Research On New Technique Of MIMO Transmittion Systems Based On Spatial Modulation

Multiple-input multiple-output(MIMO) is a transmission technique in which there are multiple antennas in both of the transmitter and receiver. This technique has become a key technology in mobile communication system for its high data transfer rate and spectral efficiency.Spatial modulation(SM) is a new techinique of MIMO transmission system raised in recent years, which makes uses of space dimension and activates only one antenna to transmit data symbol at each time slot. Thus, inter channel interference(ICI) and inter-antenna synchronization(IAS) are effectively avoided. Meanwhile, transmitting a part of information data through the selection of the activated transmit antenna ensures a certain spectral efficiency. In addition, the detection complexity of the receiver is reduced as well. Therefore, SM technique is very suitable for an unbalanced MIMO system in which the number of receive antennas is smaller than that of transmit antennas. So far, SM has attracted widespread attention and become an important research direction of MIMO system.Starting from the transmitter and receiver, this thesis investigates the mapping rules and the soft-input soft-output(SISO) iterative detection algorithms of SM system, respectively. In addition, generalized spatial modulation is researched to meet the development of further wireless communication systems.The main work of the thesis is depicted as follows.In Chapter 1, the background of MIMO transmittion technology and the development of SM technique are summarized.Chapter 2 analyses and depicts the mapping rules applicable to different modulation mode such as quadrature amplitude modulation(QAM), multiple phase shift keying(MPSK) and multiple amplitude shift keying(MASK) in SM system.Chapter 3 first describes the basic principle of turbo equalization system. Then, SM technique is combined with turbo equalization to obtain a better performance through soft-input soft-output(SISO) iterative detection. In particular, several typical iterative detection algorithms are presented for coded SM system. Last but not least, an iterative detection algorithm is proposed based on equivalent Euclidean distrance, which costs only a little penalty of detection performance but reduces significant computational complexity compared to ML. The practical value of the proposed algorithm is very considerable.Chapter 4 introduces the technique of generalized spatial modulation(GSM) and describes maximum likelihood(ML) and sphere decoding(SD) detection algorithms for the receiver of GSM. Then, a detection algorithm based on block linear equalization is proposed, which obtains near-optimal performance with at least 50% reduction in complexity compared to ML detection. The algorithm is improved to reduce the detection complexity futher. Thus, an efficient detection algorithm, termed ordered block linear equalization, is presented to achieve a near-ML performance with much lower complexity, which has turned out through simulaiton results. The improved algorithm is more practical for GSM system.Conclusions of the work in the thesis are given in Chapter 5, and the research direction about the development of SM technique in the future communication systems is discussed as well.