WO2021028036A1

WO2021028036A1 - Discovery coordination across ue types for v2x/sidelink

Info

Publication number: WO2021028036A1
Application number: PCT/EP2019/071818
Authority: WO
Inventors: Jeroen Wigard; Torsten WILDSCHEK; Nuno Manuel KIILERICH PRATAS
Original assignee: Nokia Technologies Oy
Priority date: 2019-08-14
Filing date: 2019-08-14
Publication date: 2021-02-18

Abstract

In accordance with example embodiments of the invention there is at least a method and apparatus to perform determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and identifying at least one discovery resource pool configured to support the application class of the sidelink application; and using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication. Further, in accordance with example embodiments of the invention there is at least a method and apparatus to perform determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

Description

DISCOVERY COORDINATION ACROSS UE TYPES FOR V2X/SIDELINK

TECHNICAL FIELD:

[0001] The teachings in accordance with the exemplary embodiments of this invention relate generally to improving sidelink/V2V/D2D communications and, more specifically, relate to improving sidelink/V2V/D2D communications targeting 5G and more specifically a discovery phase using these communications.

BACKGROUND:

[0002] This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

[0003] Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:

PC priority class

NC normal class

Prose proximity services

PLMN public land mobile network

PPPP ProSe per packet priority

V2x vehicular to x

D2D device to device

SL sidelink

CBR channel busy rate/ratio

CR channel occupancy ratio

[0004] Cellular network incorporate discovery services which allow computers and other devices to be discovered on a network. With such network discovery, a system will send out messages over the network looking for devices that are discoverable.

[0005] Such discovery services may be used to assist V2X devices to discover and take advantage of safety and non-safety services, which may be broadcasted over one or more channels. The direct discovery services and the direct communication configure a sidelink (sidelink operation).

[0006] In addition, Proximity services (ProSe) have an important function in the

Discovery process. These ProSe services can enable network assisted discovery of wireless communication devices of a network that are in close physical proximity and the facilitation of radio connection establishment and direct communication between these wireless communication devices. For this direct discovery services and the direct communication may configure a sidelink operation with corresponding sidelinks that are provided with discovered wireless communication devices.

[0007] However, with such discovery services there can be issues including interference/capacity issues particularly when there are many devices in proximity of a network device that are providing these corresponding sidelinks.

[0008] Example embodiments of the invention work to improve such discovery services to address at least the issues as mentioned above.

SUMMARY:

[0009] This section contains examples of possible implementations and is not meant to be limiting.

[0010] In one example embodiment of the invention, a method comprises determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and identifying at least one discovery resource pool configured to support the application class of the sidelink application; and using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

[0011] A further example embodiment of the invention is a method comprising the method of the previous paragraph, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class, wherein the identifying is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application, wherein the determining comprises determining a pre-defined number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions, wherein based on listening capabilities of the network device, the identifying the at least one discovery resource pool is performed during predetermined maximum time period provided by the communication and associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period; and wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defmed number of repetitions is received from a network node associated with the communication network.

[0012] In another example embodiment of the invention, an apparatus comprises means for determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and means for identifying at least one discovery resource pool configured to support the application class of the sidelink application; and means for using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

[0013] A further example embodiment of the invention is an apparatus comprising the apparatus of the previous paragraph, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class, wherein the identifying is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application, wherein the determining comprises determining a pre-defined number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions, wherein based on listening capabilities of the network device, the identifying the at least one discovery resource pool is performed during predetermined maximum time period provided by the communication and associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period; and wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defined number of repetitions is received from a network node associated with the communication network.

[0014] In a further example embodiment of the invention, an apparatus comprises one or more processors and one or more memories including computer program code. The one or more memories and the computer program code configured, with the one or more processors, to cause the apparatus to perform at least: determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and identifying at least one discovery resource pool configured to support the application class of the sidelink application; and using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

[0015] Another example embodiment of the invention comprises a computer program comprising code for determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and identifying at least one discovery resource pool configured to support the application class of the sidelink application; and using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

[0016] In another example embodiment of the invention, a method comprises determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

[0017] A further example embodiment of the invention is a method comprising the method of the previous paragraph, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class, wherein the determining is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application, wherein the determining comprises determining a pre-defined number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions; wherein based on listening capabilities of the network device, the indication comprises a predetermined maximum time period provided associated with a sidelink application class, wherein the predetermined maximum time period causes the network device to listen to the at least one discovery resource pool during the predetermined maximum time period provided associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period.; and wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defined number of repetitions is received from a network node associated with the communication network.

[0018] In still another example embodiment of the invention, an apparatus comprises means for determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and means for sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

[0019] A further example embodiment of the invention is an apparatus comprising the apparatus of the previous paragraph, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class, wherein the means for determining is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application, wherein the determining comprises determining a pre-defmed number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defmed number of repetitions; wherein based on listening capabilities of the network device, the indication comprises a predetermined maximum time period provided associated with a sidelink application class, wherein the predetermined maximum time period causes the network device to listen to the at least one discovery resource pool during the predetermined maximum time period provided associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period; and wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defmed number of repetitions is received from a network node associated with the communication network.

[0020] In a further example embodiment of the invention, an apparatus comprises one or more processors and one or more memories including computer program code. The one or more memories and the computer program code configured, with the one or more processors, to cause the apparatus to perform at least: determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

[0021] Another example embodiment of the invention comprises a computer program comprising code for determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0022] The above and other aspects, features, and benefits of various embodiments of the present disclosure will become more fully apparent from the following detailed description with reference to the accompanying drawings, in which like reference signs are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and are not necessarily drawn to scale, in which:

[0023] FIG. 1 shows a simplified reference architecture for ProSe in a non-roaming case;

[0024] FIG. 2 shows discovery request and response for announcing and monitoring user equipment;

[0025] FIG. 3 A shows an example use case in accordance with example embodiments of the invention;

[0026] FIG. 3B shows a Table 1 of CR limit values; [0027] FIG. 4 shows a proposed resource pool partition with user equipment centric load control in accordance with example embodiments of the invention;

[0028] FIG. 5 shows periodic signalling of the network configuration for the access of the sidelink resource pool in accordance with example embodiments of the invention;

[0029] FIG. 6 shows a high level block diagram of various devices used in carrying out various aspects of the invention; and

[0030] FIG. 7A and FIG. 7B each show a method that may be practiced in accordance with example embodiments of the invention.

DETAILED DESCRIPTION:

[0031] In example embodiments of the invention there is proposed at least a method and apparatus to improve sidelink/V2V/D2D communications targeting 5G and more specifically to improve a discovery phase using these communications.

[0032] Example embodiments of the invention relate to sidelink/V2V/D2D communications targeting 5G and more specifically the discovery phase. The scenario considered is a scenario within network coverage, as the interference/capacity issues are solved when there are many devices with corresponding sidelinks around. Such environments are likely to be in network coverage.

[0033] It is noted that at the time of this application there has been introduced for 3GPP standardization operations using LTE sidelinks for D2D communication without much involvement of an eNB or gNB. Here, certain example embodiments of the invention focus on network assisted discovery of users in close proximity to each other.

[0034] FIG. 1 shows a simplified reference architecture for ProSe in a non-roaming case.

In FIG. 1 there is shown the reference architecture for proximity-based services for the non- roammg case. [0035] As shown in FIG. 1 there is a UE 110 and a UE 120 that are connected to a same service providers’ network, to a same PLMN. The UE 110 and the UE 120 each comprise a ProSe application which is used to communicate over links Uu and PC3 with a ProSe Function 107 to EPC 105 via E-UTRAN 100. Then as shown in FIG. 1 the signaling is obtained at the ProSe App Server 109 which feeds back to the ProSe application of each of the UE 110 and the UE 120.

[0036] Most important reference points are the interface between the two devices, PC5 and between each device and the so called Proximity Service (ProSe) Function, PC3. The ProSe Function is one of the most relevant functional entity shown in FIG. 1. The ProSe Function has a very important role in the entire process of Direct Discovery and Direct Communication. It actually provides three sub-functions: Direct Provisioning Function (DPF), Direct Discovery Name Management Function and EPC-level Discovery Function. As the name implies the DPF provisions the UE with all required parameters for Direct Discovery and Direct Communication for this particular network (PFMN). The task for the Direct Discovery Name Management Function is to allocate and process ProSe Application ID’s and ProSe Application Codes that are used for Direct Discovery. This sub-function maintains a table that lists the mapping between the Application Identity (App ID) and Prose Application Code (ProSe App Code). In addition the function generates filter to enable a terminal to know whether an application code is interesting for a given ProSe application running on the device. An additional task for this sub-function is to contact the Home Subscriber Server (HSS) to check if the device is authorized to do Direct Discovery and if so, authorizes the device by synchronizing a ProSe Policy. Finally, it provides the device with integrity parameters to protect discovery messages that are transmitted over the air.

[0037] As indicated herein, it is noted that ProSe Direct Discovery is from a commercial point of view only enabled for the in-coverage scenario and is therefore under full control by the serving network. In other words the network has to authorize a device on a “per UE” basis or a “per UE per application” basis to use Direct Discovery. There are two modes defined how discovery is being used. First, as an announcing terminal (“Here I am!” corresponds to Model A), where a device broadcasts information about itself. In this model a monitoring device is only looking for certain information of interest in its proximity. The announcing device sends out a discovery message that contains a ProSe Application Code. A discovery message is sent at pre defined and network controlled occasions. A monitoring device would monitor these occasions, receive the discovery message and process it. The second model can be described with the phrase “Who is out there?” or “Are you out there?” The ‘Discoverer UE’ sends out a request containing certain information about what it is interested in to discover. The ‘ Disco veree UE’, that receives this message, can respond with some info related to the discoverer’s request. Certain example embodiments of the invention will focus here on model A.

[0038] FIG. 2 shows discovery request and response for announcing and monitoring user equipment. As shown in FIG. 2 there is a UE 110 and a UE 120 which each send discovery requests towards the network, a discovery request 214 and discovery request 224 respectively. The network uses an EPC 205 which incorporates a ProSe Function 207 to determine values associated with transaction ID, ProSe application code, and a validity timer for discovery signals from the UE 110 and the UE 120. Then as shown in FIG. 2 these values are sent from the network towards the UE 110 and UE 120 via the discovery Response 212 and discovery Response 222 respectively.

[0039] An ‘Announcing UE’ (= UE #1 in FIG. 2) uses the Discovery Request procedure to obtain a ProSe Application Code that it uses for its announcements via the Discovery Message over the PC5 interface. The Discovery Request message includes a (new) Transaction ID, the command is set to ‘Announce’, the UE’s identity in form of its IMSI, the ProSe Application Identity (ID) and the Application ID, and both are coming from higher layers. In case the device would like to monitor specific information, the Discovery Request message contains the very same information, with the difference that the command is set to ‘Monitor’ [see UE #2 in Fig. 2] The Application ID is a unique identifier for the application that has triggered the transmission of the Discovery Request message. In both cases, announcing and monitor, the ProSe function contacts the Home Subscriber Server (HSS) to verify that the application, represented by the Application Identity, is authorized for Direct Discovery. If positive, the ProSe function checks if the device is authorized to use the ProSe Application Code either for announcement (UE #1) or for monitoring (UE #2). Afterwards, the network sends a Discovery Response message to the device. For the ‘Announcing UE’ the network returns the ProSe Application Code plus a validity timer for this specific code. For the ‘Monitoring UE’, the Discovery Response message contains one (or more) discovery filter and related filter IDs. After receiving this information UE #1 is configured and ready to announce, where UE #2 is configured and ready to monitor desired information. [0040] The Discovery Message is the information an announcing device transmits in the Discovery Resources, where a monitoring terminal would screen these resources to filter for information of interest. The Discovery Resources are either configured by the network or could be pre-configured in the device. If the device is in idle mode it could use the provided resource pool in SIB Type 19 to announce the discovery message. A device that is already in RRC CONNECTED state may be configured by the eNB via dedicated RRC signaling for autonomous resource selection after authorization has been verified by the eNB. Alternatively, the eNB may provide a dedicated resource allocation to the terminal. A resource allocation is valid until the eNB reconfigures this allocation or the device moves into RRC IDLE state.

[0041] SIB Type 19 provides the information about the radio resource pool where a device is allowed to announce (transmit) or monitor (receive) discovery messages. The resource pool is defined by a discovery period that could be up to 1024 radio frames or 10.24 seconds long. It also defines a bitmap that indicates which subframes could be used for discovery and how often this bitmap is repeated within the discovery period. Additionally a resource configuration for the frequency domain is provided. The explicit number of resource blocks is broadcasted, including a start and end number. That allows the network to organize the uplink bandwidth in clusters.

[0042] In the following example embodiments of the invention there is provided an illustrative use case example based on a V2x scenario, as this use case provides a clear illustration of the problem tackled. Y et, it can be noted that the problem and solutions described herein are applicable to other sidelink use cases where there are a large number of devices or a large variance in the number of devices over time and where some of these need to be discovered faster than others (differentiation is needed). For example, Industrial IoT (e.g. when there are a larger number of sensors with sidelink capabilities, where some are more urgent to be discovered than others) or monitoring and tracking for IoT (e.g. in case of a very high density of containers in a ship or a large number of concatenated wagons in a train).

[0043] FIG. 3A shows an example use case in accordance with example embodiments of the invention. As shown in FIG. 3A there is traffic, such as car and/or truck traffic, and pedestrian 310 at an intersection. As shown in FIG. 3 there can be many devices associated with the traffic and pedestrian 310. These devices can be defined in at least 3 categories: including car, emergency vehicles and pedestrians. Each of these classes have different requirements : it is important that the cars discover the emergency vehicle in time, while it is less critical that a pedestrian discovers another pedestrian. The importance can depend on speed, direction, potential damage, etc. At the same time the number of devices in the example is rather high, so interference and capacity issues may appear, making it unfeasible to always discover the other UEs in time. This is on problem tackled in accordance with example embodiments of this invention.

[0044] It is noted that although in V2x the basic approach is cooperative awareness (meaning that all V2X participants broadcast their location and other basic information all the time to ensure that all other participants are aware of their existence), in the described case whenever there is a high number of devices active in the network then there is the need for a congestion mechanism to ensure that all devices are discoverable to each other.

[0045] Resource pools are essential for low signaling overhead sidelink operation, as these remove the need for network scheduling of each individual sidelink communication link. This is achieved by offloading any control (discovery, synchronization, scheduling) and user plane (data communications) sidelink related interactions to the resource pool and works therefore also outside the coverage of the network.

[0046] A main drawback of this resource pool approach is that the resources are shared by all the sidelink UEs in an uncoordinated manner (i.e. there is contention when accessing the resources in the resource pool) making sidelink communication susceptible to performance degradation when the number of active sidelinks is high enough, i.e. there is congestion. With the increase of the number of UEs capable of sidelink communication (such as vehicle - vehicle, vehicle- pedestrian, vehicle to road side equipment, pedestrian to road side equipment, etc.) it is expected that increasing levels of congestion will be observed in the resource pools reserved for sidelink operation. This congestion will be observed in the form of increased interference, which in turn will cause the drop of the reliability of the sidelink applications, with the highest likelihood of this happening in an environment where reliability of the sidelink is essential (when there are a lot of vehicles, pedestrians, other devices around).

[0047] To cope with the congestion problem there are two general strategies: 1. Increase the number of resources in the resource pool - this approach requires that the network detects this congestion event directly (by measuring the occupation of the resource occupation of the resource pool) or indirectly (via reporting by the UE of the current occupation of the resources, e.g. by measuring the Channel Busy Ratio [TS36.214] and reporting it back to the network). As certain example embodiments of the invention focus on discovery, which is usually done through broadcast, expanding the resources in the common resource pool is challenging as there may be just the time/code/frequency domain to adjust. Time units are typically fixed and have a certain minimum size. Spreading across the code or frequency domain requires UEs to listen to different codes and or frequencies at the same time, which not all of them may be able to do. The main drawback of increasing the number of resources in the sidelink resource pool is that resources are diverted from cellular communication to sidelink communications (unless the resource reuse is being applied) as well the introduction of resource reassignment latency (which includes the detection of the congestion, the resource management algorithm and the informing of all the affected cellular and sidelink UEs of the new resource allocation); However the alternative may be that requirements are not being met, meaning safe operation may not be guaranteed. In accordance with example embodiments of the invention there is proposed a smooth method to optimize resource usage and take into account that not all UEs may be able to listen to all resources simultaneously; and

2. Apply UE centric congestion control - in this approach the UEs measure the occupation of the resource pool resource (e.g. via the Channel Busy Ratio [TS36.214] metric) and then control in a distributed and independent manner their access to the resource pool. The main drawback is the increased access delay, which increases with number of active sidelink UEs, which may lead to the sidelink application requirements not being met, potentially compromising safe operation.

[0048] Unfortunately, due to their drawbacks these two strategies are not suitable to cope with the introduction of sidelink applications with different reliability and latency requirements. Taking as example the use case depicted in FIG. 3 where normal and emergency vehicles are present in an intersection. In this example, the emergency vehicle needs to be discoverable with higher reliability and lower latency, while the discovery requirements for the normal vehicles is more relaxed. In case the intersection is highly congested with vehicles as well as nearby pedestrian UEs then it is easy to imagine that the sidelink resource pools will experience significant congestion.

[0049] A straightforward approach to enable this differentiated access would be to assign dedicated resources (or dedicated resource pools) to the sidelink applications with higher reliability and latency requirements. This approach is not resource efficient as there is no guarantee that these higher reliability applications are always present, and in those cases the dedicated resource pools are not in use. A more resource efficient approach would be to apply strategy 1 in a dynamic manner, i.e. where the dedicated resource pools are activated whenever the higher reliability applications are present. Y et, this approach comes with significant signaling overhead as well as latency as previously described.

[0050] In case a common resource pool is used, then strategy 2 can be applicable but requires differentiated congestion control mechanism for each sidelink application class, which is non-trivial. In accordance with example embodiments of the invention there is proposed such a solution.

[0051] In LTE Rel-14 V2x sidelink communications (over the PSSCH) the radio transmission resources are grouped in transmission pools. Each packet to be transmitted comes from the application layer down to the lower layers associated with a certain priority value (one of eight), called ProSe Per Packet Priority (PPPP). For each of the transmission pools the following parameters are available:

• Channel Busy Rate/Ratio (CBR) - which is the fraction of sub-channels whose S- RSSI exceeds a threshold of -94 dBm; and

• Channel Occupancy Ratio (CR) - which is computed as the number of sub channels used for transmissions in subframes in a given interval.

[0052] FIG. 3B shows a Table of CR Limit values. As shown in FIG. 3B there is a first column with CBR-based PSSCH transmission parameter 410, and underneath it in this column it is showing CBR measured 412. In FIG. 3B there is a second column identifying PPP1=PPP2 420, and underneath it in this column it is showing CR limit 422. In a third column of the table of FIG. 3B there is there is PPP3=PPP5430, and underneath it in this column it is showing CR limit 432. Then lastly in FIG. 3B there is a fourth column with PPP6-PPP8 440, and underneath it in this column it is showing CR limit 442.

[0053] Prior to each transmission, the UE ensures that its CR complies with CR limit by reducing used Resource Blocks (RBs). The CR limit is satisfied for PPPP k, if the following condition is satisfied: the sum of the channel occupancy ratio for PPPP larger than or equal to k is less than or equal to the CRlimit for PPPP k:

Example: If an ITS-S is transmitting packets with priorities PI and P2, where PI is higher priority (P1<P2), then it shall ensure the following limits:

• CRp₂ £ CR limi t_P2 ; and

• CR_pi + CRp₂ £ CR limi t_Pi

[0054] It is up to the implementation to distribute resource usage amongst the packets with priority P 1 and priority P2. For example, allocation of (P 1 packets, P2 packets) to resources (CRlimitpi - CRlimitp2, CRlimitp2) or generally (CRlimitpi - x, x), where x <= CRlimitp2, are all feasible.

[0055] The PPPP mechanism can be extended to discovery procedure (i.e. applied to the

PSDCH), but the main drawback is the latency that it introduces to all the classes (or PPPPs). As an illustrative example, consider that the resource pool used for discovery is experiencing a CBR above 0.8 and that there two types of discovery applications active one with PPPP 1 another with PPPP8. In these conditions, the PPPP1 application would only be able to start discovery 2% of the time while the PPPP8 0.2% of the time. This would be the case until the CBR in the discovery resource pool would go below 0.65.

[0056] In accordance with example embodiments of the invention there is proposed an alternative approach that does not introduce the PPPP latency penalty to the discovery class with higher priority. [0057] Before describing the example embodiments of the invention in detail, reference is made to FIG. 6 for illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing the example embodiments of this invention.

[0058] Turning to FIG. 6, this figure shows a block diagram of one possible and non limiting exemplary system in which the exemplary embodiments may be practiced. In FIG. 6, a user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless, typically mobile device that can access a wireless network. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 may include a SideLink Module, comprising one of or both parts 140-1 and/or 140-2, which may be implemented in a number of ways.

[0059] This SideLink Module is an optional module and can be customized with software and/or processors to perform example embodiments of the invention as disclosed herein. These SideLink Modules parts can include processor configurations that can be implemented to perform example embodiments of the invention as disclosed herein. The SideLink Module may be implemented in hardware as SideLink Module 140-1, such as being implemented as part of the one or more processors 120. The SideLink Module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the SideLink Module may be implemented as SideLink Module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. In addition, the SideLink Modules as shown in LIG. 6 are optional and their operations can be performed by other devices of the UE 110 as shown in LIG. 6. Lor instance, the one or more memories 125 and the computer program code 123 may be configured, with the one or more processors 120, to cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with radio access network or Network Node 170 via a wireless link 111. [0060] The Network Node 170 may be a base station that provides access by wireless devices such as the UE 110 to the wireless network 100. For example, the Network Node 170 may be a node (e.g. a base station) in a NR/5G network such as a gNB (a node that provides NR user plane and control protocol terminations towards the UE 110) or an ng-eNB (a node providing E-UTRA user plane and control plane protocol terminations towards the UE 110, and connected via anNG interface to the core network (i.e. 5G Core (5GC)). The Network Node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The Network Node 170 a SideLink Module, comprising one of or both parts 150-1 and/or 150-2.

[0061] These SideLink Module parts can include processor configurations that can be implemented to perform example embodiments of the invention as disclosed herein, which may be implemented in a number of ways. The SideLink Module may be implemented in hardware as SideLink Module 150-1, such as being implemented as part of the one or more processors 152. The SideLink Module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the SideLink Module may be implemented as SideLink Module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. In addition, the SideLink Modules as shown in FIG. 6 are optional and their operations can be performed by other devices of the Network Node 170 as shown in FIG. 6. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, to cause the Network Node 170 to perform one or more of the operations as described herein. The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. T wo or more RAN nodes 170 communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, e.g., an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0062] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195, with the other elements of the Network Node 170 being physically in a different location from the RRH, and the one or more buses 157 could be implemented in part as fiber optic cable to connect the other elements of the Network Node 170 to the RRH 195.

[0063] The wireless network 100 may include a network control element or elements

NCE 190 that may include core network functionality, and which provides connectivity via a link or links with a further network, such as a telephone network and/or a data communications network (e.g., the Internet). Such core network functionality for 5G may include access and mobility management function(s) (AMF(s)) and/or user plane functions (UPF(s)) and/or session management function(s) (SMF(s)). Such core network functionality for FTE may include MME (Mobility Management Entity)/SGW (Serving Gateway) functionality. These are merely exemplary functions that may be supported by the NCE 190, and note that both 5G and LTE functions might be supported. The Network Node 170 is coupled via a link 131 to a network control element such as the NCE 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The NCE 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the NCE 190 to perform one or more operations.

[0064] In accordance with example embodiments of the invention there is proposed a UE centric congestion control mechanism that enables the discovery operation of sidelink applications with different reliability requirements, with minimal support from the network.

[0065] One general concept of the proposed scheme is depicted in FIG. 4 where two groups of applications coexist and there are two resource pools, which can be used to send their discovery signal. Note that the number of resources pools can be larger than two, but example embodiments of the invention can use two for simplicity.

[0066] As shown in FIG. 4 there is shown several resource pools of Resource pool 1 and

Resource pool 2. As shown in FIG. 4 these resource pools comprise Normal class 410 and/or Priority class 420 identifiers. It is noted that as shown in FIG. 4 these classes of the resource pools can change over time t 450. [0067] One application has higher reliability requirements and is denoted as “Priority class” (PC), while the other application has lower reliability requirements and is denoted as “Normal class” (NC). The number of classes can be larger than two, but for simplicity example embodiments of the invention limit the number to two here. The PC has priority access for the transmission of its discovery signals to resource pool 1, while NC can use resource pool 2 for transmission of its discovery signals but can also use resource pool 1 whenever the load (caused by UEs associated with PC and NC) is lower than a certain threshold. The main difference between the PC and NC (beyond the different reliability requirements) is that the PC is not always present (e.g. associated with an emergency vehicle) and when that is the case either the full resources of both resource pools should be available for the NC or NC can be limited to use resource pool 1 only and resource pool2 can be used for different purposes.

[0068] Whenever the PC becomes active (as it is the case at t3 in FIG. 4 or the UEs belonging to PC start occupying more than CBR threshold % of the resources in resource pool 1 , the UEs associated with NC move their discovery signals to the resource pool 2. As shown in the FIG. 4 at t3 and U, the change of the NC UEs from resource pool 1 to resource pool 2 is not instantaneous, as these have first to detect that the PC UEs are now using the resource pool 1. In practice the detection can be done by each NC UE detecting that the discovery signals of the NC plus the newly arrived PC UE ’ s are occupying more than a certain CBR threshold in the resource pool 1 (i.e. by measuring the CBR). This CBR threshold can be set very low so that the NC UEs vacate the resource pool 1 immediately and do not impact the PC UEs discovery performance. Alternatively, the NC UEs can detect if there are any PC discovery signals present (or if the CBR due to these is above a certain threshold) and then vacate resource pool 1.

[0069] When the NC plus the PC associated discovery signals are filling less than a certain percentage in the resource pool 1 (as is the case at ts) the NC UEs detect this event and then extend again their access to the resource pool 1 and may leave resource pool 2, which then can be used for other purposes. This procedure is done at each UE independently, but the thresholds used by the UEs to decide when to join or leave a sub-pool are provided by the network. Note that as certain example embodiments of the invention are focusing on discovery and as such all UEs need to listen to both resource pools, so the NC UE listen to the resource pool 1 to discover the UEs there, whereas they also listen to resource pool 2 to detect other NC UEs. In order to ensure that the different UEs can discover each other within the requirements, the following needs to be in place:

• PC UE sends discovery signals rather often on resource pool 1 ;

• NC UE sends discovery signals on resource pool 1 or resource pool 2 and can do this with a lower frequency as they have lower requirements;

[0070] Furthermore, in case the UEs are not able to listen to all the resource pools (e.g. in case these resource pools are at different carriers and the UEs cannot operate simultaneously in all of them), then:

• PC UE listen to resource pool 1 a certain percentage of the time and to resource pool 2 the remaining time. The time allocated to resource pool 1 will likely be larger in order to detect other PC UEs; and

• NC UE listen to resource pool 1 a certain percentage of the time and to resource pool 2 the remaining time. The time allocated to sub-pool 1 will likely be larger in order to detect PC UEs.

[0071] Note that the load of resource pool 1 and 2 is low enough, all UEs can transmit their discovery signals in resource pool 1 , thereby avoiding the switching between the resource pools.

[0072] Elements in accordance with example embodiments of this invention that are seen to need to be protected include the following:

• Resources are partitioned into resource pools, where each resource pool has associated a maximum activity threshold (i.e. a Channel Busy Ratio) that when crossed blocks a given sidelink class or given sidelink classes from transmitting discovery signals in it;

• In one implementation all sidelink application classes are able to access resource pools as long as the activity level in those resources is low enough, while in another implementation the resource pools are decreased when the activity levels are below a certain second activity threshold;

• Each sidelink application reliability class has priority access for its discovery signals over at least one resource pool, which is enforced by the application not having a maximum activity threshold associated with it in that same sub-resource pool;

• Increased access reliability by allowing each application to perform a predefined number of randomized repetitions of the discovery signal (i.e. allowing each UE to perform K non-contiguous and randomized repetitions) in their associated sub-resource pool. This mechanism increases the reliability both by the additional randomized repetitions (a process that allows to randomize the interference) as well as by preventing the access of other applications when the activity level in the resources pool becomes high enough (i.e. the other applications are blocked access to the resource sub-pool). The latter due to the additional repetitions increasing the channel occupancy ratio, which in case of high enough congestion leads to the UEs that access the resources in an opportunistic manner to stop accessing (temporarily) the sub-pool;

• Every sidelink application class listening percentages are given to the UEs which do not have the capability of listening to different resource pools simultaneously indicating the amount of time to listen to the different pools; and

• Network controlled access rules to each resource sub-pool, such as number of allowed randomized repetitions per access class, the activity thresholds per resource pool, the resource allocation for the resource pool, the division into resource pools and the listening percentages per application class.

[0073] In the following sub-sections, there is introduced in details the elements of the proposed solution in accordance with example embodiments of the invention as well as the behavior of the sidelink UEs in regard to their transmission.

[0074] Resource pools, decision thresholds, listening thresholds and RRC signaling [0075] The resource pools and their partitioning is controlled by the network via dedicated signaling that is broadcasted periodically. Whenever the UEs are not in coverage then they revert to default configuration which can still include the proposed functionality.

[0076] The RRC signaling should include the following elements:

• Resource allocation for the sidelink resource pools: o resource pool partition - Includes the partition in resource pools or identification which resource pool corresponds to a given application; o resource pool occupancy threshold - Includes the resource occupation threshold after which, the sidelink applications with non-priority channel access need to leave the resource pool (or when they can join the resource pool, i.e. if the resource occupation is below the defined threshold);

• Configuration of the sidelink applications reliable access scheme: o Id of the sidelink application class - this identifies the application class, which translates to specific latency and reliability requirements; o Number of allowed randomized repetitions in own resource pool (K) - this controls how many randomized repetitions (i.e. non-contiguous repetitions randomized across the resources of the resource pool in order to randomize the experienced interference) the UEs associated with application are able to do. K>1 only when the application class has higher reliability target; o Backoff factor in own resource pool - this controls how the UE should back-off when operating in its own sub-pool, e.g. exponential back-off to apply. The backoff can be applied by means of preventing the UE from accessing the pool by some slots/frames; o Backoff factor in other resource-pools - this controls how the UE should back-off when operating in other sub-pools, e.g. exponential back-off to apply. The backoff can be applied by means of preventing the UE from accessing the pool by some slots/frames; o Listening thresholds - indicating which percentage of time needs to be listened to the different resource pools, if more than a single resource pool exists. This is necessary for the UEs that are not able to listen to all the pools simultaneously.

[0077] This information is shared with all UEs in the network periodically via system information, as depicted in FIG. 5. As shown in FIG. 5 there is from a gNB 570 over periodic signalling a transmission of a SIB x 530 and SIB x 540 for an application 1 510 of UE i and UE i+m, and for an application 2 520 of UE j and UE j+n.

[0078] Behavior of a UE when accessing own resource pool

[0079] The behavior of the UE when accessing its own resource pool is as follows:

1. Receive sidelink resource pool configuration from the network;

2. UE accesses its own resource pool for transmission of discovery signals: a. If the UE belongs to a high reliability class, the UE accesses with the configured K randomized repetitions; b. If the resource occupancy is too high (i.e. even with repetitions the UE is not able to achieve the desired reliability due to congestion and the associated interference): i. If it is the first time accessing the resource pool (e.g. first slot or frame), do nothing and wait for the next slot or frame; and ii. Otherwise, back-off according with the backoff factor. [0080] Behavior of a UE when accessing other resource pool

[0081] The behavior of the UE when accessing other resource pool is as follows:

1. Receive sidelink resource pool configuration from the network;

2. Monitor other resource pools: a. If the resource occupancy of the monitored resource pool is below the configured occupancy threshold, then proceed with access in the resource pool step 3; b. If the resource occupancy of the monitored resource pool is above the configured occupancy threshold, then do not access resource pool in upcoming slot/frame or move to a next resource pool if available;

3. UE accesses other resource pool for transmission of discovery signals: a. If the UE belongs to a high reliability class, such as relative to this other resource pool, the UE accesses with the configured K randomized repetitions.

[0082] FIG. 7A illustrates operations which may be performed by a network device such as, but not limited to, a network device such as the UE 110 as in FIG. 6. As shown in step 710 of FIG. 7A determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication. As shown in step 720 of FIG. 7A there is identifying at least one discovery resource pool configured to support the application class of the sidelink application. Then as shown in step 730 of FIG. 7A there is using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

[0083] In accordance with the example embodiments as described in the paragraph above, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class.

[0084] In accordance with the example embodiments as described in the paragraphs above, wherein the identifying is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool.

[0085] In accordance with the example embodiments as described in the paragraphs above, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication.

[0086] In accordance with the example embodiments as described in the paragraphs above, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool.

[0087] In accordance with the example embodiments as described in the paragraphs above, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal.

[0088] In accordance with the example embodiments as described in the paragraphs above, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased.

[0089] In accordance with the example embodiments as described in the paragraphs above, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application.

[0090] In accordance with the example embodiments as described in the paragraphs above, wherein the determining comprises determining a pre-defmed number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application.

[0091] In accordance with the example embodiments as described in the paragraphs above, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defmed number of repetitions.

[0092] In accordance with the example embodiments as described in the paragraphs above, wherein based on listening capabilities of the network device, the identifying the at least one discovery resource pool is performed during predetermined maximum time period provided by the communication and associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period;

[0093] In accordance with the example embodiments as described in the paragraphs above, wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defmed number of repetitions is received from a network node associated with the communication network.

[0094] In accordance with an example embodiment of the invention as described above there is an apparatus comprising: means for determining (e.g., one or more transceivers 130, Memory(ies) 125 storing Computer Program Code 123 executed by Processors 120 and/or SideLink Module 140-1 and/or SideLink Module 140-2 as in FIG. 6), by a network device (e.g., UE 110 as in FIG. 6) of a communication network (e.g., Wireless Network 100 as in FIG. 6), to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; means for identifying (e.g., one or more transceivers 130, Memory(ies) 125 storing Computer Program Code 123 executed by Processors 120 and/or SideLink Module 140-1 and/or SideLink Module 140-2 as in FIG. 6) at least one discovery resource pool configured to support the application class of the sidelink application; and means for using (e.g., one or more transceivers 130, Memory(ies) 125 storing Computer Program Code 123 executed by Processors 120 and/or SideLink Module 140-1 and/or SideLink Module 140-2 as in FIG. 6) the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

[0095] In the example aspect of the invention according to the paragraph above, wherein at least the means for determining, identifying, and sending as disclosed above comprises a non- transitory computer readable medium [Memory(ies) 125 as in FIG. 6] encoded with a computer program [Computer Program Code 123 as in FIG. 6] executable by at least one processor [Processors 120 and/or SideLink Module 140-1 and/or SideLink Module 140-2 as in FIG. 6]

[0096] FIG. 7B illustrates operations which may be performed by a network device such as, but not limited to, a network node such as the Network Node 170 as in FIG. 6. As shown in step 750 of FIG. 7B there is determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device. Then as shown in step 760 of FIG. 7B there is sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

[0097] In accordance with the example embodiments as described in the paragraph above, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class.

[0098] In accordance with the example embodiments as described in the paragraphs above, wherein the determining is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool.

[0099] In accordance with the example embodiments as described in the paragraphs above, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication.

[00100] In accordance with the example embodiments as described in the paragraphs above, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool.

[00101] In accordance with the example embodiments as described in the paragraphs above, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal.

[00102] In accordance with the example embodiments as described in the paragraphs above, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased.

[00103] In accordance with the example embodiments as described in the paragraphs above, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application.

[00104] In accordance with the example embodiments as described in the paragraphs above, wherein the determining comprises determining a pre-defmed number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application.

[00105] In accordance with the example embodiments as described in the paragraphs above, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions.

[00106] In accordance with the example embodiments as described in the paragraphs above, wherein based on listening capabilities of the network device, the indication comprises a predetermined maximum time period provided associated with a sidelink application class, wherein the predetermined maximum time period causes the network device to listen to the at least one discovery resource pool during the predetermined maximum time period provided associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period.

[00107] In accordance with the example embodiments as described in the paragraphs above, wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defined number of repetitions is received from a network node associated with the communication network.

[00108] In accordance with an example embodiment of the invention as described above there is an apparatus comprising: means for determining (e.g., one or more transceivers 160, Memory(ies) 155 storing Computer Program Code 153 executed by Processors 152 and/or SideLink Module 150-1 and/or SideLink Module 150-2 as in FIG. 6), by a network node (e.g., network node 170 as in FIG. 6) of a communication network (wireless network 100 as in FIG. 6), at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device (e.g., UE 110 as in FIG. 6) for communication of a discovery signal by the network device. Then means for sending (e.g., one or more transceivers 160, Memory(ies) 155 storing Computer Program Code 153 executed by Processors 152 and/or SideLink Module 150-1 and/or SideLink Module 150-2 as in FIG. 6) towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

[00109] In the example aspect of the invention according to the paragraph above, wherein at least the means for determining and means for sending as disclosed above comprises a non- transitory computer readable medium [Memory(ies) 155 as in FIG. 6] encoded with a computer program [Computer Program Code 153 as in FIG. 6] executable by at least one processor [Processors 152 and/or SideLink Module 150-1 and/or SideLink Module 150-2 as in FIG. 6]

[00110] The word "exemplary" as may be used herein is intended to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

[00111] The foregoing description has provided by way of exemplary and non- limiting examples a full and informative description of the best method and apparatus presently contemplated by the inventors for carrying out the invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention.

[00112] It should be noted that the terms "connected," "coupled," or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and/or printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as several non-limiting and non-exhaustive examples. [00113] Furthermore, some of the features of the preferred embodiments of this invention could be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles of the invention, and not in limitation thereof.

Claims

CLAIMS What is claimed is:

1. A method, comprising: determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and identifying at least one discovery resource pool configured to support the application class of the sidelink application; and using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

2. The method of claim 1, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class.

3. The method of claim 2, wherein the identifying is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool.

4. The method of claim 3, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication.

5. The method of claim 3, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool.

6. The method of claim 5, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal.

7. The method of claim 5, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased.

8. The method of claim 1, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application.

9. The method of claim 1, wherein the determining comprises determining a pre-defmed number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application.

10. The method according to any one of the preceding claims, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defmed number of repetitions.

11. The method according to any one of the preceding claims, wherein based on listening capabilities of the network device, the identifying the at least one discovery resource pool is performed during predetermined maximum time period provided by the communication and associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period.

12. An apparatus, comprising: means for determining, by a network device of a communication network, to communicate a discovery signal using a sidelink application of at least one sidelink application of the network device, wherein each sidelink application of the at least one sidelink application is using an application class for discovery signal communication; and means for identifying at least one discovery resource pool configured to support the application class of the sidelink application; and means for using the identified at least one discovery resource pool configured to support the application class for the discovery signal communication.

13. The apparatus of claim 12, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class.

14. The apparatus of claim 13, wherein the identifying is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool.

15. The apparatus of claim 13, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication.

16. The apparatus of claim 14, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool.

17. The apparatus of claim 15, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal.

18. The apparatus of claim 15, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased.

19. The apparatus of claim 12, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application.

20. The apparatus of claim 12, wherein the determining comprises determining a pre defined number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application.

21. The apparatus according to any one of the preceding claims, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions.

22. The apparatus according to any one of the preceding claims, wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defined number of repetitions is received from a network node associated with the communication network.

23. A method, comprising: determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

24. The method of claim 23, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class.

25. The method of claim 24, wherein the determining is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool.

26. The method of claim 24, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication.

27. The method of claim 25, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool.

28. The method of claim 27, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal.

29. The method of claim 27, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased.

30. The method of claim 23, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application.

31. The method of claim 23, wherein the determining comprises determining a pre defined number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application.

32. The method according to any one of the preceding claims, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions.

33. The method according to any one of the preceding claims, wherein based on listening capabilities of the network device, the indication comprises a predetermined maximum time period provided associated with a sidelink application class, wherein the predetermined maximum time period causes the network device to listen to the at least one discovery resource pool during the predetermined maximum time period provided associated with a sidelink application class, and wherein the listening is performed for a first discovery resource pool and then another discovery resource pool of the at least one discovery resource pool based on an expiration of the predetermined maximum time period.

34. An apparatus, comprising: means for determining, by a network node of a communication network, at least one discovery resource pool for the communication network, wherein the at least one discovery resource pool is configured to support an application class of a sidelink application of a network device for communication of a discovery signal by the network device; and means for sending towards the network device an indication of the at least one discovery resource pool of the communication network to cause the sidelink application of the network device to communicate a discovery signal using the at least one discovery resource pool.

35. The apparatus of claim 34, wherein the application class comprises one of a normal application class or a priority application class, and wherein the at least one discovery resource pool configured to support the application class is given priority access for communicating the discovery signal over a sidelink resource pool with the normal application class.

36. The apparatus of claim 35, wherein the means for determining is using a partition or identification for each resource pool of the at least one resource pool indicating an application class that is supported by the resource pool.

37. The apparatus of claim 35, wherein the sidelink application uses the priority application class for priority access, and wherein the partition or identification of the identified at least one discovery resource pool indicates that identified at least one discovery resource pool supports the priority application class of the application for the discovery signal communication.

38. The apparatus of claim 35, wherein at least one activity threshold is associated with the partition or identification based on the application class for each discovery resource pool of the at least one discovery resource pool.

39. The apparatus of claim 37, wherein based on the at least one activity threshold not being exceeded for a discovery resource pool of the at least one discovery resource pool, the discovery resource pool transmits the discovery signal, or wherein based on at least one activity threshold being exceeded for the discovery resource pool, one of: the discovery resource pool is not allowing transmitting of the discovery signal, or if the network device belongs to a high reliability class, the network device the discovery resource pool transmits the discovery signal.

40. The apparatus of claim 37, wherein based an activity threshold of the at least one activity threshold being exceeded for the discovery resource pool a number of discovery signals that is allowed to be processed using that discovery resource pool is decreased.

41. The apparatus of claim 34, wherein the signaling comprises an indication of an application class of the at least one application, and wherein the application class translates to quality of service requirements of the at least one application.

42. The apparatus of claim 34, wherein the determining comprises determining a pre defined number of repetitions for using the discovery resource pool for the sidelink signaling to process the discover signal associated with the at least one application.

43. The apparatus according to any one of the preceding claims, wherein the determining comprises determining to use the at least one discovery resource pool for the communicating based on at least one of the at least one activity threshold, the indication of an application class of the at least one application, or the pre-defined number of repetitions.

44. The apparatus according to any one of the preceding claims, wherein an indication of at least one of the at least one activity threshold, the application class of the at least one application, or the pre-defined number of repetitions is received from a network node associated with the communication network.

45. A communication system comprising the apparatus in accordance with any one of the claims 12 to 22 and the apparatus in accordance with any one of the claims 34 to 44.

46. A computer program comprising program code for executing the method according to any of claims 1 to 11 or 23 to 33.

47. The computer program according to claim 46, wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.