WO2015131493A1

WO2015131493A1 - Device discovering method and device discovering apparatus for d2d communication

Info

Publication number: WO2015131493A1
Application number: PCT/CN2014/084318
Authority: WO
Inventors: 郭胜祥
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-03-06
Filing date: 2014-08-13
Publication date: 2015-09-11
Also published as: CN104902455A

Abstract

The present invention provides a device discovering method and a device discovering apparatus for device-to-device (D2D) communication, which are used for mobile communication terminals. The method includes: a receiving step, namely selecting a device discovery sub frame and receiving signals of all resource units by the use of the device discovery sub frame in a device discovery cycle; a determining step, namely determining interference parameters for each resource unit; a judging step, namely judging whether there is a resource unit set the degree of interference of which is less than the interference parameters of a first resource unit and obtaining a judgment result; and a first performing step, when the judgment result indicates a resource unit set of which the degree of interference is less than the interference parameters of the first resource unit exists，a second resource unit is selected, from the resource unit set, as the resource unit of the next launch probe signals. By the present invention, the problem that the device discovery success rate is low due to signal interferences and signal collisions in the discovery process of the D2D device is solved, and the candidate resources are rationally allocated, and the D2D device discovery success rate is increased.

Description

The present invention relates to the field of wireless communications, and in particular, to a device discovery method and apparatus for D2D communication. Background Art In order to make full use of existing spectrum resources, the Third Generation Partnership Project (Third Generation Partnership)

Projects, referred to as 3GPP), proposed a device-to-device (D2D) direct communication technology. The technology utilizes direct communication between users in close proximity to one another without the involvement of base stations in traditional communication networks. And the D2D communication user can improve the spectrum utilization by sharing resources with the cell user. In addition, it can reduce the burden on cellular networks, reduce battery power consumption of mobile terminals, increase bit rate, improve the robustness of network infrastructure failures, and support new small-scale peer-to-peer data services. In addition, D2D communication is also in response to the needs of the public safety field. In the event of a major natural disaster, such as earthquakes and flash floods, it will often cause devastating damage to the existing deployed cellular communication network. The disappearance of the cellular network signal makes the mobile terminal unable to carry out the necessary communication, which brings great disaster relief. Difficulty. D2D communication technology can avoid this situation. In the absence of cellular network signals, direct communication between terminals can be realized, which will bring great convenience to disaster relief.

An important technology and premise of D2D communication is the mutual discovery process between D2D user equipments, that is, the D2D device discovery process. One consideration is that the cellular network completes its device discovery process by assigning a dedicated probe resource to each D2D user. The disadvantage of this method is that the cellular network is heavily burdened and needs to ensure that the probe resources cannot be interfered during the device discovery period. And more importantly, this method is not suitable for non-cellular networks. Another consideration is: To configure or preset candidate resources for all D2D devices, the D2D user randomly selects the required probe resources from the candidate resources to complete the device discovery process. This approach reduces or does not require network side involvement and is therefore also suitable for non-cellular network conditions. However, the disadvantage is that when multiple D2D users perform D2D device discovery, the selected probe resources may collide because the probe resources are randomly selected. Moreover, the in-band adjacent channel radiation signals of nearby cellular users may also interfere due to the near-far effect. To the selected probe resource, the device discovery success rate is low. Therefore, it is necessary to study a method to solve the problem, thereby improving the probability of success of D2D communication device discovery. SUMMARY OF THE INVENTION Embodiments of the present invention provide a device discovery method and device for D2D communication, so as to at least solve the problem that the device discovery success rate caused by signal interference and collision occurring in the D2D device discovery process in the prior art is reasonable. Utilize resources for device discovery. In order to solve the above problems, the present invention provides a device discovery method for D2D communication, which is used in a mobile communication terminal, and the mobile communication terminal can transmit a sounding signal for device discovery by using a resource unit in a candidate resource set, the device The discovery method includes: a receiving step, selecting a device discovery subframe in the device discovery period, and using the selected device discovery subframe to receive signals on all resource units; determining steps, determining interference parameters on each resource unit The interference parameter reflects the interference degree of the signal on the newly added detection signal in the corresponding resource unit; the determining step, according to the interference parameter, determining whether there is a resource whose interference degree is smaller than the interference parameter of the first resource unit a unit set, a judgment result, where the first resource unit is a resource unit that the mobile communication terminal transmits a sounding signal at a time; and a first performing step, the determining result indicates that the interference level is greater than the first resource unit When the interference parameter is small, the resource unit is collected, The second resource unit is selected as the resource unit of the next transmission detection signal. Preferably, the interference parameter is power on the resource unit, and the higher the power on the resource unit, the larger the interference parameter on the resource unit. Advantageously, said signal comprises all sounding signals occupying said resource unit; said power comprising power of said all sounding signals occupying said resource unit. Advantageously, the signal further comprises an interference signal occupying the resource unit; the power further comprising power of the interference signal occupying the resource unit. Preferably, the device discovery method further includes: a second performing step, when the determining result indicates that there is no resource unit set having a smaller interference level than the interference parameter of the first resource unit, still using the first resource The unit is the resource unit for the next transmission of the sounding signal. Preferably, the receiving step is specifically: selecting, in a device discovery period, a device discovery subframe in each κ device discovery subframe connection, as a device discovery subframe that receives signals on all resource units, and The selected frame discovery subframe receives signals on all resource units, where K is an integer greater than or equal to two. The present invention also provides a device discovery apparatus for D2D communication, which is used in a mobile communication terminal, and the mobile communication terminal is capable of transmitting a sounding signal for device discovery by using a resource unit in a candidate resource set, the device discovery apparatus comprising: receiving a module, in a device discovery period, selecting a device discovery subframe, and using the selected device discovery subframe to receive signals on all resource units; determining a module, determining interference parameters on each resource unit, the interference parameter Determining the degree of interference of the signal on the corresponding resource unit to the newly added detection signal; the determining module, according to the interference parameter, determining whether there is a resource unit set having a smaller interference level than the interference parameter of the first resource unit, acquiring one a judgment result, the first resource unit is a resource unit that the mobile communication terminal transmits a sounding signal at a time; the first execution module indicates, in the determination result, that the interference level is greater than the interference parameter of the first resource unit When a small resource unit is aggregated, from the resource unit set Optional second resource unit as a unit of transmission resources for the next probe signal. Preferably, the interference parameter is power on the resource unit, and the higher the power on the resource unit, the larger the interference parameter on the resource unit. Preferably, the device discovery device further includes: a second execution module, when the determination result indicates that there is no resource unit set that is less than the interference parameter of the first resource unit, the first resource is still The unit is the resource unit for the next transmission of the sounding signal. The device discovery method and device for D2D communication of the present invention solves the low success rate of device discovery caused by signal interference and collision in the process of discovering D2D devices by searching for resource units with small interference parameters as resources for transmitting detection signals. The problem is that reasonable allocation of candidate resources increases the success rate of D2D device discovery. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic flowchart diagram of a device discovery method for D2D communication according to an embodiment of the present invention; 2 is a schematic structural diagram of a device discovery device for D2D communication according to an embodiment of the present invention; FIG. 3 is another schematic flowchart of a device discovery method for D2D communication according to an embodiment of the present invention; A schematic diagram of a device discovery cycle. DETAILED DESCRIPTION OF THE EMBODIMENTS In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly, the following detailed description will be made with reference to the accompanying drawings and specific embodiments. FIG. 1 is a schematic flowchart diagram of a device discovery method for D2D communication according to an embodiment of the present invention. As shown in FIG. 1 , the present invention provides a device discovery method for D2D communication, which is used in a mobile communication terminal, and the mobile communication terminal can transmit a sounding signal for device discovery by using a resource unit in a candidate resource set, where the device The method includes: receiving step 101, selecting a device discovery subframe in the device discovery period, and using the selected device discovery subframe to receive signals on all resource units; determining step 102, determining each resource unit An interference parameter, where the interference parameter reflects the interference degree of the signal on the newly added detection signal in the corresponding resource unit; and determining step 103, determining, according to the interference parameter, whether the interference level is greater than the interference parameter of the first resource unit a small resource unit set, obtaining a judgment result, where the first resource unit is a resource unit that the mobile communication terminal transmits a sounding signal at a time; first performing step 104, indicating that the interference level is greater than the When the first resource unit has a small set of resource units of the interference parameter, Said selecting a second set of resource units as the resource units for the next resource unit emits an interrogation signal. The device discovery method of the D2D communication in the foregoing embodiment is performed by comparing the interference parameter indicating the degree of interference on the resource unit of the current detection signal with the interference parameter on the remaining resource units during the device discovery period. The resource unit with a small interference parameter is used as a resource unit for transmitting the detection signal next time. In this way, the problem that the device discovery success rate is low due to signal interference and collision during the discovery process of the D2D device is solved, the candidate resources are allocated reasonably, and the success rate of the D2D device discovery is increased. Preferably, the interference parameter may be power on the resource unit, and the higher the power on the resource unit, the larger the interference parameter on the resource unit. It is very convenient to use power as a parameter to measure the degree of interference on the resource unit, and can be implemented by a Received Signal Strength Indication (RSSI) technology. Advantageously, said signal comprises all sounding signals occupying said resource unit; said power comprising power of said all sounding signals occupying said resource unit. The D2D device discovery process is implemented by transmitting a sounding signal on a resource unit. The lower the power of the sounding signal occupying the resource unit is, the smaller the interference received by the resource unit is, the more suitable the resource unit is to transmit the sounding signal. Resources, the higher the success rate of device discovery. Of course, the interference of the resource unit is only derived from the detection signal occupying it. In an actual situation, the interference on the resource unit may come from multiple parties. Advantageously, the signal further comprises an interference signal occupying the resource unit; the power further comprising power of the interference signal occupying the resource unit. The interference signal may come from the interference of the user of the cellular network, or may be caused by the interference of the communication between the users of the D2D itself. Taking the interference source on the resource unit as a whole, the power measurement can be more accurate and more realistic. The resource unit thus found that can transmit the next detection signal is more accurate, and the success rate found by the D2D device is also higher. Preferably, the device discovery method further includes: a second performing step, when the determining result indicates that there is no resource unit set having a smaller interference level than the interference parameter of the first resource unit, still using the first resource The unit is the resource unit for the next transmission of the sounding signal. During the device discovery period, when a more suitable resource unit for transmitting the probe signal is not found, the probe signal is continuously transmitted in the original resource unit to continue the device discovery process. The D2D user in the embodiment of the present invention is a time division duplex user, that is, a D2D user in a device discovery subframe may only be in a state of transmitting a detection signal or accepting a detection signal, so that the process of receiving and transmitting is not performed. The receiving step 101 is specifically: selecting, in the device discovery period, a device discovery subframe in each K device discovery subframe connection, as a device discovery subframe that receives signals on all resource units. And using the selected device discovery subframe to receive signals on all resource units, where K is an integer greater than or equal to 2. The above embodiments are merely preferred embodiments of the present invention, and other variations and modifications of the various embodiments described above are considered to be within the scope of the present invention. FIG. 2 is a schematic structural diagram of a device discovery apparatus for D2D communication according to an embodiment of the present invention. As shown in FIG. 2, the present invention further provides a device discovery apparatus for D2D communication, which is used in a mobile communication terminal, and the mobile communication terminal is capable of transmitting a sounding signal for device discovery by using a resource unit in a candidate resource set, The device discovery device includes: a receiving module, in the device discovery period, selecting a device discovery subframe, and using the selected device discovery subframe to receive signals on all resource units; determining a module, determining interference on each resource unit a parameter, the interference parameter reflects an interference degree of the signal on the corresponding resource unit to the newly added detection signal; the determining module determines, according to the interference parameter, whether the interference level is smaller than the interference parameter of the first resource unit a set of resource units, obtaining a judgment result, where the first resource unit is a resource unit that the mobile communication terminal transmits a sounding signal at a time; the first execution module, indicating that the interference level is greater than the first resource When the unit of the interference parameter is small, the resource unit is collected from the resource Selecting a second set of resource unit as a unit of the next resource unit emits an interrogation signal. Preferably, the interference parameter is power on the resource unit, and the higher the power on the resource unit, the larger the interference parameter on the resource unit. Preferably, the device discovery device further includes: a second execution module, when the determination result indicates that there is no resource unit set that is less than the interference parameter of the first resource unit, the first resource is still The unit is the resource unit for the next transmission of the sounding signal. Specifically, the device discovery device of the D2D communication in the embodiment, by using the configuration of each module, finds a resource unit with a relatively small interference parameter as a resource unit for transmitting a sounding signal, and allocates resources reasonably, thereby reducing signal interference. The problem of low success rate of equipment discovery caused by collision. FIG. 3 is another schematic flowchart of a device discovery method for D2D communication according to an embodiment of the present invention. As shown in FIG. 3, the device discovery method for D2D communication provided in this embodiment is used for a mobile communication terminal, and the mobile communication terminal can transmit a sounding signal for device discovery by using a resource unit in a candidate resource set, the D2D The device discovery method for communication specifically includes: Receiving step 201, in the device discovery period, selecting a device discovery subframe in each K device discovery subframe connection, and using the device discovery subframe to receive signals on all resource units, where K is an integer greater than or equal to 2. . 4 is a schematic diagram of a device discovery cycle according to an embodiment of the present invention. As shown in FIG. 3 and FIG. 4, a device discovery period is composed of multiple device discovery subframes, and each device discovery subframe includes a cellular network user resource and a candidate resource for device discovery for D2D communication. The number of sub-frames discovered by the device during a device discovery period; the size of the sub-frames discovered by each device; and the amount of candidate resources discovered by the device for D2D communication, which may be preset in the mobile communication terminal, or may be The network side is configured and all D2D users are notified by broadcast information. For a Long-Term Evolution (LTE) system, each device discovery subframe may be a single 1 ms subframe of the LTE system, or may be composed of multiple LTE system single subframes. The candidate resource amount in each device discovery subframe may be given in the form of a Resource Block (RB) in the LTE system, for example, a candidate for device discovery for D2D communication in each device discovery subframe. The resource is 44 RBs. The resource unit refers to a candidate resource occupied by a single D2D user transmitting a sounding signal. For example: A resource unit can be a resource block occupying 2 LTE systems. The size of the resource units occupied by different D2D users may be the same or different. The candidate resource is a resource that all D2D users can use in a device discovery cycle, and is not a resource exclusive to a D2D user. The D2D user can select the required resource unit from the device discovery. The value of K in the receiving step 201 may be preset by the mobile communication terminal or may be specified by the cellular network side. Considering that the D2D user in this embodiment is a time division duplex user, the K value range is limited to an integer greater than or equal to 2, so that the selected device discovery subframe for receiving signals on all resource units is selected. Available. In particular, the signals on all of the received resource units include not only signals on other resource units, but also signals on resource units that transmit the sounding signals. The signal includes all sounding signals and interference signals occupying the resource unit. Step 202 is determined to determine the power on each resource unit. Specifically, the power on each resource unit is determined according to the received signal strength on each of the resource units. The power includes power of the all sounding signals occupying the resource unit and power of the interference signal. In step 203, it is determined whether there is a resource unit set whose power is lower than the power of the first resource unit by X dB, and a judgment result is obtained, where the first resource unit is a resource unit that the mobile communication terminal transmits the sounding signal this time; The power level on a resource unit reflects the degree of interference received by the resource unit. The higher the power in the resource unit, the greater the interference received by the resource unit, and the weaker the transmission capability; otherwise, the resource unit The lower the power, the smaller the interference that the resource unit is subjected to, and the stronger its transmitting capability. In this embodiment, the value of the value of X may be preset by the mobile communication terminal, or may be configured by the cellular network side. For example, X may be configured to be 6 dB. The determining step 203 is intended to find out whether there is a resource unit set of resource units whose transmission capability is better than that of the current transmission sounding signal. In a first execution step 204, when the determination result indicates that there is a resource unit set whose power is lower than the power of the first resource unit by XdB, the second resource unit is selected from the resource unit set as the next transmission detection. The resource unit of the signal. The second execution module 205, when the determination result indicates that there is no resource unit set whose power is lower than the power of the first resource unit by X dB, still uses the first resource unit as a resource unit of the next transmission detection signal. The resource unit whose transmission capability is better than or equal to the current detection signal is found in steps 204 and 205 as a resource for transmitting the detection signal next time. During a device discovery cycle, the process of step 201 205 is repeated until the device discovery cycle ends. In this way, not only the candidate resources are allocated reasonably, but also the problem of low success rate of device discovery caused by signal interference and collision is reduced. The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention. INDUSTRIAL APPLICABILITY As described above, a device discovery method and apparatus for D2D communication provided by an embodiment of the present invention have the following beneficial effects: The discovery of a D2D device is found by finding a resource unit having a small interference parameter as a resource for transmitting a detection signal. In the process, due to signal interference and collision, the success rate of device discovery is low, and the candidate resources are allocated reasonably, which increases the success rate of D2D device discovery.

Claims

Claim

A device discovery method for D2D communication, which is used in a mobile communication terminal, wherein the mobile communication terminal can transmit a sounding signal for device discovery by using a resource unit in a candidate resource set, and the device discovery method includes:

Receiving, in a device discovery period, selecting a device discovery subframe, and using the selected device discovery subframe to receive signals on all resource units;

Determining a step of determining an interference parameter on each resource unit, the interference parameter reflecting an interference degree of the signal on the corresponding resource unit to the newly added detection signal; and determining, according to the interference parameter, determining whether there is interference ratio a set of resource units having a small interference parameter of the first resource unit, and obtaining a determination result, where the first resource unit is a resource unit that the mobile communication terminal transmits a detection signal this time;

a first performing step, when the determining result indicates that there is a resource unit set whose interference degree is smaller than the interference parameter of the first resource unit, selecting a second resource unit from the resource unit set as a next transmission detection The resource unit of the signal.

2. The method according to claim 1, wherein the interference parameter is power on the resource unit, and the higher the power on the resource unit, the larger the interference parameter on the resource unit.

3. The method according to claim 2, wherein the signal comprises all probe signals occupying the resource unit; the power comprises power of all the sounding signals occupying the resource unit.

4. The method of claim 3, wherein the signal further comprises an interference signal occupying the resource unit; the power further comprising power of the interference signal occupying the resource unit.

The method according to any one of claims 1 to 4, further comprising: a second performing step, wherein the determining result indicates that there is no resource having a smaller degree of interference than the interference parameter of the first resource unit When the unit is aggregated, the first resource unit is still used as the resource unit for transmitting the probe signal for the next time.

The method according to claim 1, wherein the receiving step is specifically: selecting, in a device discovery period, a device discovery subframe in each K device discovery subframe connection, as all resource units are received this time. The device on the signal finds a subframe and uses the selected device discovery subframe to receive signals on all resource units, where K is an integer greater than or equal to two.

A device discovery device for D2D communication, which is used for a mobile communication terminal, wherein the mobile communication terminal is capable of transmitting a sounding signal for device discovery using a resource unit in a candidate resource set, the device discovery device comprising:

a receiving module, in a device discovery period, selecting a device discovery subframe, and using the selected device discovery subframe to receive signals on all resource units; determining a module, determining interference parameters on each resource unit, the interference The parameter reflects the degree of interference of the signal on the corresponding resource unit to the newly added detection signal;

The determining module determines, according to the interference parameter, whether there is a resource unit set whose interference degree is smaller than the interference parameter of the first resource unit, and obtains a determination result, where the first resource unit is the mobile communication terminal transmits the current The resource unit of the sounding signal;

a first execution module, when the determination result indicates that there is a resource unit set whose interference degree is smaller than the interference parameter of the first resource unit, selecting a second resource unit from the resource unit set as a next transmission detection The resource unit of the signal.

8. The apparatus according to claim 7, wherein the interference parameter is power on the resource unit, and the higher the power on the resource unit, the larger the interference parameter on the resource unit.

The device according to claim 7 or 8, wherein the device further comprises: a second execution module, wherein the determination result indicates that there is no resource unit having a degree of interference smaller than the interference parameter of the first resource unit In the case of aggregation, the first resource unit is still used as the resource unit for transmitting the probe signal for the next time.