Showing posts with label EGPRS. Show all posts
Showing posts with label EGPRS. Show all posts

PACKET DATA APPLICATIONS



The WCDMA/GSM GPRS system supports end-users wishing to access the Internet and Intranets using a WCDMA UE or GPRS MS as the connecting device. Some examples of user applications enabled by 3G are given below:

·          Video Telephony and Video Conferencing
·          Broadband Web Browsing and Multimedia Streaming; for  example, video clips, news on demand and music
·         Mobile Broadband
·          Multimedia Messaging (voice mail with pictures)
·          Location-based Servic


Additionally, all data services enabled by 2.5G technologies will also be available. For example, some horizontal applications enabled by 2.5G are:
·          E-mail
·          Internet chats
·          File transfer using the File Transfer Protocol (FTP)
·          Point of sale (credit card readers)
·         Database searches
·         Two-way messaging

On-Demand PDCHs

General on-demand PDCH allocation as a new PSET (not for individual MS support), can be performed only in the BCCH frequency band if the parameter MBCRAC is set to 0 (default value). To allow general on demand allocation of PDCHs in other bands in a cell MBCRAC must be set to 1 or 2.

Extension of an already existing on-demand PSET is however generally allowed regardless of the MBCRAC setting.

The maximum number of on-demand PDCHs per channel group can be limited by the parameter ODPDCHLIMIT.
At allocation of on-demand PDCHs, the requested number of channels (or as many as available and allowed) are selected within the allowed frequency band(s) and subcell(s) according to the following algorithm:
1 In the case of adding PDCHs to a PSET, then select the TCHGRP where the other PDCHs in the PSET are located. Then proceed to step 10.

2 Among all TCHGRPs, select the TCHGRPs that have the best idle rank value for E-TCH.

3 Among these TCHGRPs, select the TCHGRPs that have the best idle rank value for G-TCH.

4 Among these TCHGRPs, select the TCHGRPs that have the best idle rank value for B-TCH.
5 Among these select the TCHGRP(s) that fulfils the operator chosen strategy regarding non hopping TCH on the BCCH frequency, according to parameter CSPSALLOC.

6 If the function Idle Channel Measurements is active, select among these TCHGRPs the TCHGRPs with the lowest interference level. (This refers to the channel with the highest interference level within the TCHGRP.)

7 If frequency hopping is used, select among these TCHGRPs the TCHGRPs hopping over as many frequencies as possible.

8 Among these TCHGRPs select ones in the non BCCH frequency band first, and the BCCH band as second choice if the prerequisites mentioned above will admit this.

9 If Packet Data in Overlaid subcell is used, select among these TCHGRPs the TCHGRPs in the preferred subcell according to the parameter SCALLOC.

10 Among these TCHGRPs, select the first found TCHGRP and allocate as many PDCHs as requested (or as many as possible and allowed according to the parameter ODPDCHLIMIT, if less).


Cell level Traffic Load Counters for EDGE Evolution


TBFDCDLCAP : Number of downlink TBFs where the MS is capable of using dual carriers.

TRAFDCDLTBF :  Number of downlink TBFs, in EGPRS mode, reserved on dual carriers.

MAXDCTSDL : Maximum possible number of time slots reservable for MSs on downlink TBFs in EGPRS mode, reserved on dual carriers.

MUTILDCDL : Sum of percentage shares of reserved time slots for all EGPRS mode downlink TBFs reserved on dual carriers related to the maximum possible reservable time slots.

TRAFEEVOSCAN : Number of scans for the counters in this object type. This counter is only valid for counters in object type TRAFEEVO.


TSDCDL: Number of time slots with one or more uplink or downlink TBFs currently reserved on dual carriers.

GPRS/EGPRS Traffic Load counters for the uplink per cell


TRAFFULGPRSSCAN Total number of scans (accumulations).

TBFULGPRS Accumulated number of Basic and GPRS mode UL TBFs (active users), for all types of traffic, including effective streaming PDCH and PDCH used for EIT, in the cell.

TBFULEGPRS Accumulated number of EGPRS mode UL TBFs (active users), for all types of traffic, including effective streaming PDCH and PDCH used for EIT, in the cell.

ULBPDCH Accumulated number of B-PDCH that carried one or more UL TBFs of any mode in the cell (a B-PDCH used on the UL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

ULGPDCH Accumulated number of G-PDCH that carried one or more UL TBFs of any mode in the cell (a G-PDCH used on the UL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

ULEPDCH Accumulated number of E-PDCH that carried one or more UL TBFs of any mode in the cell (an E-PDCH used on the UL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

ULTBFPBPDCH Accumulated number of simultaneous UL TBFs of any mode per used B-PDCH in the cell. Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

ULTBFPGPDCH Accumulated number of simultaneous UL TBFs of any mode per used G-PDCH in the cell. Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

ULTBFPEPDCH Accumulated number of simultaneous UL TBFs of any mode per used E-PDCH in the cell. Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT. With Flexible Abis the counter values will be slightly higher.

ULACTBPDCH Accumulated number of B-PDCH that carried one or more active UL TBF of any mode in the cell (an active B-PDCH on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.


Ericsson Counter : GPRS/EGPRS Traffic Load counters for the downlink per cell.


TRAFFDLGPRSSCAN Total number of scans (accumulations).

TBFDLGPRS Accumulated number of Basic and GPRS mode DL TBFs (active users), for all types of traffic, including effective streaming PDCH and PDCH used for EIT, in the cell.

TBFDLEGPRS Accumulated number of EGPRS mode DL TBFs (active users), for all types of traffic, including effective streaming PDCH and PDCH used for EIT, in the cell.

DLBPDCH Accumulated number of B-PDCH that carried one or more DL TBFs of any mode in the cell (a B-PDCH used on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

DLGPDCH Accumulated number of G-PDCH that carried one or more DL TBFs of any mode in the cell (a G-PDCH used on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

DLEPDCH Accumulated number of E-PDCH that carried one or more DL TBFs of any mode in the cell (an E-PDCH used on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

DLTBFPBPDCH Accumulated number of simultaneous DL TBFs of any mode per used B-PDCH in the cell. Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

DLTBFPGPDCH Accumulated number of simultaneous DL TBFs of any mode per used G-PDCH in the cell. Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

DLTBFPEPDCH Accumulated number of simultaneous DL TBFs of any mode per used E-PDCH in the cell. Valid for all types of traffic, including effective streaming PDCH and PDCH
used for EIT. With Flexible Abis the counter values will be slightly higher.

DLACTBPDCH Accumulated number of B-PDCH that carried one or more DL active TBFs of any mode in the cell (an active B-PDCH on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

DLACTGPDCH Accumulated number of G-PDCH that carried one or more active DL TBFs of any mode in the cell (an active G-PDCH on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.


DLACTEPDCH Accumulated number of E-PDCH that carried one or more active DL TBFs of any mode in the cell (an active E-PDCH on the DL). Valid for all types of traffic, including effective streaming PDCH and PDCH used for EIT.

PDCH: Packet Data Channel in GPRS

PDCHs may also be used by TBFs in Dual Transfer Mode (DTM). The DTM TBFs may either use PDCHs already allocated for normal GPRS/EGPRS traffic or trigger allocation of additional PDCHs that then can be used for normal GPRS/EGPRS traffic too. Some PDCHs can later be returned to the CSD when they are no longer needed, or when CS traffic or Abis demand requires it.

There are different types of PDCHs; dedicated PDCHs, semi-dedicated PDCHs and on-demand PDCHs.



Dedicated PDCHs:
The number of dedicated PDCHs in a cell is set by the operator. These PDCHs are allocated at configuration from the CSD to the PSD for GPRS/EGPRS traffic and can then not be pre-empted by CS traffic. A GSL resource and an Abis resource is allocated at the time of allocation. The number of dedicated PDCHs can only be decreased by the operator.

Semi-dedicated PDCHs:
The number of semi-dedicated PDCHs in a cell is also set by the operator. These PDCHs are allocated at configuration from the CSD to the PSD for GPRS/EGPRS traffic and cannot be pre-empted by CS traffic. The number of semi-dedicated PDCHs can only be decreased by the operator. Semi-dedicated PDCHs will be activated first when there is need for more PDCHs for PS traffic, that is the GSL resource is not allocated until needed. The Abis resource is not allocated until needed either if the channel has a flexible Abis resource, When there is no longer any traffic need for a semi-dedicated PDCH (no TBF is reserved on it), it will be put in the PSD idle list (PIL). Eventually the GSL resource and the Abis resource (if a TCH with flexible Abis is used) will be returned to the respective pool.

On-demand PDCHs:

On-demand PDCHs are allocated from the CSD only when there is need for more PDCHs for PS traffic. At on-demand PDCH allocation also the GSL resource is allocated. The Abis resource is also allocated if the channel has a flexible Abis resource,  When there is no longer any traffic need for an on-demand PDCH (no TBF is reserved on it), it will be put in the PIL. Eventually the GSL resource and the Abis resource (if a TCH with flexible Abis is used) will be returned to the respective pool and the PDCH will be deallocated from the PSD and returned to the CSD. On-demand PDCHs can also be pre-empted by CS traffic.

Active Queue Management (AQM):




Active Queue Management (AQM) is a queue management feature for the downlink. For applications using TCP/IP as transmission (e.g. FTP, web browsing, email), it is important with a rapid feedback of the radio link data rate to the TCP/IP protocol. Feedback of the radio link data rate is reported to TCP/IP by discarding IP-packets. In this way the TCP/IP protocol will faster adjust its send rate according to the radio link capacity and TCP slow-starts are avoided. If the feature “QoS and Scheduling” in BSC is active (R97 QoS and/or R99 QoS), the queue management feature is applied to Interactive class and Background class data. The queue management feature is not applied to signalling messages, SMS, LLC acknowledged mode data, EIT data or Streaming class data when QoS is active. For SMS, signalling messages, LLC acknowledged mode data, EIT data and Streaming class data a maximum buffer is set and when the buffer is overflowed packets are discarded starting from front of the buffer.

If the feature “QoS and Scheduling” in BSC is passive, the queue management feature is applied to all payload data but not to signalling messages, SMS or LLC acknowledged mode data. For LLC acknowledged mode data and data not handled by AQM a maximum buffer is set and when the buffer is overflowed packets are discarded starting from front of the buffer.

EGDE - Enhanced Data rates for GSM Evolution


(E)GPRS Network Infrastructure







How to calculate what
          No. of EGPRS resources used in 1 sector * No. of sectors : 2 x 3
           No. of time slot/sector * no of time slot used for EDAP :- 2 * 3 = 6
          So total time slots per site 6 + 6 = 12
          1 NSEI support 256 time slot with upgrade % as 10 so total no of time slots which can be equipped is 256 - 10% of 256 = 230.4 ~ 230
          So no. of sites per NSEI is 230/12 = 19.16 ~ 19
          So no NSEI required / BSC :  100 / 19 = 5.2 +1 (for future use) ~ 6
          2 NSEI supports 1 BCSU so no. of PCU required : 6/2 = 3
          No. of NSEI required is equivalent to the no. of Gb link = 3
          On 1 E1 we can get 31x64 = 1984 , so access rate can be given by 1 E1 = 1984/ access rate (256) = 1984 / 256  ~  7

Transmission requirement for EGPRS coding schemes in Abis interface






EDGE modulations

  
Scheme
Modulation
Maximum rate [kb/s]
MCS-9


8PSK
59.2
MCS-8
54.4
MCS-7
44.8
MCS-6
29.6 / 27.2
MCS-5
22.4
MCS-4


GMSK
17.6
MCS-3
14.8 / 13.6
MCS-2
11.2
MCS-1
8.8

 
 EDAP utilization
          6 EGPRS RTSLs (Dedicated + Default territory)
           50 % utilization assumed (3 Data Erlangs traffic)
           On average 3 RTSLs used





          RTSLs use MCS7 (44.8 kbit/s) with average C/I=13dB and throughput 30kbit/s
           Effective data rate factor excluding retransmissions over the air-interface is 30/44.8 ~ 0.7
           Slave group utilization is 0.7*0.5= 0.35