Symbian on GPRS

Overview

GPRS (General Packet Radio Service) is an enhancement of core GSM (Global System for Mobile Communications) networks, that allows the rapid transfer of data bundled into 'packets', separate from voice or data call circuits.

A 2.5G stepping stone to 3G networks and services, GPRS is a non-voice service that acts as a supplement to existing Short Messaging Service (SMS) and Circuit Switched Data (CSD) services.

With GPRS, data is transfered in packets and the set-up time is much shorter. GPRS supports flexible data transmission rates by aggregating several radio channels. Though the theoretical maximum is 171.2 Kbps, typical throughput is up to 20 or 30 Kbps.

Offering a continuous 'always on' connection, GPRS is suited to be charged by the amount of data transfered rather than by connect time.

GPRS services open a new door for mobile phones, offering true 'mobile Internet' possibilities. GPRS networks and services show today some of the possibilities of the 3G networks to come.

GPRS and the user experience

GPRS will enable users to experience mobile communications in a more integrated way than is currently possible. Mobile phones will be able to remain continuously online, initiating communication without the overhead of setting up a data call. With GPRS online connection will be more usable, with less delays while data transfer occurs.

Being continuously online has several advantages:

email is delivered without having to make a connection to collect it
messages can be pushed to the user to inform them of important events and information voice calls can be made at the same time as the user accesses data (with a class A phone)
applications can be used in a shared environment, and data sharing is made easier - effectively like being connected to a LAN (Local Area Network).
applications can be downloaded and installed, allowing software updates to be received etc.

Why GPRS?

GPRS is a stepping stone to the future.

Network operators are moving towards a goal where network speeds will enable live audio and video to be transmitted over a mobile network. This high-speed data transmission capability will enable many of the services outlined above. However, building the infrastructure will take time - a fact that is unacceptable to the network operators, as they want to create the mobile community immediately. This is where GPRS comes into play.

GPRS is not fast enough for live video, but is fast enough to create the business demand for true third-generation (3G) network applications. As GPRS runs over the existing GSM networks with the addition of two network nodes, the rollout of GPRS services can be achieved quickly and inexpensively in comparison with true 3G networks.

This paves the way for the 'always on' user experience, something which has not been available with circuit-switched networks. Thus users will get the feel of what later 3G networks will be delivering, and the demand and uptake will be faster and easier for the user to handle.

In addition, GPRS uses available airwaves more efficiently than circuit-switched data (CSD) connections, as users effectively share available resources rather than making a direct connection as per a data call.

Network operation mode and phone classes

The Network Operation Mode, or NOM, is responsible for the capabilities of a GPRS network, while the class indicates the mobile phone capabilities. On NOM 1 networks, mobile phones with the right capabilities can have simultaneous circuit- and packet-switched connections. On NOM 2 networks, mobile phones can remain attached to the GPRS networks when in a voice call but they can't transmit data at the same time. On NOM 3 networks, mobile phones can either establish a packet-switched data connection or a circuit-switched voice one but they need to disconnect from one to establish another.

Class A phones can make full use of NOM 1 networks: they can use circuit-switched voice and GPRS data services at the same time. Class B phones can register circuit-switched voice and packet-switched data services at the same time but may only use one at a time. Should the user receive a call while on the internet, they can take the call and GPRS service will be suspended, resuming once the voice call is ended. Resuming GPRS service is much faster than re-establishing a data call. Class C phones can only register for packet-switched data or for circuit-switched voice services; if the user chooses GPRS, then they will be totally unavailable for GSM calls and reciprocally.

End-users will initially have access to Class B mobile phones, which are able to make and receive calls while simultaneously being registered with GPRS services - GPRS services will automatically be suspended and resumed at the end of the call. Class B phones only support one active service at a time - GSM (voice, fax or data) or GPRS (data) - though both services can be registered with the network and the phone can switch automatically back and forth. However, should the user roam to a network area that is NOM III, their Class B phone will effectively be working as a Class C phone.

New applications designed to run in an online environment will be developed to take advantage of GPRS and 3G networks. The user may well experience a 'blurring' of applications whereby they won't need to switch task nearly at all.