Methods and devices for power-efficient paging in a multi-beam wireless system

Abstract

The disclosure relates to a method, an apparatus, and a network node for receiving (203) one or more preferred beams or cells from a user equipment and for transmitting (206) a paging notification to said user equipment in idle or inactive state using said preferred beams or cells. The disclosure also relates to a method, an apparatus, and a user equipment for transmitting (201) a subset of preferred beams or cells in a message (202) to a network node and for receiving (208) a paging message (207) from a network node during an inactive or idle state.

Description

[0001] TITLE

[0002] Methods and devices for power-efficient paging in a multi-beam wireless system

[0003] TECHNICAL FIELD

[0004] The present disclosure generally relates to wireless communication and more particularly to a method for optimizing power consumption when paging a user equipment in inactive or idle state.

[0005] BACKGROUND

[0006] Wireless communication systems like LTE or 5G New Radio (NR) provide support for various types of communication, such as voice, video, packet data, messaging, broadcast, and so on. Such a communication system typically includes a number of base stations (BS) providing user equipment (UE) with wireless access to a core communication network.

[0007] 5G NR makes use of the millimeters waves spectrum to offer very high bandwidth. However, these high frequencies are subject to increased pathloss, channel intermittency, and may be blocked by many common materials, even user’s body, what may lead to rapid drops in signal strength. To mitigate these impairments, 5G NR makes use of highly directional transmission links what requires beamforming techniques to align the transmitter and receiver beams.

[0008] In order to reduce its power consumption, a user equipment may switch to an inactive or idle state when it does not have any ongoing data transmission. If new data arrives for the user equipment, a base station may probe the user equipment by sending a paging message.

[0009] Because gNB is not aware of the user equipment’s localization when it is in inactive or idle state, a paging message is transmitted over all beams of each cell in a RAN based notification area. However, repeating the same paging message in all transmitted beams increases signaling overhead and waste of radio resource of gNB which contribute to unnecessary energy consumption. There is therefore a need for a method for paging a user equipment in inactive or idle state with a reduced power consumption.

[0010] SUMMARY

[0011] According to a first aspect of the disclosure, a method of wireless communication by a network node for transmitting a paging notification to a user equipment in inactive or idle state is provided. The method comprises:

[0012] - Receiving from said user equipment, before said user equipment enters inactive or idle state, a configuration parameter including at least one preferred beam for receiving a transmission,

[0013] - Determining a subset of beams based at least on said at least one preferred beam received,

[0014] - Transmitting a paging request to said user equipment over said determined subset of beams.

[0015] The paging request is thus transmitted on a subset of beams selected by the base station according to beam preferences provided by the user equipment before it enters inactive or idle state. Because the paging message is transmitted only on a subset of beams, the power consumption is reduced.

[0016] According to an embodiment, the received configuration parameter further comprise a cell preference and the subset of beams is further determined based on said preferred cell.

[0017] The paging message is thus transmitted only within cells that are indicated as preferred cells by the user equipment. This way, power may be saved by avoiding useless transmission.

[0018] According to an embodiment, said configuration parameter is received in an Assistance Information message. The user equipment transmits indications regarding beams and cells preferences in a UEAssistancelnformation message. UEAssistanceMessage may be sent by UE to provide preferences, for example in response to a RRCReconfiguration request.

[0019] According to another aspect, the disclosure relates to an apparatus for transmitting a paging notification to a user equipment in inactive or idle state in a wireless network, said apparatus comprising a processor coupled with a memory in which computer program instructions are stored, said processor being configured by said instructions to perform step of:

[0020] - Receiving from said user equipment, before said user equipment enters inactive or idle state, a configuration parameter including at least one preferred beam for receiving a transmission,

[0021] - Determining a subset of beams based at least on said at least one preferred beam received,

[0022] - Transmitting a paging request to said user equipment over said determined subset of beams.

[0023] The present disclosure also contemplates a network node (e.g., a base station) comprising such an apparatus.

[0024] Another aspect of the disclosure relates to a method of wireless communication by a user equipment device for receiving a paging notification from a network node while in inactive or idle state, the method comprising:

[0025] - Determining one or more preferred beam based at least on user equipment location,

[0026] - Transmitting a configuration parameter to said network node before entering idle or inactive state, said configuration parameter including at least said one or more preferred beam,

[0027] - Receiving a paging request while in inactive or idle state from said network node, said paging request being transmitted by said network node on a subset of beams comprising said one or more preferred beam. A UE may thus indicate its one or more preferred beams to a network node (e.g., a base station) before entering inactive / idle state. Whenever a base station is willing to send a paging notification, said notification may be sent only over said preferred beams to avoid useless transmission. Thanks to UE determining its preferred beams according to at least its current location, it may still receive a paging notification event if said notification is sent over a limited subset of beams. UE may thus help a network node to save power.

[0028] According to an embodiment, the method further comprises a step of determining a mobility status of said user equipment, said configuration parameter comprising:

[0029] - a first number of beams when said mobility status indicates a stationary user equipment, and

[0030] - a second number of beams when said mobility status indicates a non-stationary user equipment, the second number of beams being greater than the first number of beams.

[0031] The number of preferred beams indicated in the configuration parameter thus depends on a mobility status of the UE. A limited number of beams may be indicated to the network node when the UE is determined stationary because beams configuration may not change, whereas a larger number of beams may be signaled as preferred when the UE is determined non-stationary or semi-stationary to cover potential new locations of the UE.

[0032] According to an embodiment, said configuration parameter further includes a cell preference, said received paging request being transmitted by a network node in a preferred cell.

[0033] This way, the method avoids transmitting paging notifications in cells where the target UE is not located. Power consumption is thus reduced.

[0034] According to an embodiment, said configuration parameter is transmitted in an Assistance Information message. According to an embodiment the step of determining at least one preferred beam further comprise:

[0035] - Determining a future localization of said user equipment, and

[0036] - Determining at least one beam configuration corresponding to said future localization.

[0037] A user equipment may determine its future location based on its current location and / or an history of its former location. Based on the determined future location, the user equipment may determine one or more beams and / or one or more cells that would match said future location. Knowing these one or more determined beams allows a network node to later transmit a paging message to the user equipment in inactive or idle state using only a subset of beams that best matches user equipment location.

[0038] Another aspect of the disclosure contemplates an apparatus for receiving a wireless paging notification from a network node while in inactive or idle state, said apparatus comprising a processor coupled with a memory in which computer program instructions are stored, said processor being configured by said instructions to perform step of:

[0039] - Determining one or more preferred beam based at least on user equipment location,

[0040] - Transmitting a configuration parameter to said network node before entering idle or inactive state, said configuration parameter including at least said one or more preferred beam,

[0041] - Receiving a paging request while in inactive or idle state from said network node, said paging request being transmitted by said network node on a subset of beams comprising said one or more preferred beam.

[0042] It is also contemplated a user equipment comprising an apparatus for receiving a wireless paging notification as described hereinabove.

[0043] The present disclosure further relates to a wireless communication system for transmitting a paging notification to a user equipment, said system comprising a network node for receiving a paging notification and a user equipment for receiving said paging notification as described above.

[0044] According to an embodiment, steps of the method for transmitting a paging notification to a user equipment and of the method for receiving said paging notification described hereinabove are determined by computer program instructions.

[0045] Consequently, an embodiment of the present disclosure relates to a computer program stored on an information medium, said program being suitable to be implemented in user equipment device or more generally in a computer, said program comprising instructions configured to implement steps of the methods for receiving a paging notification and / or the method for transmitting a paging notification which have just been described.

[0046] The program can use any programming language, and be in the form of source code, object code, or of code intermediate between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0047] A further aspect contemplates a computer-readable information medium comprising computer program instructions for implementing steps of the methods mentioned hereinabove.

[0048] The information medium may be any entity or device capable of storing the program. For example, the medium can comprise a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, FLASH memory or any magnetic recording means, for example a hard drive.

[0049] Moreover, the information medium may be a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by other means.

[0050] Alternatively, the information medium may be an integrated circuit into which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the methods in question.

[0051] The advantages of the apparatus, user equipment, network node, wireless system, computer program and information medium are identical to those presented in relation with the corresponding method according to any one of the embodiments mentioned hereinabove. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Other advantages and characteristics of the invention will be more clearly apparent on reading the following description, given by way of simple illustrative and nonlimiting example, and the appended drawings, among which:

[0053] - FIG. 1 is a schematic diagram of a wireless communication system in which aspects of the method disclosed herein may be practiced, according to an embodiment,

[0054] - FIG. 2 is a combined flow chart illustrating steps of the methods disclosed herein and messages exchanged, according to an embodiment of the present disclosure,

[0055] - FIG. 3 is a block diagram showing an architecture of an apparatus suitable to implement a method for transmitting a paging notification to a user equipment according to an embodiment,

[0056] - FIG. 4 is a block diagram showing an architecture of an apparatus suitable to implement a method for receiving a paging notification from a network node according to an embodiment.

[0057] DETAILED DESCRIPTION

[0058] The detailed description set forth below, with reference to annexed drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In particular, although terminology from 3GPP 5G NR may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the invention.

[0059] FIG. 1 shows an exemplary 5G New Radio (NR) wireless communication system 100 comprising a user equipment 101 and a base station 102 in which aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as 5G NR network. The wireless network 100 may include one or more base stations 102. The base station 102 may be referred as BS, NB, eNodeB (or eNB), gNodeB (or gNB), an access point or the like, depending on the wireless standard implemented. Base station 102 provide radio communication coverage for a cell 103. User equipment 101 may communicate with base station 102 through radio signals to access a core communication network (not shown). The base station 102 may communicate with user equipment 101 using downlink (DL) and uplink (UL) radio channels.

[0060] User equipment 101 may be referred as a mobile station, a wireless terminal, or the like. In some examples, user equipment 101 may be a cellular phone, a wireless modem, a wireless communication device, a handheld device, a laptop computer or the like. User equipment 101 may also be an loT (internet of things) device, like wireless camera, a smart sensor or smart meter, a vehicle, a global positioning system device, or any other device configured to communicate through a wireless network.

[0061] To mitigate high propagation loss when using millimeter wavelengths as in 5G NR, the base station 102 may implement beamforming techniques to target a specific user equipment like UE 101 . This is illustrated on FIG. 1 with a first set of beams 104 and a second set of beams 105. Based on feedbacks received from US 101 , the base station 102 may select one or more beams directed toward UE 101 for downlink communication. For example, the base station 102 may send downlink data to UE 101 using beam 104a. Beam 104a may be selected based on radio signal characteristics reported by UE 101.

[0062] When there is no data transmission, UE 101 may enter an inactive or idle state to save power.

[0063] If base station 102 has data to transmit to UE 101 while UE is in inactive or idle state, base station 102 may broadcast a paging message. Because the location of the UE 101 is unknown, the paging message needs to be transmitted on all beams within all cells of the RAN (Radio Access Network) notification area (RNA).

[0064] The RAN Notification Area (RNA) comprises one or more cells belonging to one or more base stations. If the last serving 5G BS receives downlink data destinated to a UE, it sends the paging messages to every cell in the RNA. The paging message can also be sent to neighboring base stations belonging to the RNA, through the Xn interface.

[0065] The present disclosure contemplates a selective transmission of the paging message according to which the paging message is transmitted on a subset of cells and / or beams based on cell / beam preferences signaled by the UE before it enters inactive or idle state.

[0066] Main steps of the method for transmitting a paging notification and of the method for receiving a paging notification will now be describer with reference to FIG. 2.

[0067] In a first step 200, a user equipment may determine one or more preferred beams and or preferred cell. The beam preference may be determined by the user equipment according to a mobility status indicating whether the user equipment is stationary, semi-stationary or non-stationary. The user equipment may determine a first number of preferred beams when said mobility status indicates a stationary user equipment, and a second number of preferred beams when said mobility status indicates a non-stationary user equipment, the second number of beams being greater than the first number of beams.

[0068] According to an embodiment, the number of preferred beams for a specific mobility status is configured by a network node beforehand through a configuration message, for example a RRCReconfiguration request. For example, a base station may send a configuration message to instruct a UE to report a first number of preferred beams and / or cells when UE is stationary, a second number of preferred beams and / or cells when UE is semi-stationary, and a third number of preferred beams and / or cells when UE is non-stationary.

[0069] The user equipment may determine beam preference according to its future location. In some examples, the future location of the user equipment may be determined based on its current location or an history of previous locations, a velocity and / or a moving direction.

[0070] The user equipment may periodically update its beam / cell preference.

[0071] During step 201 , the user equipment may report its beam / cell preferences to a base station in a message 202.

[0072] According to an embodiment, the user equipment reports beam / cell preferences by sending a configuration parameter to a base station in said message 202, said configuration parameter including at least said one or more preferred beam determined at step 200. In some embodiments, the message 202 is a UEAssistancelnformation message.

[0073] UE Assistance Information is a special RRC message defined in 3GPP specification TS 38.331 by which a user equipment can inform various internal status to the network. The network may thus adjust resources allocated to said user equipment to better fit its needs. A user equipment may send UEAssistancelnformation message in response to a RRCReconfiguration message or whenever it wants.

[0074] The base station 102 receives the message 202 comprising beam / cell preferences at step 203 and stores the preferences in a context associated with the user equipment.

[0075] The user equipment may enter a RRC Inactive or RRC Idle state at step 204. For example, the user equipment may be instructed by the base station to enter Inactive or Idle state through a RRC Release with SuspendConfig message. While in RRC Inactive or Idle state continue to monitor the paging channel. Note that the base station is aware of the user equipment having entered inactive state, either because user equipment has entered inactive state on request from the base station, or because user equipment has reported its state change through signaling.

[0076] At step 205, the base station may receive data for transmission to the user equipment. If the base station determines that the user equipment is in Inactive or Idle state, the base station may retrieve beams and / or cell preference received from the user equipment during step 203.

[0077] At step 206, the base station prepares and sends a paging notification 207 to the user equipment using beams / cells preference associated with the user equipment. Hence, the paging notification is transmitted only on a subset of beams and / or a subset of cells reported as preferred by the user equipment.

[0078] During step 208, the user equipment receives said paging message 207 while in inactive or idle state. The user equipment may then establish a downlink connection in order to receive incoming data.

[0079] FIG.3 shows a schematic architecture of an apparatus 300 suitable to implement a method for transmitting a paging notification, according to an embodiment.

[0080] The apparatus 300 comprises a processor 301 and a memory 302, for example a Random Access Memory (RAM). The processor 301 may be controlled by a computer program 303 stored in the memory 302 comprising instructions configured to implement a method for transmitting a paging notification, according to an embodiment.

[0081] More precisely, the computer program 303 comprises instructions configured to implement steps of receiving from said user equipment, before said user equipment enters inactive or idle state, a configuration parameter including at least one preferred beam for receiving a transmission, determining a subset of beams based at least on said at least one preferred beam received, and transmitting a paging request to said user equipment over said determined subset of beams.

[0082] On initialization, the computer program instructions 303 may be loaded into the memory 302 before being executed by the processor 301. The processor 301 implements the steps of the method according to the instructions of the computer program 303.

[0083] The apparatus 300 comprises a wireless communication unit 304 configured to exchange data using radio signals. The communication unit 304 may be a 3G, 4G, 5G, NR, WiFi or Wimax transceiver suitable for establishing connections and exchange data with one or more user equipment of a wireless network. The communication unit 304 may be configured to receive from a user equipment a configuration parameter including at least one preferred beam and or one preferred cell for receiving a transmission.

[0084] In some embodiments, the apparatus 400 may also comprise a beam determination unit 305 configured to determine one or more beams or cells suitable for transmitting data to a specific user equipment while the user equipment is in inactive or idle state. According to an embodiment, the beam determination unit may retrieve beam and / or cell preferences received in a UEAssistance Information message received from a user equipment by the communication module 304, and to store the received beam / cells preferences in a database in association with an identifier of the user equipment. The beam determination unit may be implemented by computer program instructions configured to determine a set of preferred beams and / or cells that could be used to send a paging notification to the user equipment when said user equipment is in inactive or idle state.

[0085] According to an embodiment, the communication module 304 is further configured to transmit a paging notification to a user equipment in active or idle state when downlink data is available for transmission to said user equipment, said paging notification being transmitter using a subset of beams and / or cells determined by the beam determination unit 305.

[0086] According to an embodiment, the apparatus 300 is included in a network node, for example a LTE or 5G NR base station.

[0087] FIG.4 shows a schematic architecture of an apparatus 400 suitable to implement a method for receiving a paging notification, according to an embodiment.

[0088] The apparatus 400 comprises a processor 401 and a memory 402, for example a Random Access Memory (RAM). The processor 401 may be controlled by a computer program 403 stored in the memory 402 comprising instructions configured to implement a method for receiving a paging notification, according to an embodiment.

[0089] More precisely, the computer program 403 comprises instructions configured to implement steps of determining one or more preferred beam based at least on user equipment location, transmitting a configuration parameter to said network node before entering idle or inactive state, said configuration parameter including at least said one or more preferred beam, and receiving a paging request while in inactive or idle state from said network node, said paging request being transmitted by said network node on a subset of beams comprising said one or more preferred beam.

[0090] On initialization, the computer program instructions 403 may be loaded into the memory 402 before being executed by the processor 401. The processor 401 implements the steps of the method according to the instructions of the computer program 403.

[0091] The apparatus 400 comprises a wireless communication unit 404 configured to exchange data using radio signals. The communication unit 304 may be a 3G, 4G, 5G, NR, WiFi or Wimax transceiver suitable for establishing connections and exchange data with one or more user equipment of a wireless network, for example, with a base station.

[0092] The apparatus 400 also comprise a beam determination module 405 configured to determine one or more beams or cells suitable for receiving data from a network node while in inactive or idle state. According to an embodiment, the beam determination module is implemented by computer program instructions configured to determine a mobility status of the apparatus 400, and to determine a set of preferred beams and / or cells that could be used by a network node to send a paging notification while the apparatus is in idle or inactive state.

[0093] According to an embodiment, the communication unit 404 may be configured by computer program instructions to receive a configuration message from a network node, said message comprising a number of preferred beams or cells that the apparatus may report to the network node depending on its mobility status. In some embodiments, said configuration parameter may comprise a first number of beams when said mobility status indicates a stationary user equipment, and a second number of beams when said mobility status indicates a non-stationary user equipment, the second number of beams being greater than the first number of beams.

[0094] According to an embodiment, the apparatus 400 comprises a power saving unit 406 configured to switch from a connected mode to an inactive or idle state when no data transfer is expected. The power saving module may be implemented by computer program instructions configured to determine that no downlink data is expected from a network node, (e.g., a command for switching to inactive state may be send by the network node) and / or no uplink data is expected to be sent and to release some radio resources if applicable.

[0095] According to an embodiment, the communication unit 404 is further configured for receiving a paging message from a network node after the power saving unit 406 has switched to inactive or idle state, said paging request being transmitted by said network node on a subset of beams comprising said one or more preferred beam. According to an embodiment, the apparatus is included in a user equipment device, for example in 5G NR compatible smartphone, tablet, connected vehicle, computer or any connected device.

Claims

CLAIMS1. A method of wireless communication by a network node for transmitting a paging notification to a user equipment in inactive or idle state, the method comprising:- Receiving (203) from said user equipment, before said user equipment enters inactive or idle state, a configuration parameter including at least one preferred beam for receiving a transmission,- Determining (205) a subset of beams based at least on said at least one preferred beam received,- Transmitting (206) a paging request (207) to said user equipment over said determined subset of beams.

2. A method according to any of preceding claims wherein said received configuration parameter further comprise a cell preference and wherein said subset of beams is further determined based on said preferred cell.

3. A method according to any of preceding claims wherein said configuration parameter is received in an Assistance Information message.

4. An apparatus for transmitting a paging notification to a user equipment in inactive or idle state in a wireless network, said apparatus comprising a processor (301 ) coupled with a memory (302) in which computer program instructions (303) are stored, and a radio transceiver (304), wherein said processor being configured by said instructions to perform step of:- Receiving from said user equipment, before said user equipment enters inactive or idle state, a configuration parameter including at least one preferred beam for receiving a transmission,- Determining a subset of beams based at least on said at least one preferred beam received,- Transmitting a paging request to said user equipment over said determined subset of beams.

5. A wireless network base station comprising an apparatus according to claim 4.

6. A method of wireless communication by a user equipment device for receiving a paging notification from a network node while in inactive or idle state, the method comprising:- Determining (200) one or more preferred beam based at least on user equipment location,- Transmitting (201 ) a configuration parameter to said network node before entering idle or inactive state, said configuration parameter including at least said one or more preferred beam,- Receiving (208) a paging request (207) while in inactive or idle state from said network node, said paging request being transmitted by said network node on a subset of beams comprising said one or more preferred beam.

7. A method according to claim 6 wherein the method further comprises a step of determining a mobility status of said user equipment, and wherein said configuration parameter comprises:- a first number of beams when said mobility status indicates a stationary user equipment, and- a second number of beams when said mobility status indicates a non-stationary user equipment, the second number of beams being greater than the first number of beams.

8. A method according to any of claims 6 to 7 wherein said configuration parameter further includes a cell preference and wherein said received paging request is transmitted by a network node from a preferred cell.

9. A method according to any of claims 6 to 8 wherein said configuration parameter is transmitted in an Assistance Information message.

10. A method according to claim 9 wherein the determining at least one preferred beam further comprise: determining a future localization of said user equipment, and- Determining a beam configuration corresponding to said future localization.

11. An apparatus for receiving a wireless paging notification from a network node while in inactive or idle state, said apparatus comprising a processor (401 ) coupled with a memory (402) in which computer program instructions (403) are stored, and a radio transceiver (404), wherein said processor being configured by said instructions to perform step of:- Determining one or more preferred beam based at least on user equipment location,- Transmitting a configuration parameter to said network node before entering idle or inactive state, said configuration parameter including at least said one or more preferred beam,- Receiving a paging request while in inactive or idle state from said network node, said paging request being transmitted by said network node on a subset of beams comprising said one or more preferred beam.

12. A user equipment comprising an apparatus according to claim 11.

13. A wireless communication system for transmitting a paging notification to a user equipment, said system comprising a user equipment according to claim 12 and a base station according to claim 5.

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