Optimal power allocation based on QoS balance for a multi-rate packet CDMA system with multimedia traffic

Usually, when combining two or more services (each having their own QoS requirements), it is difficult to achieve a common operation point for all the services. When we satisfy the highest QoS requirement, the other services will be operating at "unnecessary high quality". In this case, a lot of bandwidth is wasted due to a low traffic load. To solve this problem and to achieve higher spectral efficiency, a "QoS balance" method is developed to optimise the allocation of transmission power and evaluated in a wideband DS-CDMA environment integrated with video and voice services. Our simulation results demonstrate that the capacity of the network or spectral efficiency is improved significantly, by this optimal power allocation scheme.