Method and apparatus for device-to-device communication

In accordance with an example embodiment of the present invention, there is provided an apparatus, comprising at least one processing core configured to determine an opportunity for device-to-device, D2D, communication, and at least one transmitter configured to cause transmitting of a D2D communication request, wherein the D2D communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of D2D communication that is requested. The indicated type may comprise D2D communication with no fallback to cellular connectivity, wherein such a D2D communication can be established without involving a core network, CN.

TECHNICAL FIELD

The present application relates generally to communicating between devices using radio resources, and managing radio resources for such communication.

BACKGROUND

Cellular communication networks typically comprise a radio access network comprising a set of base stations, and a core network comprising nodes tasked with managing the system and routing data to and from further networks, in some networks, the radio access network comprises in addition to base stations base station controlling nodes, such as for example radio network controller, RNC, nodes in a wideband code division multiple access, WCDMA, communication system. Another example of a base station controlling node is a base station controller, BSC, controller node in a global system for mobile communications, GSM, communication system.

Communication in a cellular communications network typically traverses the network, for example where a cellular telephone is called from a landline, the call will arrive from the landline network in a gateway node comprised in the core network of the cellular network, and be routed from there to the radio access network, for delivery from a base station in the radio access network, via a radio interface, to the called cellular telephone. Likewise where a cellular telephone calls another cellular telephone of the same network, the call may be routed via the radio access network and core network to the called cellular telephone.

On the radio interface, cellular communications may use radio resources allocated to such use, wherein the networks may manage use of the radio resources so as to allow users access to the system in an optimal way. Managing the radio resources may comprise balancing availability and quality of service, since the allocated radio resources may not be sufficient to provide maximal service continually to all users. The users may be further constrained by access to energy when their cellular telephones, or more generally terminals, are battery-powered.

In some cases, use of radio resources may be optimized by terminals of a cellular communications network communicating with each other directly in the sense that they receive radio signals from each other, rather than from a base station. In other words, information may be exchanged between the terminals so that the information isn't routed via a base station, rather the information is transmitted from a first terminal and received directly from the radio interface in a second terminal.

Direct communication between terminals may use radio resources also used when communicating with a base station, or alternatively direct communication may use different radio resources. When the same radio resources are used the cellular communications network may have an interest in at least partially controlling the direct communication, since resources used in the direct communication may become unavailable for other communication in the cellular communications network. Where different resources are used, the cellular communications network may also have an interest in at least partially controlling the direct communication, for example where interference is possible with resources of the cellular communications network, or where the network wants to charge the terminals for the direct communication, or for other reasons.

SUMMARY

According to a first aspect of the present invention, there is provided an apparatus, comprising at least one processing core configured to determine an opportunity for device-to-device communication, and at least one transmitter configured to cause transmitting of a device-to-device communication request, wherein the device-to-device communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of device-to-device communication that is requested.

According to a second aspect of the present invention, there is provided a method, comprising determining an opportunity for device-to-device communication, and causing transmitting of a device-to-device communication request, wherein the device-to-device communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of device-to-device communication that is requested.

According to a third aspect of the present invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least receive, using a cellular communication technology, device-to-device communication request from a first user equipment, and process the device-to-device communication request locally without involving a core network, wherein the device-to-device communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of device-to-device communication that is requested.

According to a fourth aspect of the present invention, there is provided a method, comprising receiving, using a cellular communication technology, a device-to-device communication request from a first user equipment, and processing the device-to-device communication request locally without involving a core network, wherein the device-to-device communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of device-to-device communication that is requested.

According to further aspects of the present invention, there are provided computer programs configured to cause methods in accordance with the second and fourth aspects of the present invention to be performed.

DETAILED DESCRIPTION OF THE DRAWINGS

An example embodiment of the present invention and its potential advantages are understood by referring toFIGS. 1 through 6of the drawings.

FIG. 1illustrates a first system capable of supporting at least some embodiments of the invention. Illustrated is terminal110, which will hereinafter be referred to as mobile110. Mobile110may comprise, for example, a smart phone, a tablet or laptop computer, cellular phone, personal digital assistant, machine for machine-to-machine, M2M, automated device or another similar apparatus. Mobile110may be a user equipment, UE, in the sense of wideband code division multiple access, WCDMA, or long term evolution, LTE, standards defined by the third generation partnership project, 3GPP, for example.FIG. 1illustrates also mobile120, which may be a similar device as mobile110in the sense of being a user equipment or terminal of the cellular network ofFIG. 1. While the term “mobile” is used herein, it is understood that in some embodiments at least some of these devices may in fact be stationary.

FIG. 1also illustrates base station130and base station140. Base station130and base station140may be essentially similar, for example they may act as base stations in the same system. In some embodiments, base station130and base station140are base stations comprised in a WCDMA or LTE cellular system. As a terminological point, a WCDMA base station may be known as a node-B. Similarly a LTE base station may be known as an eNB. Mobile110may be communicatively connected to base station130via wireless link111. Wireless link111may operate in accordance with a defined standard, for example WCDMA or LTE, or where mobile110is capable of communicating with wireless local area network, WLAN, access points wireless link111may operate in accordance with WLAN standards. Also other standards, all of which cannot be named here for the sake of conciseness, are possible. Wireless link111may comprise an uplink for conveying information from mobile110to base station130. Wireless link111may comprise a downlink for conveying information from base station130to mobile110. The uplink and/or downlink of wireless link111may operate in a time division multiple access, TDMA, frequency-division multiple access, FDMA, code-division multiple access, CDMA, orthogonal frequency division multiple access, OFDMA, manner or in a manner that is a combination of at least two of the foregoing multiple access methods. The uplink and/or downlink of wireless link111may operate in a time division multiplexing, TDD or frequency division multiplexing, FDD manner.

Mobile120may be configured to communicate with base station130via wireless link121, which may like wireless link111comprise an uplink and downlink, and operate in accordance with TDMA, FDMA, CDMA and/or OFDMA. Mobiles110and120are illustrated as being inside a cell coverage area139of base station130, in other words they are inside a coverage area of a cell controlled by base station130. Mobiles110and120may be attached to base station130in the sense that a cell controlled by base station130is a serving cell for these mobiles.

Base station130may be configured to communicate with core network node150via connection131. Connection131may comprise a wire-line connection, or alternatively connection131may be at least in part wireless. Core network node150may perform functions related to controlling the cellular communications network, such as switching, acting as a gateway, a subscriber information repository, an authentication center or other core network function. The core network may comprise further core network nodes, which are not illustrated. Core network node150may communicate with such further core network nodes via connection151, for example. In an LTE network, connection131may comprise an S1 interface.

Base station130may be configured to communicate with base station140via connection135, which may be a wire-line or wireless connection. In an LTE network, connection135may comprise a X2 interface, or a modified X2 interface. Base station140may be configured to communicate with core network node150via connection141. Base station140may control a cell, the coverage area of which is illustrated inFIG. 1as149.

Mobiles120and130may be configured to engage in direct communication over wireless link115. Such direct communication between two terminals may be referred to as device-to-device communication. Device-to-device communication may thus comprise that information is transmitted from mobile110using a radio transmitter, and received in mobile120using a radio receiver, such that radio frequency energy is received in mobile120that was transmitted from mobile110, and the transmitted information is not relayed via a base station. Wireless link115may employ radio resources used in communication between mobiles and base station130, or alternatively wireless link115may employ different radio resources.

Radio resources may be defined in terms of at least one of frequency, time, spreading codes and space. When radio resources are defined in terms of frequency, frequency channels or bands may be defined. Users may transmit simultaneously, but without interference since the transmissions will occur on non-overlapping frequencies. When radio resources are defined in terms of time, time-slicing, timeslots or time frames may be defined, for example to allow a frequency channel to be shared between users such that the users don't interfere with each other since their transmissions don't occur simultaneously. When radio resources are defined in terms spreading codes, users may be allowed to transmit simultaneously on the same frequency band. Interference in this case is controlled by allocating orthogonal spreading codes to the transmissions. When radio resources are defined in terms of space, radio transmissions may be allocated in a directional and/or locational sense, allowing transmitters to transmit on the same frequency at the same time without producing interference due to physical separation between the transmissions, which may involve beamforming techniques. An example of defining radio resources in terms of space is a cellular communications network employing a frequency re-use pattern, wherein the same frequencies are used in cells that are not adjacent to each other. Another example is a sectorized base station. Radio resources employed by wireless links111,121and/or115may be defined in terms of at least one of frequency, time, spreading codes and space.

Device-to-device, D2D, communication may exist in at least two different types. A first type of D2D communication comprises D2D communication that is configured with a backup cellular capability. Such a D2D communication can be switched to a cellular connection between the participating devices in case the devices move away from each other, or the D2D connection between then is for another reason severed. For example, where mobile110calls mobile120to effect bidirectional D2D voice communication, the communicating users may want the call to continue, even in case the user of mobile120boards a bus which transports mobile120to another area. In this case, core network node150may be made aware of the D2D communication, and responsive to receiving a report from a mobile participating in the D2D communication that the D2D communication connection is severed, core network node150may be configured to page the participating devices and cause a cellular connection to be formed between the participating devices. In effect, the devices can fallback to a cellular connection. For example, core network node150may be configured to cause a voice call to be created between mobiles110and120responsive to receiving a report from mobile110that it can no longer communicate with mobile120using a D2D communication. Core network node150, which may already be aware of the existence and type of D2D communication between the mobiles before the D2D connection is broken, can relatively seamlessly restore the connection via the cellular network as it may have followed the location of both mobiles during the D2D communication.

A second type of D2D communication comprises D2D communication that is not configured with a backup cellular capability. For example, where mobile120is an advertising unit configured to provide information on special offers of a restaurant to nearby mobiles, or information concerning an amount of fuel available in a fuel tank, or more generally any information that has local scope, a fallback to a cellular connection could be unnecessary since a mobile moving out of range of D2D communication would be unlikely to be able to benefit from the information available via the D2D connection. In some embodiments where mobile120is configured to provide locally relevant information, mobile120is not strictly mobile in the sense that it would move, rather it may be seen as a user equipment or device that may be stationary.

A mobile may determine that a D2D communication opportunity exists in various ways. For example, a mobile may receive a beacon transmission from another mobile, the beacon transmission comprising information on available D2D communication. The information may comprise, for example, at least one of an identity of the beaconing device/mobile, D2D radio resources to be used, a D2D communication technology to be used and metadata on information that can be obtained via D2D communication. A beacon may be transmitted by broadcasting, without the beacon being directed to or intended for any recipient in particular. Alternatively or additionally, a mobile may determine that a D2D communication opportunity exists by receiving from a network node an information message indicating that a D2D communication opportunity exists in the present location of the mobile. For example, the mobile may have subscribed to receive such messages, responsive to which the network node may follow the location of the mobile and compare it to known locations of D2D communication opportunities, and responsive to determining that the mobile is sufficiently near such an opportunity, trigger the sending of the message. Such a network node may comprise, for example, a base station or a core network node.

A beacon received from another mobile can be used to determine an estimate of pathloss between the mobiles. The mobile receiving the beacon can measure a received signal strength of the received beacon and compare it to a known transmit power to estimate, how much energy was lost in transmission to determine the pathloss estimate. The receiving mobile may know the transmit power from the beacon, wherein the beacon may comprise an indication of a transmit power used to transmit the beacon or the receiving mobile may know that all beacons are transmitted using a preconfigured transmit power level. The receiving mobile may know the preconfigured transmit power level from an industry specification, or it may be received from a base station controlling a cell where the receiving mobile finds itself, for example.

Upon determining that an opportunity for D2D communication exists, a mobile has the option of initiating a request for D2D communication. A mobile may be configured to initiate the request responsive to determining that an opportunity exists, or alternatively a mobile may be configured to initiate the request when at least one further condition is met, in addition to the opportunity being determined to exist. Examples of further conditions may include a user accepting a prompt, the mobile being configured to seek a certain kind of information and the determining being accomplished in a certain way, for example by network message or from a beacon. In some embodiments, the mobile may be configured to seek information on restaurants or hair salon offers and responsive to receiving metadata that a D2D communication opportunity may provide such information, the mobile may be configured to initiate the request for D2D communication, optionally after prompting a user to accept.

Mobile110may be configured to initiate the request for D2D communication by signaling, over wireless link111, to base station130. The request may comprise an estimate of link quality, such as for example an indication of pathloss determined as described above. Base station130may responsive to receiving the request for D2D communication ask mobile120, identified in the request, for acceptance over wireless link121, and responsive to mobile120indicating over wireless link121acceptance D2D communication with mobile110, base station130may be configured to allocate radio resources to D2D communication between mobile110and mobile120. Allocating radio resources may take into account a pathloss estimate received in the request from mobile110. Taking the pathloss estimate into account may comprise setting a maximum transmit power accordingly, or allocating enough spectrum band to allow the mobiles to communicate, in view of the pathloss, or more generally link quality. The allocating may comprise informing at least one of mobile110and mobile120of the allocated resources. Where the D2D communication is to be configured with backup cellular capability, base station130may be configured to coordinate the establishment of the D2D communication with core network node150, to enable the cellular fallback option in case D2D communication between the mobiles fails. Where backup cellular capability is configured, the D2D communication may be monitored in core network node150until the D2D communication ends, at which point at least one of mobile110and mobile120may be configured to inform base station130of the ending of the D2D communication. Base station130may inform core network node150of the ending of the D2D communication by signaling via connection131. Responsive to learning that the D2D communication between mobile110and mobile120has ended, core network node150may cease monitoring the D2D communication.

In some embodiments, core network node150is configured to communicate with further core network nodes in connection with establishing the D2D communication, for example to cause charging, authentication and/or authorization to occur. For example, core network node150may inquire from a further core network node, if both mobiles110and120are associated with subscriptions that allow D2D communication. If at least one of the subscriptions doesn't allow D2D communication, core network node150may be configured to inform base station130that the D2D communication request is to be denied, and responsively base station130may refrain from allocating radio resources to the D2D communication. Therefore, in general where the D2D communication is to be configured with backup cellular capability, a signaling procedure may be triggered in and/or with the core network.

Where backup cellular capability is not needed, base station130may be capable of initiating, maintaining and terminating the D2D communication either alone, or in co-operation with other base stations without involving the core network. In some embodiments, base station130is capable of initiating, maintaining and terminating the D2D communication together with other radio access network nodes without involving the core network.

Mobile110may be configured to initiate a request for D2D communication, which may explicitly or implicitly indicate that backup cellular capability is not needed. For example, mobile110may transmit a request for D2D communication using radio resource control, RRC, signaling, which is terminated at base station130. Base station130may be configured to process the request for D2D communication without involving the core network responsive to determining that the request for D2D communication was transmitted to base station130using RRC signaling. In some embodiments, base station130is configured to process all requests for D2D signaling without involving the core network, in some embodiments, mobile110is configured to determine a type of D2D communication that is being requested, and responsive to determining that the D2D communication requested is of local scope, mobile110may be configured to include in the request for D2D communication an indication that the D2D communication requested doesn't need backup cellular capability. The indication may take the form of a preconfigured bit or bits that are set to a certain value to indicate that backup cellular capability isn't needed for the D2D communication requested in the request. Alternatively, sending the request for D2D communication using RRC signaling may be an indication that backup cellular capability isn't needed.

Where backup cellular capability isn't needed, establishing the D2D communication without involving the core network provides a benefit by eliminating signaling involving the core network. Where acceptance of the core network isn't requested, delay in setting up the D2D communication may also be reduced since base station130needn't wait for permission from the core network before proceeding to allocate radio resources to the D2D communication.

In general, there is provided, a first apparatus, such as for example mobile110or a similar device or a control device for inclusion in mobile110to control the functioning thereof. The first apparatus comprises at least one processing core configured to determine that an opportunity for D2D communication exists. Determining that an opportunity for D2D communication exists may comprise determining that such an opportunity exists for the first apparatus. An opportunity may comprise that it is possible or probable that a D2D communication could be established. Where the device comprises a control device such as a processor, application-specific integrated circuit or similar, the at least one processing core may be comprised in the control device. The first apparatus further comprises at least one transmitter configured to cause a D2D communication request to be transmitted, wherein the D2D communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of D2D communication that is requested. In other words, the D2D communication request comprises a radio resource control signaling message and/or indication of a type of device-to-device communication that is requested. Where the first apparatus comprises mobile110, for example, the causing to be transmitted may occur in a radio transceiver comprised in mobile110, and the transmitter may comprise the radio transceiver. Where the first apparatus comprises a control device, the causing to be transmitted may occur in an input/output device comprised in the control device, such as for example a serial or parallel input/output port and associated pin or pins, in this case, the transmitter may comprise the serial or parallel input/output port and associated pin or pins. The input/output device may signal, using the pin or pins, internally in mobile110, for example, to a radio transceiver comprised in mobile110to cause the radio transceiver to transmit a the request. The signaling internally in mobile110may take place via electrical leads connecting the pin or pins of the input/output device to the radio transceiver.

The indication of a type of a D2D communication may indicate a type of a D2D communication selected in the first apparatus from a list comprising at least two types of D2D communication. In other words, the first apparatus may be configured to select a type of D2D communication from a list comprising at least two types of D2D communication, and include in the request an indication of the selected type.

In some embodiments, the indicated type of D2D communication comprises D2D communication without backup cellular capability. In some embodiments, the indicated type of D2D communication comprises D2D communication with backup cellular capability. In some embodiments, the indicated type of D2D communication comprises D2D communication with limited cellular capability. Backup cellular capability may comprise a capability to fallback to a cellular connection, via at least one base station, in case the D2D communication fails. D2D communication with limited cellular capability may comprise D2D communication that is authorized in the core network, but which doesn't have fallback capability. An advantage of such a type of communication may be that only limited core network involvement is needed in connection with establishing it, for example, core network node150may be capable of handling the core network part of the establishing without involving further core network nodes.

In some embodiments, the determining that an opportunity for D2D communication exists comprises at least one of receiving a device-to-device beacon and receiving information from a network element. The beacon may be broadcasted from at least one of a user equipment or a base station. The beacon may comprise information indicating that a D2D communication opportunity exists. The information received from a network element may comprise information indicating that a D2D communication opportunity exists in the location where the first apparatus presently finds itself. The network element may comprise a device-to-device registration server function, DRSF. In some embodiments, the beacon or information received from a network element comprises information concerning which type of D2D communication is available.

In some embodiments, the first apparatus is configured to transmit or cause to be transmitted, the request for D2D communication using a cellular communication technology. The request may be transmitted via wireless link111for example. The cellular communication technology may comprise, for example, GSM, WCDMA, LTE or another cellular technology. In some embodiments, the first apparatus is configured to participate in D2D communication with another device using a cellular technology. In other embodiments the first apparatus is configured to participate in D2D communication with another device using a non-cellular technology, such as for example Bluetooth or wireless local area network, WLAN. The D2D communication may use radio resources allocated to a cellular network, or alternatively radio resources not allocated to a cellular network, such as license-exempt radio resources or other frequency radio resource such as authorized shared access band. Participating in D2D communication with another mobile using a certain technology may comprise that a wireless link between the mobiles performs in accordance with the certain technology.

In some embodiments the D2D communication request comprises an estimate of link quality between two devices, such as for example a pathloss estimate. Another example of a link quality estimate is a block error rate determined from receiving broadcasted messages from another device.

In general there is provided a second apparatus such as for example a base station, such as base station130, or a control device for inclusion in a base station, to control the functioning thereof. The control device may comprise an integrated chip or chipset, for example. The second apparatus is configured with computer instructions stored in a memory, which are configured to cause the second apparatus to at least receive a D2D communication request from a first user equipment, and process the D2D communication request locally without involving a core network, wherein the D2D communication request at least one of comprises a RRC signaling message and comprises an indication of a type of D2D communication that is requested. The receiving may take place using a cellular communication technology, for example. The second apparatus may be configured to process the request locally responsive to the request comprising a RRC message or the indication. The second apparatus may be configured, in the absence of the indication in the request, to process the request at least in part by signaling to a core network element. In some embodiments, the second apparatus is configured to process the request at least in part by signaling to a core network element responsive to the request not comprising a RRC signaling message.

In some embodiments, processing the D2D communication request locally comprises querying a second user equipment for acceptance of the D2D communication, and in case the second user equipment indicates acceptance, allocating radio resources for the D2D communication. This achieves the advantage that radio resources are only allocated in case both user equipments indicate a willingness to participate in the D2D communication, and avoids the case where radio resources are allocated to a D2D communication that will have to be de-allocated if the second user equipment refuses to participate in the D2D communication.

FIG. 3illustrates a second system capable of supporting at least some embodiments of the invention.FIG. 3resemblesFIG. 1with like reference numbers relating to like units. InFIG. 3, mobile120is in a cell coverage area149of a cell controlled by base station140. Wireless link115partly traverses cell coverage area139and cell coverage area149. In the embodiment ofFIG. 3, base station130may be configured to process a D2D communication request from mobile110locally in the radio access network, without involving core network node150, by communicating with base station140via connection135. For example, to query mobile120for acceptance of a D2D communication, base station130may be configured to ask over connection135base station140to query mobile120, and to receive over connection135an indication of the response received from mobile120. The allocating of radio resources to the D2D communication may occur in co-operation between base station130and base station140, in that base station130allocates radio resources in cell coverage area139and base station140allocates radio resources in cell coverage area149. When the D2D communication is terminated, for example by mobile120, mobile120may be configured to transmit an indication of the termination to base station140via wireless link121, responsive to which base station140may be configured to indicate the termination to base station130via connection135. Base station140de-allocates the radio resources allocated to the D2D connection in cell coverage area149, and base station130does likewise, for the radio resources allocated to the D2D connection in cell coverage area139.

FIG. 4illustrates signaling according to at least one embodiment of the invention. The vertical axes correspond to mobile110, mobile120and base station130, respectively. At the beginning of the procedure, mobiles110and120are in a connected state. In phase410, mobile110determines an opportunity for a D2D communication with mobile120, for example by receiving a beacon transmission from mobile120or base station130, or an indication from base station130. Such an indication may be conveyed in a signaling message addressed to mobile110, for example. In phase420, at least in part responsive to phase410, mobile110transmits a D2D communication request to base station130. The request may comprise at least one of an identity of mobile110, an identity of mobile120, a link quality estimate determined between mobile110and mobile120using the beacon transmission, and a service mobile110is interested in obtaining from mobile120via the D2D communication. In phase430, base station130queries mobile120to find out, if mobile120is interested in participating in a D2D communication with mobile110. The query message of phase430may comprise at least one of an identity of mobile110and a service mobile110is interested in obtaining from or offering to mobile120via the D2D communication. Responsive to receiving the query message of phase430, mobile120decides on whether it wants to participate in a D2D communication with mobile110and in phase440, mobile120indicates whether it wants to participate in a D2D communication with mobile110by transmitting a signaling message to base station130. Phases430and440are optional as in some embodiments base station130is not configured to query mobile120before proceeding to radio resource allocation.

In phase450, if mobile120replied in the affirmative in phase440, base station130is configured to decide on radio resources to be allocated to the D2D communication between mobile110and mobile120. In phases460and470, base station130indicates the allocated radio resources to mobiles110and120, respectively. Responsive to being informed of radio resources allocated to the D2D communication, mobiles110and120initiate a D2D communication in phase480, for example by performing a contention free, random access procedure with each other. Optionally, in phases490and4100, mobiles110and120may inform base station130of successful startup of the D2D connection between the mobiles. In embodiments that support D2D communication involving mobiles under different base stations, the base stations may co-operate to cause the D2D communication to occur using, for example, a connection connecting the base stations with each other to enable them to exchange signaling messages without involving a core network. An example of such a connection is connection135ofFIG. 3. In such cases, each mobile would communicate with the base station it is attached to.

FIG. 5is a flowchart of a first method according to at least some embodiments of the invention. The method illustrated inFIG. 5may be performed in mobile110, for example. In phase510the existence of an opportunity for D2D communication is determined. The opportunity may involve at least one of certain device, a certain time and a certain location. In phase520, transmitting of a device-to-device communication request is caused, wherein the device-to-device communication request, at least one of comprises a radio resource control signaling message and comprises an indication of a type of device-to-device communication that is requested. The method may further comprise selecting a type of D2D communication from among a plurality of possible types of D2D communication.

FIG. 6is a flowchart of a second method according to at least some embodiments of the invention. The method illustrated inFIG. 5may be performed in base station130, for example. In phase610, a device-to-device communication request is received from a first user equipment. The receiving may take place using a cellular communication technology, for example. In phase620, the device-to-device communication request is processed locally without involving a core network, wherein the device-to-device communication request at least one of comprises a radio resource control signaling message and comprises an indication of a type of device-to-device communication that is requested.

FIG. 2illustrates a block diagram of an apparatus10such as, for example, a user equipment, in accordance with an example embodiment of the invention. While several features of the apparatus are illustrated and will be hereinafter described for purposes of example, other types of electronic devices, such as mobile telephones, mobile computers, portable digital assistants, PDAs, pagers, laptop computers, desktop computers, gaming devices, televisions, routers, home gateways, and other types of electronic systems, may employ various embodiments of the invention.

As shown, the mobile terminal10may include at least one antenna12in communication with a transmitter14and a receiver16. Alternatively transmit and receive antennas may be separate. The mobile terminal10may also include a processor20configured to provide signals to and receive signals from the transmitter and receiver, respectively, and to control the functioning of the apparatus. Processor20may be configured to control the functioning of the transmitter and receiver by effecting control signaling via electrical leads to the transmitter and receiver. Likewise processor20may be configured to control other elements of apparatus10by effecting control signaling via electrical leads connecting processor20to the other elements, such as for example a display or a memory. The processor20may, for example, be embodied as various means including circuitry, at least one processing core, one or more microprocessors with accompanying digital signal processor(s), one or more processor(s) without an accompanying digital signal processor, one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits such as, for example, an application specific integrated circuit, ASIC, or field programmable gate array, FPGA, or some combination thereof. Accordingly, although illustrated inFIG. 2as a single processor, in some embodiments the processor20comprises a plurality of processors or processing cores. Signals sent and received by the processor20may include signaling information in accordance with an air interface standard of an applicable cellular system, and/or any number of different wireline or wireless networking techniques, comprising but not limited to Wi-Fi wireless local access network, WLAN, techniques such as Institute of Electrical and Electronics Engineers, IEEE, 802.11, 802.16 and/or the like. In addition, these signals may include speech data, user generated data, user requested data, and/or the like. In this regard, the apparatus may be capable of operating with one or more air interface standards, communication protocols, modulation types, access types, and/or the like. More particularly, the apparatus may be capable of operating in accordance with various first generation, 1G, second generation, 2G, 2.5G, third-generation, 3G, communication protocols, fourth-generation, 4G, communication protocols, Internet Protocol Multimedia Subsystem, IMS, communication protocols, for example, session initiation protocol, SIP, and/or the like. For example, the apparatus may be capable of operating in accordance with 2G wireless communication protocols IS-136, Time Division Multiple Access TDMA, Global System for Mobile communications, GSM, IS-95, Code Division Multiple Access, CDMA, and/or the like. Also, for example, the mobile terminal may be capable of operating in accordance with 2.5G wireless communication protocols General Packet Radio Service, GPRS, Enhanced Data GSM Environment, EDGE, and/or the like. Further, for example, the apparatus may be capable of operating in accordance with 3G wireless communication protocols such as Universal Mobile Telecommunications System, UMTS, Code Division Multiple Access 2000, CDMA2000, Wideband Code Division Multiple Access, WCDMA, Time Division-Synchronous Code Division Multiple Access, TD-SCDMA, and/or the like. The apparatus may be additionally capable of operating in accordance with 3.9G wireless communication protocols such as Long Term Evolution, LTE, or Evolved Universal Terrestrial Radio Access Network E-UTRAN, and/or the like. Additionally, for example, the apparatus may be capable of operating in accordance with fourth-generation, 4G, wireless communication protocols such as LTE Advanced and/or the like as well as similar wireless communication protocols that may be developed in the future.

Some Narrow-band Advanced Mobile Phone System, NAMPS, as well as Total Access Communication System, TACS, mobile terminal apparatuses may also benefit from embodiments of this invention, as should dual or higher mode phone apparatuses, for example, digital/analog or TDMA/CDMA/analog phones. Additionally, apparatus10may be capable of operating according to Wi-Fi or Worldwide Interoperability for Microwave Access, WiMAX, protocols.

It is understood, that the processor20may comprise circuitry for implementing audio/video and logic functions of apparatus10. For example, the processor20may comprise a digital signal processor device, a microprocessor device, an analog-to-digital converter, a digital-to-analog converter, and/or the like. Control and signal processing functions of the mobile terminal may be allocated between these devices according to their respective capabilities. The processor may additionally comprise an internal voice coder, VC,20a, an internal data modem, DM20b, and/or the like. Further, the processor may comprise functionality to operate one or more software programs, which may be stored in memory. In general, processor20and stored software instructions may be configured to cause apparatus10to perform actions. For example, processor20may be capable of operating a connectivity program, such as a web browser. The connectivity program may allow the mobile terminal10to transmit and receive web content, such as location-based content, according to a protocol, such as wireless application protocol, WAP, hypertext transfer protocol, HTTP, and/or the like.

Apparatus10may also comprise a user interface including, for example, an earphone or speaker24, a ringer22, a microphone26, a display28, a user input interface, and/or the like, which may be operationally coupled to the processor20. In this regard, the processor20may comprise user interface circuitry configured to control at least some functions of one or more elements of the user interface, such as, for example, the speaker24, the ringer22, the microphone26, the display28, and/or the like. The processor20and/or user interface circuitry comprising the processor20may be configured to control one or more functions of one or more elements of the user interface through computer program instructions, for example, software and/or firmware, stored on a memory accessible to the processor20, for example, volatile memory40, non-volatile memory42, and/or the like. Although not shown, the apparatus may comprise a battery for powering various circuits related to the mobile terminal, for example, a circuit to provide mechanical vibration as a detectable output. The user input interface may comprise devices allowing the apparatus to receive data, such as a keypad30, a touch display, which is not shown, a joystick, which is not shown, and/or at least one other input device, in embodiments including a keypad, the keypad may comprise numeric 0-9 and related keys, and/or other keys for operating the apparatus.

As shown inFIG. 2, apparatus10may also include one or more means for sharing and/or obtaining data. For example, the apparatus may comprise a short-range radio frequency, RF, transceiver and/or interrogator64so data may be shared with and/or obtained from electronic devices in accordance with RF techniques. The apparatus may comprise other short-range transceivers, such as, for example, an infrared, IR, transceiver66, a Bluetooth™ BT, transceiver68operating using Bluetooth™ brand wireless technology developed by the Bluetooth™ Special Interest Group, a wireless universal serial bus, USB, transceiver70and/or the like. The Bluetooth™ transceiver68may be capable of operating according to low power or ultra-low power Bluetooth™ technology, for example, Wibree™, radio standards. In this regard, the apparatus10and in particular, the short-range transceiver may be capable of data to and/or receiving data from electronic devices within a proximity of the apparatus, such as within 10 meters, for example. Although not shown, the apparatus may be capable of transmitting and/or receiving data from electronic devices according to various wireless networking techniques, including 6LoWpan, Wi-Fi, low power, WLAN techniques such as IEEE 802.11 techniques, IEEE 802.15 techniques, IEEE 802.16 techniques, and/or the like.

The apparatus10may comprise memory, such as a subscriber identity module, SIM,38, a removable user identity module, R-UIM, and or the like, which may store information elements related to a mobile subscriber. In addition to the SIM, the apparatus may comprise other removable and/or fixed memory. The apparatus10may include volatile memory40an non-volatile memory42. For example, volatile memory40may include Random Access Memory, RAM, including dynamic and/or static RAM, on-chip or off-chip cache memory, and/or the like. Non-volatile memory42, which may be embedded and/or removable, may include, for example, read-only memory, flash memory, magnetic storage devices, for example, hard disks, floppy disk drives, magnetic tape, etc., optical disc drives and/or media, non-volatile random access memory, NVRAM, and/or the like. Like volatile memory40, non-volatile memory42may include a cache area for temporary storage of data. At least part of the volatile and/or non-volatile memory may be embedded in processor20. The memories may store one or more software programs, instructions, pieces of information, data, and/or the like which may be used by the apparatus for performing functions of the mobile terminal. For example, the memories may comprise an identifier, such as an international mobile equipment identification, IMEI, code, capable of uniquely identifying apparatus10.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is that unnecessary signaling in and/or to a core network may be eliminated. Another technical effect of one or more of the example embodiments disclosed herein is that delays in setting up D2D connections can be reduced.

It is also noted herein that while the above describes example embodiments the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.