Comparison and Cost Analysis of Smart and Opportunistic MIMO OFDM Schemes

This paper attempts to compare the system downlink performance of a smart antenna scheme for OFDMA that utilizes channel covariance information with an opportunistic multi-antenna scheme for OFDMA that uses fast limited feedback of the instantaneous channel condition. The schemes are evaluated by means of simulations in a low load scenario and also compared to a simple HSDPA-like scheme. The smart antenna method manages to utilize the multiple antennas better than the opportunistic scheme. Furthermore, the performance of the schemes is inserted into a cost model that assumes that the receivers are relays that use short-range technologies to communicate with user equipments. Also in terms of cost per user equipment, the smart antenna scheme proves to be more suitable for the studied scenario.