User/sampling point selection algorithm in multiuser MIMO-OFDM with fractional sampling

This paper presents a user/sampling point selection algorithm for a multiuser MIMO-OFDM system with Fractional Sampling (FS). Through FS, it is possible to separate multipath components and obtain diversity gain in an OFDM system. Therefore, the capacity of the multiuser MIMO-OFDM system increases by 1-2 bit/sec/Hz. This paper also proposes a suboptimum sampling point selection algorithm. It is shown that the suboptimal algorithm shows the capacity close to that of the optimal one. However, when the oversampling ratio increases, the difference on the capacity also grows. Thus, there is a tradeoff between the computational complexity and the capacity improvement.