Study On The Method Of Base Station Cooperation Limited Information Interaction

The realistic method of the wireless spectrum allocation as well as the poorwireless transmission environment, bring a huge challenge to satisfy the requirements ofhighspeed wireless communication systems. However, a rising wireless communicationtechnology which employs collaborative communication mechanism, namely"cooperative communication", provides a new way to exploit the space resources. Asone of the key technologies to improve spectrum efficiency in the future wirelesscommunication, in recent years, either in the research field or in engineering,cooperative communication attracts widespread attention.Concurrent presence of inter-cell and intra-cell interferences becomes the majorimpediment to reliable downlink transmission in multi-cell multi-user networks.Harnessing such interferences largely hinges on two levels of information exchange inthe network: one from the users to the base-stations (feedback) and the other among thebase-stations (cooperation). Once full CSI feedback and full cooperation is viable, allthe users report their CSI to all base-stations, and all base-stations share theirinformation streams. However this requirement, especially in large networks, canpotentially overburden the feedback channels as well as the backhaul channels thatconnect the base-stations. Therefore, this thesis demonstrates that full informationexchange is not a necessary condition for achieving the optimal capacity. Then thisthesis shows how it influences the performance of CoMP system when informationexchange is limited. At last, this thesis proposes a few uplink macro-diversityalgorithms in LTE system.The structure of the thesis is as follows:The first chapter briefly introduces the cooperative communication technology, andits application in3G LTE-Advanced. Then this chapter briefly introduces the notion ofCooperative MIMO and the current development of backhaul technologies.The second chapter performs a theoretical research on limited informationexchange of cooperative MIMO network, describes the scheduling framework and feedback mechanism to produce the optimal capacity scaling scheduling, and evaluatesthe level of information exchange needed by the scheduling framework. The formulasand theories are deduced and finally simulation results are shown for proving andanalyzing.Chapter III introduces two Joint-processing precoding algorithms in CoMP system,and proposes a method that quantizes the CSI for the two algorithms above. Then theimpact on the system performance at different quantitative degrees is discussed andsimulation results are shown.Chapter IV focuses on uplink macro diversity technologies in LTE system. Basedon SC and GC, three algorithms are proposed. Then we show different BERs andBLERs caused by different algorithms, and backhaul expenditures are also put intoconsideration. At last simulation results are given out.Chapter V compares and analyzes the theory and simulation results produced bychapters above, and then summarizes the whole article.