WO2013120267A1

WO2013120267A1 - Control of device-to-device communication

Info

Publication number: WO2013120267A1
Application number: PCT/CN2012/071252
Authority: WO
Inventors: Chunyan Gao; Pengfei Sun; Wei Hong; Wei Bai; Jing HAN; Haiming Wang
Original assignee: Renesas Mobile Corporation
Priority date: 2012-02-17
Filing date: 2012-02-17
Publication date: 2013-08-22

Abstract

It is provided a method, comprising getting an assignment of a first resource usable for device-to-device communication from a base station; determining a cell edge condition, which is only fulfilled if an apparatus performing the method is determined to be at an edge of a cell of the base station to which the apparatus is attached; detecting a request from another apparatus for setting up a device-to-device communication; if the cell edge condition is not fulfilled: determining to set up the device-to- device communication to the other apparatus using at least a first part of the first resource only; and if the cell edge condition is fulfilled : monitoring an assignment of a second resource for device-to-device communication of the other apparatus, and determining to set up the device-to-device communication to the other apparatus using at least one of a second part of the first resource and a part of the second resource.

Description

CONTROL OF DEVICE-TO-DEVICE COMMUNICATION

Field of the invention

The present invention relates to an apparatus, a method, and a computer program product for improving device-to-device communication. More particularly, the present invention relates to an apparatus, a method, and a computer program product for controlling device-to-device communication depending on the location of the device.

Background of the invention

Abbreviations

3GPP Third Generation Partnership Project

CA Carrier Aggregation

D2D Device to Device

DL Downlink

E-UTRA Evolved Universal Terrestrial Radio Access

eNB evolved NodeB

Id Identifier

LTE Long Term Evolution

LTE-A Long Term Evolution Advanced

OAM Operation and Maintanance

OTAC Over the Air Configuration

RAN Radio Access Network

RAT Radio Access Technology

Rel Release

RNC Radio Network Controller

RSRP Reference Signal Received Power

RSRQ Reference Signal Received Quality

Rx Reception

SA System Architecture

TA Timing Advance TD Timing Delay

TS Technical Specification

Tx Transmission

UE User Equipment

UMTS Universal Mobile Telecommunications System

WG Working Group

Device to Device (D2D) communication is currently a hot topic under discussion in telecommunication industry. Motivation for D2D is that it couid be used to improve the resource usage efficiency, reduce the power consumption at both eNB and UE side, offload the traffic from the cellular network, and also possibly enables some new service types in future cellular networks. A study item for the D2D was proposed in 3GPP TSG-RAN #52 plenary, 31 May - 3 June 2011 [1]. Discussion on use cases and requirements for the proximity communication is ongoing in 3GPP as a SA WG1 work item.

According to one proposed requirement for D2D (proximity communication) [2], "The Evolved Packet System shall provide the operator with the ability to specify radio parameters for Proximity Services that minimize the impact (interference, congestion) on the network". It means that the D2D operation should avoid causing obvious interference and signaling overhead to macro network. One way to realize minimized signaling overhead is to allow autonomous D2D operation, including device discovery and D2D data transmission. However, at the same time the interference issue has to be kept in mind, and according to [3], "The operator shall be able to define the conditions under which direct and macro modes of data communication are utilized". Hence, control by eNB is still needed to some level. References

[1] RP-110706, "On the need for a 3GPP study on LTE device-to-device discovery and communication", Qualcomm Incorporated [2] Sl-113010, "FS_ProSe: Public Safety Use Cases", Alcatel-Lucent, NIST, Nokia Siemens Networks, U.S Cellular, 3GPP TSG-SA WG1 Meeting #56

[3] Sl-113016, "Requirements associated with Proximity Network Offload Use Case", Qualcomm Incorporated, Lightsquared, ETRI, 3GPP TSG-SA WG1 Meeting #56

Summary of the invention

It is an object of the present invention to improve the prior art.

In particular, it is an object to provide an operation principle and the corresponding signaling to help interference control at eNB side for inter-cell D2D operation. According to a first aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and at least one interface configured for communication with at least a base station and another apparatus, the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform : getting an assignment of a first resource usable for device-to-device communication from the base station; determining a cell edge condition of the apparatus, which is only fulfilled if the apparatus is determined to be at an edge of a cell of the base station to which the apparatus is attached; detecting a request from the other apparatus for setting up a device-to-device communication; if the cell edge condition is not fulfilled : determining to set up the device-to-device communication to the other apparatus using at least a first part of the first resource only; and if the cell edge condition is fulfilled : monitoring an assignment of a second resource for device-to-device communication of the other apparatus, and determining to set up the device-to-device communication to the other apparatus using at least one of a second part of the first resource and a part of the second resource. According to a second aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and at least one interface configured for communication with at least a base station, and another apparatus, the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform : getting an assignment of a first resource usable for device-to-device communication from the base station; determining a cell edge condition of the apparatus, which is only fulfilled if the apparatus is determined to be at an edge of a cell of the base station to which the apparatus is attached; determining to send a discovery signal and/or to send a setup request to set up a device-to-device communication to the other apparatus, wherein at least one of the discovery signal and the setup request comprises an edge condition information about the cell edge condition.

The apparatuses of the first and second aspects may be used on a terminal side of a cellular system.

According to a third aspect of the invention, there is provided an apparatus, comprising at least one processor, at least one memory including computer program code, and at least one interface configured for communication with at least a user equipment and another apparatus, the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform : determining to broadcast an information about a first D2D resource scheduled for use for a device-to-device communication by the user equipment attached to the apparatus and an information about a second D2D resource and a corresponding cell identification received from the other apparatus. The apparatus of the third aspect may be used on a network side of a cellular system.

According to a fourth aspect of the invention, there is provided a method, comprising getting an assignment of a first resource usable for device-to- device communication from a base station; determining a cell edge condition, which is only fulfilled if an apparatus performing the method is determined to be at an edge of a cell of the base station to which the apparatus is attached; detecting a request from another apparatus for setting up a device-to-device communication; if the cell edge condition is not fulfilled : determining to set up the device-to-device communication to the other apparatus using at least a first part of the first resource only; and if the cell edge condition is fulfilled: monitoring an assignment of a second resource for device-to-device communication of the other apparatus, and determining to set up the device-to-device communication to the other apparatus using at least one of a second part of the first resource and a part of the second resource.

According to a fifth aspect of the invention, there is provided a method, comprising getting an assignment of a first resource usable for device-to- device communication from a base station; determining a cell edge condition of the apparatus, which is only fulfilled if an apparatus performing the method is determined to be at an edge of a cell of the base station to which the apparatus is attached; determining to send a discovery signal and/or to send a setup request to set up a device-to device communication to the other apparatus, wherein at least one of the discovery signal and the setup request comprises an edge condition information about the cell edge condition.

The methods according to the fourth and fifth aspects may be methods of D2D communication control on a terminal side of a cellular network.

According to a sixth aspect of the invention, there is provided a method, comprising determining to broadcast an information about a first D2D resource scheduled for use for a device-to-device communication by a user equipment attached to an apparatus performing the method and an information about a second D2D resource and a corresponding cell identification received from another apparatus. The method according to the sixth aspect may be a method of D2D communication control on a network side of a cellular network.

According to a seventh aspect of the invention, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method according to any one of the fourth to sixth aspects. The computer program product may be embodied on a computer-readable medium.

According to some embodiments of the invention, at least the following advantages are achieved:

• Inter-cell D2D operation is enabled without causing much interference to macro operation;

· Interference control is provided, avoiding at the same time unnecessary signaling;

• Device power is saved, e.g. by avoiding unnecessary discovery operation;

• eNB gets aware of device's connectivity capability (based on information of the resource used for its D2D operation)

^• eNB may adapt resource scheduling depending on the D2D operation, allowing for highly performing simultaneous operation of macro mode and D2D. It is to be understood that any of the above modifications can be applied singly or in combination to the respective aspects to which they refer, unless they are explicitly stated as excluding alternatives.

Brief description of the drawings

Further details, features, objects, and advantages are apparent from the following detailed description of the preferred embodiments of the present invention which is to be taken in conjunction with the appended drawings, wherein

Fig. 1 shows an example of D2D resource allocation in neighboring cells according to an embodiment of the invention;

Fig. 2 shows an example of user equipments and NodeBs according to embodiments of the invention; Fig. 3 shows an example of the inter-cell D2D operation according to an embodiment of the invention;

Fig. 4 show an apparatus according to an embodiment of the invention; Fig. 5 shows a method according to an embodiment of the invention; Fig. 6 shows an apparatus according to an embodiment of the invention; Fig. 7 shows a method according to an embodiment of the invention.

Detailed description of certain embodiments

Herein below, certain embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein the features of the embodiments can be freely combined with each other unless otherwise described. However, it is to be expressly understood that the description of certain embodiments is given for by way of example only, and that it is by no way intended to be understood as limiting the invention to the disclosed details.

Moreover, it is to be understood that the apparatus is configured to perform the corresponding method, although in some cases only the apparatus or only the method are described. Comparing with macro operation, the D2D communication has many advantages, e.g. saves resource compared with communication via network, interference reduction due to low transmit power, power saving at device side due to low transmit power. Such saving in resource and energy is more obvious for devices at the cell-edge, hence D2D is more desired in this case. However, for a cell-edge device, the target device to be paired may be served by a neighboring cell. Considering that each cell may have different traffic load and user distribution, the resource allocated for D2D communication may not be the same in the different cells.

An example is shown in Fig, 1, where cell#l, cell#2 and cell#3 are neighboring cells, and the 3 cells all operate in carrier #1, but different resources are reserved for D2D in the three cells and the reserved resources may or may not overlap. In the example shown in Fig. 1, device A in cell#l and device B in cell#2 are in proximity and the direct (D2D) communication between them can be beneficial for both devices and the system. But in case different resources for D2D are allocated in each cell, how to coordinate on the resource to be used for D2D communication?

For example, if using cell#l's D2D resource, there is the possibility that it causes interference to cell#2's macro operation (i.e. communication via the network), and if using cell#2's D2D resource, there may be an impact to cell#l .

Besides the interference issue, another impact can be seen from a 2^nd example, where cell#l and cell#2 operate in different bands, and in cell#l some resource in band#l is reserved for D2D, while in cell#2 some resource in band#2 is reserved for D2D. In such a case, if the cell-edge device A from cell#l and device B from cell#2 setup a D2D link in band#2's D2D resource, device A's connection capability to its own cell in band#l may be changed. For example, if device A is capable of inter-band carrier aggregation, then the D2D operation with device B and macro connection with cell#l may be simultaneous, while when D2D operation is performed in band#l, simultaneous operation may not be possible since Tx and Rx in the same band in the same device cause much self-interference. If such change of connectivity capability is known by eNB, it can help improving the scheduling efficiency.

From the above analysis, one may see that the inter-cell D2D operation may cause interference issues or a device connection capability change. It is desirable that this can be controlled by eNB to improve interference control and resource efficiency.

To reduce interference and to enable resource efficiency improvement, it is controlled under which condition the inter-cell D2D operation is allowed, and under which condition, the inter-cell D2D operation need to be known to an e Bs. The operation is based on the following assumptions:

- The eNB has knowledge of neighbor cell's D2D resource allocation via X2 interface or OTAC or OAM, or based on UE report, and this information may be broadcasted to devices attached to the eNB. For example, the broadcasted information may comprise cell-ID#l's D2D resource is SI, cell-ID#2's D2D resource is S2. Based on the cell-ID information included in a discovery signal from a device B, the device A which detected the discovery signal of device B may derive the configured D2D resource for device B. Furthermore, it enables device A to know whether device B is in the same cell or not.

- In discovery signal, there is cell Id information. In addition, it may comprise macro status (e.g, whether device is in cell edge, which means that it could use other cells' D2D resource). Alternatively or in addition, the macro status may be comprised in a request to set up D2D communication.

The following rule is defined for inter-cell D2D operation: The allowed D2D operation depends on whether the device is at the cell edge or not.

- In some embodiments, the decision whether or not the device is at the cell edge, depends on RSRP and/ or RSRQ of the device: when at least one of RSRP and RSRQ is below a respective (predefined or configured) threshold, it is assumed that the device is at the cell edge. Otherwise it is assumed that the device is in the inner region of the cell.

- In some embodiments, the decision whether or not the device is at the cell edge, depends on TA, which is signaled from eNB to the device for UL transmission synchronization. It depends on the pathloss, and hence on the distance between eNB and the device. If it exceeds a predefined or configured value, it is assumed that the device is at the cell edge.

- The respective thresholds may be configured by eNB, and eNB can adjust them to allow inter-cell D2D operation for more or less devices based on the traffic load or other status of the cell; alternatively, some or all of the thresholds may be predefined.

- In some embodiments, a combination of the conditions for RSRP, RSRQ and TA have to be fulfilled in order to determine that the device is at the cell edge. In the following, RSRP/RSRQ/TA means any single or combined condition of these parameters.

When the device is in the inner region of the cell,

- The device may only send or monitor discovery signal using the discovery resource of its own cell;

- The device may receive and accept D2D link setup requests from a neighbor cell's device and it may request a D2D link setup to a neighbor cell's device. This is possible if the neighbor cell configured the same discovery resource as the own cell. However, the D2D between them can only operate in own cell's D2D resource.

- When the device is at the cell edge,

- The device is allowed to monitor also discovery signals of devices of the neighbor cell;

- The device may receive and accept D2D link setup requests from a neighbor cell's device and it may send link setup request to a neighbor cell's device;

- The device can link with neighbor cell's device in own cell's D2D resource or neighbor cell's D2D resource.

- If device A in cell#l is at the cell edge, and it wants to setup link with neighbor cell#2's device B (either based on an own request or on request of the neighbor cell's device), the devices A and B will coordinate on D2D resource based on their knowledge on available D2D resource e.g. obtained from resource utilization detection. The coordinated information varies depending on the interested neighbor cell device B's status :

- If the interested neighbor cell device B is at the cell edge of cell#2 as indicated by the discovery signal of device B or by the request of device B to set up D2D communication, it means that device B can use D2D resource of device A's cell. In this case, devices A and B can perform D2D communication using a D2D resource of cell#l or of cell#2. E.g., based on its detection, one of the devices may indicate the available D2D resources of both its own cell and the neighbor cell to the other device. For example, one device may send a request for D2D link setup indicating all candidates, i.e. all resources scheduled for D2D use by this device, while the other device selects from the indicated set of resources one or more resources or parts of it (them). E.g. , the selection may be based on interference status on the indicated resources observed at the side of the other device. Then, the other device may inform the requestor. In another embodiment, the requestor may simply select a certain of his scheduled D2D resources and indicate it to the other device without leaving a selection to the latter device.

- If the interested neighbor device B is in the inner region of cell#2 as indicated by the discovery signal of device B, it means that device B can only use D2D resource of its own cell#2. , In this case, devices A and B can perform D2D communication using only in the D2D resource of cell#2. E.g. based on its detection, device A will indicate the available D2D resource of neighbor cell#2.

- Based on the coordination, devices A and B determine the resource for their D2D communication; if the used resource is not reserved for D2D in cell#l, device A informs its eNB: The information to eNB may include the resource used by device A. In addition, in some embodiments, it may also include the resource used by other devices detected by device A, and the cell-ID of the device paired with A (i.e., to which the D2D communication is established). Such information may help the eNB's scheduling for interference avoidance. In some embodiments, eNB may deny or confirm the D2D operation, or it may handover device A to neighbor ceil.

Thus, it is defined, under what condition the inter-cell D2D operation is allowed. Furthermore, D2D coordination signaling and signaling to eNB are functionally defined. Obvious interference to macro network is avoided since harmful D2D operation which may cause large interference to macro network is avoided. Device power is saved since unnecessary discovery operation is avoided.

One embodiment for the proposed D2D control is shown in Fig. 2 which shows two cells #1 and #2 and UEs A to D. In each cell there are two regions (cell edge and inner region) with different D2D operations allowed in each region. The respective region sizes may be configurable. The different options for the UEs in the different regions are indicated in the Figure. Fig. 3 shows examples of inter-cell D2D operation according to embodiments of the invention.

In example A (left part of Fig. 3), device A is in cell edge of cell#l, and device B is in cell edge of celi#2. D2D resource reserved in cell#l is SI, and D2D resource reserved in ceil#2 is S2, and SI may or may not overlap with S2. SI and S2 are known to both eNBs.

Firstly, device A and B will perform RSRP/RSRQ/TA measurement and compare with the threshold(s). The threshold(s) are preferably configured by the respective eNBs. Thus, by adjusting the configuration of the threshold(s), the e B can determine the range of inter-cell D2D operation, and determine in which region the devices can have the inter-cell D2D operation. The threshold values may be different in cell#l and cell#2. It depends on the respective eNB's decision made according to the cell status.

In example A, both devices A and B are at the cell edge and may monitor the discovery signal of the device of the neighbor cell. Then device A's discovery operation may include : send discovery signal, monitor the discovery signal from devices of own cell#l, monitor discovery signal of devices of neighbor cell#2, and device B may perform a corresponding operation.

Then device A detects device B due to its discovery signal and requests for link setup. If device A learns from the discovery signal of device B that device B is also at the cell edge (of cell#2), according to the inter-cell D2D operation, device B can use cell# l's resource for D2D with device A. When device A suggests resource for D2D operation with B, it can suggest both D2D resource in cell#l and D2D resource in cell#2, e.g. based on its detection results on resource utilization.

If devices A and B decide to operate in cell#2's D2D resource (or part of it) and this resource is not reserved for D2D in ceil#l, e.g. the white block in left figure, no signaling from device B to cell#2 eNB is needed, but device A has to inform the cell#l eNB that it will use some non-D2D resource (of cell#l) for D2D connection with device B from cell#2. In such a case, in some embodiments, the eNB of cell#l may have to confirm the D2D link setup. Furthermore, it may put scheduling restrictions to macro UEs near the cell-edge between cell#l and cell#2.

If, in another case, the resource used for D2D between devices A and B are some overlapped D2D resource in cell#l and cell#2, e.g. the black block as shown in the left part of the figure, then no signaling is needed to any of the eNBs.

In example B of the embodiment shown in Fig. 3 (right part), D2D resources reserved in cell#l and cell#2 do not overlap. Device A is in cell- edge of cell#l, but device B of cell#2 is not in celi-edge (in the inner region, based on RS P/RSRQ/TA measurement). Device A monitors device B's discovery signal, but device B does not monitor device A's discovery signal.

Then device A detects device B and asks for link setup. From the macro status indication in device B's discovery signal, device A knows that device B is in the inner region of cell #2may only use cell#2's D2D resource for the link. Then device A suggests some D2D resource reserved in cell#2 for D2D use, e.g. based on some measurement. Finally, the devices A and B decide to operate in the black resource as shown in the right part of the Figure.

In some embodiments, device A informs the eNB on the resource selected for D2D. It may also indicate to eNB the resource utilization by adjacent other devices, e.g. device C which it may have detected. Such information may help eNB to put scheduling restrictions for interference avoidance.

Fig. 4 shows an apparatus according to an embodiment of the invention. The apparatus may be a device such as a user equipment or a part thereof. Fig. 5 shows a method according to an embodiment of the invention. The apparatus according to Fig. 4 may perform the method of Fig. 5 but is not limited to this method. The method of Fig. 5 may be performed by the apparatus of Fig. 4 but is not limited to being performed by this apparatus.

The apparatus comprises assignment getting means 10, determining means 20, D2D detecting means 30, D2D communication means 40, and resource monitoring means 50. The assignment getting means 10 gets an assignment of resources to be used for D2D from the eNB, the apparatus is attached to (S10). The determining means 20 determines if the apparatus is at the cell edge, e.g. by evaluating if RSRP/RSRQ/TA are below/above a threshold (S20). The DTD detecting means 30 may receive a request from the other device to set up a D2D communication (S30). In some embodiments, steps S10, S20, and S30 may be interchanged.

If the apparatus is not at the cell edge (S40, no), the D2D communication means 40 may set up a D2D communication with the other device using the assigned resource (S50).

If the apparatus is at the cell edge (S40, yes), the monitoring means 50 monitors which resource is assigned for D2D for the other device (S60). Then, the D2D communication means 40 may set up a D2D communication with the other device using its own assigned D2D resource or the resource assigned to the other device (S70). Fig, 6 shows an apparatus according to an embodiment of the invention. The apparatus may be a base station such as an elMB or a part thereof. Fig. 7 shows a method according to an embodiment of the invention. The apparatus according to Fig. 6 may perform the method of Fig. 7 but is not limited to this method. The method of Fig. 7 may be performed by the apparatus of Fig. 6 but is not limited to being performed by this apparatus.

The apparatus comprises assigning means 110 and broadcasting means 120. The assigning means 110 assigns to one or more devices of a cell of the apparatus a resource for D2D (S110). The broadcasting means 120 broadcasts information about the assigned resource together with the own cell Id to the devices. In addition, it broadcasts information about a D2D resource and its corresponding cell Id, which the apparatus received from another apparatus such as another eNB (S120).

Embodiments of the invention are described based on an LTE system but embodiments of the invention may be applied to other radio access technologies such as WiFi, WLAN, UMTS, HSPA, if they comprise both macro operation and D2D operation.

A device may be a user equipment, a terminal, a mobile phone, a laptop, a smartphone, a tablet PC, or any other device that may attach to the mobile network. A base station may be a NodeB, an eNodeB or any other base station of a radio network.

Devices may use the full resource assigned for D2D or only part of it.

If not otherwise stated or otherwise made clear from the context, the statement that two entities are different means that they are differently addressed in their respective network. It does not necessarily mean that they are based on different hardware. That is, each of the entities described in the present description may be based on a different hardware, or some or all of the entities may be based on the same hardware.

According to the above description, it should thus be apparent that exemplary embodiments of the present invention provide, for example a base station apparatus such as a NodeB or an eNodeB, or a component thereof, an apparatus embodying the same, a method for controlling and/or operating the same, and computer program(s) controlling and/or operating the same as well as mediums carrying such computer program(s) and forming computer program product(s). Furthermore, it should thus be apparent that exemplary embodiments of the present invention provide, for example a controller apparatus such as a user equipment, a UE, or a component thereof, an apparatus embodying the same, a method for controlling and/or operating the same, and computer program(s) controlling and/or operating the same as well as mediums carrying such computer program(s) and forming computer program product(s).

According to exemplarily embodiments of the present invention, a system may comprise any conceivable combination of the thus depicted devices/apparatuses and other network elements, which are configured to cooperate with any one of them.

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

Generally, any structural means such as a processor or other circuitry may refer to one or more of the following : (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. Also, it may also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware, any integrated circuit, or the like.

Generally, any procedural step or functionality is suitable to be implemented as software/firmware 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, 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-Transistor Logic), etc., using for example ASIC (Application Specific IC (Integrated Circuit)) components, FPGA (Fieid-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, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device/apparatus or module, instead of being hardware implemented, be 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 cooperation with each other or functionally independently of each other but in a same device housing, for example. Apparatuses 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 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 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.

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

It is to be understood that what is described above is what is presently considered the preferred embodiments of the present invention. However, it should be noted that the description of the preferred embodiments is given by way of example only and that various modifications may be made without departing from the scope of the invention as defined by the appended claims.

Claims

What is claimed is:

1. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

at least one interface configured for communication with at least a base station and another apparatus,

the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform :

getting an assignment of a first resource usable for device-to-device communication from the base station;

determining a cell edge condition of the apparatus, which is only fulfilled if the apparatus is determined to be at an edge of a cell of the base station to which the apparatus is attached;

detecting a request from the other apparatus for setting up a device- to-device communication;

if the cell edge condition is not fulfilled : determining to set up the device-to-device communication to the other apparatus using at least a first part of the first resource only; and

if the cell edge condition is fulfilled:

monitoring an assignment of a second resource for device-to-device communication of the other apparatus, and

determining to set up the device-to-device communication to the other apparatus using at least one of a second part of the first resource and a part of the second resource.

2. The apparatus according to claim 1, wherein the at (east one processor, with the at least one memory and the computer program code, further being arranged to cause the apparatus to perform :

determining to send a discovery signal and/or to send a setup request to set up a communication to the other apparatus, wherein at least one of the discovery signal and the setup request comprises an edge condition information about the cell edge condition.

3. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

at least one interface configured for communication with at least a base station, and another apparatus,

determining to send a discovery signal and/or to send a setup request to set up a device-to-device communication to the other apparatus, wherein at least one of the discovery signal and the setup request comprises an edge condition information about the cell edge condition.

4. The apparatus according to any of claims 1 to 3, wherein it is determined that the apparatus is at the edge of the cell if at least one of the following conditions is fulfilled:

a reference signal received power from the base station is below a RSRP threshold value;

a reference signal received quality from the base station is below a RSRQ threshold value; and

a timing advance from the base station is above a TA threshold value.

5. The apparatus according to claim 4, wherein at least one of the RSRP threshold value, the RSRQ threshold value, and the TA threshold value is received from the base station, and/or wherein at least one of the RSRP threshold value, the RSRQ threshold value, and the TA threshold value is predefined.

6. The apparatus according to any of claims 1 to 5, wherein, if the cell edge condition is fulfilled, the at least one processor, with the at least one memory and the computer program code, further being arranged to cause the apparatus to perform :

monitoring if the other apparatus provides an information about a cell edge condition of the other apparatus; and

if the cell edge condition of the other apparatus is not fulfilled, determining to set up the device-to-device communication using at least the part of the second resource.

7. The apparatus according to any of claims 1 to 6, wherein the at least one processor, with the at least one memory and the computer program code, further being arranged to cause the apparatus to perform :

determining to send a resource information comprising at least one of an indication of the second resource, an indication of the used part of the second resource, and a cell identifier of a cell to which the other apparatus is attached to the base station if at least the part of the second resource is used for the device-to-device communication.

8. The apparatus according to any of claims 1 to 7, wherein the at least one processor, with the at least one memory and the computer program code, further being arranged to cause the apparatus to perform :

monitoring if the other apparatus is attached to the base station; and determining to set up the device-to-device communication to the other apparatus using the first resource only irrespective of the cell edge condition, if the other apparatus is attached to the base station.

9. A user equipment comprising the apparatus according to any of claims 1 to 8.

10. An apparatus, comprising

at least one processor,

at least one memory including computer program code, and

at least one interface configured for communication with at least a user equipment and another apparatus, the at least one processor, with the at least one memory and the computer program code, being arranged to cause the apparatus to at least perform :

determining to broadcast an information about a first D2D resource scheduled for use for a device-to-device communication by the user equipment attached to the apparatus and an information about a second D2D resource and a corresponding cell identification received from the other apparatus.

11. The apparatus according to claim 10, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform :

determining to provide a threshold information to the user equipment indicating at least one of a RSRP threshold value for a reference signal received power, a RSRQ threshold value for a reference signal received quality, and a TA threshold value for a timing advance with respect to the device-to-device communication.

12. The apparatus according to any of claims 10 and 11, wherein the at least one processor, with the at least one memory and the computer program code, is further arranged to cause the apparatus to perform :

determining to mitigate interference by rescheduling radio resources and/or disabling the device-to-device communication of the user equipment and/or initiating a handover of the user equipment if a resource information is received indicating that a third D2D resource not scheduled for the device-to-device communication is used or intended to be used for the device-to-device communication by the user equipment.

13. A base station comprising an apparatus according to any of claims 10 to 12.

14. A method, comprising

getting an assignment of a first resource usable for device-to-device communication from a base station; determining a cell edge condition, which is only fulfilled if an apparatus performing the method is determined to be at an edge of a cell of the base station to which the apparatus is attached;

detecting a request from another apparatus for setting up a device- to-device communication;

if the cell edge condition is fulfilled :

15. The method according to claim 14, further comprising :

determining to send a discovery signal and/or to send a setup request to set up a communication to the other apparatus, wherein at least one of the discovery signal and the setup request comprises an edge condition information about the ceil edge condition.

16. A method, comprising

getting an assignment of a first resource usable for device-to-device communication from a base station;

determining a cell edge condition of the apparatus, which is only fulfilled if an apparatus performing the method is determined to be at an edge of a cell of the base station to which the apparatus is attached;

determining to send a discovery signal and/or to send a setup request to set up a device-to device communication to the other apparatus, wherein at least one of the discovery signal and the setup request comprises an edge condition information about the cell edge condition.

17. The method according to any of claims 14 to 16, wherein it is determined that the apparatus is at the edge of the cell if at least one of the following conditions is fulfilled : a reference signal received power from the base station is below a RSRP threshold value;

a timing advance from the base station is above a TA threshold value.

18. The method according to claim 17, wherein at least one of the RSRP threshold value, the RSRQ threshold value, and the TA threshold value is received from the base station, and/or wherein at least one of the RSRP threshold value, the RSRQ threshold value, and the TA threshold value is predefined.

19. The method according to any of claims 14 to 18, further comprising, if the cell edge condition is fulfilled :

if the cell edge condition of the other apparatus is not fulfilled, determining to set up the device-to-device communication using at least the part the second resource.

20. The method according to any of claims 14 to 19, further comprising

21. The method according to any of claims 14 to 20, further comprising

monitoring if the other apparatus is attached to the base station; and determining to set up the device-to-device communication to the other apparatus using the first resource only irrespective of the ceil edge condition, if the other apparatus is attached to the base station.

22. A method, comprising determining to broadcast an information about a first D2D resource scheduled for use for a device-to-device communication by a user equipment attached to an apparatus performing the method and an information about a second D2D resource and a corresponding eel! identification received from another apparatus.

23. The method according to claim 22, further comprising

determining to provide a threshold information to the user equipment indicating at least one of a RSRP threshold value for a reference signal received power, a RSRQ threshold value for a reference signal received quality, and a TA threshold value for a timing advance with respect to a device-to-device communication.

24. The method according to any of claims 22 to 23, further comprising

25. A computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method according to any one of claims 14 to 24.

26. The computer program product according to claim 25, embodied as a computer-readable medium.