Capacity of wireless CDMA networks supporting integrated voice/video services

The desire to extend the existing cellular voice communication networks into a wireless multimedia network have made personal communication systems (PCS) attract a lot of attention. There has been significant growth of interest in integrating multimedia services in a wireless CDMA network. This paper investigates the effect of the variable bit rates of traffic sources on the network capacity. Two access control schemes are considered: the bursty scheme and the smooth scheme. The former specifies the same spreading ratio for all users, which makes a low-rate source have a shorter duty cycle of transmission. The smooth scheme requires low-rate sources to use a higher spreading ratio to keep their duty cycles full. An analytical model is developed to compare the performance of both schemes and the results shows a trade-off. Though the bursty scheme can easily accommodate services of different bit rates, its burstiness is found to have a negative effect on the system capacity. Whereas the smooth scheme improves the system capacity at the cost of extra complexity in managing different spreading ratios. The numerical results for the capacity of an integrated voice/video CDMA networks are presented. It is found that the smooth scheme improves the capacity over the bursty scheme by 6% to 15% with a positive association with the percentage of low-rate sources in the traffic mix