On The Adaptive Mimo Precoding Design For TD-LTE System

By using a series of contemporary wireless communications and signal processing technology, MIMO technology provides us an effective method to overcome the capacity bottleneck for the future wireless communication systems. The core challenge in MIMO technology is the interference elimination of the superimposed signal in wireless media transfer process. Because the precoding techniques can be utilized to effectively improve the capacity of MIMO system, as well as to enhance the reliability performance of the practical application of MIMO technology, MIMO precoding has been incorporated into many broadband wireless communication standards, such as LTE, LTE-A, IEEE802.16e and so on. Therefore the MIMO precoding design will play an important role in the enhanced MIMO system development. In this thesis, we focus on the non-codebook precoding design for the LTE system, as well as the codebook based precoding design for LTE-Advanced system.Since accurate and real-time channel state information is generally difficult to obtain, especially in fast-moving environment. Therefore, with limited feedback, the non-codebook precoding design based on the DCSIT, together with the codebook based precoding design are particularly important in practical applications. Based on the dynamic CSIT model, the thesis discussed the pairwise error probability (PEP)-criterion based non-codebook precoding design and the first order of sum capacity criterion based non-codebook precoding design. And the applicability of the two precoding schemes in LTE system was addressed from the perspectives of the realized precoding performance and the feedback signaling overhead. Our analysis in this thesis unveiled that, the PEP criterion based precoding scheme is capable of ensuring the error rate performance over fast fading with high correlation properties with much less feedback signaling overhead. Thus the PEP criterion based precoding provides a viable MIMO adaptive precoding scheme for the fast time varying channel conditions.Due to the scarce frequency spectrum resource, LTE-Advanced system imposes higher requirements in terms of the realized MIMO throughput and reliability for the codebook based MIMO precoding design. In this thesis, we analyzed and compared the five existing codebook based precoding design with eight transmitting antennas for the LTE Advanced system. Then we proposed an improved adaptive codebook based precoding design scheme by taking into account the reuse of LTE Release8codebook. And the simulation results over the3GPP LTE system validates that the proposed codebook design provides a reasonable precoding scheme for LTE Advanced system with significant performance improvement, tolerable feedback signaling overhead. Moreover, the proposed codebook design is a backward compatible choice for the precoding choice in the existing LTE Release8system, hence it is an attractive and efficient codebook design method.