Distance measuring signal processing method and system for OFDM access system

Abstract

The invention provides a method for processing OFDMA distance signals and a system thereof, which are used to process the distance signals of a wireless communication system which uses the OFDMA technique to obtain a practical ranging code and timing offset in a present ranging time slot. A normal ranging method in an existing technique is a bi-dimensional ergodic process, the complexity of computation is high, and a frequency domain difference ranging method has the problem that the detecting performance of the ranging code and the timing estimating performance are worse due to multi-user disturbance. The processing method of the invention and the system thereof firstly calculate frequency domain difference cross-correlation functions of neighboring carriers in a range channel, then a first screening threshold is calculated, a candidate key set is screened according to the first screening threshold, estimated timing offset is calculated, then, the cross-correlation functions and a second screening threshold between a ranging code frequency domain sequence and a local ranging code are calculated, finally, the practical timing offset is calculated, and the practical ranging code is screened from the candidate key set. The method and the system of the invention can guarantee the ranging accuracy and also can guarantee lower complexity of computation.

Description

technical field [0001] The present invention relates to wireless communication distance measurement technology, in particular to a method and system for processing distance measurement signals of an orthogonal frequency division multiple access system. Background technique [0002] The IEEE 802.16d / e communication system uses the Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) communication scheme, that is, the downlink (the base station transmits data to all users) adopts OFDM technology, and the uplink (the user transmits Data to the base station) adopts OFDMA technology, so different users transmit data to the base station through different sets of subcarriers during uplink. If timing synchronization is not achieved between users, the orthogonality between subcarriers will be lost, resulting in subcarrier Interference between data on a carrier. Therefore, the timing synchronization of each uplink subcarrier is very ...

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Problems solved by technology

[0008] In addition to the problem of poor detection performance, the above two frequency domain difference detection schemes also have problems in the estimation of timing deviation

The above detection scheme uses the phase of the correlation function for timing estimation. This method has the problem of phase inversion, and is also affected by multi-user interference. Therefore, the timing deviation estimation performance of the frequency domain difference detection scheme is poor and cannot meet the requirements of the uplink system. timing synchronization requirements

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