An OFDM time shift channel measuring method

Abstract

The invention provides an OFDM time-varying channel measuring method, comprising the following steps: generating complex exponential pilot frequency data having the same central frequency point as that of an OFDM sampling sub-carrier, multiplexing the data with data to be transmitted at a transmitting terminal in comb-like format, sending the pilot frequency data received by a receiving terminal in corresponding pilot frequency positions to a multi-phase filter bank realized by N points FFT, amplitude phase united extracting the data outputted by each corresponding passage to obtain initial channel frequency measuring data on a corresponding pilot frequency sub-carrier, obtaining initial channel frequency measuring data on all pilot frequency sub-carriers by linear interpolating, performing IFFT, and acquiring and tracking L-point important taps in time frequency. Finally, the L-point important taps coefficients are zero padded and FFT processed, interpolation in frequency domain is carried out to obtain channel parameters in all sub-carriers positions. By filtering noise by multi-phase filter, the measuring accuracy of parameters of an OFDM time-varying channel in low Signal-to-Noise condition is improved, and the invention has the characteristic of low bit error floor.

Description

technical field [0001] The invention relates to a signal processing method in wireless communication, in particular to an OFDM (orthogonal frequency division multiplexing system) time-varying channel measurement method. Background technique [0002] With the continuous evolution of the third generation, the next three generations and future mobile communication systems, wireless communication systems will provide higher and higher data rates and more reliable communication QoS guarantees. At the same time, the environment where the user terminal is located will become more and more complex with the advancement of modern technology. High-speed movement and various multipath reflection conditions determine that the wireless communication system must be able to adapt to these harsh transmission environments. Orthogonal frequency division multiplexing system can turn wideband multipath frequency selective channel into a set of convoluted parallel narrowband frequency flat fading...

AI Technical Summary

Problems solved by technology

However, to use effective coherent demodulation technology to obtain higher SNR gain, it is necessary to estimate and track channel parameters at the receiving end, especially to achieve high-precision channel parameters under time-varying and low SNR conditions. The low signal-to-noise ratio condition determines that the accuracy of the channel parameter meter is difficult to meet the actual use requirements. At the same time, the complex measurement algorithm needs to use the statistical characteristics of the channel, but the actual environment determines that it is impossible to obtain accurate channel parameters in use. Statistical properties

Images