TWI594640B - A method for reducing the impact of D2D in-band interference on cellular transmission - Google Patents

Description

Method for reducing the influence of D2D in-band interference on cellular transmission

The present invention relates to the field of wireless communications, and more particularly to a method for reducing the impact of D2D in-band interference on cellular transmission in base stations and user equipment in a wireless communication system.

It has been determined in the study of LTE D2D that the D2D signal will occupy part of the uplink cellular resources (i.e., the uplink carrier for FDD and the uplink sub-frame for TDD), as in the case of FDD in Figure 2. In practice, the D2D signal will occupy some periodic uplink sub-frames in which the uplink cellular control signal (i.e., PUCCH) must still be transmitted in order to support normal downlink cellular transmission. That is, in the D2D sub-frame, the cellular PUCCH signal must be multiplexed with the D2D signal through FDM, as shown in Figure 2. On the other hand, the modeling of the in-band radiation interference is as described in "3GPP TR38.843 V12.0.1, "Study on LTE Device to Device Proximity Services-radio aspects"", the cellular PUCCH signal is subjected to D2D. In-band interference of the signal. One of the in-band radiation interference models is shown in Figure 1. An example.

Since the uplink PUCCH signal (ie, ACK/NACK, CQI feedback, etc. depending on the PUCCH format) plays a key role in supporting downlink data transmission, the in-band radiation interference from the D2D signal to the cellular control signal must be solve. The present invention aims to solve this technical problem.

FIG. 1 shows an example of in-band interference based on the modeling method described in "3GPP TR38.843 V12.0.1, "Study on LTE Device to Device Proximity Services-radio aspects"", in which the parameter is updated to { W, X, Y, Z} = {3, 6, 3, 3}.

The effects of in-band radiated interference of D2D signals on cellular signals have been extensively discussed in previous RAN1 (before RAN1-77) conferences. According to the schedule, this technical issue will be an important topic for the upcoming RAN1-77 meeting.

Up to now, the best solution to the problem of the prior art is to use power control for the D2D signal, which has been implemented in the Chinese patent application No. 201410041266.0 filed by the inventor of the present invention. The method of control is presented.

In-band radiation interference for uplink cellular signals is well controlled in this patent. However, there are also some shortcomings. The main disadvantage is that due to the use of power control, the D2D signal transmission power is different for different D2D users (the closer the D2D signal transmission power is used, the smaller the D2D signal transmission power is from the base station eNB), so the D2D transmission range is not same. This is not an ideal attribute for D2D transmission.

In accordance with the above-described prior art and prior art understanding, a first aspect of the present invention provides a method for reducing the impact of D2D in-band interference on cellular transmission in a base station in a wireless communication system, the method comprising the following Step: - the base station configures the D2D resource pool to include a resource pool of the first area and the second area, wherein the first area is a restricted D2D resource area and the second area is unrestricted D2D resource area.

The inventors of the present invention innovatively utilize a base station to configure a D2D resource pool as a resource pool including a first area and a second area, wherein the first area is a restricted D2D resource area and the second area is Unrestricted D2D resource area. In such a configuration, the D2D resource pool can be partitioned to configure it for different user equipments or to autonomously select different resource regions for use, thereby advantageously reducing the impact of D2D in-band interference on cellular transmission.

In an embodiment of the present invention, the number of resource blocks of the first area is smaller than the number of resource blocks of the second area, or the number of sub-frames of the first area is less than the number of sub-frames of the second area. .

The size of the first area and the second area can be configured in such a manner as to be able to meet the needs of different application scenarios in order to reduce the impact of D2D in-band interference on cellular transmission without affecting normal communication requirements.

In an embodiment in accordance with the invention, the method further includes Comprising: - dividing the D2D user equipment into at least two packets according to a predetermined rule, the at least two packets comprising a first packet and a second packet; and - the first packet is configured to only accept the first region Resources in the restricted D2D resource area are used for D2D communication, and the second packet is configured to be able to use resources in the unrestricted D2D resource area of the second area for D2D communication or to use the first area and the second Resources in the zone are used for D2D communication.

In such an embodiment, the user equipment is grouped by a base station, such an embodiment is merely exemplary and not limiting. It will be appreciated by those skilled in the art that such a packet can also determine which packet it belongs to by the user equipment, and can of course be divided into more than two packets for precise control. After grouping, the different resource pool partitions are configured by configuring different packets to optimize the impact of reducing D2D in-band interference on cellular transmission.

In an embodiment in accordance with the invention, the second packet is configured to be capable of using resources in the unrestricted D2D resource region of the second region for D2D communication. The configuration is such that the second packet is configured to be able to use resources in the unrestricted D2D resource region of the second region for D2D communication, such that the D2D user equipment of the second packet can be made to the PUCCH of the corresponding base station. That is, the impact of the reception of the physical uplink control channel is minimized.

In an embodiment according to the present invention, the predetermined rule includes: the base station according to a user equipment connected thereto to the base station The signal strength divides the user equipment connected thereto into at least two packets; or the base station divides the user equipment connected thereto into at least two packets according to the degree of interference of the base station with the user equipment connected thereto.

Those skilled in the art will appreciate that the above two modes are merely exemplary and not limiting, and other suitable grouping methods are also possible. Variations of the embodiments of the invention that conform to the main idea of the invention are intended to fall within the scope of the invention.

In an embodiment according to the present invention, the first packet is a set of user equipments that receive a signal strength of the base station that exceeds a first threshold, and the signal strength of the second packet that is received by the base station does not exceed a set of user equipment of the first threshold.

In this way, the respective user equipment can be advantageously and quickly grouped.

Furthermore, a second aspect of the present invention also provides a method for reducing the impact of D2D in-band interference on cellular transmission in a user equipment in a wireless communication system, the method comprising the steps of: - said user equipment according to The signal quality of the signal received by the base station with which it is communicated is determined by the first location state information associated with the user equipment; - the user equipment performs corresponding D2D resource selection according to the first location state information.

In the solution proposed by the second aspect of the present invention, the user equipment determines the first location state information associated with the user equipment according to the signal quality of the received signal, and then the user equipment according to the first location The status information is used to select the corresponding D2D resource. In this way, the user equipment can make an orderly selection of the D2D resources according to the first location state information, instead of controlling the D2D resource selection as in the prior art, only the disorder is selected.

In an embodiment of the present invention, the user equipment further receives configuration information of the resource pool from the base station, where the configuration information of the resource pool includes resource configuration information indicating the first area and the second area, The first area is a restricted D2D resource area and the second area is a non-restricted D2D resource area.

In this way, the user equipment can know how the corresponding base station allocates the D2D resource pool. According to the allocation mode, the user equipment according to the present invention can select the D2D resource accordingly to reduce the D2D in-band interference. Impact on cellular transmission.

In an embodiment according to the present invention, the first location status information has location status indication information including at least a first status and a second status, wherein the first status indicates that the user equipment is located at a cell center and The second state indicates that the user equipment is located at the edge of the cell. A grouping scheme is shown in such a way as to subsequently select the D2D resources.

In one embodiment in accordance with the invention, the user equipment located at the cell center uses the same transmit power as the user equipment located at the cell edge or the transmit power of the user equipment located at the cell center is less than the transmit power of the user equipment located at the cell edge.

Those skilled in the art should understand that the user set at the center of the cell The transmit power used in the standby can be the same as or different from the transmit power used by the user equipment located at the edge of the cell. Of course, the same transmit power can ensure that the D2D user equipment has substantially the same coverage when performing neighbor discovery, which is advantageous for neighbor discovery. However, the transmit power used by the user equipment located at the cell center and the transmit power used by the user equipment located at the edge of the cell can of course be different, for example, the transmit power of the user equipment located at the cell center is higher than the transmit power of the user equipment located at the edge of the cell. Small, in this way, the impact of user equipment at the center of the cell on cellular transmission can be further reduced.

In an embodiment in accordance with the invention, when the user equipment is located at a cell center, the user equipment is configured to use only resources in the restricted D2D resource area of the first area for D2D communication; When the user equipment is located at the edge of the cell, the user equipment is configured to be able to use resources in the unrestricted D2D resource area of the second area for D2D communication or to use resources in the first area and the second area for D2D Communication. In such an embodiment, the user equipment is grouped by the user equipment itself, such an embodiment is merely exemplary and not limiting. Those skilled in the art will appreciate that it is of course also possible to divide into more than two groups for precise control. After grouping, the different resource pool partitions are configured by configuring different packets to optimize the impact of reducing D2D in-band interference on cellular transmission.

In one embodiment in accordance with the invention, when the user equipment is located at the cell edge, the user equipment is configured to be able to use only resources in the unrestricted D2D resource area of the second area for D2D communication. Through this The configuration is such that the second packet is configured to be able to use the resources in the unrestricted D2D resource region of the second region for D2D communication, such that the D2D user equipment of the second packet can make the PUCCH of the corresponding base station The impact of the reception of the physical uplink control channel is minimized.

In an embodiment in accordance with the invention, when the user equipment is located at a cell edge and the user equipment is configured to be able to use resources in the restricted D2D resource area in the first area and the second area and unrestricted When the resources in the D2D resource area are used for D2D communication, the user equipment selects resources in the restricted D2D resource area of the first area for D2D communication with a first probability and selects the non-received area of the second area with a second probability Resources in the restricted D2D resource area are used for D2D communication. In an embodiment in accordance with the invention, the first probability is less than the second probability. In an embodiment in accordance with the invention, the first probability is associated with a quantity of resources of the first area and the second probability is associated with a quantity of resources of the second area.

The inventors of the present invention innovatively utilize a base station to configure a D2D resource pool as a resource pool including a first area and a second area, wherein the first area is a restricted D2D resource area and the second area is Unrestricted D2D resource area. In such a configuration, the D2D resource pool can be partitioned to configure it for different user equipments or to autonomously select different resource regions for use, thereby advantageously reducing the impact of D2D in-band interference on cellular transmission.

Other features, objects, and advantages of the invention will be apparent from the description of the appended claims.

1 shows a schematic diagram 100 of interference in the prior art due to signal power leakage; FIG. 2 shows a schematic diagram 200 of a configuration of a D2D resource pool in the prior art; FIG. 3 shows a D2D resource according to the present invention. Schematic diagram 300 of a configuration of a pool; FIG. 4 shows a schematic diagram 400 of a specific embodiment of a configuration of a D2D resource pool in accordance with the present invention; FIG. 5 illustrates a base station for use in a wireless communication system in accordance with the present invention. Flowchart 500 of a method for reducing the impact of D2D in-band interference on cellular transmission; and FIG. 6 illustrates a method for reducing D2D in-band interference to cellular transmission in a user equipment in a wireless communication system in accordance with the present invention. Flowchart 600 of the method of influence.

Throughout the drawings, the same or similar reference numerals indicate the same or similar devices (module) or steps.

In the detailed description of the preferred embodiments that follow, reference is made to the accompanying drawings that form a part of the invention. The accompanying drawings illustrate, by way of example, specific embodiments Example embodiments are not intended All embodiments in accordance with the present invention are exhausted. It is to be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of the invention. Therefore, the following detailed description is not to be considered as limiting

FIG. 1 shows a schematic diagram 100 of prior art interference due to signal power leakage. As can be seen from FIG. 1, when the useful signal 1 is transmitted, it will cause carrier leakage identified by 2, thereby affecting the progress of other cellular communications. On the other hand, FIG. 2 shows a schematic diagram 200 of a configuration of a D2D resource pool in the prior art. As can be seen from Figure 2, the PUCCH of the cellular network as an important signal of the control channel must be transmitted in the uplink resource, so that the PUCCH of the cellular network must be frequency-multiplexed with the uplink frame of the D2D, due to The presence of the carrier leakage illustrated in Figure 1 would necessarily result in uncontrolled interference with the reception of the PUCCH.

In order to reduce such interference, the present invention proposes a solution which aims to largely solve the in-band interference of the D2D signal with respect to the cellular signal. The main idea of the invention is as follows:

If the D2D transmission uses a constant (and relatively large, for example 23 dBm) transmission power, the base station eNB will experience multiple in-band interference in decoding the uplink signal (e.g., PUCCH), as previously described. If further details are considered from the D2D signal to the PUCCH reception, most of the interference in such interference is the D2D user equipment UEs that are closer to the base station eNB. The inventors of the present invention have drawn an enlightenment to arrange a special area in the configured D2D sub-frame (immediately In addition, the D2D user in the cell center can occupy only the resources in the special area, while other D2D users can occupy any resources in the configured resource pool, or alternatively, other D2D users are better. The resources outside the special area are occupied to reduce the collision with the D2D user equipment UE of the cell center. Here, the special resource area is referred to as a restricted D2D resource area. 3 shows a schematic diagram 300 of a configuration of a D2D resource pool in accordance with the present invention. This configuration is shown in Figure 3. As can be seen from FIG. 3, the inventors of the present invention innovatively utilize a base station to configure a D2D resource pool as a resource pool including a first area and a second area, wherein the first area is a restricted D2D resource area and the The second area is an unrestricted D2D resource area. In such a configuration, the D2D resource pool can be partitioned to configure it for different user equipments or to autonomously select different resource regions for use, thereby advantageously reducing the impact of D2D in-band interference on cellular transmission.

3 is only schematic, not specifically sized for each region, and FIG. 4 shows a schematic diagram 400 of one embodiment of a configuration of a D2D resource pool in accordance with the present invention. It is assumed that the D2D resource pool is configured by the base station eNB as a periodically consecutive uplink sub-frame having the following sizes, that is, 44 PRBs in the frequency domain and 32 sub-frames in the time domain, as shown in FIG. . Those skilled in the art will appreciate that these parameter values are merely exemplary and not limiting. Under the resource configuration as shown in FIG. 4, in order to address possible in-band interference of D2D signals for PUCCH reception, the present invention proposes to configure a restricted area in the D2D resource pool. The size of this restricted area should be very limited. As shown in the example in Figure 4.

Next, the effect of reducing D2D in-band interference on cellular transmission in a base station and a user equipment in a wireless communication system with the resource pool allocation shown in FIG. 3 will be respectively described with the aid of FIG. 5 and FIG. Flowcharts of methods 500 and 600.

5 shows a flow diagram 500 of a method for reducing the impact of D2D in-band interference on cellular transmissions in a base station in a wireless communication system in accordance with the present invention. The method according to FIG. 5 includes at least the following steps: in method step 510, the base station configures the D2D resource pool to include a resource pool of the first area and the second area, wherein the first area is restricted The D2D resource area and the second area is an unrestricted D2D resource area.

Preferably, in an embodiment of the present invention, the number of resource blocks of the first area is smaller than the number of resource blocks of the second area or the number of sub-frames of the first area is smaller than the number of sub-frames of the second area.

The size of the first area and the second area can be configured in such a manner as to be able to meet the needs of different application scenarios in order to reduce the impact of D2D in-band interference on cellular transmission without affecting normal communication requirements.

Preferably, in an embodiment in accordance with the invention, the method further comprises: - dividing the D2D user equipment into at least two packets according to a predetermined rule, the at least two packets comprising the first packet and the second packet; and - A packet is configured to only limit the D2D of the first region Resources in the resource area are used for D2D communication, and the second packet is configured to be able to use resources in the unrestricted D2D resource area of the second area for D2D communication or to use resources in the first area and the second area For D2D communication.

Preferably, in such an embodiment, the user equipment is grouped by a base station, such an embodiment is merely exemplary and not limiting. It will be appreciated by those skilled in the art that such a packet can also determine which packet it belongs to by the user equipment, and can of course be divided into more than two packets for precise control. After grouping, the different resource pool partitions are configured by configuring different packets to optimize the impact of reducing D2D in-band interference on cellular transmission.

Preferably, in an embodiment in accordance with the invention, the second packet is configured to be capable of using resources in the unrestricted D2D resource region of the second region for D2D communication. The configuration is such that the second packet is configured to be able to use resources in the unrestricted D2D resource region of the second region for D2D communication, such that the D2D user equipment of the second packet can be made to the PUCCH of the corresponding base station. That is, the impact of the reception of the physical uplink control channel is minimized.

Preferably, in an embodiment according to the present invention, the predetermined rule includes: the base station divides the user equipment connected thereto according to the signal strength of the user equipment connected thereto to the base station into at least two groups; or the base station according to the base The degree of interference of the station with the user equipment connected to it is divided into at least two groups of user equipment connected thereto.

Those skilled in the art will appreciate that the above two modes are merely exemplary and not limiting, and other suitable grouping methods are also possible. Variations of the embodiments of the invention that conform to the main idea of the invention are intended to fall within the scope of the invention.

Preferably, in an embodiment according to the present invention, the first packet is a set of user equipments whose receiving base station has a signal strength exceeding a first threshold and the second packet is a signal strength of the receiving base station does not exceed a first threshold. A collection of user devices. In this way, the respective user equipment can be advantageously and quickly grouped.

6 shows a flow diagram 600 of a method for reducing the impact of D2D in-band interference on cellular transmissions in user equipment in a wireless communication system in accordance with the present invention. As can be seen from FIG. 6, the method according to the invention has at least the following two steps: in method step 610, the user equipment determines the number associated with the user equipment based on the signal quality of the signal received from the base station with which it is communicating. A location status information; then, in method step 620, the user equipment performs a corresponding D2D resource selection based on the first location status information.

In the solution shown in FIG. 6 according to the present invention, the user equipment determines the first location state information associated with the user equipment according to the signal quality of the received signal, and then the user equipment performs corresponding according to the first location state information. D2D resource selection. In this way, the user equipment can make an orderly selection of the D2D resources according to the first location state information, instead of controlling the D2D resource selection as in the prior art, only the disorder is selected.

Preferably, in an embodiment of the present invention, the user equipment further receives the configuration information of the resource pool from the base station, where the configuration information of the resource pool includes resource configuration information indicating the first area and the second area, where The first area is a restricted D2D resource area and the second area is an unrestricted D2D resource area.

In this way, the user equipment can know how the corresponding base station allocates the D2D resource pool. According to the allocation mode, the user equipment according to the present invention can select the D2D resource accordingly to reduce the D2D in-band interference. Impact on cellular transmission.

Preferably, in an embodiment according to the present invention, the first location state information has location state indication information including at least a first state and a second state, wherein the first state indicates that the user equipment is located at the cell center and the second state Indicates that the user device is at the edge of the cell. A grouping scheme is shown in such a way as to subsequently select the D2D resources.

Preferably, in an embodiment in accordance with the invention, the user equipment located at the cell center uses the same transmission power as the user equipment located at the cell edge or the transmission power of the user equipment located at the cell center is higher than that of the user equipment located at the edge of the cell. The transmission power is small.

Those skilled in the art will appreciate that the transmit power used by the user equipment at the cell center can be the same as or different from the transmit power used by the user equipment located at the cell edge. Of course, the same transmit power can ensure that the D2D user equipment has substantially the same coverage when performing neighbor discovery, which is advantageous for neighbor discovery. However, the transmit power used by the user equipment at the cell center is used by the user equipment at the edge of the cell. The transmit power can of course be different, for example, the user equipment at the cell center has a lower transmit power than the user equipment at the cell edge, in such a way that the user equipment at the cell center can be further reduced for cellular transmission. influences.

Preferably, in an embodiment in accordance with the invention, when the user equipment is located at the cell center, the user equipment is configured to only use resources in the restricted D2D resource area of the first area for D2D communication; When the device is at the edge of the cell, the user equipment is configured to be able to use resources in the unrestricted D2D resource region of the second region for D2D communication or to use resources in the first region and the second region for D2D communication. In such an embodiment, the user equipment is grouped by the user equipment itself, such an embodiment is merely exemplary and not limiting. Those skilled in the art will appreciate that it is of course also possible to divide into more than two groups for precise control. After grouping, the different resource pool partitions are configured by configuring different packets to optimize the impact of reducing D2D in-band interference on cellular transmission.

Preferably, in one embodiment in accordance with the invention, when the user equipment is located at the edge of the cell, the user equipment is configured to only use resources in the unrestricted D2D resource area of the second area for D2D communication. The configuration is such that the second packet is configured to be able to use resources in the unrestricted D2D resource region of the second region for D2D communication, such that the D2D user equipment of the second packet can be made to the PUCCH of the corresponding base station. That is, the impact of the reception of the physical uplink control channel is minimized.

Preferably, in an embodiment in accordance with the invention, when the user equipment Located at the cell edge and the user equipment is configured to use resources in the restricted D2D resource area in the first area and the second area and resources in the unrestricted D2D resource area for D2D communication, the user equipment is first The probability selects resources in the restricted D2D resource region of the first region for D2D communication and selects resources in the non-restricted D2D resource region of the second region for D2D communication with a second probability. In an embodiment in accordance with the invention, the first probability is less than the second probability. In an embodiment in accordance with the invention, the first probability is associated with a quantity of resources of the first area and the second probability is associated with a quantity of resources of the second area.

The inventors of the present invention innovatively utilize a base station to configure a D2D resource pool as a resource pool including a first region and a second region, wherein the first region is a restricted D2D resource region and the second region is unrestricted D2D resource area. In such a configuration, the D2D resource pool can be partitioned to configure it for different user equipments or to autonomously select different resource regions for use, thereby advantageously reducing the impact of D2D in-band interference on cellular transmission.

It is apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments are to be considered as illustrative and not limiting in any way. In addition, 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 the device claims can also be implemented by one element. The first, second, etc. words are used to denote names and do not denote any particular order.

Claims (13)

A method for reducing the impact of D2D in-band interference on cellular transmission in a base station in a wireless communication system, the method comprising the steps of: - the base station configuring the D2D resource pool to include a first area and a second area Resource pool, wherein the first area is a restricted D2D resource area and the second area is a non-restricted D2D resource area; - dividing the D2D user equipment into at least two packets according to a predetermined rule, At least two packets include a first packet and a second packet; and - the first packet is configured to only use resources in the restricted D2D resource region of the first region for D2D communication, and the second packet The resources in the unrestricted D2D resource region of the second region are configured to be selected for D2D communication or to use resources in the first region and the second region for D2D communication. The method of claim 1, wherein the number of resource blocks of the first area is smaller than the number of resource blocks of the second area or the number of sub-frames of the first area is less than the second area. The number of sub-frames. The method of claim 1, wherein the second packet is configured to be capable of using resources in a non-restricted D2D resource region of the second region for D2D communication. The method of claim 1, wherein the predetermined rule comprises: the base station divides the user equipment connected thereto according to the signal strength of the user equipment connected thereto to the base station into at least two groups. ;or The base station divides the user equipment connected thereto into at least two groups according to the degree of interference of the base station with the user equipment connected thereto. The method of claim 1, wherein the first packet is a set of user equipments that receive a signal strength of the base station that exceeds a first threshold and the second packet is a base station that receives the base station. A set of user equipment whose signal strength does not exceed the first threshold. A method for reducing the impact of D2D in-band interference on cellular transmission in a user equipment in a wireless communication system, the method comprising the steps of: - a signal of the user equipment according to a signal received from a base station in communication therewith The quality is determined by the first location status information associated with the user equipment; the user equipment performs corresponding D2D resource selection according to the first location status information, where the user equipment further receives resources from the base station The configuration information of the pool, where the configuration information of the resource pool includes resource configuration information indicating the first area and the second area, where the first area is a restricted D2D resource area and the second area is non- a restricted D2D resource area, wherein the corresponding D2D resource selection according to the first location status information is only capable of using resources in the restricted D2D resource area of the first area for D2D communication, or can be selected for use Resources in the unrestricted D2D resource area of the second region are used for D2D communication or Resources in the first region and the second region are used for D2D communication. The method of claim 6, wherein the first location status information has location status indication information including at least a first status and a second status, wherein the first status indicates that the user equipment is located The cell center and the second state indicates that the user device is at the edge of the cell. The method of claim 7, wherein the user equipment located at the cell center uses the same transmission power as the user equipment located at the cell edge or the transmission power of the user equipment located at the cell center is greater than the user equipment located at the edge of the cell The transmission power is small. The method of claim 7, wherein when the user equipment is located at a cell center, the user equipment is configured to use only resources in the restricted D2D resource area of the first area for D2D Communication; when the user equipment is located at a cell edge, the user equipment is configured to be able to use resources in a non-restricted D2D resource area of the second area for D2D communication or to use in the first area and the second area Resources are used for D2D communication. The method of claim 9, wherein the user equipment is configured to use only resources in the unrestricted D2D resource area of the second area for D2D when the user equipment is located at a cell edge Communication. The method of claim 9, wherein the user equipment is located at a cell edge and the user equipment is configured to use a resource in a restricted D2D resource area in the first area and the second area. When the source and the resources in the unrestricted D2D resource region are used for D2D communication, the user equipment selects resources in the restricted D2D resource region of the first region for D2D communication with a first probability and selects with a second probability Resources in the unrestricted D2D resource area of the second region are used for D2D communication. The method of claim 10, wherein the first probability is less than the second probability. The method of claim 11, wherein the first probability is associated with a quantity of resources of the first area and the second probability is associated with a quantity of resources of the second area.