Research On The Key Technology Of Uplink In LTE Physical Layer

3GPP Long Term Evolution (LTE) has many advantages, such as lower transmission delay, higher transmission rate, optimized network structure and reduced operating costs. As an influential standard, LTE gained rapid development. The2.6GHz LTE equipments use smart antennas. It is important to research on the channel model and more efficient anti-fading technology. LTE background, characeter, protocol architecture and the basic principles of LTE physical layer were described. Spatial Channel Model Extension (SCME) and International Mobile Telecommunications Advanced (IMT-A) channel model have been built. Frequency offset caused by high speed movement and its compensation methods were analyzed. Diversity reception is used to resist fading in the LTE uplink. Simplified algorithm was proposed to reduce computational complexity and improve processing efficiency. The major work includes:(1) Study on the reference signal, channel coding, rate matching, cyclic prefix and signal-carrier technology (SC-FDMA).The PAPR character of SC-FDMA was analyzed.(2) SCME and IMT-A channel model were established. Frequency offset caused by Doppler shift and its compensation methods were analyzed, the results show that compensating frequency offset can better support high-speed movement in LTE system.(3) Simplified interference rejection combining (SIRC) algorithm was proposed. Selection combining (SC), equal gain combining (EGC), maximum ratio combining (MRC), interference rejection combining (IRC), simplified maximum ratio combining (SMRC) and SIRC were analyzed with simulation. According to the results, the effect of SC and EGC is pooper and shouldn’t be used. Using SIRC in eight antennas system, computational complexity can be reduced to1/8N with1dB SNR loss. To improve processing efficiency, SMRC rather than MRC can be used when there is weak or no interference and SIRC rather than IRC can be used when there is correlated interference.(4) Build simulation platform of the uplink, study on the methods of demodulation, Turbo decoding and channel estimation. Diversity reception algorithms were verified by frame error rate, throughput and constellation. The method of reducing computation and antennas subarray division when using SIRC and SMRC to realize were proposed.