Synchronous information sending method of OFDM system and cell searching method

Abstract

The present invention discloses a sending method of synchronization signals of an orthogonal frequency division multiplexing system and a corresponding cell searching method. The synchronization signal sending method comprises the steps of transmitting system synchronization information to a terminal by a base station, wherein, the synchronization information comprises lead codes which comprise main lead codes and sub lead codes, and also comprises broadcast channels; modulating the main lead codes on a useful sub-carrier of a fixed bandwidth which is the minimum of the bandwidths used by each coexistence system; the base station sending sub lead codes with the types corresponding to the system used in the base station; the base station placing, the main lead codes, which carries information indicating the types of the sub lead codes, in the first orthogonal frequency division multiplexing symbol of the first sub-frame of each frame; placing the broadcast channels in the first orthogonal frequency division multiplexing symbol of the second sub-frame of each frame; placing the sub lead codes in the second orthogonal frequency division multiplexing symbol of each sub-frame. According to the present invention, many systems can be compatible with each other.

Description

technical field [0001] The invention relates to the field of digital communication, in particular to a synchronization information sending method and a cell search method of an orthogonal frequency division multiplexing system. Background technique [0002] As a multi-carrier transmission mode, OFDM (Orthogonal Frequency Division Multiplex) converts a high-speed transmission data stream into a set of low-speed parallel transmission data streams, making the system frequency-selective to multipath fading channels The sensitivity of OFDM is greatly reduced, and the introduction of cyclic prefix further enhances the ability of the system to resist Inter-symbol Interference (ISI). In addition, the high bandwidth utilization rate and simple implementation make OFDM in wireless communication Watershed applications are becoming more and more widespread, for example, WLAN systems, 802.16e systems based on Orthogonal Frequency Division Multiple Access, and 802.16m systems (fourth gene...

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Problems solved by technology

[0005] According to the 802.16e standard: the preamble is sent on the entire bandwidth of the first symbol of the downlink. At the same time, 802.16e systems with different bandwidths (such as 5MHz, 10MHz, and 20MHz) use different preambles. In order to access the system, the terminal needs very The amount of calculation is large, and it is difficult for the terminal to work under systems with different bandwidths, so the existing technology brings problems of complex implementation and long access time

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