Synchronizing method of high-speed mobile OFDM (orthogonal frequency division multiplexing) system

Abstract

The invention discloses a synchronizing method of a high-speed mobile OFDM system. The method comprises the following steps: utilizing the first 10 identical short lead codes in a frame structure of a wireless LAN (local area network) protocol to determine the coarse synchronizing location; according to the coarse synchronizing location, extracting 2 identical long lead codes in a receiving signal and combining with a sliding window to perform fine synchronization; converting the transmitted known long lead codes into a time domain; calculating the mutual correlation value of the extracted long lead codes and the transmitted known long lead codes; determining the maximum of absolute value of the mutual correlation value and the location index corresponding to the maximum; setting the initial value of the preset sliding window; determining the sliding direction of the preset sliding window according to the location index corresponding to the maximum and the set threshold value index, performing fine synchronization, and determining the initial position of the long lead codes. The synchronizing method is applicable to accurately determining the synchronized position of the received information symbol for the OFDM system under the high-speed mobile vehicle-mounted IEEE 802.11p protocol.

Description

technical field [0001] The invention relates to communication technology, in particular to a synchronization method of a high-speed mobile OFDM system. Background technique [0002] One of the core technologies of the intelligent transportation system is the short-range communication system (also known as dedicated short-range communication, Dedicated Short Range Communications, DSRC) suitable for the transportation field. At present, all countries are paying great attention to the research of traffic-specific short-range communication systems, and constantly put forward new methods, new theories and new products. In recent years, with the development of DSRC technology and theory, how to reasonably solve the vehicle-to-vehicle communication problem has become a new research hotspot. Among various traffic-specific short-range communication systems, the IEEE802.11pTM / D5.0, November 2008 (hereinafter referred to as IEEE802.11p) standard has been valued for its superior perfor...

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Problems solved by technology

Depend on Figure 2A and Figure 2B It can be seen that the curve of the metric function M(d) has a platform, and the existence of the platform makes it easy to misjudgment when determining the synchronization position, that is, there is a large deviation, which interferes with the timing of OFDM symbols, thereby causing bit errors in the OFDM system rate increase

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