CN101895976A - LTE-Advanced system-based uplink power adjustment method - Google Patents

Abstract

The invention provides an uplink power adjustment method, which is applied to an LTE-Advanced system adopting a frequency spectrum polymerization technology and belongs to a resource distribution part of uplink subcarrier power. The invention mainly comprises the following steps: firstly, calculating out the TPC initial power PPUSCH, k and PPUCCH, K of PUSCH and PUCCH in accordance with an uplink power control formula and judging weather the TPC initial power values meet the limited conditions of maximum transmitting power; and if the result is not qualified with the conditions, carrying out the following steps: adopting a two-classification method or an N-classification method to classify the subcarriers, allocating and adjusting collective adjustment power of offset to the maximum priority and judging whether the adjusting result meets the limited power of the minimum transmitting power. The invention takes the numerical difference of the TPC initial results and the TPC former power to reduce the power, thereby taking into account of the losses of throughput to the extent; the invention considers the minimum transmitting power values of the subcarriers, ensures transmission of PUCCH data and indirectly guarantees utilization rate of the frequency spectrum. The invention is no need of extra control signaling overhead and has simple algorithm, short arithmetic time delay and easy realization.

Description

A kind of uplink power adjustment method based on the LTE-Advanced system

Technical field

The present invention is applied to adopt in the LTE-Advanced system of spectrum aggregating technology, belongs to uplink sub-carrier power resource allocation part.

Background technology

LTE-A (Long Term Evolution-Advanced, LTE-A) system's minimum bandwidth of system's support is 20MHz, maximum bandwidth reaches 100MHz.Consider existing spectrum allocation may mode and planning, in order to support the requirement of so big bandwidth, 3GPP has proposed the employing spectrum aggregating, and (spectrum aggregation, SA) technology solves the demand of band resource.Spectrum aggregating is the technology that a plurality of continuous or discrete LTE carrier extend can be become the transmission carrier wave of LTE-A system.

The uplink power control of employing SA technology and Release's ' 8 is similar in the LTE-Advanced system, with reference to " 3GPP Long Term Evolution (LTE) know-why and system design ", Shen Jia, ppll1-113, calculate subcarrier (component carrier respectively according to formula (1) and (2), CC) PUSCH and the power of PUCCH

P _PUSCH，k＝10·log ₁₀M _PUSCH(k)+P _{0_PUSCH}(k)+α(k)·PL(k)+Δ _TF(k)+f(k)(1)

P _PUCCH，k＝P _{0_PUCCH}(k)+PL(k)+h(·)+Δ _{F_PUCCH}(·)+g(k)(2)

(1) in, k is the label of CC, M _PUSCHBe the resource block number of PUSCH, P _{0_PUSCH}Be the parameter that the sub-district is specific or UE is specific, α is the specific path compensation coefficient in sub-district, and PL is the path fading loss value of down-run survey, Δ _TFBe the parameter at certain specific MCS (modulation coding mode) of rrc layer appointment, f is the transmitting power control closed loop correction factor relevant function specific with the sub-district by high level control.

(2) in, P _{0_PUCCH}Be the parameter that the sub-district is specific or UE is specific, PL is the path fading loss value of down-run survey, and h is the PUCCH format parameter, Δ _{F_PUCCH}Be the rrc layer designated parameters, g is the transmitting power control closed loop correction factor relevant function specific with the sub-district by high level control.

From formula as can be seen, these parameters are closed loop and open Loop Power control parameter, are determined jointly by base station and UE.

UE has fixing maximum transmission power according to the grade of its cell allocation, i.e. the result of power control must satisfy formula (3):

$\underset{k}{\mathrm{\Σ}}{P}_{{\mathrm{CC}}_k}=\underset{k}{\mathrm{\Σ}}\{P_{\mathrm{PUCCH},k}+P_{\mathrm{PUSCH},k}\}\≤P_{\mathrm{MAX}}---\left(3\right)$

Wherein, P _MAXMaximum transmission power for UE.

When adopting the SA technology, be that a plurality of CC are when being UE service simultaneously, CC carries out uplink transmission power control (transmission power control respectively according to power contorl parameters separately, TPC) calculate, the power initial value that obtains may not satisfy the maximum transmission power requirement, need carry out the power adjustment this moment, promptly reduces the TPC initial power.

Document R1-100201, " ULPC:Simultaneous transmission of PUCCH and PUSCHin case of power limitation ", Motorola, January 2010, power regulating method is reduced three classes: CC equivalent is adjusted, and the CC classification is adjusted and the physical channel classification is adjusted.Wherein amount adjustment method such as CC is meant that all CC reduce power with same offset, owing to do not consider the characteristic of CC, the CC of high spectral efficiency is reduced identical power can cause bigger loss of throughput.Document R1-093395, " ULTransmission Power Control in LTE-A; " Samsung, 2009, certain parameter of the CC that gives chapter and verse simultaneously is as modulation coding mode (Modulation and Coding Scheme, MCS) carry out the method that power is adjusted, in theory can maximize throughput, but the algorithm complex height is bigger than time delay higher and that cause to the requirement of UE.In addition, two kinds of methods are not all considered the minimum emissive power of CC.

Summary of the invention

The initial power of up TPC does not satisfy the problem of UE restriction when the present invention is directed to LTE-Advanced system employing carrier aggregation technology, has proposed a kind of power regulating method of taking into account performance and complexity.

The technical scheme that the present invention takes is:

A kind of uplink power adjustment method at the LTE-Advanced system may further comprise the steps:

Step 1 calculates the PUCCH of subcarrier and the TPC initial power P of PUSCH _{PUCCH, k}And P _{PUSCH, k},

P _PUCCH，k＝P _{0_PUCCH}(k)+PL(k)+h(·)+Δ _{F_PUCCH}(·)+g(k)

P _PUSCH，k＝10·log ₁₀M _PUSCH(k)+P _{0_PUSCH}(k)+α(k)·PL(k)+Δ _TF(k)+f(k)；

Step 2 judges whether the TPC initial power satisfies the maximum transmit power limit condition, if satisfy, promptly

Then jump directly to step 7; Otherwise enter step 3; Wherein k is the label of subcarrier, and K is the number of subcarrier, Be the TPC initial power of subcarrier k, P _MAXMaximum transmission power for UE;

Step 3, the priority of adjustment is determined in classification to subcarrier;

Step 4, calculate the power that needs adjustment:

Step 5 is adjusted side-play amount according to the classification results distribution of step 3, obtains adjusted power

And be made as the priority of adjusted subcarrier minimum; Δ wherein _kFor subcarrier k is CC _kSide-play amount, Δ _kPower/M that=needs are adjusted, M are limit priority set sub-carriers number;

Step 6, definition minimum emissive power ε _k, ε _k=P _{PUCCH, k}, judge adjusted power

Whether satisfy the minimum emissive power restriction, if satisfy, promptly Then go to step 7; Otherwise, be its minimum emissive power with the power setting of not satisfying the subcarrier of minimum emissive power restriction, go to step 4.

Step 7,

Be transmitting power.

Described step 3 sub-carriers classification is divided into two class methods and N class method according to nicety of grading;

Two class methods according to TPC initial power and TPC before the positive and negative of numerical difference between of transmitting power subcarrier is divided into two classes, selecting the non-positive subcarrier of numerical value be the object of preferential adjustment;

N class method according to TPC initial power and TPC before the magnitude classification of difference of transmitting power, from the minus tolerance to the principal-employment, subcarrier is divided into the N level, wherein N is smaller or equal to the number of subcarrier, progression N is many more, it is meticulous more to classify; Numerical difference between is more little, and the category label that is included into is more little, and the priority of adjustment is high more.

The side-play amount methods such as method of adjustment employing of side-play amount in the described step 5, the adjustment side-play amount that promptly subcarrier allocation of same classification is identical.

Advantage of the present invention and good effect are as follows:

1. sort module of the present invention with the TPC initial results of CC and TPC before the numerical difference between of power as the CC feature, the state of description CC that can be simple and comprehensive.

2. the present invention considers the CC feature, and promptly the numerical difference between with power before TPC initial results and the TPC serves as according to reducing power, can to a certain degree taking into account the loss of throughput.

3. the present invention has considered the minimum emissive power value of CC, has guaranteed the transmission of PUCCH data, has guaranteed the availability of frequency spectrum indirectly.

4. algorithm does not need extra control signaling consumption.

5. algorithm is simple, and arithmetic time delay is short, is easy to realize.

Description of drawings

Fig. 1 is the inventive method schematic flow sheet;

Fig. 2 be CC equivalent adjust the algorithm after method and the present invention's simplification throughput ratio.

Embodiment

Below in conjunction with accompanying drawing the present invention is described further.

1. sort module

Sort module is selected the preferential CC that adjusts power.Criteria for classification is the numerical difference between of transmitting power before TPC initial power and the TPC.Up TPC is by cell-specific parameters or common decision such as UE special parameter, path loss, Resources allocation block size, MCS and closed loop correction function, so this module characterizes the CC characteristic with TPC result.The transmitting power numerical difference between illustrates that for just the preceding underpower of TPC to support this transmission, requires it to increase power before TPC initial power and TPC; Otherwise, illustrate that the power before the TPC has surplus capacity, can reduce or keep power.Adjustment strategy of the present invention is the demand that As soon as possible Promising Policy CC increases power, and promptly preferential selection has power CC more than needed to adjust.Be divided into two class methods and N class method according to nicety of grading.

Two class methods according to TPC initial power and TPC before the positive and negative of numerical difference between of transmitting power CC is divided into two classes, selecting the non-positive CC of numerical value be the object of preferential adjustment.

N class method according to TPC initial power and TPC before the magnitude classification of difference of transmitting power, from the minus tolerance to the principal-employment, CC is divided into the N level, wherein N is smaller or equal to the number of CC.Progression N is many more, and it is meticulous more to classify.Numerical difference between is more little, and the category label that is included into is more little, and the priority of adjustment is high more.

2. adjusting module

The CC that adjusting module is selected the sort module result distributes the adjustment side-play amount, thereby target is to reduce the TPC initial power with different coefficients to make final transmitting power satisfy maximum transmit power limit.Side-play amount methods such as adjustment algorithm employing, promptly the CC of same classification distributes identical adjustment side-play amount.

3. minimum power limits module

In order to guarantee that uplink control signaling correctly transmits, definition CC _kMinimum emissive power be ε _k, ε _k=P _{PUCCH, k}Whether the adjusted result of minimum power limits module verification satisfies the minimum power confined condition, satisfied then finish the power adjustment process, otherwise returns adjusting module, satisfies maximum, minimum emissive power restrictive condition up to simultaneously.

Detailed process

The uplink power control detailed process is as follows, and flow chart is seen Fig. 1.

Step 1 calculates the TPC initial power P of PUSCH and PUCCH respectively according to uplink power control formula (1) and (2) _{PUSCH, k}And P _{PUCCH, k}

Step 2 judges whether the TPC initial power satisfies the maximum transmit power limit condition.If satisfy, promptly

Wherein k is the label of CC, and K is the number of CC,

Be CC _kThe TPC initial power, P _MAXMaximum transmission power for UE.Jump directly to step 7; Otherwise, enter step 3.

Step 3, priority (sort module) the selection two class methods of adjustment are determined in classification to CC, go to step 3.1; Select N class method, go to step 3.2.

Step 3.1, (two class methods) be TPC initial power and TPC transmitting power before relatively, and CC is divided into two classes,

$\mathrm{\Δ}{P}_{{\mathrm{CC}}_k}=P_{{\mathrm{CC}}_k}-P_{{\mathrm{CC}}_k}\left[t(i-1)\right]\mathrm{is}\left\{\begin{array}{c}\≤0\\ >0\end{array}\right.(1\≤k\≤K)$

Wherein

Be CC before the TPC _kTransmitting power.

Be classified as preferential adjustment classification,

Be classified as secondary adjustment classification.

Step 3.2, (N class method) be TPC initial power and TPC transmitting power before relatively,

$\mathrm{\Δ}{P}_{{\mathrm{CC}}_k}=P_{{\mathrm{CC}}_k}-P_{{\mathrm{CC}}_k}\left[t(i-1)\right],(1\≤k\≤K)$

According to ascending arrangement Determine CC _kAdjustment order, minimum

Be classified as label and be 1 set, maximum

Be classified as the set that label is N.The span of N is [1, K].

Step 4, calculating needs the power of adjustment to be:

Step 5 is distributed adjustment side-play amount (adjusting module) the set adjustment power the highest to priority according to classification results, and the side-play amount of each subcarrier allocation equates in the set: Δ _kPower/M that=needs are adjusted, wherein Δ _kBe CC _kSide-play amount, M is the CC number of this set.Adjusted power is:

Simultaneously, with adjusted CC _kPriority be made as minimum.

Step 6, (minimum power limits module) is according to the calculating of step 1 CC as can be known _kThe TPC initial power of PUCCH, definition minimum emissive power ε _k, ε _k=P _{PUCCH, k}

Step 6.1 is judged and is adjusted the result

Whether satisfy the minimum emissive power restriction.If satisfy, promptly

Then go to step 7; Otherwise, go to step 6.2.

Step 6.2 is its minimum emissive power with the power setting of not satisfying the CC of minimum emissive power restriction, forwards step 4 to.

Step 7, according to

Distribute transmitting power.

The throughput ratio that emulation shown in Figure 2 is adjusted the algorithm after method and the present invention's simplification for CC equivalent.Method 1 among the figure is adjusted method for CC equivalent, and promptly when the TPC of UE initial results did not satisfy maximum transmission power, all CC distributed the adjustment amount that equates.Method 2 is the algorithm that the present invention simplifies, adopt the classification of two class methods and etc. the side-play amount adjustment.Suppose that the power before TPC is the maximum power that UE allows, the power behind the TPC compares with it.The minimum power limits value of supposing CC is a fixed constant.The distribution of transmitting power all be theoretical at random.

As can be seen from the figure, under the situation of different CC numbers, the average throughput of method 2 always is higher than method 1, i.e. the performance loss that causes of method 1 is bigger.

Claims (4)

1. uplink power adjustment method based on the LTE-Advanced system is characterized in that comprising:

Step 1 calculates the PUCCH of subcarrier and the TPC initial power P of PUSCH _{PUCCH, k}And P _{PUSCH, k}

Step 2 judges whether the TPC initial power satisfies the maximum transmit power limit condition, if satisfy, promptly

Then jump directly to step 7; Otherwise enter step 3; Wherein k is the label of subcarrier, and K is the number of subcarrier,

Be the TPC initial power of subcarrier k, P _MAXMaximum transmission power for UE;

Step 3, the priority of adjustment is determined in classification to subcarrier;

Step 4, calculate the power that needs adjustment:

Step 5 is adjusted side-play amount according to the classification results distribution of step 3, obtains adjusted power

And be made as the priority of adjusted subcarrier minimum; Δ wherein _kFor subcarrier k is CC _kSide-play amount, Δ _kPower/M that=needs are adjusted, M are limit priority set sub-carriers number;

Step 6, definition minimum emissive power ε _k, ε _k=P _{PUCCH, k}, judge adjusted power

Whether satisfy the minimum emissive power restriction, if satisfy, promptly

Then go to step 7; Otherwise, be its minimum emissive power with the power setting of not satisfying the subcarrier of minimum emissive power restriction, go to step 4.

Step 7,

Be transmitting power.

2. according to the described a kind of uplink power adjustment method based on the LTE-Advanced system of claim 1, it is characterized in that: the TPC initial power of the PUCCH of step 1 sub-carriers and PUSCH calculates according to following formula:

P _PUCCH，k＝P _{0_PUCCH}(k)+PL(k)+h(·)+Δ _{F_PUCCH}(·)+g(k)

P _PUSCH，k＝10·log ₁₀M _PUSCH(k)+P _{0_PUSCH}(k)+α(k)·PL(k)+Δ _TF(k)+f(k)

Wherein, k is the label of subcarrier, M _PUSCHBe the resource block number of PUSCH, P _{0_PUSCH}Be the parameter that the sub-district is specific or UE is specific, α is the specific path compensation coefficient in sub-district, and PL is the path fading loss value of down-run survey, Δ _TFBe the parameter at certain specific modulation coded system of rrc layer appointment, f is that h is the PUCCH format parameter, Δ by the relevant function of transmitting power control closed loop correction factor specific with the sub-district of high level control _{F_PUCCH}Be the rrc layer designated parameters, g is the transmitting power control closed loop correction factor relevant function specific with the sub-district by high level control.

3. according to the described a kind of uplink power adjustment method based on the LTE-Advanced system of claim 1, it is characterized in that: the described subcarrier classification criterion of step 3 nicety of grading is divided into two class methods and N class method;

Two class methods according to TPC initial power and TPC before the positive and negative of numerical difference between of transmitting power subcarrier is divided into two classes, selecting the non-positive subcarrier of numerical value be the object of preferential adjustment;

N class method according to TPC initial power and TPC before the magnitude classification of difference of transmitting power, from the minus tolerance to the principal-employment, subcarrier is divided into the N level, wherein N is smaller or equal to the number of subcarrier, progression N is many more, it is meticulous more to classify; Numerical difference between is more little, and the category label that is included into is more little, and the priority of adjustment is high more.

4. according to the described a kind of uplink power adjustment method of claim 1, it is characterized in that: side-play amount methods such as the method for adjustment employing of the described side-play amount of step 5, the adjustment side-play amount that promptly subcarrier allocation of same classification is identical based on the LTE-Advanced system.