ll (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hil Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Future Enhancements and Services Chapter 11 Table 11-1 Modulation Gross Rate Radio Interface Rate The Six Coding Service (In Kbps) (In Kbps) Schemes for EGPRS EGPRS PCS-1 0.326 8-PSK EGPRS PCS-2 0.496 8-PSK EGPRS PCS-3 0.596 8-PSK 41.25 EGPRS PCS-4 0.756 8-PSK EGPRS PCS-5 0.829 8-PSK 57.35 EGPRS PCS-6 8-PSK Six coding schemes have been specified for eight-phase shift keying (8-PSK) modulation with regards to EGPRS. These can be seen in Table 11-1. It is assumed that each communication link will be able to choose the modulation and coding combination that achieves the highest throughput for that particular link quality. For example, users with a low channel-to-interference (C/I) ratio will be able to perform a link adaptation towards Gaussian minimum shift keying (GMSK) as opposed to 8-PSK. This link adaptation between GMSK and 8-PSK should be seamless because both modulation schemes utilize the same symbol rate of 270.833 kilo symbols per second (Ksps). Enhanced Data Rates for GSM Evolution (EDGE) Beyond GPRS, EDGE takes the cellular community one step closer to UMTS. It provides higher data rates than GPRS and introduces a new mod- ulation scheme called 8-PSK. The TDMA community also adopted EDGE for their migration to UMTS. The data rates allocated for EDGE start at 384 Kbps and above as a second stage to GPRS. EDGE uses the same mod- ulation techniques as many of our existing TDMA infrastructures by using GMSK 8-PSK. Moreover, EDGE uses a combination of Frequency Division Multiple Access (FDMA) and TDMA as the multiple access control methods. If we look at this from an OSI stack model, EDGE uses FDMA and TDMA Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hil Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Future Enhancements a