The effects of capture on the average system throughput and delay performance of slotted Aloha have been analyzed for slow and fast Rayleigh fading radio channels. A short-range multipoint-to-base-station packet radio network is considered. Several different definitions of capture are considered where the bit error probability is used as a criterion. The authors show that larger capture effects and thus improved network performance can be achieved with proper choice of modulation and that the use of space diversity and/or simple error-correcting codes improves capture. It is concluded that the inverse distance variability of the received signal is the main reason for the capture effect. The Rayleigh fading alone yields a very small contribution in terms of throughput. Numerical results are presented for a slotted Aloha system with 50 users. It is found that the maximum average throughput can be increased from about 36% to almost 60% by using coding and diversity.
|Original language||English (US)|
|Title of host publication||Unknown Host Publication Title|
|Number of pages||5|
|State||Published - Dec 1 1987|
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