Improving the spectral efficiency of multiuser OFDM system with V_BLAST architecture by adaptive resource allocation

This paper investigates the problem of adaptive resource allocation in the downlink of multiuser OFDM systems with V_BLAST architecture. In order to get a high spectral efficiency even in low SNR, we propose a novel low-complexity adaptive subchannel-bit allocation and power reallocation algorithm. The algorithm considers the users´ quality of service (QoS) requirements. Simulation results show that the proposed algorithm performs almost as well as the optimal solution. Moreover, higher spectral efficiency is achieved for larger number of users due to the multiuser diversity and the power reallocation is used in low SNR field.