HK1182265A - A wireless transmit/receive unit (wtru), method and integrated circuit - Google Patents

Abstract

A wireless transmit/receive unit (WTRU)，a method and an integrated circuit are provided. the WTRU comprising: means for deriving a first maximum power reduction MPR and a second MPR; wherein the first and second MPRs are derived at least from a modulation type for an uplink transmission of the WTRU; means for selecting the first or second MPR; means for modifying a maximum output power of the WTRU in response to the selected first or second MPR; and means for transmitting the uplink transmission at an output power not exceeding the modified maximum output power.

Description

Wireless transmit/receive unit (WTRU), method and integrated circuit

The present application is a divisional application of the chinese invention patent application having an application number of 200880012833.2, a date of application of 2008/19/4, entitled "apparatus and method for calculating maximum power attenuation of UMTS signal".

Technical Field

The present application relates to wireless communications.

Background

In practical amplifier circuits, such as those used in the Universal Mobile Telecommunications System (UMTS) Wireless Transmit Receive Unit (WTRU) transmit chain, the induced spectral regrowth is due to non-linear amplifier characteristics. The term spectral regrowth describes an increase in out-of-band signal energy at the output of the power amplifier. Spectral regrowth resulting from the non-linear amplifier effect is generated primarily in the channel adjacent to the desired transmit channel. For UMTS, the requirements for the power amplifier are defined by an Adjacent Channel Leakage Ratio (ACLR) of +/-5MHz at the desired channel. The following is the amplifier voltage gain characteristic:

v_o(t)＝g₁·v_i(t)+g₂·v_i(t)²+g₃·v_i(t)³+...+g_n·v_i(t)ⁿequation (1)

Wherein, g₁·v_i(t) is the linear gain of the amplifier, the remainder (i.e., g)₂·v_i(t)²+g₃·v_i(t)³+...+g_n·v_i(t)ⁿ) Representing the nonlinear gain. If the signal carries modulated third generation partnership project (3 GPP) Radio Frequency (RF), a non-linear term may be generated as a result of intermodulation distortion, which may generate an in-band distortion term that may cause an increase in Error Vector Magnitude (EVM) and an out-of-band distortion that may cause an increase in ACLR. Both of which cause a degradation in the modulation quality.

Multicode signals such as in UMTS release 5 and release 6 achieve an increase in peak-to-average power, which results in greater dynamic signal variations. These increased signal changes require greater amplifier linearization, which results in greater power consumption. Recent results indicate that directly transmitting dB for dB (i.e., the ratio of the peak power to the average power of the signal, also known as the peak-to-average ratio (PAR)) is not effective for amplifier power reduction (reduction). Analysis of the spectral regrowth of the amplifier shows that the 3 rd order nonlinear gain term ("cubic gain") is the main cause of the ACLR increase. The total energy of the cubic term depends on the statistical distribution of the input signal.

With the introduction of High Speed Uplink Packet Access (HSUPA), a new method for eliminating amplifier power attenuation, called Cubic Metric (CM), was introduced in release 6. CM is based on the cubic gain portion of the amplifier. CM describes the ratio of the cubic portion to the 12.2kbps speech interference signal in the observed signal. The CM is applicable to both High Speed Downlink Packet Access (HSDPA) and HSUPA uplink signals. Statistical analysis shows that the power de-rating estimated from CM shows a significantly smaller error distribution compared to the power de-rating according to 99.9% PAR, where the error distribution refers to the difference between the actual power de-rating and the estimated power de-rating.

The 3GPP specifies a Maximum Power Reduction (MPR) test, which indicates that the maximum transmit power of the WTRU is greater than or equal to a nominal (nominal) maximum transmit power, but less than the total amount of so-called "maximum MPR", where maximum MPR is a function of the CM of the transmitted signal. For a given power amplifier, the manufacturer may decide that the device needs to limit its maximum power to some amount, referred to herein as "minimum MPR", which is less than the maximum MPR, but is compatible with 3GPP ACLR. While "minimum MPR" may be defined as a function of CM, it may alternatively be defined as a function of a certain percentage of PAR. Limiting the maximum power using minimum MPR instead of maximum MPR enables the WTRU to transmit at a larger maximum power, thus making the WTRU manufacturer with minimum MPR more competitive. It is also possible that a WTRU design may include both the maximum MPR and the minimum MPR and select between them.

Regardless of the selection of the maximum MPR or the minimum MPR, the key issue is that the WTRU must know the values of CM and/or PAR to calculate the selected MPR, and eventually use these values to actually set the transmit power, if needed, (i.e., if the WTRU is operating near maximum power). Any multi-code signal (characterized by the physical channel being transmitted, its channelization code, and a weight called the beta term) has its specific CM and PAR.

In UMTS, the signal, and both CM and PAR, may vary in Transmission Time Intervals (TTI) of every 2 or 10 milliseconds. It can be seen that for UMTS release 6 there are over twenty thousand combinations of physical channel parameters and quantized beta terms, each of which is referred to herein as a possible signal. The large number of possible signals makes it impractical to form a strictly one-to-one predetermined look-up table of CM or PAR as a function of signal characteristics for real-time applications; particularly in small low power handheld devices operating at UMTS data rates. Knowing that it is not possible for the WTRU to simply find the CM or PAR, it needs to be measured or estimated from the characteristic parameters of the signal within some tolerable error.

It is known to measure CM or PAR from the actual signal. An important drawback is that the signal must first be generated to make the measurement. Since the transmit power may eventually be set as a function of CM and/or PAR, setting the power by measurement will require the generation of a signal or a portion of a signal for at least a period of time before transmission. While this is theoretically possible, the time delay requirements and practical memory limitations of UMTS make this approach impractical.

A variation of the above method is to generate and start transmitting signals at power levels calculated from "guesses" of CM or PAR and adjust the transmit power to the second power level in the entire time slot remaining in the subsequent TTI. The combination of the first and second power levels is calculated such that the average power level is close to the power level selected for the CM or PAR known before the TTI start.

In UMTS there are 15 slots in a 10 ms TTI, but only three slots in a 2 ms TTI. Assuming that, for example, measurements of CM or PAR require some fraction of one slot of a TTI, e.g., 10 ms, to be completed, the initial power level will be set for only the first slot, while the remaining 14 slots use the second value. For a 2 ms TTI, the initial power level will be set to use the first slot, which is one third of the TTI, while the remaining two thirds of the TTI will use the second value. Obviously, this approach is not consistent, especially in the case of a 2 ms TTI. Therefore, there is a need for a method for determining CM or PAR to determine maximum MPR and/or minimum MPR, and final transmit power, before starting to transmit a signal.

Disclosure of Invention

A method and apparatus for controlling transmission power using an estimated value of CM or PAR by estimation are provided. This method may be applied to determine a maximum power reduction value (MPR) or a minimum MPR for calculating a maximum MPR by estimating CM or PAR from signal parameters, as opposed to directly measuring CM or PAR. The method of estimating CM or PAR is applicable to any multicode signal.

The invention provides a wireless transmit/receive unit (WTRU), comprising: means for obtaining a first maximum power reduction, MPR, and a second MPR; wherein the first and second MPRs are obtained from at least a modulation type of an uplink transmission of the WTRU; means for selecting the first or second MPR; means for modifying a maximum output power of the WTRU in response to the selected first or second MPR; and means for transmitting the uplink transmission at an output power that does not exceed the modified maximum output power.

The invention also provides a method, comprising: obtaining, by a wireless transmit/receive unit (WTRU), a first Maximum Power Reduction (MPR) and a second MPR; wherein the first and second MPRs are obtained from at least a modulation type of an uplink transmission of the WTRU; selecting, by the WTRU, the first or second MPR; modifying, by the WTRU, a maximum output power of the WTRU in response to the selected first or second MPR; and transmitting the uplink transmission at an output power not exceeding the modified maximum output power.

The present invention also provides a wireless transmit/receive unit (WTRU) comprising: an antenna; means for determining a first Maximum Power Reduction (MPR) and a second MPR, the means for determining the first Maximum Power Reduction (MPR) and the second MPR operatively coupled to the antenna; means for selecting an MPR based on the determined first and second MPRs; and means for reducing the transmit power level based on the selected MPR.

The invention also provides a method, comprising: determining, by a wireless transmit/receive unit (WTRU), a first Maximum Power Reduction (MPR) and a second MPR; selecting, by the WTRU, an MPR based on the determined first and second MPRs; and reducing, by the WTRU, a transmit power level based on the selected MPR.

The invention also provides an integrated circuit comprising: a circuit configured to determine a first Maximum Power Reduction (MPR) and a second MPR; wherein the circuitry is further configured to select the MPR based on the determined first and second MPRs; and wherein the circuitry is further configured to control a reduction in transmit power of a wireless transmit/receive unit (WTRU) based on the selected MPR.

Drawings

A more detailed understanding of the present invention may be derived from the following description of the preferred embodiments, which is given by way of example and which is to be read in connection with the accompanying drawings, wherein:

figure 1 is a functional block diagram of a Wireless Transmit Receive Unit (WTRU) in accordance with the present invention;

FIG. 2 is a block diagram of a simplified version of an offline processor;

FIG. 3 is a detailed flow chart of an offline initial configuration process;

figure 4 is a block diagram of a WTRU in accordance with one embodiment;

fig. 5A and 5B are two diagrams for the model of equation 5 and the model of equation 6, respectively, showing the distribution of the maximum MPR estimation error;

FIGS. 6A and 6B are two graphs for the model of equation 5 and the model of equation 6, respectively, showing the distribution of CM estimation error;

FIGS. 7A and 7B are two graphs for the model of equation 5 and the model of equation 6, respectively, showing the distribution of PAR estimation errors; and

fig. 8 is a flow chart of a method of setting transmit power.

Detailed Description

The term "wireless transmit/receive unit (WTRU)" as referred to hereinafter includes, but is not limited to, a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a Personal Digital Assistant (PDA), a computer, or any other type of user equipment capable of operating in a wireless environment.

The term "base station" as referred to hereinafter includes, but is not limited to, a node-B, a site controller, an Access Point (AP), or any other type of interfacing device capable of operating in a wireless environment.

Fig. 1 is a block diagram of a WTRU 120 configured to perform the methods disclosed below. In addition to the components contained within a typical WTRU, the WTRU 120 includes a processor 125 configured to perform the disclosed methods; a receiver 126 in communication with the processor 125; a transmitter 127 in communication with the processor 125; an antenna 128 in communication with the receiver 126 and the transmitter 127 to enable the transmission and reception of wireless data. The WTRU communicates wirelessly with the base station 110.

A method for estimating the transmission CM and/or PAR of a signal according to the configuration parameter of the signal and calculating the MPR using the estimated value will be described below. The configuration parameters include the number and type of physical channels and the configuration situation. The configuration case may be defined as a combination of channelization codes and channel weights (called beta), preferably for in-phase (I) and quadrature channel (Q) part codes. The channel weights (for a given service and data rate), other parameters, the so-called "configuration" below, and all combinations of the above are determined according to the specifications defined by 3 GPP.

A signal may be defined as a combination of a physical channel and a beta term. Each possible signal must be in at least one configuration case. The definition may be extensible. For example, a subset or limited range of some or all of the beta terms for one or more physical channels including the configuration case may be included. The identification (identification) of the smallest subset of configuration cases, which specify the minimum acceptable CM and/or PAR estimation errors, which are in turn used for the MPR estimation errors, is subjective.

An example of a set of 11 configuration cases is shown in table 1. These configuration cases are limited to allowing up to one DPDCH. Those skilled in the art will appreciate that the configuration is not so limited. However, this is likely to be undesirable. Empirical results indicate that an acceptably small estimation error, in particular the maximum MPR estimation error, is less than or equal to 1.5 dB. Table 1 shows that the configuration case is generally defined by three main features: 1) maximum number of DPDCHs (Nmax DPDCHs); 2) whether High Speed (HS) is enabled; and 3) the number of E-DPDCH and the Spreading Factor (SF) (E-DPDCH code @ SF). An alternative mapping is given in table 2. Table 2 shows that some of the cases originally defined in table 1 are divided into a plurality of cases, so that less errors than the mapping of table 1 can be generated. In particular, it means that the maximum MPR estimation error is less than or equal to 1.0 dB.

Referring back to table 1, the column of HS Chan codes relates to the specific "SF and orthogonal variable length (OV) SF codes" used for HS-DPCCH. Note that the SF is typically 256, and for OVSF, one of two codes (33 and 64) is used. When the third column (i.e., HS) shows no ("N") HS, this column is denoted "unavailable" (N/A).

The E-DPDCH 1,3I or Q column indicates that in this section, I or Q, E-DPDCH channels #1 and #3 are displayed, which are used according to the situation of the column.

The E-DPDCH 1,3Chan code column, if any, relates to the SF and OVSF codes used for E-DPDCHs related to channels #1 and # 3. For example, configuration case 6 has two E-DPDCHs, labeled #1 and #3, the remainder of the column being either none (unavailable) or one (default to "# 1"). Most configuration cases have only one E-DPDCH.

The E-DPDCH 2,4Chan code column is similar to above for the case with two or more E-DPDCHs.

The I and Q columns indicate the beta terms in the I and Q sections. In configuration case 6, β_edInvolving E-DPDCH channels #1 and #2, and beta_ed3/4Relating to E-DPDCH channels #3 and # 4.

TABLE 1

TABLE 2

Configuration case 0 in tables 1 and 2 is a known normal case requiring zero maximum MPR. For this configuration case, the calculation method for all other configuration cases is not used, but the maximum MPR and/or the minimum MPR are simply set to zero.

Referring to fig. 2, a simple version of an offline process 200 is shown. As will be described in greater detail below in conjunction with fig. 3, the process 200 ultimately calculates and stores parameters for the WTRU to produce maximum MPR and/or minimum MPR values. In UMTS every combination of physical channels and parameters and quantization values beta is a possible signal. The quantization value is based on the configuration of the signal. First, all possible signals are mapped to a set of configuration cases (210). By using the information given in the two rightmost columns of table 1 (I and Q), quantized values can be generated for all possible signals (220). The CM and/or PAR for all possible signals are measured by transmitter simulation (230). The measurement of CM and PAR will be described in more detail below.

The pre-calculated term a is preferably determined 240 by using the output of the transmitter simulation 230. A set of alpha terms for CM and/or a set of alpha terms for PAR, calculated according to equation 7 below, is preferably determined for each configuration case defined above.

For each configuration case, the transmitter simulation 230 measures CM and PAR for all possible signals, (a mathematical derivation of the estimation of CM and/or PAR will be detailed below), where signals are defined as all possible combinations of quantized β terms 220 in 3 GPP. The pre-calculated alpha term can be determined for a particular configuration case using a least squares fit method, from all possible signals of the configuration case, or from a typical subset thereof. The calculated alpha term, configuration and calculated adjustment factor are calculated (240). These values are then written into the WTRU 400 by firmware, software, or hardware.

Fig. 3 is a flow chart of an offline initial configuration process (300). The process 300 calculates the alpha term for both CM and PAR simultaneously and determines the adjustment factor for the configuration case. These values are stored in the WTRU (400) for estimating CM and PAR for a given signal.

Referring to FIG. 3, a detailed version of an offline process 300 is shown. First, a configuration case is defined according to characteristics of a physical channel at 310. For example, as shown in configuration case 9 in table 1, DPCCH, one DPDCH (largest one DPDCH), HS-DPCCH (Δ @)_ACKAnd Δ_CQIAre set equal; positive Acknowledgement (ACK) and Channel Quality Indication (CQI)) are always sent, E-DPCCH and 2SF @ =2 (two E-DPDCHs at SF equal to 2).

The information in the two right-most columns of table 1 (I and Q) is used to determine the required individual, square and intra-component cross β terms. From the notation of equation 5 (to be described later), { β }_I1 β_I2 β_I3}={β_d β_ec β_edAnd { beta ]_Q1 β_Q2 β_Q3}={β_c β_hs β_ec(designation of a specific number is arbitrary). Sixteen such entries are defined in table 3: beta is a_ec，β_ed，β_d，β_c，β_hs，β_ec ²，β_ed ²，β_d ²，β_c ²，β_hs ²，β_ecβ_ed，β_ecβ_d，β_edβ_d，β_cβ_hs，β_cβ_edAnd beta_hsβ_ed。

All possible signals for the configuration case (i.e., all combinations of quantized beta terms for the channel) are then determined (320). Per 3GPP, there is beta_cAnd beta_dThirty implicit combinations of numerical pairs of (A)_hs=β_hs/β_cExplicit nine values of (A)_ec=β_ec/β_cNine values of (A) and_ed=β_ed/β_cor a total of 72900 possible signal combinations for each configuration case. The 72900 combinations are not listed here.

Transmitter simulations were used to measure CM and measure 99% PAR for all 72900 possible signals for each configuration case (330). The 145800 values measured are not listed here.

Using the 72900 possible signals for each configuration case and their linear CM and linear PAR measurements, sixteen pre-computed α values for estimating CM and sixteen pre-computed α values for estimating PAR are computed using equation 7 (340). The sign terms are given in equations 8 to 7; the numerical value of the alpha term is given in table 3. Although only a small subset of 72900 combinations may be used, assuming that matrix X with 72900 rows is needed in the next step, the entire complete set of 72900 combinations is used for calculating Table 3 for one configuration case.

TABLE 3

Function of the beta term	αCM	αPAR
			βec	-1.53154	-0.0333305
βed	-1.04303	+1.97253
			βd	-1.88422	-0.691914
βc	-1.10666	-1.24791
			βhs	-0.851261	-0.642072
βec 2	+2.7545	+2.3413
			βed 2	+3.39477	+1.35334
βd 2	+2.85157	+2.61758
			βc 2	+2.47229	+2.86022
βhs 2	+2.37892	+2.63543
			βecβed	+2.33816	+1.72716
βecβd	+2.18533	+1.27585
			βedβd	+2.95673	+2.75154
β.cβhs	+1.75287	+1.80679
			β.cβed	+2.05286	+3.06353
βhsβed	+1.59968	+2.07734

For each possible signal, the linear CM and linear PAR are estimated using the models described by equations 5 and 6 (described below) (350). The calculation in matrix form is given in equation 12. The matrix X is the numerator of equation 5 and includes a normalization function for a single β term. The matrix Y is the linear CM multiplied by the linear PAR measurement multiplied by the denominator of equation 5; the model of equation 6 uses a similar form.

The estimation error for both CM and PAR is preferably calculated using equation 13 (360). For further description, the distribution of the CM estimation error (in dB) is given in fig. 6A and 6B. The distribution in the form of the PAR error dB is given in fig. 7A and 7B. Fig. 6A and 7A represent the model described by equation 5, and fig. 6B and 7B represent the model described by equation 6.

The required adjustment factor is then determined (370). It can be seen by inspection that for the model of equation 5, the adjustment factor for maximum MPR, the maximum magnitude positive error in fig. 6A is about 0.54dB or 1/0.883. If the minimum MPR is the desired result, the adjustment factor using CM for the minimum MPR, the maximum magnitude negative error in FIG. 6A is about-0.71 dB. The adjustment factor using PAR for minimum MPR, the maximum magnitude negative error in fig. 7A is about-0.41 dB. As can be seen from FIGS. 6B and 7B, the corresponding values for the model of equation 6 are-0.54 dB, -0.80dB, and-0.57 dB.

The distribution of the maximum MPR error is determined (380) by using adjustment factors that are both consistent to 0.54dB, as calculated above.

Referring to fig. 5A and 5B, the distribution of the maximum MPR error shows that for both models, the maximum MPR error is 1.5dB, and both models can theoretically be used if it is considered to be small enough (which is the case in this example).

As a second criterion, it should be noted that, as shown in fig. 5A and 5B, the frequency of occurrence of the maximum error of the model of equation 5, i.e., 9/72900, is lower than that of the model of equation 6, i.e., 406/72900. Thus, the model of equation 5 is selected and the alpha value and adjustment factor (390) are configured in the WTRU (400). Alternatively, the model estimate CM of equation 6 requires less multiplication, and the model may be selected if this is a significant factor.

The derivation of the estimated CM and/or PAR will now be described. After the channel weights have been used, but before the root raised cosine and other filters are used, the PAR of the uplink signal is determined according to equation 2.

Equation (2)

Wherein;

β_Iis the channel weight for the physical channel in section I;

β_Qis the channel weight for the physical channel in the Q section;

N_Iis the number of physical channels in section I; and

N_Iis the number of physical channels in the Q section.

According to one embodiment, for a given configuration scenario, the CM is preferably chosen to be_linear(linear instead of CM in dB form, and without 0.5dB quantization by 3GPP method) as a pre-filter PAR with equation 2_linearThe function of interest, as shown in equation 3:

equation (3)

Wherein;

γ_jis the actual weighting factor for each physical channel;

n is an integer defining an indicative number of sums;

N_Orderis the order of any polynomial; and

is a normalization function which makes gamma_jThe value of (b) is independent of any proportion of β.

The same function as in equation 3 can also be used to estimate the PAR at the filter output_linearIn which only the value of the y term is associated with CM_linearThe difference in (c). For any possible signal for a given configuration case, CM is estimated using equation 3_linearAnd PAR_linearAn error will typically be generated between the estimated value and the measured value, which is called an estimation error.

Although N is_OrderCan be selected as any positive integerBut in one embodiment it is, for example, N_OrderAnd (2). Empirical results show that by using N_Order=2, the range of estimation errors for all possible signals is an acceptable small range for determining both the maximum MPR and the minimum MPR. Thus, N is_OrderSelecting greater than 2 creates additional complexity without significant performance improvement. Therefore, when N is equal to_OrderWhen set to 2, equation 3 reduces to that shown in equation 4:

equation (4)

Extending equation 4 yields equation 5.

Equation (5)

CM described by this equation_linearSubstantially equal to the weighted form of the inner product of a single square weighting (weighted by the square root term), the intra-component cross β term, and the not-yet-known α term. The formula is also applicable to PAR_lnearOnly the value of the alpha term is different.

The alternative model described in equation 5 is represented in equation 6. The model of equation 6 removes the single β term and the associated normalization function (the last term in the numerator of equation 5). Empirical results show that for some configuration scenarios, the model will yield less estimation error than the model of equation 5.

Equation (6)

For a given configuration case, the value of the α term may be determined from: 1)CM using transmitter emulation (230) to measure all or a small set of typical possible signals_linearAnd/or PAR_linea(ii) a And 2) given in equation 7 in the form of a matrix using a known least squares fitting method:

α＝(X^TX)^-1X^Ty equation (7)

Wherein;

x is a matrix (known as a design or Vandermode matrix), one row per signal, where each element in a row is a digital value of the squared, single weighted or intra-component cross-over β terms. This is achieved by converting the symbol β in equation 5 or equation 6_IAnd beta_QDetermined instead as the beta term for a particular channel; for the case of two or four E-DPDCH each single and squared beta_edShould occupy only one row of X, rather than two or four; and is

Y is a column vector having one element per signal, where each portion is the measured CM, respectively_linearOr PAR_linear. The signal weighting factors in the denominator of equation 5 or equation 6 are multiplied, assuming that the alpha term for estimating CM or the alpha term for estimating PAR is to be calculated. Alternatively, assuming that the alpha terms for estimating CM and PAR are to be calculated simultaneously, Y may be a matrix with two such columns: one for CM_lnearAnd the other for PAR_linear。

The sign term (rather than its numerical value) used in equation (7) to calculate the α term for this example is provided below:

equation (8)

Equation (9)

Equation (10)

Equation (11)

Equation (12)

Equation (13)

The reduced set of possible signals referenced by the above example relates to the case where the number of signals required to reliably calculate the alpha term may be orders of magnitude less than the number of all possible signals. However, using equations 12 and 13, the matrix X with all possible signals is used to calculate the estimation error. By limiting the number of signals in X used to calculate the alpha term, no significant savings are produced in the offline processor 200.

As specified in equations 5 and 6, the weighting factors, the digital powers (the denominators of equations 5 and 6), and the root mean square magnitude of each signal (the root mean square term in the numerator of equation 5) used to construct matrices Y and X, respectively, may be the same or substantially the same for all signals in a particular implementation. In this case, there may be no need to perform calculations for each signal. Instead, the two weighting factors may each be a constant that is common to all signals.

If the ratio of the digital beta term in the transmitter simulation used to measure CM and/or PAR and then calculate the alpha term is equal to the ratio of the digital beta term in the WTRU, the weighting factors may also be removed from equations 5 and 6 and effectively incorporated into the alpha term.

Using the procedures of fig. 2 and 3, the alpha terms for all defined configuration cases, the adjustment factors for each configuration case, and the model that can minimize the maximum MPR or the minimum MPR have been calculated for both models described in equations 5 and 6. The models of the minimum maximum MPR and the minimum MPR are calculated according to:

for the maximum MPR case, there are three alternatives to determine a model that minimizes the maximum MPR estimation error.

The first alternative is the CM estimated from equation 5 or 6_linearShould be adjusted so that the adjusted estimated CM is not greater than the value obtained from the actual measurement of CM. The adjustment factor should be the maximum magnitude positive error for the particular configuration case; this factor should be subtracted from the actual estimate. The purpose of such an adjustment error is to prevent overestimation of CM for any signal.

The second alternative is the CM estimated from equation 5 or 6_linearShould be adjusted such that the maximum MPR determined from the adjusted estimated CM is not greater than the maximum MPR obtained from the actual CM measurement. The purpose of adjusting the error in this way is to prevent the maximum MPR from being estimated too high for any signal. The method of determining the adjustment factor is as follows:

1) for each signal in the configuration, an estimated MPR (MPR _ estimated) is determined using the estimated CM, and an actual MPR (MPR _ true) is determined from the known simulated actual CM.

2) The MPR error (MPR _ error) is calculated according to equation 14:

MPR _ error _ true-MPR _ affected equation (14)

3) From the signal with MPR error less than 0, the original adjustment factor (adjustment _ factor _ raw) is selected according to equation 15:

adjustment _ factor _ raw ═ max (CM _ estimated-ceil (CM _ true,0.5)); equation (15)

Where ceil (·,0.5) means rounding up to the nearest 0.5.

4) The final adjustment value is the value of equation 15 plus a small amount, ε, to ensure that the signal in equation 15 with the largest CM _ estimated is not rounded up to the next 0.5dB after the adjustment factor is used. In other words, the adjustment factor (adjustment _ factor) is calculated using equation 16, where the largest is selected from the signals where the MPR error is less than zero.

adjustment _ factor max (CM _ estimated-ceil (CM _ true,0.5)) + ε equation (16)

A third alternative is to use a smaller magnitude adjustment factor than used in the other alternatives, with the selected amount being a design compromise (e.g., to prevent overestimating CM only for certain signals of the configuration case).

For the case where the minimum MPR is calculated to determine the model that minimizes the minimum MPR estimation error, the estimated CM or PAR should be adjusted so that the adjusted CM or PAR is not less than the actual measurement of the CM or PAR. The adjusted factor should be a negative CM or PAR estimation error of maximum magnitude for the particular configuration case; which should be subtracted from the actual estimate. The purpose of using the adjustment factor in this way is to prevent underestimating CM or PAR for any signal. Alternatively, a smaller magnitude negative adjustment factor may be used, with the selected amount as a design compromise (e.g., to prevent underestimating CM only for certain signals of the configuration case).

For each configuration case, after the adjustment factors are used in either method, it must be evaluated whether the error is small enough for both models. The distribution of measurement errors for a particular configuration is given in fig. 5A, 5B, 6A, 6B, 7A and 7B. FIGS. 5A,6A and 7A show the model described in equation 5; fig. 5B,6B, and 7B represent the model described in equation 6. Fig. 5A and 5B show the distribution of the maximum MPR estimation error for a specific case. In fig. 5A and 5B, the distribution is highly quantized due to the ceiling (ceil) operation in the maximum MPR calculation.

FIGS. 6A and 6B show the strength of the CM estimation error; fig. 6A has a somewhat narrower intensity than fig. 6B. The distributions in fig. 6A and 6B and the distributions in fig. 7A and 7B are substantially continuous. Fig. 7A and 7B show the error strength of the estimated PAR. To calculate the maximum MPR, the maximum MPR error should be within the desired limits. Alternatively, the difference between the extreme positive and negative CM measurement errors within the desired limits may be taken as a criterion. However, it is preferable to use the largest maximum MPR error. To use CM or PAR to calculate the minimum MPR, the difference between the limit positive and negative measurement errors should be within the required range.

For maximum MPR, the result of using the adjustment factor according to the first alternative is that no signal has an over-estimated MPR, but some signals have an under-estimated MPR. The result of using an adjustment factor according to the second alternative is that no signal has a too high estimated CM, but some signals have a too low estimated CM. In particular, the signal with the largest positive CM error will have the correctly estimated CM, the signal with the largest magnitude negative CM error will have the underestimated CM due to the difference between the largest magnitude positive and negative CM errors, and the other signals will have the underestimated CM due to some smaller amount.

For minimum MPR, the result of using an adjustment factor is that no signal will have an underestimated CM or PAR; while some signals have over-estimated CM or PAR. In particular, the signal with the largest positive CM or PAR error will have a correctly estimated CM or PAR; a signal with a maximum magnitude positive CM or PAR error will have an overestimated CM or PAR due to the difference between the maximum magnitude positive and negative CM errors.

There are two possible problems with estimation errors: first, the calculated minimum MPR may exceed the calculated maximum MPR due to intentional underestimation and overestimation of CM and PAR. In this case, the WTRU may not be able to select a value for MPR that ensures compliance with both MPR and ACLR requirements of, for example, the 3GPP standard. Secondly, the greater the difference between the positive and negative estimation errors of the maximum amplitude, the greater the difference between the minimum MPR obtained according to the method and the minimum MPR assumed to be obtained by the measurement, thus reducing the maximum transmit power that can be achieved.

Two possible measures to the above problem are: 1) the above trade-off may be used by choosing alternative adjustment factors, such that for some possibly smaller signal sets, the calculated MPR is not applicable; and 2) a particular configuration case may be divided into two or more configuration cases, resulting in less estimation error. For example, if the analysis shows that the largest β terms produce the largest estimation error for a particular physical channel, then these β terms are used to establish a separate configuration case.

Once a set of configuration cases has been defined and the alpha terms and adjustment factors for all configuration cases have been calculated, they are preferably stored in the table of the WTRU.

Referring to fig. 4, a WTRU 400 is shown. Before transmission starts every TTI, an appropriate configuration case is selected to configure the data provided by the Medium Access Control (MAC) layer of the transport block. To define the set of configuration cases given in table 1, the selection is made according to the combination of physical channels used to transmit the transport blocks, and possibly the E-DPDCH spreading factor.

Regardless of whether the MPR calculation device (430) calculates the maximum MPR, the minimum MPR, or both, and if the device calculates the minimum MPR using PAR, CM is estimated according to equation 17_linearEquation 17 is a simplified form of equations 5 and 6:

equation (17)

Where N and D are the numerator and denominator of equation 5 or equation 6, respectively, and the CM α terms of the above-identified configuration case are used. Estimating PAR using equation 11_linearBut will CM_linearReplacement to PAR_linearAnd use the formulationThe PAR α term for the case. Then, CM is added_linearAnd/or PAR_linearConversion to dB form.

If the MPR computing device (430) computes the maximum MPR, the selected adjustment factor (in dB) for computing the maximum MPR is subtracted from the estimate of CM in dB. This gives the CM value used to calculate the maximum MPR.

If the MPR calculation device (430) calculates the minimum MPR using the CM, the selected adjustment factor (in dB) for calculating the minimum MPR is subtracted from the estimate of the CM in dB. This results in the minimum MPR being calculated using the CM value.

If the MPR calculation apparatus (430) calculates the minimum MPR using PAR, an adjustment factor (dB) selected for calculating the minimum MPR using PAR is subtracted from the estimate of PAR in dB, and the result is used to calculate the minimum MPR.

If the MPR calculation device (430) calculates the maximum MPR, the maximum MPR is preferably calculated according to 3 GPP. If the MPR calculation device calculates the minimum MPR, the minimum MPR is preferably calculated according to the specification of the power amplifier.

If the device calculates the maximum MPR or the minimum MPR, but not both, the calculated maximum MPR or minimum MPR is output as an MPR value used to set the transmission power. The device that calculates the maximum MPR and the minimum MPR at the same time may select some intermediate value as the MPR value for setting the transmit power and remain in accordance with the standard and manufacturer's recommendations.

It is not necessary to fully estimate the value of CM in practice, but it is only necessary to detect whether the estimated CM value is above or below one or more thresholds. One possible threshold test may be provided by slightly modifying equation 17, such as equation 18, which has the advantage of avoiding the partitioning operation in equation 17.

Equation (18)

Wherein, CM_linearTIs CM_linearA specific threshold value of;the operator is a threshold test, indicating CM if the inequality is true_linearGreater than CM_linearT。

Table 4 is derived from table 6.1A of 3GPP TS 25.101, which shows an efficient algorithm given in the form of language C, which sets the value of max _ MPR _ dB and the threshold. The linearly equivalent value of the adjustment factor is selected for calculating the maximum MPR.

TABLE 4

Numbering	CM_linear_T	MPR_dB
			0	10^(1.0/10)=1.258925	Is not used
1	10^(1.5/10)=1.412538	0.5
			2	10^(2.0/10)=1.584893	1.0
3	10^(2.5/10)=1.778279	1.5
			4	10^(3.0/10)=1.995262	2.0
5	Is not used	2.5

The dedicated device algorithm for calculating the minimum MPR is similar to that for calculating the maximum MPR, and depending on the specific number, there is likely to be only one threshold for CM and/or PAR, and a similar algorithm may be used for the calculation.

Returning to fig. 4, fig. 4 is a WTRU 400 configured for wireless communication, which receives and processes digital user data and control data by a scaling circuit 450 to digitally scale the data to set its relative transmit power. Digital user data may be encoded into a channel such as a Dedicated Physical Data Channel (DPDCH) or an enhanced DPDCH (E-DPDCH). The control data may be encoded into a channel such as a Dedicated Physical Control Channel (DPCCH), a high speed DPCCH (HS-DPCCH), or an enhanced DPCCH (E-DPCCH). The scaling circuit 450 operates in these respective channels.

The scaled data is filtered by filter device 460, converted to an analog signal by analog-to-digital converter (DAC) 470, and transmitted by radio transmitter 480 through antenna (Tx) 490. The WTRU's transmitter has an adjustable (i.e., power controllable) overall transmit power, as well as a scalable single channel input, as represented in figure 4 by an analog gain term and a digital gain term, respectively. Other forms of controllable transmission device may also be used.

The transmit power of the individual channels and the overall transmit power are set by the transmit power control unit 440 according to the procedure defined in 3 GPP. The nominal maximum transmit power is determined by the WTRU power level or the network. The maximum transmit power of the WTRU power class is defined in 3 GPP. The WTRU may automatically limit its maximum transmit power using a maximum MPR, which is a value within a range defined by 3GPP, or a smaller device-specific minimum MPR.

The transmission power control unit 440 sets transmission power using a plurality of parameters. One of these parameters is MPR. To calculate MPR, the configuration case is first defined according to the offline configuration parameters, which are obtained according to the description of fig. 2 to 3 above (410). For the identified cases, an adjusted estimated CM and/or PAR is calculated (420) according to the following.

The MPR is set according to a value for the maximum MPR and/or the minimum MPR (430). Preferably, the maximum MPR and/or the minimum MPR is calculated by the processing device 430 from the adjusted CM and/or PAR estimate (420), or the adjusted MPR estimate. If calculated based on the adjustment to the MPR, no adjustment to the CM and/or PAR is made.

The WTRU 400 may be configured to calculate either or both of the MPRs; and calculating the minimum MPR from either the CM or PAR, so that any combination can be selected for use. The estimate of CM and/or PAR may be a function of a pre-computed value represented by the alpha term or a function of the desired associated channel power of the transmitted signal (beta term), where the particular function of the beta term is a function of a particular physical parameter of the signal. The adjustment to this estimate may be from a pre-computed term.

To calculate one or two MPRs in the WTRU 400, first, for a TTI, the channel weight of the MAC-es is β, as an example of the configuration of the signal_c=15，β_d=6，A_hs=β_hs/β_c=max(Δ_ACKAnd Δ_CQI)=15/15，A_ec=β_ec/β_c=15/15，A_ed,=β_ed/β_c= 95/15. An example of this signal is signal U in R4-060176,3GPP TSG RAN 4Meeting # 38.

Second, using digital scaling, the WTRU 400 calculates the following digital channel weights: beta is a_c=22,，β_d=9，β_hs=22，β_ec=22，β_ed= 200. These weights are in a desired proportion to each other, and the sum of their squares is a desired constant.

Third, by using α in Table 3_CMAnd beta, and the digital channel weights and CM are calculated using equation 5_linearIs 1.0589, equal to 0.2487 dB.

Fourth, the estimate of CM is adjusted by subtracting 0.54dB, resulting in about-0.29 dB. Alternatively, in a linear form, the estimate is adjusted by multiplying 1.0589 by 0.883, resulting in about 0.93.

Fifth, the linear adjustment estimate of CM 0.94 is less than the first linear threshold in table 4; therefore, the maximum MPR is calculated as 0 dB.

Summarized by fig. 8, a process 800 for setting transmit power by the WTRU 400 calculating MPR is shown. Depending on the configuration, the adjustment factor and the pre-calculated alpha value are determined and processed in an offline processor (810). These values are stored in the WTRU 400 to help the WTRU 400 identify the configuration situation (820). Once the configuration is determined, an adjusted estimated CM and/or PAR is calculated (830). By using these adjusted estimated values, the maximum MPR and the minimum MPR are calculated (840), and the MPR is set. The MPR, theoretical maximum power and power control commands are combined (850) to set the transmit power (860).

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments and each feature or element can be used in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium, examples of which include Read Only Memory (ROM), Random Access Memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs), for execution by a general purpose computer or a processor.

Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of Integrated Circuit (IC), and/or a state machine.

A processor in association with software may be used to implement a radio frequency transceiver for use in a Wireless Transmit Receive Unit (WTRU), User Equipment (UE), terminal, base station, Radio Network Controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, bluetoothA module, a Frequency Modulation (FM) radio unit, a Liquid Crystal Display (LCD) display unit, an Organic Light Emitting Diode (OLED) display unit, a digital music player, a media player, a video game module, an Internet browser, and/or any Wireless Local Area Network (WLAN) module.

Claims (10)

1. A wireless transmit/receive unit, WTRU, comprising:

means for obtaining a first maximum power reduction, MPR, and a second MPR; wherein the first and second MPRs are obtained from at least a modulation type of an uplink transmission of the WTRU;

means for selecting the first or second MPR;

means for modifying a maximum output power of the WTRU in response to the selected first or second MPR; and

means for transmitting the uplink transmission at an output power that does not exceed the modified maximum output power.

2. The WTRU of claim 1, wherein the second MPR is obtained from at least an adjustment factor.

3. A method, the method comprising:

obtaining, by a wireless transmit/receive unit (WTRU), a first Maximum Power Reduction (MPR) and a second MPR; wherein the first and second MPRs are obtained from at least a modulation type of an uplink transmission of the WTRU;

selecting, by the WTRU, the first or second MPR;

modifying, by the WTRU, a maximum output power of the WTRU in response to the selected first or second MPR; and

transmitting the uplink transmission at an output power that does not exceed the modified maximum output power.

4. The method of claim 3, wherein the second MPR is obtained from at least an adjustment factor.

5. A wireless transmit/receive unit (WTRU), comprising:

an antenna;

means for determining a first Maximum Power Reduction (MPR) and a second MPR, the means for determining the first Maximum Power Reduction (MPR) and the second MPR operatively coupled to the antenna;

means for selecting an MPR based on the determined first and second MPRs; and

means for reducing a transmit power level based on the selected MPR.

6. The WTRU of claim 5, wherein the first MPR is compared to the second MPR to select the selected MPR.

7. A method, the method comprising:

determining, by a wireless transmit/receive unit (WTRU), a first Maximum Power Reduction (MPR) and a second MPR;

selecting, by the WTRU, an MPR based on the determined first and second MPRs; and

reducing, by the WTRU, a transmit power level based on the selected MPR.

8. The method of claim 7, wherein the first MPR is compared to the second MPR to select the selected MPR.

9. An integrated circuit, the integrated circuit comprising:

a circuit configured to determine a first Maximum Power Reduction (MPR) and a second MPR;

wherein the circuitry is further configured to select the MPR based on the determined first and second MPRs; and

wherein the circuitry is further configured to control a reduction in transmit power of a wireless transmit/receive unit (WTRU) based on the selected MPR.

10. The integrated circuit of claim 9, wherein the first MPR is compared to the second MPR to select the selected MPR.