GPRS Software Protocol

8/6/2019 GPRS Software Protocol

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Gprs software or General Packet Radio Service is apacket switched technology, based on GSM. Theradio and network resources of gprs software are

only accessed when data actually needs to betransmitted between the gprs software mobile userand the gprs software network. This data is divided

into packets and is then transferred via the radioand core gprs software network.


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Conty B etween alternating transmissions, no gprs software

network resources need to be allocated. gprs softwareoffers up to 115 kbps, depending on the networkavailability, channel coding scheme and terminalcapability. This increase in speed in gprs software withrespect to GSM is achieved by using more than onetimeslot of the TDMA frame. Due to the packet

switched characteristics of gprs software the allocationof the available timeslots may vary from one instant tothe next (e.g. it may have 8 timeslots at one time and 4later on).


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y The General Packet Radio Service (GPRS) is a new value added service that allows information to be sent

and received across a mobile telephone network. Itsupplements today's Circuit wireless Switched Dataand Short Message Service.


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y Timeslot building requires new functionality on themobile side. Gprs software needs a Serving gprs

software support node (SGSN), a Gateway gprssoftware support node (GGSN) and a charging gateway function to support packet switched transactions. Thepacket switched traffic is separated from the circuitswitched traffic at the B SC/PCU and diverted to thegprs software core network. To support point-to-multipoint features, a point-to-multipoint ServiceCenter (PTM-SC) needs also to be added.


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y Depending on the environmental radio conditions,one of the four coding schemes (CS1, CS2, CS3, CS4)

can be selected. CS1 and CS2 offer good error detectionand correction with low throughput; in the first step of gprs software only these two techniques may be used.CS3 and CS4 provide higher throughputs but havelittle or no error correction capabilities.


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y Table 1 shows the different data rates that can beachieved with the different coding techniques.


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y B ecause gprs software is packet switched traffic, newprotocols and channel types are required. In gprs

software the mobile device is permanently attached tothe network, providing a virtual connection withoutcost and data transfer (GPRS-Attach). gprs software- Attach procedure is executed whenever a gprs softwareenabled mobile station is switched on and needs toinform the network about its presence.


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y The two peers of a gprs software attach procedure arethe mobile station (MS) and the Serving gprs software

Support Node (SGSN). Depending on the availability of the packet Common


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y Control Channel (PCCCH), the gprs software-Attachprocedure may be executed on Circuit Common

Control Channel (CCCCH).y Figure 1 shows the gprs software system architecture,

indicating new functionality required for phase2+operation.


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y Configurations:y Layer 1. Radio gprs software. This layer includes the

following GSM phase2+ ETSI standards:y GSM 05.02 Access & Multiple Multiplexing.

GSM 05.03 Interleaving Code/Decoder Channel.GSM 05.04 Demodulator and Modulator.

GSM 05.05 Receiver and Transmitter.GSM 05.10 Synchronization.


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y Layer 1.Vocoders gprs software. This layer includes thefollowing GSM phase2+ ETSI standards:

y

GSM 06.10 Full rate speech transcoding.GSM 06.20 Half rate speech transcoding.GSM 06.60 Enhanced Full rate speech transcoding.GSM 06.90 Adaptive multi-rate speech transcoding.

GSM 06.93 Discontinuous transmission for AdaptiveMulti-rate.


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y Layer 2 & 3 GSM phase 2+ ETSI standards:y GSM 03.09 Hand-over.

GSM 03.22 Link control.GSM 04.04 PROTOCOLS Layer 1.GSM 04.05 PROTOCOLS Layer 2.GSM 04.06 PROTOCOLS Layer 2.

GSM 04.07 PROTOCOLS Layer 3.GSM 04.08 PROTOCOLS Layer 3.GSM 05.08 Power control.


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y EGPRS (also call EDGE) is an enhanced version of gprssoftware, that uses a different modulation technique, 8

PSK, that has a spectral efficiency of 3 bits/s/Hz. gprssoftware uses GMSK, with a spectral efficiency of 1bit/s/Hz.


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y GPRS Software will provide an important boost tomobile data usage, because of its flexible feature set,

its latency, efficiency and speed.y The following text, in the links below, provides VOCAL

datasheet as a source of background informationabout gprs software.

Documents

GPRS Software Protocol