Method for expanding time-division synchronous CDMA access system ovelay range

Abstract

In the invention, the method of establishing uplink synchronization by the mobile terminal in the system comprises: a) based on preact of the predetermined sending time, the mobile terminal sends the uplink pilot frequency signals; b) if the mobile terminal is not able to access, the physical layer of the mobile terminal resets the preact of the sending time, and returning to step a. The invention has the following advantages: 1)realizing the wide coverage at all kinds of scenes; 2) no need to scarifying the TS1 time slot as the extra protection time slot; 3) no need to modify the currently-used base station, and only need to make slight modification for the mobile terminal 4) no need to amend the criteria and rule.

Description

technical field [0001] The invention relates to a method for expanding the coverage of a Time Division Synchronous Code Division Multiple Access (Time Division Synchronous CDMA: TD-SCDMA) system, which belongs to the technical field of communication. Background technique [0002] The TD-SCDMA system is a new mobile communication system using Time Division Duplex (TDD) technology. In this system, the uplink and downlink signals are distinguished by time, and there are dedicated uplink and downlink pilot time slots. Uplink and downlink pilot signals to complete the uplink and downlink pilot functions. In the TD-SCDMA system, a wireless frame is 10ms long and divided into two 5ms wireless subframes with the same structure. The structure of the wireless subframe is shown in Figure 1. [0003] It can be seen from Figure 1 that in each subframe (subframe, 1.28Mcps, 5ms, 6400chip), there are 7 regular time slots TS0-TS6 and 3 special time slots, and the 3 special time slots includ...

AI Technical Summary

Problems solved by technology

[0005] (1) The mobile terminal carries out a certain time advance when sending the uplink pilot signal, but in the prior art, the sending time advance of the mobile terminal is based on the mobile The DwPTS received by the terminal and / or the power estimation of the main public control physical channel PCCPCH is determined. For wide-coverage scenarios such as sea and desert, due to differences in propagation models, the mobile terminal cannot accurately estimate the transmission of the uplink pilot signal. time advance;

[0006] (2) Expand the length of the guard time slot, that is, sacrifice the TS1 time slot as an additional guard time slot, but this method requires a relatively large modification of the base station, It is more difficult to realize, and the capacity loss of the system is also relatively large

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