Performance Comparison of Linear Precoders for TDD Large Scale MIMO System with Imperfect Reciprocity and Channel Estimations
Channel estimation is an essential component, in which channel state information playing very important role in wireless communications. But acquiring CSI in practice is a challenging issue for massive MIMO systems. To reduce the over burden for obtaining channel impulse response of huge Multi input multi output system channel reciprocity in TDD domain is suggested, because the forward link channel data can be derived from the reverse link signal without any feedback involvement. Because of mismatches at uplink, downlink channels maintaining reciprocity in TDD systems is impractical. We study the impact of multiplicative reciprocity error for precoders (Zero forcing, MMSE and MRT) performance along with channel estimation error. In this paper effect of RF mismatches impact on linear precoders is analyzed and simulated in terms of SINR versus SNR under additive white Gaussian noise.
Firstly, according to the definitions in the ISO 9646 about the protocol conformance testing, some basic concepts of protocol conformance testing are presented. Secondly, the basic theory, definition, and properties of the labelled transition system (LTS) are given. By using the theory LTS, the test suite, test case and test generation are defined. Thirdly, the implementation relation which plays a important role in test generation is described. Finally, after giving the definition of the input/output system implementation relation, the implementation relation ioco is introduced, in which the input/output system and Δ transformation are used, and a test automation algorithm is given.