GB2499411A

GB2499411A - Methods, apparatus and computer programs for network assisted D2D discovery

Info

Publication number: GB2499411A
Application number: GB1202574.8A
Authority: GB
Inventors: Timo Koskela; Jussi K Ojala; Jari Isokangas; Samuli Turtinen; Sami-Jukka Hakola
Original assignee: Renesas Mobile Corp
Current assignee: Renesas Electronics Corp
Priority date: 2012-02-15
Filing date: 2012-02-15
Publication date: 2013-08-21
Also published as: GB201202574D0

Abstract

Methods, apparatus and computer programs for network assisted D2D discovery are disclosed. At a network entity, device-to-device discovery related information is embedded into specific subframes of a multimedia broadcast/multicast service single frequency network transmission (S51). The network entity transmits the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication (S52). In embodiments, D2D discovery related information may be ststored at a network entity and forwarded to user equipment; User equipment may transmit D2D discovery related information to a network; the network may then transmit the information to user equipment within its area.

Description

1

METHODS, APPARATUS AND COMPUTER PROGRAMS FOR NETWORK ASSISTED D2D DISCOVERY

Technical Field

The present invention relates to network assisted device-to-device (D2D) discovery. More particularly, the present invention relates to methods, apparatus and computer programs for network assisted D2D discovery.

Background

The following abbreviations which may be found in the specification and/or the drawing figures are defined as follows:

BCCH broadcast channel

CN core network

D2D device-to-device

D2D IS D2D Information Server

DCI downlink control information

E-UTRAN Evolved UTRAN

LCID local ID

LTE Long Term Evo lution

M2M machine-to-machine

MAC medium access control

MBMS Multimedia Broadcast Multicast Service

MBSFN Multimedia Broadcast multicast service

Single Frequency Network

MCCH Multicast Control Channel

MCE Multi-cell/multicast Coordination Entity

MCH Multicast Channel

MCS Modulation and Coding Scheme

MME Mobility Management Entity

M-RNTI MBMS Radio Network Temporary Identifier

2

MSI

MCH Scheduling Information

MSP

MCH Scheduling Period

MTC

machine-type communication

MTCH

multicast traffic channel

PDCCH

physical downlink control channel

RAN

radio access network

RLC

radio link control

RLC-UM

RLC-Unacknowledged Mode

RRC

radio resource control

O&M

Organisation and Management

PDU

protocol data unit

RNTI

radio network temporary identifier

UE

user equipment

UTRAN

Universal Terrestrial Radio Access Network

15

Currently, there has been proposed a study item for the D2D in 3GPP TSG-RAN #52 plenary, 31 May-3 June 2011, as described in documents [1], [2] and [3] referenced below. One of the main targets is to evolve the LTE (Long Term Evolution) platform in order to intercept the demand of proximity-based applications 20 by studying enhancements to the LTE radio layers that allow devices to discover each other directly over the air, and potentially communicate directly, when this makes sense from a system management point of view, upon appropriate network supervision (cf. document [1]).

25 As described in document [1], the radio-based discovery process needs also to be coupled with a system architecture and a security architecture that allow the 3GPP operators to retain control of the device behaviour, for example who can emit discovery signals, when and where, what information the discovery signals carry, and what devices should do once they discover each other.

30

3

Currently SA WG1 is discussing and defining use cases and service requirements for the D2D. So far the following use cases have been proposed:

As examples of a possible use case are social applications, like e.g. the 5 exchange of files, photos, text messages, etc, VoIP conversation, one-way streaming video, and two-way video conferences.

Further examples of use cases are local advertising and multiplayer gaming. In multiplayer gaming, high resolution media (voice & video) can be exchanged 10 interactively either with all participants or certain team members within a game environment. The control inputs are expected to be received by all game participants with an ability to maintain causality.

As a further use case for D2D, network offloading is considered. In this 15 regard, when an opportunistic proximity offload potential exists, device 1 initiates a transfer of the media flow from the macro network to a proximity communications session with device 2. In such a case, it is possible to conserve macro network resources while maintaining the quality of user experience for the media session.

20 Moreover, D2D is also feasible for use with smart meters, e.g. with respect to communication among low capability MTC devices, or vehicular communication (safety and non-safety). In the long term, also a general M2M communication among devices/machines of different capability might be envisioned.

25 Furthermore, another use case of D2D is in the field of public safety, e.g.

TETRA (Terrestrial Trunked Radio) like functionality in both network controlled D2D and pure ad hoc D2D without network infrastructure.

In this regard, two types of D2D communication have been considered. One is 30 the network controlled D2D taking place under coverage of the controlling network

4

and the other is the ad hoc D2D communication taking place without any cellular system coverage supporting the D2D.

An example of an EUTRA (Evolved Universal Terrestrial Radio Access) 5 network architecture is schematically shown in Fig. 1.

As shown in Fig. 1, a MME (mobility management entity) communicates with several eNBs via an SI interface and eNBs can communicate between neighbouring eNBs via an X2 interface. EUTRAN specifies also an MBMS (Multimedia Broadcast 10 Multicast Service) function and an MBMS service area and MBSFN (Multimedia Broadcast multicast service Single Frequency Network) areas as illustrated schematically in Fig. 2 (cf. document [4]).

As defined in document [4], an MBSFN Area consists of a group of cells 15 within an MBSFN Synchronisation Area of a network, which are coordinated to achieve an MBSFN Transmission. Except for the MBSFN Area Reserved Cells, all cells within an MBSFN Area contribute to the MBSFN Transmission and advertise its availability. The UE may only need to consider a subset of the MBSFN areas that are configured, i.e. when it knows which MBSFN area applies for the service(s) it is 20 interested to receive.

An area considered in exemplary embodiments of the present invention is similar to a MBSFN area.

25 Multi-cell transmission of MBMS has the following characters (without being limited thereto), as defined in document [4]:

Synchronous transmission of MBMS within its MBSFN Area; Combining of MBMS transmission from multiple cells is supported; Scheduling of each MCH (Multicast Channel) is done by the MCE 30 (Multi-cell/multicast Coordination Entity);

5

MTCH (Multicast Traffic Channel) and MCCH (Multicast Control Channel) can be multiplexed on the same MCH and are mapped on MCH for p-t-m transmission;

MTCH and MCCH use the RLC-UM mode; 5 - The MAC subheader indicates the LCID for MTCH and MCCH;

The MBSFN Synchronisation Area, the MBSFN Area, and the MBSFN cells are semi-statically configured e.g. by O&M, MBSFN areas are static, unless changed by O&M (i.e. no dynamic change of areas).

10

MCH scheduling information (MSI) is provided per MCH to indicate which subframes are used by each MTCH during the MSP (MCH Scheduling Period). The following principles are used for the MSI:

it is used both when services are multiplexed onto the MCH and when 15 only a single service is transmitted on the MCH;

it is generated by the eNB and provided once at the beginning of the MSP;

it has higher scheduling priority than the MCCH and, when needed, it appears first in the PDU (Protocol Data Unit); 20 - it allows the receiver to determine what subframes are used by every

MTCH, sessions are scheduled in the order in which they are included in the MCCH session list;

it is carried in a MAC (Medium Access Control) control element which cannot be segmented;

25 - it carries the mapping of MTCHs to the subframes of the associated

MSP. This mapping is based on the indexing of subframes belonging to one MSP.

30

The following principles govern the MCCH structure:

One MBSFN Area is associated with one MCCH and one MCCH corresponds to one MBSFN Area;

6

The MCCH is sent on MCH;

MCCH consists of a single MBSFN Area configuration RRC (Radio Resource Control) message which lists all the MBMS services with ongoing sessions and an optional MBMS counting request message; 5 - MCCH is transmitted by all cells within an MBSFN Area, except the

MBSFN Area Reserved Cells;

MCCH is transmitted by RRC every MCCH repetition period;

MCCH uses a modification period;

A notification mechanism is used to announce changes of MCCH due 10 to either Session Start or the presence of an MBMS counting request message;

The notification is sent periodically throughout the modification period preceding the change of MCCH, in MBSFN subframes configured for notification;

15 - The DCI (Downlink Control Information) format 1C with M-RNTI

(MBMS Radio Network Temporary Identifier) is used for notification and includes an 8-bit bitmap to indicate the one or more MBSFN Area(s) in which the MCCH change(s);

The UE monitors more than one notification subframe per modification 20 period;

When the UE receives a notification, it acquires the MCCH at the next modification period boundary;

The UE detects changes to MCCH which are not announced by the notification mechanism by MCCH monitoring at the modification 25 period.

BCCH only points to the resources where the MCCH(s) can be found, i.e. it does not indicate the availability of the services.

- For each MCCH, BCCH indicates independently: 30 - the scheduling of the MCCH for multi-cell transmission on MCH;

7

the MCCH modification period, repetition period radio frame offset and subframe allocation;

an MCS which applies to the subframes indicated for MCCH scheduling and for the first subframe of all MSPs in that MBSFN Area.

5 - For the notification commonly used for all MCCH, BCCH:

configures the position of the MCCH change notification subframe and the number of occasions monitored by the UE;

indicates the mapping between the PDCCH bit(s) carried in the notification and the MCCH(s).

10

The MBMS BCCH information is embedded in SIB (System Information Block) 2 and SIB 13. Each UE in the network will read SIB 2. From there, the UE can find MBSFN-SubframeConfigList which consists of MBSFN-SubframeConfig elements that tell the sub-frames where MBMS information can be found (cf.

15 document [5]).

An example of a MBSFN architecture, as described in document [6] for example, is illustrated schematically in Fig. 3.

20 MBSFN architecture consists of several network elements depicted in Fig. 3.

At the core network side, a BM-SC (Broadcast Multicast Service Center) provides authentication and authorisation of content providers, and a MBMS GW (gateway) serves the multicast packet from BM-SC to eNBs via an Ml interface (user plane interface). A MME (Mobility Management Entity) provides the control plane

25 interface for the MBMS GW to the MCE (Multiccl^multicast Coordination Entity).

A MCE located at RAN (Radio Access Network) side is responsible for controlling time-frequency resources, and transmission parameters across the cell in the MBSFN Area.

30

8

Fig. 4 shows an example illustration of different MBSFN Areas, as defined in document [6], As shown in Fig. 4, one MBSFN area may consist of several cells and one cell can be a part of multiple MBSFN Areas. Thus, the MBSFN Areas may overlap.

5

Device and service discovery is considered to happen over the air, i.e. directly between the devices on given radio resources. However, there are certain challenges, like overhead from discovery signal transmissions related to eventual D2D communication resulted from the discovery. That is, there may be huge amount of 10 discovery signal transmissions by devices in a dense environment but only a small fraction will lead to actual pairing and D2D communication.

According to certain aspects of the present invention, there is considered a network side approach for the device and service discovery.

15

References:

[1] RP-110706, "On the need for a 3GPP study on LTE device-to-device discovery and communication", Qualcomm Incorporated, 3GPP TSG-RAN #52 plenary, May 31,

20 2011-June 3, 2011.

[2] Tdoc-RP-110707, "Study on LTE Device to Device Discovery and Communication -Radio Aspect^', Qualcomm Incorporated, 3GPP TSG-RAN #52 plenary, May 31, 2011-June3,2011.

25

[3] Tdoc-RP-110708, "Study on LTE Device to Device Discovery and Communication ^Service and System Aspect^', Qualcomm Incorporated, 3GPP TSG-RAN #52 plenary, May 31, 2011-June 3, 2011.

30 [4] 3GPP TS 36.300 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access

9

(E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 11), VI 1.0.0, December 2011.

[5] 3GPP TS 36.331 3rd Generation Partnership Project; Technical Specification 5 Group Radio Access Network; Evolved Universal Terrestrial Radio Access

(E-UTRA); Radio Resource Control (RRC); Protocol specification (Release 10); VI0.4.0, December 2011.

[6] E. Dahlman, S. Parkvall and J. Skold, "4G: LTE/LTE-Advanced for Mobile 10 Broadband", 2011.

Summary

According to various aspects of exemplary embodiments of the present 15 invention, there is proposed a network side approach for the device and service discovery.

According to exemplary aspects of the present invention, there are provided methods, apparatus and a computer program product for network assisted D2D 20 discovery.

According to a first aspect of the present invention, there is provided a method comprising:

embedding, at a network entity, device-to-device discovery related 25 information into specific subframes of a multimedia broadcast/multicast service single frequency network transmission, and transmitting, by the network entity, the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

30

10

According to a second aspect of the present invention, there is provided a method comprising:

receiving, at a network entity, device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device 5 discovery area,

storing the device-to-device discovery related information, and transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the device-to-device discovery area.

10

According to a third aspect of the present invention, there is provided a method comprising:

transmitting, by a user equipment capable of device-to-device communication located in a device-to-device discovery area, device-to-device discovery related

15 information of the user equipment to a network entity, and receiving at the user equipment, from the network entity, device-to-device discovery related information of other user equipment capable of device-to-device communication.

20 According to a fourth aspect of the present invention, there is provided apparatus for use in a network entity, the apparatus comprising:

a processing system constructed and arranged to cause the apparatus at least to perform:

embedding device-to-device discovery related information into specific

25 subframes of a multimedia broadcast/multicast service single frequency network transmission, and transmitting the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

30 According to a fifth aspect of the present invention, there is provided apparatus for use in a network entity, the apparatus comprising:

11

receiving device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device discovery area, 5 storing the device-to-device discovery related information, and transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the device-to-device discovery area.

10 According to a sixth aspect of the present invention, there is provided apparatus for use in a user equipment, the user equipment being capable of device-to-device communication located in a device-to-device discovery area, the apparatus comprising:

a processing system constructed and arranged to cause the apparatus at least to

15 perform:

transmitting device-to-device discovery related information of the user equipment to a network entity, and receiving from the network entity device-to-device discovery related information of other user equipment capable of device-to-device communication.

20

According to a seventh aspect of the present invention, there is provided apparatus comprising:

means for embedding device-to-device discovery related information into specific subframes of a multimedia broadcast/multicast service single frequency

25 network transmission, and means for transmitting the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

30 According to an eighth aspect of the present invention, there is provided apparatus comprising:

12

means for receiving device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device discovery area,

means for storing the device-to-device discovery related information, and 5 means for transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the device-to-device discovery area.

According to a ninth aspect of the present invention, there is provided 10 apparatus comprising:

means for transmitting, by a user equipment capable of device-to-device communication located in a device-to-device discovery area, device-to-device discovery related information of the user equipment to a network entity, and means for receiving, at the user equipment, device-to-device discovery related 15 information of other user equipment capable of device-to-device communication from the network entity.

There is also provided a computer program comprising computer-executable computer program code which, when the program is run on a computer (e.g. a 20 computer of an apparatus according to any one of the aforementioned apparatus-related exemplary aspects of the present invention), is arranged to cause the computer to carry out any of the methods described above.

The computer programs described above may comprise or be embodied as a 25 (tangible) computer-readable (storage) medium or the like on which the computer-executable computer program code is stored, and/or the program may be directly loadable into an internal memory of the computer or a processor thereof.

The processing systems described above may comprise at least one processor, 30 and at least one memory including computer program code, the at least one memory

13

and the computer program code arranged to, with the at least one processor, cause the apparatus at least to perform as described above.

Advantageous further developments or modifications of the aforementioned 5 exemplary aspects of the present invention are set out in the dependent claims.

According to exemplary aspects of the present invention as described above, already implemented LTE features can be used to support network based D2D discovery. Further, D2D devices do not need to transmit discovery probes/beacons in 10 order to find D2D capable users. Devices can obtain the available D2D ID list via reception of MBSFN transmission.

Brief Description of the Drawings

For a more complete understanding of exemplary embodiments of the present 15 invention, reference is now made to the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a diagram showing a schematic overview of an overall EUTRAN network architecture, to which the present invention is applicable;

20

Fig. 2 is a diagram showing a schematic overview of an MBMS service area;

Fig. 3 is a diagram schematically showing a MBMS architecture;

25 Fig. 4 is a diagram schematically showing an example of different MBSFN

areas;

30

Fig. 5 shows a schematic flowchart of an example for a method according to certain embodiments of the present invention;

14

Fig. 6 shows schematically a configuration of an example for a network entity according to certain embodiments of the present invention;

Fig. 7 shows a schematic flowchart of another example for a method according 5 to certain embodiments of the present invention;

Fig. 8 shows schematically a configuration of an example for another network entity according to certain embodiments of the present invention;

10 Fig. 9 shows a schematic flowchart of another example for a method according to certain embodiments of the present invention; and

Fig. 10 shows schematically a configuration of an example for a user equipment according to certain embodiments of the present invention.

15

Detailed Description

Exemplary aspects of the present invention will be described herein below. More specifically, exemplary aspects of the present are described hereinafter with reference to particular non-limiting examples and to what are presently considered to 20 be conceivable embodiments of the present invention. A person skilled in the art will appreciate that the invention is by no means limited to these examples, and may be more broadly applied.

It is to be noted that the following description of the present invention and its 25 embodiments mainly refers to specifications being used as non-limiting examples for certain exemplary network configurations and deployments. Namely, the present invention and its embodiments are mainly described in relation to 3GPP specifications used as non-limiting examples for certain exemplary network configurations and deployments. In particular, a LTE/LTE-Advanced communication system is used as a 30 non-limiting example for the applicability of thus described exemplary embodiments. As such, the description of exemplary embodiments given herein specifically refers to

15

terminology which is directly related thereto. Such terminology is only used in the context of the presented non-limiting examples, and naturally does not limit the invention in any way. Rather, any other network configuration or system deployment, etc. may also be utilised as long as compliant with the features described herein.

5

Hereinafter, various embodiments and implementations of the present invention and its aspects or embodiments are described using several alternatives. It is generally noted that, according to certain needs and constraints, all of the described alternatives may be provided alone or in any conceivable combination (also including

10 combinations of individual features of the various alternatives).

According to exemplary embodiments of the present invention, in general terms, there are provided mechanisms, measures and means for network assisted D2D discovery.

15

According to an exemplary embodiment of the present invention, the MBSFN system described above is used for distributing D2D discovery related information. In such a case, specific MBSFN subframes are configured to convey D2D discovery related information.

20

In another exemplary embodiment, the MBSFN areas are arranged to be'D2D Discovery Information Area^'. Such D2D Discovery Areas may consist of multiple MBSFN Areas.

25 In another exemplary embodiment, a new CN/RAN logical element 'D2D

Information Server (D2D IS)" is introduced to the network which gathers and maintains D2D Discovery related information.

Such a server may be located inside the CN/RAN and has a user/control plane

30 interface to the MBMS GW. The devices provide their IDs and other relevant

16

information to the D2D Information Server, and then this information is distributed from the D2D IS via the user plane interface to the other devices.

The D2D IS also may use the MBSFN system described above for distributing 5 the D2D discovery related information, where specific MBSFN subframes are configured to convey D2D discovery related information.

In another exemplary embodiment, the D2D information is stored and maintained by the operator. In such a case, the D2D IS element is a user plane entity 10 and requires subscription. Alternatively, the D2D information is stored automatically upon detecting a D2D-capable device in the network. That is, the device may use a specific option to indicate whether it allows the information to be stored at the D2D IS or not.

15 According to another exemplary embodiment, the D2D discovery related information that are stored can be the D2D-capable devices (more particularly, the IDs of these devices) in the D2D discovery area. The D2D ID of the device can be, for example, a numerical value (like e.g. '3421454), a text value (like e.g. "John's Mobile Dcvicd', or the like).

20

Further, the stored information may be proximity applications, i.e. applications running on devices that are D2D-capable, like e.g. a media server or the like.

The information further may also be, for example, the M2M device IDs in the 25 D2D discovery area, or the neighbouring D2D Discovery Areas and cell IDs.

Note that all or only some of the above mentioned D2D discovery related information may be received and distributed through the network. The amount of information each device is allowed to store to the D2D IS may be limited by the 30 network.

17

In view of the above, according to certain embodiments of the present invention, it is possible to use already implemented LTE features to support network based D2D discovery. Hence, D2D devices do not need to transmit discovery probes/beacons in order to find D2D capable users. Devices can obtain the available 5 D2D ID list via reception of MBSFN transmission.

Fig. 5 shows a schematic flowchart of an example for a method according to certain embodiments of the present invention. That is, as shown in Fig. 1, this method comprises embedding, at a network entity, device-to-device discovery related 10 information into specific subframes of a multimedia broadcast/multicast service single frequency network transmission at a step S51, and transmitting, at a step S52 by the network entity, the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

15 Fig. 6 shows a schematic configuration of an example for a network entity according to certain embodiments of the present invention. One option for implementing this example for a network entity according to certain embodiments of the present invention would be a service centre such as a Broadcast Multicast Service Center of a MBMS architecture according to LTE. A further option for implementing 20 this example for a network entity according to certain embodiments of the present invention would be the above described D2D Information Server applicable to be used with a MBMS architecture according to LTE.

Specifically, as shown in Fig. 6, the example for a network entity 60 25 comprises at least one processor 61, at least one memory 62 including computer program code and an interface 63 which are connected by a bus 64 or the like. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus at least to perform embedding device-to-device discovery related information into specific subframes of a multimedia 30 broadcast/multicast service single frequency network transmission, and transmitting

18

the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

Fig. 7 shows a schematic flowchart of another example for a method according 5 to certain embodiments of the present invention. That is, as shown in Fig. 7, this method comprises receiving, at a network entity, device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device discovery area at a step S71, storing, at a step S72, the device-to-device discovery related information, and transmitting, at a step S73, the device-to-10 device discovery related information to user equipment capable of device-to-device communication in the device-to-device discovery area.

According to exemplary embodiments of the present invention, the method further comprises detecting the device-to-device capable user equipment in the 15 device-to-device discovery area, wherein the device-to-device discovery related information is received and stored upon detecting the device-to-device capable user equipment in the device-to-device discovery area.

According to exemplary embodiments of the present invention, the method 20 further comprises receiving an indication from the detected device-to-device capable user equipment, and determining based on the received indication whether to store device-to-device discovery related information of the detected device-to-device capable user equipment.

25 According to exemplary embodiments of the present invention, the network entity is located in a radio access network of a multimedia broadcast/multicast service single frequency network.

According to exemplary embodiments of the present invention, the network 30 entity is located in a core network of a multimedia broadcast/multicast service single frequency network.

19

According to exemplary embodiments of the present invention, the network entity provides a user plane interface and a control plane interface to a multimedia broadcast/multicast service gateway of a multimedia broadcast/multicast service 5 single frequency network.

According to exemplary embodiments of the present invention, the network entity is a user plane entity and requires subscription.

10 Fig. 8 shows a schematic configuration of another example for a network entity according to certain embodiments of the present invention. One option for implementing this example for a network entity according to certain embodiments of the present invention would be a device-to-device information server (D2D IS) applicable to be used with a MBMS architecture according to LTE.

15

Specifically, as shown in Fig. 8, the example for a network entity 80 comprises at least one processor 81, at least one memory 82 including computer program code and an interface 83 which are connected by a bus 84 or the like. The at least one memory and the computer program code are arranged to, with the at least 20 one processor, cause the apparatus at least to perform receiving device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device discovery area, storing the device-to-device discovery related information, and transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the 25 device-to-device discovery area.

For further functions of the network entity according to further exemplary embodiments of the present invention, reference is made to the above description of a method according to certain embodiments of the present invention, as described in 30 connection with Fig. 7.

20

Fig. 9 shows a schematic flowchart of another example for a method according to certain embodiments of the present invention. That is, as shown in Fig. 9, this method comprises transmitting, by a user equipment capable of device-to-device communication and located in a device-to-device discovery area, device-to-device 5 discovery related information of the user equipment to a network entity in a step S91, and receiving, at the user equipment, device-to-device discovery related information of other user equipment capable of device-to-device communication from the network entity in a step S92.

10 According to exemplary embodiments of the present invention, the method further comprises transmitting, by the user equipment, an indication indicating whether the device-to-device discovery related information of the device-to-device capable user equipment is allowed to be stored at the network entity.

15 Fig. 10 shows a schematic configuration of an example for a user equipment according to certain embodiments of the present invention. One option for implementing this example for a user equipment according to certain embodiments of the present invention would be a component in a handset such as user equipment UE according to LTE.

20

Specifically, as shown in Fig. 10, the example for a user equipment 100 comprises at least one processor 101, at least one memory 102 including computer program code and an interface 103 which are connected by a bus 104 or the like. The at least one memory and the computer program code are arranged to, with the at least

25 one processor, cause the user equipment capable of device-to-device communication located in a device-to-device discovery area at least to perform transmitting, device-to-device discovery related information of the user equipment to a network entity, and receiving device-to-device discovery related information of other user equipment capable of device-to-device communication from the network entity.

30

21

For further functions of the user equipment according to further exemplary embodiments of the present invention, reference is made to the above description of a method according to certain embodiments of the present invention, as described in connection with Fig. 9.

5

According to further exemplary embodiments of the present invention, as described above:

- the device-to-device discovery related information is an identification of an device-to-device capable user equipment in an device-to-device discovery area;

10 - the identification of the device-to-device capable user equipment is a numerical value or a text value;

- the device-to-device discovery related information is a proximity application running on the device-to-device capable user equipment;

- the device-to-device discovery related information is an identification of a 15 device capable of machine-to-machine communication;

- the device-to-device discovery related information are neighbouring device-to-device discovery areas and identifications of cells in the device-to-device discovery areas;

- the device-to-device discovery area is a multimedia broadcast/multicast 20 service single frequency network transmission area and the device-to-device discovery area comprises a plurality of multimedia broadcast/multicast service single frequency network transmission areas.

In the foregoing exemplary description of the apparatus, i.e. the user 25 equipment and the network entities, only the units that are relevant for understanding the principles of the invention have been described using functional blocks. The apparatus may comprise further units that are necessary for their respective operation as user equipment or network entity, respectively. However, a description of these units is omitted in this specification. The arrangement of the functional blocks of the 30 apparatus is not construed to limit the invention, and the functions may be performed by one block or further split into sub-blocks. Further, the apparatus, i.e. the user

22

equipment and the respective entity, may be connected via a link 65/85/105. The link 65/85/105 may be a physical and/or logical coupling, which is implementation-independent (e.g. wired or wireless).

5 According to exemplary embodiments of the present invention, a system may comprise any conceivable combination of the thus depicted devices/apparatus and other network elements, which are arranged to cooperate as described above.

In general, it is to be noted that respective functional blocks or elements 10 according to above-described aspects can be implemented by any known means, either in hardware and/or software, respectively, if it is only adapted to perform the described functions of the respective parts. The mentioned method steps can be realised in individual functional blocks or by individual devices, or one or more of the method steps can be realised in a single functional block or by a single device.

15

Generally, any procedural step or functionality is suitable to be implemented as software or by hardware without changing the idea of the present invention. Such software may be software code independent and can be specified using any known or future developed programming language, such as e.g. Java, C++, C, and Assembler, 20 as long as the functionality defined by the method steps is preserved. Such hardware may be hardware type independent and can be implemented using any known or future developed hardware technology or any hybrids of these, such as MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), TTL (Transistor-25 Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit)) components, FPGA (Field-programmable Gate Arrays) components, CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components. A device/apparatus may be represented by a semiconductor chip, a chipset, system in package (SIP), or a (hardware) module comprising such 30 chip or chipset; this, however, does not exclude the possibility that a functionality of a device/apparatus or module, instead of being hardware implemented, may be

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implemented as software in a (software) module such as a computer program or a computer program product comprising executable software code portions for execution/being run on a processor. A device may be regarded as a device/apparatus or as an assembly of more than one device/apparatus, whether functionally in 5 cooperation with each other or functionally independently of each other but in a same device housing, for example.

Apparatus and/or means or parts thereof can be implemented as individual devices, but this does not exclude that they may be implemented in a distributed 10 fashion throughout the system, as long as the functionality of the device is preserved. Such and similar principles are to be considered as known to a skilled person.

Software in the sense of the present description comprises software code as such comprising code means or portions or a computer program or a computer 15 program product for performing the respective functions, as well as software (or a computer program or a computer program product) embodied on a tangible medium such as a computer-readable (storage) medium having stored thereon a respective data structure or code means/portions or embodied in a signal or in a chip, potentially during processing thereof.

20

The present invention also covers any conceivable combination of method steps and operations described above, and any conceivable combination of nodes, apparatus, modules or elements described above, as long as the above-described concepts of methodology and structural arrangement are applicable.

25

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with 30 one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described

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above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

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Claims

1. A method comprising:

embedding, at a network entity, device-to-device discovery related 5 information into specific subframes of a multimedia broadcast/multicast service single frequency network transmission, and transmitting, by the network entity, the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

10

2. A method comprising:

receiving, at a network entity, device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device discovery area,

15 storing the device-to-device discovery related information, and transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the device-to-device discovery area.

20 3. A method according to claim 2, comprising:

detecting the device-to-device capable user equipment in the device-to-device discovery area,

wherein the device-to-device discovery related information is received and stored upon detecting the device-to-device capable user equipment in the device-to-25 device discovery area.

4. A method according to claim 3, comprising:

receiving an indication from the detected device-to-device capable user equipment, and

26

determining based on the received indication whether to store device-to-device discovery related information of the detected device-to-device capable user equipment.

5 5. A method according to any of claims 2 to 4, wherein the network entity is located in a radio access network of a multimedia broadcast/multicast service single frequency network.

6. A method according to any of claims 2 to 5, wherein the network entity is 10 located in a core network of a multimedia broadcast/multicast service single frequency network.

7. A method according to any of claims 2 to 6, wherein the network entity provides a user plane interface and a control plane interface to a multimedia

15 broadcast/multicast service gateway of a multimedia broadcast/multicast service single frequency network.

8. A method according to any of claims 2 to 7, wherein the network entity is a user plane entity and requires subscription.

20

9. A method according to any of claims 2 to 8, wherein the device-to-device discovery area is a multimedia broadcast/multicast service single frequency network transmission area and the device-to-device discovery area comprises a plurality of multimedia broadcast/multicast service single 25 frequency network transmission areas.

10. A metho d comprising:

transmitting, by a user equipment capable of device-to-device communication located in a device-to-device discovery area, device-to-device discovery related 30 information of the user equipment to a network entity, and

27

receiving at the user equipment, from the network entity, device-to-device discovery related information of other user equipment capable of device-to-device communication.

5 11. A method according to claim 10, comprising:

transmitting, by the user equipment, an indication indicating whether the device-to-device discovery related information of the device-to-device capable user equipment is allowed to be stored at the network entity.

10 12. A method according to any of claims 1 to 11, wherein the device-to-device discovery related information comprises an identification of a device-to-device capable user equipment in a device-to-device discovery area.

13. A method according to claim 12, wherein the identification of the device-to-15 device capable user equipment is a numerical value or a text value.

14. A method according to any of claims 1 to 13, wherein the device-to-device discovery related information comprises a proximity application running on the device-to-device capable user equipment.

20

15. A method according to any of claims 1 to 14, wherein the device-to-device discovery related information comprises an identification of a device capable of machine-to-machine communication.

25 16. A method according to any of claims 1 to 15, wherein the device-to-device discovery related information comprises neighbouring device-to-device discovery areas and identifications of cells in the device-to-device discovery areas.

17. Apparatus for use in a network entity, the apparatus comprising: 30 a processing system constructed and arranged to cause the apparatus at least to perform:

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embedding device-to-device discovery related information into specific subframes of a multimedia broadcast/multicast service single frequency network transmission, and transmitting the specific subframe containing device-to-device discovery 5 related information to user equipment capable of device-to-device communication.

18. Apparatus for use in a network entity, the apparatus comprising:

10 receiving device-to-device discovery related information of user equipment capable of device-to-device communication in a device-to-device discovery area, storing the device-to-device discovery related information, and transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the device-to-device 15 discovery area.

19. Apparatus according to claim 18, wherein the processing system is arranged to cause the apparatus at least to perform:

detecting the device-to-device capable user equipment in the device-to-device 20 discovery area,

wherein the device-to-device discovery related information is received and stored upon detecting the device-to-device capable user equipment in the device-to-device discovery area.

25 20. Apparatus according to claim 19, wherein the processing system is arranged to cause the apparatus at least to perform:

receiving an indication from the detected device-to-device capable user equipment, and determining based on the received indication whether to store device-to-device 30 discovery related information of the detected device-to-device capable user equipment.

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21. Apparatus according to any of claims 18 to 20, wherein the network entity is located in a radio access network of a multimedia broadcast/multicast service single frequency network.

5

22. Apparatus according to any of claims 18 to 21, wherein the network entity is located in a core network of a multimedia broadcast/multicast service single frequency network.

10 23. Apparatus according to any of claims 18 to 22, wherein the network entity provides a user plane interface and a control plane interface to a multimedia broadcast/multicast service gateway of a multimedia broadcast/multicast service single frequency network.

15 24. Apparatus according to any of claims 18 to 23, wherein the network entity is a user plane entity and requires subscription.

25. Apparatus according to any one of claims 18 to 24, wherein the device-to-device discovery area is a multimedia broadcast/multicast 20 service single frequency network transmission area and the device-to-device discovery area comprises a plurality of multimedia broadcast/multicast service single frequency network transmission areas.

26. Apparatus for use in a user equipment, the user equipment being capable of 25 device-to-device communication located in a device-to-device discovery area, the apparatus comprising:

transmitting device-to-device discovery related information of the user 30 equipment to a network entity, and

30

receiving from the network entity device-to-device discovery related information of other user equipment capable of device-to-device communication.

27. Apparatus according to claim 26, wherein the processing system is arranged to 5 cause the apparatus at least to perform transmitting an indication indicating whether the device-to-device discovery related information of the device-to-device capable user equipment is allowed to be stored at the network entity.

28. Apparatus according to any of claims 17 to 27, wherein the device-to-device 10 discovery related information comprises an identification of an device-to-device capable user equipment in an device-to-device discovery area.

29. Apparatus according to claim 28, wherein the identification of the device-to-device capable user equipment is a numerical value or a text value.

15

30. Apparatus according to any of claims 17 to 29, wherein the device-to-device discovery related information comprises a proximity application running on the device-to-device capable user equipment.

20 31. Apparatus according to any of claims 17 to 30, wherein the device-to-device discovery related information comprises an identification of a device capable of machine-to-machine communication.

32. Apparatus according to any of claims 17 to 31, wherein the device-to-device 25 discovery related information comprises neighbouring device-to-device discovery areas and identifications of cells in the device-to-device discovery areas.

33. Apparatus comprising:

means for embedding device-to-device discovery related information into 30 specific subframes of a multimedia broadcast/multicast service single frequency network transmission, and

31

means for transmitting the specific subframe containing device-to-device discovery related information to user equipment capable of device-to-device communication.

5 34. Apparatus comprising:

means for storing the device-to-device discovery related information, and 10 means for transmitting the device-to-device discovery related information to user equipment capable of device-to-device communication in the device-to-device discovery area.

35. Apparatus comprising:

15 means for transmitting, by a user equipment capable of device-to-device communication located in a device-to-device discovery area, device-to-device discovery related information of the user equipment to a network entity, and means for receiving, at the user equipment, device-to-device discovery related information of other user equipment capable of device-to-device communication from 20 the network entity.

36. A computer program comprising computer-executable computer program code which, when the program is run on a computer, is arranged to cause the computer to carry out the method according to any of claims 1 to 16.

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37. A computer program according to claim 36, embodied as a computer-readable storage medium.

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38. A method of network assisted D2D discovery, substantially in accordance with any of the examples as described herein with reference to and illustrated by the accompanying drawings.

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39. Apparatus for network assisted D2D discovery, substantially in accordance with any of the examples as described herein with reference to and illustrated by the accompanying drawings.