Abstract--One of the most important design issues in cellular systems design to have as many

users for a given area, and to do it as cheaply as possible.Current handsets require extensive processing to achieve acceptable performance and reliability for voice communication, which means these handsets are expensive. With the next generation of cellular systems, data transmission will be nearly as important as voice, but data does not require constant connections and can withstand more errors since data can be retransmitted, so new handsets can be made which take advantage of this fact. One method for reducing complexity is to directly spread the data in a CDMA system, thus removing the costly Viterbi decoder and memory intensive interleaver/deinterleaver. We investigate the performance of a direct spread version of IS-95 with the original IS-95, and showthat under certain conditions the direct spread version performs better than IS-95.

Introduction: The difference beween the IS-95 CDMA system and the diect spreading CDMA system is DSCDMA doesn't employ error correction coding. IS-95 uses conolution coding which also consists of conolution decoder at the receiver.

In this project I am going investigate the performance of direct spreading by comparing the current CDMA standard IS-95 ,to a version of IS-95 of which uses direct spreading.

Communication," in Wireless Communications TDMA vs. CDMA (S.G.

Glisic and P.A. Leppanen, Eds.), Kluwer Academic Publishers, 1997, pp.

415-446.