Resource allocation for OFDMA-based cognitive radio systems with minimum rate constraints

In this paper, we study the resource allocation problem for real-time services in OFDMA-based cognitive radio (CR) systems. A novel resource allocation algorithm is proposed to maximize the sum-rate of all CR users while keeping the interference introduced to the primary user (PU) under a specified threshold and at the same time to meet the constant transmission rate for each CR user to guarantee the real-time service. In contrast to classical resource allocation algorithms, the proposed algorithm can achieve higher transmission rate and guarantee each CR user´s target transmission rate.