WO2015113326A1

WO2015113326A1 - Method and apparatus for selecting communication mode and terminal

Info

Publication number: WO2015113326A1
Application number: PCT/CN2014/075619
Authority: WO
Inventors: 张晨璐; 张云飞; 曹一卿; 王晓勇; 董贤东
Original assignee: 宇龙计算机通信科技(深圳)有限公司
Priority date: 2014-01-28
Filing date: 2014-04-17
Publication date: 2015-08-06
Also published as: CN103781016A

Abstract

The present invention provides a method for selecting a communication mode. The method comprises the following steps: receiving a detection signal from a target communication device and obtaining a reception condition parameter of the detection signal (102); and selecting a communication mode with respect to the target communication device according to a numerical relationship between the value of the reception condition parameter and a preset threshold value (104). The present invention also provides an apparatus for selecting a communication mode and a terminal. By means of the technical solution of the present invention, the most suitable communication mode can be selected under different channel conditions, and the frequency utilization can be improved while the communication quality is guaranteed.

Description

Communication mode selection method and selection device, terminal

Technical field

The present invention relates to the field of wireless communication technologies, and in particular, to a method for selecting a communication mode, a device for selecting a communication mode, and a terminal. Background technique

In the related art, a communication mode is proposed, that is, direct communication between a terminal and a terminal

(Device to Device, D2D communication), so that data packets can be transmitted directly between terminals without any intermediate infrastructure (such as base stations, core networks, etc.), or only through relays such as base stations or other terminals. To achieve a longer transmission distance.

However, for various application scenarios, how to determine whether the terminal should use the D2D mode for communication or to communicate in the traditional non-D2D mode has become a technical problem to be solved. Summary of the invention

The present invention is based on the above problems, and proposes a new technical solution, which can select the most suitable communication mode under different channel conditions, and helps to improve the frequency utilization while ensuring the communication quality.

In view of this, the present invention provides a method for selecting a communication mode, including: receiving a sounding signal from a target communication device, and acquiring a receiving condition parameter of the sounding signal; and determining a value according to the receiving condition parameter and a preset The numerical relationship between the threshold values selects the communication mode with the target communication device.

In the technical solution, by acquiring the reception status parameter of the detection signal from the target communication device, the real-time channel status with the target communication device can be determined according to the value of the reception status parameter, and the most suitable communication mode can be selected accordingly. . For example, when the real-time channel condition is poor, the relay D2D communication mode or the traditional communication mode can be selected, when the real-time channel condition is poor. When using the direct D2D communication mode.

Among them, the preset threshold value may be one or more, and the combination of multiple thresholds helps to implement more optional communication modes.

In the above technical solution, preferably, the receiving condition parameter comprises: a signal receiving power and/or a signal receiving quality. It should be understood by those skilled in the art that the receiving condition parameters are not limited herein, and it is obvious that the measurement of the real-time channel condition can be realized by other more types of parameters.

In the above technical solution, preferably, the method further includes: when the value of the receiving condition parameter is greater than or equal to a preset first threshold, selecting a direct D2D mode as a communication mode with the target communication device.

In the technical solution, when the value of the receiving condition parameter is greater than or equal to the first threshold, it indicates that the current real-time channel condition is good, and thus the communication through the direct D2D mode helps to improve the frequency utilization.

In the above technical solution, preferably, the method further includes: when the value of the receiving condition parameter is greater than a preset second threshold value and less than a preset first threshold value, selecting a D2D communication manner based on a communication enhancement mechanism As a communication mode with the target communication device, or after temporarily selecting a direct D2D mode as a communication mode with the target communication device, the D2D communication mode based on the communication enhancement mechanism is adjusted.

In the technical solution, when the value of the receiving condition parameter is between the first threshold and the second threshold, it indicates that the current real-time channel condition is good, but may affect the communication quality in the direct D2D mode. Therefore, the D2D communication method using the communication enhancement mechanism helps to improve the communication quality, thereby improving the frequency utilization and ensuring sufficient communication quality through the D2D method.

In the foregoing technical solution, the D2D communication mode based on the communication enhancement mechanism includes: a direct D2D mode based on a first power emission level; wherein, the first power emission level is greater than a current second power Launch level.

In this technical solution, by improving the power transmission level, when the real-time channel condition is not ideal, the direct communication mode can still be communicated with the target communication device, and high communication quality can be ensured, especially in the communication parties. When they are not within the coverage of the base station, It helps to ensure the reliability of communication establishment.

In addition, if the communication quality still fails to reach the preset standard after adjusting to the first power transmission level, the original second power emission level can be recalled to avoid excessive power consumption; at the same time, it can be switched to other communication. Modes, such as relayed D2D communication mode or traditional communication mode, in order to obtain better communication quality.

In the above technical solution, preferably, determining a value of the first power transmission level according to a preset power control parameter; and/or before communicating by using the direct D2D mode based on the first power emission level The method further includes: negotiating with the target communication device to determine a value of the first power transmission level.

In this technical solution, as a more preferred embodiment, the power emission level can be adjusted based on power control parameters preset by itself or the network side, thereby facilitating rapid power emission level adjustment.

As another preferred embodiment, the value of the first power transmission level may be jointly determined by the negotiation of the communication device, and the preset value is too low to cause poor communication quality, or the preset value is too high. Large power consumption.

In the foregoing technical solution, preferably, if the negotiation is performed with the target communication device, the method for selecting the communication mode further includes: when both parties are in the wireless network coverage area, the base station and the negotiation party Separately establishing a signaling connection to implement the negotiation process; or implementing the negotiation process by using the detection signal; or starting an upper layer application to implement the negotiation process through a core network; or when a direct D2D mode has been temporarily selected , interacting through this direct D2D approach.

In the above technical solution, preferably, the D2D communication method based on the communication enhancement mechanism comprises: a relay-based D2D mode.

In this technical solution, the relay may be a base station, a mobile base station or other terminal equipment, and may perform data and/or signaling forwarding on both sides of the relay-based D2D communication. Due to the presence of relays, farther and more stable D2D communication can be achieved by relaying when the distance between the two devices is far and/or the communication quality is not good enough.

In the above technical solution, preferably, the method further includes: negotiating with the target communication device to determine a communication device as a relay. In this technical solution, there may be different devices around the communication parties, and the most suitable communication device can be selected as a relay through negotiation. For example, when the distance between the two communication parties is relatively close, the other device can pass other The terminal device acts as a relay; when the distance between the two communication parties is far and is in the same cell, the base station that establishes connection between the two devices can be used as a relay; when the distance between the two communication parties is far and is in different cells, two devices can pass The base stations each of which establishes a connection are used as relays, and the two base stations can interact with each other through, for example, an X2 interface.

In any of the above technical solutions, preferably, the method further includes: monitoring a communication status with the target communication device; and adjusting a communication mode with the target communication device according to the change of the communication status.

In this technical solution, after selecting any communication mode, it is still necessary to monitor the communication status between the current communication device and the target communication device: if the communication condition is good, no change is needed; if the communication condition is deteriorated or exists The trend of deterioration can adjust the communication mode in time, such as switching from direct D2D mode to relay-based D2D mode, or switching from relay-based D2D mode to traditional communication mode, such as 2G, 3G, 4G and other mobile communication. Ways to ensure better communication quality as much as possible.

The present invention also provides a communication mode selection apparatus, including: a parameter acquisition unit, configured to receive a detection signal from a target communication device, and acquire a reception status parameter of the detection signal; and a mode selection unit, configured to A numerical relationship between the value of the reception status parameter and a preset threshold value is selected, and a communication mode with the target communication device is selected.

In the technical solution, by acquiring the reception status parameter of the detection signal from the target communication device, the real-time channel status with the target communication device can be determined according to the value of the reception status parameter, and the most suitable communication mode can be selected accordingly. . For example, when the real-time channel condition is poor, the relay D2D communication mode or the traditional communication mode can be selected. When the real-time channel condition is poor, the direct D2D communication mode can be selected. Among them, the preset threshold value can be one or more, and the combination of multiple thresholds can help achieve more optional communication modes.

In the above technical solution, preferably, the receiving condition parameter includes: a signal receiving power and/or a signal receiving quality. It should be understood by those skilled in the art that the reception status parameter is not limited herein, and it is obvious that the measurement of the real-time channel condition can be realized by other more types of parameters. In the above technical solution, preferably, the mode selecting unit is configured to: when the value of the receiving condition parameter is greater than or equal to a preset first threshold, select a direct D2D mode as the target communication device Communication mode.

In the above technical solution, preferably, the mode selecting unit is configured to: when the value of the receiving condition parameter is greater than a preset second threshold value and less than a preset first threshold value, selecting to enhance based on communication The D2D communication mode of the mechanism is adjusted to the communication enhancement mechanism-based D2D communication mode after the communication mode with the target communication device or after temporarily selecting the direct D2D mode as the communication mode with the target communication device.

In this technical solution, by improving the power transmission level, when the real-time channel condition is not ideal, the direct communication mode can still be communicated with the target communication device, and high communication quality can be ensured, especially in the communication parties. When they are not within the coverage of the base station, it obviously helps to ensure the reliability of communication establishment.

In the above technical solution, preferably, the method further includes a value determining unit, and the value determining unit further includes: an obtaining subunit, configured to acquire a preset power control parameter, to determine Deriving a value of a first power transmission level; and/or a negotiating subunit for negotiating with the target communication device to communicate with the direct D2D mode based on the first power transmission level to determine The value of the first power emission level is described.

In the above technical solution, preferably, the negotiating subunit is configured to: when the two parties are in the wireless network coverage area, implement the negotiation process by using a signaling connection established between the base station and the negotiating party respectively; or The detecting signal implements the negotiation process; or the upper layer application is started to implement the negotiation process through the core network; or when the direct D2D mode has been temporarily selected, the direct D2D mode is used for interaction.

In the above technical solution, preferably, the method further includes: a relay determining unit, configured to negotiate with the target communication device to determine a communication device as a relay.

In this technical solution, there may be different devices around the communication parties, and the most suitable communication device can be selected as a relay through negotiation. For example, when the distance between the two communication parties is relatively close, the other device can pass other The terminal device acts as a relay; when the distance between the two communication parties is far and is in the same cell, the base station that establishes connection between the two devices can be used as a relay; when the distance between the two communication parties is far and is in different cells, two The base stations each of which establishes a connection are used as relays, and the two base stations can interact with each other through, for example, an X2 interface. In any one of the foregoing technical solutions, the method further includes: a communication status monitoring unit, configured to monitor a communication status with the target communication device; and a mode adjustment unit, configured to adjust according to the change of the communication status A mode of communication with the target communication device.

The present invention also provides a terminal, comprising: the selection device of the communication mode according to any one of the above technical solutions.

Through the above technical solutions, the most suitable communication mode can be selected under different channel conditions, which helps to improve the frequency utilization while ensuring the communication quality. DRAWINGS

1 is a schematic flow chart showing a method of selecting a communication mode according to an embodiment of the present invention;

2 is a schematic flow chart showing a selection communication mode according to an embodiment of the present invention; FIG. 3 is a schematic flow chart showing a selection communication mode according to another embodiment of the present invention;

Figure 4 is a schematic block diagram showing a selection mode of a communication mode according to an embodiment of the present invention;

Figure 5 shows a schematic block diagram of a terminal in accordance with one embodiment of the present invention. detailed description

The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be combined with each other. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention, but the invention may be practiced in other embodiments other than those described herein. Limitations of specific embodiments.

Fig. 1 shows a schematic flow chart of a method of selecting a communication mode in accordance with one embodiment of the present invention.

As shown in FIG. 1, a method for selecting a communication mode according to an embodiment of the present invention includes:

Step 102: Receive a sounding signal from a target communication device, and acquire a receiving condition parameter of the sounding signal.

Step 104: Select a communication mode with the target communication device according to a numerical relationship between the value of the receiving condition parameter and a preset threshold.

In the technical solution, by acquiring the reception status parameter of the detection signal from the target communication device, the real-time channel status with the target communication device can be determined according to the value of the reception status parameter, and the most suitable communication mode can be selected accordingly. . For example, when the real-time channel condition is poor, the relay D2D communication mode or the traditional communication mode can be selected. When the real-time channel condition is poor, the direct D2D communication mode can be selected.

First, the detection signal

A sequence of known characteristics is transmitted by the target communication device for use in the channel sounding process. Specifically, the foregoing sequence may be an uplink SRS pilot signal sent by the target communication device, or may be a newly defined D2D pilot sequence, or may be a synchronization signal sent by the target communication device (when the target communication device is simultaneously a synchronization source) ).

Second, the receiving status parameters

Preferably, the receiving condition parameter comprises: signal receiving power and/or signal receiving quality. It should be understood by those skilled in the art that the reception status parameter is not limited herein, and it is obvious that the measurement of the real-time channel condition can be realized by other more types of parameters.

Third, mode selection 2 shows a schematic flow chart of selecting a communication mode in accordance with one embodiment of the present invention. As shown in FIG. 2, the process of selecting a communication mode according to an embodiment of the present invention includes: Step 202: Receive a sounding signal from a target communication device to obtain a value of a corresponding receiving condition parameter, assuming that the value is T.

Step 204: When the value of the receiving status parameter is greater than or equal to a preset first threshold, selecting a direct D2D mode as the communication mode with the target communication device.

Specifically, for example, if the first threshold value is T1, then Τ > Τ1, proceed to step 208 to communicate using the direct D2D mode, otherwise proceed to step 206.

Step 206: When the value of the receiving condition parameter is greater than a preset second threshold value and less than a preset first threshold value, selecting a D2D communication mode based on a communication enhancement mechanism as the communication with the target communication device The mode, or after temporarily selecting the direct D2D mode as the communication mode with the target communication device, adjusts to the communication enhancement mechanism based D2D communication mode.

Specifically, for example, if the second threshold value may be Τ2, then when Τ2 Τ Τ1, you may directly proceed to step 210 to communicate using the enhanced D2D mode; or temporarily enter step 208 to communicate using the direct D2D mode, and then Proceeding to step 210, the terminal finally switches to the enhanced D2D mode for communication, otherwise proceeds to step 212, that is, the communication is performed by the conventional communication mode other than the D2D mode.

Fourth, the enhancement mechanism

Embodiment 1: Improving the power emission level In the foregoing technical solution, the D2D communication mode based on the communication enhancement mechanism includes: a direct D2D mode based on a first power emission level; wherein, the first power emission level is greater than a current second power Launch level.

Embodiment 2: Relay D2D communication In the above technical solution, preferably, the D2D communication method based on the communication enhancement mechanism includes: a relay-based D2D mode.

In the above technical solution, preferably, the method further includes: negotiating with the target communication device to determine a communication device as a relay.

In this technical solution, there may be different devices around the communication parties, and the most suitable communication device can be selected as a relay through negotiation. For example, when the distance between the two communication parties is relatively close, the other device can pass other The terminal device acts as a relay; when the distance between the two communication parties is far and is in the same cell, the base station that establishes connection between the two devices can be used as a relay; when the distance between the two communication parties is far and is in different cells, two The base stations each of which establishes a connection are used as relays, and the two base stations can interact with each other through, for example, an X2 interface.

V. Continuous monitoring

Fig. 3 shows a schematic flow chart of selecting a communication mode in accordance with another embodiment of the present invention.

As shown in FIG. 3, the process of selecting a communication mode according to another embodiment of the present invention includes:

Step 302, parameter setting. 1, the threshold

Specifically, the threshold value is used in step 308 for the selection of a particular communication mode. The threshold can be a value; or, the threshold can be multiple values, so that more thresholds can be combined to achieve more choices.

1) Threshold type

When receiving the sounding signal from the target communication device, it should be specifically defined: whether the received power of the sounding signal is analyzed, or whether the receiving quality of the signal is analyzed.

2) Threshold combination

Specifically, for example, the following threshold values and corresponding interval combinations can be set:

The first threshold A, if the received power and/or the received quality of the detected signal is greater than (or not less than) A, the current channel status is good, and the direct D2D communication mode can be selected.

The second threshold B, if the received power and/or the received quality of the detected signal is less than (or not greater than) A and greater than (or not less than) B, the current channel state is better, and the enhancement may be selected. D2D communication mode.

At the same time, if the received power and/or the received quality of the detected signal is less than (or not greater than) B, the current channel state is poor, and it is not applicable to the D2D communication mode. The traditional communication mode, such as 2G, 3G, should be selected. Or mobile communication mode such as 4G.

2, power adjustment parameters

The power adjustment parameter is used to enhance the reliability of the D2D communication mode and improve the communication quality by adjusting the transmission power level. Specifically, the power adjustment parameters may include:

Power adjustment step size δ : indicates the step size for each power adjustment;

Number of attempts Ν: indicates the maximum number of power adjustments;

Power adjustment target value Ρ: Indicates the default power value to be used at the next search;

Current power and maximum power of the UE: Indicates the power value and maximum transmit power value used by the UE for current search.

3, relay information

When a relay-based D2D communication mode is required, a specific relay device type (such as a base station, a mobile base station, other UE devices, etc.), a relay identifier ID, an authorization information, and the like are included. Each of the above parameters (or auxiliary information) can be obtained by any one of the following methods or a combination thereof:

1) Network-assisted interaction

When both communication parties are in the wireless network coverage area, the auxiliary information interaction may be performed by using a signaling connection established between the base station and the communication parties.

2) Interactive mode based on D2D channel

The above auxiliary information is carried in the Discovery message during the D2D search process for interaction. Such as two-way search signaling: Discovery request and Discovery response; or one-way Discovery message.

3) Based on the interaction of the upper application

In application-based D2D communication, the above information can be collected in the application information and interacted and negotiated through the core network in the form of IP packets.

4) Parameter preset mode

The foregoing parameters may be pre-set to the UE, for example, the parameters may be statically configured in the subscription data of the UE.

Step 304, a search operation.

Specifically, the target communication device transmits the foregoing detection signal on the preset or dynamically allocated resources, so that the current communication device measures the received detection signal, such as the received power and/or reception quality.

Step 306, channel evaluation.

Specifically, the current search result is evaluated based on the channel condition corresponding to the threshold value and the interval combination of the threshold values to determine the channel condition.

Step 308, mode selection.

Specifically, the corresponding communication mode is determined according to a specific channel condition. For example, when the channel condition is good, the direct D2D communication mode can be used; when the channel condition is good, the enhanced D2D communication mode can be used; when the channel condition is poor, the traditional communication mode other than D2D can be used.

FIG. 4 shows a schematic block of a selection mode of a communication mode according to an embodiment of the present invention. As shown in FIG. 4, the selection mode 400 of the communication mode according to an embodiment of the present invention includes: a parameter acquisition unit 402, configured to receive a detection signal from a target communication device, and acquire a reception status parameter of the detection signal; The mode selection unit 404 is configured to select a communication mode with the target communication device according to a numerical relationship between the value of the reception status parameter and a preset threshold.

In the above technical solution, preferably, the mode selecting unit 404 is configured to: when the value of the receiving condition parameter is greater than or equal to a preset first threshold, select a direct D2D mode to communicate with the target. The communication mode of the device.

In the above technical solution, preferably, the mode selecting unit 404 is configured to: when the value of the receiving condition parameter is greater than a preset second threshold value and less than a preset first threshold value, select a communication based The D2D communication mode of the enhancement mechanism is adjusted to the communication enhancement mechanism-based D2D communication mode after the communication mode with the target communication device or after temporarily selecting the direct D2D mode as the communication mode with the target communication device.

In the technical solution, when the value of the receiving condition parameter is between the first threshold and the second threshold, it indicates that the current real-time channel condition is good, but may affect the direct D2D mode. Communication quality. Therefore, the D2D communication method using the communication enhancement mechanism can improve the communication quality, thereby improving the frequency utilization rate and ensuring sufficient communication quality through the D2D method.

In the above technical solution, preferably, the value determining unit 406 is further included, and the value determining unit further includes: an obtaining subunit 4062, configured to acquire a preset power control parameter, to determine the first power emission level. a value; and/or a negotiation sub-unit 4064, configured to negotiate with the target communication device to determine the first power emission level prior to communicating with the direct D2D mode based on the first power transmission level The value.

In the foregoing technical solution, the negotiation sub-unit 4064 is configured to: when the negotiation parties are both in the wireless network coverage area, implement the negotiation process by using a signaling connection established between the base station and the negotiation two parties respectively; or Implementing the negotiation process by using the sounding signal; or starting an upper layer application to implement the negotiation process through a core network; or when the direct selection has been made directly In the D2D mode, interaction is performed by the direct D2D method.

In the above technical solution, preferably, the method further includes: a relay determining unit 408, configured to negotiate with the target communication device to determine a communication device as a relay.

In any one of the foregoing technical solutions, the method further includes: a communication status monitoring unit 410, configured to monitor a communication status with the target communication device; and a mode adjustment unit 412, configured to change according to the communication status And adjusting a communication mode with the target communication device.

Figure 5 shows a schematic block diagram of a terminal in accordance with one embodiment of the present invention.

As shown in FIG. 5, a terminal 500 according to an embodiment of the present invention includes a selection mode 400 of a communication mode as shown in FIG.

The technical solution of the present invention is described in detail above with reference to the accompanying drawings. The present invention provides a method for selecting a communication mode, a device for selecting a communication mode, and a terminal, which can be in different letters. In the case of the channel, selecting the most suitable communication mode helps to improve the frequency utilization while ensuring the communication quality.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

Claim

A method for selecting a communication mode, comprising:

Receiving a sounding signal from the target communication device, and acquiring a receiving condition parameter of the sounding signal;

And selecting a communication mode with the target communication device according to a numerical relationship between the value of the reception status parameter and a preset threshold value.

2. The method of selecting a communication mode according to claim 1, wherein the reception status parameter comprises: signal reception power and/or signal reception quality.

3. The method for selecting a communication mode according to claim 1, further comprising:

When the value of the reception status parameter is greater than or equal to the preset first threshold, the direct D2D mode is selected as the communication mode with the target communication device.

4. The method for selecting a communication mode according to claim 1, further comprising:

When the value of the receiving condition parameter is greater than a preset second threshold value and less than a preset first threshold value, selecting a D2D communication mode based on the communication enhancement mechanism as a communication mode with the target communication device, or After temporarily selecting the direct D2D mode as the communication mode with the target communication device, the D2D communication mode based on the communication enhancement mechanism is adjusted.

The method for selecting a communication mode according to claim 4, wherein the D2D communication method based on the communication enhancement mechanism comprises:

Direct D2D mode based on the first power emission level;

The first power transmission level is greater than the current second power transmission level.

The method for selecting a communication mode according to claim 5, wherein the value of the first power emission level is determined according to a preset power control parameter;

And/or prior to communicating with the direct D2D mode based on the first power transmission level, the method further comprising: negotiating with the target communication device to determine a value of the first power emission level.

The method for selecting a communication mode according to claim 6, wherein if the negotiation with the target communication device is required, the method for selecting the communication mode further includes: when both parties are in a wireless network coverage area Internally, the negotiation process is implemented by a signaling connection established between the base station and the negotiating parties respectively;

Or implementing the negotiation process by using the detection signal;

Or starting an upper layer application to implement the negotiation process through the core network;

Or when the direct D2D mode has been temporarily selected, the direct D2D mode is used for interaction.

Relay-based D2D mode.

9. The method of selecting a communication mode according to claim 8, further comprising:

Negotiating with the target communication device to determine a communication device as a relay.

The method of selecting a communication mode according to any one of claims 1 to 9, further comprising:

Monitoring a communication status with the target communication device;

A communication mode with the target communication device is adjusted in accordance with a change in the communication condition.

A device for selecting a communication mode, comprising:

a parameter obtaining unit, configured to receive a sounding signal from the target communication device, and acquire a receiving condition parameter of the probed J signal;

And a mode selection unit, configured to select a communication mode with the target communication device according to a numerical relationship between a value of the reception status parameter and a preset threshold value.

12. The communication mode selection device according to claim 11, wherein the reception status parameter comprises: signal reception power and/or signal reception quality.

13. The communication mode selection device according to claim 11, wherein the mode selection unit is configured to:

When the value of the receiving condition parameter is greater than or equal to a preset first threshold, select straight The D2D mode is connected as a communication mode with the target communication device.

14. The communication mode selection device according to claim 11, wherein the mode selection unit is configured to:

The communication mode selection device according to claim 14, wherein the D2D communication method based on the communication enhancement mechanism comprises:

Direct D2D mode based on the first power emission level;

The device for selecting a communication mode according to claim 15, further comprising a value determining unit, wherein the value determining unit further comprises:

Obtaining a subunit, configured to acquire a preset power control parameter to determine a value of the first power emission level;

And/or negotiating subunits for negotiating with the target communication device to determine a value of the first power transmission level prior to communicating with the direct D2D mode based on the first power transmission level.

17. The communication mode selection device according to claim 16, wherein the negotiation subunit is used to:

When the negotiation parties are both in the wireless network coverage area, the negotiation process is implemented by a signaling connection established between the base station and the negotiation parties respectively;

Or implementing the negotiation process by using the detection signal;

18. The communication mode selection device according to claim 14, wherein the D2D communication method based on the communication enhancement mechanism comprises:

Relay-based D2D mode.

The device for selecting a communication mode according to claim 18, further comprising:

And a relay determining unit, configured to negotiate with the target communication device to determine a communication device as a relay.

The device for selecting a communication mode according to any one of claims 11 to 19, further comprising:

a communication status monitoring unit, configured to monitor a communication status with the target communication device; and a mode adjustment unit, configured to adjust a communication mode with the target communication device according to the change of the communication status.

A terminal, comprising: the selection means of the communication mode according to any one of claims 11 to 20.