GPRS (General Packet Radio Services)

Here, after GSM, before I go to 3G world, thought to spare some time to get clear idea about GPRS. Here, you can find few things about GPRS.

GPRS is a data service for GSM. GPRS is a packet switched mobile data service, it is wireless packet based networks to carry data,

In GPRS, data transferred is encapsulated into short packets with a header containing the origin and destination address.
The packets are then sent individually over transmission network. Packet originate from one user can take different route through the network to the receiver. Packet originate from the many users can be interleaved. So, that transmission capacity is shared. No pre-set time slots are used. Instead network capacity is allocated when needed and released when not needed. This is called statistical multiplexing. In contrast to GSM voice or circuit switched data.

GPRS upgrades GSM data service to be more compatible with LANs, WANs and Internet. GPRS uses radio resources only when the data is to be sent or received.

While the current GSM system was originally designed for voice sessions, the main objective of GPRS is to offer access to standard data networks such as TCP/IP. These networks consider GPRS to be normal sub-network.

In terms of architecture point of view, there are two new important entities in GPRS. GGSN (Gateway GPRS support Node), and SGSN (Serving GPRS Support Node). It also has few additional functionality in BSS.

SGSN:
The SGSN provides subscriber management, mobility management, as well as session management for any mobile GPRS user that has been associated with this SGSN. In order to achieve this task, the SGSN holds interfaces to the GSM subscriber databases: HLR, VLR, AUC and EIR. The SGSNs also hold the interfaces to the BSSs, and provides the authentication and encryption services for secure transmission of user data.

GGSN:
The GGSN provides connectivity to external Packet Data Networks (PDNs).
The GGSN also provides address translation services. Rate adaptation services between the GBS and external networks may also be included in the GGSN. The Border Gateway
provides connectivity to another Operator’s GPRS network.

New interfaces will be required to connect the new entities to the existing GSM network elements. These interfaces will be pre-fixed with the character ’G’ and will support both traffic and signal connections.

The Benefits that GPRS provides compared to Circuit switched data:
The data transferred is encapsulated into short packets with a header containing the origin and destination address. The packets are then sent individually over the transmission network. Packets originating from one user may take different routes through the network to the receiver.

Packets originating from many users can be interleaved, so that the transmission capacity is shared. No pre-set time-slots are used. Instead, network capacity is allocated when needed and released when not needed. This is called statistical multiplexing, in contrast to static time division multiplexing. In static time division multiplexing, time-slots are reserved for one user for the length of the connection regardless of whether it is used or not, as with PCM lines and GSM voice and circuit switched data.

GPRS upgrades GSM data services to be more compatible with LANs, WANs and the Internet.

GPRS uses radio resources only when there is data to be sent or received, and so is well adapted to the very bursty nature of data applications.

Furthermore, it provides fast connectivity and high throughput. While the current GSM system was originally designed for voice sessions, the main objective of GPRS is to offer access to standard data networks such as TCP/IP.

Stay tuned for 3G now:-))