KR20130035964A - Method for device-to-device communication based on cellular telecommunication system - Google Patents

Method for device-to-device communication based on cellular telecommunication system Download PDF

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Publication number
KR20130035964A
KR20130035964A KR1020120109143A KR20120109143A KR20130035964A KR 20130035964 A KR20130035964 A KR 20130035964A KR 1020120109143 A KR1020120109143 A KR 1020120109143A KR 20120109143 A KR20120109143 A KR 20120109143A KR 20130035964 A KR20130035964 A KR 20130035964A
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South Korea
Prior art keywords
d2d communication
distributed control
terminal
method
control d2d
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KR1020120109143A
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Korean (ko)
Inventor
안재영
예충일
이경석
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한국전자통신연구원
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Priority to KR1020110100056 priority
Application filed by 한국전자통신연구원 filed Critical 한국전자통신연구원
Priority claimed from US13/630,700 external-priority patent/US8848700B2/en
Publication of KR20130035964A publication Critical patent/KR20130035964A/en

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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W56/00Synchronisation arrangements
    • H04W56/001Synchronization between nodes
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/04Wireless resource allocation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W76/00Connection management
    • H04W76/10Connection setup
    • H04W76/14Direct-mode setup
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W84/00Network topologies
    • H04W84/02Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04Large scale networks; Deep hierarchical networks
    • H04W84/042Public Land Mobile systems, e.g. cellular systems

Abstract

A cellular network based device to device communication method is disclosed. A method of operating a terminal supporting cellular network-based D2D communication includes determining, by the terminal, whether to perform central control D2D communication or distributed control D2D communication, and the terminal performs distributed control D2D communication or central control based on the determination. Requesting the base station for the setting for the D2D communication. Using the cellular network-based D2D communication method according to the present invention, it is possible to configure the cellular communication, the central control D2D and the distributed control D2D communication flexibly and selectively in the cellular network.

Description

Method for direct communication between cellular networks based on {method for device-to-device communication based on cellular telecommunication system}

The present invention relates to a direct connection communication method between terminals, and more particularly, to a method for realizing direct connection communication between terminals in a cellular network system.

Direct communication between terminals (hereinafter, referred to as D2D communication; device to device communication) refers to a communication method of performing direct data transmission and reception between two adjacent terminals without passing through a base station. That is, the two terminals communicate with each other as a source and destination of data.

There are various discussions about a use case in which such direct communication between terminals can be efficiently used. As an example, the direct communication between terminals may be used for a local media server or the like which provides a large amount of material (eg, a program of a rock concert, information about a performer) to visitors who attend a rock concert.

In this case, each device is connected to the serving cell to perform a telephone call and internet access using a conventional cellular link, but directly from the local media server operating as a counterpart of the D2D communication in a D2D manner. Can send and receive

Meanwhile, the D2D link is not only possible between devices having the same cell as the serving cell but also between devices having different cells as the serving cell. For example, device 3 belonging to the first base station may perform D2D communication with device 6 belonging to the second base station.

Such direct connection communication between terminals includes a centralized D2D communication method and a distributed control method D2D communication method.

In the centralized D2D communication method, when a device that wants to communicate with another device requests a link to a central node (base station in a cellular network) that performs control, and the central node has a counterpart device in the vicinity of the device. A method of allocating radio resources for direct communication between two devices to enable communication between devices. At this time, almost all operations of the device are managed by the central node, and radio resources allocated for the cellular link or another D2D link for the D2D communication may be reused.

The distributed control method of D2D communication is a method of establishing a link in a distributed control method through direct signal exchange between devices without relying on one central control node and exchanging data with peripheral devices directly. The standard for such direct communication between distributed control terminals is the FlashLinQ technology proposed by Qualcomm. FlashLinQ technology corresponds to a synchronous technology based on time division duplexing (TDD).

Many advantages and disadvantages exist in the conventional cellular communication and the above-described D2D communication method. Therefore, ultimately, it is expected that a communication system of a combination of cellular mobile communication and D2D communication described above will become commonplace. However, in the case of the current cellular network, not only the aforementioned D2D communication method of the distributed control method is considered, but also a method of performing the conventional cellular communication and the D2D communication in the cellular network is not provided. Do.

An object of the present invention is to provide a method for operating a base station that enables cellular network-based D2D communication, and to allow a base station to determine whether to perform central control D2D communication and whether to perform cellular link communication.

Another object of the present invention is to provide a method for operating a terminal that enables cellular network-based D2D communication, and to allow the terminal to determine whether to perform distributed control D2D communication and whether to perform central control D2D communication.

Another object of the present invention is a method of operating a terminal that enables cellular network-based D2D communication, and in particular, when the terminal performs distributed control D2D communication based on a radio resource allocated by a base station, synchronization, discovery It provides a method for performing discovery, paging, and traffic procedures.

Another object of the present invention is a method of operating a base station that enables cellular network-based D2D communication, and in particular, when the terminal performs distributed control D2D communication based on a radio resource allocated by the base station, It provides a way to monitor adequacy.

In order to achieve the above object of the present invention, the present invention is a method for operating a base station supporting cellular network-based device to device (D2D) communication, the central control based on the request of at least one terminal or by the determination of the base station The present invention provides a cellular network-based D2D communication method including determining whether to perform D2D communication or cellular link communication, and performing central control D2D communication or cellular link communication based on the determination.

Here, the base station performs the central control D2D communication when a target terminal exists in the same cell or a neighbor cell as a source terminal and the target terminal and the source terminal can directly communicate between the terminals. Can be determined.

In this case, when the target terminal and the source terminal is located in different cells, the base station may be configured to allocate the same radio resource for central control D2D communication with the base station of the neighboring cell through information exchange with the base station of the neighboring cell. have.

In order to achieve the above object of the present invention, the present invention provides a method for operating a terminal supporting cellular network-based D2D communication, the terminal determining whether to perform a central control D2D communication or distributed control D2D communication and the Based on the determination, the terminal performs distributed control D2D communication, or provides a cellular network-based D2D communication method comprising the step of requesting the base station to configure for the central control D2D communication.

Herein, the terminal determines whether to perform the central control D2D communication or the distributed control D2D communication based on the amount of data to be transmitted or received with an adjacent terminal, or based on whether the distributed control D2D communication is congested. Whether to perform the central control D2D communication or the distributed control D2D communication may be determined.

In order to achieve the above object of the present invention, the present invention provides a method for operating a terminal that supports cellular network-based device to device (D2D) communication, and includes a cellular frame timing using a synchronization signal and a broadcast channel from a base station. Extracting system frame number (SFN) information, receiving configuration information for distributed control D2D communication from a base station, based on the cellular frame timing, the system frame number and the configuration information The present invention provides a cellular network-based D2D communication method including obtaining timing for distributed control D2D communication and performing distributed control D2D communication based on the timing for distributed control D2D communication.

Here, the synchronization signal may be a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), and the broadcast channel may be a physical broadcast channel (PBCH).

In this case, the configuration information may be received through system information (SI) or radio resource control (RRC) signaling.

Here, the configuration information includes (a) information for obtaining a start position of distributed control D2D communication from the cellular frame timing and system frame number, and (b) period of discovery, paging and traffic steps for the distributed control D2D communication. And information related to a transmission method for the distributed control D2D communication and information relating to a hash function for generating a connection ID.

Here, in the step of performing the distributed control D2D communication, the terminal in the paging step and traffic step, the transmission power (transmission power) based on the density (density) of the terminal participating in the distributed control D2D communication in the cell Can be controlled.

Here, in the step of performing the distributed control D2D communication, in the discovery step, the terminal selects and uses the Peer Discovery Resource (PDR) resources grouped by the probability of being recovered by the base station in the order of low probability of being recovered. Can be. In this case, the configuration information may include grouping information of PDR resources used in the discovery step of the distributed control D2D communication and information related to selection criteria.

Here, the operation method of the terminal may further include the step of the terminal reporting information related to whether the distributed control D2D communication performance capability and the distributed control D2D communication performance capability is activated to the base station.

Here, the operation method of the terminal may further include the step of the terminal reporting the success of data transmission through the distributed control D2D communication to the base station.

Here, in the operation method of the terminal, if the terminal fails to transmit data through distributed control D2D communication, or if a delay occurs above a predetermined reference, reporting whether the failure or the delay occurs to the base station It may further comprise a step.

In order to achieve the above object of the present invention, the present invention provides a method for operating a base station supporting cellular network-based D2D communication, the distributed control D2D communication performance and distributed control D2D communication performance capability from at least one terminal Provided is a cellular network-based D2D communication method comprising receiving information related to activation and estimating the number of terminals participating in distributed control D2D communication and a required resource amount based on the information.

Here, the information related to whether to activate the distributed control D2D communication performance capability received from the terminal may include information specifying whether to participate in the discovery phase, participation in the paging / traffic phase.

 Here, the operation method of the base station may further include the step of receiving a report of the success of data transmission from the terminal successful data transmission through distributed control D2D communication.

Here, the operation method of the base station further comprises the step of receiving a report whether the failure or the delay occurs from at least one terminal that fails to transmit data through a distributed control D2D communication, or a delay exceeding a predetermined reference It can be included as.

By using the method of directly connecting communication between terminals in the cellular network according to the present invention as described above, it is possible to configure the cellular communication, the central control D2D and the distributed control D2D communication flexibly and selectively in the cellular network.

In addition, by specifically providing a synchronization, discovery, paging, and traffic method for enabling D2D communication in a cellular network, distributed control, particularly under a 3GPP LTE mobile communication network. Enables D2D communication. This enables efficient resource management.

1 is a conceptual diagram illustrating the concept of a cellular network-based terminal-to-terminal direct communication.
2 is a conceptual diagram illustrating a communication operation procedure of the distributed control D2D communication method.
3 is a timing diagram illustrating a synchronous timing structure of a distributed control D2D communication operation procedure.
4 is a conceptual diagram illustrating a paging step of a D2D communication operation procedure of a distributed control method.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

A "terminal" used in the present application includes a mobile station (MS), a user equipment (UE), a user terminal (UT), a wireless terminal, an access terminal (AT), a terminal, a subscriber unit, A subscriber station (SS), a wireless device, a wireless communication device, a wireless transmit / receive unit (WTRU), a mobile node, a mobile, or other terminology. Various embodiments of the terminal may be used in various applications such as cellular telephones, smart phones with wireless communication capabilities, personal digital assistants (PDAs) with wireless communication capabilities, wireless modems, portable computers with wireless communication capabilities, Devices, gaming devices with wireless communication capabilities, music storage and playback appliances with wireless communication capabilities, Internet appliances capable of wireless Internet access and browsing, as well as portable units or terminals incorporating combinations of such functions However, the present invention is not limited thereto.

A 'base station' used in the present application generally refers to a fixed or mobile point communicating with a terminal and includes a base station, a Node-B, an eNode-B, a BTS a base transceiver system, an access point, a relay, and a femto-cell.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

1 is a conceptual diagram illustrating the concept of a cellular network-based terminal-to-terminal direct communication.

Referring to FIG. 1, a cellular communication network including a first base station 110 and a second base station 120 is configured.

At this time, the terminal 1 to terminal 3 (112, 113, 114) belonging to the cell 111 generated by the first base station 110 is to communicate through a normal access link (cellular link) through the first base station In addition, the terminal 4 115 and the terminal 5 116 belonging to the first base station directly perform data transmission and reception with each other without passing through the base station.

Referring back to FIG. 1, the D2D link is not only possible between devices having the same cell as the serving cell but also between devices having different cells as the serving cell. For example, the terminal 3 114 belonging to the first base station 110 may perform D2D communication with the terminal 6 122 belonging to the second base station 120.

Meanwhile, the terminal 4 115, the terminal 3 114, and the terminal 6 116, which perform direct communication between terminals, are configured to establish a D2D communication link with the first base station 110, the second base station 120, and the D2D communication. It can be configured to exchange control signals for allocation of available resources and the like under the control of the base station, which can be defined as cellular network-based D2D communication.

2 is a conceptual diagram illustrating a communication operation procedure of the distributed control D2D communication method.

Referring to FIG. 2, the communication operation procedure of the distributed control D2D communication method is largely performed in a synchronization step 210, a discovery step 220, a paging step 230, and a traffic communication step. And 240.

As a representative example of such a distributed control method of the D2D communication method, the FlashLinQ method proposed by Qualcomm exists, and the FlashLinQ also includes a communication operation procedure as described above. However, the operation procedure of the distributed control D2D communication method described below may be a general operation procedure of the synchronous distributed control D2D communication method and is not necessarily limited to the FlashLinQ technology.

In the synchronization step, each device participating in the D2D communication acquires synchronization using an appropriate reference signal to derive timing for a time interval during which discovery, paging, and traffic communication is performed.

3 is a timing diagram illustrating a synchronous timing structure of a distributed control D2D communication operation procedure.

Referring to FIG. 3, the acquired device performs an operation related to discovery in a discovery period 310, an operation related to paging in a paging slot 320, and a traffic slot. In step 330, only an operation for traffic data exchange is performed. This is a characteristic essential procedure of synchronous distributed control D2D communication, basically, to minimize power consumed for discovery and paging by devices participating in D2D.

The discovery step is for discovering another device capable of D2D communication. That is, each device needs information to announce its existence using Peer Discovery Resource (PDR) that is not used by other devices ("expression"; for example, created using device ID and application ID). It is a step of identifying which peers are around each device by transmitting the data and receiving information transmitted by other devices.

The paging phase is a procedure for establishing a connection with an adjacent device by a device that needs to be transmitted or received after discovery. Obtaining a separate ID, that is, a connection ID (CID), to participate in the connection establishment process in the traffic phase. It is a step for. In this case, the CID may be a temporary and local value.

4 is a conceptual diagram illustrating a paging step of a D2D communication operation procedure of a distributed control method.

Referring to FIG. 4, the paging stage may be subdivided into a CID broadcast stage 321, a paging request stage 322, and a paging response stage 333. Through the paging process, the device (pager) requesting paging and the device (pagee) responding to paging secure the same CID.

In the CID broadcast step, a device that acquires a CID and uses it to continue to participate in link scheduling in a subsequent traffic phase broadcasts a CID using resources that counter this CID. During this period, all devices except the device broadcasting the CID perform a reception operation.

In the paging request step, each pager wanting traffic communication generates a CID using its mark, the mark of the counterpart device, and the current time (using a hash function), and the generated CID is a CID broadcasting section. If the CIDs do not match, the pager transmits a paging request signal using the radio resource corresponding to the CIDs. All other devices except for the device that transmitted the paging request signal perform an operation for checking whether each CID is received during this period.

In the paging response step, all devices except pager generate CIDs using their private expressions and their counterparts, and also public expressions. That is, the pagee generates the same CID using the same marker information as the pager and checks whether the CIDs received in the paging request section and the CIDs generated by the pager are identical, and there is a matching CID, which is received in the CID broadcast section. If the CID does not match, the page transmits a paging response using the resource corresponding to the CID.

This is because the CIDs received by the pager and pagee in the CID broadcasting section may be different, thereby eliminating the risk that different device pairs generate the same CID and move to the traffic stage.

The traffic phase is a step in which data transmission and reception are performed, and all devices that have secured the CID during the paging process participate in distributed scheduling, and the devices that have the right to transmit and receive perform transmission and reception of data.

The interval in which the traffic step is performed is subdivided into link scheduling 331, pilot interval 332, CQI interval 333, data interval 334, and ACK interval 335.

In the link scheduling (or connection scheduling) section, signals are exchanged to transmit and receive data in a data section in a distributed manner without control of the central node while allowing devices to spatially reuse radio waves as efficiently as possible without interfering with each other. This is the interval for scheduling. That is, devices having data to send repeatedly participate in link scheduling during the traffic period, and the link scheduling period is composed of a Request to Send (RTS) and a Clear to Send (CTS) period.

Each CID is mapped to a pair of radio resources of RTS and CTS. Radio resources of RTS and CTS are prioritized in scheduling according to their location, and the selection of a pair of radio resources is pseudo randomized based on CID and newly selected for each traffic slot for fairness between CIDs. do.

A device with data to send transmits a signal using a radio resource corresponding to its own CID in the RTS section, and the receiving device transmits a signal to the same CID section in the CTS section when the received signal to interference ratio (SIR) is above a certain level. The CTS signal is transmitted using the corresponding radio resource. If the level is lower than the predetermined level, the CTS transmission is abandoned.

The device sending the RTS may not receive a CTS signal on a resource corresponding to the same CID (receive level is below a certain level), or may cause a certain level of interference on higher priority links (determined by CID). If it is determined that the traffic data transmission is abandoned and does not participate in the process from the pilot to the ACK.

Combining the pilot and CQI intervals, it can be referred to as a rate scheduling interval. A transmission device that secures radio resources in a distributed manner through a connection scheduling process sends a pilot signal, and a reception device measures a channel using the appropriate CQI. Generates information and responds to the sending device.

In the data and ACK interval, the transmitting device transmits data according to the CQI information and the receiving device responds with an ACK.

The FlashLinQ scheme proposed by Qualcomm aims only at D2D communication of a distributed control scheme that operates independently, and is not considered to be combined with a conventional cellular network. Accordingly, an object of the present invention is to provide a method for enabling D2D communication in a cellular network such as 3GPP LTE.

Cellular network D2D  Communication Performance  How to decide

In traditional cellular networks, devices are configured to exchange data only with base stations. However, in the cellular network, in addition to such a function, it may be necessary to support direct communication between devices.

In this case, the cellular network-based D2D communication may include a central control method and a distributed control method.

First, the cellular network-based centralized D2D communication may refer to a cellular network-based D2D communication in which link setting and resource allocation are dynamically performed by a base station whenever link setting including scheduling is required. On the other hand, the cellular network-based distributed control D2D communication is specified by fixed or semi-fixed radio resources separate from the radio resources for the cellular link for discovery, paging, and traffic communication, and distributed Cellular networks configured to participate in control D2D communication use this resource to minimize the dynamic control of the base station and to establish a link in a distributed control manner through direct signal exchange between devices and to use it to exchange data directly with neighboring devices. It may mean based D2D communication.

Meanwhile, if both the centralized D2D communication and the distributed control D2D communication can be supported in the cellular network, the cellular communication, the centralized D2D communication, and the distributed control D2D communication may be selectively operated depending on the situation. have.

In a cellular network, D2D communication of a central control or a distributed control method may be determined according to a determination of a network or a device.

First, the network may be configured to determine and control either cellular communication or centralized D2D communication upon a cellular link establishment request of the device, and may be configured to perform centralized D2D communication according to the request of the device. The network may be configured not to determine whether to select distributed control D2D communication, and as mentioned above, if the network allocates resources used for distributed control D2D fixedly or semi-fixed, then The distributed control of the D2D operation is made under the determination of the device.

In this case, the network may be configured to establish a central control D2D communication link setting, otherwise, establish a cellular link if the destination device is located in the same cell or an adjacent cell as the source device and direct communication between the source and destination devices is possible. . In this case, for centralized D2D communication between devices in neighboring cells, the same radio resource allocation is required through cooperation (information exchange) with neighboring base stations.

The network may also be configured to instruct centralized D2D communication at its discretion even when there is no link establishment request from the device.

Meanwhile, the device may participate in distributed control D2D communication or request a central control D2D communication link establishment in consideration of the amount of data to be exchanged (or predicted to be exchanged) with the peripheral device.

In this case, the device may determine whether to participate in distributed control D2D communication or to request a base station to establish a central control D2D communication link according to its own decision, except for devices that do not have or do not intend to participate in distributed control D2D communication link. All devices shall continue to participate in the discovery process of distributed control D2D communication or as necessary.

The device participates in the paging and traffic communication process of distributed control D2D communication when there is a small amount of data to be exchanged (or predicted to be exchanged) and exchanges (or exchanges) when there is data to be transmitted to an adjacent device. If the amount of data (predicted) or the amount of data is small but congestion occurs in the distributed control D2D communication, it may be configured to request the base station to allocate the centralized D2D link.

Cellular Network Based Distributed Control D2D  Communication method

Hereinafter, the considerations in the synchronization, discovery, paging, and traffic stages when the D2D communication is supported in the cellular network will be described. In particular, in the present invention, a method of supporting distributed control D2D communication in the 3GPP LTE cellular network will be described first. However, the technical idea mentioned below is implemented in similar cellular networks using the same / similar technology elements as in the 3GPP LTE scheme. This will be possible.

1) Considerations in the Synchronization Phase

As mentioned above, all devices participating in distributed control D2D communication need synchronization (synchronous distributed control D2D communication).

In this case, in the cellular network, devices may be configured to synchronize by using a synchronization signal or a broadcast signal provided by a base station.

For example, in the case of 3GPP LTE, each device may secure synchronization using a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) and a physical broadcast channel (PBCH) of a base station. For example, the system frame number (SFN) can be represented by 10 bits by combining 8 bits delivered by a master information block (MIB) and 2 bits obtained through blind decoding of a synchronization signal (one period is 210 * 10 ms. = 10240 ms = 10.24 sec). The cellular frame timing, SFN, and configuration information provided by the network (base station) are used to obtain the synchronization timing (D2D communication super frame, sub super frame, frame, slot timing, etc.) necessary for distributed control D2D communication. Allow devices to operate.

2) Considerations at the Discovery, Paging, and Traffic Stages

Resources for distributed control D2D communication may be made by one or a combination of the following two methods.

First, in a frequency division multiplexing (FDM) scheme, some bands are designated for distributed control D2D communication in one subframe, and the remaining partial bands are scheduled for cellular link use.

Secondly, TDM (Time Division Multiplexing) is a method of designating a separate subframe for distributed control D2D communication.

On the other hand, the resource configuration for distributed control D2D communication is preferably applied equally in all cells, which is to enable distributed control D2D communication between devices located in adjacent cells.

In a cellular network, a role that a network must play in order to support distributed control D2D communication includes managing configuration for distributed control D2D communication (ie, D2D timing configuration, radio resource configuration, transmission method, distributed control D2D). Various parameters related to communication), distributed control D2D communication resources management (change of resource amount, monitoring the appropriateness of resource amount) is required. This is also necessary for distributed control D2D communication charging data collection.

1) Management of configuration information related to distributed control D2D communication

Content included in configuration information related to distributed control D2D communication may include all or part of the following contents as necessary.

a) Timing structure for distributed control D2D communication. Since the device knows the cellular frame timing and SFN, the SFN and subframe offsets of the cellular network indicating the start of the subsuperframe (including the start of the frame, if necessary) for D2D communication, and the D2D communication subsuperframe at that time ( And frame) so that each device can secure D2D communication.

b) the frame structure of distributed control D2D communication (location, stage, etc. of each step such as discovery, paging, traffic communication, etc.) and the composition and quantity of radio resources for each step of the D2D.

c) Transmission method and parameters of distributed control D2D communication (transmission method for each stage such as discovery, paging, traffic communication, and other parameters related to distributed control D2D communication, such as yielding parameters).

d) Information related to a hash function (hash function for generating a CID) (may be configured to be implicitly delivered or explicitly delivered according to resource related configuration information).

The above-described information may be broadcast in system information (SI) in a cell-specific manner and may be transmitted to the terminal through RRC (Radio Resource Control) signaling in a UE-specific manner (UE-specific manner). It may be delivered. Alternatively, signaling may be performed through a combination of both.

In addition, the above-described configuration information for distributed control D2D communication of another operator network may also be transmitted to the device through SI broadcasting, RRC signaling, or a combination thereof so that each device may participate in distributed control D2D communication of another operator network. Must be communicated.

Next, if the amount of radio resources per cell for distributed control D2D communication is similar to the density of D2D devices per cell, it may be desirable to specify the same amount of radio resources for each cell and apply the same configuration. However, if the density of distributed control D2D devices differs from cell to cell, it is desirable to vary the amount of radio resources allocated to each cell.However, in this case, it is difficult to solve such problems as interference between cellular links and distributed D2D communication resources in a cell boundary region. exist. Therefore, a method of designating a radio resource for each cell in the same manner and adjusting some configuration using SI and / or RRC signaling for each cell may be used.

First, in the discovery phase, normally all devices participate in the discovery process, but if the density of the device increases, the configuration is adjusted to reduce the number of transmitting devices. In this case, only devices that need to transmit, such as a device that is willing to provide a service or actively receive a service, or a device that wants to comply with a request of a counterpart device, are instructed to participate in discovery transmission. At this time, the device which started the transmission at the request of the counterpart device stops the transmission after a certain time. In contrast, all devices participating in the D2D communication continue to receive.

Secondly, in the paging step, the transmission parameters (eg, transmission power control) for each cell are changed according to the density of the device. In other words, it is possible to reduce the range and increase spatial reuse by lowering the transmission power.

Third, even in the traffic stage, the transmission parameters (eg, transmission power control) for each cell are changed according to the device density. In other words, it is possible to reduce the range and increase spatial reuse by lowering the transmission power.

2) Resource quantity management for D2D communication

On the other hand, if the amount of radio resources for distributed control D2D communication is changed, there may be a problem and solution that appears during the transition (transition) process.

First, in the discovery phase, in order to reduce some of the allocated radio resources, the PDR resources may be divided and managed. That is, if a device divides discovery resources into two or more groups and requires a PDRID, the device usually selects a PDRID from a resource group that is unlikely to be recovered by a base station, and the number of selectable PDRIDs of the group is less than or equal to a certain number. Can only be configured to select from other groups' PDRIDs. Alternatively, a resource group that is likely to be recovered by the base station may be configured to have a low selection probability, and a resource having a low probability of being recovered may have a higher selection probability. Meanwhile, the configuration information described above may be configured to include grouping information of resources and necessary parameters (for example, PDR resource group selection criteria and selection probability of each group) in preparation for the transition process when the amount of resources is changed.

When the amount of discovery resources is increased, the above-described method may be applied as it is. When a portion of the discovery resources is recovered, the device transmitting the mark using the resources recovered by the base station may be configured to continue the transmission by selecting a PDRID not used in the resource group that is not recovered.

Second, when the number of CIDs decreases during CID broadcasting in the paging stage, CIDs outside the range may be configured to give up broadcasting.

The network needs to monitor the adequacy of radio resources related to distributed control D2D communication in order to properly configure the resources. Hereinafter, a method for monitoring adequacy of radio resources related to distributed control D2D communication will be described.

First, a method for collecting distributed control D2D communication capability and activation state information of a function of devices in a connected state, the device configured to report distributed control D2D communication capability and whether the capability is activated when the device connects to a cell. can do.

In this case, the device may participate only in discovery or may participate in all distributed control D2D communication processes. In addition, it is possible to report when the activation state is changed by the user.

This allows the network to know the number of connected state devices participating in distributed control D2D communications (more accurately discovery and paging / traffic).

The second is to monitor the adequacy of radio resources for discovery, using the D2D communication capability and activation state information of the connected state devices described above, the number of devices (including devices in the idle state) and the amount of resources required to participate in the discovery. Can be configured to estimate.

Third, monitoring the adequacy of radio resources for paging, using the D2D communication capability and activation state information of the connected state devices described above, the number of devices (including devices in the idle state) and the amount of resources required to participate in the paging. Can be configured to estimate. Or, it may be configured to estimate the appropriate amount of resources and the amount of resources needed using the collected data according to the resource adequacy monitoring method for traffic to be described later.

Fourth, by monitoring the adequacy of radio resources for the traffic, a device that succeeds in data transmission through the distributed control D2D communication can be reported to the network to use it to monitor the billing data generation and D2D traffic amount. In this case, a device that succeeds in data transmission may reduce the overhead of signaling by reporting the data when the data is transmitted in an appropriate period or a predetermined amount.

The device may be configured to report to the network (base station) when the device cannot continuously transmit data for a predetermined time due to continuous failure in securing channel usage rights in link scheduling, or when the latency is greater than a certain degree. In this case, such a report may be configured to report all devices corresponding to or report only devices previously selected by the base station. If it is determined that the resource for the traffic is insufficient, that is, congestion, the device may request the base station to establish a centralized D2D link, and the network may allocate more resources for distributed control D2D communication if such a situation persists. It may also be possible to change the configuration to assign it.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

110: first base station
120: second base station
112, 113, 114, 115, 116, 122: terminal

Claims (19)

  1. An operating method of a base station supporting cellular network based device to device (D2D) communication,
    Determining whether to perform central control D2D communication or cellular link communication based on a request of at least one terminal or by the determination of the base station; And
    Based on the determination, performing central control D2D communication or cellular link communication.
  2. The method according to claim 1,
    The base station determines that the target terminal is present in the same cell or neighbor cell as the source terminal and the target terminal and the source terminal to perform the central control D2D communication when the terminal can directly communicate with the terminal. Cellular network based D2D communication method.
  3. The method according to claim 2,
    When the target terminal and the source terminal is located in different cells, the base station allocates the same radio resource for the central control D2D communication with the base station of the neighboring cell through information exchange with the base station of the neighboring cell. Way.
  4. An operating method of a terminal supporting cellular network based device to device (D2D) communication,
    Determining, by the terminal, whether to perform central control D2D communication or distributed control D2D communication; And
    Based on the determination, the terminal performing distributed control D2D communication or requesting a base station to configure for central control D2D communication.
  5. The method of claim 4,
    The terminal,
    Determining whether to perform the central control D2D communication or the distributed control D2D communication based on the amount of data to be transmitted or received with an adjacent terminal;
    And determining whether to perform the central control D2D communication or the distributed control D2D communication based on whether the distributed control D2D communication is congested.
  6. An operating method of a terminal supporting cellular network based device to device (D2D) communication,
    Extracting cellular frame timing and system frame number (SFN) information using the synchronization signal and the broadcast channel from the base station;
    Receiving configuration information for distributed control D2D communication from a base station;
    Obtaining timing for distributed control D2D communication based on the cellular frame timing, the system frame number, and the configuration information; And
    And performing distributed control D2D communication based on the timing for the distributed control D2D communication.
  7. The method of claim 6,
    The synchronization signal is a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), and the broadcast channel is a cellular network based D2D communication method, characterized in that the PBCH (Physical Broadcast Channel).
  8. The method of claim 6,
    The configuration information is a cellular network based D2D communication method received through system information (SI) or Radio Resource Control (RRC) signaling.
  9. The method of claim 6,
    The setting information
    (A) information for obtaining a start position of distributed control D2D communication from the cellular frame timing and system frame number, (b) information related to the period of discovery, paging, and traffic phase for the distributed control D2D communication, (c) And (d) at least one of information related to a transmission method for distributed control D2D communication and (d) information related to a hash function for generating a connection ID.
  10. The method of claim 6,
    In the step of performing the distributed control D2D communication,
    The terminal controls the transmission power (transmission power) based on the density (density) of the terminal participating in the distributed control D2D communication in the cell in the paging phase and traffic phase.
  11. The method of claim 6,
    In the step of performing the distributed control D2D communication,
    The UE selects and uses a PDR (Peer Discovery Resource) resource grouped by the probability of being recovered by the base station in the discovery step in the order of low probability of being recovered.
  12. The method of claim 11,
    Wherein the configuration information includes grouping information of PDR resources used in the discovery step of the distributed control D2D communication and information related to selection criteria.
  13. The method of claim 6,
    And reporting, by the terminal, information related to whether the distributed control D2D communication performance capability and the distributed control D2D communication performance capability are activated to the base station.
  14. The method of claim 6,
    And reporting, by the terminal, the success of data transmission through distributed control D2D communication to the base station.
  15. The method of claim 6,
    If the terminal fails to transmit data through a distributed control D2D communication, or if a delay occurs above a predetermined reference, the cellular network based further comprising the step of reporting the failure or whether the delay occurs to the base station D2D communication method.
  16. An operating method of a base station supporting cellular network based device to device (D2D) communication,
    Receiving information related to whether the distributed control D2D communication performance capability and the distributed control D2D communication performance capability are activated from at least one terminal; And
    And estimating the number of terminals participating in distributed control D2D communication and the required amount of resources based on the information.
  17. 18. The method of claim 16,
    The information regarding whether activation of the distributed control D2D communication performance capability received from the terminal includes information indicating whether to participate in the discovery phase and whether to participate in the paging / traffic phase.
  18. 18. The method of claim 16,
    Cellular network-based D2D communication method further comprising the step of receiving a report of the success of the data transmission from the terminal successful data transmission through the distributed control D2D communication.
  19. 18. The method of claim 16,
    Cellular network-based D2D communication method further comprising the step of reporting whether the failure or the delay occurs from at least one terminal that fails to transmit data through a distributed control D2D communication, or a delay exceeding a predetermined reference .
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