Descending power control method in TD-CDMA system

Abstract

This invention relates to a method for controlling down closed loop power in the TD-SCDMS system including: when a base station tests that the quality of the up link is at a worsen state, it turns itself to a down link resuming period to up-adjust the power control order with the resumed step length response power and down-adjust the power control order with conventional step length response power, in this way, the base station controls power of each down coding combined transmitting channel based on the down closed loop power control mode to strengthen the effect of down closed loop power control when quality of the up and down links drops at the same time.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a downlink 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 downlink closed-loop power control as an example. After receiving the downlink signal from the base station, the user equipment decides whether to increase or decrease the transmit power of the base station according to specific criteria, and generates a corresponding power control command. The power control command generated by the user equipment It is transmitted to the base station through the uplink feedback channel, and the base station adju...

AI Technical Summary

Problems solved by technology

[0004] For the TD-SCDMA closed-loop power control system, 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 declines, The downlink closed-loop power control will be affected. 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

[0005] Similarly, 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 decreases, the uplink closed-loop power control will be affected. If 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

[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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