Nonlinear power assignment and its impact on the capacity of multimedia CDMA systems

When multimedia traffic is introduced into code division multiple access (CDMA) mobile networks, power should be assigned to users according to different bit rate and quality of service (QoS) requirements, in order to provide each user an acceptable connection. We derive the sufficient and necessary convergence condition for the power assignment algorithm taking into account only average signal-to-interference ratio (SIR) requirements, and study the normalized demand (demand-to-resource ratio) for a given outage probability requirement. Lower and upper bounds of the normalized demand are obtained and two new power assignment algorithms taking into account both average SIR and outage probability requirements are proposed. Numerical results confirm the advantage of the proposed algorithm