Sum rate analysis of SDMA transmission in single carrier FDMA system

Single carrier (SC) FDMA was agreed to be chosen for 3GPP-long term evolution (LTE) uplink. A recent discussed feature for boosting up bit rates in LTE uplink is to apply SDMA (space division multiple access) to enable users to communicate with the serving base station using the same frequency resource. This paper analyzes the achievable sum rate in SC-FDMA system uplink, where SDMA with frequency domain linear zero forcing equalizer is assumed for the users. Analytical results show that in general SDMA with SC-FDMA has inferior rate performance to that with OFDMA. Furthermore, a simple algorithm is proposed to find the group of users for SDMA transmission based on the wideband average spatial correlation. Significant performance improvement against fixed grouping is shown for 3GPP-LTE uplink scenarios.