The 3 TDMA upgrade options include HSCSD, GPRS, EDGE.

HSCSD:

• High speed circuit switch data allows a single mobile user to the consecutive user timeslots in GSM standards.

• Increase the available applicable data rate to 14.4 kbps.

• HSCSD is ideal for dedicated streaming internet access or real-time interactive web sessions and simply requires the service provider to implement a software change at existing GSM base stations.

GPRS:

• General packet radio service is a packet based data network which is well suited for non real time internet usage, including the retrieval of email, faxes & asymmetric web browsing where user downloads much more data than it uploads.

• GPRS supports multi user network sharing of individual radio channel and time slots.

• Requires operator to install new routers and internet gateways at base station along with new software. No new base station nad RF hardware is required.

EDGE:

• EDGE which stands for Enhanced Data rates for GSM for Global Evolution is more advanced upgrade to the GSM standard and requires additional hardware and software at existing base stations.

• It introduces a new digital modulation format, 8-PSK (Octal Phase Shift Keying) which is used in addition to GSM and GMSK modulation