EP4252473A1

EP4252473A1 - Triggering assessment of a shared channel

Info

Publication number: EP4252473A1
Application number: EP21830539.9A
Authority: EP
Inventors: Yuhang Liu; Peter Alriksson; Reem KARAKI; Stephen Grant; Narendar Madhavan; Tai Do
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2020-11-27
Filing date: 2021-11-24
Publication date: 2023-10-04
Also published as: WO2022115026A1

Abstract

A base station (1400) in a wireless communication network transmits, to a user equipment (1300) and on a downlink control channel, a trigger signal that triggers the user equipment (1300) to assess a shared channel. The trigger signal also configures the user equipment (1300) with radio resources of an uplink channel with which to report a result of the assessment. The base station receives, on the radio resources of the uplink channel, the report of the result of the assessment performed by the user equipment (1300) and transmits data on the shared downlink channel to the user equipment (1300). The transmitting of the data is based on the result of the assessment performed by the user equipment (1300).

Description

TRIGGERING ASSESSMENT OF A SHARED CHANNEL

RELATED APPLICATIONS

This application claims priority to U.S. Application No. 63/118743 filed on November 27, 2020, the entire disclosure of which is incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to a technique for triggering assessment of a shared channel. More specifically, and without limitation, methods and devices are provided for reporting, triggering, and receiving a CCA of a radio channel that is shared according to a channel access mechanism.

BACKGROUND

The Third Generation Partnership Project (3GPP) defines mobile broadband to continue to drive the demands for higher overall traffic capacity and higher achievable end-user data rates in the wireless access network. Several scenarios in the future will require data rates of up to 10 Gbps in local areas. These demands for very high system capacity and very high end-user date rates can be met by networks with distances between access nodes ranging from a few meters in indoor deployments up to roughly 50 m in outdoor deployments, i.e., with an infra-structure density considerably higher than the densest networks of today. The wide transmission bandwidths needed to provide data rates up to 10 Gbps and above can likely only be obtained from spectrum allocations in the millimeter-wave band. High-gain beamforming, typically realized with array antennas, can be used to mitigate the increased pathloss at higher frequencies. Networks and radio access technology using beamforming are referred to as New Radio (NR) in the following, particularly as 3GPP NR or Fifth Generation NR (5G NR).

Besides traditional licensed exclusive bands, NR systems can operate on unlicensed bands, especially for enterprise solutions or campus networks. Thus, coexistence support is needed to enable spectrum sharing between different operators or other systems. A Listen-Before- Talk (LBT) mechanism is the most flexible way to achieve this. The most important reason is that it is a distributed mechanism so that there are no needs to exchange information between different systems which may be more difficult.

However, such a distributed approach can cause the so-called hidden-node problem and the exposed-node problem, especially when using beamforming.

SUMMARY

Accordingly, there is a need for a technique that allows efficiently sharing a radio channel, preferably for beamformed transmissions. An alternative or more specific object is to implement such a technique with minimal modification to existing systems and specifications for NR. Particular embodiments include a method implemented by a base station in a wireless communication network. The method comprises transmitting, to a user equipment and on a downlink control channel, a trigger signal that triggers the user equipment to assess a shared channel. The trigger signal also configures the user equipment with radio resources of an uplink channel with which to report a result of the assessment. The method further comprises receiving, on the radio resources of the uplink channel, the report of the result of the assessment performed by the user equipment. The method further comprises transmitting data on the shared channel to the user equipment. The transmitting of the data is based on the result of the assessment performed by the user equipment.

In some embodiments, the trigger signal triggers the user equipment to perform a Clear Channel Assessment, CCA, or a channel measurement of the shared channel. In some such embodiments, the report comprises a one-bit flag indicating either success or failure of the CCA respectively representing whether or not a signal quality of the uplink channel is better than a quality threshold. In other such embodiments, the report comprises a Received Signal Strength Indicator, a Reference Signal Received Power, a Signal-to-Noise Ratio, and/or a Signal-to- Interference-and-Noise Ratio of the shared channel.

In some embodiments, the radio resources comprise a first portion allocated for a demodulation reference signal, DMRS, and a second portion allocated for corresponding Uplink Control Information, UCI. Further, receiving the report of the result of the assessment on the radio resources comprises receiving an indication that the uplink channel is clear. Further, receiving the indication that the uplink is clear comprises receiving the DMRS on the first portion of the resources and the second portion of the resources being empty.

In some embodiments, the method further comprises configuring the user equipment with a resource set, wherein the report of the result of the assessment indicates a measurement of the resource set taken by the user equipment. In some such embodiments, the resource set comprises time/frequency resources for aperiodic Channel State Information Reference Signal, CSI-RS, reporting, a bandwidth and a duration over which to perform the measurement of the resource set, a synchronization signal block, and/or a Channel State Information Interference Measurement, CSI-IM, resource.

In some embodiments, receiving the report of the result of the assessment comprises receiving the report of the result in an aperiodic Channel State Information (CSI) report.

In some embodiments, transmitting the trigger signal comprises transmitting the trigger signal in an uplink grant.

Other embodiments include a method implemented by a user equipment in a wireless communication network. The method comprises receiving, from a base station and on a downlink control channel, a trigger signal that triggers the user equipment to assess a shared channel. The trigger signal also configures the user equipment with radio resources of an uplink channel with which to report a result of the assessment. The method further comprises assessing the shared channel in response to the trigger signal. The method further comprises transmitting, on the radio resources of the uplink channel, the report of the result of the assessment and receiving data on the shared channel from the base station in response.

In some embodiments, the trigger signal triggers the user equipment to perform a Clear Channel Assessment, CCA, or a channel measurement of the shared channel. In some such embodiments, the report comprises a one-bit flag indicating either success or failure of the CCA respectively representing whether or not a signal quality of the uplink channel is better than a quality threshold. In other such embodiments the report comprises a Received Signal Strength Indicator, a Reference Signal Received Power, a Signal-to-Noise Ratio, and/or a Signal-to- Interference-and-Noise Ratio of the shared channel.

In some embodiments, the radio resources comprise a first portion allocated for a demodulation reference signal, DMRS, and a second portion allocated for corresponding Uplink Control Information, UCI. Further, transmitting the report of the result of the assessment on the radio resources comprises transmitting an indication that the uplink channel is clear. Further, transmitting the indication that the uplink is clear comprises transmitting the DMRS on the first portion of the resources and leaving the second portion of the resources empty.

In some embodiments, the method further comprises receiving a resource set from the base station. The report of the result of the assessment indicates a measurement of the resource set taken by the user equipment. In some such embodiments, the method further comprises time/frequency resources for aperiodic Channel State Information Reference Signal, CSI-RS, reporting, a bandwidth and a duration over which to perform the measurement of the resource set, a synchronization signal block, and/or a Channel State Information Interference Measurement, CSI-IM, resource.

In some embodiments, transmitting the report of the result of the assessment comprises transmitting the report of the result in an aperiodic Channel State Information, CSI, report.

In some embodiments, receiving the trigger signal comprises receiving the trigger signal in an uplink grant.

Other embodiments include a base station comprising a processor and a memory. The memory contains instructions executable by the processor whereby the base station is configured to transmit, to a user equipment and on a downlink control channel, a trigger signal that triggers the user equipment to assess a shared channel. The trigger signal also configures the user equipment with radio resources of an uplink channel with which to report a result of the assessment. The base station is further configured to receive, on the radio resources of the uplink channel, the report of the result of the assessment performed by the user equipment. The base station is further configured to transmit data on the shared channel to the user equipment. The transmitting of the data is based on the result of the assessment performed by the user equipment.

In some embodiments, the base station is further configured to perform any of the base station methods described above. Other embodiments include a computer program, comprising instructions which, when executed on a processor of a base station, cause the processor to carry out the any of the base station methods described above.

Yet other embodiments include a user equipment. The user equipment comprises a processor and a memory. The memory contains instructions executable by the processor whereby the user equipment is configured to receive, from a base station and on a downlink control channel, a trigger signal that triggers the user equipment to assess a shared channel. The trigger signal also configures the user equipment with radio resources of an uplink channel with which to report a result of the assessment. The user equipment is further configured to assess the shared channel in response to the trigger signal. The user equipment is further configured to transmit, on the radio resources of the uplink channel, the report of the result of the assessment and receive data on the shared channel from the base station in response.

In some embodiments, the user equipment is further configured to perform any of the user equipment methods described above.

Other embodiments include a computer program comprising instructions which, when executed on a processor of a user equipment, cause the processor to carry out any of the user equipment methods described above.

Yet other embodiments include a carrier containing the base station computer program or the user equipment computer program described above. The carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

Other embodiments are more fully described below with respect to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of embodiments of the technique are described with reference to the enclosed drawings, wherein:

Fig. 1 shows a schematic block diagram of an embodiment of a device for reporting a clear channel assessment (CCA) of a shared radio channel;

Fig. 2 shows a schematic block diagram of an embodiment of a device for triggering or receiving a clear channel assessment (CCA) of a shared radio channel;

Fig. 3 shows a flowchart for a method of reporting a clear channel assessment (CCA) of a shared radio channel, which method may be implementable by the device of Fig. 1 ;

Fig. 4 shows a flowchart for a method of triggering or receiving a clear channel assessment (CCA) of a shared radio channel, which method may be implementable by the device of Fig. 2;

Fig. 5 shows an exemplary network environment for implementing any of the devices of Figs. 1 and 2; Fig. 6 schematically illustrates a time period for a channel access mechanism, which may be implementable with any embodiment;

Fig. 7 schematically illustrates a signaling diagram resulting from embodiments of the devices of Figs. 1 and 2 performing implementations of the methods of Figs. 3 and 4, respectively, in radio communication;

Fig. 8 schematically illustrates a signaling diagram resulting from further embodiments of the devices of Figs. 1 and 2 performing further implementations of the methods of Figs. 3 and 4, respectively, in radio communication;

Fig. 9 schematically illustrates a signaling diagram for an aperiodic reporting of channel state information (CSI), which may be implementable in the methods of Figs. 3 and 4;

Fig. 10 schematically illustrates a timeline diagram resulting from still further embodiments of the devices of Figs. 1 and 2 performing still further implementations of the methods of Figs. 3 and 4, respectively;

Fig. 11 schematically illustrates a timeline diagram resulting from embodiments of the devices of Figs. 1 and 2 performing implementations of the methods of Figs. 3 and 4, respectively, using the aperiodic reporting of CSI;

Fig. 12 schematically illustrates a timeline diagram resulting from a group of embodiments of the device of Fig. 1 and an embodiment of the device of Fig. 2 performing implementations of the methods of Figs. 3 and 4, respectively;

Fig. 13 shows a schematic block diagram of a radio device embodying the device of Fig. 1 or Fig. 2;

Fig. 14 shows a schematic block diagram of a base station embodying the device of Fig. 2 or Fig. 1 ;

Fig. 15 schematically illustrates an example telecommunication network connected via an intermediate network to a host computer;

Fig. 16 shows a generalized block diagram of a host computer communicating via a base station or radio device functioning as a gateway with a user equipment over a partially wireless connection; and

Figs. 17 and 18 show flowcharts for methods implemented in a communication system including a host computer, a base station or radio device functioning as a gateway and a user equipment.

Fig. 19 is a flow diagram illustrating an example method implemented by a base station according to one or more embodiments of the present disclosure.

Fig. 20 is a flow diagram illustrating an example method implemented by a user equipment according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as a specific network environment in order to provide a thorough understanding of the technique disclosed herein. It will be apparent to one skilled in the art that the technique may be practiced in other embodiments that depart from these specific details. Moreover, while the following embodiments are primarily described for a New Radio (NR) or 5G implementation, it is readily apparent that the technique described herein may also be implemented for any other radio communication technique, including a Wireless Local Area Network (WLAN) implementation according to the standard family IEEE 802.11 , 3GPP LTE (e.g., LTE-Advanced or a related radio access technique such as MulteFire), for Bluetooth according to the Bluetooth Special Interest Group (SIG), particularly Bluetooth Low Energy, Bluetooth Mesh Networking and Bluetooth broadcasting, for Z-Wave according to the Z-Wave Alliance or for ZigBee based on IEEE 802.15.4.

Moreover, those skilled in the art will appreciate that the functions, steps, units and modules explained herein may be implemented using software functioning in conjunction with a programmed microprocessor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP) or a general-purpose computer, e.g., including an Advanced RISC Machine (ARM). It will also be appreciated that, while the following embodiments are primarily described in context with methods and devices, the invention may also be embodied in a computer program product as well as in a system comprising at least one computer processor and memory coupled to the at least one processor, wherein the memory is encoded with one or more programs that may perform the functions and steps or implement the units and modules disclosed herein.

Fig. 1 schematically illustrates a block diagram of an embodiment of a device for reporting a clear channel assessment (CCA) of a radio channel between a data transmitter and a data receiver for receiving data on the channel that is shared according to a channel access mechanism. The device is generically referred to by reference sign 100.

The device 100 optionally comprises a trigger module 102 for performing the step 202 of the first method aspect.

The device 100 comprises a CCA module 104 for performing the step 204 of the first method aspect, and a report result module 106 for performing the step 206 of the first method aspect.

Any of the modules of the device 100 may be implemented by units configured to provide the corresponding functionality.

The device 100 may also be referred to as, or may be embodied by, the data receiver (or briefly: receiver). The receiver 100 and the data transmitter may be in direct radio communication, e.g., at least for the shared channel. The data transmitter may be embodied by the device 200.

Fig. 2 schematically illustrates a block diagram of an embodiment of a device for triggering and/or receiving a clear channel assessment (CCA) of a radio channel between a data transmitter and a data receiver for transmitting data on the channel that is shared according to a channel access mechanism. The device is generically referred to by reference sign 200.

The device 200 optionally comprises a trigger module 202 for performing the step 402 of the second method aspect.

The device 200 comprises a CCA module 204 for performing the step 404 of the second method aspect, and a report result module 206 for performing the step 406 of the second method aspect.

Any of the modules of the device 200 may be implemented by units configured to provide the corresponding functionality.

The device 200 may also be referred to as, or may be embodied by, the data transmitter (or briefly: transmitter). The transmitter 200 and the data receiver may be in direct radio communication, e.g., at least for the shared channel. The data receiver may be embodied by the device 100.

Fig. 3 shows a flowchart for an example method 300. In some embodiments, the method 300 comprises receiving, at a data receiver 100, a trigger signal for performing a CCA of a radio channel between a data transmitter 200 and the data receiver 100 for receiving data on the channel that is shared according to a channel access mechanism (step 302). The method 300 additionally or alternatively comprises performing, responsive to the received trigger signal, the CCA of the channel at the data receiver 100 (step 304). The method 300 further comprises reporting a result of the CCA to the data transmitter 200 (step 306).

The method 300 may be performed by the device 100. For example, the modules 102, 104 and 106 may perform the steps 302, 304 and 306, respectively.

Fig. 4 shows a flowchart for another example method 400. In some embodiments, the method 400 comprises transmitting, to a data receiver 100, a trigger signal for performing a CCA of a radio channel between a data transmitter 100 and the data receiver 200 for transmitting data on the channel that is shared according to a channel access mechanism (step 402). The method 400 additionally or alternatively comprises transmitting (e.g., in association with the trigger signal) a measurement signal on the channel to the data receiver 200 for the CCA (step 404). The method 400 further comprises receiving a result of the CCA at the data transmitter (step 406).

The method 400 may be performed by the device 200. For example, the modules 202, 204 and 206 may perform the steps 402, 404 and 406, respectively.

In any aspect, the technique may be applied to uplink (UL), downlink (DL) or direct communications between radio devices, e.g., device-to-device (D2D) communications or sidelink (SL) communications.

Each of the transmitting station 100 and receiving station 200 may be a radio device or a base station. Herein, any radio device may be a mobile or portable station and/or any radio device wirelessly connectable to a base station or RAN, or to another radio device. For example, the radio device may be a user equipment (UE), a device for machine-type communication (MTC) or a device for (e.g., narrowband) Internet of Things (loT). Two or more radio devices may be configured to wirelessly connect to each other, e.g., in an ad hoc radio network or via a 3GPP SL connection. Furthermore, any base station may be a station providing radio access, may be part of a radio access network (RAN) and/or may be a node connected to the RAN for controlling the radio access. For example, the base station may be an access point, for example a Wi-Fi access point.

Herein, whenever referring to noise or a signal-to-noise ratio (SNR), a corresponding step, feature or effect is also disclosed for noise and/or interference or a signal-to-interference-and-noise ratio (SINR).

Any of the embodiments may share spectrum (i.e., using the shared channel), e.g., in a scenario and model for NR systems.

Fig. 5 schematically illustrates a spectrum sharing scenario between two NR systems 500.

As shown in Fig. 5, there are two NR networks (illustrated in black color for network A and in white color for network B). They are located in the same area and operate on the same channel or same frequency. The technique may be implemented for interference avoidance to make the network coexistence possible.

The devices 100 and 200 may be implemented by radio devices (i.e., UEs) 1300 or network nodes (i.e., base stations or access nodes, AN) 1400.

The channel access mechanism may be a Listen-before-talk (LBT), e.g., as specified for Wi-Fi systems.

Wi-Fi is a popular technology that allows an electronic device to exchange data wirelessly over a computer network, including high-speed Internet connections. Wi-Fi systems are the wireless local area network (WLAN) products that are based on IEEE 802.11 standards.

Fig. 6 schematically illustrates a Listen-Before-Talk (LBT) mechanism according to the standard IEEE 802.11.

As shown in Fig. 6, IEEE 802.11 employs a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)-based medium access control (MAC). The same protocol is applied by all stations (as an umbrella term for the devices 100 and 200), including the access point 1400, i.e., in both downlink (DL) and uplink (UL).

A station that wishes to transmit a packet first senses the medium. If the medium is sensed idle for a certain minimum time, a so-called Distributed Inter Frame Space 606 (DIFS, 50 ps for IEEE 802.11b), the packet (i.e., the data) is transmitted. If the medium (i.e., the shared channel) is busy, the station first defers until the medium is sensed idle. When this occurs, the station does not transmit immediately, which would lead to collisions if more than one station was deferring.

Instead, the station sets a backoff timer to a random number and does not transmit until this timer has expired. The backoff timer is only decreased when the medium is sensed idle, whereas whenever the medium is sensed busy, a deferral state is entered where the backoff timer is not decreased. When the backoff timer 608 expires, the packet is transmitted. If the packet is successfully received, the receiver 100 responds with an acknowledgement (ACK) to the transmitter 200. The acknowledgement is sent a Short Inter Frame Space 604 (SIFS, 10 ps for IEEE 802.11b) after the data frame is received. Since SIFS < DIFS, no other device 100 or 200 accesses the medium (i.e., the shared channel) during this time.

If no acknowledgement is received, either because the packet itself or the acknowledgement was lost, the transmitter 200 generates a new backoff, and retransmits the packet when the backoff timer has expired.

Even if the packet was successfully acknowledged, the transmitter 200 must generate a backoff and wait for it to expire before transmitting the next packet. To avoid congestion, when collisions occur, backoff values are drawn from distributions with larger and larger expectations for every retransmission attempt. The backoff time is measured in units of slot times, which for IEEE 802.11b are 20 ps (i.e., 20 microseconds) long.

Since current Wi-Fi systems are operating in low frequency (e.g., below 7 GHz), listen and talk are both omni-directional. The key objective of listen before talk (LBT) is to avoid interference between simultaneous data transmission. Practical application results show that this works well in this case.

Any embodiment may use directional transmission and reception of the data on the shared channel, e.g., in high frequency bands.

As the operating frequency of wireless networks increases and moves to a millimeter-wave (abbreviated by mmWave and mmW) in the frequency domain, data transmission between nodes suffers from high propagation loss, which is proportional to the square of the carrier frequency. Moreover, a millimeter-wave signal also suffers from high penetration loss and a variety of blockage problems.

On the other hand, with the wavelength as small as less than a centimeter, it becomes possible to pack a large number (e.g., tens, hundreds or even thousands) of antenna elements into a single antenna array with a compact formfactor, which can be widely adopted in access points and user devices. Such antenna arrays/panels can generate narrow beams with high beam forming gain to compensate for the high path loss in mmW communications, as well as providing highly directional transmission and reception pattern.

As a consequence, directional transmission and reception are the distinguishing characteristics for wireless networks in millimeter bands.

The technique may implement a receiver-assisted LBT.

In the classical LBT mechanism the transmitter is responsible for channel sensing before transmission. Only if the channel is sensed idle for a certain amount of time can the transmitter start to transmit the packet. This is motivated by the assumption that the interference level at the intended receiver is similar to the energy level detected at the transmitter. However, this assumption might not be justified in high frequency bands where the transmitter does not hear the same level of interference as the receiver, mainly due to large path loss at high frequency and directional transmission and reception pattern from large antenna array.

In one example when the transmitter is unable to hear the potential interferer at the receiver, it can decide to transmit the data packet, which results in collision at the receiver in the end. In another example, the potential transmitter overhears an ongoing transmission and refrains from its own transmission although its transmission would have not interfered with the ongoing transmission at the receiver. The former phenomenon is called “the hidden node problem” and the latter is known as “the exposed node problem”. Both hidden node and exposed node problems become more severe in unlicensed spectrum access in high frequency bands due to large path loss and directional transmission and reception.

The technique can be embodied as a channel access mechanism for channel sensing (i.e., the CCA) at the receiver 100, e.g., in unlicensed spectrum in high frequency bands.

In contrast to the classical LBT, in which channel sensing is carried out by the transmitter, the mechanism involves channel sensing on the receiver side, so as to obtain more accurate channel status for channel access. The technique may be implemented using a fast feedback request in the steps 306 and 406, and a report mechanism in the context of NR-U technology for the step 306 and 406.

Fig. 7 and Fig. 8 illustrate Receiver-Assisted LBT in NR DL and UL data transmission.

Fig. 7 schematically illustrates a downlink data transmission with receiver-assisted directional channel sensing as the CCA 304 and 404. Fig. 8 schematically illustrates an uplink data transmission with receiver-assisted directional channel sensing as the CCA 304 and 404.

Any embodiment of the technique may use aperiodic reporting of channel state information (CSI), e.g., for the triggering 302, the measuring 304 and the reporting 306.

The current NR specification supports aperiodic CSI reporting on PUSCH. The gNB 200 pre-configures the UE 100 with a list of aperiodic trigger states, with each of the trigger states linked to one or multiple associated report configurations. Each associated report configuration contains a CSI report configuration ID and specifies a set of resource sets of CSI reference signals (CSI-RS) for channel measurement and/or for interference measurement. The resource set of the CSI-RS may comprise resource sets of at least one of a non-zero-power CSI-RS (NZP CSI-RS), a synchronization signal block (SSB), and a CSI Interference Measurement (CSI-IM).

In the current NR specification, an aperiodic CSI is triggered by an UL grant DCI (DCI format 0-1 or 0-2). The CSI request value in triggering DCI points to one of the trigger states in the pre-configured aperiodic trigger state list. When the UE detects a UL grant DCI with a valid CSI Request value, the UE should perform channel and optional interference measurement based on the CSI resource sets specified in the pre-configured associated report configuration, compute CSI-related, L1-RSRP-related or L1-SINR-related quantities as specified in the CSI report configuration, and transmit CSI report on the PUSCH resource scheduled by the UL grant DCI. Fig. 9 briefly depicts the aperiodic CSI reporting procedure as specified in the current NR standard for the case of aperiodic CSI-RS. In Fig. 9, X represents the aperiodicTriggeringOffset given in NZP CSI-RS resource set; Y represents report slot offset determined by the triggering DCI and the reportSlotOffsetList in the CSI report configuration.

In NR Rel-15 and Rel-16, Aperiodic CSI reporting can only be triggered by UL grant DCIs and the CSI report can only be transmitted on PUSCH. An enhancement is currently being discussed in Rel-17 to support triggering Aperiodic CSI by a PDSCH scheduling DCI, i.e., DCI format 1_1 and 1_2. Since there is no associated PUSCH, the triggered Aperiodic CSI report is carried by PUCCH.

The Aperiodic CSI mechanism can be considered as some sort of aperiodic CSI reporting on PUCCH, which is built on the Aperiodic CSI reporting framework as specified in the current NR specification, mainly with the following enhancement:

Firstly, the aperiodic CSI is triggered by a DL DCI (DCI format 1-1 or 1-2). The DCI carries a CSI request, pointing to a pre-configured aperiodic CSI trigger state.

Secondly, the CSI report is transmitted on PUCCH. The PUCCH resource for CSI report transmission can be specified by higher layer configuration (CSI-ReportConfig).

More detailed information about Aperiodic CSI on PUCCH is described in the 3GPP document R1-2007708, "CSI Feedback Enhancements for lloT/URLLC", Ericsson, 3GPP TSG- RAN WG1 Meeting #103-e, October 26th - November 13th 2020.

Any aspect and any embodiment in the embodiments described herein may be implemented independently or in combination with any of the below described detailed embodiments.

In view of the above, Figure 19 illustrates an example method 700 implemented by a base station in a wireless communication network. The method 700 comprises transmitting, to a user equipment and on a downlink control channel, a trigger signal that triggers the user equipment to assess a shared channel (block 702). The trigger signal also configures the user equipment with radio resources of an uplink channel with which to report a result of the assessment. The method 700 further comprises receiving, on the radio resources of the uplink channel, the report of the result of the assessment performed by the user equipment (block 704). The method 700 further comprises transmitting data on the shared channel to the user equipment (block 706). The transmitting of the data is based on the result of the assessment performed by the user equipment.

Figure 20 illustrates an example method 800 implemented by a user equipment in a wireless communication network. The method 800 comprises receiving, from a base station and on a downlink control channel, a trigger signal that triggers the user equipment to assess a shared channel (block 802). The trigger signal also configures the user equipment with radio resources of an uplink channel with which to report a result of the assessment. The method 800 further comprises assessing the shared channel in response to the trigger signal (block 804). The method 800 further comprises transmitting, on the radio resources of the uplink channel, the report of the result of the assessment and receiving data on the shared channel from the base station in response (block 806).

The various embodiments of the present disclosure may be implemented in a variety of ways. Specific non-limiting examples will therefore be provided that provide additional or alternative steps to these methods 700, 800.

Detailed Embodiment 1

In a Receiver-Assisted LBT procedure (i.e., an implementation of the method 400), the gNB 200 triggers the UE 100 to report the interference situation at the UE side. As a non-limiting example, the gNB 200 transmits 402 the trigger signal (briefly: trigger) via PDCCH, which triggers the UE 100 to do channel sensing and/or channel measurement and report the result back to the gNB. The UE senses and/or measures the interference on the channel by detecting the received energy and/or measure signal and interference power levels, e.g., respectively.

In one variant of detailed embodiment 1 , the UE 100 reports only a success and/or a failure (also referred to as a state), if the detected energy level, and/or signal power, and/or interference power, and/or SINR are higher than a certain threshold. In another variant, the UE 100 reports the measured quantity.

The UE 100 reports the results via PUCCH.

In one variant, as a non-limiting exemplary implementation of the detailed embodiment 1 , the CCA report is a 1-bit value representing CCA success or failure. In another non-limiting exemplary implementation of the detailed embodiment 1 , the CCA report is a multi-bit value representing the RSRP or SINR level of the channel perceived by the UE.

In another variant of the embodiment, the CCA report is transmitted on PUCCH as a dedicated UCI type, re-using the legacy UCI on PUCCH transmission mechanism. In another variant of the embodiment, the CCA report is transmitted on PUCCH by re-interpreting some information bits in legacy UCI types, such as SR, HARQ-ACK or CSI.

As another aspect of the detailed embodiment 1 , the UE 100 reports the result in a form of preconfigured/fixed L1 signal/channel. As a non-limiting example, if the CCA succeeds, the UE 100 transmits 306 DMRS-only as an indication that the channel is clear. For example, PUCCH format 2, 3, or, 4 could be transmitted with only the REs allocated for DMRS occupied. The REs allocated to carry UCI would be empty.

As another aspect of the detailed embodiment 1, the UE 100 only reports when the CCA succeeds, and discard the report, otherwise.

In another variation, if CCA fails, a "reserved" value indicating "invalid" or "out-of-range" is indicated.

An example of PDCCH-triggered receiver channel sensing and CCA reporting on PUCCH is shown in Fig. 10. In another example, the channel sensing delay and the channel sensing window are not explicitly specified. Only the timing of the CCA report (i.e., reporting delay) is indicated by the gNB via L1 signaling or preconfigured via RRC signaling. In this case, the gNB needs to ensure the reporting delay is long enough for UE to decode the PDCCH, perform channel sensing and prepare the CCA report.

Fig. 10 schematically illustrates a timeline for the detailed embodiment 1 or an example of PDCCH-triggered channel sensing and CCA reporting via PUCCH.

Detailed Embodiment 1a

In one exemplary implementation of the teaching, upon detection of the PDCCH, the UE measures the energy on the wireless channel, in a similar way as Energy Detection (ED) in a classical LBT procedure. If the detected energy is less than a certain threshold, UE should report LBT success with the designated PUCCH resource, otherwise the UE should report LBT failure or skip the CCA reporting. The ED threshold can be fixed and specified in the specification, or preconfigured by the gNB via broadcasting or dedicated higher layer signaling.

The UE 100 should perform energy detection on one or multiple wireless channels (LBT bandwidths). In one non-limiting example, the wireless channel(s) for energy detection are specified in the specification. In another non-limiting example, the wireless channel(s) can be indicated in the DCI that triggers the channel sensing, or pre-configured by the gNB via broadcasting or dedicated higher layer signaling, or a combination of both indication in DCI and higher layer configuration.

The UE 100 may be instructed to perform energy detection in a certain time window, which can be specified in terms of channel sensing delay (in number of OFDM symbols or absolute time unit) and window size (in number of OFDM symbols, CCA slots or absolute time unit). In one nonlimiting example, the time window for energy detection is specified in the specification. In another non-limiting example, the time window can be indicated in the DCI that triggers the channel sensing, or pre-configured by the gNB via broadcasting or dedicated higher layer signaling, or a combination of both indication in DCI and higher layer configuration.

Detailed Embodiment 1b

In another exemplary implementation of the teaching, upon detection of the PDCCH, the UE 100 measures 304 the RSSI or RSRP of the PDCCH transmission based on the PDCCH DMRS symbols and/or data symbols. If the detected RSSI or RSRP is above a certain threshold, UE should report LBT success with the designated PUCCH resource, otherwise the UE should report LBT failure or skip the CCA reporting. The RSSI or RSRP threshold can be specified in the specification, or pre-configured by the gNB via broadcasting or dedicated higher layer signaling.

In another variant of the detailed embodiment 1 , the UE 100 may report RSSI or RSRP measurement result in the CCA as described in detailed embodiment 1.

In a non-limiting example, PDCCH DMRS symbols are used to perform channel and interference measurement in a 2-step process:

In a first process step, the channel is estimated (i.e., channel estimation is performed) from the PDCCH DMRS In a second process step, with knowledge of the received power from the serving gNB and the known DMRS, subtract off that part of the received signal due to the serving gNB, thus leaving interference as the result of the CCA.

Optionally in addition, the PDCCH data symbols can also be used to improve channel and interference measurement accuracy. After successfully decodes a PDCCH, the UE can reconstruct the PDCCH data symbols. Comparing the re-constructed data symbols with the corresponding received symbols, the UE can collect a much larger amount of channel samples and improve the channel estimation (and hence signal and interference power estimation) accuracy.

Detailed Embodiment 1c

In yet another exemplary implementation of the teaching, upon detection of the PDCCH, the UE measures signal and noise power and computes the SINR or RSRQ of the PDCCH transmission based on the DMRS symbols and/or data symbols. If the detected SINR or RSRQ is above a certain threshold, UE should report LBT success with the designated PUCCH resource, otherwise the UE should report LBT failure. The SINR or RSRQ threshold can be specified in the specification, or pre-configured by the gNB via broadcasting or dedicated higher layer signaling.

In another variant of the detailed embodiment 1 , the UE can report SINR or RSRQ measurement result in the CCA as described in detailed embodiment 1.

Detailed Embodiment 1d

In an exemplary implementation of the detailed embodiment 1 , a list of PUCCH resources (e.g., frequency, format, code and/or quasi-colocation, QCL) for CCA reporting 306 is preconfigured to the UE 100, e.g., via higher layer signaling.

The channel sensing triggering DCI in the step 302 may carry at least one of a PUCCH resource indicator pointing one of the pre-configured PUCCH resources that should be used for CCA reporting; and a relative time parameter specifying the PUCCH transmission time, with reference to the PDCCH transmission time.

The relative time parameter can indicate either the precise time at which the UE should transmit on PUCCH, or indicate that the PUCCH transmission should come at the first possible occasion after the indicated time.

When energy detection is used as the channel sensing method (i.e., in the CCA 304), the channel sensing triggering DCI might further carry at least one of a relative time parameter specifying the channel sensing delay, with reference to the PDCCH transmission time; and a LBT bandwidth indicator specifying the LBT bandwidth(s) on which the UE should perform energy detection.

Detailed Embodiment 2

In this embodiment, the Receiver-Assisted LBT is implemented with the Aperiodic CSI on PUCCH mechanism as described above. In a Receiver-Assisted procedure, gNB 200 transmits a PDCCH to a targeted UE 100, which triggers the UE 100 to conduct a channel and interference measurement in the step 304. The gNB 200 also transmits corresponding NZP CSI-RS resource and/or SSB and/or schedule CSI-IM resource for the UE to perform channel and interference measurement in the step 304.

The resulting measurement report, which may be L1-RSRP, L1-SINR or a dedicated report quantity, is transmitted on PUCCH in the step 306.

An example of aperiodic CSI reporting on PUCCH is shown in Fig. 11.

Detailed Embodiment 2a

In an exemplary implementation of the teaching, upon detection of the PDCCH triggering an aperiodic CSI report, the UE performs channel and interference measurement based on PDCCH DMRS symbols and data symbols, and report L1-RSRP or L1-SINR. In this embodiment, the triggering PDCCH is used as a dedicated type of single-port CSI-RS resource for channel and interference measurement, in addition to the existing CSI-RS resource types, i.e., NZP CSI-RS, SSB, CSI-IM and ZP CSI-RS.

The methodology to perform channel and interference measurement based on PDCCH DRMS and data symbols is explained in detailed embodiment 1b.

Detailed Embodiment 2b

In another exemplary implementation of the technique, the gNB 200 schedules CSI-IM resource for interference measurement purpose in the CCA 304. Upon detection of the PDCCH triggering an aperiodic CSI report in the step 302, the UE 100 may perform interference measurement using the CSI-IM resource and report the result in the step 304. In this embodiment, a dedicated type of CSI report quantity, e.g., referred to as L1-RSSI, may be defined for UE interference reporting in the step 306.

For CSI-IM based L1-RSSI measurement, the CSI-IM resource does not need to be associated with any NZP CSI-RS or SSB resources. In addition, a CSI-IM pattern, e.g., pattern 2, may be defined. The pattern represents that all sub-carriers in a resource block are used for interference measurements.

If in addition, the frequency resources are configured to cover the full active bandwidth part, this will allow the UE to do a simpler time domain measurement, instead of a frequency domain measurement.

To further optimize the size of the L1-RSSI report a mapping from actual RSSI values (in dBm) can be defined. The mapping can for example be a set of thresholds defining nonoverlapping intervals. In the extreme case, the mapping is just two intervals, one above and one below a single threshold. This mapping corresponds to an ED threshold.

Detailed Embodiment 2c

In yet another exemplary implementation of the teaching, gNB transmits NZP CSI-RS and schedules CSI-IM resource together with the PDCCH triggering the channel measurement. The gNB transmits the NZP CSI-RS resource before the CSI-IM resource thus allowing more time for the channel measurement. The rational being that, the channel measurement is not as delay sensitive as the interference measurement, because the channel power is not expected to change as quickly as the interference power. This allows the interference measurement to be done as close in time before the reporting as possible.

Detailed Embodiment 3

In yet another exemplary implementation of the teaching, different UE processing times are defined for the channel and interference measurements when done on dedicated interference measurement resources (such as CSI-IM resources). The rational being that interference measurements on CSI-IM resources are simpler as no reference signal is used, but rather the UE 100 can rely on an energy measurement. This is in particular true for an RSSI measurement which can be done in the time domain.

Detailed Embodiment 4

In one variant of implementation, when the UEs 100 measure the channel power and interference power in some earlier time then sense the channel (LBT) in a time later, the CSI report could be based on both the earlier measurement powers and the later LBT (interference) power. UEs could use one or more of the following options.

In a first option, the UEs compare the LBT interference power with certain ED threshold, then only send measurement report if LBT interference power is less than the ED threshold.

In a second option, the UEs 100 compare certain combined (filtering) function of earlier measurement powers and later LBT interference power with certain threshold, then sending CSI report based on the comparison.

In a third option, the UEs 100 update the CSI report based on the later LBT interference power before sending the report.

Detailed Embodiment 5

In one variant of the embodiment, the channel sensing trigger could be sent to a group of UEs using group common PDCCH. Periodic CSI-RS resources (which may be omitted if the UEs 100 are configured to only sense channel or common CSI-RS resource were transmitted together with the common triggering) and/or PUCCH resources may be pre-configured for the UEs 100.

The UEs 100 send the sensing reports using one of the periodic resources (e.g., the first one satisfy trigger timing). The gNB 200 may schedule the UEs 100 based on reports from the UEs 100.

In one variant, the common trigger may include one or more of the following information:

A first piece of information is a timing T 1 that UEs 100 to sense and/or measure the channel in the step 304 and/or a timing T2 in which the UEs 100 are to send 306 the reports. UEs 100 will select the first periodic CSI-RS resources (after T1) for sensing/measuring and/or first periodic PUCCH resources (after T2) to send the reports. Or the timings T1 , T2 could be preconfigured, then UEs could implicit determine based on the time of common triggering transmission. A second piece of information is CSI report quantity, e.g., a sensing result (LBT only, no need CSI-RS measurement), CSI-RSSI, and/or CSI-SINR (which may need CSI-RS resource, more CSI report bits).

The pre-configured periodic PUCCH resources for CSI reporting may be based on an existing PUCCH resources for SR report, optimally with enhancement by reinterpreting UCI bits or introducing more bits.

Fig. 12 schematically illustrates an example of channel sensing as the CCA with a common trigger in the steps 302 and 402.

Detailed Embodiment 6

In another embodiment, the UEs 100 may be configured to perform channel sensing and transmit the LBT CSI reports without explicit channel sensing trigger. This UE-initiated CCA or CSI reporting informs the gNB about the UE-side channel condition and will aid gNBs to schedule the UE for DL and UL transmission.

In a non-limiting example of the embodiment, the UE-initiated CCA or CSI reporting can be implemented with the periodic CSI reporting mechanism in the current NR specification, in which the UE is configured to periodically perform channel and interference measurement and report the resulting CSI via PUCCH. The resulting measurement report can be CCA status, L1-RSRP, L1- SINR or a dedicated report quantity. The CCA or CSI report size, content and transmission methodology are similar to what is proposed in detailed embodiment 1 and 2.

This operation may be configured using dedicated RRC or system information broadcast messages.

The initiation by the UE 100 (or self-triggering) may apply at least one of the following criteria.

As a first criterion, the UEs 100 may sense the channel whenever the respective UE 100 expects DL data from the gNB 200 and/or send their sensing reports in a periodic PUCCH resource.

As a second criterion, the UEs 100 may perform the CCA in the step 304 and/or report the result (e.g., a CSI report) in the step 306 multiplexed with data in PUSCH in case otherwise the PUCCH transmission would have overlapped in time with a dynamically scheduled or semi- persistent PUSCH transmission.

In view of all of the above, according to a first method aspect, a method of reporting a clear channel assessment (CCA) of a radio channel is provided. The CCA is between a data transmitter and a data receiver for receiving data on the channel. The channel is shared according to a channel access mechanism. Optionally, the method comprises or initiates a step of receiving, at the data receiver, a trigger signal for performing the CCA of the channel access mechanism. The method comprises or initiates a step of performing, optionally responsive to the received trigger signal, the CCA of the channel at the data receiver. The method further comprises or initiates a step of reporting a result of the CCA to the data transmitter. The first method aspect may be implemented alone or in combination with any one of the embodiments discussed herein. In particular, the first method aspect may be implemented or performed by the data receiver.

Each aspect of the technique may be implemented as a receiver-assisted listen-before-talk (LBT) mechanism. Embodiments of the technique are preferably implemented for NR in unlicensed spectrum (NR-U) and/or for operation in mmWave bands.

Herein, the terms LBT mechanism and channel access mechanism may be interchangeable. The LBT mechanism or the channel access mechanism may be any radio protocol for accessing the channel based on the CCA.

In any embodiment, the CCA may comprise channel sensing (e.g., determining whether or not the channel is clear or available or unoccupied, and/or measuring an interference power) and/or channel measurement (e.g., determining a received signal strength and/or performing a channel estimate).

The channel access mechanism may be based on the reported result of the CCA, e.g., for receiver-assisted LBT (optionally in NR-U).

By reporting the result of the CCA to the data transmitter, the data transmitter may access the channel (e.g., selectively transmit the data) depending on the reported result, i.e., based on a state of the channel at the data receiver, in at least some embodiments. For example, the technique can be implemented as a distributed channel access mechanism without or with less hidden-node problems and exposed-node problems, especially when using beamforming.

As to a second method aspect, a method of triggering or receiving a clear channel assessment (CCA) of a radio channel is provided. The channel is between a data transmitter and a data receiver for transmitting data on the channel. The channel is shared according to a channel access mechanism. Optionally, the method comprises or initiates a step of transmitting, to the data receiver, a trigger signal for performing the CCA of the channel access mechanism or a configuration message for periodically performing the CCA. The method comprises or initiates a step of transmitting, optionally in association with the trigger signal, a measurement signal on the channel to the data receiver for the CCA. The method further comprises or initiates a step of receiving a result of the CCA at the data transmitter.

The second method aspect may be implemented alone or in combination with any one of the embodiments in the list of embodiments described herein. In particular, the second method aspect may be implemented by a receiver counterpart to a transmitter as discussed herein.

Fig. 13 shows a schematic block diagram for an embodiment of the device 100 or the device 200. The device 100 or 200 comprises processing circuitry, e.g., one or more processors 1304 for performing the method 300 or 400 and memory 1306 coupled to the processors 1304. For example, the memory 1306 may be encoded with instructions that implement at least one of the modules 102, 104 and 106 or at least one of the modules 202, 204 and 206. The one or more processors 1304 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 100, such as the memory 1306, data receiver functionality or data transmitter functionality. For example, the one or more processors 1304 may execute instructions stored in the memory 1306. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 100 being configured to perform the action.

As schematically illustrated in Fig. 13, the device 100 or 200 may be embodied by a radio device 1300, e.g., functioning as receiving UE 100 or transmitting UE 200. The UE 1300 comprises a radio interface 1302 coupled to the device 100 or the device 200 for radio communication with one or more base stations, e.g., functioning as a receiving base station 100 or a transmitting base station 200.

Fig. 14 shows a schematic block diagram for an embodiment of the device 100 or the device 200. The device 100 or 200 comprises processing circuitry, e.g., one or more processors 1404 for performing the method 300 or 400 and memory 1406 coupled to the processors 1404. For example, the memory 1406 may be encoded with instructions that implement at least one of the modules 202, 204 and 206 or at least one of the modules 102, 104 and 106.

The one or more processors 1404 may be a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and/or encoded logic operable to provide, either alone or in conjunction with other components of the device 200, such as the memory 1406, data receiver functionality or data transmitter functionality. For example, the one or more processors 1404 may execute instructions stored in the memory 1406. Such functionality may include providing various features and steps discussed herein, including any of the benefits disclosed herein. The expression "the device being operative to perform an action" may denote the device 200 being configured to perform the action.

As schematically illustrated in Fig. 14, the device 100 or 200 may be embodied by a base station 1400, e.g., functioning as a receiving gNB 100 or a transmitting gNB 200. The base station 1400 comprises a radio interface 1402 coupled to the device 100 or 200 for radio communication with one or more radio device, e.g., functioning as a transmitting UE 200 or a receiving UE 100.

With reference to Fig. 15, in accordance with an embodiment, a communication system 1500 includes a telecommunication network 1510, such as a 3GPP-type cellular network, which comprises an access network 1511 , such as a radio access network, and a core network 1514.

The access network 1511 comprises a plurality of base stations 1512a, 1512b, 1512c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1513a, 1513b, 1513c. Each base station 1512a, 1512b, 1512c is connectable to the core network 1514 over a wired or wireless connection 1515. A first user equipment (UE) 1591 located in coverage area 1513c is configured to wirelessly connect to, or be paged by, the corresponding base station 1512c. A second UE 1592 in coverage area 1513a is wirelessly connectable to the corresponding base station 1512a. While a plurality of UEs 1591 , 1592 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 1512.

Any of the base stations 1512 and the UEs 1591 , 1592 may embody the device 100.

The telecommunication network 1510 is itself connected to a host computer 1530, 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. The host computer 1530 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. The connections 1521 , 1522 between the telecommunication network 1510 and the host computer 1530 may extend directly from the core network 1514 to the host computer 1530 or may go via an optional intermediate network 1520. The intermediate network 1520 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1520, if any, may be a backbone network or the Internet; in particular, the intermediate network 1520 may comprise two or more sub-networks (not shown).

The communication system 1500 of Fig. 15 as a whole enables connectivity between one of the connected UEs 1591 , 1592 and the host computer 1530. The connectivity may be described as an over-the-top (OTT) connection 1550. The host computer 1530 and the connected UEs 1591 , 1592 are configured to communicate data and/or signaling via the OTT connection 1550, using the access network 1511 , the core network 1514, any intermediate network 1520 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1550 may be transparent in the sense that the participating communication devices through which the OTT connection 1550 passes are unaware of routing of uplink and downlink communications. For example, a base station 1512 need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 1530 to be forwarded (e.g., handed over) to a connected UE 1591. Similarly, the base station 1512 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1591 towards the host computer 1530.

By virtue of the method 300 or 400 being performed by any one of the UEs 1591 or 1592 and/or any one of the base stations 1512, the performance or range of the OTT connection 1550 can be improved, e.g., in terms of increased throughput and/or reduced latency. More specifically, the host computer 1530 may indicate to the RAN 500 or the device 100 or 200 (e.g., on an application layer) to use the shared channel. 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. 16. In a communication system 1600, a host computer 1610 comprises hardware 1615 including a communication interface 1616 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1600. The host computer 1610 further comprises processing circuitry 1618, which may have storage and/or processing capabilities. In particular, the processing circuitry 1618 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. The host computer 1610 further comprises software 1611 , which is stored in or accessible by the host computer 1610 and executable by the processing circuitry 1618. The software 1611 includes a host application 1612. The host application 1612 may be operable to provide a service to a remote user, such as a UE 1630 connecting via an OTT connection 1650 terminating at the UE 1630 and the host computer 1610. In providing the service to the remote user, the host application 1612 may provide user data, which is transmitted using the OTT connection 1650. The user data may depend on the location of the UE 1630. The user data may comprise auxiliary information or precision advertisements (also: ads) delivered to the UE 1630. The location may be reported by the UE 1630 to the host computer, e.g., using the OTT connection 1650, and/or by the base station 1620, e.g., using a connection 1660.

The communication system 1600 further includes a base station 1620 provided in a telecommunication system and comprising hardware 1625 enabling it to communicate with the host computer 1610 and with the UE 1630. The hardware 1625 may include a communication interface 1626 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1600, as well as a radio interface 1627 for setting up and maintaining at least a wireless connection 1670 with a UE 1630 located in a coverage area (not shown in Fig. 16) served by the base station 1620. The communication interface 1626 may be configured to facilitate a connection 1660 to the host computer 1610. The connection 1660 may be direct, or it may pass through a core network (not shown in Fig. 16) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1625 of the base station 1620 further includes processing circuitry 1628, 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. The base station 1620 further has software 1621 stored internally or accessible via an external connection.

The communication system 1600 further includes the UE 1630 already referred to. Its hardware 1635 may include a radio interface 1637 configured to set up and maintain a wireless connection 1670 with a base station serving a coverage area in which the UE 1630 is currently located. The hardware 1635 of the UE 1630 further includes processing circuitry 1638, 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. The UE 1630 further comprises software 1631 , which is stored in or accessible by the UE 1630 and executable by the processing circuitry 1638. The software 1631 includes a client application 1632. The client application 1632 may be operable to provide a service to a human or non-human user via the UE 1630, with the support of the host computer 1610. In the host computer 1610, an executing host application 1612 may communicate with the executing client application 1632 via the OTT connection 1650 terminating at the UE 1630 and the host computer 1610. In providing the service to the user, the client application 1632 may receive request data from the host application 1612 and provide user data in response to the request data. The OTT connection 1650 may transfer both the request data and the user data. The client application 1632 may interact with the user to generate the user data that it provides.

It is noted that the host computer 1610, base station 1620 and UE 1630 illustrated in Fig. 16 may be identical to the host computer 1530, one of the base stations 1512a, 1512b, 1512c and one of the UEs 1591 , 1592 of Fig. 15, respectively. This is to say, the inner workings of these entities may be as shown in Fig. 16, and, independently, the surrounding network topology may be that of Fig. 15.

In Fig. 16, the OTT connection 1650 has been drawn abstractly to illustrate the communication between the host computer 1610 and the UE 1630 via the base station 1620, 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 the UE 1630 or from the service provider operating the host computer 1610, or both. While the OTT connection 1650 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).

The wireless connection 1670 between the UE 1630 and the base station 1620 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 the UE 1630 using the OTT connection 1650, in which the wireless connection 1670 forms the last segment. More precisely, the teachings of these embodiments may reduce the latency and improve the data rate and thereby provide benefits such as better responsiveness and improved QoS.

A measurement procedure may be provided for the purpose of monitoring data rate, latency, QoS and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1650 between the host computer 1610 and UE 1630, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1650 may be implemented in the software 1611 of the host computer 1610 or in the software 1631 of the UE 1630, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1650 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 1611 , 1631 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1650 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 1620, and it may be unknown or imperceptible to the base station 1620. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer’s 1610 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 1611 , 1631 causes messages to be transmitted, in particular empty or "dummy" messages, using the OTT connection 1650 while it monitors propagation times, errors etc.

Fig. 17 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. 15 and 16. For simplicity of the present disclosure, only drawing references to Fig. 17 will be included in this paragraph. In a first step 1710 of the method, the host computer provides user data. In an optional substep 1711 of the first step 1710, the host computer provides the user data by executing a host application. In a second step 1720, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 1730, 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 an optional fourth step 1740, the UE executes a client application associated with the host application executed by the host computer.

Fig. 18 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. 15 and 16. For simplicity of the present disclosure, only drawing references to Fig. 18 will be included in this paragraph. In a first step 1810 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 a second step 1820, 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 an optional third step 1830, the UE receives the user data carried in the transmission.

As has become apparent from above description, at least some embodiments of the technique allow implementing a receiver-assisted LBT mechanism. Same or further embodiments allow any other receiver-assisted interference management schemes, e.g., in NR with low cost and minimum impact on the technical specification. Any aspect of the technique may be an implementation of receiver-assisted interference management, e.g., in the context of current or future 3GPP specifications for NR. More specifically, embodiments allow performing channel sensing and/or channel measurement in the CCA, and reporting, e.g., based on specific reference channels and signals in the receiver-assisted LBT for unlicensed NR operation in mmWave bands.

The technique may be used, alternatively or in addition to LBT, for other kinds of interference management schemes that involve channel and interference measurement reporting from radio devices (e.g., UEs). For example, the shared channel may be a channel using multiple hierarchical layers that are transmitted simultaneously, wherein the sharing refers to the multiple hierarchical layers. For example, the mutual information of the channel may be shared between the multiple hierarchical layers.

Without limitation, for example in a 3GPP implementation, any "radio device" as described herein may be a user equipment (UE). Any "network node" or "base station" may be a next- generation Node B (gNodeB or gNB).

The technique may be applied in the context of 3GPP New Radio (NR).

The channel may be a sidelink (SL) between radio devices. Unlike a SL according to 3GPP LTE, a SL according to 3GPP NR can provide a wide range of QoS levels.

The technique may be implemented in accordance with a 3GPP specification, e.g., for 3GPP release 17. The technique may be implemented for 3GPP LTE or 3GPP NR according to a modification of the 3GPP document TS 23.303, version 16.0.0 or for 3GPP NR according to a modification of the 3GPP document TS 33.303, version 16.0.0.

In any radio access technology (RAT), the technique may be implemented for UL, DL or SL as the channel. The SL may be implemented using proximity services (ProSe), e.g., according to a 3GPP specification.

The data transmitter may be a radio device, e.g., user equipment (UE), optionally according to a 3GPP specification. Alternatively, the data transmitter may be a network node (e.g., a base station) of a radio access network (RAN), optionally according to a 3GPP specification.

The radio device and/or the network node and/or the RAN may form, or may be part of, a radio network, e.g., according to the Third Generation Partnership Project (3GPP) or according to the standard family IEEE 802.11 (Wi-Fi). Each of the first method aspect and the second method aspect may be performed by one or more embodiments of the radio device (e.g., a UE), the network node (e.g., a base station) or the RAN.

The RAN may comprise one or more base stations, e.g., performing the third method aspect. Alternatively or in addition, the radio network may be a vehicular, ad hoc and/or mesh network comprising two or more radio devices, e.g., acting as the remote radio device and/or the relay radio device and/or the further remote radio device.

Any of the radio devices may be a 3GPP user equipment (UE) or a Wi-Fi station (ST A). The radio device may be a mobile or portable station, a device for machine-type communication (MTC), a device for narrowband Internet of Things (NB-loT) or a combination thereof. Examples for the UE and the mobile station include a mobile phone, a tablet computer and a self-driving vehicle. Examples for the portable station include a laptop computer and a television set. Examples for the MTC device or the NB-loT device include robots, sensors and/or actuators, e.g., in manufacturing, automotive communication and home automation. The MTC device or the NB-loT device may be implemented in a manufacturing plant, household appliances and consumer electronics.

Whenever referring to the RAN, the RAN may be implemented by one or more base stations.

The data transmitter and the data receiver may be wirelessly connected or connectable (e.g., according to a radio resource control, RRC, state or active mode).

The base station may encompass any station that is configured to provide radio access to any of the radio devices. The base stations may also be referred to as cell, transmission and reception point (TRP), radio access node or access point (AP). The base station and/or the relay radio device may provide a data link to a host computer providing the user data to the remote radio device or gathering user data from the remote radio device. Examples for the base stations may include a 3G base station or Node B (NB), 4G base station or eNodeB (eNB), a 5G base station or gNodeB (gNB), a Wi-Fi AP and a network controller (e.g., according to Bluetooth, ZigBee or Z- Wave).

The RAN may be implemented according to the Global System for Mobile Communications (GSM), the Universal Mobile Telecommunications System (UMTS), 3GPP Long Term Evolution (LTE) and/or 3GPP New Radio (NR).

Any aspect of the technique may be implemented on a Physical Layer (PHY), a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a packet data convergence protocol (PDCP) layer, and/or a Radio Resource Control (RRC) layer of a protocol stack for the radio communication.

As to another aspect, a computer program product is provided. The computer program product comprises program code portions for performing any one of the steps of the first and/or second method aspect disclosed herein when the computer program product is executed by one or more computing devices. The computer program product may be stored on a computer-readable recording medium. The computer program product may also be provided for download, e.g., via the radio network, the RAN, the Internet and/or the host computer. Alternatively, or in addition, the method may be encoded in a Field-Programmable Gate Array (FPGA) and/or an Application- Specific Integrated Circuit (ASIC), or the functionality may be provided for download by means of a hardware description language.

Embodiments described herein include one or more devices configured to perform any one of the steps of the methods described herein.

As to a still further aspect a communication system including a host computer is provided. The host computer comprises a processing circuitry configured to provide user data, e.g., included in the data of the shared channel. The host computer further comprises a communication interface configured to forward the data to a radio and/or cellular network (e.g., the RAN and/or the base station acting as the data transmitter) for transmission to a UE (e.g., the data receiver). A processing circuitry of the cellular network is configured to execute any one of the steps of the first and/or second method aspects. The UE comprises a radio interface and processing circuitry, which is configured to execute any one of the steps of the first and/or second method aspects.

The communication system may further include the UE. Alternatively, or in addition, the cellular network may further include one or more base stations configured for radio communication with the UE and/or to provide a data link between the UE and the host computer using the first and/or second method aspects.

The processing circuitry of the host computer may be configured to execute a host application, thereby providing the data and/or any host computer functionality described herein. Alternatively, or in addition, the processing circuitry of the UE may be configured to execute a client application associated with the host application. Any one of the devices, the UE, the base station, the communication system or any node or station for embodying the technique may further include any feature disclosed in the context of the method aspect, and vice versa. Particularly, any one of the units and modules disclosed herein may be configured to perform or initiate one or more of the steps of the method aspect.

Many advantages of the present invention will be fully understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the units and devices without departing from the scope of the invention and/or without sacrificing all of its advantages.

Claims

CLAIMS What is claimed is:

1. A method (700), implemented by a base station (1400) in a wireless communication network, the method comprising: transmitting, to a user equipment (1300) and on a downlink control channel, a trigger signal that: triggers the user equipment (1300) to assess a shared channel; and configures the user equipment (1300) with radio resources of an uplink channel with which to report a result of the assessment; receiving, on the radio resources of the uplink channel, the report of the result of the assessment performed by the user equipment (1300); and transmitting data on the shared channel to the user equipment (1300), wherein the transmitting of the data is based on the result of the assessment performed by the user equipment (1300).

2. The method of claim 1 , wherein the trigger signal triggers the user equipment (1300) to perform a Clear Channel Assessment, CCA, or a channel measurement of the shared channel.

3. The method of claim 2, wherein the report comprises a one-bit flag indicating either success or failure of the CCA respectively representing whether or not a signal quality of the uplink channel is better than a quality threshold.

4. The method of any one of claims 1-2, wherein the report comprises a Received Signal Strength Indicator, a Reference Signal Received Power, a Signal-to-Noise Ratio, and/or a Signal- to-lnterference-and-Noise Ratio of the shared channel.

5. The method of any one of claims 1-4, wherein: the radio resources comprise a first portion allocated for a demodulation reference signal, DMRS, and a second portion allocated for corresponding Uplink Control Information, UCI; receiving the report of the result of the assessment on the radio resources comprises receiving an indication that the uplink channel is clear; receiving the indication that the uplink is clear comprises receiving the DMRS on the first portion of the resources and the second portion of the resources being empty.

6. The method of any one of claims 1-5, further comprising configuring the user equipment (1300) with a resource set, wherein the report of the result of the assessment indicates a measurement of the resource set taken by the user equipment (1300).

7. The method of claim 6, wherein the resource set comprises: time/frequency resources for aperiodic Channel State Information Reference Signal, CSI- RS, reporting; a bandwidth and a duration over which to perform the measurement of the resource set; a synchronization signal block; and/or a Channel State Information Interference Measurement, CSI-IM, resource.

8. The method of any one of claims 1 -7, wherein receiving the report of the result of the assessment comprises receiving the report of the result in an aperiodic Channel State Information, CSI, report.

9. The method of any one of claims 1-8, wherein transmitting the trigger signal comprises transmitting the trigger signal in an uplink grant.

10. A method (800), implemented by a user equipment (1300) in a wireless communication network, the method comprising: receiving, from a base station (1400) and on a downlink control channel, a trigger signal that: triggers the user equipment (1300) to assess a shared channel; and configures the user equipment (1300) with radio resources of an uplink channel with which to report a result of the assessment; assessing the shared channel in response to the trigger signal; transmitting, on the radio resources of the uplink channel, the report of the result of the assessment and receiving data on the shared channel from the base station (1400) in response.

11. The method of claim 10, wherein the trigger signal triggers the user equipment (1300) to perform a Clear Channel Assessment, CCA, or a channel measurement of the shared channel.

12. The method of claim 11 , wherein the report comprises a one-bit flag indicating either success or failure of the CCA respectively representing whether or not a signal quality of the uplink channel is better than a quality threshold.

13. The method of any one of claims 10-11 , wherein the report comprises a Received Signal Strength Indicator, a Reference Signal Received Power, a Signal-to-Noise Ratio, and/or a Signal- to-lnterference-and-Noise Ratio of the shared channel.

14. The method of any one of claims 10-13, wherein: the radio resources comprise a first portion allocated for a demodulation reference signal, DMRS, and a second portion allocated for corresponding Uplink Control Information, UCI; transmitting the report of the result of the assessment on the radio resources comprises transmitting an indication that the uplink channel is clear; transmitting the indication that the uplink is clear comprises transmitting the DMRS on the first portion of the resources and leaving the second portion of the resources empty.

15. The method of any one of claims 10-14, further comprising receiving a resource set from the base station (1400), wherein the report of the result of the assessment indicates a measurement of the resource set taken by the user equipment (1300).

16. The method of claim 15, wherein the resource set comprises: time/frequency resources for aperiodic Channel State Information Reference Signal, CSI- RS, reporting; a bandwidth and a duration over which to perform the measurement of the resource set; a synchronization signal block; and/or a Channel State Information Interference Measurement, CSI-IM, resource.

17. The method of any one of claims 10-16, wherein transmitting the report of the result of the assessment comprises transmitting the report of the result in an aperiodic Channel State Information, CSI, report.

18. The method of any one of claims 10-17, wherein receiving the trigger signal comprises receiving the trigger signal in an uplink grant.

19. A base station (1400) comprising: a processor (1404) and a memory (1406), the memory (1406) containing instructions executable by the processor (1404) whereby the base station (1400) is configured to: transmit, to a user equipment (1300) and on a downlink control channel, a trigger signal that: triggers the user equipment (1300) to assess a shared channel; and configures the user equipment (1300) with radio resources of an uplink channel with which to report a result of the assessment; receive, on the radio resources of the uplink channel, the report of the result of the assessment performed by the user equipment (1300); and transmit data on the shared channel to the user equipment (1300), wherein the transmitting of the data is based on the result of the assessment performed by the user equipment (1300).

20. The base station of the preceding claim, further configured to perform the method of any one of claims 2-9.

21. A computer program, comprising instructions which, when executed on a processor (1404) of a base station (1400), cause the processor (1404) to carry out the method according to any one of claims 1-9.

22. A user equipment (1300) comprising: a processor (1304) and a memory (1306), the memory (1306) containing instructions executable by the processor (1304) whereby the user equipment (1300) is configured to: receive, from a base station (1400) and on a downlink control channel, a trigger signal that: triggers the user equipment (1300) to assess a shared channel; and configures the user equipment (1300) with radio resources of an uplink channel with which to report a result of the assessment; assess the shared channel in response to the trigger signal; transmit, on the radio resources of the uplink channel, the report of the result of the assessment and receive data on the shared channel from the base station (1400) in response.

23. The user equipment of the preceding claim, further configured to perform the method of any one of claims 11-18.

24. A computer program, comprising instructions which, when executed on a processor (1304) of a user equipment (1300), cause the processor (1304) to carry out the method according to any one of claims 10-18.

25. A carrier containing the computer program of claim 21 or 24, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.