Rate maximization in space-division multiple access (SDMA) /multi-input-single-output (MISO) /OFDM systems under QoS and power constraints

This paper considers the resource allocation problem in space-division multiple access (SDMA)/multi-input-single-output (MISO)/OFDM systems. Our objective function is to maximize the total system data rate subject to total power constraint and each user´s quality-of-service (QoS) requirement. In this SDMA/MISO/OFDM multiuser system, each user possesses a spatial filter in each subcarrier to remove interference from other users in that subcarrier. We observe that the number of users in a subcarrier has two conflicting effects on the system throughput. Adding more users in a subcarrier increases the number of spatial channels; however, at the same time, it introduces more interference among the users which reduces the throughput in each spatial channel. This paper takes into consideration these effects to solve the rate maximization problem.