A method and device for terminal frequency point blind search in LTE system

Abstract

The present invention provides a blind search method and device for frequency points of LTE system terminals, belonging to the field of mobile communications. The method adopts a three-step search method, and the fine control of step size gradually reduces the range of search frequency bands, position repeatability and frequency. The point continuity ensures that the actual system frequency is gradually approached, and the local primary synchronization signal is used for correlation detection to find the correct frequency point while also obtaining the real local primary synchronization signal and synchronization position; the invention also discloses a LTE system terminal frequency point blind search device; compared with the prior art, the present invention can effectively resist the influence of noise and multipath, the probability of finding the correct frequency point in the candidate frequency points is increased by more than 30%, and the blind search time of frequency points is shortened by more than 35%, which greatly Improve the performance of frequency point blind search.

Description

technical field [0001] The invention belongs to the field of mobile communication, in particular to a method and device for blindly searching frequency points of terminals in a TDD (time division duplex) LTE system. Background technique [0002] In order to meet people's increasing demand for data services, the 3rd Generation Partnership Project (The 3rdgeneration Partnership Project, 3GPP) launched the 3GPP "Long Term Evolution Project", referred to as the 3GPP LTE (Long Term Evolution) project, which aims to The advanced 3G system provides stronger data service support and provides users with better services. According to the TDD LTE system frame structure defined in the 3GPP standard TS 36.211 (R8), such as figure 1 As shown, the wireless frame length is 10ms, corresponding to 307200Ts. Each radio frame is further divided into two 5ms half-frames, and each half-frame includes five 1ms subframes. If the uplink and downlink switching point period of the system is 5ms, th...

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Problems solved by technology

However, this method has the following problems and deficiencies: 1) It cannot effectively resist the shift of the peak value of the main synchronization related power caused by frequency selective fading. peak, and frequency selective fading will cause the distortion of the spectrum of the main synchronization signal, resulting in the peak value of the main synchronization related power value not at the correct frequency point within the frequency point search range, and an offset occurs within a certain range

And because the interval scanning strategy is adopted, the correct frequency point is located at the end of the candidate frequency point list, or is not in the candidate frequency point list, which increases the time to access the cell and eventually causes the overall performance of the UE to decline; 2) due to the main synchronization signal The occupied bandwidth is only 1.4MHz, taking into account the performance of frequency point blind search and low complexity requirements, using low grid interval scanning with a step size of 200KHz, then under the premise of completing the first step (scanning frequency band is 20MHz), at least 20M / 200K=100 wireless frames, that is, 1s. Considering that in order to resist Gaussian white noise and improve performance, each scanning frequency point may need to accumulate multiple wireless frames, which increases the time for blind search of frequency points and prolongs cell access. time

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