Performance analysis and power allocation for the unsaturated two-user interference channel

The performance analysis is important for quality of service (QoS) guarantee, which has not been well studied in the interference-limited system. The authors study the QoS performance of each user in an interference-limited system when the power control policy is used to maximise the sum rate of users. Since service processes of users are correlated, the authors first propose a two-dimensional Markov chain to model the transition among queue states of users. Through solving the Markov chain, the authors derive the closed-form formulae of the stationary probability of the queue length and other QoS metrics of each user. The analysis results indicate that the power allocation problem should be reconsidered in unsaturated networks since the power allocation policy designed for saturated networks is no longer appropriate. The authors thus develop a new power allocation algorithm which considers queue length and channel quality jointly. Finally, the simulation results verify that the authors' analytical method provides accurate estimations of QoS metrics and the proposed algorithm enhance the power efficiency and improve the queue performance of each user.