Orthogonal pilot frequency sequence design method

Abstract

First, the method defines pilot frequency sequence (PFS) composed of column vectors of orthogonal matrix, which is Fourier matrix. Then, the method scrambles PFS, and the scrambling sequence ck satisfies |ck|=1, and scrambled PFS does not influence on requirement of orthogonality. The invention obtains extensive uses in areas of wireless broadband communication and mobile communication, especially in fourth generation mobile communication, multicarrier, and OFDM transmission system. The method is mainly in use for designing sending PFS, and keeping the sending PFS as a signal in normal module in order to raise accuracy for estimating channel of receiver so as to raise performance of receiver.

Description

technical field [0001] The invention relates to a method for designing a pilot sequence, in particular to a method for designing an orthogonal pilot sequence. Background technique [0002] In the wireless communication system based on OFDM transmission technology, the time-frequency selective fading of the channel causes the time and the fading degree of the transmitted signal on different subcarriers to be different. This determines that the pilot symbols of the system are generally distributed in a time-frequency two-dimensional grid space. The density of the grid is determined by the system requirements and the channel quality. The greater the delay spread and Doppler frequency spread of the channel, the more accurate The more pilots are needed for channel estimation, so the estimation method based on pilot symbols is generally widely used in the case of faster channel fading. In the estimation method based on the pilot sequence, the length of the sequence is relatively ...

AI Technical Summary

Problems solved by technology

[0098] When the number of transmit antennas in the MIMO-OFDM system is N T , when the channel memory length is L, from the formula (25), it can be seen that the parameter to be estimated on each receiving antenna is LN T need P ≥ 2 N T - 1 L length pilot sequence , the sequence length increases exponentially with the number of transmitting antennas. When the number of transmitting antennas is large (for example, the base station is configured with more than 4 antennas), the required pilot sequence is very long, which reduces the transmission efficiency of the system.

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