Reseach On Optimization Desigin Of Nonlinear Precoding Algorithm

In recent years, with the development of mobile communication systems, more and more requirements of channel capacity and transfer rate of mobile communication systems are increasing. At this stage, multiple input multiple output(MIMO) technology as the research fouce is widely studied. MIMO is an important core technology of mobile communications system which can greatly enhance the channel capacity. At the same time, the mutual interference between the antennas become a serious problem. Pre-coding technology can solve the problem of inter-antenna interference and remain the low complexity at the receiving terminal, which has important implications for the development of mobile communication system.There are linear precoding and nonlinear precoding two different technologies due to the different from of the transmission data processing. The former use of channel detection technology at the transmission side to obtain channel information, then precancel the antenna interference of the channel linearly. The complexity of linear precoding is low and which lead to easier implementation. However, at the receiver terminal SNR will be reduced by linear precoding, which directly affect the quality of mobile communications. The latter use nonlinear processing, thus ensure the SNR at the receiving terminal but also eliminate the inter-channel interference at the transmitter, which can be sure that nonlinear precoding technology can provide greater performance gains of communication system. However, there is a problem about the nonlinear precoding technique of high complexity. The main content of this paper is to reduce the complexity of the nonlinear precoding with the basis of ensuring communication quality.The Core of non-linear precoding optimization design is how to make a balance between complexity and system performance, reduce the complexity of non-linear precoding on the basis of ensuring the performance, and achieve optimum energy efficiency. Firstly, this paper give a brief introduction of precoding, which about the advantages and disadvantages of the precoding complexity and system performance. Based on these advantages and disadvantages, this paper focused on one kind of complexity and performance trade-off precoding scheme, namely selective vector precoding. Selective vector precoding can reduce the complexity of the system and ensure system performance, while the focus is the user grouping algorithm. In this paper, some different user groups selective VP precoding system has been thoroughly studied about the energy efficiency and complexity. Through analysis and comparison of several of non-linear precoding scheme, the user grouping algorithm of them are too complex by computing vector perturbations too many times. This paper presents a non-linear precoding scheme which can effectively reduce the complexity of user grouping algorithm: selective vector precoding based on the lower bound power estimate. This scheme can calculate the user grouping schemes by using a lower bound power estimate to reduce the complexity. At the same time this scheme send the user grouping scheme to the receiver to reduce the modulo loss, improve system performance. Through a complex analysis and energy performance simulation, proposed non-linear precoding algorithm obtain a well tradeoff of the complexity and performance of the system.