CN101132207A - Descending power control method in TD-CDMA system - Google Patents
Descending power control method in TD-CDMA system Download PDFInfo
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- CN101132207A CN101132207A CNA2007101277011A CN200710127701A CN101132207A CN 101132207 A CN101132207 A CN 101132207A CN A2007101277011 A CNA2007101277011 A CN A2007101277011A CN 200710127701 A CN200710127701 A CN 200710127701A CN 101132207 A CN101132207 A CN 101132207A
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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
The invention relates to the technical field of wireless communication, in particular to a downlink power control method in a TD-SCDMA (Time Division-synchronization Code Division Multiple Access) system.
Background
The closed loop power control technology is a key technology in the TD-SCDMA system, and the ue/bs periodically adjusts the transmission power according to the power control command carried by the feedback link from the bs/ue.
Taking downlink closed-loop power control as an example, after receiving a downlink signal from a base station, a user equipment determines whether the transmission power of the base station needs to be increased or decreased according to a specific criterion, and generates a corresponding power control command, the user equipment transmits the generated power control command to the base station through an uplink feedback channel, and the base station adjusts the downlink transmission power after receiving the power control command.
For a closed-loop power control system of TD-SCDMA, a necessary condition for good work of downlink closed-loop power control is that an uplink power control command word feedback channel needs to keep certain communication quality, if the communication quality of the uplink power control command word feedback channel is reduced, downlink closed-loop power control is affected, and when the communication quality of the uplink power control command word feedback channel is deteriorated to a certain degree, downlink closed-loop power control fails.
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 degrades, the uplink closed loop power control will be affected, and when the communication quality of the downlink power control command word feedback channel degrades to a certain degree, the uplink closed loop power control will fail.
Because the closed-loop power control of the TD-SCDMA has the characteristic that the control effect of the transmission power in a certain direction (uplink or downlink) depends on the link quality in another direction (downlink or uplink), the risk that the power control of the uplink and the downlink simultaneously fails when the quality of the uplink and the downlink simultaneously suddenly decreases to a certain degree exists in the TD-SCDMA system, and the phenomenon can cause the signal receiving quality of the user equipment to deteriorate for a long time and cannot be recovered through the power control when the phenomenon is serious, thereby causing the call drop of the user equipment.
For TDD systems such as TD-SCDMA, where uplink and downlink work in the same frequency band, the correlation between uplink and downlink is large, and many factors (such as sudden ground feature shielding and corner effect) causing sudden quality degradation of link will act on uplink and downlink at the same time, so that the risk of simultaneous failure of power control of uplink and downlink when the quality of uplink and downlink suddenly degrades to a certain degree occurs in a closed-loop control system of TDD systems such as TD-SCDMA is higher than that of FDD system.
Therefore, a solution for controlling the downlink closed-loop power in the TD-SCDMA system is needed, which enhances the effect of controlling the downlink closed-loop power when the quality of the uplink and downlink links may be suddenly reduced at the same time, and improves the reliability of controlling the closed-loop power in the TD-SCDMA system.
Disclosure of Invention
The main objective of the present invention is to provide a downlink closed-loop power control method in a TD-SCDMA system, which is used for performing power control on each downlink coded composite transport channel (CCTrCH), so as to improve the reliability of closed-loop power control in the TD-SCDMA system.
In order to achieve the above object, the present invention is realized by:
a downlink power control method in TD-SCDMA system is a closed loop downlink power control method, characterized in that it comprises the following steps:
step A, a base station performs a closed-loop downlink power control process according to a conventional power control Step length (Normal _ Step), and simultaneously detects the signal-to-noise ratio of an uplink power control feedback coding combined transmission channel (CCTrCH) which carries a power control command;
step B, the base station detects whether the quality of the uplink is in a deterioration state, if so, the base station is switched to a downlink Recovery Period (Link _ Recovery _ periodic), and during the Recovery Period, the base station responds to a power control command of power up-regulation by a Recovery Step length (Recovery _ Step) and responds to a power control command of power down-regulation by a conventional Step length; if not, the base station performs the closed-loop downlink power control process according to the conventional power control Step length (Normal _ Step).
The step B further comprises the following steps:
step B1, the base station judges the quality of the signal-to-noise ratio of the detected uplink coding combined transmission channel, if the quality of an uplink is considered to be in a deterioration state, the step B2 is carried out, otherwise, the step B3 is carried out;
step B2, the base station is shifted into a downlink Recovery Period (Link _ Recovery _ periodic), during the Recovery Period, the base station responds to the power control command of power up-regulation by a Recovery Step length (Recovery _ Step), responds to the power control command of power down-regulation by a conventional Step length, and the Step B4 is carried out;
step B3, the base station performs a closed-loop downlink power control process according to a conventional power control Step length (Normal _ Step), and the process is performed to the Step A;
step B4, the base station judges whether the downlink Recovery Period (Link _ Recovery _ Period) is finished, if so, the step A is carried out, otherwise, the step B5 is carried out;
and step B5, the base station judges the quality of the detected signal-to-noise ratio of the uplink coding combined transmission channel, if the quality of the uplink is considered to be recovered, the step A is carried out, otherwise, the step B2 is carried out.
In step B1, the base station determines whether the downlink quality is in a degraded state according to the following method:
step B11, performing data smoothing operation on the detected instantaneous signal-to-noise ratio S (n) of the uplink coding combined transmission channel of the nth subframe, wherein p is a forgetting factor:
step B12, mixing
Compared with the threshold T1, if
If the time length of the subframe D1 is continuously smaller than the threshold T1, the step B13 is carried out, otherwise, the step B11 is carried out;
step B13, regarding the uplink quality as being in a deteriorated state, and proceeding to step B11;
the thresholds D1 and T1 in the above steps are obtained through simulation according to the wireless environment.
In step B4, the base station determines whether the uplink quality has recovered according to the following method:
step B41, performing data smoothing operation on the detected instantaneous signal-to-noise ratio S (n) of the uplink coding combined transmission channel of the nth subframe, wherein p is a forgetting factor:
step B42, mixing
Compared with the threshold T2, ifIf the time length of the D2 subframe is continuously greater than the threshold T2, performing step B43, otherwise performing step B41;
step B43, regarding the uplink quality recovery, and proceeding to step B41;
the thresholds D2 and T2 in the above steps are obtained through simulation according to the wireless environment.
In Step B2, the Recovery Step length (Recovery _ Step) after the base station enters the Recovery period is greater than the normal Step length.
The Recovery Step size (Recovery _ Step) may take twice the value of the conventional Step size.
In the step B2, the downlink Recovery Period (Link _ Recovery _ Period) is obtained through simulation and test according to the wireless environment, and the value range is 20ms to 200ms.
By the steps of the method, the technical effects obtained by the invention are as follows:
by the method, the base station controls the power of each downlink coding combined transmission channel (CCTrCH) in the system according to the downlink closed-loop power control mode, enhances the effect of downlink closed-loop power control when the quality of uplink and downlink links is suddenly reduced at the same time, and improves the link maintenance performance of closed-loop power control in the TD-SCDMA system. The problem that the user equipment drops the call due to the fact that the signal receiving quality is deteriorated for a long time and cannot be recovered through power control is avoided.
Drawings
Fig. 1 is a flow chart of a downlink closed loop power control method of the present invention;
fig. 2 is a flow chart of a method of determining uplink degradation in the method of the present invention;
fig. 3 is a flow chart of a method for determining uplink recovery in the method of the present invention.
Detailed Description
Referring to fig. 1, the closed loop downlink power control method of the present invention includes the following steps:
step S102, the base station performs a closed-loop downlink power control process according to a conventional power control Step size (Normal _ Step), and simultaneously detects the signal-to-noise ratio of an uplink power control feedback coding combined transmission channel (CCTrCH), wherein the uplink feedback coding transmission channel carries a power control command;
step S104, the base station judges the quality of the detected signal-to-noise ratio of the uplink coding transmission channel, if the quality of the uplink is considered to be in a deterioration state, the step S106 is carried out, otherwise, the step S108 is carried out;
step S106, the base station shifts to a downlink Recovery Period (Link _ Recovery _ periodic), during the Recovery Period, the base station responds to the power control command of power up-regulation by a Recovery Step size (Recovery _ Step), and responds to the power control command of power down-regulation by a conventional Step size (Normal _ Step), and the Step S110 is carried out;
step S108, the base station performs a closed-loop downlink power control process according to a conventional power control Step size (Normal _ Step), and the Step S102 is performed;
step S110, the base station determines whether the downlink Recovery Period (Link _ Recovery _ Period) is finished, if so, proceeds to step S102, otherwise, proceeds to step S112;
step S112, the base station performs quality judgment on the signal-to-noise ratio of the detected uplink coded composite transport channel (CCTrCH), if the uplink quality is considered to be recovered, the step S102 is performed, otherwise, the step S106 is performed.
Referring to fig. 2 in conjunction with fig. 1, in step S104, the base station determines whether the uplink quality is in a degraded state according to the following method:
step S202, the instantaneous signal-to-noise ratio S (n) of the detected uplink coded composite transport channel (CCTrCH) of the nth subframe is subjected to data smoothing operation as follows, wherein p is a forgetting factor:
step S204, willCompared with the threshold T1, if
If the duration of the subframe D1 is less than the threshold T1, go to step S206, otherwise go to step S202;
step S206, regarding the uplink quality as being in a deteriorated state, and proceeding to step S202;
the thresholds D1 and T1 in step S104 are obtained through simulation according to the wireless environment.
Referring to fig. 3 in conjunction with fig. 1, in step S110, the base station determines whether the uplink quality has recovered according to the following method:
step S302, the instantaneous signal-to-noise ratio S (n) of the detected uplink coded composite transport channel (CCTrCH) of the nth subframe is subjected to data smoothing operation as follows, wherein p is a forgetting factor:
step S304, will
Compared with the threshold T2, ifIf the time length of the D2 subframe is continuously greater than the threshold T2, go to step S306, otherwise go to step S302;
step S306, regarding the uplink quality recovery, and proceeding to step S302;
the thresholds D2 and T2 in step S110 are obtained through simulation according to the wireless environment.
In addition, in Step S106, the Recovery Step size (Recovery _ Step) after the bs enters the Recovery period should be greater than the Normal Step size (Normal _ Step). The Recovery Step size may be set to Recovery _ Step =2 × Normal _ Step in engineering.
In the step S106, the downlink Recovery Period (Link _ Recovery _ Period) is obtained through simulation and test according to the wireless environment, and a typical value range is 20ms to 200ms.
By the method, the base station controls the power of each downlink coding combined transmission channel (CCTrCH) in the system according to the downlink closed-loop power control mode, enhances the effect of downlink closed-loop power control when the quality of uplink and downlink links is suddenly reduced at the same time, and improves the link maintenance performance of closed-loop power control in the TD-SCDMA system.
Claims (7)
1. A downlink power control method in TD-SCDMA system is a closed loop downlink power control method, which is characterized in that the method comprises the following steps:
step A, a base station performs a closed-loop downlink power control process according to a conventional power control step length, and simultaneously detects the signal-to-noise ratio of an uplink power control feedback coding combined transmission channel, wherein the uplink power control feedback coding combined transmission channel carries a power control command;
b, the base station detects whether the quality of the uplink is in a deterioration state, if so, the base station is switched to a downlink recovery period, and during the recovery period, the base station responds to the power control command of power up-regulation by a recovery step length and responds to the power control command of power down-regulation by a conventional step length; if not, the base station performs a closed-loop downlink power control process according to the conventional power control step length.
2. The method of claim 1, wherein the step B further comprises:
step B1, the base station judges the quality of the signal-to-noise ratio of the detected uplink coding combined transmission channel, if the quality of an uplink is considered to be in a deterioration state, the step B2 is carried out, otherwise, the step B3 is carried out;
step B2, the base station is switched into a downlink recovery period, during the recovery period, the base station responds to the power control command of power up-regulation by a recovery step length, the base station responds to the power control command of power down-regulation by a conventional step length, and the step B4 is carried out;
step B3, the base station performs a closed-loop downlink power control process according to the conventional power control step length, and the step A is performed;
step B4, the base station judges whether the downlink recovery period is finished, if so, the step A is carried out, otherwise, the step B5 is carried out;
and step B5, the base station judges the quality of the detected signal-to-noise ratio of the uplink coding combined transmission channel, if the quality of the uplink is recovered, the step A is carried out, otherwise, the step B2 is carried out.
3. The method of claim 2, wherein in the step B1, the base station determines whether the downlink quality is in a degraded state according to the following method:
step B11, performing data smoothing operation on the detected instantaneous signal-to-noise ratio S (n) of the uplink coding combined transmission channel of the nth subframe, wherein p is a forgetting factor:
step B12, mixing
Compared with the threshold T1, if
If the time length of the subframe D1 is less than the threshold T1 continuously, the step B13 is carried out, otherwise, the step B11 is carried out;
step B13, regarding the uplink quality as being in a deteriorated state, and proceeding to step B11;
the thresholds D1 and T1 in the above steps are obtained through simulation according to the wireless environment.
4. The method of claim 2, wherein in step B4, the base station determines whether the uplink quality has been recovered according to the following method:
step B41, the data smoothing operation is carried out on the detected instantaneous signal-to-noise ratio S (n) of the uplink coding combined transmission channel of the nth subframe, wherein p is a forgetting factor:
step B42, mixing
Compared with the threshold T2, if
If the time length of the D2 subframe is continuously greater than the threshold T2, proceeding to step B43, otherwise, proceeding to step B41;
step B43, regarding the uplink quality recovery, and proceeding to step B41;
the thresholds D2 and T2 in the above steps are obtained by simulation according to the wireless environment.
5. The method for controlling downlink power in TD-SCDMA system according to claim 2, 3 or 4, characterized in that in the step B2, the recovery step after the base station enters the recovery period is larger than the conventional step.
6. The method of claim 5 wherein the recovery step size is twice as large as the conventional step size.
7. The method according to claim 2, 3 or 4 for controlling downlink power in TD-SCDMA system, wherein in the step B2, the downlink recovery period is obtained by simulation and test according to the wireless environment, and the value range is 20 ms-200 ms.
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| CN2007101277011A CN101132207B (en) | 2007-03-09 | 2007-06-18 | Descending power control method in TD-CDMA system |
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| CN200710037944.6 | 2007-03-09 | ||
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| CN2007101277011A CN101132207B (en) | 2007-03-09 | 2007-06-18 | Descending power control method in TD-CDMA system |
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| CN102271355A (en) * | 2011-08-16 | 2011-12-07 | 大唐移动通信设备有限公司 | Method and device for determining attenuation switching splicing error of test device |
| CN102843760A (en) * | 2011-06-24 | 2012-12-26 | 普天信息技术研究院有限公司 | Downlink power distribution method in LTE (Long-Term Evolution) system |
| CN102026350B (en) * | 2009-09-23 | 2014-08-13 | 中兴通讯股份有限公司 | Method and terminal for power regulation |
| CN105848187A (en) * | 2016-05-12 | 2016-08-10 | 西北工业大学 | Wireless network link quality evaluation method based on signal-to-noise ration threshold adaptation |
| CN107251449A (en) * | 2015-03-27 | 2017-10-13 | 英特尔Ip公司 | Frame structure design and system in 802.11AX standards for the Power Control based on OFDMA |
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Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100459573B1 (en) * | 2001-08-25 | 2004-12-03 | 삼성전자주식회사 | Apparatus for transmitting/receiving uplink transmission power and high speed downlink shared channel power level in communication system using high speed downlink packet access scheme and method thereof |
| CN100438365C (en) * | 2002-05-09 | 2008-11-26 | 诺基亚西门子通信公司 | Multiple level power control command signaling |
| US7808944B2 (en) * | 2003-11-21 | 2010-10-05 | Interdigital Technology Corporation | Wireless communication method and apparatus for controlling the transmission power of downlink and uplink coded composite transport channels based on discontinuous transmission state values |
| WO2006069487A1 (en) * | 2004-12-30 | 2006-07-06 | Utstarcom Telecom Co., Ltd. | Td-scdma wireless communication system and method of improving downlink power control thereof |
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- 2007-06-18 CN CN2007101277011A patent/CN101132207B/en not_active Expired - Fee Related
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| CN102026350B (en) * | 2009-09-23 | 2014-08-13 | 中兴通讯股份有限公司 | Method and terminal for power regulation |
| CN102843760A (en) * | 2011-06-24 | 2012-12-26 | 普天信息技术研究院有限公司 | Downlink power distribution method in LTE (Long-Term Evolution) system |
| CN102843760B (en) * | 2011-06-24 | 2015-09-16 | 普天信息技术研究院有限公司 | Downlink power distributing method in a kind of LTE system |
| CN102271355A (en) * | 2011-08-16 | 2011-12-07 | 大唐移动通信设备有限公司 | Method and device for determining attenuation switching splicing error of test device |
| CN102271355B (en) * | 2011-08-16 | 2013-12-04 | 大唐移动通信设备有限公司 | Method and device for determining attenuation switching splicing error of test device |
| CN107251449A (en) * | 2015-03-27 | 2017-10-13 | 英特尔Ip公司 | Frame structure design and system in 802.11AX standards for the Power Control based on OFDMA |
| CN107251449B (en) * | 2015-03-27 | 2021-09-28 | 英特尔公司 | Frame structure design and system for OFDMA-based power control in the 802.11AX standard |
| CN105848187A (en) * | 2016-05-12 | 2016-08-10 | 西北工业大学 | Wireless network link quality evaluation method based on signal-to-noise ration threshold adaptation |
| CN105848187B (en) * | 2016-05-12 | 2019-01-08 | 西北工业大学 | Based on the adaptive wireless network links method for evaluating quality of snr threshold |
| CN112514524A (en) * | 2018-07-27 | 2021-03-16 | 华为技术有限公司 | C-DRX mode link failure recovery |
| CN112514524B (en) * | 2018-07-27 | 2023-05-02 | 华为技术有限公司 | Link failure recovery for C-DRX mode |
| US12082285B2 (en) | 2018-07-27 | 2024-09-03 | Huawei Technologies Co., Ltd. | Link failure recovery in C-DRX mode |
| US12133276B2 (en) | 2018-07-27 | 2024-10-29 | Huawei Technologies Co., Ltd. | Link failure recovery in C-DRX mode |
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