CN108271211B

CN108271211B - Data transmission method for D2D communication

Info

Publication number: CN108271211B
Application number: CN201611260900.5A
Authority: CN
Inventors: 王彦明; 韩东林
Original assignee: China Mobile Group Ningxia Co Ltd
Current assignee: China Mobile Group Ningxia Co Ltd
Priority date: 2016-12-30
Filing date: 2016-12-30
Publication date: 2021-07-02
Anticipated expiration: 2036-12-30
Also published as: CN108271211A

Abstract

The invention provides a data transmission method for D2D communication, and relates to the technical field of communication. The method comprises the following steps: when a terminal initiates data transmission based on D2D communication, a data transmission request is sent to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data transmission request; measuring the channel quality of cells corresponding to at least one unlicensed frequency band respectively, and reporting the measurement result to a base station, so that the base station configures the cells as secondary serving cells of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cells for the terminal; when data exists in the cache of the terminal, reporting a cache state report to a base station so that the base station allocates physical resources for transmitting data and control signaling in a secondary serving cell for the terminal according to the cache state report and parameters; and sending data and control signaling in the secondary service cell according to the physical resources, thereby realizing the transmission of the data. The invention reduces unnecessary power loss of the terminal.

Description

Data transmission method for D2D communication

Technical Field

The invention relates to the technical field of communication, in particular to a data transmission method for D2D communication.

Background

In order to improve the competitiveness of the LTE (Long Term Evolution) system and meet the service requirements proposed by the operator, 3GPP (the 3rd Generation Partnership Project) started to research a new communication mode of D2D (Device to Device) discovery/communication under a cellular network from 2012. D2D is a mechanism that has emerged to address new traffic needs. It relates to the research field of all 3GPP from the business requirement to the core network architecture to the wireless access mode. 3GPP various working groups completed the first stage of research in 2014 12, and designed an inter-device communication mechanism based on D2D mode applied to the public safety field and an inter-device discovery mechanism applied to the business field; new challenges arising from the emergence of new business requirements, such as further functional enhancements to wearable devices, are subsequently considered further.

The basic process of the resource allocation mode based on base station scheduling in D2D communication is as follows:

step 1, the base station configures the resource allocation mode of D2D used by the terminal to be the resource allocation mode based on the base station scheduling. The terminal is also allocated a pool of resources for transmitting control signaling used on the D2D link.

Step 2, when the terminal has D2D data to send, a buffer status report is triggered first. And further triggering the scheduling request under the condition that the terminal has no uplink resource. The terminal sends the scheduling request to the base station.

And 3, the base station allocates an uplink resource to the terminal after receiving the scheduling request.

And step 4, the terminal sends the buffer status report aiming at the D2D data to the base station in the uplink resource.

And step 5, the base station allocates resources for data transmission on the D2D link to the terminal through the physical downlink control channel according to the buffer status report of the terminal.

And step 6, the terminal performs D2D data transmission on the resources allocated by the base station.

For D2D communication, a basic design method of a physical layer includes:

1) two types of resource pools are defined. Namely a signaling resource pool and a data resource pool. Wherein, the signaling resource pool is used for transmitting control signaling required by the D2D link for receiving decoded data, and the data resource pool is used for transmitting data on the D2D link.

2) For the resource allocation mode of base station scheduling, the base station allocates only one signaling resource pool to the terminal, that is, the signaling resource pool is allocated in the step 1. The resource pool includes: a length in a time domain, a subframe available for transmitting signaling, and a frequency domain resource available on the subframe available for transmitting signaling.

3) According to the physical resources allocated by the base station, the terminal transmits a control signaling first and then sends data; HARQ (Hybrid Automatic Repeat Request) feedback is not supported in D2D communication. To ensure the reliability of transmission, the same control signaling needs to be transmitted twice, and the same data block needs to be transmitted four times.

4) In step 5, the specific design of the physical resource allocated by the base station to the terminal for data transmission on the D2D link is as follows: and indicating the subframe used by the terminal for transmitting the control signaling twice and the frequency domain resource position on each subframe, and indicating the subframe used by transmitting the data block four times and the time domain resource position on each subframe.

Fig. 1 is a diagram illustrating a result of allocating physical resources in a resource pool period by a terminal in the prior art. As shown in fig. 1, the italic block represents a control signaling, the grid block represents a data block, the same control signaling is transmitted twice, the same control signaling is used for indicating a time domain resource location and a frequency domain resource location of a following data transmission, and the same data block is transmitted four times.

In order to face the challenges presented by increasingly strained spectrum resources, 3GPP initiated a study on how to use unlicensed frequency bands in LTE systems in 2014. Finally, the 3GPP decides to use the unlicensed Assisted Access (LAA) for data communication only by considering the LTE Licensed Assisted mode at the current stage, as shown in fig. 2. The carrier wave on the authorized frequency band is configured to the terminal as a main carrier wave, and the carrier wave on the unauthorized frequency band can only be configured to the terminal as a secondary carrier wave. On the sub-carrier of the unlicensed frequency band, the terminal can work in a downlink-only mode or in a downlink and uplink mode.

In order to ensure fairness among systems when an unlicensed frequency band is used, any device needs to first monitor whether a current channel is idle before data transmission is performed on the unlicensed frequency band. After the channel is idle for a period of time, the device can occupy the channel for data transmission. If the channel is busy as a result of the listening, the device needs to back off randomly for a period of time before it can transmit. This mechanism is called LBT (listen before talk) mechanism. In LAA, whether the terminal or the base station, when it needs to transmit data on the channel of the unlicensed band, it also needs to follow the LBT mechanism.

When the terminal needs to perform D2D communication on an unlicensed carrier configured as a secondary serving cell, it also needs to follow the LBT mechanism, involving two communication mechanisms altogether. This may be problematic for the basic procedure of resource allocation based on base station scheduling in D2D communication described above. Fig. 3 is a diagram illustrating a terminal communicating D2D on an unlicensed carrier in the prior art. As shown in fig. 3, it is assumed that the terminal triggers a Buffer State Report (BSR) for D2D communication at time T1. The base station allocates physical resources on the D2D link for resource pool period 2 to the terminal at time T2. After receiving the allocated physical resource, the terminal finds that the physical resource can accommodate all data in the current buffer. The terminal then cancels the buffer status report of the D2D communication that has been triggered. The terminal executes an LBT mechanism before each data sending subframe in the resource pool period 2 according to the physical resources allocated by the base station, and finds that the channel is busy every time. Finally, after the resource pool period 2 is over, the terminal is not able to send out the data.

For the sending end, because the data in the buffer is not sent out, the terminal cannot trigger a new buffer status report after new data arrives. This results in the terminal having D2D data to send, but never reporting a BSR to request physical resources. And the base station does not know that the terminal has not successfully transmitted the data after allocating the physical resource to the terminal at time T2. And under the condition that the terminal does not receive the buffer status report of the terminal, the terminal is not actively allocated with new physical resources. Eventually the terminal will have no physical resources to send D2D data.

For the receiving end, it may successfully receive the control signaling, and thus receive the data based on the resource location of the next data indicated in the control signaling. But the result is that the D2D link is always being listened to without receiving any data. When a plurality of terminals receive control signaling sent by the terminal and do not receive data all the time, the terminal receiving the data consumes unnecessary power.

Disclosure of Invention

The invention aims to provide a data transmission method for D2D communication. The technical problem to be solved by the method is as follows: how to enable the transmitting end to fully utilize the transmission opportunity after preempting the channel of the unauthorized frequency band and reduce the occurrence of the situation that the receiving end monitors the data but cannot receive the data all the time after monitoring the control signaling sent by the transmitting end.

In order to achieve the above object, the present invention provides a data transmission method for D2D communication. The method comprises the following steps:

when a terminal initiates data transmission based on the D2D communication, the terminal transmits a data transmission request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data transmission request;

the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission;

when data exists in the cache of the terminal, the terminal reports a cache state report to the base station so that the base station allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the cache state report and the parameters;

and the terminal sends data and control signaling in the secondary service cell according to the physical resources, thereby realizing the transmission of the data.

Optionally, before the terminal sends data and control signaling in the secondary serving cell according to the physical resource, the method further includes:

the terminal monitors whether a channel corresponding to the physical resource is idle or not;

if so, the terminal judges whether the continuous idle time length of the channel is greater than a preset time length;

and if so, the terminal sends data and control signaling in the secondary serving cell according to the physical resources.

Optionally, the parameters include:

a resource pool period for the D2D communication, a number of transmissions per control signaling, a number of transmissions per data block, and an allocation pattern of the physical resources.

Optionally, the method further comprises:

before the resource pool period or under the condition that a buffer status report is triggered in the resource pool period, the terminal evaluates whether physical resources allocated by the base station accommodate all current data in the buffer;

if so, the terminal deactivates the cache status report;

the terminal judges whether the data is successfully transmitted in the resource pool period;

if not, the terminal reactivates the buffer status report after the resource pool period is finished, and reports the buffer status report to the base station, so that the base station allocates physical resources.

Optionally, the method further comprises:

before the resource pool period or under the condition that no buffer status report is triggered in the resource pool period, the terminal judges whether the data is successfully sent in the resource pool period;

if not, the terminal triggers a new buffer status report after the resource pool period is finished, and reports the new buffer status report to the base station, so that the base station allocates physical resources.

Correspondingly, the invention also provides a data transmission method for D2D communication. The method comprises the following steps:

when a terminal initiates data transmission based on the D2D communication, a base station receives a data transmission request transmitted by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data transmission request, so that the terminal measures the channel quality of a cell corresponding to each unauthorized frequency band, and reports a measurement result;

the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for transmitting the data;

when data exists in the buffer memory of the terminal, the base station receives the buffer state report reported by the terminal, and allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the buffer state report and the parameters, so that the terminal sends the data and the control signaling in the secondary serving cell according to the physical resources, and data transmission is realized.

Optionally, the allocating, according to the buffer status report and the parameter, physical resources for sending data and control signaling in the secondary serving cell to the terminal includes:

the base station sends the parameters of the assigned physical resources to the terminal through a downlink control signaling according to the data amount in the cache of the terminal and the parameters,

the parameters of the assigned physical resources include a time domain resource position and a frequency domain resource position for sending the same control signaling each time and a time domain resource position and a frequency domain resource position for sending the same data block each time.

Optionally, the method further comprises:

and the base station indicates the time domain resource position for sending the same control signaling each time and the time domain resource position for sending the same data block each time in a bitmap mode.

when a terminal initiates data reception based on the D2D communication, the terminal sends a data reception request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data reception request;

the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission;

the terminal monitors the control instruction according to the parameters;

and when the terminal receives the control instruction, the terminal receives data according to the control instruction, so that the data transmission is realized.

when a terminal initiates data receiving based on the D2D communication, a base station receives a data receiving request sent by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data receiving request, so that the terminal measures channel quality of cells respectively corresponding to the at least one unauthorized frequency band, and reports a measuring result;

the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, so that the terminal monitors the control instruction according to the parameters and receives data according to the control instruction when receiving the control signaling, thereby realizing data transmission,

the control signaling is used for indicating a time domain resource position and a frequency domain resource position of data transmission.

According to the technical scheme, when the terminal initiates data transmission based on D2D communication, the terminal sends a data transmission request to the base station, and the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data transmission request; the terminal measures the channel quality of a cell corresponding to at least one unlicensed frequency band respectively, reports the measurement result to the base station, and the base station configures the cell as a secondary serving cell of the terminal according to the measurement result and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal; when data exists in the cache of the terminal, the terminal reports a cache state report to the base station, and the base station distributes physical resources for sending data and control signaling in a secondary service cell to the terminal according to the cache state report and the parameters; the terminal sends data and control signaling in the secondary service cell according to the physical resources, so that data transmission is realized, the transmitting end can fully utilize transmission opportunities after occupying the channel of the unauthorized frequency band, and the occurrence of the situation that the receiving end monitors the data after monitoring the control signaling sent by the transmitting end but cannot receive the data all the time can be reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from these without inventive effort.

Fig. 1 is a diagram illustrating a result of allocating physical resources in a resource pool period by a terminal in the prior art;

fig. 2 is a diagram of licensed-assisted access of an unlicensed carrier in the prior art;

fig. 3 is a diagram illustrating a terminal communicating D2D on an unlicensed carrier in the prior art;

fig. 4 is a flowchart of a data transmission method of D2D communication according to an embodiment of the present invention;

fig. 5 is a flowchart of a data transmission method for D2D communication according to another embodiment of the present invention;

fig. 6 is a flowchart of interaction between a transmitting end and a base station according to an embodiment of the present invention;

fig. 7 is a schematic diagram of a time domain resource allocation when a physical resource allocation form is distributed according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a time domain resource allocation when a physical resource allocation form is a centralized type according to an embodiment of the present invention;

fig. 9 is a flowchart of a data transmission method of D2D communication according to another embodiment of the present invention;

fig. 10 is a flowchart of a data transmission method of D2D communication according to another embodiment of the present invention;

fig. 11 is a flowchart illustrating interaction between a receiving end and a base station according to an embodiment of the present invention;

fig. 12 is a flowchart of a sending end and a receiving end interaction according to an embodiment of the present invention;

fig. 13 is a schematic diagram of a possible data transmission situation at a transmitting end according to an embodiment of the present invention;

fig. 14 is a schematic diagram of monitoring control signaling by a receiving end according to an embodiment of the present invention;

fig. 15 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram of a base station according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 4 is a flowchart of a data transmission method for D2D communication according to an embodiment of the present invention. As shown in fig. 4, a data transmission method for D2D communication according to an embodiment of the present invention includes:

in step S101, when a terminal initiates data transmission based on the D2D communication, the terminal transmits a data transmission request to a base station, so that the base station configures at least one unlicensed frequency band that needs to be measured for the terminal according to the data transmission request.

Then, in step S102, the terminal measures channel qualities of cells corresponding to the at least one unlicensed frequency band, respectively, to obtain measurement results, and reports the measurement results to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement results, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal.

Wherein the parameters include: a resource pool period for the D2D communication, a number of transmissions per control signaling, a number of transmissions per data block, and an allocation pattern of the physical resources. The control signaling is used for indicating the time domain resource position and the frequency domain resource position of data transmission.

Then, in step S103, when there is data in the buffer of the terminal, the terminal reports a buffer status report to the base station, so that the base station allocates physical resources for transmitting data and control signaling in the secondary serving cell to the terminal according to the buffer status report and the parameters.

Finally, in step S104, the terminal sends data and control signaling in the secondary serving cell according to the physical resource, so as to implement data transmission.

In a specific embodiment, prior to this step, the method further comprises: the terminal monitors whether a channel corresponding to the physical resource is idle or not; if so, the terminal judges whether the continuous idle time length of the channel is greater than a preset time length; and if so, the terminal sends data and control signaling in the secondary serving cell according to the physical resources.

Fig. 5 is a flowchart of a data transmission method for D2D communication according to another embodiment of the present invention. As shown in fig. 5, a data transmission method for D2D communication according to another embodiment of the present invention includes:

in step S201, when the terminal initiates data transmission based on the D2D communication, the base station receives a data transmission request sent by the terminal, and configures at least one unlicensed frequency band for the terminal according to the data transmission request, so that the terminal measures channel qualities of cells corresponding to the at least one unlicensed frequency band, and reports a measurement result.

Next, in step S202, the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal.

Finally, in step S203, when there is data in the buffer of the terminal, the base station receives the buffer status report reported by the terminal, and allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the buffer status report and the parameters, so that the terminal sends data and control signaling in the secondary serving cell according to the physical resources, thereby implementing data transmission.

In a specific embodiment, the allocating, to the terminal according to the buffer status report and the parameter, physical resources for sending data and control signaling in the secondary serving cell includes: and the base station sends the parameters of the appointed physical resources to the terminal through a downlink control signaling according to the data volume in the buffer memory of the terminal and the parameters, wherein the parameters of the appointed physical resources comprise a time domain resource position and a frequency domain resource position for sending the same control signaling each time and a time domain resource position and a frequency domain resource position for sending the same data block each time.

In another embodiment of the present invention, the method further comprises: and the base station indicates the time domain resource position for sending the same control signaling each time and the time domain resource position for sending the same data block each time in a bitmap mode.

In this embodiment, when a terminal initiates data transmission based on D2D communication, the terminal sends a data transmission request to a base station, and the base station configures at least one unlicensed frequency band that needs to be measured for the terminal according to the data transmission request; the terminal measures the channel quality of a cell corresponding to at least one unlicensed frequency band respectively, reports the measurement result to the base station, and the base station configures the cell as a secondary serving cell of the terminal according to the measurement result and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal; when data exists in the cache of the terminal, the terminal reports a cache state report to the base station, and the base station distributes physical resources for sending data and control signaling in a secondary service cell to the terminal according to the cache state report and the parameters; the terminal sends data and control signaling in the secondary service cell according to the physical resources, so that data transmission is realized, the transmitting end can fully utilize transmission opportunities after occupying the channel of the unauthorized frequency band, and the occurrence of the situation that the receiving end monitors the data after monitoring the control signaling sent by the transmitting end but cannot receive the data all the time can be reduced.

Fig. 6 is a flowchart of interaction between a transmitting end and a base station according to an embodiment of the present invention. As shown in fig. 6, the basic processing flow of communication between the sending end and the base station includes: when a sending end needs to send service data of an application based on D2D communication, the sending end sends a signaling to a base station to request for data sending of D2D communication; the base station configures the sending end to measure on a certain unauthorized frequency band and reports the measurement result; based on the measurement result reported by the sending end, the base station configures a cell on an unlicensed frequency band for the sending end as a secondary serving cell, and is specially used for sending D2D communication, and configures parameters for controlling signaling and data sending on the secondary serving cell for the sending end. When the buffer of the sending end has data, the sending end reports the data amount in the buffer to the base station through the buffer status report; the base station allocates a signaling/data transmission pattern to the sending end according to the data amount in the sending end buffer, and sends the signaling/data transmission pattern to the sending end through a downlink control signaling, that is, allocates a physical resource for the sending end to perform D2D communication on a secondary serving cell in an unauthorized frequency band. And the sending end sends data and control signaling in the secondary service cell according to the signaling/data transmission pattern distributed by the base station. The main service cell of the sending end is a cell on a certain authorized carrier, and the signaling/data transmission pattern comprises a time domain resource position and a frequency domain resource position for sending the same control signaling each time and a time domain resource position and a frequency domain resource position for sending the same data block each time.

For example, suppose a base station deploys a spectrum with carrier frequency F1 in the licensed band and carrier frequencies F2 and F3 in the unlicensed band. Terminal equipment UE a is terminal equipment under the base station that can support D2D communication function. Its initial primary serving Cell is Cell 1 at F1. When the application of the UE a needs to initiate data transmission based on D2D communication, the application layer thereof informs its RRC (Radio Resource Control) layer of information interaction inside the device to send a request for D2D data transmission to the base station. After receiving the request of the terminal device UE a, the base station may select to allow the UE a to perform data transmission of D2D on Cell 1, or may select to allow the UE a to perform data transmission of D2D on a Cell in a certain unlicensed frequency band. If the latter is selected, the base station configures the UE A to measure the channel quality of the cells corresponding to the unlicensed frequency bands F2 and F3 on the unlicensed frequency bands F2 and F3, respectively. UE A measures on F2 and F3 and reports the measurement results of cells on F2 and F3 to the base station. After receiving the measurement result of the UE A, the base station selects a cell with good channel quality for the UE A and configures the cell as a secondary serving cell. For example, Cell 2 on F2. Meanwhile, the following parameters need to be configured for UE a:

parameter 1: resource pool periodicity for D2D communications;

parameter 2: the number of transmissions of each control signaling;

parameter 3: the number of transmissions of each data block;

parameter 4: a resource allocation pattern.

The resource allocation mode comprises distributed and centralized mode. The following illustrates the distributed and centralized meanings. Assuming that the value of the resource pool period is 30ms, the transmission times of the control signaling for each data block is 2 times, the transmission times of each data block is 4 times, and the resource allocation form is distributed. Fig. 7 shows a possible time domain resource allocation for D2D data transmission for UE a under the configuration parameters. Assuming that the value of the resource pool period is 30ms, the transmission times of the control signaling for each data block is 2 times, the transmission times of the data block is 4 times, and the resource allocation form is centralized. Then figure 8 gives a possible time domain resource allocation for D2D data transmission for UE a under this configuration parameter.

When data arrives in the buffer of the terminal equipment UE A, the terminal equipment UE A reports the data amount in the buffer to the base station through the buffer status report. The base station allocates specific physical resources for the terminal device UE a for data transmission of D2D communication according to the data amount in the buffer of the terminal device UE a, and transmits the data to the terminal device UE a through a downlink control signaling. The parameters sent by the base station to the terminal device UE a for specifying the allocated physical resources include:

parameter 1: time domain resource location.

Parameter 2: frequency domain resource location.

The base station indicates the time domain resource position in a bitmap mode. A specific method for indicating the time domain resource location is explained by way of example below.

Assuming that the value of the resource pool period is 30ms, the transmission times of the control signaling for each data block is 2 times, the transmission times of each data block is 4 times, and the resource allocation form is distributed. In this configuration, each bit in the bitmap corresponds to three consecutive subframes in the resource pool period. Therefore, for a resource pool period of 30ms, the required number of bits is 10, and 1 may indicate that corresponding three consecutive subframes are allocated to UE a. Wherein. The first subframe of the three subframes is used for transmitting control signaling. The next two subframes are used for transmitting data blocks. For example, when the value of the bitmap is 1000010000, it indicates that the physical resources allocated to UE A are subframes 1 to 3 and subframes 16 to 18 in the resource pool period. And the 1 st sub-frame and the 16 th sub-frame are used for transmitting the same control signaling, and the 2 nd and 3rd sub-frames and the 17 th and 18 th sub-frames are used for transmitting the same data block.

Assuming that the value of the resource pool period is 30ms, the transmission times of the control signaling for each data block is 2 times, the transmission times of each data block is 4 times, and the resource allocation form is centralized. In this configuration, each bit in the bitmap corresponds to 6 consecutive subframes in the resource pool period. Therefore, for a resource pool period of 30ms, the required number of bits is 5, and corresponding six consecutive subframes can be indicated by 1 and allocated to UE a. The first two subframes of the six subframes are used for transmitting control signaling, and the subsequent four subframes are used for transmitting data blocks. For example, when the value of the bitmap is 01000, it indicates that the physical resource allocated to UE A is subframes 7 to 12 in the resource pool period. And the 7 th sub-frame and the 8 th sub-frame are used for transmitting the same control signaling, and the 9 th, 10 th, 11 th and 12 th sub-frames are used for transmitting the same data block.

Preferably, the method further comprises: before the resource pool period or under the condition that a buffer status report is triggered in the resource pool period, the terminal evaluates whether physical resources allocated by the base station accommodate all current data in the buffer; if so, the terminal deactivates the cache status report; the terminal judges whether the data is successfully transmitted in the resource pool period; if not, the terminal reactivates the buffer status report after the resource pool period is finished, and reports the buffer status report to the base station, so that the base station allocates physical resources. Before the resource pool period or under the condition that no buffer status report is triggered in the resource pool period, the terminal judges whether the data is successfully sent in the resource pool period; if not, the terminal triggers a new buffer status report after the resource pool period is finished, and reports the new buffer status report to the base station, so that the base station allocates physical resources. Therefore, the condition that the sending end cannot report the buffer status report all the time when data is sent can be avoided. Furthermore, the situation that the sending end only sends the control signaling but cannot send data can be avoided, so that unnecessary transmission of the control signaling is reduced, and the sending end is helped to save power. Furthermore, the receiving end only needs to monitor the subframe corresponding to the transmission control signaling according to the configuration parameters of the physical resources, and only needs to go to the corresponding subframe to receive the data under the condition of monitoring the control signaling, and the data can be received definitely, so that the condition that the receiving end goes to the corresponding subframe to receive the data but cannot receive the data all the time after receiving the control signaling is avoided, and unnecessary power consumption of the receiving end is reduced. Furthermore, the data amount remaining in the buffer can be reported to the base station in time under the condition that the sending end cannot send data on the physical resource allocated to the sending end by the base station due to the busy channel. The situation that the base station does not schedule physical resources for the base station for a long time is avoided, so that the data transmission rate of the sending end can be improved, and particularly, the timely transmission of information is very important in the public safety field in which the D2D technology is mainly applied in the future.

In a specific embodiment, after receiving the physical resources allocated by the base station, the UE a processes a subsequent buffer status report according to a specific data transmission condition and a trigger condition of the buffer status report. The method specifically comprises the following conditions:

before or in the resource pool period for data transmission, a certain buffer status report is triggered. And if the UE A finds that the physical resource can accommodate all data in the current buffer after the physical resource allocated by the base station is evaluated, deactivating the triggered buffer status report. Deactivation means that the buffer status report is maintained, and the buffer status report is not sent even when there is uplink resource capable of accommodating the buffer status report. In the resource pool period, if the UE a can successfully send data after listening to the channel, the UE a cancels the deactivated buffer status report after the resource pool period is finished. Otherwise, after the resource pool period is over, the UE a reactivates the buffer status report. And reporting the buffer status report to the base station under the condition of obtaining new uplink resources.

No buffer status report is triggered before or during the resource pool period in which data transmission is performed. In the resource pool period, if the UE a can successfully send data after listening to the channel, the UE a does not trigger a new buffer status report after the resource pool period ends. Otherwise, after the resource pool period is over, the UE A triggers a new buffer status report. And reporting the buffer status report to the base station under the condition of obtaining new uplink resources.

Fig. 9 is a flowchart of a data transmission method for D2D communication according to another embodiment of the present invention. As shown in fig. 9, a data transmission method for D2D communication according to another embodiment of the present invention includes:

in step S301, when a terminal initiates data reception based on the D2D communication, the terminal sends a data reception request to a base station, so that the base station configures at least one unlicensed frequency band that needs to be measured for the terminal according to the data reception request.

Then, in step S302, the terminal measures channel qualities of cells corresponding to the at least one unlicensed frequency band, respectively, to obtain measurement results, and reports the measurement results to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement results, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal.

Then, in step S303, the terminal monitors the control command according to the parameter.

Finally, in step S304, when the terminal receives the control instruction, the terminal receives data according to the control instruction, thereby implementing data transmission.

Fig. 10 is a flowchart of a data transmission method for D2D communication according to another embodiment of the present invention. As shown in fig. 10, a data transmission method for D2D communication according to another embodiment of the present invention includes:

in step S401, when the terminal initiates data reception based on the D2D communication, the base station receives a data reception request sent by the terminal, and configures at least one unlicensed frequency band for the terminal according to the data reception request, so that the terminal measures channel qualities of cells corresponding to the at least one unlicensed frequency band, and reports a measurement result.

Finally, in step S402, the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, so that the terminal monitors the control command according to the parameters, and receives data according to the control command when receiving the control signaling, thereby implementing data transmission.

In this embodiment, when the terminal initiates data reception based on the D2D communication, the terminal sends a data reception request to the base station, and the base station configures at least one unlicensed frequency band that needs to be measured for the terminal according to the data reception request; the terminal measures the channel quality of the cell corresponding to the at least one unlicensed frequency band respectively, reports the measurement result to the base station, and the base station configures the cell as a secondary serving cell of the terminal according to the measurement result and configures parameters for receiving data and controlling signaling in the secondary serving cell for the terminal; the terminal monitors the control instruction according to the parameters; when the terminal receives the control instruction, the terminal receives data according to the control instruction, so that data transmission is realized, the transmitting end can fully utilize transmission opportunities after occupying an unauthorized frequency band channel, and the occurrence of the situation that the receiving end monitors data but cannot receive the data all the time after monitoring the control signaling sent by the transmitting end can be reduced.

Fig. 11 is a flowchart illustrating interaction between a receiving end and a base station according to an embodiment of the present invention. As shown in fig. 11, the basic processing flow of communication between the receiving end and the base station is as follows: when the receiving end needs to receive the service data of the application based on the D2D communication, the receiving end sends a signaling to the base station to request the data reception of the D2D communication; the base station configures the receiving end to measure on a certain unauthorized frequency band and reports the measurement result; based on the measurement result reported by the receiving end, the base station configures a cell on an unlicensed frequency band for the receiving end as a secondary serving cell, and is specially used for receiving D2D communication, and configures parameters for controlling signaling and data reception on the secondary serving cell for the receiving end. And the receiving terminal monitors the control signaling according to the parameters and receives data according to the control signaling under the condition of receiving the control signaling. Wherein, the main service cell of the receiving end is a cell on a certain authorized carrier.

For example, suppose a base station deploys a spectrum with carrier frequency F1 in the licensed band and carrier frequencies F2 and F3 in the unlicensed band. Terminal equipment UE B is a terminal equipment under the base station that can support D2D communication function. Its initial primary serving Cell is Cell 1 at F1. When the application of the terminal device UE B needs to initiate data reception based on D2D communication, the application layer informs the RRC layer thereof through information interaction inside the device to send a request for D2D data reception to the base station. After receiving the request of the terminal device UE B, the base station may select to allow the UE B to perform data reception of D2D on Cell 1, or may select to allow the UE B to perform data reception of D2D on a Cell in a certain unlicensed frequency band. If the latter is selected, the base station configures the UE B to measure the channel quality of the cells corresponding to the unlicensed frequency bands F2 and F3 on the unlicensed frequency bands F2 and F3, respectively. And the UE B performs measurement on F2 and F3 and reports the measurement results of the cells on F2 and F3 to the base station. After receiving the measurement result of the UE B, the base station selects a cell with good channel quality for the UE B and configures the cell as a secondary serving cell. For example, Cell 2 on F2. Meanwhile, the following parameters need to be configured for UE B:

parameter 1: resource pool periodicity for D2D communications;

parameter 2: the number of transmissions of each control signaling;

parameter 3: the number of transmissions of each data block;

parameter 4: a resource allocation pattern.

The resource allocation form comprises distributed and centralized. The detailed explanation is the same as the above, and is not repeated herein.

Fig. 12 is a flowchart of a sending end and a receiving end interacting according to an embodiment of the present invention. As shown in fig. 12, the basic processing flow of communication between the transmitting end and the receiving end is as follows: the sending end executes the channel monitoring process before the transmission time corresponding to the signaling/data transmission pattern distributed by the base station. And after the continuous idle length of the channel meets the predefined time length, the sending end sends the control signaling/data at the transmission moment. The receiving end monitors the control signaling in a receiving resource pool configured for the receiving end by the base station. After receiving the control signaling, the receiving end further receives data based on the resource location of the corresponding data transmission indicated in the control signaling.

In a specific embodiment, the UE a performs a channel monitoring procedure before a transmission time corresponding to a physical resource allocated by the base station. After the channel is continuously idle for a period of time satisfying the predefined period of time, UE a transmits control signaling/data at the required transmission time. Otherwise, UE a gives up the transmission opportunity. For example, when the resource pool period is 30ms and the bitmap for allocating physical resources is 1000010000, one possible data transmission scenario for UE a is shown in fig. 13. As shown in fig. 13, before the 1 st subframe, UE a listens to the channel idle, and after the channel idle time length meets the predefined time length, performs one transmission of the same control signaling, two transmissions of the same data block, and before the 16 th subframe, UE a listens to the channel busy, and UE a gives up the opportunity to transmit the same control signaling and the same data block.

In a specific embodiment, UE B listens for control signaling during a reception resource pool period configured for it by the base station. After receiving the control signaling, the terminal device further receives data based on the resource location indicated in the control signaling and corresponding to the data transmission. Since the control signaling is only sent in certain subframes of the resource pool period, UE B only needs to listen to these subframes. For example, when the resource pool period is 30ms, the number of transmission times of each control signaling is 1, the number of transmission times of each data block is 2, and the resource allocation manner is distributed, the UE B may listen to the control signaling in the manner shown in fig. 14.

For simplicity of explanation, the method embodiments are described as a series of acts or combinations, but those skilled in the art will appreciate that the embodiments are not limited by the order of acts described, as some steps may occur in other orders or concurrently with other steps in accordance with the embodiments of the invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.

Fig. 15 is a schematic structural diagram of a terminal according to an embodiment of the present invention. As shown in fig. 15, the terminal includes: a processor (processor)501, a memory (memory)502, a communication Interface (Communications Interface)503, and a communication bus 504;

the processor 501, the memory 502 and the communication interface 503 complete mutual communication through the communication bus 504;

the communication interface 503 is used for information transmission between the terminal and the base station;

the processor 501 is configured to call program instructions in the memory 502 to perform the methods provided by the above-mentioned method embodiments, for example, including: when a terminal initiates data transmission based on the D2D communication, the terminal transmits a data transmission request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data transmission request; the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission; when data exists in the cache of the terminal, the terminal reports a cache state report to the base station so that the base station allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the cache state report and the parameters; and the terminal sends data and control signaling in the secondary service cell according to the physical resources, thereby realizing the transmission of the data. Examples further include: when a terminal initiates data reception based on the D2D communication, the terminal sends a data reception request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data reception request; the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission; the terminal monitors the control instruction according to the parameters; and when the terminal receives the control instruction, the terminal receives data according to the control instruction, so that the data transmission is realized.

The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising: when a terminal initiates data transmission based on the D2D communication, the terminal transmits a data transmission request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data transmission request; the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission; when data exists in the cache of the terminal, the terminal reports a cache state report to the base station so that the base station allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the cache state report and the parameters; and the terminal sends data and control signaling in the secondary service cell according to the physical resources, thereby realizing the transmission of the data. Examples further include: when a terminal initiates data reception based on the D2D communication, the terminal sends a data reception request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data reception request; the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission; the terminal monitors the control instruction according to the parameters; and when the terminal receives the control instruction, the terminal receives data according to the control instruction, so that the data transmission is realized.

The present embodiments provide a non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the methods provided by the above method embodiments, for example, including: when a terminal initiates data transmission based on the D2D communication, the terminal transmits a data transmission request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data transmission request; the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission; when data exists in the cache of the terminal, the terminal reports a cache state report to the base station so that the base station allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the cache state report and the parameters; and the terminal sends data and control signaling in the secondary service cell according to the physical resources, thereby realizing the transmission of the data. Examples further include: when a terminal initiates data reception based on the D2D communication, the terminal sends a data reception request to a base station, so that the base station configures at least one unlicensed frequency band which needs to be measured for the terminal according to the data reception request; the terminal measures the channel quality of the cell corresponding to each of the at least one unlicensed frequency band to obtain a measurement result, and reports the measurement result to the base station, so that the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission; the terminal monitors the control instruction according to the parameters; and when the terminal receives the control instruction, the terminal receives data according to the control instruction, so that the data transmission is realized.

Fig. 16 is a schematic structural diagram of a base station according to an embodiment of the present invention. As shown in fig. 16, the base station includes: a processor (processor)601, a memory (memory)602, a communication Interface (Communications Interface)603, and a communication bus 604;

the processor 601, the memory 602 and the communication interface 603 complete mutual communication through the communication bus 604;

the communication interface 603 is used for information transmission between the base station and the terminal;

the processor 601 is configured to call program instructions in the memory 602 to perform the methods provided by the above-mentioned method embodiments, for example, including: when a terminal initiates data transmission based on the D2D communication, a base station receives a data transmission request transmitted by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data transmission request, so that the terminal measures the channel quality of a cell corresponding to each unauthorized frequency band, and reports a measurement result; the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for transmitting the data; when data exists in the buffer memory of the terminal, the base station receives the buffer state report reported by the terminal, and allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the buffer state report and the parameters, so that the terminal sends the data and the control signaling in the secondary serving cell according to the physical resources, and data transmission is realized. Examples further include: when a terminal initiates data receiving based on the D2D communication, a base station receives a data receiving request sent by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data receiving request, so that the terminal measures channel quality of cells respectively corresponding to the at least one unauthorized frequency band, and reports a measuring result; and the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, so that the terminal monitors the control command according to the parameters, and receives the data according to the control command when receiving the control signaling, thereby realizing data transmission, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission.

The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising: when a terminal initiates data transmission based on the D2D communication, a base station receives a data transmission request transmitted by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data transmission request, so that the terminal measures the channel quality of a cell corresponding to each unauthorized frequency band, and reports a measurement result; the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for transmitting the data; when data exists in the buffer memory of the terminal, the base station receives the buffer state report reported by the terminal, and allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the buffer state report and the parameters, so that the terminal sends the data and the control signaling in the secondary serving cell according to the physical resources, and data transmission is realized. Examples further include: when a terminal initiates data receiving based on the D2D communication, a base station receives a data receiving request sent by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data receiving request, so that the terminal measures channel quality of cells respectively corresponding to the at least one unauthorized frequency band, and reports a measuring result; and the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, so that the terminal monitors the control command according to the parameters, and receives the data according to the control command when receiving the control signaling, thereby realizing data transmission, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission.

The present embodiments provide a non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the methods provided by the above method embodiments, for example, including: when a terminal initiates data transmission based on the D2D communication, a base station receives a data transmission request transmitted by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data transmission request, so that the terminal measures the channel quality of a cell corresponding to each unauthorized frequency band, and reports a measurement result; the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for transmitting data and control signaling in the secondary serving cell for the terminal, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for transmitting the data; when data exists in the buffer memory of the terminal, the base station receives the buffer state report reported by the terminal, and allocates physical resources for sending data and control signaling in the secondary serving cell to the terminal according to the buffer state report and the parameters, so that the terminal sends the data and the control signaling in the secondary serving cell according to the physical resources, and data transmission is realized. Examples further include: when a terminal initiates data receiving based on the D2D communication, a base station receives a data receiving request sent by the terminal, and configures at least one unauthorized frequency band for the terminal according to the data receiving request, so that the terminal measures channel quality of cells respectively corresponding to the at least one unauthorized frequency band, and reports a measuring result; and the base station configures the cell as a secondary serving cell of the terminal according to the measurement result, and configures parameters for receiving data and control signaling in the secondary serving cell for the terminal, so that the terminal monitors the control command according to the parameters, and receives the data according to the control command when receiving the control signaling, thereby realizing data transmission, wherein the control signaling is used for indicating a time domain resource position and a frequency domain resource position for data transmission.

Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

The above-described embodiments of the terminal or the base station are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present invention, and are not limited thereto; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A data transmission method for D2D communication, the method comprising:

2. The data transmission method of D2D communication according to claim 1, wherein before the terminal sends data and control signaling in the secondary serving cell according to the physical resource, the method further comprises:

3. The data transmission method of the D2D communication according to claim 1, wherein the parameters include:

4. The data transmission method of the D2D communication according to claim 3, wherein the method further comprises:

if so, the terminal deactivates the cache status report;

5. The data transmission method of the D2D communication according to claim 3, wherein the method further comprises:

6. A data transmission method for D2D communication, the method comprising:

7. The data transmission method of the D2D communication of claim 6, wherein the allocating physical resources for the terminal to send data and control signaling in the secondary serving cell according to the buffer status report and the parameters comprises:

8. The data transmission method of the D2D communication according to claim 7, wherein the method further comprises:

9. A data transmission method for D2D communication, the method comprising:

the terminal monitors the control instruction according to the parameters;

10. A data transmission method for D2D communication, the method comprising: