An uplink power control method for TD-SCDMA system

Abstract

The present invention relates to a technique field of a wireless communication, and in particular relates to an ascending closed-loop power control method in a TD-SCDMA system. The method comprises the following procedures: when the user facility detects that the quality of the descending chain is in deterioration state, switching the user facility to an ascending chain restoring cycle; and in the period of the restoring cycle, responding the power control command of power increasing with a restoring step width by the user facility, and responding the power control command of power reducing with a routine step width. Through the method, the user facility executes power control to each ascending coding combination transmission channel in the system according to an ascending closed-loop power control mode. The effect of the ascending closed-loop power control is reinforced when the simultaneous abrupt reductions of the ascending and descending chains are likely to appear. The chain maintaining capability controlled by the closed-loop power in the TD-SCDMA is increased.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to an uplink power control method in a TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) system. Background technique [0002] The closed-loop power control technology is a key technology in the TD-SCDMA system. The user equipment / base station periodically adjusts the transmission power according to the power control command carried by the feedback link from the base station / user equipment. [0003] Take the uplink closed-loop power control as an example. After receiving the uplink signal from the user equipment, the base station decides whether to increase or decrease the transmit power of the user equipment according to specific criteria, and generates a corresponding power control command. The power control command generated by the base station It is transmitted to the user equipment through the downlink feedback channel, and the user equipment adj...

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Problems solved by technology

[0004] For the TD-SCDMA closed-loop power control system, the necessary condition for the uplink closed-loop power control to work well is that the downlink power control command word feedback channel needs to maintain a certain communication quality. If the communication quality of the downlink power control command word feedback channel declines, The uplink closed-loop power control will be affected. When the communication quality of the downlink power control command word feedback channel deteriorates to a certain extent, the uplink closed-loop power control will fail

[0005] Similarly, the necessary condition for the downlink closed-loop power control to work well is that the uplink power control command word feedback channel needs to maintain a certain communication quality. If the communication quality of the uplink power control command word feedback channel decreases, the downlink closed-loop power control will be affected. Influence, when the communication quality of the uplink power control command word feedback channel deteriorates to a certain extent, the downlink closed-loop power control will fail

[0006] Since the closed-loop power control of TD-SCDMA has the characteristic that the control effect on the transmit power in a certain direction (uplink or downlink) depends on the link quality in the other direction (downlink or uplink), so in the TD-SCDMA system there are When the quality of the uplink and downlink suddenly drops to a certain level at the same time, there is a risk that the power control of the uplink and downlink will fail at the same time. call dropped

[0007]For TDD systems such as TD-SCDMA, the uplink and downlink work in the same frequency band, the correlation between uplink and downlink is relatively large, and there are many factors that cause the link quality to drop suddenly (such as sudden occlusion of ground objects, corner effects, etc.) will work simultaneously in the uplink and downlink, so that the closed-loop control system of TDD systems such as TD-SCDMA will suddenly drop the quality of the uplink and downlink to a certain extent. The risk of failure is greater than that of the FDD system

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