CN110999395B

CN110999395B - Enhanced radio link monitoring for new radios

Info

Publication number: CN110999395B
Application number: CN201780093740.6A
Authority: CN
Inventors: 李海涛; 张力
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2017-08-10
Filing date: 2017-08-10
Publication date: 2022-07-22
Anticipated expiration: 2037-08-10
Also published as: WO2019028728A1; CN110999395A

Abstract

A method, apparatus and computer program product for a user equipment in a wireless communication network to interactively perform radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station, and determine which to perform for different timing relationships of the beam recovery procedure compared to the radio link monitoring: triggering a re-establishment procedure, instructing the network to switch to the at least one candidate beam, or instructing the network to return the at least one serving beam.

Description

Enhanced radio link monitoring for new radios

Technical Field

The present invention relates generally to wireless communication systems related to multi-antenna technology in New Radios (NRs), and more particularly to an enhanced radio link quality control mechanism for NRs by considering the interaction between radio link monitoring and beam failure recovery procedures.

Background

This section is intended to provide a background or context to the invention that is disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented, or described. Thus, unless otherwise explicitly stated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section.

From an earlier consensus in RAN1, beam management is a set of L1/L2 procedures for acquiring and maintaining a set of TRP and/or UE beams that may be used for DL and UL transmission/reception, including at least the following:

the beam determination is used for the TRP or the UE to select its own Tx/Rx beam. The beam measurement is used for TRP or UE to measure the characteristics of the received beamformed signals. The beam report is information for the UE to beam-form a signal based on the beam measurement report. Beam scanning is an operation of covering a spatial region in which beams are transmitted and/or received in a predetermined manner within a certain time interval.

The UE beam failure recovery mechanism includes beam failure detection, new candidate beam identification, beam failure recovery request transmission, and UE monitoring for a gNB response to the beam failure recovery request.

Radio Link Monitoring (RLM), on the other hand, is an L3 procedure already used in LTE, as specified in section 5.3.11 of 36.331. RLM in NR is very similar to LTE.

The present invention goes beyond these techniques.

Abbreviations that may be found in the specification and/or the drawings are defined in the text or in the following list of abbreviations:

2G: second generation

3G: third generation

3 GPP: third generation partnership project

5G: fifth generation

5G-NB: fifth generation node B

And ACK: confirmed/confirmed

A/N: confirmed/not confirmed

ARQ: automatic repeat request

BCI: beam change indication

BS: base station

BSI: beam state information

BRI: beam refinement information

And (3) BRS: beam reference signal

And (3) BRRS: beam refinement reference signal

BSR: buffer status reporting

CB: contention-based

CE: control element

CQI: channel quality indicator

CSI: channel state information

C-RNTI: cell radio network temporary identifier

DCI: downlink control information

DL: downlink link

eNB or eNodeB: evolved node B (LTE base station)

EPDCCH: enhanced physical downlink control channel

E-UTRAN: evolved UTRAN

And g NB: NR/5G node B

HARQ: hybrid automatic repeat request

IS: synchronization

L1: physical layer or PHY

L2: MAC/RLC/PDCP layer

L3: RRC layer

LCID: logical channel identifier

LTE: long term evolution

And (3) LTE-A: long term evolution advanced

And (3) LTE-M: LTE system nodeb (nb) supporting MTC or M2M: node B (base station in UTRAN) MAC: media access control

MAC CE: MAC control element

MIMO: multiple input multiple output

MTC: machine type communication

NACK: unacknowledged/negative acknowledgement

NB: NodeB and base station

NR: new radio

OOS: asynchronous

PDCP: packet data convergence protocol

PDSCH: physical downlink shared channel

PDCCH: physical downlink control channel

PDU: protocol data unit

PHR: power headroom reporting

PRACH: physical random access channel

PRB: physical resource block

PUCCH: physical uplink control channel

PUSCH: physical uplink shared channel

QoS: quality of service

RACH: random access channel

RAN: radio access network

RAT: radio access technology

RBI: refining beam index

RRC: radio resource control

RE: resource elements

Rel: version(s)

ReTx: retransmission (retransmission) or retransmission (retransmission)

RLC: radio link control

RLF: radio link failure

RLM: radio link monitoring

RSRP: reference signal received power

RSRQ: reference signal reception quality

RSSI: received signal strength indicator

Rx, RX: receiving or receiving

SB: cleaning block

SPS: semi-persistent scheduling

SR: scheduling requests

SRS: sounding reference signal

TDD: time division duplex

A TRP: transmitting-receiving point

And TS: technical specification or standard

TTI: transmission time interval

Tx, TX: transmission or Transmission

TXRU: transceiver unit

UCI: uplink control information

UE: user equipment or mobile station

UL: uplink link

UL-SCH: uplink shared channel

PUSCH: physical uplink shared channel

Disclosure of Invention

This section is intended to include examples, and is not intended to be limiting. As discussed in detail below, the present invention proposes an enhanced radio link quality control mechanism for NR by considering the interaction between the RLM and the beam failure recovery procedure.

An example of an embodiment of the present invention is a method comprising interactively performing by a user equipment in a wireless communication network radio link monitoring of at least one serving beam from a serving base station and a beam recovery procedure of at least one candidate beam from the serving base station; and determining, by the user equipment in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, instructing, by the user equipment, the network to switch to the at least one candidate beam, and instructing, by the user equipment, the network to return to the at least one serving beam.

An example of another embodiment of the present invention is an apparatus comprising at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform at least the following: interactively performing, by a user equipment in a wireless communication network, radio link monitoring of at least one serving beam from a serving base station and a beam recovery procedure of at least one candidate beam from the serving base station; and determining, by the user equipment in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, instructing, by the user equipment, the network to switch to the at least one candidate beam, and instructing, by the user equipment, the network to return to the at least one serving beam.

An example of another embodiment of the invention is a computer program product embodied on a non-transitory computer readable medium having a computer program stored therein, the computer program, when executed by a computer, being configured to provide instructions for controlling or performing at least the following: interactively performing, by a user equipment in a wireless communication network, radio link monitoring of at least one serving beam from a serving base station and a beam recovery procedure of at least one candidate beam from the serving base station; and determining, by the user equipment in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, instructing, by the user equipment, the network to switch to the at least one candidate beam, and instructing, by the user equipment, the network to return to the at least one serving beam.

An example of yet another embodiment of the invention disclosed herein is an apparatus comprising: means for interactively performing, by a user equipment in a wireless communication network, radio link monitoring of at least one serving beam from a serving base station and a beam recovery procedure for at least one candidate beam from the serving base station; and means for determining, by the user equipment in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, instructing, by the user equipment, the network to switch to the at least one candidate beam, and instructing, by the user equipment, the network to return to the at least one serving beam.

Drawings

In the drawings:

FIG. 1 is a block diagram of one possible and non-limiting exemplary system in which exemplary embodiments may be practiced;

fig. 2 shows a time relationship in which the beam recovery procedure continues after expiration of a timer for allowing the user equipment to reacquire synchronization with the serving base station;

fig. 3 shows a time relationship in which a beam recovery procedure is completed before expiration of a timer for allowing a user equipment to reacquire synchronization with a serving base station; and

fig. 4 is a logic flow diagram for enhanced radio link monitoring of a new radio and illustrates operations of an exemplary method, execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and/or an interconnect means for performing functions in accordance with exemplary embodiments.

Detailed Description

The present invention relates generally to wireless communication systems associated with release 15WI "New Radio (NR) access technology". Unlike LTE, in NR systems, multi-beam operation supported by multi-antenna technology is introduced for DL and UL transmission/reception. The 3GPP is still discussing beam management procedures that support beam level mobility, and the beam failure recovery procedure is considered part of beam management.

RAN2NR conference ad 6, 2017 agreed that beam failure recovery (L1 or MAC) and rlf (rrc) were performed in different layers in RAN 2.

Some RAN2 contributions submitted to the most recent conference are discussed herein. In R2-1706437 it is proposed that if the beam failure recovery is not successful, RLF is declared and different options are listed for interactive modeling, e.g. beam failure recovery with or without RRC involvement. It is proposed in R2-1706680 that upon failure of the beam failure recovery mechanism for each beam subset, the UE should provide a radio link failure indication to layer 2 to facilitate mobility without RRC involvement. It is proposed in R2-1706745 that for multi-beam operation, RLF is declared after beam recovery failure of all UL beams via the serving cell. It is proposed in R2-1706965 that during synchronous/asynchronous detection in RLF, the RLF timer can be stopped or suspended if beam failure recovery is triggered.

Existing work in this area does not provide a comprehensive solution to address all timing relationships between the RLM and beam failure recovery procedures considered in the present invention. Although some existing proposals consider that failure of the beam failure recovery procedure triggers RLF, none of them takes the reverse into account, i.e. the RLM procedure should also affect the beam failure recovery procedure as we propose in the present invention.

The problem addressed in the present invention is the interaction between the RLM and the beam failure recovery procedure, more specifically the UE behavior when the beam failure recovery procedure is ongoing during the T310 timer running. The T310 timer is an LTE nomenclature of a timer that is started when an RRC connection re-establishment procedure is initiated and stopped when a suitable E-UTRA cell or a cell using other RATs is selected. Upon expiration, it will enter the RRC IDLE state. Note that T310 and N311 (also discussed herein) are parameters used in the LTE system. The intention of the invention is to reuse the RLM mechanism of LTE, but this does not necessarily mean that future specifications in NR will reuse the same parameter names. Thus, the present invention utilizes these as general concepts when describing these two parameters, and is not necessarily limited to the same measurement. Thus, since the new radio may use a different nomenclature and the term T310 is used herein for convenience. Likewise, N311 is also LTE nomenclature and is also used herein for convenience. In general, N311 denotes a plurality of consecutive synchronizations allowing the user equipment to confirm synchronization with the serving base station,

in LTE, to determine whether the radio link is asynchronous, the N310 parameter indicates the number of 200ms intervals when the UE cannot successfully decode the PDCCH due to a detected low RSRP. N310 indicates the number of times the UE fails to successfully decode 20 consecutive frames in the downlink. T310 is a timer (in seconds) for allowing the UE to return synchronization with the eNodeB. N311 is a parameter indicating the number of 100ms intervals that the UE must successfully decode the PDCCH to return synchronization with the eNodeB. That is, the parameter indicates the number of times the UE must successfully decode 10 consecutive frames in the downlink in order for the UE to assume that the radio link is synchronized. In LTE, if the UE detects a N310 continuous asynchronous indication, it will start a T310 timer. If the timer expires, the link fails. If the UE detects N311 consecutive synchronization indications before the T310 timer expires, the timer will stop and the link will not fail.

In the NR system, the UE performs radio link monitoring on the serving beam and the process proceeds in a similar manner to LTE, i.e. the physical layer generates periodic synchronous or asynchronous indications to the RRC layer and based on these indications the RRC layer decides how to control the timer T310 and whether to declare RLF.

Meanwhile, even if the beam management procedures (still in the RAN1 discussion) are intended to handle beam level mobility well, the RAN1 is considering beam failure recovery procedures to handle special cases, such as sudden channel degradation due to blocking or beam misalignment due to fast channel changes, which are beyond the capabilities of the beam management procedures. Thus, the UE may recover the failed beam on the new candidate beam (or on the previous beam, depending on the UE's mobility), and all subsequent transmissions may switch to the recovered beam.

In this regard, the impact on the radio link monitoring procedure is not negligible, and the interaction between the RLM and the beam failure recovery procedure is not trivial. For example, the UE behavior should be defined in terms of whether the UE should continue radio link monitoring on the current beam until RLF occurs during the beam failure recovery procedure and whether the beam recovery failure should directly trigger RLF. The present invention addresses these problems.

Turning to FIG. 1, prior to turning to a further discussion of the present invention, FIG. 1 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced.

Note that the word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in the detailed description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

In fig. 1, a User Equipment (UE)110 is in wireless communication with a wireless network 100. A UE is a wireless, typically mobile, device that can access a wireless network. UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, an optical fiber, or other optical communication device, and so forth. One or more transceivers 130 are connected to the one or more antennas 128. The one or more memories 125 include computer program code 123. Note that the YYY module allows functionality for data transfer using control resources in which any of the methods discussed herein or examples of such embodiments may be practiced. UE 110 includes YYY module 140, and YYY module 140 includes one or both of portions 140-1 and/or 140-2, which may be implemented in a variety of ways. YYY module 140 may be implemented in hardware as YYY module 140-1, such as part of one or more processors 120. The YYY module 140-1 may also be implemented as an integrated circuit or by other hardware, such as a programmable gate array. In another example, the YYY module 140 may be implemented as YYY module 140-2, the YYY module 140-2 being implemented as computer program code 123 and being executed by the one or more processors 120. For example, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more operations as described herein. UE 110 communicates with gNB 170 via radio link 111.

The gNB (new radio 5G NodeB, to be denoted as gNB or possibly some variant of an evolved NodeB) 170 is a base station (e.g., for LTE long term evolution or 5G base station) that provides access to the wireless network 100 through a wireless device, such as UE 110. The gNB 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/WI/F)161, and one or more transceivers 160 interconnected by one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. One or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. Note that the ZZZ module allows the functionality of data transmission using control resources, in which any of the methods discussed herein or examples of such embodiments may be practiced. The gNB 170 includes a ZZZ module 150, the ZZZ module 150 including one or both of the portions 150-1 and/or 150-2, which may be implemented in a variety of ways. The ZZZ module 150 may be implemented in hardware as a ZZZ module 150-1, such as part of one or more processors 152. The ZZZ module 150-1 may also be implemented as an integrated circuit or by other hardware, such as a programmable gate array. In another example, the ZZZ module 150 may be implemented as a ZZZ module 150-2, the ZZZ module 150-2 being implemented as computer program code 153 and being executed by the one or more processors 152. For example, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the gNB 170 to perform one or more operations as described herein. One or more network interfaces 161 communicate over a network, such as via links 176 and 131. Two or more gnbs 170 communicate using, for example, link 176. The link 176 may be wired or wireless or both and may implement, for example, an X2 interface.

The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, optical or other optical communication devices, wireless channels, etc. For example, the one or more transceivers 160 can be implemented as Remote Radio Heads (RRHs) 195, wherein other elements of the gNB 170 are physically located at a different location than the RRHs, and the one or more buses 157 can be partially implemented as fiber optic cables to connect the other elements of the gNB 170 to the RRHs 195.

Note that the description herein indicates that "cell" performs the function, but it should be clear that the gnbs forming the cell will perform the function. The cells form part of the gbb. That is, there may be multiple cells per gNB. For example, for a single gNB carrier frequency and associated bandwidth, there may be three cells, each covering one third of the 360 degree area, such that the coverage area of a single gNB covers approximately an oval or circle. Further, each cell may correspond to a single carrier, and the gNB may use multiple carriers. Thus, if there are three 120 degree cells per carrier and there are two carriers, then there are 6 cells in total for the gNB.

The wireless network 100 may include a Network Control Element (NCE)190, and the NCE 190 may include MME (mobility management entity)/SGW (serving gateway) functionality and provide connectivity to additional networks such as a telephony network and/or a data communications network (e.g., the internet). The gNB 170 is coupled to NCE 190 via link 131. Link 131 can be implemented as, for example, an S1 interface. NCE 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/WI/F)180 interconnected by one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the NCE 190 to perform one or more operations.

Wireless network 100 may implement network virtualization, which is a process that combines hardware and software network resources and network functions into a single software-based management entity, a virtual network. Network virtualization involves platform virtualization, often in combination with resource virtualization. Network virtualization is classified as external (combining many networks or parts of networks into virtual units) or internal (providing network-like functionality for software containers on a single system). Note that the virtualized entities resulting from network virtualization may still be implemented to some extent using hardware such as the

processor

152 or 175 and the

memories

155 and 171, and such virtualized entities also produce technical effects.

The computer-

readable memories

125, 155, and 171 may be of any type suitable to the local technical environment, and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer-

readable memories

125, 155 and 171 may be means for performing a storage function. The

processors

120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.

Processors

120, 152, and 175 may be means for performing functions, such as controlling UE 110, gNB 170, and other functions described herein.

In general, the various embodiments of the user device 110 can include, but are not limited to, cellular telephones, such as smart devices, tablets, Personal Digital Assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, internet appliances permitting wireless internet access and browsing, tablets having wireless communication capabilities, and portable units or terminals that incorporate combinations of such functions. In addition, various embodiments of the user device include machine, communicator, and device classes that are not substantially or not at all used for human interaction.

The current architecture in LTE networks is fully dispersed in the radio and fully centralized in the core network. Low latency requirements bring the content close to the radio, which can lead to local explosion and multiple access edge computation (MEC). 5G may use edge cloud and local cloud architectures. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer ad hoc networks and processes, and can also be classified as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, and augmented reality. In radio communications, using an edge cloud may mean that node operations are to be performed at least in part in a server, host, or node operatively coupled to a remote radio head or base station that includes a radio portion. Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be understood that the labor allocation between core network operation and base station operation may be different than that of LTE, or even non-existent. Some other technological advances that may be used are Software Defined Networking (SDN), big data, and all IP, which may change the way the network is built and managed.

One possible way to implement the embodiments described herein is to utilize an edge cloud using a distributed computing system. An exemplary embodiment includes a radio node connected to a server. Example embodiments implementing the system allow the edge cloud server and the radio node to be independent devices communicating with each other via a radio path or via a wired connection, or they may be located in the same entity communicating via a wired connection.

The present invention proposes an enhanced radio link quality control mechanism for NR by considering the interaction between RLM and beam failure recovery procedures, and in particular teaches what should be done if the beam recovery procedure is still in progress when T310 expires/stops and what should be done if the beam recovery procedure is done when T310 is still running.

If the beam recovery procedure is still in progress at the expiration/stop of T310, the UE does not trigger RLF, but rather continues RLM in the serving beam.

If N311 continuous synchronization is received on the serving beam before the beam recovery procedure is completed, the UE aborts the ongoing beam recovery procedure and the UE indicates "return to serving beam" to the gNB, e.g., by reusing beam recovery request signaling.

If the beam recovery procedure IS complete and N311 continuous synchronization has not been received on the serving beam, then if the beam recovery IS successful, the UE switches to the new beam, resets all previous IS/OOS counters, restarts T310 and performs RLM on the new beam.

If the beam recovery procedure is complete and N311 consecutive syncs have not been received on the serving beam, then if the beam recovery fails, the UE indicates to L3 and declares RLF.

If the beam recovery procedure IS complete and the beam recovery IS successful while T310 IS still running, the UE switches to the new beam, resets all previous IS/OOS counters, restarts T310, and performs RLM on the new beam. However, if the beam recovery procedure is completed but the beam recovery fails while T310 is still running, the UE continues to perform RLM on the serving beam as if the beam recovery procedure has not been performed.

Fig. 2 presents a block diagram of the case where the beam recovery procedure is still in progress at the expiration of T310.

Item 202 represents a service beam and item 204 represents a candidate beam along the same time frame. In the service beam 202, the beam represented by item 206 has RLM being performed, but due to good link quality, T310 has not yet started. During the time interval represented by item 208, T310 is running and no consecutive N311 synchronizations have been received on the serving beam. The point in time represented by item 212 is the time at which T310 expires. The RLM continues on the serving beam for the time frame of item 210. If N311 continuous synchronization is received on the serving beam before the beam recovery procedure is completed, the UE aborts the ongoing beam recovery procedure and indicates "return to serving beam" to the gNB, e.g., by reusing beam recovery request signaling.

In the candidate beam 204, if so configured, the beam travels as usual in item 214 with only some RRM measurements, but within the time interval represented by item 216, the beam recovery process occurs. The beam recovery process ends at the time marked by item 220.

During the time interval represented by item 218, depending on the outcome of the beam recovery process: if successful, the candidate beam becomes the serving beam and RLM is performed; alternatively, T310 may be initiated; if it fails, nothing happens on the candidate beam, only some RRM measurements (if so configured).

The rationale for not triggering RLF at the expiration of T310 is that the beam recovery procedure is in progress and the UE still has an opportunity to recover the link on the candidate beam.

Continuing RLM on the serving beam while waiting for beam recovery has the benefit of potential recovery on the serving beam by collecting N311 consecutive synchronizations (e.g., to increase robustness in case the UE moves back to the serving beam).

If the UE "recovers" the serving beam, meaning that the serving beam can be used for transmission again reliably, no further beam recovery attempts are needed, and therefore the UE should abort the ongoing beam recovery procedure and inform the gNB of this fact, since the gNB has not yet realized this and is still doing beam recovery. The indication may be sent on the serving beam by similar signaling of a reuse beam recovery request. When the gNB receives this indication, it knows that beam recovery on the candidate beam can be stopped and that the UE has returned to the serving beam.

Otherwise, if "recovery" is not achieved on the serving beam before the beam failure recovery procedure is completed, the UE behavior depends on the outcome of the beam recovery procedure.

If the beam recovery is successful, it means that the new candidate beam can be reliably used for transmission and therefore the UE should switch to the new beam. To have more robust control over the new beam, the UE may choose to start T310 and see if N311 consecutive synchronizations can be collected on the new beam. From the RLM perspective, this can be seen as a double check.

If the beam recovery fails, it means that neither the serving beam nor the candidate beam is reliable. In this case, L3 should be notified and RLF triggered.

Fig. 3 presents a block diagram of the case where the beam recovery process is completed while T310 is still running.

Again, the service beam represented by item 302 and the candidate beam represented by item 304 are processed in the same time domain. In the serving beam 302, RLM is performed during time interval 306, but T310 is not started due to good link quality, then T310 runs during interval 308, ends at the time marked by item 312, and after T310 runs are completed, the beam continues during interval 310, depending on the outcome of the beam failure recovery procedure and RLM of the serving beam.

If so configured, the candidate beam 304 continues during time interval 314 with only some RRM measurements. During time interval 316, the beam recovery process is ongoing. After beam recovery is complete (represented by item 320), the candidate beam proceeds as previously described (represented by item 318), depending on the outcome of the beam failure recovery process: if successful, the candidate beam will become the serving beam and RLM is performed, optionally T310 may be initiated; if it fails, nothing happens on the candidate beam, only some RRM measurements (if so configured).

If the beam recovery is successful, the UE switches to a new beam that can be reliably used for transmission. For more robust link control, the UE may choose to start T310 and evaluate whether N311 consecutive synchronizations can be collected on the new beam.

If the beam recovery fails, the RAN1 has agreed that the UE is not to make further beam recovery attempts, and the UE simply waits for the result of the RLM on the serving beam, i.e., the T310 timer expires.

Embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., application specific integrated circuits), or a combination of software and hardware. In an example of an embodiment, the software (e.g., application logic, a set of instructions) is maintained on any one of a variety of conventional computer-readable media. In the context of this document, a "computer-readable medium" can be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer being described and depicted, for example, in FIG. 1. A computer-readable medium may include a computer-readable storage medium (e.g., 104, 134 or other device) that may be any medium or means that can contain, store, and/or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. Computer-readable storage media include not only propagated signals.

Fig. 4 is a logic flow diagram for enhanced radio link monitoring of a new radio and illustrates operations of an exemplary method 400, execution of computer program instructions embodied on a computer readable memory, functions performed by logic embodied in hardware, and/or an interconnect means for performing functions in accordance with exemplary embodiments. Some or all of exemplary method 400 may be performed in block YYY or block ZZZ, as appropriate. This method mainly occurs at the UE side in terms of timer processing and RLM. Reporting back to the serving beam to the gbb also affects the gbb.

The exemplary method 400 includes: a step 402, in which the UE interactively performs a radio link monitoring on at least one serving beam from the serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and a step 404 in which the UE determines what to perform in response to the beam recovery procedure and radio link monitoring having different timing relationships. Item 406 shows that the input to this determination is a time relationship such that the beam recovery process continues after or completes before the timer expires. Another input is an entry 408 as to whether the beam recovery was successful or failed. Other inputs not shown include such things as whether the UE can confirm synchronization with the serving base station. Based on the determination, the UE may perform a trigger re-establishment procedure 410, indicate to the network that the UE is switching to the candidate beam 412, and indicate to the network that the UE is returning to the serving beam 414.

If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Further, if desired, one or more of the above-described functions may be optional or may be combined.

Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, advantages or technical effects of one or more of the example embodiments disclosed herein of the proposed radio link quality control mechanism are: it provides a comprehensive solution for all timing relationships between RLM and beam failure recovery procedures.

Furthermore, without in any way limiting the scope, interpretation, or application of the claims appearing below, the advantages or technical effect of one or more of the example embodiments disclosed herein of the proposed interaction scheme are: the probability of successful recovery of the link on the serving/candidate beam may be improved and unnecessary RLF may be avoided.

Furthermore, without in any way limiting the scope, interpretation, or application of the claims appearing below, the advantages or technical effects of one or more of the example embodiments disclosed herein of the proposed interaction scheme, compared to previous work in the art, are: RLF is not triggered at the expiration of T310 as shown in fig. 2, or at the completion of the beam failure recovery procedure as shown in fig. 3, indicating a greater chance of link recovery.

Additionally, without in any way limiting the scope, interpretation, or application of the claims appearing below, the advantages or technical effects of one or more of the example embodiments disclosed herein of the proposed interaction scheme are: unnecessary beam failure recovery can be avoided.

Furthermore, without in any way limiting the scope, interpretation, or application of the claims appearing below, the advantages or technical effects of one or more of the example embodiments disclosed herein of the proposed interaction scheme, compared to previous work in the art, are: if the serving beam is recovered (an N311 sync indication is received), the beam failure recovery procedure will abort and thus the associated signaling overhead can be saved.

An example of an embodiment of the invention that may be referred to as item 1 is a method comprising: interactively performing, by a user equipment in a wireless communication network, a radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and determining, by the user equipment in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, indicating to the network that the user equipment switches to at least one candidate beam, and indicating to the network that the user equipment returns to at least one serving beam.

An example of another embodiment of the present invention that may be referred to as item 2 is the method of item 1, wherein the timing relationship comprises: the beam recovery procedure continues after expiration of a timer for allowing the user equipment to reacquire synchronization with the serving base station.

An example of another embodiment of the present invention that may be referred to as item 3 is the method of item 2, further comprising: continuing the radio link monitoring by the user equipment in the at least one serving beam and not triggering a radio link failure.

An example of another embodiment of the present invention, which may be referred to as item 4, is the method of item 3 wherein the user equipment is allowed to confirm that multiple consecutive synchronizations of synchronization with the serving base station are received on the at least one serving beam before the beam recovery procedure is completed.

An example of another embodiment of the present invention that may be referred to as item 5 is the method of item 4, further comprising: aborting, by the user equipment, the beam recovery procedure, and indicating, by the user equipment, to the serving base station, a return to the at least one serving beam.

An example of another embodiment of the present invention, which may be referred to as item 6, is the method of item 3 wherein the beam recovery procedure is complete and allows the user equipment to confirm that a plurality of consecutive synchronizations of the synchronization with the serving base station have not been received on the at least one serving beam.

An example of another embodiment of the present invention that may be referred to as item 7 is the method of item 6, wherein if the beam recovery is successful, the method further comprises: switching, by the user equipment, to the at least one candidate beam; resetting all previous synchronous/asynchronous counters; and restarting the timer.

An example of another embodiment of the present invention that may be referred to as item 8 is the method of item 6, wherein if the beam recovery fails, the method further comprises: indicating, by the user equipment, to a radio resource control protocol layer and declaring a radio link failure.

An example of another embodiment of the present invention that may be referred to as item 9 is the method of item 1, wherein the timing relationship comprises: the beam recovery procedure is completed before expiration of a timer for allowing the user equipment to reacquire synchronization with the serving base station.

An example of another embodiment of the present invention that may be referred to as item 10 is the method of item 9, wherein if the beam recovery is successful, the method further comprises: switching, by the user equipment, to the at least one candidate beam; resetting all previous synchronous/asynchronous counters; and restarting the timer.

An example of another embodiment of the present invention that may be referred to as item 11 is the method of item 9, wherein if beam recovery fails, the method further comprises: continuing, by the user equipment, the radio link monitoring on the at least one serving beam as if a beam recovery procedure has not been performed.

An example of another embodiment of the present invention that may be referred to as item 12 is an apparatus comprising at least one processor and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform at least the following: interactively performing in a wireless communication network a radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and determining, in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, indicating to the network to switch to at least one candidate beam, and indicating to the network to return to at least one serving beam.

An example of yet another embodiment of the present invention that may be referred to as item 13 is an apparatus according to item 12, wherein the timing relationship comprises: the beam recovery procedure continues after expiration of a timer for allowing the user equipment to reacquire synchronization with the serving base station.

An example of yet another embodiment of the invention, which may be referred to as item 14, is the apparatus of item 13, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: continuing the radio link monitoring by the user equipment in the at least one serving beam and not triggering a radio link failure.

An example of yet another embodiment of the present invention, which may be referred to as item 15, is the apparatus of item 14 wherein the user equipment is allowed to confirm that multiple consecutive synchronizations of synchronizations with the serving base station are received on the at least one serving beam before the beam recovery procedure is completed.

An example of a further embodiment of the present invention, which may be referred to as item 16, is an apparatus according to item 15, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: aborting, by the user equipment, the beam recovery procedure and indicating, by the user equipment, to the serving base station, a return to the at least one serving beam.

An example of yet another embodiment of the present invention, which may be referred to as item 17, is the apparatus of item 14 wherein the beam recovery procedure is complete and allows the user equipment to confirm that multiple consecutive synchronizations of synchronization with the serving base station have not been received on the at least one serving beam.

An example of a further embodiment of the present invention, which may be referred to as item 18, is an apparatus according to item wherein if beam recovery is successful, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: switching, by the user equipment, to the at least one candidate beam; resetting all previous synchronous/asynchronous counters; and restarting the timer.

An example of yet another embodiment of the present invention, which may be referred to as item 19, is the apparatus of item 17, wherein if beam recovery fails, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: indicating, by the user equipment, to a radio resource control protocol layer and declaring a radio link failure.

An example of a further embodiment of the present invention that may be referred to as item 20 is an apparatus according to item 12, wherein the timing relationship comprises: the beam recovery procedure is completed before expiration of a timer for allowing the user equipment to reacquire synchronization with the serving base station.

An example of another embodiment of the present invention that may be referred to as item 21 is the apparatus of item 20, wherein if beam recovery is successful, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: switching, by the user equipment, to the at least one candidate beam; resetting all previous synchronous/asynchronous counters; and restarting the timer.

An example of another embodiment of the present invention that may be referred to as item 22 is the apparatus of item 20, wherein if beam recovery fails, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: continuing, by the user equipment, the radio link monitoring on the at least one serving beam as if a beam recovery procedure has not been performed.

An example of an additional embodiment of the present invention that may be referred to as item 23 is a computer program comprising: code for interactively performing, by a user equipment in a wireless communication network, radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and code for determining, by the user equipment in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, indicating to the network that the user equipment switches to at least one candidate beam, and indicating to the network that the user equipment returns to at least one serving beam.

An example of another additional embodiment of the present invention, which may be referred to as item 24, is a computer program product embodied on a non-transitory computer readable medium having a computer program stored therein, which when executed by a computer is configured to provide instructions for controlling or performing the method of any of items 1 to 11.

An example of yet another embodiment of the present invention that may be referred to as item 25 is an apparatus comprising: means for interactively performing radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station in a wireless communication network; and means for determining, in response to the beam recovery procedure and the radio link monitoring having different timing relationships, to perform one of: triggering a re-establishment procedure, indicating to the network to switch to at least one candidate beam, and indicating to the network to return to at least one serving beam.

If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined.

It is also noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A method for communication, comprising:

interactively performing, by a user equipment in a wireless communication network, radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and

instructing, by the user equipment, the user equipment to return to at least one serving beam to the network in response to the beam recovery procedure continuing after expiration of a timer for allowing the user equipment to reacquire synchronization with the serving base station; or alternatively

Triggering, by the user equipment, a re-establishment procedure or instructing the user equipment to switch to at least one candidate beam to the network in response to completion of the beam recovery procedure prior to expiration of the timer.

2. The method of claim 1, further comprising: continuing the radio link monitoring by the user equipment in the at least one serving beam and not triggering a radio link failure.

3. The method of claim 2, wherein the user equipment is allowed to confirm that multiple consecutive synchronizations of synchronization with the serving base station are received on the at least one serving beam before the beam recovery procedure is completed.

4. The method of claim 3, further comprising: aborting, by the user equipment, the beam recovery procedure, and indicating, by the user equipment, a return to the at least one serving beam to the serving base station.

5. The method of claim 2, wherein the beam recovery procedure is complete and allows the user equipment to confirm that a plurality of consecutive synchronizations of synchronization with the serving base station have not been received on the at least one serving beam.

6. The method of claim 5, wherein if beam recovery is successful, the method further comprises:

switching, by the user equipment, to the at least one candidate beam;

resetting all previous synchronous/asynchronous counters; and

restarting the timer.

7. The method of claim 5, wherein if beam recovery fails, the method further comprises:

indicating by the user equipment to a radio resource control protocol layer and declaring a radio link failure.

8. The method of claim 1, wherein if beam recovery is successful, the method further comprises:

switching, by the user equipment, to the at least one candidate beam;

resetting all previous synchronous/asynchronous counters; and

restarting the timer.

9. The method of claim 1, wherein if beam recovery fails, the method further comprises:

continuing, by the user equipment, the radio link monitoring on the at least one serving beam as if a beam recovery procedure has not been performed.

10. An apparatus for communication, comprising:

at least one processor; and

at least one memory including computer program code,

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

in a wireless communication network, interactively performing a radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and

instructing the apparatus to return to at least one serving beam to the network in response to the beam recovery procedure continuing after expiration of a timer for allowing the apparatus to reacquire synchronization with the serving base station; or

Triggering a re-establishment procedure or instructing the network to switch the apparatus to at least one candidate beam in response to completion of the beam recovery procedure prior to expiration of the timer.

11. The apparatus of claim 10, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: continuing, by the apparatus, the radio link monitoring in the at least one serving beam and not triggering a radio link failure.

12. The apparatus of claim 11, wherein the apparatus is permitted to confirm that multiple consecutive synchronizations of synchronization with the serving base station are received on the at least one serving beam before the beam recovery process is completed.

13. The apparatus of claim 12, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following: aborting, by the apparatus, the beam recovery procedure, and indicating, by the apparatus, to the serving base station, a return to the at least one serving beam.

14. The apparatus of claim 11, wherein the beam recovery procedure is complete and allows the apparatus to confirm that multiple consecutive synchronizations of synchronization with the serving base station have not been received on the at least one serving beam.

15. The apparatus according to claim 14, wherein if beam recovery is successful, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to perform:

switching, by the apparatus, to the at least one candidate beam;

resetting all previous synchronous/asynchronous counters; and

restarting the timer.

16. The apparatus of claim 14, wherein if beam recovery fails, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following:

indicating, by the apparatus, to a radio resource control protocol layer and declaring a radio link failure.

17. The apparatus of claim 10, wherein if beam recovery is successful, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform at least the following:

switching, by the apparatus, to the at least one candidate beam;

resetting all previous synchronous/asynchronous counters; and

restarting the timer.

18. The apparatus according to claim 10, wherein if beam recovery fails, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to:

continuing, by the apparatus, the radio link monitoring on the at least one serving beam as if a beam recovery procedure has not been performed.

19. A non-transitory computer readable medium having stored therein a computer program which, when executed by a computer, is configured to provide instructions for controlling or implementing a method according to any one of claims 1 to 9.

20. An apparatus for communication, comprising:

means for interactively performing, in a wireless communication network, radio link monitoring on at least one serving beam from a serving base station and a beam recovery procedure on at least one candidate beam from the serving base station; and

means for indicating to the network that the apparatus is returning to at least one serving beam in response to the beam recovery procedure continuing after expiration of a timer for allowing the apparatus to reacquire synchronization with the serving base station; or

Means for triggering a re-establishment procedure or instructing the network to switch the apparatus to at least one candidate beam in response to completion of the beam recovery procedure prior to expiration of the timer.