Method for estimating OFDM rapid-varying channels in low-density pilot-frequency distribution
A technology for pilot frequency distribution and channel estimation, which is applied in multi-frequency code systems, shaping networks in transmitter/receiver, baseband system components, etc. , to achieve high-precision channel parameter estimation and tracking, low bit error rate, and high spectrum utilization.
Inactive Publication Date: 2013-03-06
SHANGHAI UNIV
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However, this method achieves high-precision channel parameter estimation under the conditions of fast change, low signal-to-noise ratio and low-density pilot distribution. The low signal-to-noise ratio and low-density pilot distribution conditions determine that the accuracy of channel parameter estimation is difficult to reach the actual Use requirements, but the actual environment determines that accurate channel statistics cannot be obtained in use
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[0016] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0017] like figure 1 , 2 As shown, the specific steps of an embodiment of the OFDM fast-changing channel estimation method with low-density pilot distribution of the present invention are described as follows:
[0018] A. The source data is channel-coded, modulated, serial-to-parallel conversion, and converted into Valid data to be transmitted in subcarrier format , where B is the frequency domain subcarrier sampling interval of OFDM, Indicates that the result of dividing N by B is rounded down, and the value of B is determined by the maximum delay extension value of the transmission wireless channel;
[0019] B. Generate sub-carrier Gaussian pilot data corresponding to the channel frequency domain sampling position ,in is the carrier frequency, sampling frequency interval, pilot signal amplitude, is the variance, and the le...
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The invention discloses a method for estimating OFDM rapid-varying channels in low-density pilot distribution. The method comprises: multiplexing Gaussian-distribution pilot-frequency data and to-be-transmitted data at a transmitting end according to a time-frequency random insertion mode; performing random down-sampling and multiplexing at a receiving end on a frequency far below Nyquist frequency; transmitting received pilot-frequency data which is obtained through multiplexing and corresponds to a pilot-frequency position to perform compressed sensing channel reconstruction; obtaining S nonzero channel values in a channel delay-Doppler sparse domain; and obtaining the channel parameters of all sub-carriers in a frequency domain through channel coefficient zero padding excepting S nonzero positions, as well as delay-Doppler sparse domain inverse transformation processing. The method has the advantages of performing random down-sampling on the frequency far below Nyquist frequency, utilizing the compressed sensing channel reconstruction to filter noise so as to improve the parameter estimation precision of OFDM rapid-varying channels under pilot-frequency distribution conditions low in signal-to-noise ratio and density and realizing high-precision channel parameter estimation and tracking, along with low estimation-calculation complexity and low bit error rate.
Description
technical field [0001] The invention relates to a signal processing method in wireless communication, in particular to an OFDM (orthogonal frequency division multiplexing) fast-changing channel estimation method with low-density pilot frequency distribution. 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 pa...
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IPC IPC(8): H04L25/02H04L25/03H04L27/26
Inventor 周小平方勇
Owner SHANGHAI UNIV