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.

Popular posts from this blog

SCFT - Single Cell Function test

-
Single Cell Function test SCFT is for verifying whether individual BTS works well or not, by making a single cell function test of BTS hardware and software. Essential items to be tested are as follows: 1) BTS Transmitter Output Measurement Test 2) Initial parameter establishment (Pilot PN/System ID/Site ID/Frequency, Neighbor List) 3) Call Origination and Termination Test 4) Softer Handoff Test/Antenna installation check (Direction, Tilt, Transmission Line) 5) Single Cell Coverage Test 6) Noise Floor Test 7) Parameter check.
Read more

Troubleshooting for GSM KPIs (SD Block & SD Drop)

-
KPIs to be monitored: ·             SD Blocking ·             SD Drop SDCCH Channel: ·    SDCCH channel is a dedicated channel which is using for LAC updation, Call Setup, SMS in Ideal mode. It works in UL & DL SD Blocking: ·    SD Blocking means that you are not getting SD resource for the call origination. When MS connects with Network then RACH and AGCH are provided. After AGCH, SDCCH is provided but if SDCCH is not provided at this time due to some problem or due to unavailable of SD by BSC. KPI Formula in Ericsson: ·             SDCCH CONGESTION = (CCONGS / CCALLS) * 100 ·             CCONGS - Congestion counter. ·  ...
Read more

PS core network

-
Image
The PS core network consists of two parts, the traditional General Packet Radio Service (GPRS) core network and the new Evolved Packet System (EPS) core network. The PS core network connects mobile subscribers to Packet Data Networks (PDNs) such as the Internet, corporate networks or operator services networks.  a functional overview of the PS core network. Logical entities and interfaces are shown in black and form a 2G/3G network, while the blue boxes and lines in Figure  show the LTE/EPC related parts. The LTE/EPC network can be regarded as an extension and evolution of existing 2G/3G networks. From a node implementation perspective, there is no strict border between the two networks. The corresponding logical entities of GPRS and EPS networks can be deployed concurrently in Ericsson PS core nodes, such as the SGSN-MME and EPG; these are marked in red. In addition, Ericsson GPRS nodes can be upgraded with EPC functionality by software only. Network evolution i...
Read more