A half-blind channel estimating method of orthogonal frequency division multiplexing system

Abstract

A semi-blind channel estimation method of an OFDM system, comprising the following steps: (a) the receiving end of an OFDM system obtains the time / sub-frames of all pilot symbols in two adjacent subframes one by one The channel estimation of the carrier; (b) use the channel estimation of the time / subcarrier of the pilot symbol obtained in step (a) to obtain the initial estimated value of the channel at other time-frequency points; (c) use the digital signal to obtain the finite element set The characteristics of the channel estimation value calculated at this time are optimized; (d) use the two-order model simulation method to further correct the channel estimation optimization value obtained in step (c); (e) according to the set evaluation conditions The obtained channel estimation correction value is evaluated, and if the evaluation condition is satisfied, the channel estimation result is returned, and the end is completed, otherwise, return to step (c). The semi-blind channel estimation method of the present invention can improve the performance of channel estimation without increasing the density of pilot symbols.

Description

technical field [0001] The invention relates to the channel estimation technology of an Orthogonal Frequency Division Multiplexing (OFDM) system, and proposes a new semi-blind channel estimation method, which is suitable for OFDM system transmission. Background technique [0002] In recent years, with the development of the next-generation wireless communication system, the OFDM system has shown its strong advantages and has been adopted by various standards, from European DAB (digital broadcasting), DVB (digital television) standards, and American high-speed DSL modulation standards , to WLAN, WIMAX and LTE, the OFDM system has become a symbol of the new generation of wireless communication technology. [0003] The main technical advantages of the OFDM system are high spectrum efficiency, strong bandwidth expansion, strong anti-multipath fading ability, convenient allocation of spectrum resources, and easy implementation of MIMO technology. [0004] Based on the above adva...

AI Technical Summary

Problems solved by technology

However, the disadvantage of the TDM method compared with the other two distribution methods is that in a high-speed environment, the channel changes quickly. Since the distribution density of the TDM method in the time domain is lower than the other two methods, it cannot track the channel change in time. Only using channel estimation methods such as interpolation will greatly reduce the performance of channel estimation, increase the bit error rate, and even cause the entire transmission process to fail

Under such conditions, if the channel estimation performance is improved by increasing the density of pilot symbols, it will inevitably bring additional overhead of pilot signals and control signaling.

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