401 - 380 - 349 Issue 2.0 November 1999 Lucent Technologies - Proprietary This document contains proprietary information of Lucent Technologies and is not to be disclosed or used except in accordance with applicable agreements Copyright 1999 Lucent Technologies Unpublished and Not for Publication All Rights Reserved EG19: Abis Interface Engineering Guideline for NR 8.6 and NR 8.5.1
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401 - 380 - 349Issue 2.0
November 1999
Lucent Technologies - ProprietaryThis document contains proprietary information
of Lucent Technologies and is not to be disclosed or usedexcept in accordance with applicable agreements
Copyright 1999 Lucent TechnologiesUnpublished and Not for Publication
This material is protected by the copyright laws of the United States and other countries. It may not bereproduced, distributed, or altered in any fashion by any entity (either internal or external to LucentTechnologies), except in accordance with applicable agreements, contracts, or licensing, without theexpress written consent of the Customer Training and Information Products organization and thebusiness management owner of the material.
Notice
Every effort was made to ensure that the information in this information product (IP) was complete andaccurate at the time of printing. However, information is subject to change.
Issue 2.0- November 1999 Lucent Technologies –ProprietarySee Notice on first page
iii
Contents
1 INTRODUCTION 1-1
About this Guideline 1-1
Overview 1-1
2 DIMENSIONING THE ABIS INTERFACE FOR E1 2-1
Dimensioning the Abis Interface 2-1
Abis Interface timeslot allocation 2-1
Releases prior to NR8.0 2-1
Abis Interface timeslot allocation 2-3
From release NR 8.0 2-3
Abis Timeslot Usage - Configuration Rules 2-4
Example 1 2-7
Example 2 2-8
Example 3 2-9
Example 4 2-10
Example 5 2-11
Example 6 2-12
Example 7 2-13
3 DIMENSIONING THE ABIS INTERFACE FOR T1 3-1
Dimensioning the Abis Interface 3-1
Abis Interface timeslot allocation 3-23-2
3-1
3-1
2-13
2-12
2-11
2-10
2-9
2-8
2-7
2-4
2-3
2-3
2-1
2-1
2-1
2-1
1-1
1-1
1-1
Contents Abis Interface Engineering Guideline
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Releases prior to NR8.0 3-2
Abis Interface timeslot allocation 3-3
Abis Timeslot Usage - Configuration Rules 3-4
Example 1 3-7
Example 2 3-8
Example 3 3-9
Example 4 3-10
Example 5 3-11
Example 6 3-12
Example 7 3-13
Summary 3-14
4 REFERENCES 4-1
References 4-1
5 ACRONYMS 5-1
Acronyms 5-1
COMMENTS FORM 5-35-3
5-1
5-1
4-1
4-1
3-14
3-13
3-12
3-11
3-10
3-9
3-8
3-7
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3-3
3-2
Issue 2.0- November 1999 Lucent Technologies –ProprietarySee Notice on first page
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1 Introduction
About this Guideline
This Engineering Guideline provides a description of the physical characteristics of the Abis Interface anddefines how it is dimensioned within the “Lucent GSM Network”.
Overview
The Abis Interface supports signaling and traffic circuits between the Base Transceiver Station (BTS-2000) and the Base station Controller Frame (BCF-2000). The E1 Abis Interface is based on a data rateof 2.048 Mbit/s, the T1 Abis interface is based on a data rate of 1.544 Mbit/s. E1 carries 32 x 64 Kbit/schannels, while T1 carries 24 x 64 Kbit/s channels.
Functions implemented at the Abis Interface are:
• Voice/Data traffic exchange• Signaling exchange between the BCF-2000 and BTS-2000• Transport of O&M information between the BTS-2000 and the BCF-2000
The bandwidth of each Abis Interface is shared by 31 timeslots1 for E1 and 24 timeslots for T1. Sometimeslots are allocated to carry traffic and others to carry signaling information.
When the Abis Interface is used in a Type 6 architecture, “Traffic” timeslots are subdivided into 4 x 16Kbit/s subrate GSM1800/GSM900GSM1900 traffic channels.2 The situation is shown schematically inFigure 1 (E1) and Figure 2 (T1).
Dual Band operation
Traffic channels from differing frequency bands may be freely mixed onto a single Abis link following thenormal configuration rules for single band use.
1 E1 has 32 timeslots but timeslot 0 is utilised for frame synchronisation.2 These are termed “full-rate” 16 Kbit/s traffic channels. “Half-rate” 8kbit/s traffic channels will beavailable in the future.
Introduction Abis Interface Engineering Guideline
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BTS-2000 BCF-2000
TS0 TS1 TS31
64Kbit/s
16Kbit
16Kbit
16Kbit
16Kbit
13Kbit
3Kbit
4 Sub-rateT ffichannels in
timeslot
Ove
r-he
ad
Voc
oded
Spe
ech
Bit transferRate
8 Bitframes
2.048 Mb/s
either or
64Kbit
Signallinglink
16Kbit
16Kbit
16Kbit
16Kbit
Lucent release 4method
Lucent release 5method
LAPD signalling concentration
function
Abis PhysicalCharacteristics
Figure 1: Physical characteristics of the E1 Abis Interface.
BTS-2000 BCF-2000
TS0 TS1 TS24
64Kbit/s
16Kbit
16Kbit
16Kbit
16Kbit
13Kbit
3Kbit
4 Sub-rateT ffichannels in
timeslot
Ove
r-he
ad
Voc
oded
Spe
ech
Bit transferRate
8 Bitframes
1.544 Mb/s
either or
64Kbit
Signallinglink
16Kbit
16Kbit
16Kbit
16Kbit
Lucent release 4method
Lucent release 5method
LAPD signalling concentration
function
Abis PhysicalCharacteristics
Figure 2: Physical characteristics of the T1 Abis Interface.
Issue 2.0- November 1999 Lucent Technologies –ProprietarySee Notice on first page
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2 Dimensioning the Abis
Interface for E1
Dimensioning the Abis Interface
Lucent BTS-2000 products can have up to 3 Abis interface connections (e.g. 3 x E1 2.048Mbit/s links).
• 2 Abis interfaces to a BCF-2000• 1 Abis link output to provide the multidrop capability
Alternatively:
• 1 Abis interface to a BCF-2000• 2 Abis interface outputs to provide the multidrop capability
One exception is the Lucent BTS-2000/2C which has a maximum of 2 Abis interfaces:
• 1 Abis interface to a BCF-2000• 1 Abis link output to provide the multi-drop capability.
Abis Interface timeslot allocation
Releases prior to NR8.0
Each TRX connected via the Abis interface requires three timeslots:
• 2 for voice traffic/data• 1 for signaling
Dimensioning the Abis Interface for E1 Abis Interface Engineering Guideline
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Each Cell/Sector connected via the Abis interface requires 1 timeslot for O&M signaling.
Example: for a 3-sectored (3,3,3) site;
# Timeslots = 3 x # TRXs + # Cells
= 3 x 9 + 3 = 30 timeslots required
The Lucent BSS configuration allows a maximum of 7 multi-dropped BTS-2000s on a single Abis
Interface connection.3
The maximum number of TRXs which can be placed on a single Abis is 10.
i.e. 3 x # TRXs + # Cells
= 3 x 10 + 1
= 31 (Max. No. of timeslots available on a single Abis
A single cell cannot be split across different Abis links. An omni 11 or omni 12 cannot be supported withRelease 4 software release. A 3-sectored 4,4,4 or 4,4,3 can be supported by placing the 3rd cell on asecond Abis.
3 Multidrop indicates that more that one BTS can utilise the same Abis interface connection
Dimensioning the Abis Interface for E1 Abis Interface Engineering Guideline
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SYNC ST T T ST T T ST T T ST T T ST T T
ST T T ST T T ST T TT orS07
T orS05
T orS04
T orS03
T orS04
S01T orS06
TR
X1
TR
X2
TR
X3
TR
X4
TR
X5
TR
X6
TR
X7
TR
X8
TR
X9
TR
X10
Where T =Traffic Channel ST = TRX Signalling
S0n = Signalling for Cell n
Figure 3: Timeslot allocation with Release 4 software release.
Abis Interface timeslot allocation
From release NR 8.0 Network Release 8.0 provides the LAPD Link Concentrator Function. This allows the concentration of 4logical signaling links onto one physical timeslot on the Abis Interface (i.e. .4 x 16Kbit/s subrate slots).This allows a more economical use of the Abis transmission capacity. Both TRX related signaling andcell (O&M) related signaling can be combined into a single timeslot, but all signaling channels sharing atimeslot must be in the same cell.
Each TRX connected via the Abis interface requires:
• 2 timeslots for voice traffic/data• 1 timeslot for signaling. 1 timeslot can accommodate signaling for:
− up to 4 TRXs (all TRXs must be in the same cell)
or
− 3 TRXs + 1 O&M ( all TRXs must be in the same cell and O&M must relate tothat cell)
With these capacity increases, a single Abis interface can support up to 12 TRXs in multicell or singlecell configurations
Dimensioning the Abis Interface for E1 Abis Interface Engineering Guideline
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Abis Timeslot Usage - ConfigurationRules
This Abis LAPD Concentration can be used from GSM 8.0 onwards and on the BTS-2000 (with MRIF)and BTS-2000/2C, but is not usable on the BTS-2000P (with RIF) or the RBS-900. The maximum recommended concentration rate is 4:1 (i.e. one BTC and three RT signaling slots perAbis timeslot or four RT signaling slots per Abis timeslot). If a cell (BTS) requires more than one Abis timeslot containing signaling channels (i.e. cells with morethan 3 RTs) then the load (number of signaling channels) per Abis timeslots should be balanced (asdescribed in table opposite).
• The Abis timeslots containing BTC signaling information will be configured on Abis
timeslots 31, 30 and downwards.
• Abis timeslots 1, 2 and upwards will be configured as traffic slots (containing trafficchannels). If an additional RT signaling slot is required, the Abis timeslot behind thelast used “traffic” timeslot will be used.
• Each BTC requires it’s own Abis timeslot. It is impossible to concentrate BTC signalingslots (of different cells) into one 64kbit/s Abis timeslot.
• Due to FEICE-4881 there will be no merge of signaling channels of different cells(BTSs) into one Abis timeslot.
• The Abis timeslots containing BTC signaling channels will be filled with signalingchannels for up to 3 RTs (the number of RT signaling channels depends on thenumber of RTs per cell and is given in Table 1).
Dimensioning the Abis Interface for E1 Abis Interface Engineering Guideline
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RT signaling and traffic channels:
For each RT a signaling channel is set first and then the traffic channels are created. The first RTsignaling channels will be set to the Abis timeslot containing the BTC signaling channel of the appropriatecell (e.g. timeslot 31). If this Abis timeslot is already filled (as described in Table 1) then a new Abis
timeslot (containing RT signaling channels) will be created, followed by the Abis timeslots containing RTtraffic channels. The same Abis configuration will be used for both BSS types: BCE-2000 and BCF-2000. Remarks:
• This Configuration Rule will be used by the Site Independent Scripts to support thecreation of new BTSs.
• If an additional RT will be installed at a existing BTS the operator is not forced to useTable 1 (For example, if there is a BTS containing 3 RTs with all signaling channelsin TS31 it is not necessary to move the RT signaling channel of RT:2 to the Abis
timeslot containing the signaling information for the new RT:3).
• Possible restrictions in reference to the feature “BTS-2000/2C extension to 10 TRX”are not considered in this Configuration Rule.
Dimensioning the Abis Interface for E1 Abis Interface Engineering Guideline
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Example 1
For a 3-sectored (4,4,4) site:Traffic Timeslots required = 2 x # TRXs = 2 x 12 = 24
Perform the signaling timeslot calculation on a per cell basis.
# Signaling Timeslots for cell A = # TRX + 1 = 4 + 1= 2 4 4
Signaling Timeslots required for cell B and C are the same in this example.
RT:1 Traffic2526 F Signaling BTC, RT:0,127 E Signaling BTC, RT:0,128 D Signaling BTC, RT:0,129 C Signaling BTC, RT:0,130 B Signaling BTC, RT:0,131 A Signaling BTC, RT:0,1
Table 6: Performing a Timeslots calculation on a per cell basis (2-2-2-2-2-2 Multicell)
Dimensioning the Abis Interface for E1 Abis Interface Engineering Guideline
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Example 6
8-4 Multicell or Multidrop
Traffic Timeslots required = 2 x # TRXs = 2 x 12 = 24
Perform the signaling timeslot calculation on a per cell basis.
# Signaling Timeslots for cell A = # TRX + 1 = 4 + 1 = 2 4 4
# Signaling Timeslots for cell B = # TRX + 1 = 8 + 1 = 3 4 4
4 Multidrop indicates that more that one BTS can utilise the same Abis interface connection
Dimensioning the Abis Interface for T1 Abis Interface Engineering Guideline
Issue 2.0- November 1999 Lucent Technologies –ProprietarySee Notice on first page
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ST T T ST T T S01
TRX6
TRX7
Where T =Traffic Channel ST = TRX Signalling
S0n = Signalling for Cell n
ST T T ST T T ST T T ST T T ST T T
TRX1
TRX2
TRX3
TRX4
TRX5
Figure 6: Timeslot allocation with Release 4 software release.
Abis Interface timeslot allocation
From release NR 8.0
Network Release 8.0 provides the LAPD Link Concentrator Function. This allows the concentration of 4logical signaling links onto one physical timeslot on the Abis Interface (i.e. .4 x 16Kbit/s subrate slots).This allows a more economical use of the Abis transmission capacity. Both TRX related signaling andcell (O&M) related signaling can be combined into a single timeslot, but all signaling channels sharing atimeslot must be in the same cell.
Each TRX connected via the Abis interface requires:
• 2 timeslots for voice traffic/data• 1 timeslot for signaling. 1 timeslot can accommodate signaling for:
− up to 4 TRXs (all TRXs must be in the same cell)
or
− 3 TRXs + 1 O&M ( all TRXs must be in the same cell and O&M must relate tothat cell)
With these capacity increases, a single Abis interface can support up to 10 TRXs in multicell or singlecell configurations
Dimensioning the Abis Interface for T1 Abis Interface Engineering Guideline
3-4 Lucent Technologies –ProprietarySee Notice on first page
Issue 2.0 - November 1999
Abis Timeslot Usage - ConfigurationRules
This Abis LAPD Concentration for T1 can be used from GSM 8.0 onwards and on the BTS-2000 (withMRIF2) and BTS-2000/2C, but is not usable on the BTS-2000P (with MRIF, RIF) or the RBS-900. The maximum recommended concentration rate is 4:1 (i.e. one BTC and three RT signaling slots perAbis timeslot or four RT signaling slots per Abis timeslot). If a cell (BTS) requires more than one Abis timeslot containing signaling channels (i.e. cells with morethan 3 RTs) then the load (number of signaling channels) per Abis timeslots should be balanced (asdescribed in table opposite).
• The Abis timeslots containing BTC signaling information will be configured on Abis
timeslots 24, 23 and downwards.
• Abis timeslots 1, 2 and upwards will be configured as traffic slots (containing trafficchannels). If an additional RT signaling slot is required, the Abis timeslot behind thelast used “traffic” timeslot will be used.
• Each BTC requires it’s own Abis timeslot. It is impossible to concentrate BTC signalingslots (of different cells) into one 64kbit/s Abis timeslot.
• Due to FEICE-4881 there will be no merge of signaling channels of different cells(BTSs) into one Abis timeslot.
• The Abis timeslots containing BTC signaling channels will be filled with signalingchannels for up to 3 RTs (the number of RT signaling channels depends on thenumber of RTs per cell and is given in Table 1).
RT signaling and traffic channels:
For each RT a signaling channel is set first and then the traffic channels are created. The first RTsignaling channels will be set to the Abis timeslot containing the BTC signaling channel of the appropriatecell (e.g. timeslot 31). If this Abis timeslot is already filled (as described in Table 1) then a new Abis
timeslot (containing RT signaling channels) will be created, followed by the Abis timeslots containing RTtraffic channels.
Dimensioning the Abis Interface for T1 Abis Interface Engineering Guideline
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Issue 2.0 - November 1999
The same Abis configuration will be used for both BSS types: BCE-2000 and BCF-2000. Remarks:
• This Configuration Rule will be used by the Site Independent Scripts to support the
creation of new BTSs.• If an additional RT will be installed at a existing BTS the operator is not forced to
use Table 1 (For example, if there is a BTS containing 3 RTs with all signalingchannels in TS31 it is not necessary to move the RT signaling channel of RT:2 tothe Abis timeslot containing the signaling information for the new RT:3).
• Possible restrictions in reference to the feature “BTS-2000/2C extension to 10TRX” are not considered in this Configuration Rule.
Dimensioning the Abis Interface for T1 Abis Interface Engineering Guideline
Issue 2.0- November 1999 Lucent Technologies –ProprietarySee Notice on first page
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Example 1
For a 3-sectored (3,3,3) site:Traffic Timeslots required = 2 x # TRXs = 2 x 9 = 18
Perform the signaling timeslot calculation on a per cell basis.
# Signaling Timeslots for cell A = # TRX + 1 = 3 + 1 = 1 4 4
Signaling Timeslots required for cell B and C are the same in this example.
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