(e) gprs overview

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(E) GPRS Overview

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(E) GPRS Overview 14/08/11 1.0 1 of 12

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(E) GPRS Overview

14thof August 2011


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Table of Contents

1.INTRODUCTION................................................................................... 42.PSINTERFACES OVERVIEW....................................................................... 5

2.1.NETWORK ARCHITECTURE............................................................................................ 52.2.TRXPLANNING OVERVIEW........................................................................................... 62.3.EXTRA ABISTIMESLOTS PLANNING.................................................................................. 7

2.3.1. Extra Abis Nibbles ............................................................................ 72.3.2. Bonus Abis Nibbles ........................................................................... 72.3.3. Basic Abis Nibbles ............................................................................ 7

2.4.ATERMUXPS ....................................................................................................... 83.MAIN (E)GPRS PARAMETERS..................................................................... 94.ABIS/ATER OVER SATELLITE SITES/BSC ........................................................... 105.NETWORK ARCHITECTURE IN NKTT ............................................................... 116.CONCLUSION .................................................................................... 12


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Table of FiguresFigure 1:Network Architecture ........................................................................................ 5Figure 2: TRX Timeslots ................................................................................................. 6Figure 3: Abis Timeslots................................................................................................. 7Figure 4: ATERMUX ....................................................................................................... 8Figure 5: VSAT Parameters Values .................................................................................. 10


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1.INTRODUCTION The Aim of this document is to provide an overview on the PS network as well as a brief

explanation on the main interfaces

This document also includes the main (E) GPRS parameters that control the PS resourcesmanagement and the features activations.

The set of parameters that need to be fine tuned for ABIS/ATER over satellite Sites/BSCs willbe highlighted with the recommended values.

The Architecture in Nouakchott city will also be explained in this report.


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2.PS INTERFACES OVERVIEWThe aim of this section of the document is to present a quick overview on the PS main interfaces withsome details and specifications.

2.1.Network ArchitectureThe figure below shows the network architecture.

The main interfaces in CS as well as PS are shown in the figure.

Figure 1:Network Architecture


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2.2.TRX Planning OverviewThe target of TCH capacity planning is to balance the radio resource sharing between CS traffic (GSM)and PS traffic (GPRS/EDGE) on TRX resource.

Figure 2: TRX Timeslots

TCH channel can handle PDCH to carry PS traffic. However, some parameters need be set to specificvalues.

The BCCH timeslot and the Static SDCCH cant carry PS traffic.

The parameters are mentioned in the Main GPRS Parameters section of this document.

TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7

TRX#1 BCCH SDCCH TCH TCH TCH TCH TCH TCH

TRX#2 SDCCH TCH TCH TCH TCH TCH TCH TCH


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2.3.Extra ABIS Timeslots Planning

Figure 3: Abis Timeslots

The Abis Timeslots Types are stated below with an explanation for each:

2.3.1.Extra Abis Nibbles

Extra Abis nibbles are shared at BTS level. They can be shared among all the TREs of the BTS to whichthey have been associated (by the OMC and the BSC).

2.3.2.Bonus Abis Nibbles

Bonus Abis nibbles are shared at BTS level, as for extra Abis nibbles. They can be shared among all theTREs of the BTS.

The dynamic SDCCH channel supports TCH traffic. So, the corresponding basic Abis nibble cannot beused for PS traffic.

2.3.3.Basic Abis Nibbles

Basic Abis nibbles are mapped to an RTS currently available for PS traffic or mapped to an RTScurrently used as an MPDCH.

Basic Abis nibbles are shared at the level of the BTS sector. They can be shared among all the TREs ofa same BTS.


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2.4.ATERMUX PS

Figure 4: ATERMUX

The Atermux interface is a set of 2 Mbit/s PCM links, i.e. a PCM is made of 32 timeslots of 64 Kbit/scarrying either only PS traffic or a mix of PS traffic and CS traffic.

The CS timeslots are made up of:

Speech timeslots composed of 4 speech nibbles at 16 Kbit/s. A speech nibble carried the voice

for a transaction or data in circuit mode. A speech nibble is also called CIC. Four 16 Kbit/snibbles from 64 Kbit/s timeslot of the PCM link.

Speech signaling N7.

Other specific O&M timeslots not related to speech (X25, Qmux, Alarm octet).

The PS timeslots on the ATERMUX contain:

The timeslots devoted to the transport of PS data composed of 4 PS nibbles at 16 Kbit/s. A PSnibble on the ATERMUX is called GIC. The content of the GIC is called GCH. Four of 16 Kbit/snibbles from a 64 Kbit/s timeslot of the PCM link.

The PS LapD link at 64 Kbit/s supports the signaling channel. There is one LapD link perATERMUX PCM. The signaling channel shares the traffic over LapD links. The content of a GPRS

signaling channel is called GSL.


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3.MAIN (E) GPRS PARAMETERSThe main parameters are listed below with the explanations and the recommended rules if any:

PREF_MARK: It is on the TRX level and it must be set to 0 so that the TRX can carry data calls. If it isset to any other value the TRX will not carry data calls.

EN_GPRS: This flag enables/disables the GPRS on a cell. It must be set to 1 in order to enable theGPRS. MAX_PDCH (will be explained below) must be greater than 0 in order that the GPRS data arecarried on the cell level.

EN_EGPRS: This flag enables/disables the EGPRS on a cell. It must be set to 1 in order to enable theEGPRS. MAX_PDCH (will be explained below) must be greater than 0 and the TRX used must be highpower 8PSK in order that the EGPRS data are carried on the cell level. Also good ABIS and ATERMUXdimensioning must be performed in order to avoid congestion on these interfaces as the EGPRS dataare carried with high rates which utilizes resources.

MIN_PDCH: It is the minimum number of Packet Data Channels that are always allocated to the MFS.It must be set to a value lower or equals than the value of MAX_PDCH_HIGH_LOAD. If this parameteris set to high value; the congestion might increase on the GSM as high number of resources will bealways defined to the MFS for data calls.

MAX_PDCH_HIGH_LOAD: It is the maximum number of PDCH that can be allocated to the MFS whenthe CS traffic is high.

MAX_PDCH: It is the maximum number of PDCH that can be allocated to the MFS on a cell.

TBF_DL_INIT_CS: Initial value of the coding scheme that will be used in the DL. It is mandatory thatTBF_DL_INIT_CS


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4.ABIS/ATER OVER SATELLITE SITES/BSCThe table below summarizes the values of the parameters that must be fine tuned for ABIS/ATER oversatellite Sites/BSCs

Figure 5: VSAT Parameters Values


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5.NETWORK ARCHITECTURE IN NKTTNouakchott city is covered by 6 BSC which are stated below:

BMX_Nouakchott1

BMX_Nouakchott2

BMX_Nouakchott3

BMX_Nouakchott4

BMX_Nouakchott5

BMX_Nouakchott6

It is covered by 4 LACs which are stated below:

131

132

133

134

It has to be mentioned that any site that is under the BSCs BMX_Nouakchott1 to BMX_Nouakchott6 butnot under the LACs from 131 to 134 is not considered in Nouakchott city

Each BSC is connected to 2 ATERMUX dedicated only for PS. An audit will be performed on theATERMUX after the (E) GPRS is on air as a double check for the resources and capacity.

Each BSC is dimensioned by 1 GPU which exists in the MFS. Also an audit on the GPUs will beperformed after the MFS is on air in order to double check the capacity and utilizations.


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6.CONCLUSIONThis document gave an overview for the most important interfaces as well as for the Networkarchitecture.

This document showed the main (E) GPRS parameters that manage the PS comportment for anetwork.

It has to be mentioned that a template for the values of the main parameters mentioned in thisreport will be submitted in an excel sheet

End of Document

(e) gprs overview

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