A STDMA throughput enhancement scheme with heuristic scheduling in cognitive radio wireless networks

This paper proposes a spatial time-division multiple access (STDMA) based scheme (STBS) to enhance the system throughput in cognitive radio wireless networks. Especially, the proposed scheme is suitable for the situation when the available number of channels is far less than the number of secondary users (SUs). The system design includes: 1) a novel criterion based on SINR constraint (SC) to determine the feasibility of spatial reuse of spectrum; 2) a heuristic spectrum allocation and scheduling (HSAS) algorithm. Simulation results show that in comparison with the STBS based on Interference range (IR) criterion proposed in [5], the proposed scheme can improve the system throughput as much as 100% when the number of channels is 1/5 of the number of users as well as guarantee a low outage ratio of system blow 2% in various scenarios.