Research on Pre-coding Technology Analysis of LTE Systems

Abstract

Abstract. As the demand for wireless communications become more sophisticated, the wireless communication system also received an unprecedented flourish. LTE as the evolution of 3G systems, which greatly enhance the spectrum utilization system, it is possible to obtain higher than traditional wireless communication system throughput. In order to fully utilize LTE technology brings the system upgrade pre-coding technology, at the transmitter to send data preprocessing information based on the channel, so as to simplify the complexity of the receiver or the purpose of improving system performance. In order to meet the needs of LTE systems in high-rate and high capacity aspects, LTE system supports multiple input and output technology downstream applications, including spatial multiplexing, beamforming and pre-coding technology. LTE system pre-coding technology will help to assess the performance of LTE systems, and promote its practical application. The pre-coding technology would facilitate a more standardized process, and enhance the right to speak in the international field of standardization. Theoretical Introduction of LTE TechnologyLTE (Long Term Evolution) project is an evolution of 3G, LTE is not widespread misunderstanding of 4G technology, but a transition between 3G and 4G technology, is the world standard of 3.9G, it improves and enhances the 3G air access technology, the use of orthogonal frequency division multiplexing technology as the sole criterion for its wireless network evolution. LTE system improves cell edge user performance, and can improve cell capacity and reducing system latency. In this scenario, the role of the pre-coding technique is more important.Compared with 3G, LTE has the following technical characteristics: improve communication speed downlink peak rate of 100Mbps, the behavior of 50Mbps. Improve spectral efficiency, downlink 5 (bit/s) / Hz, 3-4 times the R6 version; uplink 2.5 (bit/s) / Hz, 2-3 times the R6 version. In the packet domain services as the main target, the overall architecture of the system will be based on packet switching. Reduce wireless network delay: sub-frame length is set to 0.5ms and 0.675ms, and solve the problem of backwards compatibility and reduces network latency [1] . LTE system requirements can be achieved at a bandwidth of up to 20MHz 100Mbit /s downlink peak rate, so LTE wireless access technology with a new technology and MIMO OFDM technology. Because of its openness, it was supported by the vast majority of manufacturers to determine the LTE standard authoritative position in the industry. Some countries and regions have started commercial operation LTE systems attempt. In the actual system, due to the limited feedback channel capacity, using a codebook based pre-coding technology limited feedback. For a limited feedback precoding, the most important issue is the design of the code and the code word selection algorithm. The Basic Theory of Pre-CodingPre-coding technology is known channel state information (Channel States Information, CSI) in the ...