HK1220312B - A method and wireless device for providing device-to-device communication - Google Patents

Description

Method and wireless device for providing device-to-device communication

Technical Field

Embodiments herein relate to wireless communication systems, such as telecommunication systems. In particular, embodiments herein relate to direct communication between wireless devices.

Background Art

Device-to-device communication is a well-known and widely used component of existing wireless technologies, including ad hoc and cellular networks. Examples include Bluetooth and various variations of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard series, such as WiFi Direct. These systems operate in the unlicensed spectrum.

Recently, device-to-device (D2D) communications as an underlying layer of cellular networks have been proposed as a means to exploit the proximity of communicating devices while allowing the devices to operate in an interference-controlled environment. Typically, such device-to-device communications are proposed to share the same spectrum as the cellular system, for example by reserving some cellular uplink resources for device-to-device purposes. Allocating dedicated spectrum for device-to-device purposes is unlikely to be an alternative, as spectrum is a scarce resource and (dynamic) sharing between device-to-device services and cellular services is more flexible and provides higher spectrum efficiency. D2D communications in cellular networks are often defined as direct communications, and the mechanisms for controlling such communications are defined as direct control (DC).

Devices that want to communicate directly, or even simply discover each other, typically need to transmit various forms of control signaling. One example of such direct control signaling is a so-called beacon signal, which carries at least some form of identification and is transmitted by a device that wants to be discoverable by other devices. Other devices can scan for this beacon signal. Once a device has detected a beacon, it can take appropriate action, such as attempting to initiate a connection with the device that transmitted the beacon.

Multiple devices can transmit control signaling (beacon signals and other types of control signaling) simultaneously. Transmissions from different devices can be synchronized (time-aligned with each other) or asynchronous in time. Synchronization can be achieved, for example, by receiving appropriate signals from an overlying cellular network or from a global navigation satellite system such as GPS. An example of asynchronous beacon reception occurs when a nearby wireless device belongs to an adjacent, asynchronous cell.

Figure 4 illustrates an example of DC message reception in an asynchronous scenario. The receiver requires multiple, possibly overlapping, receive windows and corresponding parallel FFT processing. Direct control signaling can include DC messages, beacons, etc.

In order to reduce device power consumption, discontinuous reception (DRX) is typically used. With DRX, the device is dormant most of the time but wakes up regularly (occasionally) to check for transmissions expected for the device.

Multiple asynchronous transmissions of control signaling lead to several problems:

Since the likely times at which a (control signaling) transmission may occur are not known, each device needs to wake up frequently to check for transmissions, with a corresponding negative impact on power consumption. This is particularly problematic for beacons, which are expected to transmit infrequently (with periods on the order of seconds) and can significantly impact discovery latency if their reception is missed.

• Receiving multiple non-synchronized and partially overlapping transmissions requires multiple FFTs, which increases device complexity and is associated with strong inter-message interference and near-far problems.

The ability to multiplex multiple transmissions is generally degraded without time synchronization.

Furthermore, it may not be possible to receive a weak message in time when a strong message is received on a resource that partially overlaps in time. This is because the automatic gain control at the receiver is typically adjusted based on the strongest signal and is largely suboptimal for weak signals.

Multiplexing control signaling from multiple devices can be accomplished in a variety of ways, such as using time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA). The choice and/or details of the multiplexing scheme depend on whether the devices are time synchronized. Figure 1 illustrates an example of TDMA multiplexing of DC messages within a single direct control DC resource. Figure 2 illustrates an example of FDMA multiplexing of DC messages within a single DC resource. Figure 3 illustrates an example of CDMA multiplexing of DC messages within a single DC resource.

A number of different transmission schemes for control signaling are conceivable. One possibility is OFDM and its derivatives, such as Discrete Fourier Transform (DFT) precoded Orthogonal Frequency Division Multiplexing (OFDM), which allow for low-complexity and efficient receiver implementations using Fast Fourier Transforms (FFTs).

Summary of the Invention

One object is to improve direct control signaling, eg to increase the probability of successful reception of direct control signaling, such as DC messages of the type mentioned above.

According to one aspect of the present disclosure, it relates to a method for assigning resources for direct control signaling performed in a radio node. The method includes receiving a set of resources for direct control signaling in a corresponding cell or cluster from at least one other radio node. The method further includes assigning resources for direct control signaling transmission within an area controlled by the radio node based at least on the received set of resources. The method further includes transmitting a message indicating the assigned resources for direct control signaling to a wireless device controlled by the radio node. The proposed solution enables synchronization of direct control DC resources, whereby multiple DC messages can be received within the same receive window, which reduces the need for multiple receive windows and correspondingly improves energy consumption and interference.

Furthermore, when attempting to receive a DC message transmitted from a UE camped on another cell, the probability of receiving multiple DC messages within the same receive window is increased. This reduces the complexity of the receiver implementation since each receive window typically requires a single FFT process.

Assuming that UEs belonging to the same cell have relatively similar path losses for a given UE, it is easier for the receiver to set the AGC for each subframe and safely decode the DC message multiplexed within the subframe.

According to one aspect, the message indicates the respective resources assigned for direct control signaling within each of the cell or cluster and at least one additional cell or cluster defined by the radio node. A wireless device may need to receive control signaling related to neighboring devices regardless of whether those devices are located in the same network cell as the first device. In other words, from a device-to-device communication perspective, there are no cell boundaries.

According to one aspect, the step of receiving includes negotiating resources for direct control signaling with at least one other radio node, thereby increasing the overlap in time and/or frequency of resources used for direct control signaling in different cells or clusters.Such a solution makes DTX more efficient.

According to one aspect, the step of receiving comprises negotiating resources for direct control signaling with at least one other radio node, thereby reducing overlap in time and/or frequency of resources used for direct control signaling in different cells or clusters.Such a solution may prevent interfering transmissions.

According to one aspect, the assigning includes assigning resources for D2D discovery signaling.Thus, the wireless device only needs to listen to discovery messages or beacons at predetermined times.

According to one aspect, the message comprises at least one identifier for a cell or a cluster defined by the radio node.

According to one aspect, the resource is a radio resource, a resource block, a subframe or a subchannel.

According to one aspect, the radio node is a wireless device having authority to control one or more other wireless devices in D2D communication, and the method further comprises sending a second direct control message to the wireless device using the assigned resources.

According to one aspect, the step of assigning comprises assigning resources that occur periodically on a per radio frame basis.

According to one aspect, the disclosure further relates to a computer program comprising computer program code which, when executed in a radio node, causes the radio node to perform the method described above.

According to one aspect, the present disclosure further relates to a method, performed in a D2D device-to-device communication, for obtaining resources for direct control signaling in D2D communication. The method includes receiving a message from a radio node indicating resources assigned to a wireless device controlled by the radio node for direct control signaling, and utilizing the indicated resources for direct control signaling.

According to one aspect, the message indicates respective resources for direct control signaling within each of a cell or cluster defined by the radio node and further cells or clusters defined by further radio nodes.

According to one aspect, the step of utilizing further comprises receiving a second message using the indicated resources.

According to one aspect, the step of utilizing further comprises transmitting a third message using resources provided in the received message.

According to one aspect, the second and third messages are separated by time division multiple access (TDMA), code division multiple access (CDMA), or frequency division multiple access (FDMA).

According to one aspect, the method further comprises selecting at least one indicated resource for monitoring.

According to one aspect, the method further includes determining a discontinuous reception (DRX) cycle of the wireless device using information included in the received message.

According to one aspect, the present disclosure further relates to a computer program comprising a computer program code which, when executed in a wireless device, causes the wireless device to perform the method described above.

According to one aspect, the present disclosure further relates to a radio node configured to assign resources for direct control signaling. The radio node includes a transmitter, a receiver, and processing circuitry. The processing circuitry is configured to cause the radio node to receive, using the receiver, a set of resources for direct control signaling in a corresponding cell or cluster from at least one other radio node, assign resources for direct control signaling based on the received set of resources, and transmit, using the transmitter, a message indicating the assigned resources for direct control signaling to a wireless device controlled by the radio node, wherein the radio node is a radio network node.

According to an aspect, the radio node is a radio network node.

According to one aspect, the radio node is a wireless device having authority to control one or more other wireless devices.

According to one aspect, the present disclosure further relates to a wireless device configured to obtain resources for direct control signaling. The wireless device includes a transmitter, a receiver, and processing circuitry. The processing circuitry is configured to cause the wireless device to receive, using the receiver, a message from a radio node indicating resources for direct control signaling assigned to a wireless device controlled by the radio node, and to utilize the indicated resources for direct control signaling using the receiver and/or the transmitter.

Advantageously, at least some embodiments herein allow a UE to increase the DRX cycle when a cluster head is available and simplify UE implementation for at least NW coverage scenarios as well as no NW coverage scenarios. Inter-beacon interference is also reduced as an example of direct control signaling for inter-cell discovery.

It is an object according to the present embodiments to alleviate at least some of the problems mentioned above.A further object according to some embodiments is to provide a mechanism that enables synchronization in device-to-device communications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an example of TDMA multiplexing of Direct Control (DC) messages within a single DC resource.

FIG2 is an example of FDMA multiplexing of DC messages within a single DC resource.

FIG3 is an example of CDMA multiplexing of DC messages within a single DC resource.

FIG4 is an example of DC message reception in an asynchronous scenario.

5a-5d depict an exemplary radio communication system 100 in which embodiments herein may be implemented.

6-6b illustrate exemplary methods in a radio node as flow charts.

FIG7 illustrates, as a flow chart, an exemplary method in a wireless device.

FIG8 illustrates signaling exchanged between a radio node and a wireless device when performing the method.

FIG. 9 illustrates the DC bandwidth available for assignment for an example DC message.

FIG10 illustrates an example in which the receiver maximizes the DRX duty cycle without the risk of missing a DC message.

FIG11 is a schematic block diagram of a radio node.

FIG12 is a schematic block diagram of a wireless device.

DETAILED DESCRIPTION

The proposed technology is based on the understanding that a UE or wireless device generally needs to receive control signaling from neighboring devices, regardless of whether those neighboring devices are located in the same network cell as the UE. In other words, from a device-to-device communication perspective, there are no cell boundaries. Also of interest is extending D2D to multi-carrier and multi-operator scenarios.

According to one aspect, the object may be achieved by a method in a radio node for allocating resources for direct control signaling in D2D communication.A corresponding method in a wireless device, such as a second wireless device, for obtaining resources for direct control signaling in D2D communication is also provided.

This disclosure proposes a method for resource allocation for the purpose of directly controlling discovery. This method allows for efficient UE implementation (less parallel FFT processing, simpler AGC). Some embodiments also propose signaling of multi-cell discovery resources. According to some embodiments herein, multiple DRX cycles are defined to efficiently support both network (NW) coverage and no-coverage scenarios.

Throughout the following description, like reference numerals are used to denote like components, network nodes, parts, features, where applicable.

As used herein, the terms "number" and "value" may be any type of number, such as binary, real, imaginary, or rational numbers. Furthermore, a "number" and "value" may be one or more characters, such as a letter or a string of letters. A "number" and "value" may also be represented by a string of bits.

FIG5 a illustrates an exemplary radio communication system 100 in which the proposed technology may be implemented. In this example, the radio communication system 100 is a Long Term Evolution (LTE) system. In other examples, the radio communication system may be any Third Generation Partnership Project (3GPP) cellular communication system, such as a Wideband Code Division Multiple Access (WCDMA) network, a Global System for Mobile Communications (GSM) network, or an evolution of any of the above systems.

Radio communication system 100 includes a radio network node 130. As used herein, "radio network node" may refer to an evolved Node B (eNB), a control node controlling one or more remote radio units (RRUs), a radio base station, an access point, and the like. Radio network node 130 may be configured to operate within a so-called system bandwidth. A portion of this system bandwidth may be statically or dynamically reserved for D2D communication. Thus, the DC bandwidth, as shown in FIG9 , may be used to allocate, for example, DC messages.

The radio network node 130 may operate the cell C1. More generally, the cell C1 may be comprised in the radio communication system 100.

Furthermore, as shown in FIG5 a, the first wireless device 100 may be located within cell C1, for example, within range of communication with the radio network node 130. As used herein, the term "wireless device" may refer to a user equipment, a mobile phone, a cellular phone, a personal digital assistant equipped with radio communication capabilities, a smartphone, a laptop or personal computer (PC) equipped with an internal or external mobile broadband modem, a tablet PC with radio communication capabilities, a portable electronic radio communication device, a sensor device equipped with radio communication capabilities, and the like. The wireless device is configured for D2D communication. The sensor may be any type of weather sensor, such as wind, temperature, air pressure, humidity, and the like. As another example, the sensor may be a light sensor, an electronic switch, a microphone, a speaker, a camera sensor, and the like.

In another example, as shown in FIG5 b , the wireless device 110 may be located outside of the cell C1, i.e., out of coverage for communicating with the radio network node 130. In such a scenario, the wireless device 110 provides synchronization of device-to-device communications. From now on, we will refer to such devices as being controlled by the wireless device 110. These devices may be referred to as belonging to a cluster.

Furthermore, the second wireless device 120 may be within range for D2D communication with the first wireless device 110. As shown in Figures 5c and 5a, respectively, the second wireless device 120 may or may not be located within the cell C1.

Additionally, the third wireless device 140 may be within range of the first or second wireless device for D2D communication. The third wireless device 140 may or may not be located within the cell C1.

According to the proposed technique, the radio network node 130 or the first wireless device 110 may assign resources 150 for direct control signaling.

Figure 8 illustrates an exemplary method in a radio network node 130 or a wireless device 110 according to embodiments herein. The radio network node 130 and the wireless device 110 will be referred to as radio node 101 in the following description where applicable.

Radio node 101 may execute a method for allocating resources for direct control signaling in D2D communication. The radio node may be a radio network node 130 or a so-called cluster head, which may be a wireless device 110 with certain permissions to control one or more other wireless devices, such as the second and third wireless devices 120 and 140, in D2D communication. The devices controlled by the cluster head are referred to as a cluster. Such a scenario is illustrated in FIG5b , where the wireless device is typically out of coverage of a cellular network or the cellular network is experiencing a failure. The resources may be radio resources, resource blocks, subframes, subchannels, etc. An example of direct control signaling is the aforementioned DC message.

The following description is intended to describe the proposed technique in general. Therefore, coverage or no coverage is considered, which means that the principle can be applied in the different situations shown in Figures 5a to 5d. The following actions or signals visually represented in Figure 8 can be performed in any appropriate order.

Action P01

The radio node 101 sends a first message P01 to the second and third wireless devices, indicating resources for direct control signaling. These resources are typically intended for direct control by wireless devices residing on or controlled by a network node. Resources are typically defined by time and frequency. Therefore, wireless devices in a cell or cluster will use this window for direct control transmissions. These devices will also need to monitor this window to discover other wireless devices in the cell or cluster.

The indicated resources are synchronized in the time domain with respect to a reception window, such as a subframe in LTE. In this way, the radio node assigns resources for direct control signaling. The occurrence of the resources can be periodic, for example, on a per-radio-frame basis, or sparse in time.

In some examples, as shown in FIG. 5 d , the first wireless device 110 is camping on cell C1 and the second and third wireless devices 120 , 140 are camping on other cells.

The receiving window may include one or more subframes according to the number of direct control signalings, that is, the number of DC messages to be assigned to the resources provided in the receiving window or carried by the resources.

According to one aspect, referring also to FIG. 9 , the first message indicates respective resources used for direct control signaling in, for example, the cell and each of the further cells.

In this case, the wireless device is discovering or communicating with another wireless device belonging to a different cell on the same carrier and PLMN. This communication may be done over an interface 170 between the two eNodeBs, which is called the X2 interface.

Note that neighboring cells may or may not be synchronized at the subframe level. Note also that inter-cell coordination of direct control resources is not required. Therefore, the network node signals the resources for direct control signaling to be monitored, which correspond to the resources used for transmission by wireless devices residing on the neighboring cells.

The first message may also indicate identifiers of the cell and further cells, such as physical cell identities.

Action P02

The second wireless device 120 receives a second message, such as direct control signaling, a DC message, etc., from the first wireless device 110 in the reception window, for example.

Action P03

In addition, the second wireless device 120 receives a third message, such as direct control signaling, DC signaling, etc., from the third wireless device 140, for example, in the receive window. As shown in FIG8 , the third wireless device has subsequently received a similar message with information related to the window for transmission.

The second and third messages are thus received in the same receive window by the second wireless device 120. However, the second and third messages are separated within the receive window by TDMA, CDMA, FDMA, etc.

According to the second embodiment, the second wireless device does not need to perform random access and RRC to obtain corresponding resources in each of the cell and the further cell, because this information is provided in the first message.

The second wireless device can use the identifiers of the cell and the additional cell to determine the corresponding DRX cycles in the cell and the additional cell. Thus, the number of FFTs required in the second wireless device 120 can also be determined. The second wireless device can then choose to wake up on a subset of the resources indicated in the first message. For example, the second wireless device can wake up at every resource instance related to the additional cell, while the second wireless device can only wake up on some resources related to cell C1. Thus, because the second wireless device can selectively and intentionally choose which resources to monitor for direct control signaling, the second wireless device can increase the sleep period in the DRX cycle without accidentally missing any direct control signaling.

It is generally assumed that the NW configures periodic (or sparse in time) resources for the transmission of direct control messages (DC). A beacon used to discover nearby devices is an example of a DC message. In the absence of coverage, two scenarios are considered:

A UE with special control authority, often called a Cluster Head (CH), assigns DC resources to other UEs.

• The UE autonomously decides which resources to use to transmit DC, which may be within a subset of pre-configured resources (eg, a certain subband).

Devices located within a small cell (residing on the same cell) typically derive synchronization from the downlink of that cell. This ensures that transmissions from different devices are synchronized in time, and therefore reception at a given device is approximately synchronized (the time difference is proportional to the distance and can be mitigated by the cyclic prefix in OFDM). A similar situation may occur in a no-coverage scenario, where a UE can synchronize with a CH UE.

A corresponding method of assigning resources for direct control signaling performed in the radio node 101 will now be described in more detail with reference to Figure 6. According to one aspect, the assigned resources are radio resources, resource blocks, subframes or subchannels.

In a first step S1 , the radio node 101 receives a set of resources for direct control signaling in a respective cell or cluster from at least one further radio node.As described above, the present disclosure is based on synchronization between neighboring radio nodes.

In a second step S2, the radio node 101 assigns resources for direct control signaling transmission within the area controlled by the radio node based at least on the received resource set. According to one aspect, assigning S2 includes assigning resources for D2D discovery signaling. Different strategies can be used for this purpose depending on the situation. However, it is possible that the resource set received S1 is utilized, for example, to optimize a sleep period in a DTX mode.

In an alternative embodiment shown in Figure 6b, step S1 is omitted. The assignment of resources S2 is then based on, for example, measurements or other assumptions. In principle, the resources can be pre-programmed in the radio node, where the same time and frequency are always used.

In a third step S3, the radio node 101 transmits a message P01 to the wireless devices controlled by the radio node, indicating the resources assigned for direct control signaling. For example, referring to FIG9 , the radio node indicates a window for direct control transmissions to be used by wireless devices residing in the cell. This transmission can be a broadcast transmission to all wireless devices in the cell or cluster. Alternatively, the message can be directed to one or more specific wireless devices or user equipment (UEs). Consequently, as shown in FIG9 , different UEs can be assigned different resources, with UEs A, B, and C being allocated temporally different resources.

According to one aspect, the message indicates the respective resources assigned for direct control signaling in each of the cell C1 or cluster and at least one additional cell C2 or cluster defined by the radio node 101. Thus, as described, as shown in Figures 9 and 10 , a first tx window used by wireless devices in cell C1 and a second tx window used by wireless devices in cell C2 are indicated for the cell and additional cells. As described above, wireless devices can communicate with devices within or outside of a cell or cluster. Therefore, within cell C1, an indication of the resources assigned for direct control signaling in a neighboring cell C2 or cluster may also be relevant. Thus, a wireless device residing on cell C1 typically uses one transmission window 91 for direct control transmissions, such as beacons, but may wish to view both transmission windows 91 and 92 for discovery purposes.

The above embodiments are described in more detail below. Several aspects are possible and can be used individually or in combination. In a first embodiment, the network or the Channel assigns DC resources to increase—such as maximize—reuse of each subframe and to use as few subframes as possible for DC.

Figure 9 illustrates an example of synchronous multiplexing of DC messages within each cell (or CN). Compared to the asynchronous case with the same number of DC messages, the number of required receive windows and parallel FFT processing is smaller.

In each subframe, the DC message can be multiplexed, for example, via TDMA, FDMA or CDMA. This solution has several advantages, such as:

Receiving multiple DC messages within the same receive window reduces the need for multiple receive windows and correspondingly improves energy consumption and interference;

When attempting to receive a DC message transmitted from a UE camped on another cell, the probability of receiving multiple DC messages within the same receive window is increased. This reduces the complexity of the receiver implementation, since each receive window typically requires a single FFT process.

Assuming that UEs belonging to the same cell have relatively similar path losses for a given UE, it is easier for the receiver to set the AGC for each subframe and securely decode the DC message multiplexed within the subframe.

According to a second embodiment shown in FIG10 , the network informs the device of the timing and/or frequency association of the DC resources of the neighboring cells with the reference timing and frequency of the cell in which it resides.

Figure 10 illustrates an example of synchronous multiplexing of DC messages within each cell (or CH). Signaling the time (and/or frequency) offset associated with DC signaling in neighboring cells and/or CHs allows the receiver to maximize the DRX duty cycle without the risk of missing DC messages.

One possibility is to provide this information in the form of a list of physical cell identifiers and the corresponding time and/or frequency differences relative to the cell in which the device is residing. The device can then use this information to determine the DRX cycle and the number of FFTs required. In another example, when a UE enters a new tracking area, it is provided with DC resources for each cell in the tracking area. This is to avoid the UE having to perform random access and RRC reconfiguration to acquire DC resources whenever it changes cells within the tracking area.

In order to implement the above embodiments, different eNBs in the network need to signal the set of resources used for DC in each cell. As described above, the network node receives this signaling in step S1. Possibly, the eNB can negotiate such resources in order to increase the overlap of DC resources in different cells in time and/or frequency. Therefore, according to one aspect, the receiving step S1 includes negotiating S1a with at least one other radio node for resources for direct control signaling, thereby increasing the overlap of resources for direct control signaling in different cells or clusters in time and/or frequency. According to one aspect, the message includes at least one identifier of a cell C1 or cluster defined by the radio node 101.

By adjusting the number of cells (or cell clusters) that the device considers when setting the DRX cycle, it is also possible to balance power consumption with the likelihood of detecting devices in neighboring cells. Increasing the number of cells that the device monitors for other device control signaling (with different timing than the serving cell) means waking up from DRX more frequently and increasing power consumption. One possibility is to configure the UE to wake up systematically to receive DCs in its own cell, and only wake up for a subset of DCs associated with neighboring cells. This solution will result in greater discovery latency for UEs in neighboring cells.

According to an alternative aspect, the step S1 of receiving comprises negotiating S1b with at least one other radio node resources for direct control signaling, thereby reducing overlap in time and/or frequency of resources for direct control signaling in different cells or clusters.

According to one aspect, radio node 101 is a wireless device 110 that has some authority to control one or more other wireless devices 120, 140 in D2D communications. Therefore, the method further includes sending S4 a second direct control message to the wireless device using the assigned resources. This refers to the case where the radio node is a "cluster head." Wireless device 101 can therefore first assign direct control resources and then utilize them.

According to one aspect, as explained above, the step S2 of assigning comprises assigning resources that occur periodically on a per radio frame basis.

According to one aspect, the present disclosure relates to a computer program comprising computer program code which, when executed in the radio node 101 , causes the radio node 101 to perform the method.

A corresponding method performed in a wireless device to obtain resources for direct control signaling in D2D communication will now be described in more detail with reference to FIG. 7 .

In a first step, the wireless device receives S11 a message P01 from the radio node 101 indicating resources assigned for direct control signaling to the wireless device controlled by the radio node 101. This step thus corresponds to step S3 in Figure 6 or message P01 in Figure 8 .

In a second step, the wireless device utilizes the resources indicated in S 13 for direct control signaling. The indicated resources are, for example, resources to be used for direct control transmission in a certain cell or cluster.

According to one aspect, the message indicates the respective resources used for direct control signaling in each of the cell C1 or cluster defined by the radio node 101 and the further cell C2 or cluster defined by the further radio node 160. Referring again to FIG. 5 d , direct control between wireless devices residing on different cells is a possible scenario. Therefore, the radio node then needs to signal not only its own direct control resources, but also the direct control resources of neighboring cells, as wireless devices may also want to view these resources.

According to one aspect, the step S13 of utilizing further comprises receiving the P02 second message using the indicated resources.Thus, since the wireless device knows which resources to listen to, it can receive data using the indicated resources.

According to one aspect, the step S13 of utilizing further comprises transmitting a P03 third message using the resources provided in the received message.

According to one aspect, the second and third messages are separated by time division multiple access TDMA, code division multiple access CDMA or frequency division multiple access FDMA as explained above with respect to FIG. 4 .

According to an aspect, the method further comprises selecting S12 at least one indicated resource for monitoring.

According to one aspect, the method further comprises determining S14 a discontinuous reception (DRX) cycle of the wireless device using information included in the received message.

In another embodiment, the UE adopts different DRX duty cycles depending on whether it is under NW coverage or outside NW coverage. Possibly, another DRX duty cycle may be selected when the UE is outside NW coverage but associated with a CN. In one example, an idle UE wakes up only for D2D DC reception at time (and frequency) resources signaled by the network (such resources may include DC resources for multiple cells). However, when an idle UE loses NW coverage, it becomes always awake and tracks all resources preconfigured for DC, at least until it successfully establishes a connection with the CN. After connecting to the CH, the CH may signal a new DRX cycle. DRX for D2D and DC reception purposes can be merged with the DRX cycle for cellular communication purposes. For example, a condition can be defined so that the UE wakes up when either the cellular or D2D DRX cycle indicates an awake state.

According to one aspect, the present disclosure further relates to a computer program comprising computer program code which, when executed in a device-to-device D2D device 120 , 140 , causes the wireless device 120 to perform a method in the wireless device.

11 , a schematic block diagram of a first wireless device 110 is shown. The first wireless device 110 is configured to perform the methods of FIG6 and FIG8 . The first wireless device 110 is configured to manage resources allocated for broadcasting data. More generally, the description in conjunction with FIG11 also applies to the radio node 101.

The first wireless device 110 includes a processing circuit 410 configured to perform the methods in Figures 6 and 8. More specifically, the processing circuit 410 is configured to cause the radio node 101 to:

receiving, using a receiver, from at least one further radio node 160 a set of resources for direct control signaling in the respective cell or cluster,

Allocating resources for direct control signaling based on the received resource set;

• transmitting, using a transmitter, a message indicating resources assigned for direct control signalling to a wireless device controlled by the radio node. The method according to any preceding claim, wherein the radio node 101 is a radio network node 130.

The processing circuit 410 may include a determination unit, a calculation unit, a selection unit, etc. as required to implement the embodiments herein. In particular, the processing circuit 410 may include a receiver module 410a configured to receive, using a receiver, a set of resources for direct control signaling in a corresponding cell or cluster from at least one further radio node 160. It may further include an allocator 410b configured to assign resources for direct control signaling based on the received set of resources; and a transmitter module 410b configured to transmit, using a transmitter, a message indicating the resources assigned for direct control signaling to a wireless device controlled by the radio node. The method according to any preceding claim, wherein the radio node 101 is a radio network node 130.

The processing circuit 410 may be a processing unit, a processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc. As an example, a processor, an ASIC, an FPGA, etc. may include one or more processor cores.

The first wireless device 110 further includes a transmitter 420, which may be configured to transmit one or more numbers, values, or parameters described herein.

The first wireless device 110 further includes a receiver 430 , which may be configured to receive one or more numbers, values, or parameters described herein.

The first wireless device 110 further includes a memory 440 for storing software to be executed by the processing circuit, for example. The software may include instructions that enable the processing circuit to perform the method in the wireless device 110 as described above in conjunction with FIG8 . The memory may be a hard disk, a magnetic storage medium, a portable computer cartridge or disk, a flash memory, a random access memory (RAM), etc. Alternatively, the memory may be an internal register memory of the processor.

Similar to the description above with reference to FIG11 , a second wireless device is provided. The second wireless device is configured to perform the actions described above with reference to the accompanying drawings. Therefore, referring to FIG12 , a schematic block diagram of a second wireless device 120 is shown. The second wireless device 120 is configured to obtain resources for direct control signaling.

The second wireless device 120 is configured to perform the methods of Figures 7 and 8. The second wireless device 120 is configured to receive the first message in order to be informed about resources used for direct control signaling.

The second wireless device 130 includes a processing circuit 510 configured to perform the method in Figure 8. In particular, the second wireless device is configured to:

receiving, using a receiver, a message from the radio node 101 indicating resources assigned for direct control signalling to a wireless device controlled by the radio node 101, and

• Utilize the indicated resources for direct control signaling using the receiver 530 and/or transmitter 520.

The processing circuit 410 may include a determination unit, a calculation unit, a selection unit, etc. as required to perform the embodiments herein. In particular, the processing circuit 510 may include a receiver module 510a configured to receive a message indicating resources assigned to a wireless device controlled by the radio node 101 for direct control signaling from the radio node 101 using a receiver; and a utilizer 510b configured to utilize the indicated resources for direct control signaling using a receiver 530 and/or a transmitter 520.

The processing circuit 510 may be a processing unit, a processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc. As an example, a processor, an ASIC, an FPGA, etc. may include one or more processor cores.

The second wireless device 120 further includes a transmitter 520, which may be configured to transmit one or more numbers, values, or parameters described herein.

The second wireless device 120 further includes a receiver 530 , which may be configured to receive one or more numbers, values, or parameters described herein.

The second wireless device 120 further includes a memory 540 for storing software to be executed by the processing circuit, for example. The software may include instructions that enable the processing circuit to perform the method in the second wireless device 120 as described above in conjunction with FIG8 . The memory may be a hard disk, a magnetic storage medium, a portable computer card or disk, a flash memory, a random access memory (RAM), etc. Alternatively, the memory may be an internal register memory of the processor.

Although various embodiments have been described, many different changes, modifications, etc. will become apparent to those skilled in the art. Therefore, the described embodiments are not intended to limit the scope of the present disclosure.

Claims (19)

1. A method for assigning resources for device-to-device discovery signaling, performed in radio nodes (110, 130), the method comprising: A set of resources for device discovery signaling is received (S1) from at least one other radio node (130'). Resources for device-to-device discovery signaling transmissions within the area controlled by the radio node are assigned, at least based on the set of received resources; and A message (P01) is transmitted (S3) to the wireless device controlled by the radio node, indicating the corresponding resources assigned for device-to-device discovery signaling in the cell (C1) or cluster defined by the radio node (110, 130) and at least one other cell (C2) or cluster. 2. The method of claim 1, wherein the receiving step (S1) includes negotiating (S1a) with at least one other radio node for resources for device-to-device discovery signaling, thereby increasing the overlap in time and/or frequency of resources for device-to-device discovery signaling in different cells or clusters. 3. The method of claim 1, wherein the receiving step (S1) includes negotiating (S1a) with at least one other radio node for resources for device-to-device discovery signaling, thereby reducing the overlap in time and/or frequency of resources for device-to-device discovery signaling in different cells or clusters. 4. The method according to any one of the preceding claims, wherein the message includes at least one identifier for a cell (C1) or cluster defined by the radio nodes (110, 130). 5. The method according to any one of claims 1 to 3, wherein the resource is a radio resource, a resource block, a subframe, or a subchannel. 6. The method according to any one of claims 1 to 3, wherein the radio node (110, 130) is a wireless device (110) having authority to control one or more other wireless devices (120, 140) in D2D communication, and wherein the method further comprises: Use the assigned resources to send a (S4) device-to-device discovery message to the wireless device. 7. The method according to any one of claims 1 to 3, wherein the assignment (S2) step comprises assigning resources that appear periodically on a per radio frame basis. 8. A computer-readable medium storing computer program code that, when executed in a radio node (110, 130), causes the radio node (110, 130) to perform the method according to any one of claims 1-7. 9. A method for obtaining resources for device-to-device discovery signaling, executed in a device-to-device (D2D) device (120, 130), the method comprising: Receive (S11) a message (P01) from radio nodes (110, 130) indicating resources for device-to-device discovery signaling assigned to the wireless devices controlled by said radio nodes (110, 130), wherein said message indicates corresponding resources for device-to-device discovery signaling in each of the cells (C1) or clusters defined by said radio nodes (110, 130) and in other cells (C2) or clusters defined by other radio nodes (130'); and Utilize the resources indicated in (S13) for device-to-device discovery signaling. 10. The method of claim 9, wherein the step of utilizing (S13) further comprises using the indicated resource to receive (P02) the second message. 11. The method of claim 10, wherein the utilization (S13) step further comprises using the resources provided in the received message to transmit (P03) a third message. 12. The method of claim 11, wherein the second message and the third message are separated by Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), or Frequency Division Multiple Access (FDMA). 13. The method of claim 10, further comprising: Select (S12) at least one indicated resource for monitoring. 14. The method of claim 10, further comprising: The information included in the received message is used to determine (S14) the discontinuous reception DRX period of the wireless device (120, 130). 15. A computer-readable medium storing computer program code that, when executed in a device-to-device (D2D) device (120, 140), causes the wireless device (120) to perform the method according to any one of claims 10-14. 16. A radio node (110, 130) configured to assign resources for device-to-device discovery signaling, the radio node (110, 130) comprising: Transmitter (420); Receiver (430); The processing circuit (410) is configured to cause the radio nodes (110, 130) to: The receiver is used to receive (S1) a set of resources for device-to-device discovery signaling in the corresponding cell or cluster from at least one other radio node (130'). Based on the set of resources received, allocation (S2) is used for resources in device-to-device discovery signaling, and The transmitter is used to transmit to the wireless device controlled by the radio node a message indicating the resources assigned for device-to-device discovery signaling in the cell (C1) or cluster defined by the radio node (110, 130) and at least one other cell (C2) or cluster. 17. The radio node of claim 16, wherein the radio node (110, 130) is a radio network node (130). 18. The radio node according to claim 16 or 17, wherein the radio node (110, 130) is a radio device (110) having authority to control one or more other radio devices (120, 140) in device-to-device discovery communications. 19. A wireless device (120, 140) configured to acquire resources for device-to-device discovery signaling, the wireless device (120) comprising: Transmitter (520); Receiver (530); The processing circuit (510) is configured to cause the wireless device to: The receiver (530) is used to receive from the radio nodes (110, 130) a message indicating resources for device-to-device discovery signaling assigned to a wireless device controlled by the radio nodes (110, 130), wherein the message indicates corresponding resources for device-to-device discovery signaling in each of the cells (C1) or clusters defined by the radio nodes (110, 130) and in other cells (C2) or clusters defined by other radio nodes (130'); and The receiver (530) and/or transmitter (520) are used to utilize the indicated resources for device-to-device discovery signaling.