Comb-type pilot OFDM system receiver

Abstract

The invention discloses a comb-type pilot OFDM (Orthogonal Frequency Division Multiplexing) system receiver, comprising a setting module used for presetting an iteration cycle index threshold and a cycle index counting initial value; a synchronous module which employs a short preamble to realize coarse synchronization, and a long preamble to realize fine synchronization and frequency offset estimation; an estimation module which employs extracted pilot frequency in each data symbol to estimate the coefficient of a base expansion model, and then calculates the channel estimation value of a time domain corresponding data symbol; an equalization module utilizing a received frequency domain data symbol and a channel estimation result to perform frequency domain equalization; a demodulating, de-interleaving and channel decoding channel used for demodulating, de-interleaving and decoding equalized data; and a determination module used for determining whether an iteration cycle index reaches a preset iteration cycle index threshold; if not reaching the preset iteration cycle index threshold, performing a new cycle of channel estimation by utilizing decoded data, and if reaching the preset iteration cycle index threshold, further determining whether an iteration circulating forward-backward algorithm converges; if an iteration circulating forward-backward algorithm converges, completing a data receiving process, and otherwise, adjusting a synchronous position and performing channel estimation again. The Comb-type pilot OFDM system receiver is suitable for a high speed wireless communication system.

Description

technical field [0001] The invention relates to the field of communication technology, in particular to a comb pilot OFDM system receiver under high-speed mobile wireless channels. Background technique [0002] One of the core technologies of the intelligent transportation system is the short-range communication system applicable to the transportation field. In various transportation-specific short-range communication systems, the IEEE802.11p standard is valued for its superior performance. [0003] The frame structure of the IEEE802.11p protocol, the long and short preambles are the same as those of the IEEE802.11a. figure 1 Schematic diagram of the frame structure adopted for IEEE802.11p (the frame structure of IEEE802.11p is the same as that of IEEE802.11a, that is, the data symbol time is twice that stipulated in the IEEE802.11a protocol), in which the first 10 symbols (symbol) are short preambles, used It is used for coarse synchronization, while the latter two symbols...

AI Technical Summary

Problems solved by technology

However, in a high-speed mobile environment, the communication quality of the OFDM system is greatly reduced due to Doppler frequency shift and channel fast time-selective fading. The above receiver structure is not suitable for high-speed mobile dual-selection channels.

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