Performance enhancement and compensation of carrier frequency offset using CRA‐AA for uplink in SDMA system

Abstract

SUMMARYRecently, the Space Division Multiple Access (SDMA) scheme has been proposed to improve channel utilization efficiency. SDMA requires separation and detection schemes in the base station because serious interference develops among all of the users accommodated by the same channel. In this paper, we propose the Channel Response Assisted Adaptive Array (CRA-AA) that estimates the channel response in the uplink and uses this result to indirectly control the directivity, and compare its performance to those of MMSE adaptive array and joint detection. We also study a scheme to compensate for the carrier frequency offsets generated at each user. We found that CRA-AA had superior performance in the presence of both fast fading and carrier frequency offsets.

Statistical characteristics of MIMO-OFDM transmission systems in a multipath environment where the delay spreading exceeds the guard interval

“…Various methods for channel response estimation have been proposed. In this study, estimation based on the least-square error [9] is used, since it uses a simple calculation and can be applied to OFDM. The method of channel response estimation is described below.…”