Time-domain synchronous OFDM space-frequency coding time-frequency combination channel estimating method

Abstract

The invention relates to a time-frequency joint channel estimation method of time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) space-frequency coding, which belongs to the technical field of digital information transmission. The steps are: 1) transmit antennas T1 and T2 to perform space-frequency diversity coding; 2) alternately transmit transmission parameter signaling (TPS) information carried on OFDM subcarriers on T1 and T2 according to certain rules; 3) Time-frequency joint channel estimation is performed by using time-domain PN sequence and frequency-domain TPS information; 4) Sending information is recovered through space-frequency decoding. The transmission space-frequency coding time-frequency joint channel estimation method described in the present invention hardly changes the original transmitter system, the processing method is simple, fast and accurate, maintains the transmission efficiency of the system, and supports "soft failure", increasing reliability . At the same time, the present invention does not lose its generality, and can be easily transplanted to other multi-carrier terrestrial digital television broadcasting systems.

Description

technical field [0001] The invention belongs to the field of digital information transmission, and more specifically relates to a time-frequency joint channel estimation method of space-frequency coding (Space-frequency) in a Time Domain Synchronous OFDM (TDS-OFDM) system. Background technique [0002] An important basis for terrestrial digital TV broadcasting or mobile communication is the propagation of radio waves, which propagate from transmitting antennas to receiving antennas in a variety of ways, including free space waves, tropospheric reflection waves, ionospheric waves, and ground waves. Free space waves, also known as direct waves, propagate along a straight line and are used for satellite and external space communications, as well as ground-line-of-sight propagation (for example, between two microwave towers). The troposphere, 10 miles above the Earth, is a heterogeneous medium whose reflective index decreases with altitude. Between 40 and 400 miles in the atmos...

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Problems solved by technology

1998 Tarokh in "Tarokh V, Seshadri N, and Calderbank A. Space-time codes for high data rate wireless communications: performance criterion and code construction. IEEE Trans. on Information Theory, 1998, 44(2): 744-765" The concept of space-time trellis coding (STTC) is introduced, which designs channel coding and antenna diversity as a whole. This method can obtain the maximum gain in theory, but it needs to change the design of the entire transmitting system, the translation of the receiving end The code complexity is also greatly increased

Shortly thereafter, Alamouti proposed a space-time block code (STBC) scheme in his classic paper "Alamouti S.A simple transmit diversity technique for wireless communications. IEEE Trans. on Select Areas in Communications, 1998, 16(8): 1451-1458", Although the coding gain of STTC cannot be obtained, the coding structure and decoding algorithm are very simple, and the diversity gain can also be obtained

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