Power Allocation for Group LDS-OFDM in Underlay Cognitive Radio

Abstract

Low density signature orthogonal frequency division multiplexing (LDS-OFDM) is a promising multiple access that increases spectrum utilization. In LDS-OFDM, each subcarrier can be accessed by more than one user, however, it is limited to d _c users. Each user spreads its symbols in a number of d _v subcarriers. In this paper, we propose power allocation for LDS-OFDM in underlay cognitive radio to increase throughput for each secondary user (SU) by manage the power weighting of each user in every subcarrier. The simulation results confirm that our proposed algorithm can increase the throughput of SU compare to equal power weighting. Grouping on allocation resource will affect the outage probability and SU's throughput.