| Orthogonal Frequency Division Multiplexing(OFDM)technology is the core technology of the fourth generation wireless mobile cormmunicatior,It has the advantages of effectively suppressing the frequency selective fading,high frequency spectrum utilization,and high-speed data transmission of wireless multipath channels.,Because the path between the t Transmitter and the receiver of the wireless communication system is complex and variedeits propagation performance is limited by the wireless channelobut the randomtess of the wireless channel is large and the analysis is difficult.It is of great significance to explore the large-scale fading caused by the long-distance transmission of signals in the wireless propagation process and the influence of complex environments such as rmulti-path propagationshigh-speed movementOand co-channel interference on OFDM signals.This article simulates OFDM signals in cdifferent environments.The main tasks are as follows:(1)The basic theory and key technology of OFDM technology are studied.The advantages and disadvantages of OFDM technology and the impact of wireless channel on wireless cozmmunication are introducedoSeveral channel models are introduced.(2)The large-scale fading channel model was analyzed.The characteristics of the models and the model errors were compared by simulation.The prediction accuracy of several models was compared in urban,suburrban and rural scenarios,and the OFDM signals in urban,suburban and rural scenarios were simulated separately.And simulated the OFDM signals iin three integrated scenarios of urban,suburban and rural areaso(3)The main parameters of the IEEE802.1ag standard aad the physical layer are introduced The OFDM signal in IEEE802.ffg is constructed using MatlabiThe effects of high-speed motion,multipath propagation,and co-channel interference on the OFDM signal im IEEE802?lig are simulated separatelyI Finally,the LS algorithm is passed.The LMMSE algorithr estimates the wireless channel to improve system performance. |
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