from a single
antenna and providing multiple outputs for a group of receivers.

Received Signal Strength Indicator. A measurement of the received RF signal
strength measured at the base station or the subscriber terminal. It is expressed in
dBm.

Supervisory Audio Tone. A tone of 5970, 6000, or 6030 Hz which modulates the
AMPS voice channel along with voice audio. It is generated by the cell site and
is repeated by the mobile back to the cell site. The repeated SAT is checked by
the cellular system to confirm the continuity of the complete RF path from the
cell site to the subscriber terminal and back to the cell site.

SAT Color Code. The datafill values corresponding to the various SATs: 00 for
5970 Hz, 01 for 6000 Hz, 10 for 6030 Hz.

Sector

A theoretical wedge-shaped part of the coverage area of one cell site, served by a
specific group of directional antennas on specific channels.

Sectorization

A cell site configuration that consists of two or more sectors in which a different
control and voice channel assignment is given for each sector. In this
arrangement, the datafill and channel assignments for each sector are tailored to
meet the system operational requirements, providing more flexibility in the cell
site configuration compared to an omni configuration but with a decrease in
trunking efficiency.

Signal (RF)

Radio frequency energy associated with a particular or desired frequency.

SINAD

A standard measurement of detected audio quality that is related to signal-to­noise plus distortion of the RF signal strength at the receiver input terminal. 12
dB SINAD is the commonly used threshold for receiver sensitivity measurements
to determine the weakest-practical analog RF input, in dBm, required by the
receiver. A SINAD of 20 dB is considered good quality and defines the RF input
level needed to fully quiet the receiver.

S/N

Signal-to-Noise ratio. The ratio of signal power to noise power on a radio
channel.

DMS-MTX DualMode Metrocell Cell Site Description

xvi List of terms

STSR

TDMA

TRU

ST

Signaling Tone. In AMPS cellular, a 10 kHz tone transmitted on the Reverse
Voice Channel (RVC) as a precursor to messaging activity, and for certain call­processing functions (acknowledgments, call termination). Presence of the tone
mutes normal conversational audio.

Sectored-Transmit/Sectored-Receive. A cell configuration in which a different
control and voice frequency assignment is designated for each sector. A
directional antenna system is required for each sector.

Time Division Multiple Access. A modulation and transmission format that
allows a number of digital conversations (three in TDMA-3) to occur within the
same Radio Frequency (RF) channel. Mobile units take turns transmitting/
receiving data on specific time slots of a TDMA frame.

Transmit Receive Unit. The TRU is a Digital Signal Processing (DSP) based
transceiver capable of two modes of operation, analog (AMPS) and digital
(TDMA).

VCH

VSWR

Voice Channel. A Radio Frequency (RF) channel used to transmit cellular voice
conversations. The VCH is also an integral part of call setup, handoff, and
disconnect.

Voltage Standing Wave Ratio. A measure of the mismatch between the
transmitter source impedance and the load impedance to which it is connected. It
is defined by the following relationship:

1 +

VSWR =

1 -

Reflected Power

Forward Power

Reflected Power

Forward Power

411-2021-111 Standard 01.01 June 1996

1-1

1

Introduction

Northern Telecom's DualMode Metrocell

As cellular systems evolve to the digital format, service providers and mobile
subscribers are confronted by a mixture of analog and digital technologies.
Northern Telecom (Nortel)’s dual mode cellular product allows a smooth
transition from analog to digital technology. It uses Time Division Multiple
Access (TDMA) technology for digital systems and Advanced Mobile Phone
Service (AMPS) technology for analog systems. This evolutionary strategy
enables service providers to gradually upgrade their cellular systems to digital
while providing support of existing analog equipment.

The Nortel cellular system supporting dual mode service includes the following
components:

• the DMS-MTX switch containing the Intelligent Cellular Peripheral (ICP)

unit at the mobile switching office

• dual mode cell sites with the configurable DualMode Radio Units (DRU)

on a Radio Frequency (RF) Frame and the Integrated Cellular Remote
Module (ICRM), on a Common Equipment (CE) Frame at the cell site

• external and internal interface links.

The Nortel DualMode Metrocell serves as the intelligent interface between a
Digital Multiplex Switch - Mobile Telephone Exchange (DMS-MTX) and its
registered cellular mobiles. It is a dual mode cell that works in both the analog
(AMPS) mode and the digital (TDMA) mode.

The Metrocell is designed for high density, small radius cells in areas where
large traffic capacity is required. It can exist independently or it can be added
to existing cells for increased coverage. The Metrocell provides a reduced
power output for urban applications. The typical power output of the Power
Amplifier (PA) is 22 watts (43.5 dBm).

Figure 1-1 shows the architecture of a DualMode Metrocell system and
Figure 1-2 is a block diagram of the product of the system.

DMS-MTX DualMode Metrocell Cell Site Description

1-2 Introduction

Figure 1-1
System architecture of a DualMode Metrocell

PSTN

Trunk

Figure 1-2
Digital ready cellular product

DMS-MTX

Digital Transmission

Facility

DualMode

Metrocell

DMS - MTX

ICP

SWITCH SITE

There are at least two equipment frames in a Metrocell, a Universal Common
Equipment (CE) Frame and a Metro Radio Frequency (RF) Frame. The cell
site can be expanded or sectorized by adding more Metro RF frames as traffic
grows. The number of Metro RF frames is determined by the cell site
configuration and the channel capacity. Figure 1-3 shows the frames and the
components of a DualMode Metrocell.

411-2021-111 Standard 01.01 June 1996

voice and
control

ICRM

voice &
control

control

CELL SITE

control

DRU

DRUM

CSM2

ACU

Figure 1-3
Basic components of a DualMode Metrocell

Universal CE Frame Metro RF Frame

Introduction 1-3

RIP

DRUM

ACU

HSMO

CSM2

Dual RMC
(one to six)

ICRM

Blank Panel

Base

Duplexer

(one to three)

TRU/DPA Shelf
(TRUs & DPAs)

TRU/DPA Shelf
(TRUs & DPAs)

TRU/DPA Shelf
(TRUs & DPAs)

Legend:
RIP Rack Interface Panel
DRUM DualMode Radio Unit Monitor
ACU Alarm Control Unit
HSMO High Stability Master Oscillator
CSM2 Cell Site Monitor 2
RMC Receive Multicoupler
ICRM Integrated Cellular Remote Module
ATC AutoTune Combiner
TRU Transmit Receive Unit
DPA Dual Power Amplifier

RIP

ATC

ATC

ATC

Base

DMS-MTX DualMode Metrocell Cell Site Description

1-4 Introduction

The 800 MHz cellular band

In an 800 MHz North American cellular system, a frequency spectrum of 50
MHz is available for service. Operating from 824 to 894 MHz, including the
expanded spectrum, the system conforms to the AMPS IS-54 protocol.
Typically this range is divided into 832 radio frequency (RF) channels. The 832
RF channels are divided into two bands, A and B. The two bands are identified
as follows:

• Band A—for Non-Wireline Operators

• Band B—for Wireline Operators.

Each frequency band has 416 RF channels. Of these 416 RF channels,
typically 21 (depending on the frequency plan) are assigned as the Control
Channels (CCH) and the remaining 395 are Voice Channels (VCH). See
Figure 1-4 and Table 1-1.

Figure 1-4
Channel assignment for 800 MHz cellular systems

Base Station Frequency (MHz)

824 825 835 835 846.5 849 851

RX

Band

869 870 880 890 891.5 894 896TX

A" A B A' B'

1

991

1023

Channel assignment Band A (416 channels) Band B (416 channels)

Control channels 313 - 333 (21) 334 - 354 (21)
Optional—TDMA secondary

control channels
Voice channels 001 - 312 (312)

A-Band CCH

B-Band CCH

333

Channel Number

688 - 708 (21) 737 - 757 (21)

667 - 716 (50)
991 - 1023 (33)

716 799

666

R=Reserved

355 - 666 (312)
717 - 799 (83)

R

411-2021-111 Standard 01.01 June 1996

Table 1-1
Channel designation and frequency assignment

Introduction 1-5

System Channel Cell site receive

frequency (MHz)

Not used 990 824.010 869.010

A" 991 - 1023 824.040 - 825.000 869.040 - 870.000

A 1 - 333 825.030 - 834.990 870.030 - 879.990
B 334 - 666 835.020 - 844.980 880.020 - 889.980
A’ 667 - 716 845.010 - 846.480 890.010 - 891.480

B’ 717 - 799 846.510 - 848.970 891.510 - 893.970

Cell site transmit

frequency (MHz)

The relationship between the channel number (N) and the frequency is:
Channel number: 1 ≤ N ≤ 799

Receiver frequency (in MHz) = 0.03N + 825.000
Transmit frequency (in MHz) = 0.03N +870.000

Channel number: 990 ≤ N ≤ 1023

Receiver frequency (in MHz) = 0.03(N - 1023) + 825.000
Transmit frequency (in MHz) = 0.03(N - 1023) + 870.000

Both non-expanded and expanded spectrums are shown in Appendix B for the
N=7 and N=4 frequency groups.

Important

For ALL Metrocell cell site configurations, the frequency

plan used should have a minimum of 21 channel spacing

(630 kHz) between the RF channels.

DMS-MTX DualMode Metrocell Cell Site Description

1-6 Introduction

411-2021-111 Standard 01.01 June 1996

2-1

2

Cell Site Configurations

Overview

The DualMode Metrocell can be configured in the following ways:

• Omni-directional transmit/receive

• 120 ° Sectored Transmit Sectored Receive (STSR)

• 60 ° Sectored Transmit Sectored Receive (STSR)

The majority of systems may begin as Omni-directional to minimize startup
costs. As the subscriber traffic increases, the Omni configuration may reach
its maximum traffic capacity. At that time it will be necessary to provide
additional capacity through expanded spectrum, 120 degree sectorization, 60
degree sectorization, or frequency borrowing.

It is important that the operator selects a frequency plan before the Omni
configuration is installed. If not, future expansions will be very difficult. The
most common frequency plans are:

• 7 Cell Cluster (N=7)—This frequency plan allows proper expansion from

Omni to 120 degree sectorization (see Figure 2-1 and Figure 2-2).

• 4 or 12 Cell Cluster (N=4 or N=12)—This frequency plan allows proper

expansion from Omni to 60 degree sectorization (see Figure 2-3).

Both non-expanded and expanded spectrums are shown in Appendix B for the
N=7 and N=4 frequency groups.

Omni configuration

In an Omni (N=7) configuration, the 416 RF channels are divided among a
group of seven cells (often known as a cluster). Each cell consists of a
maximum of 59 or 60 RF channels (four cells with 59 channels and three cells
with 60 channels, where three of the 59 or 60 channels are Control channels).
The RF channels are reused by other cell clusters. Frequency reuse refers to
the use of RF channels on the same carrier frequency in different areas which
are separated from one another by the greatest possible distance so that co­channel interference is minimized.

DMS-MTX DualMode Metrocell Cell Site Description

2-2 Cell Site Configurations

Figure 2-1 shows the layout of an Omni (N=7) frequency reuse plan;. The RF
channels used in Cell 1 of a cluster are reused in Cell 1 of other clusters,
channels in Cell 2 are reused in Cell 2 of other clusters and so on.

Figure 2-1
Omni (N=7) frequency reuse plan

CELL 6

CELL 7

CELL 2

CELL 7

CELL 1

CELL 2

CELL 6 CELL 3

CELL 5

CELL 1

CELL 4

CELL 3

CELL 7

CELL 2

CELL 5

CELL 4

CELL 6

CELL 5

CELL 1

CELL 4

CELL 3

120 ° sectorized configuration

In a 120 ° (N=7) sectorized configuration, the 416 RF channels are divided
among a cluster of seven cells. Each cell contains a maximum of 59 or 60 RF
channels, with three Control channels for each cell. Since each cell is further
divided into three sectors, each sector will contain a maximum of 19 or 20 RF
channels, with one Control channel for each sector. The available RF
channels are reused by other groups of cells within the system.

411-2021-111 Standard 01.01 June 1996

Figure 2-2 shows the layout of a 120 ° (N=7) sectorized frequency reuse plan.
The RF channels used in Cell 1 of a cluster are reused in Cell 1 of other
clusters, channels in Cell 2 are reused in Cell 2 of other clusters and so on.
This arrangement will have the RF channels using the same carrier frequency
in different areas to be separated from one another by the greatest possible
distance to minimize co-channel interference.

However, sectorization (by virtue of the modified coverage areas and
directional antenna usage) permits greater reuse of frequencies for a given
C/I ratio.

Figure 2-2
120 ° (N=7) sectorized frequency reuse plan

Sector

CELL 7

Z

Sector

CELL 2

Z

X

Y

Sector

CELL 5

Z

X

Y

Sector

CELL 4

Z

X

Y

Sector

Z

Sector

Z

Sector

X

CELL 7

Sector

Sector

CELL 2

Sector

Sector

Sector

CELL 6

Z

Sector

Sector

Y

Sector

CELL 1

Z

X

Y

Sector

Z

Sector

Sector

CELL 3

Sector

Sector

X

Sector

Y

Sector

X

Sector

Y

Sector

X

Sector

Y

Sector

X

Sector

Y

Sector

Z

Sector

Z

Sector

Z

Sector

Z

Sector

Z

Sector

X

CELL 6

Sector

Sector

X

CELL 1

Sector

Y

Sector

X

CELL 3

Sector

Sector

X

CELL 7

Sector

Sector

X

CELL 2

Sector

Cell Site Configurations 2-3

Sector

Y

Sector

Z

Sector

Z

Y

Sector

Z

Y

Sector

Z

Y

Sector

Z

X

CELL 5

Sector

Sector

X

CELL 4

Sector

Sector

X

CELL 6

Sector

Sector

X

CELL 1

Sector

Sector

CELL 3

Sector

Y

Y

Sector

Y

Sector

Z

Y

Sector

Z

X

Y

CELL 5

Sector

Sector

X

CELL 4

Sector

X

Y

Y

DMS-MTX DualMode Metrocell Cell Site Description

60 °

2-4 Cell Site Configurations

sectorized configuration

In a 60 ° (N=4) sectorized configuration, the 416 RF channels are divided
among a group of four cells. Each cell contains a maximum of 104 RF
channels, with six Control channels for each cell. Since each cell is further
divided into six sectors, each sector will contain a maximum of 16 or 17 RF
channels, with one Control channels for each sector. The RF channels are
reused by other groups of cells.

Figure 2-3 shows the layout of a 60 ° (N=4) sectorized frequency reuse plan.
The RF channels used in Cell 1 of a cluster are reused in Cell 1 of other
clusters, channels in Cell 2 are reused in Cell 2 of other clusters and so on.
This arrangement will have the RF channels on the same carrier frequency in
different areas to be separated from one another by the greatest possible
distance so that co-channel interference is minimized.

However, 60 ° sectorization is difficult to expand and optimize due to a more
demanding environment of frequency re-use.

Figure 2-3
60 ° (N=4) sectorized frequency reuse plan

Sector

X

CELL 1

Sector

U

Sector

X

CELL 3

Sector

U

Sector

X

CELL 1

Sector

U

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

W

Sector

V

Sector

X

CELL 1

Sector

U

Sector

Y

Sector

Z

Sector

W

Sector

V

Sector

W

Sector

V

Sector

X

CELL 2

Sector

U

Sector

X

CELL 4

Sector

U

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

W

Sector

V

Sector

W

Sector

V

Sector

W

Sector

V

Sector

W

Sector

V

Sector

W

Sector

V

Sector

W

Sector

V

Sector

W

Sector

V

Sector

X

CELL 2

Sector

U

Sector

X

CELL 4

Sector

U

Sector

X

CELL 2

Sector

U

Sector

X

CELL 4

Sector

U

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

W

Sector

V

Sector

W

Sector

V

Sector

W

Sector

V

Sector

X

CELL 3

Sector

U

Sector

X

CELL 1

Sector

U

Sector

X

CELL 3

Sector

U

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

W

Sector

V

Sector

W

Sector

V

Sector

X

CELL 2

Sector

U

Sector

X

CELL 4

Sector

U

Sector

Y

Sector

Z

Sector

Y

Sector

Z

Sector

W

Sector

V

Sector

X

CELL 3

Sector

U

Sector

Y

Sector

Z

411-2021-111 Standard 01.01 June 1996

3-1

3

Cell Site Layouts

This chapter provides information on the layout and cabling of the different
DualMode Metrocell configurations.

Important

For ALL Metrocell cell site configurations, the frequency
plan used should have a minimum of 21 channel spacing
(630 kHz) between the channels in one RF Frame.

Note: The DualMode Metrocell supports only Transmit Receive Units

(TRU) with Product Engineering Code (PEC) NTAX98AA. No other
radios can be used. The NTAX98AA TRU supports full digital and analog
transmissions in accordance with IS-54 and IS-41 standards.

Omni cell site configuration

The Metrocell in an omni configuration uses at least two equipment frames,
one CE Frame and one RF frame (see Figure 3-1). With only one RF frame,
the maximum number of Voice Channels (VCH) supported by the cell site is
22 since two of the 24 TRUs have to be assigned as the Control Channel
(CCH) and the Locate Channel Receiver (LCR). As traffic grows, four
additional RF frames can be added to the site to accommodate up to a
maximum of 120 channels, including the CCH and the LCR.

An RF Frame with up to 20 channels requires only one duplexer in the RF
Frame and one TX/RX antenna. The outputs of the three AutoTune
Combiners (ATC) are combined through one phasing transformer (located at
ATC 2) and then connected to Duplexer position 2. This configuration
requires a RX only antenna for the diversity receive function of the cell. See
Figure 3-2.

An RF Frame with 21 channels or more requires two duplexers in the RF
Frame and two TX/RX antennas. The outputs of the lower and middle ATCs

DMS-MTX DualMode Metrocell Cell Site Description

3-2 Cell Site Layouts

(ATC 1 and ATC 2) are combined through one phasing transformer (located at
ATC 2) and then connected to Duplexer position 2 and the main TX/RX
Antenna. The output of the upper ATC (ATC 3) is connected to Duplexer
position 3 and the diversity TX/RX Antenna. This arrangement is used to
meet the requirement of a minimum of 21 channel spacing (630 kHz)
between the channels in one RF Frame. This configuration requires a TX/RX
antenna to perform the diversity receive function of the cell. See Figure 3-3.

Control Channel redundancy

Control Channel (CCH) redundancy is commonly provided with a Locate
Channel Receiver (LCR) backup. The CCH is assigned to position 1 on the
TRU/DPA Shelf 1 and the LCR is assigned to position 4 on the same shelf.
This arrangement will have the CCH and the LCR supplied on a different DC
power feed and a TCM card. No RF coaxial switch is required since the
cavity of the LCR position on the ATC will tune to the CCH frequency when
backup is required.

Figure 3-1
Frame layout of an omni Metrocell with one RF frame (front view)

CE Frame RF Frame 1

CE RIP

DRUM

ACU

HSMO

CSM2

RMC 1

Blank Panel

ICRM

Blank Panel

Base

Duplexer

Position 3

TRU 21

TRU 17

TRU 13

TRU 9

TRU 5

TRU 1

RF RIP

Duplexer
Position 2

ATC 3

DPA11DPA

TRU 22

DPA9DPA

TRU 18

ATC 2

DPA7DPA

TRU 14

DPA5DPA

TRU 10

ATC 1

DPA3DPA

TRU 6

DPA1DPA

TRU 2

Base

12

10

8

6

4

2

Duplexer
Position 1

TRU 23

TRU 19

TRU 15

TRU 11

TRU 7

TRU 3

TRU/DPA

TRU 24

Shelf 3

TRU 20

TRU/DPA

TRU 16

Shelf 2

TRU 12

TRU/DPA

TRU 8

Shelf 1

TRU 4

Note: For a frame with up to 20 channels, only one duplexer (located in

position 2) is required.
For a frame with 21 channels or more, two duplexers (located in
positions 2 and 3) are required.

411-2021-111 Standard 01.01 June 1996

Figure 3-2
Block diagram of an omni Metrocell with up to 20 channels in one RF Frame

Cell Site Layouts 3-3

Control Channel

(Note 2)

ATC 1

PA/ATC connection

ATC 2

TRU/DPA
Shelf 1

See Table 3-1 for

TRU/DPA
Shelf 2

RF Frame 1

(Note 1)

DPA 1

DPA 4

DPA 5

DPA 8

TRU 1

6 5 4 3 2 1

TRU 8

6 5 4 3 2 1

TRU 9

6 5 4 3 2 1

TRU 16

6 5 4 3 2 1

See Table 3-3 for

RMC/TRU Shelf connection

TRU SHELF

SPLITTER 1

TRU SHELF

SPLITTER 4

TRU SHELF

SPLITTER 1

TRU SHELF

SPLITTER 4

Antenna

A1
A2
A3

A8
B1

B2
B3

B8

RX ANT

RMC 1A

RMC 1B

TX

Duplexer

Position 2

(Main

receive)

Antenna

(Diversity

receive)

Notes:

1.2.For diagram clarity, only one RF Frame is
shown. Other RF Frames with 20 channels
or less are connected and operated
identically to that of RF Frame 1.
TRU1 at TRU/DPA Shelf 1 of RF Frame 1 is
assigned as the CCH and TRU4 at the same
shelf is assigned as the backup CCH.

ATC 3

TRU/DPA
Shelf 3

DPA 9

DPA 10

ICRM HSMO

TRU 17

6 5 4 3 2 1

TRU 20

6 5 4 3 2 1

TRU SHELF

SPLITTER 1

TRU SHELF

SPLITTER 4

CE Frame

DMS-MTX DualMode Metrocell Cell Site Description

3-4 Cell Site Layouts

Figure 3-3
Block diagram of an omni Metrocell with 21 to 24 channels in one RF Frame

Control Channel

(Note 2)

ATC 1

See Table 3-2 for

PA/ATC connection

ATC 2

TRU/DPA
Shelf 1

TRU/DPA
Shelf 2

RF Frame 1

(Note 1)

DPA 1

DPA 4

DPA 5

DPA 8

TRU 1

6 5 4 3 2 1

TRU 8

6 5 4 3 2 1

TRU 9

6 5 4 3 2 1

TRU 16

6 5 4 3 2 1

See Table 3-3 for

RMC/TRU Shelf connection

TRU SHELF

SPLITTER 1

TRU SHELF

SPLITTER 4

TRU SHELF

SPLITTER 1

TRU SHELF

SPLITTER 4

Antenna

A1
A2
A3

RMC 1A

A8
B1

B2
B3

RMC 1B

B8

TX

Duplexer

RX ANT

Position 2

TX

Duplexer

RX ANT

Position 3

(Main

receive)

Antenna

(Diversity

receive)

Notes:

1.2.For diagram clarity, only one RF Frame is
shown. Other RF Frames with 21 channels
or mor are connected and operated
identically to that of RF Frame 1.
TRU1 at TRU/DPA Shelf 1 of RF Frame 1 is
assigned as the CCH and TRU4 at the same
shelf is assigned as the backup CCH.

ATC 3

TRU/DPA
Shelf 3

DPA 9

DPA 12

TRU 17

6 5 4 3 2 1

TRU 24

6 5 4 3 2 1

ICRM HSMO

411-2021-111 Standard 01.01 June 1996

TRU SHELF

SPLITTER 1

TRU SHELF

SPLITTER 4

CE Frame