Method for sidelink beam management in wireless networks

Abstract

A method for sidelink beam management in a wireless network is provided, which comprising the steps of periodically sending channel state information reference signals (CSI-RS) over one or more beams and executing a Beam Failure Detection (BFD) or a Candidate Beam Determination (CBD) procedure for said one or more beams, based on the receiving of said reference signals. The periodicity of said sending is adjusted based on one or more criteria, which may relate to a congestion level, a priority level and / or a mobility level. The method may further comprise the step of determining said congestion level in a channel, preferably in all directions, or at a beam level, preferably using one or more wide beams.

Description

METHOD FOR SIDELINK BEAM MANAGEMENT IN WIRELESS NETWORKSBACKGROUNDNext generation wireless networks, for example 5G New Radio (NR), may use millimeter wave (mmW) communication between a base station and a user equipment (UE). Radio waves with wavelengths between 1 millimeter and 10 millimeters may be referred to as millimeter waves. More specifically, next generation wireless networks may use so called Frequency Range 2, i.e. 25-52 GHz. Wireless communication using an mmW radio frequency band generally has higher path loss and a shorter range than those of lower frequencies.In 5G NR, the base station (which may be referred to as gNB (next generation NodeB)) and UE (User Equipment) may use beamforming techniques to compensate for the high path loss and short range of mmW communication. This approach can also be used for communication between two UEs, such as Car-to-Car Communication or Car-to-lnfrastructure communication. A communication link between two UEs may be referred to as a sidelink.Beamforming is a signal processing technique used with an antenna array for directional signal transmission and / or reception. Each antenna in the antenna array transmits a signal that is combined with other signals of other antennas of the same array in such a way, that signals at particular angles experience constructive interference while others experience destructive interference. The constructive interference may create one or more beams of signals.In beamformed signal transmission, the amplitude and phase of signal transmitted from each antenna in an antenna array may be controlled (e.g., pre-coded, weighted) to create a predetermined (e.g., directional) pattern of constructive and destructive interference in the wavefront. Therefore, a signal beam (referred to as "beam") may provide more energy or range in a certain direction to the receiver.As the demand for mobile broadband access continues to increase, research and development continue to advance communication using beamforming techniques to mitigate the high path loss and short range of mmW wireless communication.According to the definition provided for NR Uu (Radio Interface) in 3GPP TR 38.802, SL (sidelink) beam management is to “acquire and maintain a set of [UE] beams that can be used for [SL] transmission / reception”. The general framework of SL Beam Management comprises procedures for (i) initial beam pairing, (ii) beam reporting and maintenance, and (iii) sidelink beam failure indication.The objective of this application is to further improve the procedure for (ii) beam reporting and maintenance and (iii) sidelink beam failure indication.SUMMARYThe objective of the invention is met by providing a method according to claim 1 and a User Equipment according to claim 13.According to a first aspect, a method for sidelink beam management in a wireless network is provided, the method comprising the steps of- periodically sending channel state information reference signals (CSI-RS) over one or more beams- executing a Beam Failure Detection (BFD) or a Candidate Beam Determination (CBD) procedure for said one or more beams, based on the receiving of said reference signals; wherein the periodicity of said sending is adjusted based on one or more criteria.The wording “wireless network” may refer to 5G and new radio access technology undergoing definition and standardization by 3GPP in Release 15. The wording may also refer to other systems defined by 3GPP, such as Long-Term Evolution (LTE), the Evolved Packet System (EPS), the Universal Mobile Telecommunication System (UMTS), and / or the Global System for Mobile (GSM). The wording may also refer to systems defined by the 3rd Generation Partnership Project 2 (3GPP2), such as CDMA2000 and / or Evolution-Data Optimized (EV-DO) or to systems employing IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra- Wideband (UWB), Bluetooth, and / or other suitable systems.For continuous Beam Failure Detection (BFD) or a Candidate Beam Determination reference signals can be transmitted all the time in different beams, even when there is no traffic on a respective data channel. This may be a potentially waste of power used for transmitting and receiving the reference signals as well as source of reference signal-contamination. Furthermore, transmitting more reference signals (more often, i.e. , smaller periodicity) provides the advantage that UE can monitor the quality of the beamsmore frequently, but at the same time, this potentially creates more interference to other users. The trade-off between these advantages and disadvantages is addressed in this invention.Therefore, it is advantageous to adjust the number of slots with reference signals sent per time unit (i.e. , the periodicity of sending the reference signal) based one or more (a combination of) criteria. In that case, less reference signals are sent when BFD or CBD may be executed later or less frequently.Beam Failure Detection (BFD) and Candidate Beam Determination (CBD) procedures may be used in Sidelink Beam Management, in particular in beam reporting and maintenance and sidelink beam failure indication.According to the invention, the reference signals are channel state information reference signals (CSI-RS). Alternatively, S-SSBs (sidelink synchronization signal blocks) may be used as reference signals.According to one or more embodiments, said one or more criteria relate to a congestion level, a priority level and / or a mobility level. Indeed, it may be advantageous to execute the BFD and / or CBD procedures more frequently when a congestion level in the network is high, as new channels or beams may be needed to reduce the congestion or to quickly compensate for beam failures.Furthermore, it may be advantageous to execute the BFD and / or CBD procedures more frequently when the data to be transmitted has a high priority (i.e., requires a low packet loss, low latency and / or low jitter) or when the UE has a high priority. Also, in the case that one or both UEs are moving with respect to each other, the availability and quality of the beams may vary. A higher mobility level, indicating a more or faster movements, may require a more frequent execution of the BFD and / or CBD procedures. In general, more frequent execution of the BFD and / or CBD procedures may require more reference signals to be sent per time unit or sent per data frame, i.e., higher periodicity.According to one or more embodiments, the method further comprises the step of determining said congestion level in a channel, preferably in all directions, or at a beam level, preferably using one or more wide beams. And, according to one or moreembodiments, said congestion level is determined based on a channel busy ratio (CBR) and / or a channel occupancy ratio (CR).When using the CR, the congestion is measured based on how much the channel is used by the measuring entity itself. In case of CBR, the congestion is measured based on how much the channel is used by other entities.According to one or more embodiments, a mapping between said one or more criteria and a pre-determined periodicity is stored in a table. It may be advantageous to quickly look-up the required periodicity in a certain situation in a table, in which a mapping between criteria and periodicity values is stored. For example, a congestion above a predefined level X (e.g. , 30%) may indicate that the periodicity is to be adjusted to Y slots for reference signals.In one or more embodiments, the table may comprise a default mapping, indicating the periodicity of sending reference signal when no other mapping is available. For example, when the UE is not within reach of an entity that provides another mapping, such as gNB.According to one or more embodiments, wherein said mapping is based on system information provided by a base station of said wireless network, i.e., the base station determines a certain periodicity or that a certain situation requires a certain periodicity. The mapping may also be based on pre-coded information in the specification and / or negotiated during the connection set-up. According to one or more embodiments, the mapping may also be adjusted over time.In or more embodiments, multiple mappings can be stored in said tables and wherein each mapping is identified by a respective reference. In one or more further embodiments, one of said respective reference sign is transmitted in order to indicate the mapping to be used.It may be advantageous to have a table with mappings present in a UE and to transmit only a reference in order to change the mapping to be used. In that case, only a reference needs to be transmitted instead of all the information needed for a completely new mapping.According to one or more embodiments, each mapping relates to one or more beams. Since the congestion level may be measured for one or more beams, it may be advantageous to provide different mappings independently for different beams.According to other aspects of the invention, a computer program comprising instructions which, when the program is executed by a computer processor, cause the computer processor to carry out the steps of any method as described in this document. Furthermore, a computer-readable medium having stored thereon this computer program.According to yet another aspect of the invention, a User Equipment (UE) is provided comprising a processor and computer-readable medium according to claim 9, wherein said User Equipment (UE) is arranged for executing the steps of any method as described in this document. According to another aspect of the invention a vehicle is provided comprising such a UE.Furthermore, a wireless communication system with network devices is provided, wherein said network devices are arranged for being connection to each other using a wireless network and comprise at least one base station and at least two UEs as described in this document.The working, advantages and embodiments of the UE, the vehicle and the system as well as the working, advantages and embodiments of the computer program and computer-readable medium, correspond with the working, advantages and embodiments of the method as described in this document, mutatis mutandis.BRIEF DESCRIPTION OF THE DRAWINGSFor a more complete understanding of the present invention, reference in the following description is made to the accompanying drawings in which:Fig. 1 shows a schematic illustration of a wireless communication system;Fig. 2a and 2b show a schematic illustration the data transmission scenario between UE1 and UE2;Fig. 3 shows a schematic overview of a method according to one or more embodiments of the invention; and,Fig. 4. shows a schematic overview of a vehicle according to one or more embodiments of the invention.DETAILED DESCRIPTIONFig. 1 shows a schematic illustration of a wireless communication system 100 comprising a base station (gNB) 110, a first User Equipment (UE1) 120 and a second User Equipment (UE2) 130.The wireless communication system 100 may be said to include three interacting domains: a core network, a radio access network (RAN), and a user equipment (UE1 or UE2). The user equipment (UE) can be a stand-alone device or can be integrated in a vehicle like it is shown in Fig. 4. By virtue of the wireless communication system 100, a UE may be enabled to carry out data communication with an external data network, such as (but not limited to) the Internet.For communication between the gNB and the UE1 and UE2 several beams 140 may be available. Paring of beam t2 may enable communication between the gNB and UE1 and paring of t1 may enable communication between the gNB and UE2. In the same way beam technology may be used for communication between UE1 and UE2, using sidelink beams 150.Fig. 2a and 2b show a schematic illustration the data transmission scenario between UE1 and UE2. In Fig 2a and 2b, the UE1 and UE2 are embodied in a first vehicle 210 and a second vehicle 220, respectively. In Fig 2a, data is being transmitted between UE1 and UE2 using a side link with paired beams. In Fig. 2b, no data is being transmitted between UE1 and UE2, although many beams are available. In one or more embodiments, the periodicity of sending channel state information reference signals (CSI-RS) is not identical for all beams.In some embodiments, the non-limiting term user equipment (UE) or wireless device may be used and may refer to any type of wireless device communicating with a network node and / or with another UE in a cellular or mobile communication system. Examples of UE are target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine (M2M) communication, PDA, PAD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, UE category Ml, UE category M2, ProSe UE, V2V UE, V2X UE, etc.Fig. 3 shows a schematic overview of a method 300 according to one or more embodiments of the invention. The method 300 comprises the following steps:

[0310] periodically sending channel state information reference signals (CSI-RS) over one or more beams; and,

[0320] executing a Beam Failure Detection (BFD) or a Candidate Beam Determination (CBD) procedure for said one or more beams, based on the receiving of said reference signals; wherein the periodicity of said sending is adjusted based on one or more criteria. The one or more criteria may relate to a congestion level, a priority level and / or a mobility level.Method 300 may further comprise step 330 of determining said congestion level in a channel, preferably in all directions, or at a beam level, preferably using one or more wide beams, said priority level and / or said mobility level. The congestion level may be determined based on a channel busy ratio (CBR) and / or a channel occupancy ratio (CR).A mapping between the one or more criteria and a periodicity may be stored in a table. Each mapping table may be referred to with a reference. Examples of such mapping tables are provided below.The table above shows a generic, single criteria mapping table with reference M1. Below such a table is provided with a congestion level as criterium.The mapping table M2 below has the same structure as the mapping table M1 , but with different periodicities. The mapping is thus said to be different.In two further examples, mappings M3 and M4 are based on multi-criteria as shown in the tables below:Mappings 3 and 4 take into consideration the priority of data to be transmitted (having for example a priority 1 or a priority 2) and the mobility of the UE (which is expressed for example as a velocity of the UE).In one or more embodiments, the mapping is defined by a formula. For example, in mapping5, the periodicity in slots may be defined by the measured congestion in a percentage divided by 10. In a mapping 6, the periodicity in slots may be defined by the measured congestion in a percentage divided by 4.In one or more embodiments, data is transmitted in data frames between UEs. Each frame may comprise multiple slots (or blocks). A channel state information reference signal(CSI-RS) may be comprised in one slot or in one block. A high periodicity may then indicate that more slots with a CSI-RS per time unit are transmitted.A mapping may be established based on system information provided by a base station of said wireless network; and / or, pre-coded information in the specification; and / or, negotiation or settings in the connection set-up. The mapping may be adjusted over time.In one or more embodiments, a mapping table may be present in the UE. When a mapping needs to be changed (for example, from mapping 1 to mapping 3 as indicated in the table above), only the reference to the new mapping may need to be transmitted. In the example thus only the number “3”.Fig. 4. shows a schematic overview of a vehicle 400 according to one or more embodiments of the invention, which comprises a UE 410. The UE 410 is arranged for executing the steps according to any of the methods as described in this document. In general, a vehicle may be a car, a motorbike, a van, a truck, a bicycle or a scooter.Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and / or program code, referred hereafter as code. The storage devices may be tangible, non- transitory, and / or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (“RAM”), a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM” or Flash memory), a portable compact disc read-only memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computerreadable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object- oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the “C” programming language, or the like, and / or machine languages such as assembly languages. The code may execute entirely on the user’s computer, partly on the user’s computer, as a stand-alone software package, partly on the user’s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user’s computer through any type of network, including a local area network (“LAN”), wireless LAN (“WLAN”), or a wide area network (“WAN”), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider (“ISP”)).The applications DE 10 2023 207 566 and DE 10 2023 207 565 are incorporated by reference into this application.Aspects of the invention are explained in the detailed description. Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments, it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, whereverappropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.Those of skill will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those of skill in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.The benefits and advantages that may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the claims. As used herein, the terms “comprises,” “comprising,” or any other variations thereof, are intended to be interpreted as non-exclusively including the elements or limitations which follow those terms. Accordingly, a system, method, or other embodiment that comprises a set of elements is not limited to only those elements, and may include other elements not expressly listed or inherent to the claimed embodiment.While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions andimprovements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention as detailed within the following claims.

Claims

CLAIMS1. Method for sidelink beam management in a wireless network, comprising the steps of- periodically sending channel state information reference signals (CSI-RS) over one or more beams;- executing a Beam Failure Detection (BFD) or a Candidate Beam Determination (CBD) procedure for said one or more beams, based on the receiving of said reference signals; wherein the periodicity of said sending is adjusted based on one or more criteria.

2. Method according to claim 1 , wherein said one or more criteria relate to a congestion level, a priority level and / or a mobility level.

3. Method according to claim 2, further comprising the step of determining said congestion level in a channel, preferably in all directions, or at a beam level, preferably using one or more wide beams.

4. Method according to claim 2 or 3, wherein said congestion level is determined based on a channel busy ratio (CBR) and / or a channel occupancy ratio (CR).

5. Method according to any of claims 1 to 4, wherein a mapping between said one or more criteria and a periodicity is stored in a table.

6. Method according to claim 5, wherein said mapping is based on: system information provided by a base station of said wireless network; and / or, pre-coded information in the specification; and / or, negotiation or settings in the connection set-up.

7. Method according to claim 5 or 6, wherein multiple mappings are stored in said table and wherein each mapping further comprises a respective reference.

8. Method according to claim 7, wherein one of said respective reference sign is transmitted in order to indicate the mapping to be used.

9. Method according to any claims 5-8, wherein each mapping relates to one or more beams.

10. Method according to any claims 5-9, wherein said mapping is adjusted over time.

11. A computer program comprising instructions which, when the program is executed by a computer processor, cause the computer processor to carry out the steps of the method of any of claims 1-10.

12. A computer-readable medium having stored thereon the computer program according to claim 11.

13. User Equipment (UE) comprising a processor and computer-readable medium according to claim 12, wherein said User Equipment (UE) is arranged for executing the steps according to any of claims 1-10.

14. Vehicle comprising User Equipment according to claim 13.

15. Wireless communication system with network devices, said network devices arranged for being connection to each other using a wireless network and comprising at least one base station and at least two UEs according to claim 13.

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