GPRS/EDGE Basics / knowledge sharing

Editor's Notes

• #8: Mobility Management = Attach & Detach, RAU, Authentication & Ciphering, Paging, P-TMSI Session Management = PDP context activation, deactivation and modification
• #9: Gc interface not supported by Nokia
• #10: - Gn is open - Gb and Gi are open - Gc not supported by Nokia
• #11: 22,5° offset to avoid origo crossing! Peak to average ratio 3,2 dB Min to max ratio 16 dB.
• #12: Why avoid zero-Xing? Zero-Xing will lead to any possible interpretation of phase state from the decoder on the receiver side, so avoiding zero-Xing it’s a way to reduce the risk of misinterpretation of the right bit combination. Any combination from star to solid dot is possible as well as from solid dot to star. All of this combinations avoid the zero-Xing.
• #14: Back-off needed due to linearity requirements.
• #19: This slide is a recall of GPRS coding scheme structure for comparing GPRS and EGPRS coding schemes on the next slides.
• #20: Emphasize Code Rate and Header Code Rate… Code rate: Radio block data part before coding /Radio block data part after puncturing, e.g. for MCS-7: 468/612=0,76 Header code rate: Header part before coding/Header part after coding & puncturing, e.g. for MCS-9: 45/124=0,36 for MCS-4: 36/68=0,53 Note: header part here does not comprise USF & SB
• #21: Header and payload is separated in EGPRS. (Those are not separated in GPRS!) General idea of how a piece of payload information is handled when transmitted "Additional info" consits of Info whether this is the last block or not Block check sequence (first step of coding procedure) Tail bits (needed in coding) Header part consits of Resource usage To whom this block How should be acknowledged Is power reducted Which coding & punturing is used for data Header type How many radio blocks are still to come etc… Three different up- and downlink header types for EGPRS (MCS-7, 8, 9, MCS-5, 6, MCS-1, 2, 3, 4)
• #22: GPRS MS CLASS The purpose of the definition of the GPRS MS Classes is to enable the different needs of the various market segments to be satisfied by a number of MS types with distinct capabilities. CLASS A: Supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation and simultaneous traffic. CLASS B: Simultaneous traffic shall is not supported. The mobile user can make and/or receive calls on either of the two services sequentially but not simultaneously. The selection of the appropriate service is performed automatically, i.e. an active GPRS virtual connection is put on hold, if the user accepts an incoming circuit switched call or establishes an outgoing circuit switched call. CLASS C Supports only non-simultaneous attach. Alternate use only. If both services (GPRS and Circuit Switched) are supported then a Class C MS can make and/or receive calls only from the manually or default selected service, i.e., either GPRS or Circuit Switched service. The status of the service which has not been selected is detached i.e., not reachable.
• #25: EDGE will provide the solution for operators wanting to offer personal multimedia services early and who need to increase the data capacity in their GSM network. EDGE will not replace existing investments or services but will upgrade them to a highly competitive level through gradual investment. EDGE rollout can satisfy increased data demand and produce increased revenues by first launching an EDGE service in urban and office environments for business users and then providing wider area coverage as private usage takes off. EDGE offers data services comparable to 3rd generation prior to UMTS deployment. EDGE is especially valuable for operators that do not deploy UMTS.
• #27: The Dynamic Abis pool must be created on the PCU where the NSEI (used for the BTS) is defined. The Dynamic Abis pool must also be created on the same ETPCM where the TRX signaling is located. Note that GPRS territory downgrade is performed during EDAP creation. To enable EGPRS in a cell the dynamic Abis pool has to be created first and then create a TRX which uses the pool When the TRX using the dynamic Abis pool is created, GPRS must be disabled in the cell GPRS must be enabled in the cell (parameter GENA set to Y) and EGPRS enabled in the BTS (parameter EGENA set to Y) in order to enable EGPRS traffic in the BTS If GENA is set to N then EGPRS traffic is also disabled
• #28: EDAP in BSC must be inside the TSL boundaries defined in the BTS side: This requirement has to be taken into account also when modifying EDAP size or changing the first and/or the last timeslot. The timeslot indexes in the BSC and BTS also have to match, regardless of how the timeslots are routed through the transmission network. In other words, when modifying EDAP the size of EDAP in the BTS has to be the same as the size of EDAP in the BSC.
• #30: No Priority on CCCH S9 Shared S10 Dedicated PBCCH (PCCCH)
• #33: Ask trainees about expected durationof READY and STANDBY Timers (I.e. 44 seconds and 1-2 hours)… STANDBY timer should be 2x > Periodic RA Update Time. In IDLE mode no GPRS Mobility Management In STANDBY mode Routing Area Update are performed In READY mode a Cell Update is performed when the MS changes the cell
• #38: QoS is like type of APNs (Access Point Names) available to the user.
• #43: TFI - temporary flow identity, PACCH - Packet Associated Control Channel used for Acknowledgements.
• #46: 7 UL because of 3 bits for USF (8 - 1 reserved = 7)
• #47: Not like a mux but a "tolken / round robin" scheme