Signal detection with time delay estimation for quasi-synchronous MIMO systems on multipath channels

In this paper, signal detection with time delay estimation for quasi-synchronous MIMO systems on multipath channels is considered. The paper first formulates the problem by shifting each user´s signals so that previous results on synchronized system for ISI cancellation based on second-order statistics of the received signals can be applied. The first step effectively reduces the quasi-synchronous system on the multipath channels to the quasi-synchronous system on single-path channels. In the second step, an equivalent model is constructed with the delay information embedded in the reduced channel model. A simultaneous time delay estimation and multiuser detection algorithm is then proposed. The proposed technique can easily be implemented in practical situations as perfect synchronization and knowledge of the channel length and the time delays are not required. Simulation results show that the proposed technique can achieve good performance and is not sensitive to overestimation of the maximum channel length and the maximum time delay