Mimo Fading Channel Asynchronous Launch Capacity Analysis

As the next generation mobile communication system, the Long Term EvolutionAdvanced (LTE-A) supports downlink rate of up to1Gbps. Considering electromagneticradiation and some other factors, the transmit power of the base station cannot befurther increased, which gradually makes the coverage oblate station smaller. As theinter-cell frequency reuse factor (FRF) of LTE-An is1, the interference of LTE systemhas become an urgent problem.On the other hand, as the user transfer rate increases, the contradiction between thelimited spectrum resources and the high bandwidth requirements has become moreintense. Thus, the spectral efficiency of the communication system needs to beimproved.To solve these two problems simultaneously, a cooperative multi-point transmissiontechnology based on asynchronous transmission is proposed. The collaborativemulti-point transmission technology offers an effective solution to the problem ofinterference between the cells, whereas the asynchronous transmission improves thespectral efficiency. In this paper, the channel capacities of the asynchronoustransmission based MIMO and the asynchronous transmission based MIMO-OFDM areanalyzed in theory as well as the asynchronous transmission based CoMP channel, andresults are validated through computer simulations.Firstly, the channel capacities of the single-user asynchronous transmission basedMIMO system and MIMO-OFDM system are analyzed. A single-user asynchronoustransmission based MIMO transmission model is built by deducing the matrix formulaof the received signal. The channel capacity of the single-user asynchronoustransmission system is analyzed by this model, and the results are validated throughcomputer simulations. Analysis and simulation results reveal that, under the samecondition of SNR, the channel capacity of the asynchronous transmission based MIMOsystem is superior to the synchronous emission based MIMO system. And theperformance grows with the transmit signal frame length.Secondly, an asynchronous transmission based CoMP transmission technology isproposed. An asynchronous transmission based CoMP transmission model isconstructed by introducing an artificial frequency extension based on the traditionalCoMP system. This model can take full advantage of both the spatial diversity and thedelay diversity. Thus, under the same condition of SNR, the asynchronous transmissionbased CoMP system outperforms the traditional CoMP system.Finally, the channel capacity of the asynchronous transmission based Comp isanalyzed and validated through computer simulations. Analysis and simulation resultsreveal that the system capacity of the traditional synchronous transmission based CoMPis inversely proportional to the correlation coefficient of the transmit antennas. Whereas,due to the introduction of the delay diversity, the asynchronous transmission based CoMP takes full advantage of the correlation between the transmitted signals, thusimproves the channel capacity significantly.In this paper, a cooperative multi-point transmission technology based onasynchronous transmission is proposed to solve the problem of co-channel interferencebetween the cells and hence improves the system performance for marginal users andimproves the spectral efficiency of the system. The results of this paper can be appliedto the evolution candidates of the IMT-A, the IEEE802.11, the IEEE802.16and someother wireless communication standards.