Timed synchronization method for orthogonal frequency division multiplexing (OFDM) system based on IEEE 802.11ac

Abstract

The invention requests to protect a timed synchronization method for an orthogonal frequency division multiplexing (OFDM) system based on IEEE 802.11ac, and relates to a mobile communication technology, for correctly detecting an initial position under the condition of sending multi-frame data. The method mainly comprises the steps of firstly sampling a received signal, and detecting whether a data size is more than the data size of the minimal frame; then expanding a local sequence in a not very high throughput capacity, and then performing inverse Fourier transform and expansion; and at last associating sampled data with the processed local sequence to form a cost function, so as to correctly detect the initial position of the frame. According to the method provided by the invention, the characteristics of the received signal, an IEEE 802.11ac frame structure and a training sequence of the not very high throughput capacity are combined, so that implementation complexity of a timed synchronization algorithm is reduced, and thus a simple and efficient solution is provided for timed synchronization of the frames.

Description

technical field [0001] The invention belongs to the technical field of mobile communication, in particular to a timing synchronization method of an OFDM system based on IEEE 802.11ac. Background technique [0002] OFDM is a multi-carrier high-speed spread spectrum transmission technology, which is widely used in WLAN (Wireless Local Area Networks, wireless local area network) transmission, such as the IEEE 802.11ac protocol. Although in the OFDM system, the carriers of each sub-channel are orthogonal to each other and the spectrum overlaps with each other, which not only reduces the mutual interference between sub-carriers, but also improves the spectrum utilization rate, but the corresponding synchronization requirements for the receiver will be particularly high, so Timing synchronization is particularly important as the first step in receiver processing. If the timing is not accurate enough, it will lead to a sharp decline in system performance. [0003] For the data tr...

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Problems solved by technology

Although this document can effectively detect the starting position of the frame, this type of algorithm has a huge amount of calculation and high complexity, and there is a weak correlation between the short training sequence and the long training sequence in the non-very high throughput. In the case of low signal-to-noise ratio, this scheme is likely to misjudge the frame start point

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