CN1859026A - Power control method for physical signal - Google Patents

Abstract

This invention discloses a power control method for physical signals, in which, when a base station transmits data to the UE, it calculates the times of ACK/NACK in the ACK/NACK domain to the information fed back by the UE to estimate the actual test probability of HS-SCCH, which adjusts the emission power of the HS-SCCH by the difference of the actual test probability and the target tst probability.

Description

A kind of circule power control method of physical signalling

Technical field

The present invention relates to the WCDMA communication system, relate in particular to the high speed downlink packet access technology in the WCDMA communication system.

Background technology

The full name of HSDPA is that high speed downlink packet inserts (High Speed Downlink PacketAccess), it is the key property of WCDMA technology the 5th version, retransmit (HARQ) by adaptive modulation and coding (AMC), mixing, and the series of key techniques such as fast dispatch of base station, realized descending high speed data transfer.The HSDPA down physical channel is included in the HS-PDSCH channel of downlink transmission data information and the HS-SCCH channel of transmission Downlink Control Information.

The speed of HS-SCCH channel is 60kbps, and spreading factor is fixed as SF=128, and the long 2ms of every subframe is made of three time slots.Wherein, first time slot has carried the sign indicating number collection and the modulation system information of high speed downlink shared channel HS-DSCH channel, and second and third time slot has carried information such as transmission block size, HARQ process, redundancy and planisphere version, new data indication, the UE ID of HS-DSCH channel.Agreement 3GPP TS25.212 has provided detailed description to beared information and the cataloged procedure of HS-SC CH.

Cover owing to use " corresponding UE ID " that coded-bit is added in the cataloged procedure of HS-SCCH, therefore the HS-SCCH information that is sent has in fact also comprised the UE ID that should receive corresponding HS-DSCH data.Therefore, have only HS-SCCH correctly to be detected, UE is just meaningful to the demodulation of corresponding HS-DSCH.Otherwise the flase drop of HS-SCCH channel or omission will cause the waste of UE power resource or the decline of throughput of system.So the power configuration of HS-SCCH should guarantee that the detection probability of HS-SCCH meets certain requirements.But because HS-SCCH and HS-DSCH Channel Sharing transmitting power, the base station is the demand that at first satisfies the HS-SCCH channel when the transmitting power of configuration HS-SCCH and HS-DSCH, just gives HS-DSCH remaining HSDPA transmit power allocations then.Therefore, if HS-SCCH has taken more transmitting power, thereby certainly will cause the available launch power reduction of HS-DSCH also to cause throughput of system to descend.

So, the transmitting power of HS-SCCH should reach as far as possible little under the condition of certain detection probability, thereby neither can cause correctly demodulation of HS-DSCH, also can not cause HS-DSCH available horsepower resource to diminish because of HS-SCCH takies more transmitting power because of HS-SCCH detects failure.Consider that the received signal to noise ratio that near-far interference and channel fading cause changes, should carry out power control HS-SCCH.Agreement 3GPPTS25.214 does not provide clearly regulation to the Poewr control method of HS-SCCH, and the base station can be chosen flexibly.

Prior art one: in order to guarantee the correct reception of HS-SCCH in whole HSDPA coverage, each user's HS-SCCH transmitted power can follow the TPC order of DPCH channel to adjust:

P _HS-SCCH＝P _DPCHt+Δ _{HS-SCCH_DPCH}

Wherein, P _HS-SCCHAnd P _DPCHBe respectively the transmitting power of HS-SCCH and DPCH

Δ _{HS-SCCH_DPCH}Expression HS-SCCH is with respect to the power bias value of DPCH

According to the DPCH channel TPC order of receiving, if the DPCH channel need increase transmitting power, then HS-SCCH also increases transmitting power; Otherwise, then reduce transmitting power.

But, on the one hand, because the Transmission Time Interval TTI=2ms of HS-SCCH, and there are not interframe, intra-frame interleaving operation, therefore and TTI=20ms and the DPCH channel that exists interframe, intra-frame interleaving to operate compares, when HS-SCCH follows DPCH to carry out power control according to the TPC order of UE feedback, there is not the power control gain as a rule substantially, sometimes performance even also can descend.

On the other hand, when HS-SCCH followed DPCH to carry out power control, because the HS-SCCH channel does not have soft handover, and the soft handover gain of descending DPCH channel made its power demand when soft handover reduce.So when UE was in soft changing state, in order to guarantee the successful detection of HS-SCCH channel, the HS-SCCH transmitting power should increase on the basis of non-soft handover to some extent with respect to the bias of DPCH.That is to say when HS-SCCH follows DPCH to carry out power control, need whether be in the corresponding power bias value of soft changing state adjustment according to UE.Though but the control of the power of HS-SCCH is responsible for by the base station, its power bias but is provided with by RNC, therefore whether RNC should be in soft changing state according to the user power bias of HS-SCCH in the base station is upgraded, to guarantee the correct detection of HS-SCCH at soft handover.In addition, when UE is in soft changing state, the descending TPC order of its transmission is that the channel quality to a plurality of sub-districts carries out comprehensive result, if there is a sub-district need reduce transmitting power, then UE just sends the TPC command word of reduction DPCH channel emission powers to all sub-districts.The ineffectivity of when therefore, " comprehensive " of TPC command word also can cause UE to be in soft changing state HS-SCCH being carried out power control.

To sum up, when HS-SCCH followed DPCH to carry out power control according to the TPC order of UE feedback, not only power control poor-performing as a rule, and its power control parameters etc. also was subjected to UE whether to be in the influence of soft changing state.

Prior art two: because the channel quality indicator CQI that UE reports based on the signal to noise ratio snr of HS-DSCH, therefore also can reflect the SNR of current HS-SCCH channel really.So prior art two is to utilize CQI that the transmitting power of HS-SCCH is controlled.

Whether be in soft handover though need not to distinguish UE when utilizing CQI that HS-SCCH is carried out power control, under different Channel Transmission environment, but difference is very big for the HS-SCCH transmitting power adjustment amount of same CQI correspondence.That is to say that the parameter value when carrying out power control based on CQI depends on concrete Channel Transmission environment.In addition, therefore also longer relatively to the cycle that HS-SCCH carries out power control because report cycle and the time delay of CQI are longer based on CQI, can't effectively resist rapid fading.

Summary of the invention

The present invention is directed to the shortcoming of above-mentioned prior art, proposed a kind of circule power control method of physical signalling,

May further comprise the steps:

When A, base station send data to UE, detect the number of times of this UE feeding back ACK or NACK;

B, calculate the actual detected probability according to the number of times of described UE feeding back ACK or NACK and total number of times that detects;

C, the transmitting power of HS-SCCH is adjusted according to the difference between actual detected probability and the target detection probability.

Further, described steps A comprises: default total number of times m that detects, and the feedback of base station detection UE m time, and add up the number of times that detects ACK or NACK in this m time.

Further, described steps A comprises: detect the feedback of UE within a certain period of time, and add up total detection number of times and the number of times that detects ACK or NACK.

Described actual detected probability is the result of the number of times of described UE feeding back ACK or NACK divided by total detection number of times.

Base station described in the steps A sends data to UE: the base station sends data by HS-DSCH to UE; The number of times of described UE feeding back ACK or NACK is: UE is the number of times of ACK or NACK in the ACK/NACK territory by the information of HS-DPCCH transmission.

Step C is described to be adjusted into according to the transmitting power of the difference between actual detected probability and the target detection probability to HS-SCCH: if the actual detected probability less than target detection probability, then increases the transmitting power of HS-SCCH; Otherwise reduce the transmitting power of HS-SCCH.

Wherein, the calculating formula to the adjustment amount of the transmitting power of HS-SCCH is: $\mathrm{\Δ}=(1-\mathrm{\α})(\frac{1-\mathrm{DetectionProb}}{1-T\arg \mathrm{etProb}}-1)\×\mathrm{Step},$ In the formula, parameter alpha is the power adjusting factor of value between [0,1], and DetectionProb is the actual detected probability of statistics gained, and TargetProb is a target detection probability, and parameter S tep is that set power is adjusted step-length, and unit is dB.

The present invention can satisfy effective saving system power resource under the Qos prerequisite of HS-SCCH, and is not subjected to UE whether to be in the influence of soft handover and channel circumstance.

Description of drawings

Fig. 1 is the flow chart of the specific embodiment of the invention.

Embodiment

For make purpose of the present invention, technical scheme, and advantage clearer, below by specific embodiment, in conjunction with the accompanying drawings, the present invention is described in more detail.

Have only when UE correctly detects, just can determine to send out an ACK or a NACK according to the cyclic redundancy check (CRC) decode results of HS-DSCH channel behind the demodulation HS-SCCH, otherwise will send discontinuous transmission DTX in corresponding ACK/NACK territory.That is to say, if HS-DPCCH in its ACK/NACK territory, send for ACK or NACK, represent that then UE correctly detects HS-SCCH; Otherwise expression HS-SCCH detects failure.Therefore, a preferred embodiment of the present invention proposes: the HS-DSCH channel is passed through when UE sends data in the base station, ACK/NACK territory to the HS-DPCCH channel is added up, thereby estimate the transmitting power of the actual detected probability adjustment HS-SCCH of HS-SCCH, promptly the base station utilizes the real-time Qos of HS-SCCH that it is carried out power control.When the actual Qos of HS-SCCH is better than desired value, this method will reduce the transmitting power of HS-SCCH, thereby satisfy effective system power resource of saving under the Qos prerequisite of HS-SCCH; When the actual Qos of HS-SCCH was inferior to desired value, the transmitting power that this method will increase HS-SCCH satisfied the Qos requirement of HS-SCCH.Obviously, this circule power control method is not subjected to UE whether to be in the influence of soft handover and channel circumstance.

Fig. 1 is the flow chart of present embodiment, and its step is as follows:

1, the base station when UE sends data, is detected the ACK/NACK territory of the HS-DPCCH information of this UE feedback by HS-DSCH.

This detection can detect in certain number of times, also can detect within a certain period of time.

If detect in certain number of times, detecting, then to preestablish total number of times that detects, as 30.The base station is detected the ACK/NACK territory 30 times of the HS-DPCCH information of UE feedback altogether, and is the number of times of ACK or NACK in the statistics ACK/NACK territory.

If detect within a certain period of time, the ACK/NACK territory of the HS-DPCCH information of UE feedback need during this period of time be detected in the base station, and adds up in total detection number of times and the ACK/NACK territory number of times for ACK or NACK.

2, calculate the actual detected probability.

Be the number of times of ACK or NACK/always detect number of times * 100% in actual detected probability=ACK/NACK territory.

For example, the base station is detected the ACK/NACK territory 30 times of the HS-DPCCH information of UE feedback altogether, and detects that the number of times for ACK or NACK is 24 times in the ACK/NACK territory, and then the actual detected probability is: 24/30 * 100%=80%.

3, according to the difference of actual detected probability and target detection probability, the transmitting power of HS-SCCH is adjusted.

If the actual detected probability less than target detection probability, then increases the transmitting power of HS-SCCH; Otherwise reduce the transmitting power of HS-SCCH.

Target detection probability is decided according to actual conditions, and industry has unified demand, and general the requirement is 98%.

Adjustment amount Δ to the transmitting power of HS-SCCH is obtained by following formula:

$\mathrm{\Δ}=(1-\mathrm{\α})(\frac{1-\mathrm{DetectionProb}}{1-T\arg \mathrm{etProb}}-1)\×\mathrm{Step}$

In the formula, parameter alpha is the power adjusting factor of value between [0,1], DetectionProb is the actual detected probability of statistics gained, and TargetProb is a target detection probability, and parameter S tep is that set power is adjusted step-length, size is decided according to actual conditions, and unit is dB.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.

Claims (7)

1, a kind of circule power control method of physical signalling is characterized in that, this method may further comprise the steps:

When A, base station send data to UE, detect the number of times of this UE feeding back ACK or NACK;

B, calculate the actual detected probability according to the number of times of described UE feeding back ACK or NACK and total number of times that detects;

C, the transmitting power of HS-SCCH is adjusted according to the difference between actual detected probability and the target detection probability.

2, a kind of circule power control method of physical signalling according to claim 1 is characterized in that described steps A comprises: default total number of times m that detects, feedback m time of UE is detected in the base station, and adds up the number of times that detects ACK or NACK in this m time.

3, a kind of circule power control method of physical signalling according to claim 1 is characterized in that described steps A comprises: detect the feedback of UE within a certain period of time, and add up total detection number of times and detect the number of times of ACK or NACK.

As the circule power control method of a kind of physical signalling as described in claim 2 or 3, it is characterized in that 4, the described actual detected probability of step B is that the number of times of described UE feeding back ACK or NACK is divided by total result who detects number of times.

5, a kind of circule power control method of physical signalling according to claim 1 is characterized in that, base station described in the steps A sends data to UE and is: the base station sends data by HS-DSCH to UE; The number of times of described UE feeding back ACK or NACK is: UE is the number of times of ACK or NACK in the ACK/NACK territory by the information of HS-DPCCH transmission.

6, a kind of circule power control method of physical signalling according to claim 1, it is characterized in that, step C is described to be adjusted into according to the transmitting power of the difference between actual detected probability and the target detection probability to HS-SCCH: if the actual detected probability less than target detection probability, then increases the transmitting power of HS-SCCH; Otherwise reduce the transmitting power of HS-SCCH.

7, as the circule power control method of a kind of physical signalling as described in the claim 6, it is characterized in that, be the calculating formula of the adjustment amount of the transmitting power of HS-SCCH: $\mathrm{\Δ}=(1-\mathrm{\α})(\frac{1-\mathrm{DetectionProb}}{1-T\arg \mathrm{etProb}}-1)\×\mathrm{Step},$ In the formula, parameter alpha is the power adjusting factor of value between [0,1], and DetectionProb is the actual detected probability of statistics gained, and TargetProb is a target detection probability, and parameter S tep is that set power is adjusted step-length, and unit is dB.

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