WO2021077372A1

WO2021077372A1 - Method and access network node for beam management

Info

Publication number: WO2021077372A1
Application number: PCT/CN2019/113094
Authority: WO
Inventors: Qi Zhang; Chunhui Liu; Yuan Dong
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2021-04-29

Abstract

A method and an access network node are disclosed for beam management. According to an embodiment, the access network node detects a first event in which a physical downlink control channel (PDCCH) carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. The access network node obtains, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. The access network node updates a beam management configuration for the terminal device, based on the beam management report.

Description

METHOD AND ACCESS NETWORK NODE FOR BEAM MANAGEMENT

Technical Field

Embodiments of the disclosure generally relate to wireless communication, and, more particularly, to a method and an access network node for beam management.

Background

This section introduces aspects that may facilitate better understanding of the present disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

From analog through long term evolution (LTE) , each generation of mobile technology has been motivated by the need to address the challenges not overcome by its predecessor. The 5th generation (5G) of mobile technology is positioned to address the demands and business beyond LTE. It is expected to enable a fully mobile and connected society, related to the tremendous growth in connectivity and density/volume of traffic that will be required in the near future.

As next-generation cellular networks will use higher frequencies, narrow beam transmission and reception schemes will be needed to compensate for the high propagation loss. This calls for a set of mechanisms by which user equipment (UE) and next generation node base (gNB) stations establish highly directional transmission links, typically using beams formed by high-dimensional phased arrays, to benefit from the resulting beamforming gain and sustain an acceptable communication quality. Directional links, however, require fine alignment of the transmitter and receiver beams, achieved through a set of operations known as beam management. They are fundamental to perform a variety of control tasks including initial access for idle users, which allows a mobile UE to establish a physical link connection with a gNB, and beam tracking for connected users, which enable beam adaptation schemes, or handover, path selection and radio link failure recovery procedures.

In previous cellular generations, UE had to monitor radio signals from neighboring radio cells to facilitate potential switch of the serving cell. When the radio signals are limited to narrow beams, a different approach is needed. The 3rd generation partnership project (3GPP) is working on the new procedures for beam tracking/refinement at the gNB side caused by, e.g., UE movement (P-2) , or tracking/refinement of UE beams that is needed, e.g., due to UE rotation (P-3) . Further on, instead of reporting measurements for the best cells, UE will report measurements for a number of best beams that were detected. The UE may report the reference signal receiving power (RSRP) of potential beam candidates.

Although not explicitly stated in the technical specification of 3GPP, beam management can be divided into to three procedures. The first procedure is initial beam selection (called P-1) where a wide transmission reception point (TRP) transmission (Tx) beam is initially selected. The second procedure is TRP Tx beam refinement (called P-2) where gNB determines its Tx beam according to UE’s report. The third procedure is UE reception (Rx) beam refinement (P-3) where UE Rx beam is determined when TRP Tx beam is selected.

If a beam failure occurs, i.e. if the radio link over the selected gNB beam and the selected UE beam is broken, a recovery procedure is employed to bring the radio link back to an operational status. When a beam failure is detected, a contention-free random-access procedure is triggered to initiate the recovery procedure. The beam failure recovery mainly consists of the following components. The first component is beam failure detection where UE monitors a certain reference signal (RS) configured by gNB to evaluate the quality of the employed beam. The second component is new beam selection where UE measures the beams in the candidate lists configured by gNB. In case of beam failure, UE shall propose one of the candidates. The third component is beam recovery where when a beam failure is detected by UE, UE shall initiate a contention-free random-access procedure, which is used to report the beam candidate above. The details of beam failure recovery are available from 3GPP technical specification (TS) 38.331 V15.1.0, TS 38.321 V15.1.0 and TS 38.214 V15.1.0.

Summary

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

One of the objects of the disclosure is to provide an improved solution for beam management.

According to a first aspect of the disclosure, there is provided a method performed by an access network node. The method may comprise detecting a first event in which a physical downlink control channel (PDCCH) carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. The method may further comprise obtaining, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. The method may further comprise updating a beam management configuration for the terminal device, based on the beam management report.

In this way, a proper beam management configuration can be configured for a terminal device to improve the robustness of PDCCH.

In an embodiment of the disclosure, the first event may be detected when a second event occurs in which the feedback information indicates neither acknowledgment nor non-acknowledgment for one of the scheduled one or more downlink transmissions.

In an embodiment of the disclosure, the first event may be detected when the second event occurs multiple times during a first predetermined time period.

In an embodiment of the disclosure, the feedback information may be hybrid automatic repeat request (HARQ) information.

In an embodiment of the disclosure, obtaining the beam management report from the terminal device may comprise transmitting, to the terminal device, an uplink grant for transmission of the beam management report. Obtaining the beam management report from the terminal device may further comprise receiving the beam management report from the terminal device.

In an embodiment of the disclosure, the beam management report may be an aperiodic channel state information (CSI) report.

In an embodiment of the disclosure, multiple successive beam management reports each indicating a second transmission beam favorite for the terminal device may be obtained.

In an embodiment of the disclosure, the beam management configuration may be updated by one or more of: transmitting PDCCH with a target transmission beam instead of the first transmission beam; configuring a shorter periodicity of beam management report; and configuring beam failure candidate reference signal (RS) to synchronization signal block (SSB) .

In an embodiment of the disclosure, the target transmission beam may be: the second transmission beam; or one of the second transmission beams indicated in multiple successive beam management reports; or a third transmission beam that overlaps with the second transmission beam or one of the second transmission beams and has a wider width than the second transmission beam or one of the second transmission beams.

In an embodiment of the disclosure, the beam management configuration may be updated based on a beam change level. The beam change level may be determined based on the beam management report.

In an embodiment of the disclosure, a high beam change level may be determined for the terminal device when one of following conditions is satisfied: a difference between beam indexes of the second and first transmission beams is outside a predetermined range; and the second transmission beams indicated in multiple successive beam management reports indicate that a location of the terminal device changes with time.

In an embodiment of the disclosure, the third transmission beam may be used as the target transmission beam when a high beam change level is determined for the terminal device.

In an embodiment of the disclosure, at least one of the shorter periodicity and the beam failure candidate RS may be configured when a high beam change level is determined for the terminal device.

In an embodiment of the disclosure, the PDCCH may be transmitted after the terminal device has no downlink data to receive for a second predetermined time period. Padding data may be transmitted in the one or more downlink transmissions scheduled by the PDCCH.

In an embodiment of the disclosure, the updated beam management configuration may be kept when no more first event is detected after updating the beam management configuration.

In an embodiment of the disclosure, the updated beam management configuration may be changed back to an original beam management configuration, when the first event is detected during a third predetermined time period after updating the beam management configuration.

According to a second aspect of the disclosure, there is provided an access network node. The access network node may comprise at least one processor and at least one memory. The at least one memory may contain instructions executable by the at least one processor, whereby the access network node may be operative to detect a first event in which a PDCCH carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. The access network node may be further operative to obtain, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. The access network node may be further operative to update a beam management configuration for the terminal device, based on the beam management report.

In an embodiment of the disclosure, the access network node may be operative to perform the method according to the above first aspect.

According to a third aspect of the disclosure, there is provided a computer program product. The computer program product may comprise instructions which when executed by at least one processor, cause the at least one processor to perform the method according to the above first aspect.

According to a fourth aspect of the disclosure, there is provided a computer readable storage medium. The computer readable storage medium may comprise instructions which when executed by at least one processor, cause the at least one processor to perform the method according to the above first aspect.

According to a fifth aspect of the disclosure, there is provided an access network node. The access network node may comprise a detection module for detecting a first event in which a PDCCH carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. The access network node may further comprise an obtaining module for obtaining, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. The access network node may further comprise an updating module for updating a beam management configuration for the terminal device, based on the beam management report.

Brief Description of the Drawings

These and other objects, features and advantages of the disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which are to be read in connection with the accompanying drawings.

FIG. 1 is a diagram illustrating the relation between different CSI-RS resources and different CSI reports;

FIG. 2 is a diagram illustrating a possible problem with the existing solution;

FIG. 3 is a flowchart illustrating a method implemented at an access network node according to an embodiment of the disclosure;

FIG. 4 is a diagram illustrating an example for TDD dynamic HARQ;

FIG. 5 is a flowchart for explaining the method of FIG. 3;

FIG. 6 is a flowchart for explaining the method of FIG. 3;

FIG. 7 is a flowchart illustrating an exemplary process according to an embodiment of the disclosure;

FIG. 8 is a block diagram showing an apparatus suitable for use in practicing some embodiments of the disclosure;

FIG. 9 is a block diagram showing an access network node according to an embodiment of the disclosure;

FIG. 10 is a diagram showing a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments;

FIG. 11 is a diagram showing a host computer communicating via a base station with a user equipment in accordance with some embodiments;

FIG. 12 is a flowchart illustrating a method implemented in a communication system in accordance with some embodiments;

FIG. 13 is a flowchart illustrating a method implemented in a communication system in accordance with some embodiments;

FIG. 14 is a flowchart illustrating a method implemented in a communication system in accordance with some embodiments; and

FIG. 15 is a flowchart illustrating a method implemented in a communication system in accordance with some embodiments.

Detailed Description

For the purpose of explanation, details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed. It is apparent, however, to those skilled in the art that the embodiments may be implemented without these specific details or with an equivalent arrangement.

References in the specification to “one embodiment” , “an embodiment” , “an example embodiment” , and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. Some of the embodiments described separately or independently hereafter may also be implemented in combination depending on various application scenarios.

Generally, a physical downlink control channel (PDCCH) beam is selected from beam management. If it does not work well, beam failure recovery would be triggered by UE.

With respect to beam management, the reference signal can either be synchronization signal block (SSB) or channel state information reference signal (CSI-RS) . Take CSI-RS as an example, 3GPP supported combinations of CSI-RS resources and CSI reports are shown in FIG. 1. The term AP refers to aperiodic, the term SP refers to semi-persistent, and the letter P refers to periodic. Due to beam tracking and beam refinement purpose, period CSI-RS and CSI report are widely used in beam management.

With a longer period of CSI report or a longer interval for AP-CSI report in beam management, there would be a problem shown in FIG. 2. For a moving UE, if the UE moves inside one pre-defined beam (point 1) , PDCCH link adaptation (LA) would take effect to track PDCCH channel quality and no beam change is needed in this case. If the UE moves from point 1 to point 2, due to the long period of CSI report by beam management, several beam failure recovery procedures would be triggered by the UE. And this would cause random access (RA) frequently.

Furthermore, a short period of CSI report or a short interval for AP-CSI report in beam management is good for UE beam tracking but with the problems as below. Firstly, heavy load of CSI payload on physical uplink shared channel (PUSCH) or physical uplink control channel (PUCCH) would be incurred, which left less resource for data transmission. Secondly, AP-CSI report which is scheduled by UL grant may occupy the scheduled opportunity of other UEs with data. Thirdly, AP-CSI report would make delay of downlink (DL) hybrid automatic repeat request (HARQ) .

With respect to beam failure recovery, according to 3GPP TS 38.331 V15.1.0, a UE can be configured with maximum 16 (maxNrofCandidateBeams) beams for new beam detection in beam failure recovery. The candidate RS can either be SSB or CSI-RS. The CSI-RS is associated with a narrower beam, which has a higher beamforming (BF) gain. The SSB is associated with a wider beam, which has a larger PDCCH coverage.

For beam failure candidate reference signal configuration, only a limited number (16) of reference signals can be configured for beam failure. With UE movement, the configured RS may not cover the UE anymore. The more configured RS, the more measurement would be done by the UE. This would bring the problem for UE battery.

Based on the above, it is difficult to configure proper parameters for beam management and beam failure recovery considering PDCCH robustness.

The present disclosure proposes an improved solution for beam management. The solution may be applied to a communication system including a terminal device and an access network node. For example, the access network node may be a base station such as a gNB in NR. The terminal device can communicate through a radio access communication link with the base station. The base station can provide radio access communication links to terminal devices that are within its communication service cell. Note that the communications may be performed between the terminal device and the base station according to any suitable communication standards and protocols.

The terminal device may also be referred to as, for example, device, access terminal, user equipment (UE) , mobile station, mobile unit, subscriber station, or the like. It may refer to any end device that can access a wireless communication network and receive services therefrom. By way of example and not limitation, the terminal device may include a portable computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and playback appliance, a mobile phone, a cellular phone, a smart phone, a tablet, a wearable device, a personal digital assistant (PDA) , or the like.

In an Internet of things (IoT) scenario, a terminal device may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another terminal device and/or a network equipment. In this case, the terminal device may be a machine-to-machine (M2M) device, which may, in a 3GPP context, be referred to as a machine-type communication (MTC) device. Particular examples of such machines or devices may include sensors, metering devices such as power meters, industrial machineries, bikes, vehicles, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches, and so on.

Hereinafter, the solution will be described in detail with reference to FIGs. 3-15. FIG. 3 is a flowchart illustrating a method implemented at an access network node according to an embodiment of the disclosure. At block 302, the access network node detects a first event in which a PDCCH carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. For example, the feedback information may be HARQ information. As an option, the first event may be detected when a second event occurs in which the feedback information indicates neither acknowledgment nor non-acknowledgment for one of the scheduled one or more downlink transmissions. Note that the first event may be detected when more than one second events occur in which the feedback information indicates neither acknowledgment nor non-acknowledgment for more than one scheduled downlink transmissions. As another option, the first event may be detected when the second event occurs multiple times during a first predetermined time period. For example, the first predetermined time period may be set according to a preconfigured timer.

As an exemplary example, suppose the HARQ information is time division duplexing (TDD) dynamic HARQ report as shown in FIG. 4. The HARQ acknowledgement/non-acknowledgement (A/N) of downlink (DL) slot 1～3 are reported in the same UL slot 9. The HARQ A/N of DL slot 4～7 are reported in the same UL slot 10. The term “8S” means that slot 8 is a special slot with both UL and DL symbols. Suppose one UE is scheduled continuously in DL slot 1～3 and using three carriers in carrier aggregation (CA) case. Then, the HARQ A/N bits will be sent together in UL slot 9 with 9 bits in normal case, as shown in the table below.

This information about the normal case (e.g. 9 bits of HARQ A/N) may not match the HARQ report (e.g. 8 bits of HARQ A/N) sent by the UE, if part of DL grants carried by PDCCH is not received by the UE. Based on this, the access network node can detect the first event.

Note that there is one scenario that the access network node cannot distinguish DL problem (PDCCH not received) with UL problem (PUCCH not received) . For instance, all DL grants for the bundling time (e.g. DL slot 1～3) and CA carriers are not received. In a case that aperiodic CSI report (s) are triggered in block 304 described later, this problem can be solved by monitoring the aperiodic CSI report (s) from the UE. If the aperiodic CSI report (s) are received by the access network node, it means the UE can receive PDCCH (the grant for the aperiodic CSI report (s) ) successfully. Otherwise, it may be determined as UL problem.

At block 304, the access network node obtains, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. Note that there may be more than one second transmission beams indicated in one beam management report. For example, the beam management report may be an aperiodic CSI report for achieving fast beam management. In this case, block 304 may be implemented as blocks 508-510 of FIG. 5. At block 508, the access network node transmits, to the terminal device, an uplink grant for transmission of the beam management report. At block 510, the access network node receives the beam management report from the terminal device.

It should be noted that obtaining the beam management report may comprise obtaining multiple successive beam management reports each indicating a second transmission beam favorite for the terminal device. For example, several aperiodic CSI-RS/reports may be scheduled in a row with a time interval to indicate whether the favorite transmission beam continues changing or not.

At block 306, the access network node updates a beam management configuration for the terminal device, based on the beam management report. In this way, a proper beam management configuration can be configured for a terminal device to improve the robustness of PDCCH. For example, the beam management configuration may include one or more of: the transmission beam used for transmitting PDCCH, the periodicity of beam management report, and the beam failure candidate RS. As shown in FIG. 6, block 306 may be implemented as block 306-1 or blocks 306-2～306-3. At block 306-1, the beam management configuration is updated for the terminal device when the second transmission beam is different from the first transmission beam.

As a first example, the beam management configuration may be updated by transmitting PDCCH with a target transmission beam instead of the first transmission beam. If one beam management report is obtained at block 304, the target transmission beam may be the second transmission beam. Note that if multiple second transmission beams are indicated in the one beam management report, one of the multiple second transmission beams may be selected as the target transmission beam. If multiple successive beam management reports are obtained at block 304, the target transmission beam may be one of the second transmission beams indicated in the multiple successive beam management reports. Alternatively, the target transmission beam may be a third transmission beam that overlaps with the second transmission beam or one of the second transmission beams and has a wider width than the second transmission beam or one of the second transmission beams.

As a second example, the beam management configuration may be updated by configuring a shorter periodicity of beam management report. As a third example, the beam management configuration may be updated by configuring beam failure candidate RS to SSB. Note that any two or more of the above three examples may be used in combination to update the beam management configuration.

At block 306-2, a beam change level is determined for the terminal device based on the beam management report. As an example, a high beam change level may be determined for the terminal device when a difference between beam indexes of the second and first transmission beams is outside a predetermined range. As another example, a high beam change level may be determined for the terminal device when the second transmission beams indicated in multiple successive beam management reports indicate that a location of the terminal device changes with time.

At block 306-3, the beam management configuration is updated for the terminal device based on the beam change level. As an example, the third transmission beam may be used as the target transmission beam when a high beam change level is determined for the terminal device. On the other hand, the second transmission beam or one of the second transmission beams indicated in the multiple successive beam management reports (e.g. the second transmission beam indicated in the last beam management report) may be used as the target transmission beam when a low beam change level is determined for the terminal device. As another example, at least one of the shorter periodicity and the beam failure candidate RS may be configured when a high beam change level is determined for the terminal device.

Optionally, the PDCCH may be transmitted after the terminal device has no downlink data to receive for a second predetermined time period. Padding data may be transmitted in the one or more downlink transmissions scheduled by the PDCCH. In other words, a UE may be scheduled in DL after a period of time even without DL data so that the access network node can get DL HARQ.

Optionally, the updated beam management configuration may be kept when no more first event is detected after updating the beam management configuration. On the other hand, the updated beam management configuration may be changed back to an original beam management configuration (e.g. the legacy beam management configuration) , when the first event is detected during a third predetermined time period after updating the beam management configuration.

FIG. 7 is a flowchart illustrating an exemplary process according to an embodiment of the disclosure. As shown, in this process, the access network node is a gNB. At block 701, the UE transmits DL HARQ to the gNB. Suppose the gNB detects the first event based on the DL HARQ. Then, at block 702, the gNB schedules an aperiodic CSI-RS/report for beam change detection by transmitting corresponding grant to the UE. At block 703, the UE transmits an aperiodic CSI report to the gNB. At block 704, the gNB update (or modify) a beam management configuration for the UE based on the aperiodic CSI report.

As shown in the example of FIG. 2, the first event may be caused by UE moving/channel change either inside the beam of point 1 or from the beam of point 1 to the beam of point 2. One or several aperiodic CSI reports may be scheduled at block 702 to distinguish those two scenarios. If the reported beam index is the same with the previous beam index, this means the UE is still inside the selected beam. Thus, no actions may be taken by the gNB. If the reported beam index is different from the previous beam index, this means the UE is moving out of the selected beam. Thus, the gNB may configure PDCCH with the new reported beam at block 704. If the UE continues moving towards other beam areas, a wide beam may be configured to PDCCH, or a shorter periodicity may be configured to beam management, or an SSB may be configured/re-configured to beam failure candidate RS at block 704.

Optionally, different UEs may be classified into different beam change levels according to the aperiodic CSI report received at block 703. As an example, if the new reported beam is different with the currently used beam, the UE may be set as low beam change level. As another example, the beam change level may be set according to the distance (e.g. the beam index difference) between the currently used beam and the reported beam. As another example, if the reported beams from several aperiodic CSI-RS/reports change in a row, the UE may be set as high beam change level.

Optionally, the beam management configuration (e.g. the PDCCH transmission beam, the periodicity for beam management report, the beam failure candidate RS) may be updated (e.g. configured/reconfigured) according to the beam change level. As an example, for all beam change levels, the new reported beam may be used for DL PDCCH transmission. As another example, for low beam change level, the new reported beam may be used for DL PDCCH transmission. For high beam change level, a shorter periodicity for beam management measurement may be configured/re-configured and/or the beam failure candidate RS may be configured/re-configured to SSB.

Optionally, the gNB may keep on detecting the first event after block 703 for further configuration adjustment. As an example, if no more first event is detected after block 703, the gNB may keep the updated configuration. As another example, if the first event is detected after block 703 during a certain time, some original parameter (s) before block 703 (e.g. some original parameter (s) configured according to the legacy solution) may be re-configured to the UE. Then the method shown in FIG. 3 may be repeated again.

FIG. 8 is a block diagram showing an apparatus suitable for use in practicing some embodiments of the disclosure. For example, the access network node described above may be implemented through the apparatus 800. As shown, the apparatus 800 may include a processor 810, a memory 820 that stores a program, and optionally a communication interface 830 for communicating data with other external devices through wired and/or wireless communication.

The program includes program instructions that, when executed by the processor 810, enable the apparatus 800 to operate in accordance with the embodiments of the present disclosure, as discussed above. That is, the embodiments of the present disclosure may be implemented at least in part by computer software executable by the processor 810, or by hardware, or by a combination of software and hardware.

The memory 820 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 memories, magnetic memory devices and systems, optical memory devices and systems, fixed memories and removable memories. The processor 810 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 multi-core processor architectures, as non-limiting examples.

FIG. 9 is a block diagram showing an access network node according to an embodiment of the disclosure. As shown, the access network node 900 comprises a detection module 902, an obtaining module 904 and an updating module 906. The detection module 902 may be configured to detect a first event in which a PDCCH carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH, as described above with respect to block 302. The obtaining module 904 may be configured to obtain, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device, as described above with respect to block 304. The updating module 906 may be configured to update a beam management configuration for the terminal device, based on the beam management report, as described above with respect to block 306. The modules described above may be implemented by hardware, or software, or a combination of both.

With reference to FIG. 10, in accordance with an embodiment, a communication system includes telecommunication network 3210, such as a 3GPP-type cellular network, which comprises access network 3211, such as a radio access network, and core network 3214. Access network 3211 comprises a plurality of

base stations

3212a, 3212b, 3212c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a

corresponding coverage area

3213a, 3213b, 3213c. Each

base station

3212a, 3212b, 3212c is connectable to core network 3214 over a wired or wireless connection 3215. A first UE 3291 located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c. A second UE 3292 in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a. While a plurality of

UEs

3291, 3292 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 3212.

Telecommunication network 3210 is itself connected to host computer 3230, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. Host computer 3230 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider.

Connections

3221 and 3222 between telecommunication network 3210 and host computer 3230 may extend directly from core network 3214 to host computer 3230 or may go via an optional intermediate network 3220. Intermediate network 3220 may be one of, or a combination of more than one of, a public, private or hosted network; intermediate network 3220, if any, may be a backbone network or the Internet; in particular, intermediate network 3220 may comprise two or more sub-networks (not shown) .

The communication system of FIG. 10 as a whole enables connectivity between the connected

UEs

3291, 3292 and host computer 3230. The connectivity may be described as an over-the-top (OTT) connection 3250. Host computer 3230 and the connected

UEs

3291, 3292 are configured to communicate data and/or signaling via OTT connection 3250, using access network 3211, core network 3214, any intermediate network 3220 and possible further infrastructure (not shown) as intermediaries. OTT connection 3250 may be transparent in the sense that the participating communication devices through which OTT connection 3250 passes are unaware of routing of uplink and downlink communications. For example, base station 3212 may not or need not be informed about the past routing of an incoming downlink communication with data originating from host computer 3230 to be forwarded (e.g., handed over) to a connected UE 3291. Similarly, base station 3212 need not be aware of the future routing of an outgoing uplink communication originating from the UE 3291 towards the host computer 3230.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to FIG. 11. In communication system 3300, host computer 3310 comprises hardware 3315 including communication interface 3316 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of communication system 3300. Host computer 3310 further comprises processing circuitry 3318, which may have storage and/or processing capabilities. In particular, processing circuitry 3318 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Host computer 3310 further comprises software 3311, which is stored in or accessible by host computer 3310 and executable by processing circuitry 3318. Software 3311 includes host application 3312. Host application 3312 may be operable to provide a service to a remote user, such as UE 3330 connecting via OTT connection 3350 terminating at UE 3330 and host computer 3310. In providing the service to the remote user, host application 3312 may provide user data which is transmitted using OTT connection 3350.

Communication system 3300 further includes base station 3320 provided in a telecommunication system and comprising hardware 3325 enabling it to communicate with host computer 3310 and with UE 3330. Hardware 3325 may include communication interface 3326 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of communication system 3300, as well as radio interface 3327 for setting up and maintaining at least wireless connection 3370 with UE 3330 located in a coverage area (not shown in FIG. 11) served by base station 3320. Communication interface 3326 may be configured to facilitate connection 3360 to host computer 3310. Connection 3360 may be direct or it may pass through a core network (not shown in FIG. 11) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, hardware 3325 of base station 3320 further includes processing circuitry 3328, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Base station 3320 further has software 3321 stored internally or accessible via an external connection.

Communication system 3300 further includes UE 3330 already referred to. Its hardware 3335 may include radio interface 3337 configured to set up and maintain wireless connection 3370 with a base station serving a coverage area in which UE 3330 is currently located. Hardware 3335 of UE 3330 further includes processing circuitry 3338, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. UE 3330 further comprises software 3331, which is stored in or accessible by UE 3330 and executable by processing circuitry 3338. Software 3331 includes client application 3332. Client application 3332 may be operable to provide a service to a human or non-human user via UE 3330, with the support of host computer 3310. In host computer 3310, an executing host application 3312 may communicate with the executing client application 3332 via OTT connection 3350 terminating at UE 3330 and host computer 3310. In providing the service to the user, client application 3332 may receive request data from host application 3312 and provide user data in response to the request data. OTT connection 3350 may transfer both the request data and the user data. Client application 3332 may interact with the user to generate the user data that it provides.

It is noted that host computer 3310, base station 3320 and UE 3330 illustrated in FIG. 11 may be similar or identical to host computer 3230, one of

base stations

3212a, 3212b, 3212c and one of

UEs

3291, 3292 of FIG. 10, respectively. This is to say, the inner workings of these entities may be as shown in FIG. 11 and independently, the surrounding network topology may be that of FIG. 10.

In FIG. 11, OTT connection 3350 has been drawn abstractly to illustrate the communication between host computer 3310 and UE 3330 via base station 3320, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from UE 3330 or from the service provider operating host computer 3310, or both. While OTT connection 3350 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network) .

Wireless connection 3370 between UE 3330 and base station 3320 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE 3330 using OTT connection 3350, in which wireless connection 3370 forms the last segment. More precisely, the teachings of these embodiments may improve the latency and thereby provide benefits such as reduced user waiting time.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring OTT connection 3350 between host computer 3310 and UE 3330, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring OTT connection 3350 may be implemented in software 3311 and hardware 3315 of host computer 3310 or in software 3331 and hardware 3335 of UE 3330, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which OTT connection 3350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which

software

3311, 3331 may compute or estimate the monitored quantities. The reconfiguring of OTT connection 3350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect base station 3320, and it may be unknown or imperceptible to base station 3320. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating host computer 3310’s measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that

software

3311 and 3331 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using OTT connection 3350 while it monitors propagation times, errors etc.

FIG. 12 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIGs. 10 and 11. For simplicity of the present disclosure, only drawing references to FIG. 12 will be included in this section. In step 3410, the host computer provides user data. In substep 3411 (which may be optional) of step 3410, the host computer provides the user data by executing a host application. In step 3420, the host computer initiates a transmission carrying the user data to the UE. In step 3430 (which may be optional) , the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 3440 (which may also be optional) , the UE executes a client application associated with the host application executed by the host computer.

FIG. 13 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIGs. 10 and 11. For simplicity of the present disclosure, only drawing references to FIG. 13 will be included in this section. In step 3510 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In step 3520, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In step 3530 (which may be optional) , the UE receives the user data carried in the transmission.

FIG. 14 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIGs. 10 and 11. For simplicity of the present disclosure, only drawing references to FIG. 14 will be included in this section. In step 3610 (which may be optional) , the UE receives input data provided by the host computer. Additionally or alternatively, in step 3620, the UE provides user data. In substep 3621 (which may be optional) of step 3620, the UE provides the user data by executing a client application. In substep 3611 (which may be optional) of step 3610, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in substep 3630 (which may be optional) , transmission of the user data to the host computer. In step 3640 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

FIG. 15 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to FIGs. 10 and 11. For simplicity of the present disclosure, only drawing references to FIG. 15 will be included in this section. In step 3710 (which may be optional) , in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In step 3720 (which may be optional) , the base station initiates transmission of the received user data to the host computer. In step 3730 (which may be optional) , the host computer receives the user data carried in the transmission initiated by the base station.

According to an aspect of the disclosure, there is provided a method implemented in a communication system including a host computer, a base station and a terminal device. The method may comprise, at the host computer, providing user data. The method may further comprise, at the host computer, initiating a transmission carrying the user data to the terminal device via a cellular network comprising the base station. The base station may detect a first event in which a PDCCH carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. The base station may obtain, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. The base station may update a beam management configuration for the terminal device, based on the beam management report.

In an embodiment of the disclosure, the method may further comprise, at the base station, transmitting the user data.

In an embodiment of the disclosure, the user data may be provided at the host computer by executing a host application. The method may further comprise, at the terminal device, executing a client application associated with the host application.

According to another aspect of the disclosure, there is provided a communication system including a host computer comprising processing circuitry configured to provide user data and a communication interface configured to forward the user data to a cellular network for transmission to a terminal device. The cellular network may comprise a base station having a radio interface and processing circuitry. The base station’s processing circuitry may be configured to detect a first event in which a PDCCH carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH. The base station’s processing circuitry may be further configured to obtain, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device. The base station’s processing circuitry may be further configured to update a beam management configuration for the terminal device, based on the beam management report.

In an embodiment of the disclosure, the communication system may further include the base station.

In an embodiment of the disclosure, the communication system may further include the terminal device. The terminal device may be configured to communicate with the base station.

In an embodiment of the disclosure, the processing circuitry of the host computer may be configured to execute a host application, thereby providing the user data. The terminal device may comprise processing circuitry configured to execute a client application associated with the host application.

In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, RAM, etc. As will be appreciated by one skilled in the art, the function of the program modules may be combined or distributed as desired in various embodiments. In addition, the function may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

References in the present disclosure to “one embodiment” , “an embodiment” and so on, indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. It should be noted that two blocks shown in succession in the figures may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

It should be understood that, although the terms “first” , “second” and so on may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of the disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The terms “connect” , “connects” , “connecting” and/or “connected” used herein cover the direct and/or indirect connection between two elements.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-Limiting and exemplary embodiments of this disclosure.

Claims

A method performed by an access network node, comprising:

detecting (302) a first event in which a physical downlink control channel, PDCCH, carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH;

obtaining (304) , from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device; and

updating (306) a beam management configuration for the terminal device, based on the beam management report.
The method according to claim 1, wherein the first event is detected when a second event occurs in which the feedback information indicates neither acknowledgment nor non-acknowledgment for one of the scheduled one or more downlink transmissions.
The method according to claim 2, wherein the first event is detected when the second event occurs multiple times during a first predetermined time period.
The method according to any of claims 1 to 3, wherein the feedback information is hybrid automatic repeat request, HARQ, information.
The method according to any of claims 1 to 4, wherein obtaining (304) the beam management report from the terminal device comprises:

transmitting (508) , to the terminal device, an uplink grant for transmission of the beam management report; and

receiving (510) the beam management report from the terminal device.
The method according to any of claims 1 to 5, wherein the beam management report is an aperiodic channel state information, CSI, report.
The method according to any of claims 1 to 6, wherein multiple successive beam management reports each indicating a second transmission beam favorite for the terminal device are obtained.
The method according to any of claims 1 to 7, wherein the beam management configuration is updated by one or more of:

transmitting PDCCH with a target transmission beam instead of the first transmission beam;

configuring a shorter periodicity of beam management report; and

configuring beam failure candidate reference signal, RS, to synchronization signal block, SSB.
The method according to claim 8, wherein the target transmission beam is:

the second transmission beam; or

one of the second transmission beams indicated in multiple successive beam management reports; or

a third transmission beam that overlaps with the second transmission beam or one of the second transmission beams and has a wider width than the second transmission beam or one of the second transmission beams.
The method according to claim 8, wherein the beam management configuration is updated based on a beam change level and wherein the beam change level is determined based on the beam management report.
The method according to claim 10, wherein a high beam change level is determined for the terminal device when one of following conditions is satisfied:

a difference between beam indexes of the second and first transmission beams is outside a predetermined range; and

the second transmission beams indicated in multiple successive beam management reports indicate that a location of the terminal device changes with time.
The method according to claim 9, wherein the third transmission beam is used as the target transmission beam when a high beam change level is determined for the terminal device.
The method according to claim 12, wherein a high beam change level is determined for the terminal device when one of following conditions is satisfied:

a difference between beam indexes of the second and first transmission beams is outside a predetermined range; and

the second transmission beams indicated in multiple successive beam management reports indicate that a location of the terminal device changes with time.
The method according to any of claims 10 to 13, wherein at least one of the shorter periodicity and the beam failure candidate RS is configured when a high beam change level is determined for the terminal device.
The method according to any of claims 1 to 14, wherein the PDCCH is transmitted after the terminal device has no downlink data to receive for a second predetermined time period; and

wherein padding data is transmitted in the one or more downlink transmissions scheduled by the PDCCH.
The method according to any of claims 1 to 15, wherein the updated beam management configuration is kept when no more first event is detected after updating the beam management configuration.
The method according to any of claims 1 to 15, wherein the updated beam management configuration is changed back to an original beam management configuration, when the first event is detected during a third predetermined time period after updating the beam management configuration.
An access network node (800) comprising:

at least one processor (810) ; and

at least one memory (820) , the at least one memory (820) containing instructions executable by the at least one processor (810) , whereby the access network node (800) is operative to:

detect a first event in which a physical downlink control channel, PDCCH, carried by a first transmission beam is not received by a terminal device, based on feedback information from the terminal device about one or more downlink transmissions scheduled by the PDCCH;

obtain, from the terminal device, a beam management report indicating a second transmission beam favorite for the terminal device; and

update a beam management configuration for the terminal device, based on the beam management report.
The access network node (800) according to claim 18, wherein the access network node (800) is operative to perform the method according to any of claims 2 to 17.
A computer readable storage medium comprising instructions which when executed by at least one processor, cause the at least one processor to perform the method according to any of claims 1 to 17.