CAPTURE DIVISION PACKET ACCESS - A NEW CELLULAR ACCESS ARCHITECTURE FOR FUTURE PCNS

The authors describe a new cellular access architecture, known as capt ure-division packet access: which is a packet-oriented architecture ab le to support the constant bit rate traffic and variable bandwidth on demand necessary for multimedia traffic. The approach integrates the m ultiple access and channel reuse issues to achieve a high degree of sp ectral efficiency, and presents general advantages even if used for de lay-constrained circuit-oriented traffic. Unlike CDMA and TDMA, wherei n the effective data rate of each connection is typically a small frac tion of the total radio channel allocated for PCN, the CDPA approach a llows each user to access the entire channel, if necessary, for brief periods of time (packet access). Spectrum sharing is accomplished by e xploiting the different path losses suffered by the various signals as they appear at the base stations (the capture effect), with co-channe l interference abated through time diversity (colliding users do not s uccessively retry in the same time interval). Results suggest that aba ting co-channel interference by random retransmission may be more effe ctive than spatial isolation at cells using the same channel, as is us ual in FDMA/TDMA systems.