KR101481580B1 - An uplink power control method for a system using ofdm/sc-fdm - Google Patents

Abstract

A method for adjusting the power difference between two signals continuously transmitted in a broadband wireless mobile communication system is disclosed. The difference between the power values of two signals successively transmitted through two different channels is set so as not to exceed a predetermined value. Alternatively, the difference between the power values of two signals successively transmitted through two different channels is set to have a predetermined value. By this method, the power transition interval between the two signals is shortened, and stable power control is possible.

Power control, power transition section

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an uplink power control method for a system using OFDM / SC-FDM,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide band wireless mobile communication system, and more particularly to an uplink power control.

One of the systems considered after the third generation wireless mobile communication system is an Orthogonal Frequency Division Multiplexing (OFDM) system capable of attenuating the inter-symbol interference effect with low complexity. OFDM converts serial input data into N pieces of parallel data and transmits the data on N orthogonal subcarriers. The subcarriers maintain orthogonality at the frequency dimension. Orthogonal Frequency Division Multiple Access (OFDMA) is a system in which a plurality of available subcarriers are independently provided to each user in a system using OFDM as a modulation scheme, thereby realizing a multiple access method It says.

One of the major problems with OFDM / OFDMA systems is that the Peak-to-Average Power Ratio (PAPR) can be very large. The large PAPR means that the peak amplitude of the transmission signal is larger than the average amplitude of the transmission signal. This phenomenon is caused by the fact that OFDM symbols overlap N different subcarriers, that is, N sinusoidal signals are superimposed. PAPR is especially handled in terminals that are sensitive to power consumption because they use batteries. To reduce power consumption, it is necessary to lower the PAPR.

One of the systems proposed for lowering the PAPR is a single carrier frequency division multiple access (SC-FDMA). SC-FDMA is a combination of SC-FDE (Single Carrier-Frequency Division Equalization) and FDMA (Frequency Division Multiple Access). SC-FDMA has characteristics similar to OFDMA in that it modulates and demodulates data in time domain and frequency domain using Discrete Fourier Transform (DFT), but it is advantageous in reducing transmission power because of low PAPR of the transmission signal . In particular, it can be said that it is advantageous for uplink communication from a terminal sensitive to transmission power to a base station in connection with battery use.

When the terminal transmits data to the base station, it is important to secure a wide coverage. Since the amplitude variation of the signal is reduced by the SC-FDMA system, the SC-FDMA system has a wider coverage than other systems when the same power amplifier is used. In the SC-FDMA scheme, the data symbols s are distributed using a DFT matrix before transmission. Subcarrier mapping is performed on the distributed vector x by a predetermined subcarrier allocation technique. (Inverse Discrete Fourier Transform) module to obtain a signal to be transmitted to the receiving side. A method of generating a transmission signal by the above-described method and transmitting the transmission signal to the receiving side is referred to as an SC-FDMA method.

In an LTE system, an uplink signal can be divided into a data signal, a control signal, and a pilot signal to be transmitted by a UE (User Equipment). In the scheduling of resources for uplink transmission, resources for transmission of data signals, resources for transmission of control signals, and transmission of SRS (Sounding Reference Signal) signals are divided in principle, The resource allocation methods are also different. That is, the frequency or time resource for the data signal, the frequency or the time resource for the control signal may be different from each other, and the SRS signal may be periodically transmitted using resources allocated in advance for each UE. For example, the data signal is transmitted through a Physical Uplink Shared Channel (PUSCH), the control signal is transmitted through a Physical Uplink Control Channel (PUCCH), and the SRS signal can be transmitted through an SRS channel.

Signals transmitted through different channels are transmitted at different times and are scheduled to have independent power. In this case, each channel is designed to have a power difference value of up to several tens of dB. Therefore, a transition interval of several tens of us (micro sec) is required in a channel change region, and there is a disadvantage that the accuracy of a signal existing in the transition region is reduced. That is, when a signal before or after a transition period that changes from one channel to another channel is amplified in a region where the linearity of the RF (Radio Frequency) amplifier is not ensured, distortion occurs, The signal can not be correctly decoded.

Therefore, there is a need to reduce the technique and transition interval for efficiently reducing the channel distortion, or to improve the accuracy.

An object of the present invention is to reduce the length of a power transition interval between two different signals continuously transmitted through different channels in order to perform stable signal control.

In the uplink OFDM / SC-FDM system, by setting a 'power difference maximum value' between a user data signal, a control signal, and a pilot signal, it is possible to limit a variation amount of power converted according to a channel, Offset) value. According to this method, the system can be designed to eliminate sudden power fluctuations between channels, thus enabling stable and efficient power control.

A signal in the uplink OFDMA / SC-FDMA system may be divided into a data signal for transmitting user data, a control signal related to the user information data, and a pilot signal designed to be known by the base station, have.

In the present invention, a 'maximum power difference' is set between a plurality of signals such as a data signal, a control signal, and a pilot signal transmitted by one user. 1) By doing so, power control can be performed so that the power difference value between the plurality of signals does not exceed the set 'power difference maximum value'. In other words, by setting a 'power difference maximum value' which can be used for all of a plurality of channels, the power of each channel can be set so that the power difference between channels becomes equal to or less than the set value. 2) Furthermore, according to the present invention, by setting a fixed power offset value for each channel pair, the power can be controlled so as to minimize abrupt power fluctuation between channels. In other words, by setting the power offset value for each channel pair based on the MCS, if the power value of one channel is changed by? P, the power value of the remaining channel is always changed by? P.

According to the present invention, stable power control is possible even in a power transition period which is a time point when a channel changes.

According to an aspect of the present invention, there is provided a signal power adjustment method for adjusting power of a plurality of signals transmitted through different channels in a broadband wireless mobile communication system, Transmitting a signal at a first transmit power (P1), determining a temporary transmit power (PT) for a second one of the plurality of signals, Determining a second transmit power (P2) based on a set 'Maximum of Power Difference', a first transmit power (P1) above and a temporary transmit power (PT) above, and And transmitting the second signal above with a second transmit power (P2) above.

The plurality of signals may include a data signal, a control signal, and an SRS signal.

Preferably, in the step of determining the second transmission power P2, the absolute value of the difference value between the second transmission power P2 and the first transmission power P1 is determined as the upper The second transmission power P2 can be determined so that the second transmission power P2 is equal to or smaller than the maximum transmission power P2 and is equal to or smaller than the predetermined P_MAX value.

At this time, in the step of determining the second transmission power, if the temporary transmission power PT is larger than the first transmission power P1 (PT > P1), the temporary transmission power (PT) P1 is greater than a predetermined value K (PT-P1> K), the above second transmission power P2 is higher than the first transmission power P1 P1) and the predetermined K value above (P2 = P1 + K). At this time, if the determined second transmission power P2 is equal to or greater than a predetermined P_MAX value, the above second transmission power P2 may be determined to be the above predetermined P_MAX value (P2 = P_MAX).

At this time, in the step of determining the second transmission power P2, if the temporary transmission power PT is larger than the first transmission power P1 (PT > P1) and the temporary transmission power PT (PT-P1 < K), the above-mentioned second transmission power P2 is the above-mentioned temporary transmission (PT-P1) May be determined as the power PT (P2 = PT).

At this time, in the step of determining the second transmission power P2, the temporary transmission power PT is smaller than the first transmission power P1 (PT < P1) If the difference (P1-PT) of the temporary transmission power (PT) is larger than the predetermined K value (P1-PT> K), the second transmission power (P2) May be determined as the difference (P1-K) of the predetermined K value (P2 = P1-K).

At this time, in the step of determining the second transmission power P2, the temporary transmission power PT is smaller than the first transmission power P1 (PT < P1) If the difference (P1-PT) of the temporary transmission power (PT) is smaller than the predetermined K value (P1-PT <K), the second transmission power P2 is determined as the temporary transmission power PT (P2 = PT).

In a broadband wireless mobile communication system according to another aspect of the present invention, a signal power adjustment method for adjusting power of a plurality of signals transmitted through different channels includes receiving a first signal among the plurality of signals as a first transmission power P1 ), Determining a temporary transmit power (PT) for the second one of the plurality of signals, determining a predetermined power offset of the second signal above for the first signal, Determining a second transmission power P2 based on the transmission power P1 and the temporary transmission power PT above and transmitting the second signal on the second transmission power P2 .

In addition to the first and second signals described above, there may be a third signal. At this time, the predetermined power offset of the third signal for the first signal may be different from the predetermined power offset of the second signal for the first signal above.

Preferably, the predetermined power offset above can be determined differently depending on the MCS level.

Preferably, the absolute value of the predetermined Reverse Power Offset of the first signal above for the second signal above may be different from the absolute value of the predetermined power offset above.

In addition, the predetermined reverse power offset of the first signal for the second signal and the predetermined power offset of the second signal for the first signal may have different signs.

According to another aspect of the present invention, there is provided a method of adjusting a power of a plurality of signals transmitted through different channels in a broadband wireless mobile communication system, the method comprising: P1), and transmitting a second one of the plurality of signals above at a second transmit power (P2), wherein the second transmit power (P2) above comprises a first transmit power Is a value obtained by adding the predetermined power offset of the above second signal to the above first transmission power (P1).

Preferably, if the power offset above is greater than 0 and the value of the power offset above the first transmission power (P1) above exceeds a predetermined P_MAX value, then the above second transmission power (P2) Can be the above P_MAX.

Preferably, if the power offset is less than zero and the power offset above the first transmit power P1 is equal to or less than zero, then the second transmit power P2, May be selected from a value greater than zero and less than the first transmission power (P1) above.

According to the present invention, by limiting the difference in transmission power between signals continuously transmitted through different channels, it is possible to shorten the power transition interval and improve the reliability of the signal in the power transition interval.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The detailed description set forth below in conjunction with the appended drawings is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details for a better understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details. For example, in the following description, certain terms are mainly described, but they need not be limited to these terms, and they may have the same meaning when they are referred to as arbitrary terms. Further, the same or similar elements throughout the present specification will be described using the same reference numerals.

Data, pilot, and control information are transmitted through the uplink. At this time, a band for UE information data to be transmitted in the uplink may be allocated or a transport format may be determined by a downlink control signal.

The pilot signal can be roughly divided into two types according to the use. The first pilot signal is an SRS pilot for measuring the channel quality (CQ) used for UE scheduling and adaptive modulation and coding (AMC). The second pilot is a pilot required to perform channel estimation and data demodulation in data transmission.

The control information can be divided into two types. The first control information is data-associated control information necessary for recovering data transmitted from the UE. The second is non-data-associated control information required for downlink transmission. For example, information related to the transport format or HARQ related information is data-association control information, and includes a channel quality indicator (CQI) for ACK / NACK for downlink HARQ operation and downlink adaptation, Data-association control information.

In the present invention, the term data is used in combination with user data or UE information data. Also, in this document, the power difference between two different 'signals' can mean the power difference between two different 'channels'. That is, two different signals may refer to two signals transmitted over two different channels.

In the conventional power control method, the PUSCH (data signal), the PUCCH (control signal), and the SRS (SRS signal) power are independently set and controlled. According to this conventional technique, the power difference value between different transmission signals can be large. The larger the power difference value is, the longer the power transition interval existing between the two signals becomes. At this time, the signal existing in the power transition section is distorted and the reliability is decreased. Therefore, the decoding performance decreases as the power transition interval becomes longer.

In order to overcome the drawbacks of the prior art, the present invention sets a 'power difference maximum value' between a plurality of different transmission signals. Next, the power of the signal to be transmitted next is set to be within the above-mentioned 'power difference maximum value'. According to this method, since the power transition period can be shortened compared with the prior art, the reliability of the signal in the signal power change period can be improved. In addition, since the power accuracy of each signal can be secured in a shorter time than the prior art, it can have excellent performance.

Hereinafter, embodiments according to the present invention will be described.

FIG. 1 is a block diagram of a conventional SC-FDMA transmission terminal.

The data symbols are input to the deserializer 110 and converted into parallel symbols. The parallel symbols are subjected to DFT processing in the DFT spreading module 120. The DFT-processed signal is converted into a serial signal through the P / S converter 150 via the subcarrier mapping unit 130 and the IDFT module 140. The output of the P / S converter 150 is converted into a transmission signal via the cyclic prefix inserter 160. [

2 shows an example of a UL subframe structure.

Referring to FIG. 2, the uplink subframe can be divided into a control region and a data region. The control area is an area for transmitting only the control signal, and is assigned to the control channel. The control channel may be referred to as a Physical Uplink Control Channel (PUCCH). A data area is an area for transmitting data, and is allocated to a data channel. The data channel may be referred to as a Physical Uplink Shared Channel (PUSCH). Generally, data and control signals in a UE may cause a PAPR problem, and therefore, each subframe is transmitted in the same subframe without being transmitted in the same subframe. The control signal is a signal other than a data signal. The control signal includes an ACK (Acknowledgment) / NACK (Negative-Acknowledgment) signal, a CQI (Channel Quality Indicator), a Scheduling Request (SR), a Precision Matrix Index RI (Rank Indicator) and the like. The control region and the data region are FDM (Frequency Division Multiplexing) because they use different frequency bands. The control region is located at the both edges of the system band, and the data region is located at the central portion of the system band. However, this is merely an example, and the arrangement of the control area and the data area on the subframe is not limited to the above. The positions of the control area and the data area may be switched with each other, and are not necessarily limited to the illustrated pattern.

In addition, the positions of the control area and the data area can be changed from time to time, and the boundary between the two areas is not separately determined. The positions and boundaries of the control area and the data area shown in FIG. 2 are values arbitrarily set for explaining the present invention. Thus, the boundaries can be defined in various ways. It is desirable that the base station and the terminal share the definition of the boundary.

The control channel information for one user is generally allocated in units of two consecutive slots. Two consecutive slots form one sub-frame. However, the above-mentioned control channel information located in the two slots are not the same in frequency but are shifted from each other. In particular, if the first slot is located at one end of the subframe, the second slot is located at the other end of the subframe. As described above, the slot allocated to each terminal can be frequency hopped on the subframe. A frequency diversity gain can be obtained by allocating one control channel for the UE to different frequency bands in different slots.

Also, if the number of users increases, the above-mentioned resource area (two consecutive slots) may exceed the acceptable capacity. In this case, another time-frequency resource area, i.e. another slot, can be additionally used. In this case, the additional resource area is located so as to be opposite to the resource area that has been used previously.

3 shows the structure of a transmitting end in which information bits are processed and transmitted.

In the LTE uplink, the transmission channels allocated as shown in FIG. 2 are transmitted through the antenna 150 through the RF filter 140 as shown in FIG. 3. At this time, the transmission power of the data channel can be expressed by Equation (1).

[Equation 1]

, 상위 계층(Layer)으로부터 주어지는PUSCH 전력 오프셋 파라미터(Parameter)인

, 경로 손실(Path-Loss), RRC(Radio Resource Controller)에 의해 주어지는 셀 고유의(cell specific) 파라미터에 따른

, 및 이전 전력 제어 상태와 연관된 현재의 전력 제어 조절 상태(Power Control Adjustment State)를 나타내는

에 의해 결정된다. 여기서,

는

일 수 있다.Here, the power of the data channel is the number of resource blocks allocated to the i &lt; th &gt;

, A PUSCH power offset parameter given from an upper layer

, Path-loss, and cell-specific parameters given by the Radio Resource Controller (RRC)

And a current power control adjustment state associated with the previous power control state.

. here,

The

Lt; / RTI &gt;

는 각 대역(band)에 따른 UE RF의 최대 송신 출력 파워를 나타내며, 표 1과 같이 표현 될 수 있다. 하지만 실제 UE에서의 송신

는 기지국의 스케줄러에 의해 주어진 최대값이 될 수도 있다.here

Represents the maximum transmission output power of the UE RF according to each band and can be expressed as shown in Table 1. However, the transmission in the actual UE

May be the maximum value given by the scheduler of the base station.

[Table 1]

Also, the transmission power of the control channel can be expressed by Equation (2).

&Quot; (2) &quot;

는 PUCCH 포맷에 따라 변하는 비트 수, 상위 계층에서 주어지는 PUCCH 전력 오프셋 파라미터인

, 경로 손실, 및 이전 전력 제어 상 태와 연관된 현재의 전력 제어 조절 상태(power control adjustment state)를 나타내는

에 의해 결정된다. 여기서,

는 [-135, -89]dBm일 수 있다.here

Is the number of bits varying according to the PUCCH format, the PUCCH power offset parameter given in the upper layer

The path loss, and the current power control adjustment state associated with the previous power control state.

. here,

May be [-135, -89] dBm.

Finally, the transmission power of the SRS signal can be expressed by Equation (3).

&Quot; (3) &quot;

은 [-10.5, 12]dB 사이의 값을 갖는, 상위 계층에서 주어지는 UE 마다 특정되어 주어지는 값일 수 있다.

는 자원 블록의 개수로 표현되는 SRS를 전송하는 대역폭을 나타낸다. 따라서 수학식 3에 나타낸 5개의 파라미터의 값들에 의해 SRS 전송파워가 결정된다.here

May be a value given for each UE given in the upper layer, having a value between [-10.5, 12] dB.

Represents a bandwidth for transmitting the SRS represented by the number of resource blocks. Therefore, the SRS transmission power is determined by the values of the five parameters shown in Equation (3).

As shown in the above equation, each channel power can have different values depending on the time and the frequency to be transmitted. Also, in order to convert power in a power transition period for transmitting another channel after one channel transmission is terminated, a transition interval of several to several tens us is required, and the accuracy is significantly lowered. Therefore, the signal transmitted at the start and end of the transition period is distorted, thereby reducing the reliability of the signal. Therefore, in order to prevent the signal of the transition period from being distorted, it is necessary to reduce the rate of change of power or improve the accuracy of power.

In the present invention, the power transition period can be reduced by limiting the power of the data signal (data channel), control signal (control channel), and SRS signal (SRS channel) transmitted in the uplink within a predetermined range. Therefore, the time taken to stabilize the power can be significantly reduced. Further, according to the power control method of the present invention, stability against power change can be secured quickly.

&Lt; Example 1 >

According to an embodiment of the present invention, a 'power difference maximum value' between the channels is set, and a difference value of the power of each signal is set to a value lower than the set value. That is, the current state or the power of the signal transmitted in the current frame becomes the reference value, and from this reference value, the power of the other signal to be transmitted in the next state or the next frame is calculated, Can be calculated. At this time, the power value of the other signal is adjusted so that the difference value of the above two powers is not larger than the 'power difference maximum value' of two predetermined signals. If the power value of one signal transmitted from one user at a certain time is set to an arbitrary value P, the power of another signal transmitted at the next time point is greater than (P- 'power difference maximum value') and (P + Power difference maximum value &quot;) or less.

This 'power difference maximum value' can be used to define a range in which the power of the signal fluctuates. Therefore, the power transition interval between different signals can be reduced, and the time required for power stabilization can be reduced.

&Lt; Example 2 >

According to another embodiment of the present invention, the power offset between each signal is set in advance according to the MCS determined by the scheduler, and when the signal changes, the power is changed by the preset power offset. That is, when the power of a signal transmitted at an arbitrary point is set to a certain value P, the power of another signal transmitted at another point of time is set to be always different from the set P value by a predetermined power offset .

For example, the power offset of signal 2 for signal 1 may be set to? ₁₂ . At this time, when the power value of the signal 1 is P ₁ , the power value of the signal 2 is the power value P ₁ of the signal 1 plus the power offset ₁₂ of the signal 2 of the signal 1. Also, the power offset of signal 3 for signal 1 can be set to? ₁₃ . At this time, if the power value of the signal 1 is P ₁ , the power value of the signal 3 is the power value P ₁ of the signal 1 plus the power offset Δ ₁₃ of the signal 3 for the signal 1. That is, when a plurality of signals are transmitted and a power offset value between the signals is predetermined, if the power value of one of the plurality of signals is determined, the power value of other signals may be automatically determined.

By limiting the range of the power offset value, it is possible to reduce the power transition period between different signals, thereby reducing the time required for power stabilization.

FIG. 4 shows power changes with time of three signals transmitted through an LTE uplink.

Referring to FIG. 4, in the N-th subframe, a data signal is transmitted with x dBm power through a channel PUSCH, and then in a (N + 1) th subframe, a control signal is transmitted with a power of y dBm through a channel PUCCH Then, in the (N + 2) -th subframe, the data signal is transmitted through the channel PUSCH and the SRS signal is transmitted at the power of z dBm.

Tables 2 and 3 below illustrate the parameters that can be used to apply the embodiment 1 described above. In Table 2 and Table 3, K, L, M, K1, L1, and M1 denote the 'power difference maximum value' in units of dB.

When the above-described first embodiment is applied to the example of Fig. 4, the power control is performed as follows. The 'power difference maximum value' between the respective channels can have the same value K regardless of the combination of channels as shown in the second column of Table 2. Alternatively, the 'power difference maximum value' may have a different 'power difference maximum value' for different channel pairs as in the third column of Table 2. That is, the 'power difference maximum value' is set to K dB between PUSCH and PUCCH, 'power difference maximum value' is set to L dB between PUCCH and SRS, and 'power difference maximum value' is set between SRS and PUSCH M &lt; / RTI &gt; dB.

[Table 2]

Alternatively, as shown in Table 3, it may have different values depending on whether the power is increasing or decreasing.

For example, as shown in FIG. 4, when the PUCCH is changed to the PUSCH, the power is decreased, but when the PUSCH is changed to the PUCCH, the power may be increased.

At this time, when the power is changed from the PUSCH to the PUCCH as shown in Table 3, the 'power difference maximum value' K1 becomes a positive value (K1> 0). On the contrary, when the power decreases from PUCCH to PUSCH, The value 'K1' has a negative value (K1 <0). Also, as shown in the second row of Table 3, when the power increases regardless of the combination of the channels, the 'power difference maximum value' K1 is set to K1> 0, and when the power decreases, the 'power difference maximum value' This K1 can be set to K1 < 0.

Alternatively, as shown in the third row of Table 3, the 'power difference maximum value' may be set differently for each combination of channels. That is, for example, when the power is changed from SRS to PUCCH and the power increases, the 'power difference maximum value' can be set to L1 (L1> 0). Conversely, when the power decreases from PUCCH to SRS, Can be set to L1 (L1 &lt; 0). When the power is changed from the PUSCH to the SRS and the power is increased, the maximum power difference value can be set to M1 (M1> 0). On the other hand, when the power is reduced from SRS to PUSCH, M1 (M1 < 0).

[Table 3]

At this time, the initial transmission power of the signal transmitted through the uplink can be determined by the base station. At this time, the power value in the current state always becomes the reference value. As shown in FIG. 4, when the PUSCH is transmitted at x dBm, the reference value is x. At this time, if the power of the PUCCH to be transmitted in subframe N + 1 is determined to be y dBm, y can be further adjusted through the following steps.

(1) First, it is determined whether x-y is 0, a positive number, or a negative number.

(2) If x-y = 0, y = x is determined. That is, the value of y is maintained.

(3) If xy is negative and the absolute value of xy is greater than the predetermined value k, then y = x + k. In addition, where ten thousand and one y is adjusted by y = P _max and P _max surface is equal to or greater.

(4) If x-y is negative and the absolute value of x-y is smaller than the predetermined value k, the y value is maintained.

(5) If x-y is positive and the value of x-y is greater than a predetermined k, then y = x-k.

(6) If x-y is negative and the value of x-y is smaller than the predetermined value k, the value of y is maintained.

5 is for explaining a method of adjusting the transmission power so that the inter-channel power offset has a constant value.

5 shows that in the subframe N, the data signal is transmitted at x dBm power through the channel PUSCH and then the SRS signal is transmitted at y dBm power. Then, in the subframe N + 1, the data signal is transmitted through the channel PUSCH to x + 隆 dBm, and then in the subframe N + 2, the control signal is transmitted with a power of z dBm through the channel PUCCH.

When the above-described second embodiment is applied to the example of Fig. 5, the power control is performed as follows.

The initial transmission power of the channel transmitted on the uplink is determined by the base station, and the power value in the current state always becomes the reference value. When the data signal of the N-th subframe is being transmitted at x dBm, power ramping can be performed even in the same subframe when the SRS signal exists in the same N-th subframe. If the power of the SRS signal is determined to be y dBm, the power offset between the PUSCH and the SRS is M dB as shown in Table 3. Thus, the y value can be readjusted by the following method.

(1) First, find y ₁ = x + M dBm. (Where M may be a +/- value)

(2) If yy ₁ > 0 and y ₁ is greater than or equal to P _max , then y = P _max dBm is reset.

                     Otherwise, it is reset to y = x + M dBm.

(3) If yy ₁ < 0, then y = x + M dBm is reset.

The values of K, L, M, K1, L1, and M1 shown in Tables 2 to 3 can be obtained through various experiments. In addition, the power offsets in Tables 2 and 3 may vary depending on the MCS. In addition, the power of the signal used in the above embodiments can be expressed by the absolute value [Instantaneous Values] [dBm]. Alternatively, the power density per frequency unit can be expressed in terms of dBm / Hz using PSD (Power Spectrum Density).

The 'power difference maximum value' and the optimal value of the power offset value of the present invention can be determined through the following process. First, the power change of three signals (data signal, control signal, and SRS signal) is observed and is shown as a CDF (Cumulative Distribution Function). Then, a power change interval that satisfies a PDF (Probability Density Function) value of 95% or more of each signal can be set, and two optimal parameters can be selected and determined.

Hereinafter, a signal power adjustment method according to an embodiment of the present invention will be described.

(First signal) among the plurality of signals including the data signal, the control signal, and the SRS signal transmitted through the PUSCH, PUCCH, and SRS channels, respectively, is transmitted with the first transmission power P1 . The control signal (second signal) may then be transmitted following the data signal. At this time, the temporary transmission power PT may be set to determine the power for transmission of the control signal. The above temporary transmission power PT can be used as it is as the second transmission power P2 for the control signal. Or the second transmission power P2 may be separately determined by another criterion. Hereinafter, a method for determining the second transmission power P2 for the control signal will be described in detail.

The second transmit power may have any of the following values.

First, if PT> P1 and PT-P1> K, then P2 = P1 + K. At this time, K is a value used to limit the difference value of power of two signals successively transmitted as a predetermined value. If P2> P_MAX at this time, P2 = P_MAX can be set. Here, P_MAX may be the upper limit value that P2 should not exceed in any case. P_MAX is a value set separately from the power offset K1.

Second, if PT> P1 and PT-P1 <K, then P2 = PT. That is, since the PT-P1 value is smaller than the limit value K of the power difference between the two signals continuously transmitted, the temporary transmission power PT can be used as the second transmission power as it is.

Third, in the case of PT < P1 and P1-PT > K, P2 = P1-K. That is, since the difference between the temporary transmission power PT and the previously transmitted first transmission power P1 exceeds the limit value K, the temporary transmission power PT can not be used as it is at the second transmission power.

Fourth, PT <P1 and P1-PT <K In this case, P2 = PT. That is, since the P1-PT value is smaller than the limit value K of the power difference of the two signals successively transmitted, the temporary transmission power PT can be used as the second transmission power as it is.

In this embodiment, the data signal is selected as the first signal and the control signal is selected as the second signal, but the present invention is not limited thereto. That is, the first signal and the second signal may be arbitrary signals transmitted through different channels.

Hereinafter, a method of adjusting power of two different signals according to another embodiment of the present invention will be described.

Among the plurality of signals including the data signal, the control signal, and the SRS signal transmitted through the PUSCH, PUCCH, and SRS channels, respectively, for example, the data signal is transmitted as the first signal in the first transmission power P1 . Following the next data signal, the control signal as the second signal may be transmitted at the second transmit power P2. At this time, the second transmission power P2 may be limited to a value obtained by adding K1, which is the power offset of the control signal to the data signal, to the first transmission power P1.

값을 초과하는 경우에는, 제2 송신 전력(P2) 은 상기

로 설정될 수 있다. 여기서,

는 P2가 어떠한 경우에도 초과해서는 안 되는 상한 값일 수 있다.

는 전력 오프셋 K1과는 별도로 설정되는 값이다. 또한 만일 제2 송신 전력(P2)이

값보다 작은 경우, 제 2 송신 전력 (P2)은 전력 오프셋인 K1을 제 1 송신 전력(P1)에 더한 값이 된다. 반대로, 전력 오프셋 K1이 0보다 작을 경우, 전력 오프셋 K1을 제1 송신 전력(P1)에 더한 값이 0과 같거나 0보다 작은 경우에는, 제2 송신 전력(P2)은 전력 제 1송신전력(P1)에서 오프셋만큼 줄어든 값으로 설정된다.At this time, if the power offset K1 is greater than 0 and the power offset K1 is added to the first transmission power P1,

, The second transmission power P2 is higher than the second transmission power P2

Lt; / RTI &gt; here,

May be the upper limit value that P2 should not exceed in any case.

Is a value set separately from the power offset K1. Also, if the second transmission power P2 is

, The second transmission power P2 becomes a value obtained by adding the power offset K1 to the first transmission power P1. Conversely, if the power offset K1 is less than zero, then the second transmission power P2 is equal to the power first transmission power P1 when the power offset K1 plus the first transmission power P1 is equal to or less than zero Lt; RTI ID = 0.0 &gt; P1. &Lt; / RTI &gt;

Here, a power offset may be separately set for each pair of the plurality of signals. For example, the power offset between the mutual data signal and the control signal may be set to K1, the power offset between the mutual SRS signal and the control signal may be set to L1, and the power offset between the mutual data signal and the SRS signal may be set to M1, respectively.

In this embodiment, the data signal is selected as the first signal and the control signal is selected as the second signal, but the present invention is not limited thereto. That is, the first signal and the second signal may be arbitrary signals transmitted through different channels.

The present invention relates to a power control scheme for a data signal, a control signal, and an SRS signal transmitted on an uplink. In the present invention, the power offset is adjusted in such a manner that a 'power difference maximum value' is set during power control or a maximum power limit value is changed according to MCS. Thus, it is possible to improve the accuracy of the transmitted power by ensuring the linearity of the power amplifier and minimizing the power transition period. Particularly, according to the present invention, the reliability of a signal in a section where power is changed is improved.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like which performs the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

The present invention can be applied to devices such as a mobile station and a base station used in a broadband wireless mobile communication system.

FIG. 1 is a block diagram of a conventional SC-FDMA transmission terminal.

2 shows an example of a UL subframe structure.

3 shows the structure of a transmitting end in which information bits are processed and transmitted.

FIG. 4 shows power changes with time of three signals transmitted through an LTE uplink.

5 is for explaining a method of adjusting the transmission power so that the inter-channel power offset has a constant value.

Claims (13)

A signal power adjustment method for adjusting power of a plurality of signals transmitted through different channels in a broadband wireless mobile communication system, Transmitting a first one of the plurality of signals at a first transmission power (P1); Determining a temporary transmit power (PT) for a second one of the plurality of signals; Based on the maximum power difference (MPD), the first transmission power (P1), and the provisional transmission power (PT) set for the first signal and the second signal pair, 2 determining a transmit power (P2); And Transmitting the second signal with the second transmit power (P2) / RTI &gt; Signal power adjustment method. The method according to claim 1, The absolute value of the difference value between the second transmission power P2 and the first transmission power P1 is equal to or smaller than the 'power difference maximum value' in the step of determining the second transmission power P2 In addition, the second transmit power (P2) a method for determining the second transmit power (P2) is less than or equal to a predetermined value P_ _MAX, signal power controller. The method according to claim 1, (PT) is greater than the first transmission power (P1) and the temporary transmission power (PT) is greater than the first transmission power (P1) If the difference value PT-P1 of the power P1 is larger than the predetermined K value (PT-P1> K), the second transmission power P2 is higher than the first transmission power P1 and the predetermined (P2 = P1 + K) determined as the sum of the K values. The method of claim 3, Ten thousand and one has the determined second transmission power (P2), if this is more than the predetermined P _MAX value, the second transmit power (P2) is a method (P2 = P _MAX), a signal power control is determined to be the predetermined P _MAX value . The method according to claim 1, (PT) is greater than the first transmission power (P1) and the temporary transmission power (PT) is greater than the first transmission power (P1) When the difference value PT-P1 of the power P1 is smaller than a predetermined K value (PT-P1 <K), the second transmission power P2 is determined as the temporary transmission power PT (P2 = PT), Signal power adjustment method. The method according to claim 1, The method of claim 1, wherein in determining the second transmission power (P2), the temporary transmission power (PT) is less than the first transmission power (P1) If the difference value P1-PT of the power PT is greater than a predetermined value K (P1-PT> K), the second transmission power P2 is equal to the first transmission power P1, (P2 = P1-K) determined as the difference (P1-K) of the K values. The method according to claim 1, The method of claim 1, wherein in determining the second transmission power (P2), the temporary transmission power (PT) is less than the first transmission power (P1) If the difference (P1-PT) of the power PT is smaller than the predetermined K value (P1-PT <K), the second transmission power P2 is determined as the temporary transmission power PT = PT), Signal power adjustment method. A signal power adjustment method for adjusting power of a plurality of signals transmitted through different channels in a broadband wireless mobile communication system, Transmitting a first one of the plurality of signals at a first transmission power (P1); Determining a temporary transmit power (PT) for a second one of the plurality of signals; Determines a second transmit power (P2) based on a predetermined power offset of the second signal relative to the first signal, the first transmit power (P1), and the provisional transmit power (PT) ; And Transmitting the second signal with the second transmit power (P2) / RTI &gt; Signal power adjustment method. 9. The method of claim 8, Wherein the predetermined power offset is determined differently according to a Modulation Coding Scheme (MCS) level. 9. The method of claim 8, Wherein an absolute value of a predetermined reverse power offset of the first signal for the second signal is different from an absolute value of the predetermined power offset. A signal power adjustment method for adjusting power of a plurality of signals transmitted through different channels in a broadband wireless mobile communication system, Transmitting a first one of the plurality of signals at a first transmission power (P1); And Transmitting a second one of the plurality of signals at a second transmission power (P2) Lt; / RTI &gt; Wherein the second transmit power P2 is a value (P2 = P1 + K) obtained by adding the predetermined power offset (K) of the second signal to the first signal to the first transmit power (P1) Signal power adjustment method. 12. The method of claim 11, Said predetermined power offset (K) is greater than 0 (K> 0), if the power offset (K) exceeds P_ _MAX value, the value is determined in advance added to the first transmission power (P1) is (P1 + K> P_ _MAX), said second transmit power (P2) is (P2 = P_MAX), a signal power control method in the P_ _MAX. 12. The method of claim 11, Wherein the second transmission power P2 is a value obtained by adding the power offset K to the first transmission power P1 when the predetermined power offset K is less than 0 + K), < / RTI &gt; Signal power adjustment method.

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