CN104812042A - Method for controlling transmission power - Google Patents

Abstract

The invention discloses a method for controlling transmission power. This method is applicable to the case where D2D transmission and uplink transmission share frequency division multiplexing uplink resources. The method on the base station side includes: A. Configuring power control parameters for the D2D user end and the uplink user end; B. Broadcasting the configured power control parameters to the wireless network through system information or configuration information; C. Measuring the The interference degree of the transmission signal sent by the D2D user end to the upload signal of the uplink user end; D. According to the measurement result of the interference degree, adjust part of the power control parameters; E. Pass the adjusted power control parameters through System information or configuration information is broadcast to the wireless network. The invention also discloses corresponding methods implemented by the D2D user end and the uplink user end.

Description

A method of controlling transmission power

technical field

The present invention mainly relates to the technical field of wireless communication, and in particular, relates to a method for controlling the transmission power of a user end in a wireless network.

Background technique

In the discussion of 3GPP D2D (device to device: device to device) (for example, the research project in R12), it has been agreed that D2D transmission can be carried out on the uplink carrier (in frequency division multiplexing FDD mode) or in the uplink subframe (in In time division multiplexing TDD mode), configurable time period and frequency resources are occupied. This means that, like a common cellular network, in D2D transmission (such as D2D discovery), downlink carriers or subframes are still used for downlink data transmission. In this case, there will inevitably be a problem: during the activated D2D transmission continues to be in the configured D2D transmission timing (here it is assumed that frequency division multiplexing is universal), some uplink control information still needs to be transmitted (for example, ACK/NACK feedback of downlink data packets). Therefore, in a D2D subframe, the transmission of some cellular channels (eg, PUCCHs) will have to be frequency-division multiplexed with the D2D transmission to share uplink frequency resources in the wireless network. In this case, it is natural to imagine such a technical problem: Will the D2D transmission have adverse effects on the information in the PUCCH received by the base station? If so, how can this potential adverse effect be avoided?

In fact, although the resources used for D2D transmission and the resources used for PUCCH transmission are mutually orthogonal frequency resources, D2D transmission does have a potential impact on frequency division multiplexed PUCCH transmission. This potential impact stems from in-band emission interference from D2D transmissions. An example model of in-band emission interference defined in 3GPP TR36.843v1.0 is shown in Figure 1. The signal in the physical resource block No. 5 will cause general in-band transmission interference (for example, interference to physical resource blocks No. Interference to physical resource block No. 25) and in-band transmission interference formed by IQ mirroring (for example, interference to physical resource block No. 46). Therefore, we can easily imagine that the D2D transmission, especially the D2D transmission near the base station, will cause significant in-band interference to the resources occupied by the PUCCH. Figure 2 shows a system-level evaluation result of "in-band interference over thermal noise" (IBIoT: in-band interference over thermal noise), where the D2D discovery transmitter that generates the in-band interference uses a fixed 23dBm transmission power. From the figure, we can find that the ratio of in-band interference to thermal noise can be as high as above 40dB on average, which completely submerges the useful PUCCH signal at the receiver side of the base station. So be badly in need of finding a technical solution to solve this problem, and this just is the technical problem to be solved by the present invention.

Contents of the invention

In order to solve the above technical problems, according to one aspect of the present invention, a method for controlling the transmission power P _D2D of a D2D user terminal at the base station side is disclosed, the D2D user terminal is located within the coverage of the base station, and the D2D user terminal The terminal and other uplink user terminals that need to send uplink information to the base station share the uplink frequency resources in the wireless network by means of frequency division multiplexing, wherein: A. configure power for the D2D user terminal and the uplink user terminal Control parameters; B. Broadcast the configured power control parameters to the wireless network through system information or configuration information; C. Measure the interference of the transmission signal sent by the D2D user end on the upload signal of the uplink user end D. Adjust part of the power control parameters according to the measurement result of the interference degree; E. Broadcast the adjusted power control parameters to the wireless network through system information or configuration information.

Specifically, the power control parameters include: the carrier maximum transmission power parameter P _CMAX,C configured for the D2D user end and the uplink user end; the common PUCCH power control parameter P _{O_Norminal_PUCCH} configured for the uplink user end; D2D specific power control parameter Δ _D2D configured by the D2D UE.

Specifically, in the step D, when the measurement result of the interference degree exceeds a predetermined limit range, reduce the value of the D2D specific power control parameter _ΔD2D ; when the measurement result of the interference degree is lower than the predetermined When the predetermined limit range, increase the value of the D2D specific power control parameter Δ _D2D ; when the measurement result of the interference degree is within the predetermined limit range, maintain the value of the D2D specific power control parameter Δ _D2D .

In particular, step A also includes, a1. a preset signal-to-noise ratio threshold γ _PUCCH , which represents the critical value of the ratio of the uplink user terminal's upload signal to in-band interference at the base station side, wherein, The in-band interference is: the interference of the transmission signal sent by the D2D user end on the uplink signal of the uplink user end; a2. The D2D specific power control parameter Δ _D2D is configured according to the signal-to-noise ratio threshold γ _PUCCH .

Specifically, in the step a2: according to the equation P _{O_Norminal_PUCCH} -(P _{O_Norminal_PUCCH} +Δ _D2D +10log ₁₀ (N _{PRB_D2D} )-36)>γ _PUCCH , configure the value of the D2D specific power control parameter Δ _D2D , wherein, The N _{PRB_D2D} is the number of physical resource blocks used by the D2D UE in the frequency domain.

Particularly, in the step A, the D2D specific power control parameter _ΔD2D is a preset value according to the transmission status of the wireless network.

Specifically, in the step D, when the measurement result of the degree of interference exceeds a predetermined limit range, a dedicated PUCCH power control parameter P _O-UE-PUCCH is configured for the uplink UE, and the dedicated PUCCH The power control parameter P _{O_UE_PUCCH} is used to increase the transmit power of the uplink UE.

In particular, it also includes: configuring the quantization set of the transmission power P _D2D , and broadcasting the quantization set to the wireless network, and the elements in the quantization set The corresponding relationship with the transmission power P _D2D is:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0,1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; or</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.$

Wherein, {P ₀ , P ₁ , ..., P _M-1 } is the quantization set of the transmission power P _D2D , and M is the number of elements in the quantization set.

Specifically, in the step A, it also includes configuring a limited set of D2D transmission resources, the limited set of D2D transmission resources is composed of limited D2D transmission resources, wherein, in the frequency domain, the limited D2D transmission resources It is relatively far away from the transmission resources used by the uplink UE to send uplink information; in the step B, it also includes broadcasting the limited set of D2D transmission resources to the wireless network through system information or configuration information.

According to another aspect of the present invention, a method for controlling the transmission power P _D2D of a D2D user terminal on the D2D user side is disclosed. The D2D user terminal is located within the coverage of the base station. The uplink user terminal that the base station sends the uplink information jointly uses the uplink frequency resources in the wireless network by means of frequency division multiplexing, wherein: periodically receives the system information or configuration information broadcast by the base station, and obtains power control information therefrom parameter; measure the path loss PL from the base station; determine the transmission power P _D2D of the D2D UE according to the power control parameter and the path loss.

Specifically, the power control parameters include: the carrier maximum transmission power parameter P _CMAX,C configured for the D2D user end and the uplink user end; the common PUCCH power control parameter P _{O_Norminal_PUCCH} configured for the uplink user end; D2D specific power control parameter Δ _D2D configured by the D2D UE.

Specifically, the transmission power P _D2D of the D2D UE is determined according to the formula: P _D2D =min{P _{CMAX, c,} P _{O_Nonninal_} P _UCCH +PL+Δ _D2D }.

In particular, it also includes: receiving the quantization set {P ₀ , P ₁ , ..., _PM-1 } sent by the base station, according to the formula: ${\hat{P}}_{\mathrm{D.}2\mathrm{D.}}=\left\{\begin{array}{cc}{P}_{m-1},& P_{\mathrm{D.}2\mathrm{D.}}\&Greater\; Equal;P_{m-1}\\ P_m,& P_{m+1}>P_{\mathrm{D.}2\mathrm{D.}}\&Greater\; Equal;P_m,m=\mathrm{0,1},...,m-2\\ 0\mathrm{or}{P}_0,& P_{\mathrm{D.}2\mathrm{D.}}<P_0\end{array}\right.$ Quantize the transmission power P _D2D of the D2D user end, and convert the quantized transmission power As the transmission power of the D2D UE, M is the number of elements in the quantization set.

In particular, it also includes: receiving system information or configuration information broadcast by the base station, and obtaining a limited set of _D2D transmission resources therefrom; When ₀ , use the limited D2D resources in the limited set of D2D transmission resources as the transmission resources for D2D transmission; wherein, in the frequency domain, the limited D2D transmission resources are farther from the distance used by the uplink UE to send uplink information Transmission resources are relatively far away.

According to another aspect of the present invention, a method for controlling the transmission power of an uplink user terminal on the uplink user side is disclosed. The uplink user terminal is a user terminal that needs to send uplink information to a base station, and the D2D user terminal is located at the base station. Within the coverage area, the D2D user end and the uplink user end jointly use uplink frequency resources in the wireless network through frequency division multiplexing, wherein: periodically receive system information or configuration information broadcast by the base station, and obtain power control parameters therefrom; determine the transmission power of the uplink user terminal according to the public PUCCH power control parameter P _{O_Norminal_PUCCH} in the power control parameters; wherein, when the RRC signaling in the downlink channel of the uplink user terminal is obtained Dedicated PUCCH power control parameter P _O-UE-PUCCH ; determine the transmission power of the uplink user terminal according to the common PUCCH power control parameter P _{O_Norminal_PUCCH} and the dedicated PUCCH power control parameter P _O-UE-PUCCH .

The solution disclosed in the present invention has the following advantages: when the wireless network implements the D2D transmission application, it can avoid the interference of the D2D transmission on the PUCCH channel in the uplink transmission, and overcome the problem of the D2D transmission using fixed transmission power in the prior art. The in-band transmission interference caused by the uplink transmission improves the signal-to-noise ratio of the PUCCH channel and improves the use efficiency of transmission power.

Description of drawings

Through the following detailed description of the embodiments shown in conjunction with the drawings, the above-mentioned and other features of the present invention will be more obvious, and the same or similar symbols in the drawings of the present invention represent the same or similar steps;

Figure 1 shows an example model diagram of in-band emission interference defined in 3GPP TR36.843v1.0;

Figure 2 shows a system-level evaluation result of "in-band interference over thermal noise ratio" (IBIoT: in-band interference over thermal noise) on the PUCCH physical resource block;

Fig. 3 shows a flow chart of a method for controlling the transmission power PD2D of a D2D user terminal at the base station side disclosed in the present invention;

Fig. 4 shows a flow chart of a method for controlling transmission power P _D2D at the D2D user side according to the present invention;

FIG. 5 shows a flow chart of a method for controlling the transmission power of an Uplink user terminal at the Uplink user side according to the present invention;

6 shows a schematic diagram of the cumulative distribution function (CDF) of the signal-to-interference-plus-noise ratio (SINR) on the PUCCH signal received at the base station side;

Figure 7 shows a schematic diagram of the cumulative distribution function (CDF) of D2D transmission power with and without power control; and

Fig. 8 shows a schematic diagram of the cumulative distribution function (CDF) of the signal-to-interference-plus-noise ratio (S1NR) on the D2D receiver with and without power control.

Detailed ways

In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings show, by way of example, specific embodiments in which the invention can be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. It should be noted that although the steps of the relevant methods in the present invention are described in a specific order herein, this does not require or imply that these operations must be performed in this specific order, or that all shown operations must be performed to achieve the desired As a result, instead, the steps described herein may be performed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and/or one step may be decomposed into multiple steps for execution.

In the introduction of this article, for the convenience of explanation, for the user end that transmits data in D2D mode, we call it D2D user end; for the user end that sends uplink data (such as PUCCH) to the corresponding base station in the wireless network, we call it It is called the uplink client.

It should be pointed out that the D2D UE and the uplink UE in the present invention are located in the same coverage area of the base station, and the D2D UE and the uplink UE jointly use the uplink frequency resources in the wireless network by means of frequency division multiplexing. That is, the method disclosed in the present invention is applicable to the case where D2D transmission and uplink transmission share frequency division multiplexing uplink resources.

In the 3GPP D2D research, it is assumed that the D2D UE uses a fixed transmit power (for example, 23dBm). Under the fixed transmission power configuration, the UE close to the base station will cause high in-band interference (as shown in FIG. 2 ) to the uplink data (such as data in the PUCCH) received by the base station from the uplink UE. In order to reduce the impact of D2D transmission on the uplink data received by the base station, the present invention configures the D2D transmission power in an open-loop power control mode to replace the original fixed transmission power mode.

Fig. 3 shows a flow chart of a method for controlling the transmission power P _D2D of a D2D user terminal at the base station side according to the present invention, the method slows down the uplink transmission of transmission signals between D2D user terminals to the uplink user terminal signal interference. Wherein, the D2D UE and the uplink UE are located within the signal coverage of the base station.

In step 302, the base station configures power control parameters for the D2D UE and the uplink UE.

Specifically, for the open-loop power control, the D2D transmission power is not fixed, and the D2D UE needs to dynamically set the transmission power according to the power control parameters. In order to enable the D2D UE to properly set the transmission power, according to an embodiment disclosed in the present invention, the base station configures the following power control parameters for the D2D UE:

P _{CMAX, C} : the unit is dBm, which represents the maximum transmission power allowed by each carrier of all UEs covered by the base station.

Δ _D2D : the unit is dB, which is a specific power control parameter of D2D, which represents the correction value of the transmission power, and is used to correct the magnitude of the transmission power. It is used by all D2D users covered by the base station. The base station can properly set the D2D specific power control parameters according to specific application conditions. This parameter can be set according to the formula (1) shown below:

P _{ONorminal_PUCCH} -(P _{O_Norminal_PUCCH} +Δ _D2D +10log ₁₀ (N _{PRB_D2d} )-36)>γ _PUCCH (1) Wherein, the left side of the formula (1) indicates that the PUCCH signal received by the base station and sent by the uplink user terminal is close to the base station The power ratio of in-band interference caused by D2D transmission. The parameter γ _PUCCH on the right side of the formula represents an assumed SIR (Signal to Noise Ratio) threshold. The symbol N _{PRB_D2D} represents the number of physical resource blocks used by the D2D UE in the frequency domain. Symbol -36 indicates the initial level of in-band interference (for example, the power diagram shown in Figure 1, the initial level of signal and interference are both -36dB), according to the initial level of in-band interference in the system, this value Can be replaced with any value. (P _{O_Norminal_PUCCH} +Δ _D2D +10log ₁₀ (N _{PRB_D2d} )-36), represents the in-band interference caused by D2D transmission near the base station.

For example, assuming N _{PRB_D2D} is 44 and γ _PUCCH is -3dB, we can obtain Δ _D2D < 22.56(dB). It should be pointed out that obtaining the Δ _D2D through the above formula (1) is one of many ways to configure the Δ _D2D . In actual implementation, other setting methods are not excluded. For example, a value can be estimated according to the transmission status of the wireless network as the value of the D2D specific power control parameter _ΔD2D . Similarly, it can also be set according to actual operating experience. set the value.

It should also be noted that in this example, the set value of the D2D specific power control parameter _ΔD2D configured in step 302 is only an initial value and may need further adjustment according to actual measurement and PUCCH.

In addition, the base station also configures the following power control parameters for the uplink UE:

P _{O_Norminal_PUCCH} : the unit is dBm, which is the common power control parameter of the uplink user end. Usually, the reference transmission power of the uplink user end is set to P _{O_Norminal_PUCCH} +PL, where PL is the path loss from the uplink user end to the base station. Although this parameter is used for the transmission power control of the uplink user end, in order to enable the D2D user end to set an appropriate D2D transmission power according to the transmission power of the uplink user end, the D2D user end also needs to obtain this parameter.

After obtaining the above power control parameters, the D2D UE can calculate the transmission power of the D2D UE in combination with the path loss PL between the D2D UE and the base station. According to the disclosed embodiments of the present invention, the power control formula (2) can be used:

P _D2D =min{P _CMAX,c ，P _{O_Norminal_PUCCH} +PL+Δ _D2D } (2) to calculate and obtain the transmission power of the D2D user end.

In another specific embodiment, step 304 further includes configuring a limited D2D transmission resource set, the limited D2D transmission resource set is composed of limited D2D transmission resources, and the limited D2D transmission resources are in the frequency domain, separated from The transmission resources used by the uplink user end for sending uplink information are relatively far away. The limited set of D2D transmission resources may be broadcast to the wireless network by the base station in step 304 .

In step 304, the base station broadcasts the configured power control parameters to the wireless network through system information or configuration information.

Specifically, in this step, the configured power control parameters are put into the system information or configuration information, and then the power control parameters are sent to the wireless network in the way of broadcasting, and the power control parameters located within the signal coverage of the base station The D2D UE can obtain the required power control parameters by receiving system information or configuration information broadcast by the base station. After obtaining the power control parameters, the D2D UE will set the corresponding D2D transmission power according to these parameters, and implement the transmission of D2D information.

In step 306, the base station measures the interference degree of the transmission signal sent by the D2D user terminal to the uplink signal of the uplink user terminal.

Specifically, the base station will measure the strength of the in-band interference generated by the D2D transmission signal on the base station side and the strength of the uplink signal sent by the uplink user end, so as to determine the interference degree of the in-band interference and whether the in-band interference It will affect the normal reception of the uplink signal by the base station.

In step 308, the base station adjusts part of the power control parameters according to the measurement result of the interference degree.

Specifically, a limit range of the interference degree may be set, and the upper limit of the range may represent: the maximum interference degree that the base station can bear without affecting the normal reception of the uplink signal sent by the uplink user terminal by the base station. The lower limit of the range may represent: when the base station normally receives the uplink signal sent by the uplink user terminal, the base station can ignore the maximum degree of interference.

In an example disclosed in the present invention, when the measurement result of the interference degree exceeds a predetermined limit range, the value of the D2D specific power control parameter _ΔD2D is reduced; so that the D2D transmission power is reduced to avoid D2D The transmission power affects the reception of the uplink signal sent by the uplink user terminal by the base station.

When the measurement result of the interference degree is lower than the predetermined limit range, increase the value of the D2D specific power control parameter _ΔD2D ; so that the D2D transmission power does not affect the base station receiving the uplink sent by the uplink user terminal Under the premise of the signal, obtain the largest possible value.

When the measurement result of the degree of interference is within the predetermined limit range, the value of the D2D specific power control parameter _ΔD2D is maintained.

The value of the D2D specific power control parameter _ΔD2D will be broadcast to the wireless network by the base station through system information or configuration information in step 310 .

However, even if the value of the D2D-specific power control parameter _ΔD2D is adjusted using the above method, although the interference from D2D transmissions is greatly reduced by D2D power control, it is still significantly larger than the interference of non-D2D subframes. Therefore, in order to ensure the quality of the PUCCH channel received by the base station side, the base station should properly adjust the power control parameters of the uplink user terminal.

According to an embodiment disclosed in the present invention, in order to avoid the internal influence of the power control of the uplink user terminal on the D2D power control, the dedicated PUCCH power control parameter P _O-UE-PUCCH is sent to the uplink user terminal through RRC signaling to further adjust the uplink user terminal. end transmission power. Usually, the base station configures the dedicated PUCCH power control parameter P _O-UE-PUCCH based on the measurement result of the in-band interference degree at the base station side. It should be noted that the dedicated PUCCH power control parameter P _O-UE-PUCCH is configured according to different uplink UEs.

In actual implementation, the relatively large value of the dedicated PUCCH power control parameter P _O-UE-PUCCH is configured in the initial stage of the D2D subframe, and in the subsequent sequence, based on the actual measurement value of the D2D subframe to update The dedicated PUCCH power control parameter P _O-UE-PUCCH . The dedicated PUCCH power control parameter P _O-UE-PUCCH is sent to each uplink UE through RRC signaling.

In step 310, broadcast the adjusted power control parameters to the wireless network through system information or configuration information.

Specifically, the base station puts the adjusted power control parameter, such as the D2D specific power control parameter Δ _D2D , into system information or configuration information, and then sends the power control parameter to the wireless network through broadcasting, The D2D UE located within the signal coverage of the base station can obtain the required power control parameters by receiving the system information or configuration information broadcast by the base station.

According to another embodiment disclosed in the present invention, after step 310 is completed, step 306 is repeatedly executed, so that steps 306 to 310 are repeatedly implemented in a loop, so as to continuously measure the impact of the transmission signal sent by the D2D UE on the The interference degree of the uploaded signal of the uplink user end, and adjust the power control parameter according to the interference degree.

In addition, in some implementation applications, for some purposes, the transmission power used by the D2D transmitter needs to be notified to the D2D receiver (for example, to realize the estimation of the neighbor distance). For this, according to another embodiment disclosed in the present invention, step 302 further includes: configuring a quantization set of transmission power P _D2D . In this way, based on a given transmission power set, the D2D transmission power used in open-loop power control can be quantized according to the quantization set, which can be predefined in the system specification or configured by the base station, and in step 304 broadcast to the wireless network through the base station in a semi-static manner. elements in the quantized set The corresponding relationship with the transmission power P _D2D is:

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0,1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; or</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Wherein, {P ₀ , P ₁ , ..., P _M-1 } is the quantization set of the transmission power P _D2D , and M is the number of elements in the quantization set.

Fig. 4 shows a flow chart of a method for controlling the transmission power P _D2D at the D2D user side according to the above disclosed solutions.

In step 402, periodically receive system information or configuration information broadcast by the base station, and obtain power control parameters therefrom.

Specifically, the D2D UE periodically obtains system information or configuration information broadcast by the base station, and obtains power control parameters: _ΔD2D , P _{O_Norminal_PUCCH} , and _{PCMAX, C} (these parameters have been introduced above and will not be repeated here. repeat).

According to another embodiment disclosed in the present invention, step 402 further includes obtaining the quantization set {P ₀ , P ₁ , . . . , P _M-1 } sent by the base station from the system information or configuration information.

In step 404, the D2D UE measures the path loss between itself and the base station. Various methods for measuring path loss in the prior art can be implemented in this method to obtain the path loss between the D2D UE and the base station, which will not be further discussed here.

In step 406, the D2D UE determines the transmission power P _D2D of the D2D UE according to the power control parameter and the path loss. According to an embodiment disclosed in the present invention, a method for calculating D2D transmission power P _D2D according to power control parameters and path loss is provided. That is, according to the formula:

P _D2D = min{P _{CMAX, c} , P _{O_Norminal_PUCCH} +PL+Δ _D2D } (2)

to calculate and obtain the transmission power of the D2D user end. Of course, the present invention is not limited to obtaining the transmission power of the D2D UE by using this formula. Other ways of obtaining the transmission power P _D2D of the D2D UE according to the power control parameters are also applicable to the present invention.

In step 408, the D2D UE performs quantization processing on the transmission power P _D2D determined in step 406 according to the quantization set obtained in step 402 or the quantization set predefined in the system to obtain the quantized D2D transmission power Described quantization process can realize according to formula (3):

${\stackrel{<span\; class="notranslate">\; ^</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0,1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; or</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In formula (3), if the transmission power value calculated according to the power control formula (2) is less than the minimum quantization power value P ₀ , then the actual applied transmission power value may be 0 or the minimum power value configured by each base station P ₀ .

In the previous example (the transmission power value is set to 0), it means that when a D2D user moves near the base station, so that the transmission power value calculated from the power control formula (2) is too low, which will make the D2D The UE cannot send D2D information, but can only receive D2D information from other D2D users.

In the latter case (when the transmission power P _D2D is less than P ₀ , then put It is set to the minimum quantization power value P ₀ ), which means that when a D2D user moves near the base station, the D2D user terminal is allowed to use the minimum transmission power P ₀ for D2D transmission. In order to reduce the potential in-band interference to the base station, it is recommended that the D2D UE can only use limited D2D resources (automatically selected or allocated by the base station) in some limited D2D resource sets. The PRB resources in the limited D2D resource set are relatively far from the PRB resources used by the PUCCH channel of the uplink UE in the frequency domain. It can be found from Fig. 1 that the in-band transmission interference adjacent to the physical resource blocks used by D2D is still relatively high. The configuration information of the limited D2D resource set can be broadcast to the wireless network through the base station in the system information together with other power control parameters.

Fig. 5 shows a flow chart of a method for controlling the transmission power of the uplink user end at the uplink user side according to the solution disclosed above.

In step 502, the uplink UE periodically receives system information or configuration information broadcast by the base station, and obtains power control parameters therefrom. The power control parameters include P _{O_Norminal_PUCCH} .

In step 504, the uplink UE judges whether the RRC signaling in the downlink channel includes the dedicated PUCCH power control parameter P _O-UE-PUCCH , and when the RRC signaling includes the dedicated PUCCH power control parameter P _O-UE-PUCCH , step 508 is implemented; when the dedicated PUCCH power control parameter P _O-UE-PUCCH is not included in the RRC signaling, step 506 is implemented.

In step 506, the uplink user terminal determines the transmission power of the uplink user terminal according to the common PUCCH power control parameter P _{O_Norminal_PUCCH} among the power control parameters.

In step 508, the uplink UE determines the transmission power of the uplink UE according to the common PUCCH power control parameter P _{O_Norminal_PUCCH} and the dedicated PUCCH power control parameter P _O-UE-PUCCH . That is, a PO _-UE-PUCCH is added on the basis of the original _{PO_Norminal_PUCCH} , so as to increase the transmission power of the uplink user terminal.

Next, a system-level simulation will be used to verify the effectiveness of the above scheme. Table-1 lists the main parameters of the simulation. Figures 6-8 show the simulation results.

Fig. 6 shows a schematic diagram of the cumulative distribution function (CDF) of the signal-to-interference-plus-noise ratio (SINR) on the PUCCH signal received at the base station side; in Fig. 6, we can find that when the D2D disclosed in the present invention is not implemented When the power control scheme is transmitted, approximately 30% of the received PUCCHs have a signal-to-interference-plus-noise ratio (SINR) lower than 5dB, however, after applying the power control scheme proposed by the present invention, almost all received All received PUCCHs have a signal-to-interference-plus-noise ratio (SINR) exceeding -5db. Therefore the potential impact of D2D transmission on PUCCH reception is basically avoided.

FIG. 7 shows a schematic diagram of Cumulative Distribution Function (CDF: Cumulative Distribution Function) of D2D transmission power with power control and without power control. From the figure, we can find that after the UEs use the transmission power control scheme disclosed in the present invention, more than 40% of the D2D UEs use a transmission power greater than 0 dBm.

One possible concern with using D2D transmission power control is that low power transmissions may have a negative impact on the operation of D2D transmissions (eg D2D neighbor discovery). Figure 8 shows the related simulation results. Fig. 8 shows a schematic diagram of the cumulative distribution function (CDF) of the number of neighbors found on the D2D receiver when power control is used and when power control is not used. The figure shows the cumulative distribution function (CDF) of the number of neighboring users discovered by each D2D discovery receiver in one discovery cycle. It can be seen from the figure that under the condition of power control, although the D2D transmission power is reduced, the number of neighbors found is only limited in the end. The reason is: although the useful signal power is reduced, on the other hand, the in-band interference from other D2D transmissions and PUCCH transmissions of uplink users is also reduced. Therefore, using the power control scheme disclosed in the present invention, the neighbor discovery performance degradation is very limited.

Table 1

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all respects as exemplary and not restrictive. Furthermore, it is obvious that the word "comprising" does not exclude other elements and steps, and the word "a" does not exclude the plural. A plurality of elements recited in device claims may also be embodied by one element. The words first, second, etc. are used to denote names and do not imply any particular order.

Claims (15)

1. Transmission power P for D2D user terminal at base station side_D2DThe D2D ue is located in the coverage of the base station, and the D2D ue and other uplink ues that need to send uplink information to the base station use uplink frequency resources in a wireless network in a frequency division multiplexing manner, wherein:

A. configuring power control parameters for the D2D ue and the uplink ue;

B. broadcasting the configured power control parameters to the wireless network through system information or configuration information;

C. measuring the interference degree of the transmission signal sent by the D2D user side to the uploading signal of the uplink user side;

D. adjusting part of the power control parameters according to the measurement result of the interference degree;

E. broadcasting the adjusted power control parameter to the wireless network via system information or configuration information.

2. The method of claim 1, wherein the power control parameter comprises:

a maximum transmission power parameter P of carriers configured for the D2D user terminal_CMAX，C；

Public PUCCH power control parameter P configured for uplink user terminal_{O_Norminal_PUCCH}；

D2D specific power control parameter delta configured for the D2D user terminal_D2D。

3. The method of claim 2, wherein, in said step D,

reducing the D2D specific power control parameter Δ when the measurement of the degree of interference exceeds a predetermined limit range_D2DA value of (d);

increasing the D2D specific power control parameter Δ when the measured interference level is below the predetermined limit range_D2DA value of (d);

maintaining the D2D-specific power control parameter Δ when the measure of the degree of interference is within the predetermined limit_D2DThe value of (c).

4. The method of claim 3, further comprising, in step A,

a1. presetting signal-to-noise ratio threshold gamma_PUCCHIt represents a critical value of the ratio of the uplink signal of the uplink ue to the in-band interference at the base station side, where the in-band interference is: the D2D client sendsInterference of the transmitted transmission signal on an uplink signal of an uplink user terminal;

a2. according to the signal-to-noise ratio threshold value gamma_PUCCHConfiguring the D2D specific power control parameter Δ_D2D。

5. The method of claim 4, wherein in step a 2: according to equation P_{O_Norminal_PUCCH}-(P_{O_Norminal_PUCCH}+Δ_D2D+10log₁₀(N_{PRB_D2D})-36)>γ_PUCCHConfiguring the D2D specific power control parameter Δ_D2DA value of (b), wherein said N_{PRB_D2D}The number of physical resource blocks used by the frequency domain where the D2D user terminal is located.

6. The method according to claim 3, wherein in step A, the D2D specific power control parameter Δ_D2DIs a value preset according to the transmission condition of the wireless network.

7. The method of claim 2 or 3,

in step D, when the measurement result of the interference degree exceeds a predetermined limit range, configuring a dedicated PUCCH power control parameter P for the uplink ue_O-UE-PUCCHBy the dedicated PUCCH power control parameter P_{O_UE_PUCCH}To increase the transmission power of the uplink ue.

8. The method of claim 7, further comprising:

configuring the transmission power P_D2DAnd broadcasting the quantized set into the wireless network, elements in the quantized setAnd the transmission power P_D2DThe corresponding relation is as follows:

<math> <mrow> <msub> <mover> <mi>P</mi> <mo>^</mo> </mover> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>=</mo> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> <mo>,</mo> </mtd> <mtd> <msub> <mi>P</mi> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>&GreaterEqual;</mo> <msub> <mi>P</mi> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mi>m</mi> </msub> <mo>,</mo> </mtd> <mtd> <msub> <mi>P</mi> <mrow> <mi>m</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> <mo>></mo> <msub> <mi>P</mi> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>&GreaterEqual;</mo> <msub> <mi>P</mi> <mi>m</mi> </msub> <mo>,</mo> <mi>m</mi> <mo>=</mo> <mn>0,1</mn> <mo>,</mo> <mo>.</mo> <mo>.</mo> <mo>.</mo> <mo>,</mo> <mi>M</mi> <mo>-</mo> <mn>2</mn> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> <mi>or</mi> <msub> <mi>P</mi> <mn>0</mn> </msub> <mo>,</mo> </mtd> <mtd> <msub> <mi>P</mi> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>&lt;</mo> <msub> <mi>P</mi> <mn>0</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </mrow> </math>

wherein, { P₀，P₁，...，P_M-1Is the transmission power P_D2DM is the number of elements in the quantization set.

9. The method of claim 8, wherein:

in the step a, configuring a defined D2D transmission resource set, where the defined D2D transmission resource set is composed of defined D2D transmission resources, and the defined D2D transmission resources are relatively far away from the transmission resources used by the uplink user terminals to transmit uplink information in the frequency domain;

in step B, broadcasting the defined set of D2D transmission resources into the wireless network via system information or configuration information.

10. Transmission power P for D2D user side at D2D user side_D2DThe D2D user end is located in the coverage of the base station, the D2D user end and other uplink user ends that need to send uplink information to the base station use the uplink frequency resources in the wireless network together in a frequency division multiplexing manner, wherein:

periodically receiving system information or configuration information broadcast by the base station and obtaining power control parameters from the system information or configuration information;

measuring a path loss PL from the base station;

determining the transmission power P of the D2D user terminal according to the power control parameter and the path loss_D2D。

11. The method of claim 10, wherein the power control parameter comprises:

a maximum transmission power parameter P of carriers configured for the D2D user terminal_CMAX，C；

Public PUCCH power control parameter P configured for uplink user terminal_{O_Norminal_PUCCH}；

D2D specific power control parameter delta configured for the D2D user terminal_D2D。

12. The method of claim 11, wherein, according to the formula:

P_D2D=min{P_CMAX，c，P_{O_Norminal_PUCCH}+PL+Δ_D2Ddetermine the transmission power P of the D2D user terminal_D2D。

13. The method of claim 12, further comprising:

receiving a quantization set { P) transmitted by the base station₀，P₁，...，P_M-1According to the formula:

<math> <mrow> <msub> <mover> <mi>P</mi> <mo>^</mo> </mover> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>=</mo> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> <mo>,</mo> </mtd> <mtd> <msub> <mi>P</mi> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>&GreaterEqual;</mo> <msub> <mi>P</mi> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mi>m</mi> </msub> <mo>,</mo> </mtd> <mtd> <msub> <mi>P</mi> <mrow> <mi>m</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> <mo>></mo> <msub> <mi>P</mi> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>&GreaterEqual;</mo> <msub> <mi>P</mi> <mi>m</mi> </msub> <mo>,</mo> <mi>m</mi> <mo>=</mo> <mn>0,1</mn> <mo>,</mo> <mo>.</mo> <mo>.</mo> <mo>.</mo> <mo>,</mo> <mi>M</mi> <mo>-</mo> <mn>2</mn> </mtd> </mtr> <mtr> <mtd> <mn>0</mn> <mi>or</mi> <msub> <mi>P</mi> <mn>0</mn> </msub> <mo>,</mo> </mtd> <mtd> <msub> <mi>P</mi> <mrow> <mi>D</mi> <mn>2</mn> <mi>D</mi> </mrow> </msub> <mo>&lt;</mo> <msub> <mi>P</mi> <mn>0</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </mrow> </math> transmission power P to the D2D user terminal_D2DPerforming quantization and quantizing the transmission powerAs the transmission power of the D2D ue, where M is the number of elements in the quantization set.

14. The method of claim 13, further comprising:

receiving system information or configuration information broadcast by the base station and obtaining therefrom a defined set of D2D transmission resources;

when the transmission power P of the D2D user terminal_D2DLess than the minimum quantization power P in the quantization set₀Using a defined D2D resource of the defined set of D2D transmission resources as a transmission resource for D2D transmissions;

wherein, in the frequency domain, the limited D2D transmission resource is relatively far away from the transmission resource used by the uplink user end for transmitting the uplink information.

15. A method for controlling transmission power of uplink ue at an uplink ue side, wherein the uplink ue is a ue that needs to send uplink information to a base station, a D2D ue is located within a coverage area of the base station, and the D2D ue and the uplink ue use uplink frequency resources in a wireless network in a frequency division multiplexing manner, wherein:

periodically receiving system information or configuration information broadcast by the base station and obtaining power control parameters from the system information or configuration information;

according to the common PUCCH power control parameter P in the power control parameters_{O_Norminal_PUCCH}Determining the transmission power of the uplink user terminal; wherein,

when acquiring the special PUCCH power control parameter P from the RRC signaling in the downlink channel of the uplink user terminal_O-UE-PUCCHThe method comprises the following steps: according to the power control parameter P of the public PUCCH_{O_Norminal_PUCCH}And the special PUCCH power control parameter P_O-UE-PUCCHAnd determining the transmission power of the uplink user terminal.