09a_(e)gprs handling in bss

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6-128338 v1 / 17.12.2003 / M. Weingart1

GPRS/EGPRS handlingGPRS/EGPRS handlingin BSSin BSSBSS S11



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Introduction to GPRS/EGPRS in BSC

• defineGPRS Networkstructure

• defineGPRS Hard- and Software requirements

• explain GbInterfaceprotocol

• explainGRPS/EGPRS cell parameter

• explainusageof dynamicAbis

After studyingthismoduleyoushouldbeableto:

Refer to S11 Documentation:• Descriptions\ Feature Descriptions\ Data – IP-Multimedia\ (E)GPRS in BSC

Refer to S11 Documentation:

• Descriptions\ Feature Descriptions\ Data – IP-Multimedia\ (E)GPRS in BSC

For additional information refer to S11 Documentation:• Descriptions\ Hardware descriptions\ Plug-in Unit Descriptions\…

• Descriptions\ Feature Descriptions\Data – IP-Multimedia\GPRS in BSC\ GPRS in BSC\Gb interface configuration and state management \The protocol stack of the Gbinterface

• Optimise and Expand\ Capacity and Coverage\ Dynamic Abis Pool Handling

• Descriptions\ System Descriptions\ Nokia Base Station Subsystem Description\ Nokia BaseStation Subsystem solutions\ Nokia Base Station Subsystem data\ Dynamic AbisAllocation

• Descriptions\ System Descriptions\ Nokia Base Station Subsystem Description\ Nokia BaseStation Subsystem solutions\ Nokia Base Station Subsystem data\ Support of

PCCCH/PBCCH

• Optimise and Expand\ Rehosting\ Modifying GPRS\ Enabling EGPRS on a cell



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GSM Data Solutions

Internet

BTS BSC

MSC

Internet

PSTN

GPRSBackbone

IP Network

GPRS Core

HSCSD-Core

SGSN GGSN

Gb-If


• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ Overview of (E)GPRS in BSC



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Packet switched

Datanetworks

Virtual circuit (VC) No VC(CONS) (CLNS)

• No connection needed• Resources are shared between different user

sessions, not dedicated• Resources are requested on demand, more

efficient use• Packets are not sent in real time⇒⇒⇒⇒

buffering and delay

• Error correction and detection possible• Charging is usually based on volume⇒⇒⇒⇒

number of packets

Telephonenetworks

Physical circuit(CONS)

• End to end connection (call)establishment needed

• Dedicated resources (e.g. PCM-tsl) forone user are reserved during callestablishment

• Only 30-40% of resources areeffectively used for speech transfer

• Speech is transferred in real time• Speech does not accept delays• Errors in transmission are not so critical

for speech• Charging is usually based on time

Circuit switched





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GSM and GPRS Networks

InterPLMNNetwork

Integrated NetworkManagement

SS7NW

SMSC

HLR

BillingSystem

Home LocationRegister

Short MessageService Centre

MSC

PSTNNetwork

BTSBSC

GPRSBackboneIP Network

GGSN

Gateway GPRSSupport Node

SGSNServing GPRSSupport Node

BG

Border Gateway

Charging

CG

Gateway

LegalIntercept

DNSDomainName

Systems

PCU

Intranet

Router

Server

Local Area NW

Corporate

Internet

Firewall





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GRRS Soft- and Hardware requirements

B C S U

PSA20PSFP

O M U

S W 1 C

S W 1 C

B C S U

B C S U

B C S U

B C S U

B C S U

E T 5 C E T 5 C

E T 5 C E T 5 C

E T 5 C

E T 5 C

E T 5 C

C L A C

C L O C

M C M U

M C M U

O M U

E T 5 C

E T 5 C

W D D C

W D D C

B C S U

B C S U

B C S U

PSA20PSFP

• BSCE and BSCi have maximal one PCU per

BCSU.• BSC2E/A, BSC2i or BSC3i can have optional a

second PCU Plug-in-unit per BCSU.

• GSWB capacity minimum is 192 PCMs (3SW64B PIU per MCMU). If two PCUs areused, the GSWB has to be updated from 192to 256 PCMs (4 SW64B PIU per MCMU)

• GPRS is supported since S9 and EGPRS sinceS10.5 ED Software level.





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PCU: Location, Front View

ZWTI:P:BCSU,<NBR>;MML: Check HW configuration

DN99572382

PCM

LD1

LD2

LD3

LD4

LD5

LD6

EUROCONNECTOR (3x16)

SERVICE TERMINAL

RJ45

LAN (10/100 BASE Tx)

RJ45

LAN (10/100 BASE Tx)

RJ45

P2

J2

J3

J5

BCSU

One PCU must be installed in every BCSU!


• Descriptions\ Hardware descriptions\ Plug-in Unit Descriptions\…



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Packet Control Unit Functions

• GPRS radio resource allocation and management

• GPRS radio connection establishment and management

• data transfer

• coding scheme selection

• PCU statistics

The PCU controls the GPRS radio resources and acts as the key unit in the

following procedures:





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• One BCSU has up to 2 PCUs, that means BSC contains max. 16 activePCUs, plus two redundant PCUs.

• One PCU can handle a maximum of 64 BTSs and 128 TRXs

• One PCU can handle the GPRS traffic of 256 radio time slots includingPBCCH/PCCCH + default GPRS + EDAP channels

• The maximum number of connected traffic channels (16kbit/s) in GPRSuse in a BSS is

• 2048 (that is, 8 times 256) for BSCE and BSCi• 4096 (16 times 256) for BSC2A, BSC2E and BSC2i, and• 6144 (24 times 256) for BSC3i.

PCU Capacity






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PCU Interfaces

Power PC

ET

ETsETs

PCU

DSP1

DSP1

GSWB

DSPDSP

DSPDSP

DSP

8DSP

8

Packets inTRAU frames

Packets in FR

internalbus

Mail Box

DMC bus

ETsETs

BTSs

4M internal pcm / 256 channels

SGSN

Gb Abis

ET

4M internal PCM:FR: bearer channel + optional load

sharing redundant bearer






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Gbinterface configuration

SGSN

GbInterface

GSW

PAPU

ET

BSC

GSW

BCSU

ET

PCU


• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ Gbinterface configuration and state management \The protocol stack of the Gbinterface

• Reference\ Interface Specifications\ BSC-SGSN Interface Specification BSS GPRSProtocol (BSSGP)

• Reference\ Interface Specifications\ BSC-SGSN Interface Specification Network ServiceProtocol (NS)



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Transmission Solutions of Gb Interface

ET

TransmissionNetwork

ET

BSC

TCSM

MSC

Frame Relaynetwork

ET

ET

ET

ET

SGSN

1

2

3

Refer to S11 Documentation:• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ Gb

interface configuration and state management \The protocol stack of the Gbinterface

• Reference\ Interface Specifications\ BSC-SGSN Interface Specification BSS GPRSProtocol (BSSGP)• Reference\ Interface Specifications\ BSC-SGSN Interface Specification Network ServiceProtocol (NS)

The Gbinterface is located between the BSC and the SGSN, and it is implemented using Frame Relay (FR). The Frame Relay can be either point-to-point (PCU – SGSN) or there can be a Frame Relay networklocated between the BSC and the SGSN. The Frame Relay network will be comprised of third-party off-the-shelf products. The following figure displays examples of the Gbinterface transmission solutions:In the first solution (1) spare capacity of the Aterand the A interfaces is used for the Gbinterface. TheGbtimeslots are transparently through connected in the TCSM and in the MSC. The second solution (2)represents a transmission network that provides a point-to-point connection between the BSC and theSGSN. In the third solution (3) the Frame Relay network is used.Gbinterface allows many users to be multiplexed over the same physical link using Frame Relay.Bandwidth is allocated to a user upon activity (when data is sent or received) and is reallocatedimmediately thereafter. This is in contrast to the A interface, where a single user has the exclusive use of a dedicated physical resource throughout the lifetime of a call irrespective of activity.A Gbinterface Bearer channel can use 1 to 30 64kbit/s timeslots.



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Gb-Interface

FR

SGSNBSC

L1bis L1bis

BSSGP BSSGP

LLC

SNDCP

Network Servicecontrol part

FR


Gb-IF

NetworkService

Subnetwork DependentConvergence Protocol

Layer 1 physical connection

Logical Link Control

BSS GPRS protocol layer

Frame Relay


PhysicalLayer

State of Services

GPRSSignalling

Refer to S11 Documentation:•Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\Gb interface

configuration and state management \The protocol stack of the Gb interface•Reference\ Interface Specifications\ BSC-SGSN Interface Specification BSS GPRS

Protocol (BSSGP)•Reference\ Interface Specifications\ BSC-SGSN Interface Specification Network ServiceProtocol (NS)

S i g n a l l i n g p l a n e o f t h e

G b i n t e r f a c e

T r a n s m i s s i o n p l a n e o f t h e

G b i n t e r f a c e



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Gb-Interface Identifier

BVCI

DLCI

NSEINS-VCI

BC

BSSGP

FRL1bis


BSC

BSSGP Virtual Connection Identifier

Network Service EntityNetwork Service Virtual Connection Identifier

Data Link Connection IdentifierBearer Channel







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Principle of Frame Relay Networks

switch

switch

switch

switch

SGSN

BSC 2

BSC 1

B C

B C

B C

B C

B C

NSVCI

DLCI

Network Service Virtual Connection Identifier

Data Link Connection Identifier

B C

B C

NSVCI 7

NSVCI 7

DLCI

10

10

DLCI20

20

DLCI

30

30

Unique betweenneighbors of aBearer Channel

Uniquebetweenendpointsof VC

NSVCI 9 NSVCI 9

DLCI

30

30

DLCI

40

40DLCI

20

20DLCI

10

10







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GbInterface

PCU2

PCU1

PCU3

BTS_3

BTS_6

RA 1

BTS_8

BTS_22

RA 2

LA

PCU3

BTS_22

RALA

Bearer Channel_5

Bearer Channel_6

Bearer Channel_2

Bearer Channel_1

Bearer Channel_3

Bearer Channel_4

DLCI_16

DLCI_17

DLCI_16

DLCI_17

DLCI_16

DLCI_16

DLCI_17

DLCI_17

DLCI_18

DLCI_16

BVCI_3

BVCI_0NS-VCI_7

NS-VCI_2

NSEI_1

NS-VCI_5

NS-VCI_8

NS-VCI_3

BVCI_0

BVCI_6

NSEI_2

NS-VCI_4

NS-VCI_1

NS-VCI_11

BVCI_8

BVCI_0

NSEI_3

BVCI_22

BVCI_22

BVCI_0NS-VCI_6

NS-VCI_9

NSEI_7

BVCI_3

BVCI_0 NS-VCI_7

NS-VCI_2

NS-VCI_5

NS-VCI_8

NS-VCI_3

BVCI_0

BVCI_6

NSEI_1

NSEI_2

NS-VCI_4

NS-VCI_1

NS-VCI_11

BVCI_8

BVCI_0

NSEI_3

BVCI_22

BVCI_22

BVCI_0 NS-VCI_6

NS-VCI_9

NSEI_7

PAPU1

PAPU2

PAPU3

SGSN

BSSGP

NS

FR

Data

SignalData & Signal

BSS2

BSS1





The Gb interface has a protocol stack consisting of three layers:

Physical Layer, Network Service Layer (NS) and the Base StationSystem GPRS Protocol (BSSGP).

Network Service Virtual Connection (NS-VC)

NS-VCs are end-to-end virtual connections between the BSS and SGSN. The physical link in the Gbinterface is the Frame Relay Bearer channel. An NS-VC is the permanent virtual connection (PVC) andcorresponds to the Frame Relay DLCI (Data Link Connection Identifier) together with the Bearer channel

identifier. Each NS-VC is identified by means of an NS-VCI (Network Service Virtual ConnectionIdentifier).

Network Service Virtual Connection Group (NSE)

NSE identifies a group of NS-VCs in the BSC. The NSEI is used by the BSC to determine the NS-VC thatprovides service to a BSSGP Virtual connection (BVC). One NSE isconfigured between two peer NSs. Ateach side of the Gb interface, there is a one-to-one correspondence between a group of NS-VCs and anNSEI. The NSEI has an end-to-end significance across the Gb interface at NS level, but only localsignificance at the BSSGP level. One NSE per PCU is supported and within one NSE a maximum of fourNS-VCs are supported.



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Gbover IP interfaceconfiguration(BSC2i)

SGSN

GbInterface

PAPU

BSC2i

BCSU PCU

ExternalLan

IP network

Refer to S11.5 Documentation:

• Descriptions\ Feature Descriptions\ Data \ (E)GPRS in BSC\ Gbinterface configurationand state management \The protocol stack of the Gbinterface


• Reference\ Interface Specifications\BSC-SGSN Interface Specification NetworkService Protocol (NS)

If insteadof a BSC3i, thereis a BSC2i used,thenESB20switches are replaced by external LANswitches



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Gbover IP interfaceconfiguration(BSC3i)

SGSN

GbInterface

PAPU

BSC3i

BCSUPCU

ESB20IP network


• Descriptions\ Feature Descriptions\ Data \ (E)GPRS in BSC\ Gbinterface configurationand state management \The protocol stack of the Gbinterface


• Reference\ Interface Specifications\BSC-SGSN Interface Specification NetworkService Protocol (NS)

If insteadof a BSC3i, thereis a BSC2i used,thenESB20switches are replaced by external LANswitches



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GbInterface Protocol (IP)

SGSNBSC

LLC

SNDCP

GbIP-IF

Subnetwork DependentConvergence Protocol

Logical Link Control

BSS GPRS protocol layer


State of Services

GPRSSignalling UDP


L2

L1

UDP

IP


L2

L1

BSSGP

Physicallayer

Layer 1 physical connection

User DatagramProtocol layer

Layer 2 data link layer

IP addressrouting

BSSGP

IP


• Descriptions\ Feature Descriptions\ Data \ (E)GPRS in BSC\Gbinterface configuration andstate management \The protocol stack of the Gbinterface

• Reference\ Interface Specifications\ BSC-SGSN Interface Specification BSS GPRS Protocol(BSSGP)


L1 =layer 1physical layer Ethernet cable

L2 =Datalink layer for ethernet (MACaddress) mediumaccess control address(fixed address.ItsauniqueMACaddress which every network interface has..)..Hubs or switches can switch data without IPaddressingandbyjust usingL2 MACaddressing. (Other name usedfor suchL2switches are tranparentbridgeor multiport transparentbridgewhich has several interfaces..)

L2 isconsideredaswitching functionality

L3 isconsideredarouting functionality



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GbInterface Identifier (IP)

BVCI

LPNBR

NSEINS-VCI

BSSGP

UDP

L2


BSC

BSSGP Virtual Connection Identifier

Network Service EntityNetwork Service Virtual Connection Identifier

Local User Datagram Protocol Port Number

Remote User Datagram Protocl Port Number

IP

L1

RPNBR

RIP Remote IP addressRHOST RemoteHostName(If DNS exists)


• Descriptions\ Feature Descriptions\ Data \ (E)GPRS in BSC\Gbinterface configuration andstate management \The protocol stack of the Gbinterface

• Reference\ Interface Specifications\ BSC-SGSN Interface Specification BSS GPRS Protocol(BSSGP)


The Network Service Parameter NS-VCI (Network Service Virtual Connection Identifier) and BVCI (BSSGPVirtual Connection Identifier) have to be defined unique at the end devices. In a simple BSC-SGSN point-to-point connection neighbours are consequentially end devices.Æ Parameters have to be the same inBSC and SGSN.

While creation LPNBR, RPNBR, NS-VCI and NSEI have to be defined. The BVCI will be createdautomatically by the System.

-RDW and RSWare parameters which determine loadsharing statuses betweenNS-VC’s

-RDW and RSWcan be consideredaspart of theNetworkServicecontrol part sincethe NSEI controlsloadsharing bewteenNS-VC’s



BSSGP Virtual Connection (BVC)

BVCsare communication paths between peer NS user entities on the BSSGP level. Each BVC is supportedby one NSE and it is used to transport Network Service Service Data Units (NS SDUs) between peer NSusers. Each BVC is identified by means of a BVCI which has end-to-end significance across the Gbinterface. Each BVC is unique between two peer NSs. Within BSS the user identifies a cell uniquely by aBVCI. The BVCI value 0000 (hex) is used for signalling and the value 0001 (hex) is reserved for point-to-

multipoint (PTM). PTM is not supported. All other values can be used for cell identifiers.

Thefollowingrouleshaveto beheeded:

• NESI must be identical and unique at BSS and SGSN side

• One PCU is equivalent to one NSE (Network Service Entity)

• 1 PAPU can serve up to 64 PCUs that means 64 NSEs

• 1 NSE is connected with one ore more permanent virtual connections called NS-VC

• The BC (Bearer Channel) is defined by PCM and TLS in 64kbit/s steps

• DLCI is unique within one bearer channel

• DLCI has to be identical one both sides only in case of point-to-point FRconnections

• NS-VCI capacity can be controlled with Committed Information Rate (CIR) in16kbit/s steps

• One BC supports several DLCsand can also shared by several NS-VCIs

• The sum of the CIR on the BC has to be less or equal to the capacity of BC

• BVCI has an end-to-end significance

• A cell can be identified by one BVCI

• BVCI is unique inside one NSE

• one NS-VCI supports several BVCs

• BVCI =0 is reserved for signalling purposes inside one NSE.



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Exercise: Read out Gb IF configuration

Bearername=__________________________

BearerID=______ PCM= ____ TSL________ Bearer Rate=_____

NSVCI=_____ DLCI=_____ CIR=_____

Bearername=__________________________


NSVCI=_____ DLCI=_____ CIR=_____

Bearername=__________________________


NSVCI=_____ DLCI=_____ CIR=_____

Bearername=__________________________ BearerID=______ PCM= ____ TSL________ Bearer Rate=_____

NSVCI=_____ DLCI=_____ CIR=_____

PAPU

NS-VCI=___

NS-VCI=___

NS-VCI=___

NS-VC=___

SGSN

NS-VCI=___ Name _____

NSEI__________


BSC



NSEI__________

NSEI__________

NSEI__________

BCSU=_____ PCU index=_____


Exercise: Read out GbInterface configuration. Duration: approx. 20min

Fill out the missing information on the slide. Write down the used MML commands.

1. Which command group handledthe Frame Relay Bearer Channel?

Command:___________________________________________________________________

2. How can you output the used Frame Relay Parameter?

Command:___________________________________________________________________

3. Fill in all Network Service layer data into the slide.

Command:___________________________________________________________________

4. What is the command to change the NSVCI state?

Command:___________________________________________________________________



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GPRS cell specificparameter

B

Segment-1

BTS-1

(E)GPRS territory TRX1

TRX2

TRX3

GTRX=Y

GENA=Y

EGENA=Y

GTRX=N

Example:

Segment1:

BTS1:

TRX1: TRX2 and 3:

GPRS enabled TRX

EGPRS enable

GPRS enable

MML: ZEQO:SEG=<x>:GPRS;GTRX Transceiver specificparameter:

MML: ZERO:BTS=<x>,TRX=<x>;EGENABTS specificparameter:

MML: ZERO:SEG=<x>,TRX=<x>;GENASegment specificparameters:


• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ Radioresource management

First the operator has to activate the GPRS feature in the BSC with the cell- specific parameterGPRSenable (GENA)and define which TRXsare capable of GPRS with the parameterGPRS enabled TRX(GTRX) . To activate the EGPRS feature, the operator uses the BTS-specific parameterEGPRS enable(EGENA) . The BTS can contain both EDGE-capable and non-EDGE-capable TRXs(HW), if GPRS isdisabled in the non-EDGE-capable TRXs. The operator needs to define which TRXsare capable of EGPRSwith the parameter GPRS enabled TRX (GTRX) .

Only after the BSC has an update on the BTS parameters and other parameters indicating GPRS usage,does it count the number of default and dedicated GPRS time slots in the BTS and selects a TRX where itstarts to establish the GPRS territory.

The BSC can upgrade or downgrade the number of radio resources allocated for GPRS use according tothe varying needs of the circuit switched and GPRS traffic.



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Territory Method in BSC

TRX 1

TRX 2

BCCH TS TS TS TS TS TS TS

TS TS TS TS TS TS TSTS

CircuitSwitched

Territory

PacketSwitchedTerritory

Territory border moves based on Circuit

Switched and GPRS traffic load

DefaultGPRSCapacity

CDEFDedicatedGPRSCapacity

CDED

TS TS

AdditionalGPRSterritory

TS TS

MaxGPRS

CapacityCMAX

Refer to S11 Documentation:• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ Radio

resource management

The territory method is the same for GPRS and EGPRS. The BSC divides radio resources semipermanentlybetween circuit switched services and GPRS, thusforming two territories. The PCU uses the GPRS territory resources. The initial territories are formed on aBTS-to-BTS basis according to the operator-defined parameters. The BSC can later broaden the GPRSterritory based on the actual need and according to the requestsof the PCU.

The circuit switched services have priority over GPRS in channel allocation within common resources.GPRS releases its resources as soon as they are needed for circuit switched traffic. Within a cell, all theFull Rate and Dual Rate traffic channels are GPRS capable. GPRS capacity can be divided into three types:

• default GPRS capacity• dedicated GPRS capacity• additional GPRS capacity.

GPRS has a predefined set of resources which it can utilise whenthe circuit switched load allows. This is

referred to as the default GPRS capacity. Part of these default traffic channels can be reserved solely forGPRS and this means they are blocked altogether from circuit switched use. This is referred to as thededicated GPRS capacity. The user can modify these two capacities by using the respective parametersdefault GPRS capacity (CDEF)anddedicated GPRS capacity (CDED).Additional GPRS capacity is referred to with radio time slots that are above and beyond the default GPRScapacity and that the BSC has allocated for GPRS use according to the requests of the PCU. GPRSterritory size can be restricted by the user-modifiable parametermax GPRS capacity (CMAX) . There is aGPRS territory update guard time defining how often the PCU can request new radio time slots for GPRSuse.



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Dedicated GPRS capacity• part of the default resources can be reserved totally for GPRS =>

• these are blocked for CS traffic

Additional GPRS capacity• PCU can request for more then default capacity is in use =>• new resource request type for the radio resource manager of the circuit switched

services

Definition of territory parameter

Default GPRS capacity• predefined amount of resourceswhich GPRS can utilize when CStraffic allows it



The BSC calculates these defined resources from percentages to concrete numbers of radio time slotsbased on the number of traffic channel radio time slots (both blocked and working) capable of Full Ratetraffic in the TRXswith GPRS enabled (set with the parameter GPRS enabled TRX (GTRX) ). The superreuse TRXsin the Intelligent Underlay Overlay feature and the extended area TRXsin the Extended RangeCell feature are never included as available resources in the GPRS territory calculation. The calculation isas follows:

• the product of default GPRS capacity (CDEF) parameter and the number of radio timeslots is rounded down to a whole number.

• if default GPRS capacity (CDEF) parameter value is >0 but the rounded product equals0, then the territory size 1 is used

• default GPRS capacity (CDEF) parameter minimum value is 1.

• max GPRS capacity (CMAX) parameter minimum value is 1 (range 1- 100%).

The BSC starts to create the GPRS territory by first selecting the most suitable TRXsin the BTS accordingto its GPRS capability, TRX type, TRX configuration, and the actual traffic situation in the TRX. The preferBCCH frequency GPRS (BFG) parameter indicates if the BCCH-TRX is the first or the last choice for theGPRS territory or if it is handled equally with non-BCCH-TRXs.



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• Within a cell, all the Full Rate and Dual Rate traffic channels are GPRScapable.

• GPRS territory is a set of consecutive TSLs, excluding

GPRS Capable Traffic Channel

• TSLs that are not capable of full rate traffic

• non-TCH channels (BCCH, SDCCH)

• permanent half rate TSLs

• blocked TSLs

• TSL0 when BB Hopping is used

• transparent HSCSD calls.





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Capacity calculation rules:

• the product of default GPRS capacity (CDEF) parameter and the number of radio time slots (RTSL) is rounded down to a whole number.

• if default GPRS capacity (CDEF) parameter value is >0 but the roundedproduct equals 0, then the territory size 1 is used

• default GPRS capacity (CDEF) parameter minimum value is 1.

• max GPRS capacity (CMAX) parameter minimum value is 1 (range 1- 100%).

Exercise: Calculating GPRS radio capacity

BCCH SDCCH

TRX1

TRX2

TRX3GTRX=Y

GENA=Y

GTRX=N

Parameter:

Segment1:

TRX1 and 2:

TRX 3:

EGENA=N

CMAX=100

Exerciseseenextpage



Exercise: calculating GPRS radio capacity. Duration: approx. 10min

Given is a segment with three FR TRXs. The general GPRS parameter are shown at the slide.

1. How many RTSL are maximal GPRS capable? _________________________________________________________________________

2. How many RTLS are default and dedicated if CDEF=1 and CDED=1?Please draw them into thedelineation.

__________________________________

__________________________________

__________________________________

3. How many RTLS are default and dedicated if CDEF=100 and CDED=100? Please draw them into thedelineation.

__________________________________

__________________________________

__________________________________

4. How many RTLS are default and dedicated if CDEF=40 and CDED=20? Please draw them into thedelineation.

__________________________________

__________________________________

__________________________________

5. How many RTLS are default and dedicated if CDEF=40 and CDED=20 and for TRX3 the parameterGTRX is set =(GTRX=Y)? Please draw them into the delineation.

__________________________________

__________________________________

__________________________________

TRX1

TRX2

TRX3

TRX1

TRX2

TRX3

TRX1

TRX2

TRX3

TRX1

TRX2

TRX3



6-128338 v1 / 17.12.2003 / M. Weingart30

Support of PCCCH/PBCCH

PBCCH/PCCCH

PBCCH PPCH PDTCH PRACH

BCCH/CCCH

Common Channels

PAGCH

• More signalling capacity for (E)GPRS traffic

• Own neigbour cell list for (E)GPRS

• Own cell re-selection parameters for (E)GPRS:

C31/C32 cell selection criteria

– They are used to direct the GPRS traffic on the cells, which can serve EGPRS mostefficiently and interference free to CS traffic

– C31/C32 apply in cells using PBCCH/PCCCH, otherwise existing C1/C2 are used

• PBCCH is in the same TRX as BCCH

• PBCCH/PCCCH is hopping inside the

hopping group the timeslot belongs to(Base Band Hopping)



• Descriptions\ System Descriptions\ Nokia Base Station Subsystem Description\ Nokia BaseStation Subsystem solutions\ Nokia Base Station Subsystem data\ Support of

PCCCH/PBCCH

In general the packet control channel is configured in the cell with the same principles as other time slottypes. The restrictions on the location of channel are:

• The operator can define only one Packet Control Channel (MPBCCH) in the cell and it must belocated in the same TRX as the BCCH . The time slot of MPBCCH can be from RTSL 1 to 6.

• MPBCCH contains the following logical channels: PBCCH +PCCCH +PTCCH. In the currentimplementation the MPBCCH does not carry data traffic. The MPBCCH channel may be locatedoutside the GPRS territory.

MPBCCH is hopping inside the hopping group to which the timeslot belongs according to the parameters

defined for the hopping group. An MS attached to GPRS will not be required to monitor BCCH if a PBCCHexists. All system information relevant for GPRS and some information relevant for circuit switchedservices is in this case broadcast on PBCCH. When PBCCH exists in the cell the operator can define theGPRS capability of neighbour cells with the parameters in the adjacent cell object. Cell-level parametershandle MS-controlled cell re-selection.

In cases where the PBCCH/PCCCH channel is allocated to an EDGE TRX it acts as an EGPRS Abis L1synchronisation master channel for the GPRS channels of the BCCHTRX. The operator should not createthe PBCCH/PCCCH channel in network operation mode II, because CSpaging will not work on PCCCH innetwork operation mode II.



PBCCH The Packet Broadcast Control Channel is a downlink only channel for broadcasting packetdata specific system information messages.

PCCCH ThePacket Common Control Channel (PCCCH) consists of logical channels used for commoncontrol signalling for packet data.

PPCH The Packet Paging Channel is a downlink only paging channel usedto page the MS prior to

downlink packet transfer. The PPCH can be used for paging of both CS & PS data services.

PRACH The Packet Random Access Channel is an uplink only channel, which the MSsuse for uplinktraffic channel reservation and for obtaining the timing advance.

PAGCH The Packet Access Grant Channel is a downlink only channel used for resource assignmentduring the packet transfer establishment phase.

PDTCH The Packet Data Traffic Channel is reserved for the actual GPRS data transfer. A PDTCHcorresponds to the resource allocated to a single MS on one physical channel for user datatransmission. In multislot operation, one MS may use multiple PDTCHsin parallel forindividual packet transfer.



6-128338 v1 / 17.12.2003 / M. Weingart32

Routing Area

RAI = MCC+MNC+LAC+RAC

Rules:Routing Area Location AreaRouting Area Cell

PCU 1

PCU 0BTS

BTS

RA 1

BTS

BTS

RA 2

SGSN

BTS

BTS

RA n

LA

BTS

BSC

PCU n

LocationArea

RoutingArea

Cell


• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ RadioNetwork Management for GPRS in BSC

Mobility management in the GPRS network is handled in a similar way to the existing GSM system. Oneor more cells form a Routing Area (RA ), which is a subset of one Location Area (LA). The Routing Area isunique within a Location Area. As Routing Areas are served by SGSNs, it is important to keep in mind thenetwork configuration plan and what has been defined in the SGSN, before configuring the BSC side. OneRouting Area is served by one SGSN. When creating a Routing Areathe user identifies the obligatoryparametersmobile country code (MCC) , mobile network code (MNC) , locationarea code (LAC) ,and routing area code (RAC) . Routing Areas are created in the BSDATA. The MCC, MNC, LAC and RACparameters constitute arouting area identification (RAI).

In other words: The Routing Area and the BTS are linked logically together by the RAI. Routing Areas areused in the PCU selection algorithm which selects a serving PCU for the cell when the operator enablesthe GPRS traffic in the cell.

Optimal size of the RA:

to big: high paging signalling

to small: many routing area updates



6-128338 v1 / 17.12.2003 / M. Weingart33

Exercise: Read out GPRS RNW configuration


NSEI__________

BSC

BCSU=___ NSEI__________

RAC_____

BTS____

BTS____ RAC_____

BTS____

BTS____

RAC_____

BTS____

BTS____

LAC______

BVCI=_____

RAC_____

BTS____

BTS____ RAC_____

BTS____

BTS____

RAC_____

BTS____

BTS____

LAC______

RAC_____

BTS____

BTS____ RAC_____

BTS____

BTS____

RAC_____

BTS____

BTS____

LAC______MCC=_____

MNC=_____


BVCI=_____

BVCI=_____

BVCI=_____

BVCI=_____

BVCI=_____

BVCI=_____

BVCI=_____

BVCI=_____

BVCI=_____

Exercise:

Write down the used MMLcommands. Use the slide as template!

1 How can you read out existing Routing Area Codes (ZE...)?.

Command:___________________________________________________________________

2. Fill out Routing area identification (RAI =MCC, MNC, LAC andRAC) into the slide above.

3. Each active GPRS cell is represented via a BVC (BSSGP virtual Connection) in the NSE (Network ServiceEntity) and a NSE is specified via as one PCU. Find out which BTS –BVCI relationship is existing (ZEQ…)and which PCU is handling which NSEI (ZFW…).

Command:___________________________________________________________________

Command:___________________________________________________________________

4. Please connect the related BVCI and BTS bubbles in the slide.



6-128338 v1 / 17.12.2003 / M. Weingart34

EGPRS Coding Schemes

data coding

Radio interface block (1392 bits in 8-PSK)PCU BTS

BSCSGSN


• Descriptions\ Feature Descriptions\Data – IP-Multimedia\ (E)GPRS in BSC\ GPRS radioconnection control



6-128338 v1 / 17.12.2003 / M. Weingart35

8-PSK modulation

0, 1, 0

1, 1, 1

0, 1, 10, 0, 0

0, 0, 1

1, 0, 0

1, 0, 1 1, 1, 0

EDGE

8-PSK, 3bit/sym270.833 ksps

346 bits

69.2 kbps

GPRS

GMSK. 1bit/sym270.833 ksps

114 bits

22.8 kbps

ModulationSymbol rate

Payload/burst

Grossrate/ time slot

8-PSK



The idea behind increasing the data rates is the introduction of 8-PSK (Phase Shift Keying), a linearhigher order modulation in addition to the existing GMSK (Gaussian Minimum Shift Keying). An 8-PSK signal is able to carry three bits per modulated symbol over theradio path, while a GMSK signal carriesonly one bit per symbol. The carrier symbol rate (270.833 ksps) of standard GSM is kept the same for 8-PSK, and the burst length is identical to the current GMSK usingthe same 200 k carrier spacing. Withmulti-slot reservation, EDGE offers an evolution path for GSM to support medium rate multimediaapplications. The user can send more data per radio time slot with the same amount of air time used andoperators do not need to invest in another frequency band and license to offer higher data rate serviceslike mobile multimedia.



6-128338 v1 / 17.12.2003 / M. Weingart36

GPRS Coding Schemes

Nokia GPRSin BSS S11

• CS1 & CS2

ºImplemented in ALL Nokia BTS without HW change

• CS3 & CS4

ºWill not fit in normal 16kbit/s AbisTRAU frame

ºS11.5 future candidate

D a t a

E r r o r

C o r r e c t i o n

Coding

SchemeCS1

CS2

CS3

CS4

Data Rate

per TSL (kbit/s)9.05

13.4

15.6

21.4

More Data

=

Less Error

Correction





6-128338 v1 / 17.12.2003 / M. Weingart38

Dynamic Abis Allocation Introduction

• GSM/GPRS radio timeslot datacan be fitted into one 16 kbit/ssub timeslot in Abis-if

• EDGE introduces datathroughputs up to ca. 60 kbit/sover air

Â up to 5*16 kbit/s subtimeslots needed overAbis/radio timeslot

• BTS internal traffic can not be

fit into one D-bus (2 Mbit/s)

Â UltraSite has four D-buses

Abis capacity needs to be expanded (even up to 4 t imes higher)

Dynamic Abis AllocationDynamic Abis Allocation

¾1*16 kbit/s "Master" as fixed/radiotimeslot

¾1 …4*16 kbit/s "Slaves" dynamically asper needed/radio timeslot

Background


• Descriptions\ Feature Descriptions\ Data – IP-Multimedia\ (E)GPRS in BSC\ Dynamic Abis

• Optimise and Expand\ Capacity and Coverage\ Dynamic Abis Pool Handling

The Dynamic Abisfeature makes it possible to define common transmission resources for EDGE capable TRXssituated in the same AbisET-PCM. This common resource is called the Dynamic AbisPool. There arefixedly allocated transmission resources for Abissignalling links and traffic channels in AbisET- PCM asbefore but extra transmission resources needed for EGPRS calls are reserved from the dynamic Abis pool.



6-128338 v1 / 17.12.2003 / M. Weingart39

Nokia Dynamic Abis solutionPCU frame types

•PCU data frame

• used when TRX not in EDGE mode• only able to carry CS-1 and CS-2

•PCU master data frame• used when TRX is in EDGE mode• carries CS-1 or MCS-1 on its own and CS-2...CS-4

and MCS-2...MCS-9 with the help of slaveframe(s)

• includes pointers to the slave frames

•PCU slave data frame• carries additional data that does not fit in PCU

master data frames

•PCU random access frame

•PCU synchronisation frame

MCS-1 M

M

M

M

M

M

M

M

M

S

S

S

CS-4

CS-3

CS-2

CS-1

MCS-2

MCS-3

MCS-4

MCS-5

MCS-6

MCS-7

MCS-8

MCS-9

S

S

S

S

S

S

S

S

S

MM

M

M

S

S

S

S

S

S

S

S

CS-2CS-1

D

D EDGE TRX in non-EDGEmode or non-EDGE TRX

EDGE TRX inEDGE mode

D

M

S

PCU data frame

PCU master data frame

PCU slave data frame

+

+

+

+

+

+

+

+

+

+

+

retrans M


• Descriptions\ Feature Descriptions\ Data – IP-Multimedia\ (E)GPRS in BSC\ Dynamic Abis



6-128338 v1 / 17.12.2003 / M. Weingart40

Nokia Dynamic Abis solution

Fixed channels and EDAP

• For each GPRS radio timeslot on each EDGE TRX,one fixed 16-kbps channel is allocated on theAbisfor the transfer for PCU master dataframes.

• PCU slave data frames are allocated in acommon pool, the EDAP (EDGE Dynamic AbisPool).

• 12 PCM timeslots as the maximum size of EDAP.

• A master channel and its slave channels andtherefore the entire EDAP must be on the same

AbisPCM.

Abis PCM

TRX 1

TRX 2

TRX 3

OMU, TRX sigs

EDAP

TRX 4

TRX 5

TRX 6

TRX 7

TRX 8

TRX 9



NoteHowever, EDAP size is the same for both DL and UL directions, soit is not possible to set different EDAPsizes for DL and UL directions.

09a_(e)gprs handling in bss

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