CN101179307A - Downlink power control method and system - Google Patents

Abstract

The invention discloses a method for controlling a downlink power and a system thereof. A base station detects the signal-to-interference ratio of an uplink feedback encoding transmission channel corresponding to a downlink encoding transmission channel, wherein the uplink feedback encoding transmission channel carries the power control command. Comparing the detected signal-to-interference ratio with a threshold value; if the signal-to-interference ratio is more than or equal to the threshold value, the power control command is decoded and the transmitting power of the downlink encoding transmission channel is adjusted according to the decoded power control command; if the detected signal-to-interference ratio is less than the threshold value, the power control command is neglected. The invention strengthens the downlink power control when the uplink signal is weak, and increases the ability of the UE to resist the bad wireless environment and the effect of the downlink power control.

Description

Method for controlling downlink power and system

Technical field

The present invention relates to wireless communication technology, relate in particular to a kind of method for controlling downlink power and system.

Background technology

The descending power control technology is widely used in comprising that TD-SCDMA (TimeDivision-Synchronous Code Division Multiple Access, TD SDMA) system is in each interior standard 3-G (Generation Three mobile communication system).

The downlink power control that is applied in the TD-SCDMA system is a closed loop procedure, its basic process is as follows: subscriber equipment receives from after the signal of base station, measure the SIR (signal interference ratio) of downstream signal, sir measurement value according to downstream signal determines whether that needs increase or reduce the downstream signal transmitting power of base station, and produces the power control command that corresponding expression requires base station transmitting power increase and decrease (Up/Down).Subscriber equipment passes to the base station with power control command by up power control feedback channel, and down transmitting power is suitably adjusted according to power control command after receiving power control command in the base station.

In the downlink closed-loop power control, the mechanism that is used to control down transmitting power is designed to increase on the basis of current transmitting power or reduce certain power and adjust step-length, even subscriber equipment passes to the power control commands word of base station owing to there is certain error probability in the reason that wireless channel transmits by up feedback channel like this, as long as the error of transmission of power control commands word is in certain degree, the mechanism that increases and decreases power with step-length unit can guarantee that still downlink power control is controlled at downstream signal on certain subscriber equipment signal receiving quality level.

But for certain user's equipment, up channel from the subscriber equipment to the base station and the down channel from the base station to the subscriber equipment may be in more abominable state simultaneously, and when descending channel degradation, subscriber equipment can require the base station in time to increase descending power; But owing to up channel also while variation, make the error rate of the power control commands word in the up power control feedback channel strengthen, after the up channel variation arrives to a certain degree, the error rate of power control commands word will exert an influence to power control, at this moment downlink closed-loop power control process not only can weaken the control effect to descending power, also can aggravate the decline of the signal receiving quality of subscriber equipment when serious, cause the subscriber equipment call drop.

Therefore, need a kind of descending power control solution, can improve descending power control effect.

Summary of the invention

Main purpose of the present invention is to provide a kind of method for controlling downlink power and system, is used for each downlink coding transmission channel is carried out power control, to strengthen the power control effect.

To achieve these goals, according to a first aspect of the invention, the invention provides a kind of method for controlling downlink power.Method for controlling downlink power may further comprise the steps:

Step S102, the signal interference ratio of the up feedback encoding transmission channel corresponding with the downlink coding transmission channel is detected in the base station, and up feedback encoding transmission channel carries power control command;

Step S104 compares detected signal interference ratio and threshold value, if more than or equal to threshold value, then proceeds to step S106, otherwise proceeds to step S108;

Step S106, the decoding power control command, and adjust the transmitting power of downlink coding transmission channel according to the power control command that decoding back obtains;

Step S108 ignores power control command.

Preferably, in step S108, the power control command of not decoding.

Can obtain threshold value by emulation according to wireless environment.

In step S108, the base station can keep the transmitting power of downlink coding transmission channel constant.

In step S108, the base station can be adjusted the transmitting power of downlink coding transmission channel according to following formula:

P(k)＝P(k-1)+S(k)

Wherein, P (k-1) is the transmitting power of current subframe, and P (k) is the transmitting power of next subframe, and S (k) is the power adjustment on k the subframe, wherein, determines S (k) according to following formula:

$S\left(k\right)=\left\{\begin{array}{cc}\mathrm{Step}& \mathrm{ifSum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{ifSum}\left(k\right)+\mathrm{Step}>\mathrm{Power}\_\mathrm{Limit}\end{array}\right.$

Wherein, $\mathrm{Sum}\left(k\right)=\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right),$ If a certain subframe algorithm execution in step S106, S (k)=0 then, Step are the step-lengths of using when adjusting power, Power_Limit is that the maximum power when adjusting power is adjusted quantitative limitation, and WSize is to be that the window of unit is long with the subframe.

Can obtain parameter S tep, Power_Limit, WSize by emulation according to wireless environment.

To achieve these goals, according to a second aspect of the invention, the invention provides a kind of down power controlling system.Down power controlling system comprises: the base station; The signal interference ratio detection module is positioned at base station side, is used to detect the signal interference ratio of the up feedback encoding transmission channel corresponding with the downlink coding transmission channel, and up feedback encoding transmission channel carries power control command; Power is adjusted judging module, be positioned at base station side, be used for detected signal interference ratio and threshold value are compared, if signal interference ratio is greater than threshold value, then adjudicate the decoding power control command, and adjust the transmitting power of downlink coding transmission channel according to the power control command that decoding back obtains, if signal interference ratio is not more than threshold value, then power control command is ignored in judgement.

Preferably, power is adjusted judging module and adjudicate the power control command of not decoding when signal interference ratio is not more than threshold value.

Threshold value can obtain by emulation according to wireless environment.

Alternatively, adjust the judging module judgement at power and ignore under the situation of power control command, the base station keeps the transmitting power of downlink coding transmission channel constant.

Alternatively, adjust the judging module judgement at power and ignore under the situation of power control command, the transmitting power of downlink coding transmission channel is adjusted in the base station according to following formula:

P(k)＝P(k-1)+S(k)

Wherein, P (k-1) is the transmitting power of current subframe, and P (k) is the transmitting power of next subframe, and S (k) is the power adjustment on k the subframe, wherein, determines S (k) according to following formula:

$S\left(k\right)=\left\{\begin{array}{cc}\mathrm{Step}& \mathrm{ifSum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{ifSum}\left(k\right)+\mathrm{Step}>\mathrm{Power}\_\mathrm{Limit}\end{array}\right.$

Wherein, $\mathrm{Sum}\left(k\right)=\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right),$ If a certain subframe algorithm execution in step S106, S (k)=0 then, Step are the step-lengths of using when adjusting power, Power_Limit is that the maximum power when adjusting power is adjusted quantitative limitation, and WSize is to be that the window of unit is long with the subframe.

Parameter S tep, Power_Limit, WSize can obtain by emulation according to wireless environment.

By technique scheme, the control of the descending power when relatively poor strengthens to upward signal in the present invention, has improved the ability that UE resists abominable wireless environment, has improved the effect of descending power control.

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:

Fig. 1 is the flow chart according to method for controlling downlink power of the present invention; And

Fig. 2 is the block diagram according to down power controlling system of the present invention.

Embodiment

Describe the present invention below with reference to the accompanying drawings in detail.

With reference to Fig. 1, method for controlling downlink power according to the present invention may further comprise the steps:

Step S102, the signal interference ratio of the up feedback encoding transmission channel corresponding with the downlink coding transmission channel is detected in the base station, and up feedback encoding transmission channel carries power control command.

Step S104 compares detected signal interference ratio and threshold value, if more than or equal to threshold value, then proceeds to step S106, otherwise proceeds to step S108.

Can obtain threshold value by emulation according to wireless environment.

Step S106, the decoding power control command, and adjust the transmitting power of downlink coding transmission channel according to the power control command that decoding back obtains.

Step S108 ignores power control command.

Preferably, the power control command of not decoding.

The base station can keep the transmitting power of downlink coding transmission channel constant.

The base station can be adjusted the transmitting power of downlink coding transmission channel according to following formula:

P(k)＝P(k-1)+S(k)

Wherein, P (k-1) is the transmitting power of current subframe, and P (k) is the transmitting power of next subframe, and S (k) is the power adjustment on k the subframe, wherein, determines S (k) according to following formula:

$S\left(k\right)=\left\{\begin{array}{cc}\mathrm{Step}& \mathrm{ifSum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{ifSum}\left(k\right)+\mathrm{Step}>\mathrm{power}\_\mathrm{Limit}\end{array}\right.$

Wherein, $\mathrm{Sum}\left(\text{k}\right)\text{=}\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right),$ If a certain subframe algorithm execution in step S106, S (k)=0 then, Step are the step-lengths of using when adjusting power, Power_Limit is that the maximum power when adjusting power is adjusted quantitative limitation, and WSize is to be that the window of unit is long with the subframe.

Can obtain parameter S tep, Power_Limit, WSize by emulation according to wireless environment.For example, the Step scope is 1～3dB, and the Power_Limit scope is 5～10dB, 10～50 subframes of WSize scope.

With reference to Fig. 2, down power controlling system 10 according to the present invention comprises: base station 20; Signal interference ratio detection module 30 is positioned at base station 20 sides, is used to detect the signal interference ratio of the up feedback encoding transmission channel corresponding with the downlink coding transmission channel, and up feedback encoding transmission channel carries power control command; Power is adjusted judging module 40, be positioned at base station 20 sides, be used for detected signal interference ratio and threshold value are compared, if signal interference ratio is greater than threshold value, then adjudicate the decoding power control command, and adjust the transmitting power of downlink coding transmission channel according to the power control command that decoding back obtains, if signal interference ratio is not more than threshold value, then power control command is ignored in judgement.

Preferably, power is adjusted judging module 40 and adjudicate the power control command of not decoding when signal interference ratio is not more than threshold value.

Threshold value can obtain by emulation according to wireless environment.

Alternatively, adjust judging module 40 judgements at power and ignore under the situation of power control command, base station 20 keeps the transmitting power of downlink coding transmission channel constant.

Alternatively, adjust judging module 40 judgements at power and ignore under the situation of power control command, the transmitting power of downlink coding transmission channel is adjusted in base station 20 according to following formula:

P(k)＝P(k-1)+S(k)

Wherein, P (k-1) is the transmitting power of current subframe, and P (k) is the transmitting power of next subframe, and S (k) is the power adjustment on k the subframe, wherein, determines S (k) according to following formula:

$S\left(k\right)=\left\{\begin{array}{cc}\mathrm{Step}& \mathrm{ifSum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{ifSum}\left(k\right)+\mathrm{Step}>\mathrm{power}\_\mathrm{Limit}\end{array}\right.$

Wherein, $\mathrm{Sum}\left(k\right)=\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right),$ If a certain subframe algorithm execution in step S106, S (k)=0 then, Step are the step-lengths of using when adjusting power, Power_Limit is that the maximum power when adjusting power is adjusted quantitative limitation, and WSize is to be that the window of unit is long with the subframe.

Parameter S tep, Power_Limit, WSize can obtain by emulation according to wireless environment.For example, the Step scope is 1～3dB, and the Power_Limit scope is 5～10dB, 10～50 subframes of WSize scope.

The present invention relates to wireless communication technology field, relate in particular to the method for controlling downlink power that strengthens in a kind of TD-SCDMA system.The present invention specifically is achieved in that

For the arbitrary downlink coding transmission channel (CCTrCH, Coded Composite Transport Channel) that needs its power of base stations control that exists in the system, do following steps in each subframe and calculate:

Step 1, the signal interference ratio (SIR, Signal Interference Ratio) of the up feedback encoding transmission channel that carry power control command (TPC, Transmission Power Control) corresponding with this controlled downlink coding transmission channel is detected in the base station;

Step 2 compares signal interference ratio and the thresholding T that calculates in the step 1, if more than or equal to thresholding T, forwards step 3 to, if less than thresholding T, forwards step 4 to;

Step 3, the power control command that carries in the up feedback encoding transmission channel corresponding of decoding with this controlled downlink coding transmission channel, and, adjust corresponding downstream coding transmission channel transmitting power according to the power control command that the decoding back obtains;

Step 4, the power control command of not decoding and carrying in the up feedback encoding transmission channel corresponding with this controlled downlink coding transmission channel, base station are ignored the power control command of sending out on the subscriber equipment and are controlled the transmitting power of corresponding downlink coding transmission channel according to certain strategy.

" base station is ignored the power control command of sending out on the subscriber equipment and controlled the transmitting power of corresponding downlink coding transmission channel according to certain strategy " of above-mentioned step 4 has two kinds of specific implementation methods, is described as follows:

Scheme one, base station are ignored the power control command of sending out on the subscriber equipment, and the base station keeps corresponding controlled downlink coding transmission channel (CCTrCH) transmitting power constant;

Scheme two, base station are ignored the power control command of sending out on the subscriber equipment, and the base station increases or keep the transmitting power of corresponding controlled downlink coding transmission channel in the following manner:

The transmitting power P (k) of the transmitting power P (k-1) of current (being labeled as k-1) subframe (sub-frame) to next (being labeled as k) subframe adjusted according to formula (1) in the base station

P(k)＝P(k-1)+S(k)

(1)

S (k) is the power adjustment on K the subframe, determines according to formula (2),

$S\left(k\right)=\left\{\begin{array}{cc}\mathrm{Step}& \mathrm{ifSum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{ifSum}\left(k\right)+\mathrm{Step}>\mathrm{power}\_\mathrm{Limit}\end{array}\right.---(2-1)$

$\mathrm{Sum}\left(k\right)=\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right)---(2-2)$

If a certain subframe algorithm is carried out the branch of above-mentioned steps three, above-mentioned S (k)=0.

The step-length that parameter S tep wherein uses when being each utilization (2-1) formula adjustment power; Power_Limit is that to adjust quantitative limitation, WSize be to be that the window of unit is long with the subframe to the maximum power of utilization (2-1) formula when adjusting power.

Parameter S tep, Power_Limit, WSize obtain by emulation according to wireless environment.

Signal interference ratio comparison threshold T described in the step 2 obtains by emulation according to wireless environment.

The base station is carried out power control according to above-mentioned downlink power control mode to each the downlink coding transmission channel in the system, to strengthen the power control effect.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (12)

1. a method for controlling downlink power is characterized in that, may further comprise the steps:

Step S102, the signal interference ratio of the up feedback encoding transmission channel corresponding with the downlink coding transmission channel is detected in the base station, and described up feedback encoding transmission channel carries power control command;

Step S104 compares detected described signal interference ratio and threshold value, if more than or equal to described threshold value, then proceeds to step S106, otherwise proceeds to step S108;

Step S106, the described power control command of decoding, and the power control command that afterwards obtains according to decoding is adjusted the transmitting power of described downlink coding transmission channel;

Step S108 ignores described power control command.

2. method for controlling downlink power according to claim 1 is characterized in that, in step S108, and the described power control command of not decoding.

3. method for controlling downlink power according to claim 1 is characterized in that, obtains described threshold value according to wireless environment by emulation.

4. method for controlling downlink power according to claim 1 is characterized in that, in step S108, described base station keeps the transmitting power of described downlink coding transmission channel constant.

5. method for controlling downlink power according to claim 1 is characterized in that, in step S108, the transmitting power of described downlink coding transmission channel is adjusted in described base station according to following formula:

P(k)＝P(k-1)+S(k)

Wherein, P (k-1) is the transmitting power of current subframe, and P (k) is the transmitting power of next subframe, and S (k) is the power adjustment on k the subframe, wherein, determines S (k) according to following formula:

$S\left(k\right)=\left\{\begin{array}{ccc}\mathrm{Step}& \mathrm{if}& \mathrm{Sum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{if}& \mathrm{Sum}\left(k\right)+\mathrm{Step}>\mathrm{Power}\_\mathrm{Limit}\end{array}\right.$

Wherein, $\mathrm{Sum}\left(k\right)=\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right),$ If a certain subframe algorithm execution in step S106, S (k)=0 then, Step are the step-lengths of using when adjusting power, Power_Limit is that the maximum power when adjusting power is adjusted quantitative limitation, and WSize is to be that the window of unit is long with the subframe.

6. method for controlling downlink power according to claim 5 is characterized in that, obtains parameter S tep, Power_Limit, WSize according to wireless environment by emulation.

7. a down power controlling system is characterized in that, comprising:

The base station;

The signal interference ratio detection module is positioned at described base station side, is used to detect the signal interference ratio of the up feedback encoding transmission channel corresponding with the downlink coding transmission channel, and described up feedback encoding transmission channel carries power control command;

Power is adjusted judging module, be positioned at described base station side, be used for detected described signal interference ratio and threshold value are compared, if described signal interference ratio is greater than described threshold value, then adjudicate the described power control command of decoding, and adjust the transmitting power of described downlink coding transmission channel according to the power control command that decoding back obtains, if described signal interference ratio is not more than described threshold value, then described power control command is ignored in judgement.

8. down power controlling system according to claim 7 is characterized in that, described power is adjusted judging module and adjudicate the described power control command of not decoding when described signal interference ratio is not more than described threshold value.

9. down power controlling system according to claim 7 is characterized in that described threshold value obtains by emulation according to wireless environment.

10. down power controlling system according to claim 7 is characterized in that, adjusts the judging module judgement at described power and ignores under the situation of described power control command, and described base station keeps the transmitting power of described downlink coding transmission channel constant.

11. down power controlling system according to claim 7 is characterized in that, adjusts the judging module judgement at described power and ignores under the situation of described power control command, the transmitting power of described downlink coding transmission channel is adjusted in described base station according to following formula:

P(k)＝P(k-1)+S(k)

Wherein, P (k-1) is the transmitting power of current subframe, and P (k) is the transmitting power of next subframe, and S (k) is the power adjustment on k the subframe, wherein, determines S (k) according to following formula:

$S\left(k\right)=\left\{\begin{array}{ccc}\mathrm{Step}& \mathrm{if}& \mathrm{Sum}\left(k\right)+\mathrm{Step}\≤\mathrm{Power}\_\mathrm{Limit}\\ 0& \mathrm{if}& \mathrm{Sum}\left(k\right)+\mathrm{Step}>\mathrm{Power}\_\mathrm{Limit}\end{array}\right.$

Wherein, $\mathrm{Sum}\left(k\right)=\underset{i=k-\mathrm{WSize}}{\overset{k-1}{\mathrm{\Σ}}}S\left(i\right),$ If a certain subframe algorithm execution in step S106,

S (k)=0 then, Step are the step-lengths of using when adjusting power, and Power_Limit is that the maximum power when adjusting power is adjusted quantitative limitation, and WSize is to be that the window of unit is long with the subframe.

12. down power controlling system according to claim 11 is characterized in that, parameter S tep, Power_Limit, WSize obtain by emulation according to wireless environment.

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