Devices and methods for DRX management of a group of UES in a mobile network

Abstract

A base station (110) for communication with a group of user equipments, UEs, (120a-n) is disclosed. The base station (110) is configured to transmit a discontinuous reception, DRX, schedule configuration message to the group of UEs (120a-n). The DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs (120a-n). Moreover, the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE (120a-n) of the group of UEs (120a-n). Thus, the base station (110) may efficiently manage the individual as well as the group DRX behaviour of the group of UEs (120a- n) with a single configuration message allowing to substantially reduce signalling overhead.

Description

[0001] DEVICES AND METHODS FOR DRX MANAGEMENT OF A GROUP OF UES IN A MOBILE NETWORK

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communication. More specifically, the present disclosure relates to devices and methods for DRX management of a group of user equipments, UEs, in a mobile network.

[0004] BACKGROUND

[0005] In an effort to save power, wireless user equipments, UEs, can activate discontinuous reception as described, for instance, in Liang, Jia-Ming, et al. "Energy -efficient DRX scheduling for multicast transmissions in 3 GPP LTE- Advanced wireless networks" 2013 IEEE Wireless Communications and Networking Conference (WCNC), IEEE, 2013. DRX operates in cyclical periods, where during a cycle in a small time slot with defined duration the UE is active and available for receiving data, while in the rest of the duration of the cycle the UE turns off its communication components. For supporting DRX the UE is configured to quickly and efficiently iterate between switching on / off its communication components within some period, now commonly found on most UEs. While the UE can decide to wake up and disrupt the inactivity of the communication components to send data, it is not possible for the UE to be disrupted and awaken by receiving data when its communication components are offline. If another entity needs to wake up the UE, it can disrupt the DRX cycle by sending a wake-up signal in the slot where the UE is listening. To guarantee reachability, the configuration of the DRX mechanism needs to be communicated and coordinated with communication partners, such as a base station, BS, as well as other UEs from which data might be received.

[0006] In addition to mobile phones UEs are more and more implemented as other types of devices or embedded as components thereof, such as vehicles, robots, appliances, sensors, tools, and the like. The role of embedded UEs is to serve multiple communication purposes, among which: transmit / receive unicast data to / from other UEs or a BS in the mobile network, transmit / receive multicast data to / from other UEs or a BS in the mobile network, transmit / receive sensing signals from other UEs, a BS or other devices in the environment. Depending on their communication purpose, groups of UEs may be formed with the purpose of contextualizing their network behavior, e.g. to collaborate to accomplish some tasks, consume the same data stream from some source, communicate information between themselves, stream sensed data from one UE to another. For instance, vehicular UEs may be grouped to identify the UEs that share or receive sensing information of the traffic environment, transmit / receive / exchange messages, consume or stream audio / visual or audiovisual content, receive teleoperation instructions with varying levels of control over the vehicle, and the like.

[0007] When the UEs do not exploit their communication components for the aforementioned or other purposes, they can use DRX and improve their energy efficiency. The saved energy can be significant for small scale and battery powered systems such as robots, sensors, remote controllers, and the like. For many of the aforementioned embedded UEs the communication is of relevance to the security and safety, where information latency and age of information become crucial. DRX imposes risks of increasing latency and age of information and thus harm the operation of UEs. For instance, for vehicular UEs the small DRX communication time slot may not be sufficient if their channel conditions change due to their mobility. Due to the aforementioned and other reasons, DRX usage at such embedded UEs is reduced to avoid conflicts with data service streams, thus reducing the energy efficiency performance of the UEs.

[0008] Since the UEs often need to support multiple services simultaneously, the DRX configurations need to be optimized and reflect the needs of the services. For instance, some non-priority information sharing service regarding the surroundings may reach some second UE from the source first UE. If the second UE is closer to a third UE, and the application on the second UE considers the piece of information critical for the third UE, it sends a critical message to it through a high priority service. The non-priority service and the high priority service may be linked, and the DRX cycle slots timing needs to be allocated with this in mind. Such a multi-service application is, for instance, sensing. The sensing process goes through three phases: collection, processing, reporting where each of the phases may require a different service if the phases are distributed among a group of UEs. A UE might perform sensing on its own (mono-static sensing) and send the report to a concerned device. A UE might also collect a partial reflection of an active wireless sensing pattern from one or more base stations or other UEs and send the information of the partial reflection to be processed at another entity (multi-static sensing.) The key drawback of using DRX in sensing is that it reduces the reachability of UEs relevant to the sensing process.

[0009] This type of DRX lacks support for multi-stream applications or collaborative services, such as sensing. Thus, current DRX implementations are turned off for applications such as sensing. To enable sensing and DRX it is key for sensed information that reaches the destination to be as fresh as possible and, thus, have the lowest age of information as possible. Additionally, current solutions do not allow for dynamic DRX re-configurations when the propagational environments of mobile UEs are changing. This is due to the fact that each DRX configuration requires a separate message and UEs changing DRX configurations on its own may result in unexpected unreachability .

[0010] SUMMARY

[0011] It is an objective of the present disclosure to provide improved devices and methods for DRX management of a group of UEs in a mobile network.

[0012] The foregoing and other objectives are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

[0013] According to a first aspect a base station for communication with a group of user equipments, UEs, is provided, wherein each UE is configured to operate according to a discontinuous reception, DRX, schedule.

[0014] The base station according to the first aspect is configured to transmit a discontinuous reception, DRX, schedule configuration message to the group of UEs. The DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs. The DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE of the group of UEs. Thus, the base station according to the first aspect may efficiently manage the individual as well as the group DRX behaviour of a group of UEs with a single configuration message allowing to substantially reduce signalling overhead.

[0015] In a further possible implementation form, each UE DRX schedule of the plurality of UE DRX schedules is readable by each UE of the group of UEs. In other words, the base station is configured such that the UE DRX schedule for each UE is readable by all the other UEs of the group of UEs. Thus, eachUE can communicate directly or via the BS with another UE of the group of UEs without incurring additional delays for discovering the active times of a respective UE.

[0016] In a further possible implementation form, the DRX schedule configuration message is further indicative of a plurality of UE identifiers, wherein each UE identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a UE of the group of UEs identified by the UE identifier. Hence, each UE obtains the capability to identify its own DRX schedule as well as the DRX schedule of all the other UEs in the group of UEs. In a further possible implementation form, the DRX schedule configuration message is further indicative of a plurality of service identifiers and wherein each service identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a service of a plurality of services of a UE of the group of UEs identified by the service identifier. Hence, the UE may increase its energy efficiency by enabling / disabling special services through their appropriate DRX schedule. It also allows for the simultaneous creation of multiple DRX schedules for multiple services, without the need of additional signalling.

[0017] In a further possible implementation form, the plurality of services comprises a multicast service, a unicast service, and / or a sensing service.

[0018] In a further possible implementation form, the base station is configured to generate the GROUP DRX schedule and / or the plurality of UE DRX schedules based on timing requirements of the plurality of services. Thus, the UE or the BS obtain the capability to optimize multi-service information streams that comprise of any unicast, multicast or sensing service.

[0019] In a further possible implementation form, each UE DRX schedule defines a UE DRX cycle comprising a plurality of UE DRX cycle time slots.

[0020] In a further possible implementation form, the DRX schedule configuration message is further indicative of one or more spatial regions, wherein the GROUP DRX schedule and / or the plurality of UE DRX schedules are valid only for the one or more spatial regions, i.e. when a respective UE is located within the one or more spatial regions. Thus, the UE may increase its energy efficiency by enabling / disabling special services through their appropriate DRX schedule. It also allows for the simultaneous creation of multiple DRX schedules for multiple services, without the need of additional signalling.

[0021] In a further possible implementation form, the base station is configured to obtain a path plan for each of the plurality of UEs and to generate the GROUP DRX schedule and / or the plurality of UE DRX schedules based on the plurality of path plans of the plurality of UEs.

[0022] In a further possible implementation form, the base station is further configured to transmit a sensing signal or to trigger transmission of a sensing signal, wherein one or more of the plurality of UEs are configured, based on the GROUP DRX schedule and / or the plurality of UE DRX schedules, to receive the sensing signal and / or a signal based on the sensing signal during the transmission of the sensing signal.

[0023] According to a second aspect a method for communication between a base station and a group of user equipments, UEs, is provided. The method according to the second aspect comprises the step of transmitting a discontinuous reception, DRX, schedule configuration message to the group of UEs, wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs and wherein the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE of the group of UEs.

[0024] The method according to the second aspect can be performed by the base station according to the first aspect. Thus, further features of the method according to the second aspect result directly from the functionality of the base station according to the first aspect as well as its different implementation forms described above and below.

[0025] According to a third aspect a user equipment, UE, for communication with a base station is provided. The UE, which may belong to a group of UEs and be configured to communicate with one or more further UEs of the group of UEs, is configured to operate according to a discontinuous reception, DRX, schedule. The UE according to the third aspect is configured to receive a discontinuous reception, DRX, schedule configuration message from the base station. The DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs, including the UE. The DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE of the group of UEs.

[0026] In a further possible implementation form, the UE is configured to read, i.e. extract and interpret each of the plurality of UE DRX schedules of the DRX schedule configuration message.

[0027] In a further possible implementation form, the UE is configured to schedule, based on the plurality of UE DRX schedules, a transmission to one or more further UEs of the group of UEs.

[0028] In a further possible implementation form, the DRX schedule configuration message is further indicative of a plurality of UE identifiers, wherein each UE identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a UE of the group of UEs identified by the UE identifier.

[0029] In a further possible implementation form, the DRX schedule configuration message is further indicative of a plurality of service identifiers, wherein each service identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a service of a plurality of services of a UE of the group of UEs identified by the service identifier.

[0030] In a further possible implementation form, the plurality of services comprises a multicast service, a unicast service, and / or a sensing service.

[0031] In a further possible implementation form, each UE DRX schedule defines a UE DRX cycle comprising a plurality of UE DRX cycle time slots.

[0032] In a further possible implementation form, the DRX schedule configuration message is further indicative of one or more spatial regions and wherein the GROUP DRX schedule and / or the plurality of UE DRX schedules are valid only for the one or more spatial regions, i.e. when a respective UE is located within the one or more spatial regions.

[0033] According to a fourth aspect a method for communication between a user equipment, UE, of a group of UEs and a base station is provided. The method according to the fourth aspect comprises receiving a discontinuous reception, DRX, schedule configuration message from the base station. The DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs, including the UE. The DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE of the group of UEs.

[0034] The method according to the fourth aspect can be performed by the UE according to the third aspect. Thus, further features of the method according to the fourth aspect result directly from the functionality of the UE according to the third aspect as well as its different implementation forms described above and below.

[0035] According to a fifth aspect, a computer program product is provided, comprising a computer-readable storage medium for storing program code which causes a computer or a processor to perform the method according to the second aspect, or the method according to the fourth aspect, when the program code is executed by the computer or the processor. Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the following, embodiments of the present disclosure are described in more detail with reference to the attached figures and drawings, in which:

[0038] Fig. 1 shows a schematic diagram illustrating a communication system including a base station according to an embodiment in communication with a group of UEs according to an embodiment;

[0039] Fig. 2 shows a schematic diagram illustrating the sending of a DRX schedule configuration message from a base station to a group of UEs according to an embodiment;

[0040] Fig. 3 shows a schematic diagram illustrating several cycles of an exemplary GROUP DRX schedule and two exemplary UE DRX schedules for a group of UEs according to an embodiment;

[0041] Fig. 4 shows a schematic diagram illustrating the sending of a DRX schedule configuration message from a base station according to an embodiment to a group of UEs according to an embodiment for an exemplary multi-static sensing application;

[0042] Fig. 5 shows a schematic diagram illustrating several cycles of exemplary DRX schedules for a group of UEs according to an embodiment for a multi-static sensing application with a multicast report;

[0043] Fig. 6 shows a schematic diagram illustrating the sending of a DRX schedule configuration message from a base station according to an embodiment to a group of UEs according to an embodiment for a further exemplary multi-static sensing application;

[0044] Fig. 7 shows a flow diagram illustrating a method of operating a base station according to an embodiment; and

[0045] Fig. 8 shows a flow diagram illustrating a method of operating a user equipment according to an embodiment.

[0046] In the following, identical reference signs refer to identical or at least functionally equivalent features.

[0047] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] In the following description, reference is made to the accompanying figures, which form part of the disclosure, and which show, by way of illustration, specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present disclosure may be used. It is understood that embodiments of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0049] For instance, it is to be understood that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a specific apparatus is described based on one or a plurality of units, e.g. functional units, a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and / or aspects described herein may be combined with each other, unless specifically noted otherwise.

[0050] Figure 1 shows a schematic diagram illustrating a communication system 100 including a base station 110 according to an embodiment and a plurality of user equipments, UEs, 120a-n forming a group of UEs 120a-n. In an embodiment, the base station 110 is configured to provide communication services, in particular network access for the plurality of UEs 120a-n and may be a base station or access point of a 3rd generation partnership project (3GPP) network, such as a 5G or 6G network, or of an IEEE 802.11 Wi-Fi network. In an embodiment, the base station 110 is configured to provide communication services to the UEs 120a-n for downlink (BS to UE information flow), uplink (UE to BS information flow) and / or sidelink (UE to UE information flow) communication. As illustrated in figure 1, the plurality of UEs 120a-n may comprise one or more mobile, in particular vehicular UEs embedded into a respective vehicular system, such as a car, truck, unmanned-aerial -vehicle (UAV), robot, autonomously guided vehicle (AGV), and the like. In an embodiment, these vehicular UEs 120a-n are capable of V2X: communication, i.e. configured to communicate with the infrastructure (i.e. the base station 110 and one or more further base stations) as well as other vehicular UEs. These UE to UE communications can occur directly (V2 V) or through the base station 110 as a proxy (V2N2V).

[0051] As illustrated in figure 1, the base station 110 may comprise a processing circuitry 111 and a communication interface 113, in particular a wireless communication interface 113, e.g. a transceiver 113 enabling communication in accordance with a 3GPP or the IEEE 802.11 framework of standards. The processing circuitry 111 of the base station 110 may be implemented in hardware and / or software and may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or general-purpose processors. The base station 110 may further comprise a memory 115 configured to store executable program code which, when executed by the processing circuitry 111, causes the base station 110 to perform the functions and methods described herein.

[0052] Likewise, as indicated in figure 1, each of the UEs 120a-n may comprise a processing circuitry 121 and a communication interface 123, in particular a wireless communication interface 123, e.g. a transceiver 123 enabling communication in accordance with a 3GPP or IEEE 802.11 framework of standards. The processing circuitry 121 of each UE 120a-n may be implemented in hardware and / or software and may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or general-purpose processors. Each UE 120a-n may further comprise a memory 125 configured to store executable program code which, when executed by the processing circuitry 121, causes the UE 120a- n to perform the functions and methods described herein.

[0053] Each of the UEs 120a-n is configured to operate according to a discontinuous reception, DRX, schedule, i.e. to save power by turning off communication components of the respective UE 120a-n in accordance with the DRX schedule when there is no data to be transmitted or received. These communication components embedded in the respective UE 120a-n may be communication components of the respective communication interface 123, such as one or more antennas, signal processing units, radio frequency elements, baseband processing units, and the like. As will be described in more detail below under further reference to figures 2 and 3, the base station 110 is configured to generate and transmit a DRX schedule configuration message to the group of UEs 120a-n and each UE 120a-n is configured to receive the DRX schedule configuration message from the base station 110. The DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs 120a-n. Moreover, the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE 120a-n of the group of UEs 120a-n. Thus, the base station 110 may efficiently manage the individual DRX behaviour as well as the group DRX behaviour of the group of UEs 120a-n with a single configuration message allowing to substantially reduce signalling overhead.

[0054] As illustrated in figure 2, the base station 110 may comprise a group DRX manager I l la, which in an embodiment may be implemented by the processing circuitry 110, for transmitting the DRX schedule configuration message to the group of UEs 120a-n. In an embodiment, the DRX schedule configuration message may be generated by the group DRX manager Il la based on input received from one or more computer applications 140 installed on the network side and / or UE side. On input to the group DRX manager 11 la the application 140 may provide timing requirements for separate communication services of each UE 120a-n. As already described, the group-DRX manager I l la output the DRX configurations, i.e. the DRX schedules (individual to each UE 120a-n in the group) within a single message that is simultaneously transmitted to all members in the group of UEs 120a-n. The single message may be duplicated along the way. To guarantee UE-UE reachability, in an embodiment, the UE DRX configurations, i.e. schedules are transparent to, i.e. can be read by other members of the group of UEs 120a-n. In the case that the UE group 120a-n is of the mobile / vehicular type, the group-DRX manager I lla may also receive messages on input that report the UEs’ path plan. In this case, the group-DRX manager I lla may introduce predictive capabilities for the DRX configurations, i.e. schedules based on the availability of future estimated / predicted trajectory to improve the efficiency of the DRX configurations, i.e. schedules in case of changing propagational environments.

[0055] In an embodiment, the single DRX schedule configuration message is adapted to configure the DRX operations of the UEs 120a-n for custom combinations of unicast communication services, multicast communication services, and / or sensing services. To this end, the DRX schedule configuration message may comprise or be indicative of a plurality of service identifiers, wherein each service identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a service of a plurality of services of a UE of the group of UEs 120a-n identified by the service identifier. As will be appreciated, a sensing service implemented by a respective UE 120a-n is a procedure during which the respective UE 120a-n observes its surroundings with the goal to infer the context of its situation. The observation can be full (entire knowledge of the situation is achieved) or partial (segmented knowledge of the situation is achieved and requires other pieces of information to achieve full knowledge). Sensing may require sending a sensing report to another device (e.g. the base station 110 or another UE 120a-n) that is affected by the observed situation. When the UE 120a-n uses the electromagnetic spectrum to perform sensing, the procedure is referred to as wireless sensing.

[0056] In an embodiment, the DRX schedule configuration message may further comprise or be indicative of a plurality of UE identifiers, wherein each UE identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a respective UE of the group of UEs 120a-n identified by the UE identifier. In an embodiment, the identity / identities of the UE / UEs to which the UE DRX configuration, i.e schedule applies may be combined with the identity / identities of each service, i.e. the service identifier that applies to each UE 120a-n within the group. Thus, embodiments disclosed herein enable optimized multi-service (unicast, multicast, sensing, etc.) DRX schedules for one or more UEs to be fully transparent between devices.

[0057] As illustrated, for instance, in figure 3, each UE DRX schedule defines a UE DRX cycle 301, 302 comprising a plurality of UE DRX cycle time slots or sub-slots 30 la-d, 302a-d. In an embodiment, the sub-slots may be signaled in two different manners. According to an embodiment, a separate slot in reference to the main unicast / multicast DRX slot may be used. In this embodiment, the configuration may specify two parameters that indicate both the starting and ending time of the sub-slot. In an alternative embodiment, a conjoint slot to the main unicast / multicast DRX slot may be used. In this embodiment, the configuration may specify only a singular parameter that indicates the ending time of the sub-slot.

[0058] In an embodiment, the DRX schedule configuration message is further indicative of one or more spatial regions, wherein the GROUP DRX schedule and / or the plurality of UE DRX schedules are valid only for the one or more spatial regions, i.e. when a respective UE 120a-n is located within the one or more spatial regions. In other words, according to an embodiment, the base station 110 is configured to inform a respective UE 120a-n of its spatially constrained area of a DRX configuration. This mechanism allows to provide each UE 120a-n with recommended DRX configurations for areas that the respective UE 120a-n is going to pass through in the future. To this end, in an embodiment, a path-plan or predicted trajectory information is present at the base station 110 so that the relevant areas can be identified.

[0059] As already described above, each UE 120a-n is configured to receive the DRX schedule configuration message from the base station 110. Based on the information contained in the DRX schedule configuration message each UE 120a-n may manage its DRX sleep slots, generate messages with recommendations for transmission behavior to the communications components based on the group-DRX configuration, and generate messages with recommendations for computer applications that generate data streams for specific services.

[0060] In the embodiment shown in figure 2, the DRX manager entity I l la may be co-located with the base station 110 or colocated with an entity that oversees the operation of one or more base stations, including the base station 110. As already described above, the DRX manager entity 11 la is responsible for the management of DRX slots for the UEs 120a-n that belong in a communication group. The communication groups can be, but not necessarily, vehicular UEs 120a-n that partake in V2X communication. The UEs 120a-n may be commonly grouped with other UEs that use the same uplink / downlink communication services and / or are expected to communicate to each other directly (sidelink) or indirectly (uplink-downlink through the network).

[0061] In a typical scenario each UE 120a-n may register itself for the wireless communication services along with a report for its capability to support DRX and its participation in sensing activities. However, because DRX reduces the reachability of UEs 120a-n relevant to the sensing process, DRX activation is conventionally not used with sensing. DRX defines long and short cycles, where the latter is mostly used for retransmission reachability. Traditionally, UE reachability during DRX on periods is improved through the Inactivity Timer mechanism that keeps the UE on for a longer period than the one dedicated for communications. DRX configuration mainly configures the long cycle, the DRX ON duration and inactivity timer. To stop the DRX cycles a wakeup signal needs to be transmitted to the UE in a period in which the UE is reachable.

[0062] One or more computer applications 140 may exist on the respective UE 120a-n, on another UE 120a-n in the group, and / or the wireless communication system connected to the base station 110. Such an application 140 may create a data stream that is relevant to the UE group 120a-n entirely, or to a specific individual UE 120a-n within the group, or that can be part of a more complex communication pattern that is conditional on other UEs and their responses. The application 140 may define timing requirements for each step of communication for the group of UEs 120a-n. The timing requirements and their appropriate services are then transmitted over an interface / network that reaches the group-DRX manager I lla, which may be implemented by the base station 110. If the application 140 supports path-plan reporting, the path-plan report may be transferred over said communication interface / network as well. The group-DRX manager I lla may be connected through a wireless control information transfer interface, or a series of wired or wireless interfaces, to all UEs 120a-n in the UE group. The group-DRX manager I lla may use this interface to transmit the DRX configuration message including the configurations that are generated based on the requirements of the one or more applications 140. Each 120a-n UE then may configure its DRX slots according to the group-DRX recommendation.

[0063] As already described above, the application 140 may implement a sensing process. An important metric with regards to a sensing report is the age of information. As used herein, age of information may be defined as the time elapsed since the latest piece of information received from a source of information. Since the source of information is expected to reflect a physical phenomenon, age of information is usually computed from the sensor that is the closest to the real-life time of the phenomenon occurrence. Receiving a piece of information that has low age of information can also be referred to as information freshness. There are several sensing scenarios that involve both UEs 120a-n and the BS 110, the most important being the multi-static sensing process and the mono-static sensing process. The multi-static sensing process considers a sensing signal that reflects off the environment towards each UE 120a-n and the BS 110. Each individual reflection of the sensing signal is insufficient to construct a view of the environment, thus multiple reflections need to be aggregated for a view to be constructed. The mono-static sensing process involves a singular UE 120a-n that coordinates the transmission and / or reception of sensing signals by itself. As such the sensing application on the UE 120a-n needs to find the ideal time in order to sense the freshest information of the critical entity / event to send to another UE 120a-n or the BS 110.

[0064] As already described above, the base station 110, e.g. the group-DRX manager 11 la is adapted for simultaneous DRX configuration at more than one 3GPP UEs 120a-n. Embodiments disclosed herein may be based on the 3GPP multicast DRX implementation DRX-ConfigPTM (DRX configuration point to multipoint message) capable of reserving a single DRX configuration that is synchronized for all recipient UEs 120a-n. To reserve unique, service dedicated slots, an information element containing an identifier of the target UE of a configuration may be added. The rest of the ID labelled information element may be followed by state-of-the-art unicast configuration information elements.

[0065] Embodiments disclosed herein not only reduce the number of messages dedicated for sending configurations to each member of the group of UEs 120a-n separately, but also allows for DRX configuration information sharing between the group members. As already described above, according to an embodiment each UE 120a-n is capable of reading the group-DRX configuration, and associate the DRX ID to members in the group it has communication links with. Attaining this knowledge allows for direct UE-UE communication without prior negotiation between both devices on how to set the DRX configurations.

[0066] Figure 4 shows a schematic diagram illustrating the sending of a DRX schedule configuration message from the base station 110 according to an embodiment to the group of UEs 120a-n according to an embodiment for an exemplary multi-static sensing application for sensing a target 150, for instance, a bicycle 150. This embodiment allows for an optimized DRX slot allocation for the group of UEs 120a-n that partake in multi-static sensing and the respective multicast or unicast slot at the users concerned with the sensing report. In the embodiment shown in figure 4, the base station 110 comprises in addition to the group DRX manager 11 la a sensing manager 11 lb, which, in turn, comprises a sensing data fusion entity 111c and a sensing quality evaluation entity 11 Id.

[0067] In a first stage of figure 4 the group DRX (gDRX) management entity I l la implemented by the base station 110 receives some preliminary requirements for the duration and processing of the sensing from the sensing quality evaluation entity 11 Id. Based on this information, the group DRX manager I lla implemented by the base station 110 generates the configuration message, including the DRX schedules (as illustrated in figure 3) for the group of UEs 120a-n (see stage 2 of figure 4). Following the configuration, the sensing process starts in stage 3 of figure 4 by sending the sensing signal to reflect off the target 150. The group of UEs 120a-n follows with the sensing reflection update sent to the sensing data fusion entity 111c in stage 4 of figure 4. The sensing result is then forwarded to the concerned entities. Given the quality of the sensing, the sensing quality evaluation entity 11 Id may update the sensing and processing duration requirements to the group DRX manager I lla implemented by the base station 110.

[0068] As illustrated in figure 5 and will be described in more detail below, in an embodiment, the group DRX manager 111 implemented by the base station 110 is configured to optimize the timing difference between the respective DRX sensing slot 301b, 304b and the respective slot where the information is being reported to the other users, i.e. the slots 301a, 304a. If the timing is larger than necessary, longer than necessary time elapses since the sensed data has been collected. If the timing is shorter than necessary, the opportunity to transmit on the closest transmission slot is lost and the next one will come in the next DRX cycle. Both shorter and longer timing differences than the necessary processing slot result in increasing the age of information of the sensed data.

[0069] While many implementations of multi-static sensing exist the most important steps are the sensing signal transmission and reflection reception, reflection information upload, sensor fusion (the processing of all reflections to create a single view), sensing report. Some sensing implementations exist that combine the reflection information upload and the sensor fusion in one step. Additionally, the sensing report can be omitted if no important information is extracted that needs reporting. For the purpose of completeness, the embodiment considers all aforementioned steps and no generality is lost if a step is skipped or modified.

[0070] In an embodiment, the BS 110 or the respective UE 120a-n are configured to report on the required time to perform reflection information upload, and the entity 11 Id performing the sensor fusion (which may be implemented by the BS 110) may be configured to report the processing time of the sensor fusion. The collective time of both processes may be referred to as negative-offset, since it refers to the negative time offset to the DRX slot of the final recipient.

[0071] To enable multi-static sensing and DRX compatibility, according to an embodiment, three additional pieces of information may be transmitted by means of the DRX configuration message, namely a DRX negative-offset, a DRX sensing Occurrence, and a DRX sensing Duration, as will be described in more detail in the following. Having calculated the negative-offset requirements, the group DRX management entity I l la implemented by the base station 110 may sends the DRX configuration message for the sensing slot and the listening slot for the sensing report. In an embodiment, the sensing report may be send on the multicast slot so that all UEs 120a-n in the group that are part of the service can receive it, which in part or in full may not be the same UEs that partake in the sensing. Thus, the DRX negative-offset is the timing difference in reference to the multicast slot dedicated to the downlink sensing report. If the sensing slot does not need to occur as regularly as a slot dedicated to the downlink sensing report, it may be specified with regards to how many slots are skipped. To specify how many slots are skipped the DRX sensing Occurrence may be specified. This information element can be skipped if the sensing occurs with the same regularity of the multicast slot. The sensing period of the multi-static sensing may depend on the used sensing technology, its limitations and requirements for the transmission of the sensing signal and the reception of its reflection at all members of the sensing group.

[0072] Figure 6 shows a schematic diagram illustrating the sending of a DRX schedule configuration message from the base station 110 according to an embodiment to first UE 120a and a second UE 120b of the group of UEs 120a-n according to an embodiment for a further exemplary multi-static sensing application. In the embodiment shown in figure 6, the base station 110 comprises in addition to the group DRX manager 11 la a V2N2V router 11 le. In figure 6 the procedure starts with a first stage, wherein the gDRX configuration, i..e the DRX schedules are sent from the group DRX manager I lla implemented by the base station 110 to the group of UEs including the illustrated UEs 120a and 120b. Given a sensing target 150 (in a mono -static sensing scenario of UE1 120a alone) the object may be tracked by the onboard sensors 127 of the UE1 120a. However, since UE1 120a is aware of the active slot of UE2 120b, namely slot UC2, the UE1 120a may in stage 2 of figure 6 request an allowance for an uplink or sidelink transmission directed to UE2 120b at the exact moment of slot UC2 (as will be appreciated this request should happen before slot UC2). In response to this request, the router 11 le implemented by the base station 110 grants this request for the transmission (see stage 3 of figure 6). Once granted, the first UE1 120a provides its last (freshest) sensing capture of the target 150 via the base station 110 to the second UE2 120b to avoid having an old capture, i.e. old data of the target 150 for the second UE2 120b (see stages 4 and 5 of figure 6).

[0073] The embodiment shown in figure 6 allows for age of information minimization of mono-static sensing reports from the first UE 120a to the second DRX activated UE 120b from the same group. The UEs 120a, b are expected to communicate within the management area of the group DRX manager I l la implemented by the base station 110. In the embodiment illustrated in figure 6, by way of example, the first UE 120a (referred to as UE1 in figure 6) may be the source of continuously sensed data, while the second UE 120b (referred to as UE2 in figure 6) is the recipient of a sending report. For the first UE 120a to transmit data to the second UE 120b it may forward the data via the network. The first UE 120a may send the report by sending it via the uplink to its BS 110 which forwards the data to the second UE 120b in downlink at its dedicated unicast DRX slot.

[0074] In a conventional system, UE1 would transmit the sensing report immediately to the concerned UE2 in an effort to reduce latency. Lacking knowledge of the DRX configuration forUE2, UE1, however, risks transmitting stale information due to the sensing report waiting to be scheduled for downlink transmission, thus increasing the staleness of the information. The group-DRX configuration implemented by embodiments disclosed herein enables the first UE 120a to reduce the age of information by transparently sharing the DRX configuration of all individual UE configurations within the group to all group members. Containing the information for the unicast slot of the second UE 120b (indicated as slot UC2 in figure 6), the first UE 120a may sample the last piece of sensing data before transmitting the freshest information in uplink that is ready for downlink transmission at the BS 110 before slot UC2 occurs. To enable the unicast DRX transmission to the UC2, the first UE 120a may be configured to perform a scheduling request for the end-to-end transmission.

[0075] In a further embodiment implementing an optimization technique for the group-DRX mechanism to enable DRX for applications 140 that require age of information minimization, as in the case of multi-static sensing, the DRX manager I l la implemented by the base station 110 may (as already described above) produce three parameters to indicate the multi-static sensing configuration parameters: sensing duration, negative-offset and sensing occurrence. The sensing occurrence and the sensing duration may be directly provided by the sensing management entity 111b illustrated in the embodiment of figure 4. Thus, the DRX manager 11 la is left to optimize and indicate a DRX-negative-offset parameter based on its awareness of the communications. The offset requirement may be defined in milliseconds by:

[0076] DRX-negative-offset = UE_processing + UE-BS_uplink + BS_processing, where the B S_processing is given by the sensing entity 11 lb, the UE_processing parameter is stochastic and due to privacy cannot be communicated to the BS 110, and the UE-BS_uplink parameters is highly stochastic and depends on the uplink speed of each UE 120a-n separately. Since the BS_uplink can vary widely between participating UEs 120a-n, some UEs 120a-n that take too long to upload their observations may be dropped. If the sensing application 140 does not have enough observations to construct a good view of the situation, it may report this through the sensing_quality_report to the DRX entity I l la. The sensing_quality_report may vary from perfect to insufficient (represented by a real number between 1 and 0).

[0077] In this embodiment, the goal of the DRX management entity 11 la is to minimize the DRX-negative-offset without negatively affecting the sensing quality. To achieve this, the DRX manager I l la may be configured to employ a machine learning implementation that consists of input data, forward propagational memory structure, and output data. The input data may consist of the number of UEs 120a-n, their individual channel performances, and the sensing quality expected. The memory, often referred to as artificial neural network, may be a fully connected forward flowing layered graph where the relationships between graph layers are stored in memory. The output of the artificial neural network is the estimated DRX-negative-offset to be used for the configuration.

[0078] In order to start using the machine learning the artificial neural network may be trained to offer the required performance. To train the artificial neural network the output may be compared with the true minimal DRX-negative-offset with a mean square error loss function: where YLis the true minimum DRX-negative-offset, and is the DRX-negative-offset estimated by the artificial neural network. Using gradient descent, the loss L may propagated through the artificial neural network using the backwards propagation algorithm to correct for the errors in each layer of the artificial neural network. The process may be repeated to improve the performance of the machine learning algorithm and can be stopped whenever the performance of the estimator is deemed satisfactory.

[0079] Embodiments disclosed herein provide, amongst others, the following advantages. A significant reduction in signaling overhead is made possible when setting DRX for UE groups that need to know each other’s configurations. Having slots and sub-slots for DRX configuration of separate unicast / multicast service flows avoids a UE having to go through complex and energy consuming operations unnecessarily to correspond for services it does not participate in. Such an operation that reduces energy-efficiency is the inactivity timer of DRX that delays the DRX sleep cycle upon the reception of information. Moreover, DRX compatibility with sensing applications is achieved and UE battery life may be extended due to DRX configurability when sensing is enabled. Spatially dynamic DRX configurations that the UE can switch between upon the recommendation of the group-DRX entity avoids corresponding for services that cannot be performed when channel conditions change due to expected low service coverage. Moreover, this allows for easier adaptability of DRX when channel conditions are poor and messages might not reach the UE anyway. Group level DRX optimization for application data streams allows addressing application-level timing metrics to satisfy more stringent constraints. This allows the use of DRX in more time critical scenarios and use cases.

[0080] Figure 7 shows a flow diagram illustrating a method 700 of operating the base station 110 according to an embodiment. The method 700 comprises a step 701 of transmitting a discontinuous reception, DRX, schedule configuration message to the group of UEs 120a-n, wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs 120a-n. The DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE 120a-n of the group of UEs 120a-n.

[0081] The method 700 can be performed by the base station 110. Thus, further features of the method 700 result directly from the functionality of the base station as well as the different embodiments thereof described above and below. Figure 8 shows a flow diagram illustrating a method 800 of operating a UE, such as the UE 120a, according to an embodiment. The method 800 comprises a step 801 of receiving a discontinuous reception, DRX, schedule configuration message from the base station 110, wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs 120a-n, including the UE 120a. The DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE 120a-n of the group of UEs 120a-n, including a UE DRX schedule associated with the UE 120a.

[0082] The method 800 can be performed by any one of the UEs 120a-n, for instance, the UE 120a. Thus, further features of the method 800 result directly from the functionality of the UEs 120a as well as the different embodiments thereof described above and below.

[0083] The person skilled in the art will understand that the "blocks" ("units") of the various figures (method and apparatus) represent or describe functionalities of embodiments of the present disclosure (rather than necessarily individual "units" in hardware or software) and thus describe equally functions or features of apparatus embodiments as well as method embodiments (unit = step).

[0084] In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the described embodiment of an apparatus is merely exemplary. For example, the unit division is merely a logical function division and may be another division in an actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.

[0085] The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

[0086] In addition, functional units in the embodiments of the disclosure may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units may be integrated into one unit.

Claims

CLAIMS1. A base station (110) for communication with a group of user equipments, UEs, (120a-n), wherein the base station(110) is configured to: transmit a discontinuous reception, DRX, schedule configuration message to the group of UEs (120a-n), wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs (120a-n) and wherein the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE (120a-n) of the group of UEs (120a-n).

2. The base station (110) of claim 1, wherein each UE DRX schedule of the plurality of UE DRX schedules is readable by each UE (120a-n) of the group of UEs (120a-n).

3. The base station (110) of claim 1 or 2, wherein the DRX schedule configuration message is further indicative of a plurality of UE identifiers and wherein each UE identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a UE (120a-n) of the group of UEs (120a-n) identified by the UE identifier.

4. The base station (110) of any one of the preceding claims, wherein the DRX schedule configuration message is further indicative of a plurality of service identifiers and wherein each service identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a service of a plurality of services of a UE (120a-n) of the group of UEs (120a-n) identified by the service identifier.

5. The base station (110) of claim 4, wherein the plurality of services comprises a multicast service, a unicast service, and / or a sensing service.

6. The base station (110) of claim 4 or 5, wherein the base station (110) is configured to generate the GROUP DRX schedule and / or the plurality of UE DRX schedules based on timing requirements of the plurality of services.

7. The base station (110) of any one of the preceding claims, wherein each UE DRX schedule defines a UE DRX cycle (301, 302) comprising a plurality of UE DRX cycle time slots (301a-d, 302a-d).

8. The base station (110) of any one of the preceding claims, wherein the DRX schedule configuration message is further indicative of one or more spatial regions and wherein the GROUP DRX schedule and / or the plurality of UE DRX schedules are valid only for the one or more spatial regions.

9. The base station (110) of claim 8, wherein the base station (110) is configured to obtain a path plan for each UE( 120a-n) of the group of UEs ( 120a-n) and to generate the GROUP DRX schedule and / or the plurality of UE DRX schedules based on the plurality of path plans of the group of UEs (120a-n).

10. The base station (110) of any one of the preceding claims, wherein the base station (110) is further configured to transmit a sensing signal or to trigger transmission of a sensing signal and wherein one or more UEs (120a-n) of the group of UEs (120a-n) are configured, based on the GROUP DRX schedule and / or the plurality of UE DRX schedules, to receive the sensing signal and / or a signal based on the sensing signal during the transmission of the sensing signal.

11. A method (700) for communication between a base station (110) and a group of user equipments, UEs, (120a-n), wherein the method (700) comprises: transmitting (701) a discontinuous reception, DRX, schedule configuration message to the group of UEs (120a-n), wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs ( 120a-n) and wherein the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE (120a-n) of the group of UEs (120a-n).

12. A user equipment, UE, (120a-n) for communication with a base station (110), wherein the UE (120a-n) is configured to: receive a discontinuous reception, DRX, schedule configuration message from the base station (110), wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for a group of UEs (120a-n), including the UE (120a-n), and wherein the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE (120a-n) of the group of UEs (120a-n).

13. The UE (120a-n) of claim 12, wherein the UE (120a-n) is configured to read each of the plurality of UE DRX schedules of the DRX schedule configuration message.

14. The UE (120a-n) of claim 13, wherein the UE (120a-n) is configured to schedule, based on the plurality of UE DRX schedules, a transmission to one or more further UEs (120a-n) of the group of UEs (120a-n).

15. The UE (120a-n) of any one of claims 12 to 14, wherein the DRX schedule configuration message is further indicative of a plurality of UE identifiers and wherein each UE identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a UE (120a-n) of the group of UEs (120a-n) identified by the UE identifier.

16. The UE (120a-n) of any one of claims 12 to 15, wherein the DRX schedule configuration message is further indicative of a plurality of service identifiers and wherein each service identifier associates a UE DRX schedule of the plurality of UE DRX schedules with a service of a plurality of services of the UE (120a-n) identified by the service identifier.

17. The UE (120a-n) of claim 16, wherein the plurality of services comprises a multicast service, a unicast service, and / or a sensing service.

18. The UE (120a-n) of any one of claims 12 to 17, wherein each UE DRX schedule defines a UE DRX cycle (301, 302) comprising a plurality of UE DRX cycle time slots (301a-d, 302a-d).

19. The UE (120a-n) of any one of claims 12 to 18, wherein the DRX schedule configuration message is further indicative of one or more spatial regions and wherein the GROUP DRX schedule and / or the plurality of UE DRX schedules are valid only for the one or more spatial regions.

20. A method (800) for communication between a user equipment, UE, (120a-n) of a group of UEs (120a-n) and a base station (110), wherein the method (800) comprises:receiving (801) a discontinuous reception, DRX, schedule configuration message from the base station (110), wherein the DRX schedule configuration message is indicative of a GROUP DRX schedule defining a DRX schedule for the group of UEs (120a-n), including the UE (120a-n), and wherein the DRX schedule configuration message is further indicative of a plurality of UE DRX schedules, wherein each of the plurality of UE DRX schedules is associated with one UE (120a-n) of the group of UEs (120a-n).

21. A computer program product comprising a computer-readable storage medium for storing program code which causes a computer or a processor to perform the method (700) of claim 11 or the method (800) of claim 20 when the program code is executed by the computer or the processor.

Images