Method and device for origination of ranging process in TDD-OFDMA (time division duplex-orthogonal frequency division multiple access) system

Abstract

The invention discloses method and device for the origination of a ranging process in a TDD-OFDMA (time division duplex-orthogonal frequency division multiple access) system, mainly for solving the problem of large influence on the ranging performance of the prior art by a channel frequency selectivity and a near-far effect. The ranging steps comprise: (1) a channel estimation for a downlink frame, (2) a pre-equalization, (3) a code word mapping, (4) an amplitude-limiting processing, (5) an IFFT (inverse fast Fourier transform), and (6) an initial power control. The ranging device comprises a downlink frame channel estimation module, a pre-equalization module, a code word mapping module, an amplitude-limiting module, an IFFT module and an initial power control module. The method and device for the origination of a ranging process in a TDD-OFDMA system disclosed by the invention have the advantage of being capable of eliminating the near-far effect and keeping the orthogonality of a ranging code in a non-fast-transforming frequency selectivity channel; and the method and device are suitable for the origination of a ranging process in a time division multiplexing WiMax (worldwide interoperability for microwave access) or LTE (long term evolution) system.

Description

technical field [0001] The present invention belongs to the field of communication technologies, and further relates to a method and device for transmitting a ranging process in a Time Division Duplex Orthogonal Frequency Division Multiple Access (TDD-OFDMA) system. The present invention can be used in ranging transmitter modules of systems such as Worldwide Interoperability for Microwave Access (WiMax) and Long Term Evolution (Long Term Evolution, LTE) to realize the ranging process from the user to the network. Background technique [0002] Ranging is an important process for users to access the network in the WiMax system and LTE system. Through the ranging process, the user's access signal is detected by the base station, and the correct time offset and transmit power adjustment are obtained, thereby eliminating the near-far effect and establishing Uplink synchronization. In the future, the mobile communication system will use more micro cells and even pico cells. In th...

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Problems solved by technology

[0004] The disadvantage of this method and device is that it does not consider the influence of the frequency selective channel. If the frequency selectivity of the channel is very strong, the correlation of the ranging signal is greatly affected by the channel, and the correlation peak may be submerged in noise and In this case, no matter how the threshold is set, the ranging performance will not be improved

[0006] The disadvantage of this method and system is that since the cross-correlation between codewords cannot be an ideal zero cross-correlation, in severe frequency-selective channels, the user's codewords are severely distorted, and the differential cross-correlation detection method is not It can eliminate the frequency selectivity of the channel, but will introduce more interference in the differential processing, and its effect cannot meet the needs of actual engineering

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