A Novel Double Codebook Design And Robustness Analysis In LTE-A

The sustained rapid growth of the mobile users number and the spring up of wireless multimedia operation causes the contradiction between the requirement of transmitting rate increasingly rising and limited available frequency bandwidth increasing conspicuous. In order to improve the reliability and efficiency of wireless communication, researchers seek the wireless resource from time, frequency and so on domains, and gradually obtain widely use in TDMA and CDMA system. Comparing to the mature technologies in the time and frequency domain, recent years, the researchers start to seek the technologies in spatial domain with enthusiasm, and obtain quite rapid development.The introducing of MIMO in spatial domain can obtain good tradeoff between multiplexing and diversity for applying, however, as most of the existing theoretic analysis is based on the transmitter and receiver can obtain full CSI, and the attaining of the CSI in practical system, especially in LTE-A which is based on MIMO/OFDM, is subject to channel feedback quantity. Therefore, we can not attain the real and complete full CSI. In addition, the antennas in MIMO are affected by size and accuracy of erection in practice. The estimation error of CSI is inevitable. Hence, how to use as lower as possible feedback quantity to obtain direct/indirect CSI with as higher as accuracy has become a pressing problem for the development of LTE-A.The thesis takes the project named Cross-layer optimization techniques oriented IMT-Advanced, which is supported by National Key Technology R&D Program in the 11th Five year Plan of China as the background. On the basis of single codeword for LTE 4Tx, according to the intrinsic properties of MIMO in LTE-A 8Tx, a novel codebook structures with double codeword for LTE-A 8Tx is proposed. The codeword structure takes into account the channel property of fast fading caused by multi-path and slow fading caused by distance. By utilizing the structure, we can realize the trimming of beams in a rather wide range on the covering axis of W2 , after costing one bit feedback to fix W1 . In this way, the cost of feedback is reducing obviously. Comparing with the Samsung general codebook proposed, the codebook proposed in the thesis can obtain better SINR performance. On the basis of the above research, according to the influence of antenna size and location accuracy to the coverage of codeword, the thesis analyze the robustness of the double codeword design and existing design. The simulation shows that the proposed double codeword has a better robustness.The proposed double codeword and corresponding robustness analysis, enriching the codebook design resources in LTE-A, moreover, providing a new method to codebook robustness analysis.