CN113056944B

CN113056944B - Method, apparatus and computer readable medium for communication

Info

Publication number: CN113056944B
Application number: CN201880099186.7A
Authority: CN
Inventors: 孙欢
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2018-10-31
Filing date: 2018-10-31
Publication date: 2024-03-26
Anticipated expiration: 2038-10-31
Also published as: WO2020087350A1; CN113056944A

Abstract

Embodiments of the present disclosure relate to a method, apparatus, and computer-readable medium for configuring a measurement gap pattern. In an example embodiment, the method includes selecting, at a first network device serving the terminal device, a second network device for cooperative downlink transmission to the terminal device; transmitting, to a terminal device on a downlink data channel, a resource allocation indication for downlink control information, DCI, and information regarding decoding of the DCI, the DCI being associated with a second network device; determining whether a link between the first network device and the second network device is an ideal backhaul link or a non-ideal backhaul link; in response to determining that the link is an ideal backhaul link, DCI is sent to the terminal device on at least a first downlink control channel between the first network device and the terminal device.

Description

Method, apparatus and computer readable medium for communication

Technical Field

Embodiments of the present disclosure relate generally to the field of telecommunications and, in particular, relate to methods, apparatuses, and computer-readable media for communication.

Background

In the Next Radio (NR) system, a cooperative (co-operating) transmission scheme of a plurality of Transmission and Reception Points (TRP) is studied to improve cell edge performance for a low frequency band and to provide high rank (high rank) transmission of a high and low frequency band in a line of sight (LOS) dominant transmission scenario. In order to trade-off the performance, complexity and backhaul link requirements of NR systems, a non-coherent joint transmission scheme (NCJT) is proposed. However, there remains a need to discuss details of downlink control channel transmissions and downlink data channel transmissions associated with NCJTs.

Disclosure of Invention

In general, example embodiments of the present disclosure provide methods, apparatus, and computer-readable media for communication.

In a first aspect, a communication method implemented at a first network device is provided. The method includes selecting, at a first network device serving the terminal device, a second network device for cooperative downlink transmission to the terminal device. The method also includes transmitting, to the terminal device, a resource allocation indication for Downlink Control Information (DCI) and information regarding decoding of the DCI on a downlink data channel, the DCI being associated with the second network device. The method also includes determining whether a link between the first network device and the second network device is an ideal backhaul or a non-ideal backhaul. The method further comprises the steps of: in response to determining that the link is an ideal backhaul, DCI is sent to the terminal device on at least a first downlink control channel between the first network device and the terminal device.

In some example embodiments, selecting a second network device for cooperative downlink transmission to a terminal device comprises: comparing a first quality of a first uplink channel between the second network device and the terminal device with a second quality of a second uplink channel between the third network device and the terminal device; in response to the first quality being higher than the second quality, sending an indication to the second network device of: initiating a measurement of a third quality of a downlink channel between the second network device and the terminal device; transmitting information about a pair of uplink beams associated with a first quality to a terminal device; receiving an indication of a third quality from the terminal device; and in response to determining that the third quality exceeds the first threshold quality, sending an indication to the second network device that the second network device is selected for cooperative downlink transmission to the terminal device.

In some example embodiments, transmitting the DCI includes: the DCI is transmitted in a predefined control region in a subframe.

In some example embodiments, transmitting DCI in a predefined control region includes: other DCI associated with the first network device is transmitted in a first sub-region of the predefined control region and DCI is transmitted in a second sub-region of the predefined control region, the second sub-region being subsequent to the first sub-region.

In some example embodiments, the size of the predefined control region is preconfigured.

In some example embodiments, the method further comprises: obtaining a quality of a channel between the first network device and the terminal device from the terminal device; comparing the quality of the channel with a second threshold quality; and determining a starting position of the second sub-region in the sub-frame based on the comparison.

In some example embodiments, determining the starting position of the second sub-region in the sub-frame comprises: determining a third symbol in the subframe as a starting position of the second sub-region in response to the quality of the channel exceeding a second threshold quality; and responsive to the quality of the channel being below a second threshold quality, determining a fourth symbol in the subframe as a starting position of the second sub-region.

In some example embodiments, transmitting the resource allocation indication includes: and sending a resource allocation indication indicating the starting position of the second sub-region.

In some example embodiments, transmitting other DCIs and DCIs includes: encoding other DCIs and DCIs by using a predetermined space-time block code (space-time block code) to obtain first encoded DCIs and second encoded DCIs; and transmitting the first coded DCI and the second coded DCI.

In some example embodiments, the method further comprises: in response to determining that the link is a non-ideal backhaul, a first indication is sent to the terminal device in a first subframe that a downlink transmission from the second network device is to be initiated.

In some example embodiments, transmitting the first indication includes: the first indication is sent in a control region in a first subframe.

In some example embodiments, transmitting the first indication includes: the first indication is sent in a data region in a first subframe.

In some example embodiments, the method further comprises: in response to receiving a positive acknowledgement indicating that the downlink transmission from the second network device is accepted, disabling transmission of the first indication in a second subframe subsequent to the first subframe.

In some example embodiments, the method further comprises: the first indication is sent in a third subframe subsequent to the first subframe in response to receiving a negative acknowledgement indicating that the downlink transmission from the second network device is denied.

In a second aspect, a communication method implemented at a first network device is provided. The method comprises the following steps: comparing a first quality of a first uplink channel between the second network device and a terminal device served by the first network device with a second quality of a second uplink channel between the third network device and the terminal device; in response to the first quality being higher than the second quality, sending an indication to the second network device of: initiating a measurement of a third quality of a downlink channel between the second network device and the terminal device; transmitting information about a pair of uplink beams associated with a first quality to a terminal device; receiving an indication of a third quality from the terminal device; and in response to determining that the third quality exceeds the first threshold quality, sending an indication to the second network device that the second network device is selected for cooperative downlink transmission to the terminal device.

In a third aspect, a method implemented at a terminal device is provided. The method comprises the following steps: receiving, on a downlink data channel between a first network device and a terminal device, a resource allocation indication for downlink control information, DCI, and information regarding decoding of the DCI, the DCI being associated with a second network device; and receiving DCI on a first downlink control channel in response to determining that the resource allocation indication indicates resources on the first downlink control channel between the first network device and the terminal device.

In some example embodiments, receiving DCI includes: the DCI is received in a predefined control region in a subframe.

In some example embodiments, receiving DCI in a predefined control region includes: other DCI associated with the first network device is received in a first sub-region of the predefined control region and DCI is received in a second sub-region of the predefined control region, the second sub-region being subsequent to the first sub-region.

In some example embodiments, the method further comprises: the quality of the channel between the first network device and the terminal device is transmitted to the first network device for determination of the starting position of the second sub-region in the sub-frame.

In some example embodiments, receiving the resource allocation indication includes: a resource allocation indication is received indicating a starting position of the second sub-region.

In some example embodiments, the starting position of the second sub-region is a third symbol in the subframe.

In some example embodiments, the starting position of the second sub-region is a fourth symbol in the subframe.

In some example embodiments, receiving other DCIs and DCIs includes: receiving first coded DCI and second coded DCI; and decoding the first encoded DCI and the second encoded DCI with a predetermined space-time block code to obtain other DCIs and DCIs.

In some example embodiments, the method further comprises: in response to determining that the resource allocation indication indicates resources on a second downlink control channel between the second network device and the terminal device, a first indication is received in a first subframe from the first network device that a downlink transmission from the second network device is to be initiated.

In some example embodiments, receiving the first indication includes: a first indication is received in a control region in a first subframe.

In some example embodiments, receiving the first indication includes: a first indication is received in a data region in a first subframe.

In some example embodiments, the method further comprises: determining, in response to success of decoding the first indication, whether the downlink transmission is acceptable; in response to determining that the downlink transmission is acceptable, sending a positive acknowledgement to the first network device indicating that the downlink transmission is acceptable; and in response to determining that the downlink transmission is unacceptable, sending a negative acknowledgement to the first network device indicating that the downlink transmission is denied.

In some example embodiments, the method further comprises: the first indication is received in a third subframe subsequent to the first subframe in response to sending a negative acknowledgement indicating that the downlink transmission was denied.

In some example embodiments, the method further comprises: transmitting a first uplink reference signal to the second network device for measurement of a first quality of a first uplink channel between the second network device and the terminal device; transmitting a second uplink reference signal to the third network device for measurement of a second quality of a second uplink channel between the third network device and the terminal device; in response to receiving information from the first network device regarding a pair of uplink beams associated with the first quality, performing a measurement of a third quality of a downlink channel between the second network device and the terminal device; and sending an indication of the third quality to the first network device for use in deciding on a cooperative downlink transmission from the first network device and the second network device to the terminal device.

In a fourth aspect, a communication method implemented at a second network device is provided. The method comprises the following steps: measuring, at the second network device, a first quality of a first uplink channel between the second network device and a terminal device served by the first network device; transmitting an indication of the first quality and information about a pair of uplink beams associated with the first quality to a first network device; transmitting, to the terminal device, a downlink reference signal for measurement in response to receiving an indication from the first network device to initiate measurement of quality of a downlink channel between the second network device and the terminal device; and receiving, from the first network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to the quality of the downlink channel exceeding a first threshold quality.

In some example embodiments, the method further comprises: the downlink transmission is initiated in response to receiving a positive acknowledgement from the terminal device indicating that the downlink transmission from the second network device is accepted.

In a fifth aspect, a first network device is provided. The first network device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to perform the method according to the first aspect.

In a sixth aspect, a first network device is provided. The first network device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to perform the method according to the second aspect.

In a seventh aspect, a terminal device is provided. The terminal device comprises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal device to perform the method according to the third aspect.

In an eighth aspect, a second network device is provided. The second network device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the second network device to perform the method according to the fourth aspect.

In a ninth aspect, a communication apparatus is provided. The device comprises: means for selecting, at a first network device serving the terminal device, a second network device for cooperative downlink transmission to the terminal device; means for transmitting, to a terminal device, a resource allocation indication for downlink control information, DCI, on a downlink data channel and information regarding decoding of the DCI, the DCI being associated with a second network device; means for determining whether a link between the first network device and the second network device is an ideal backhaul or a non-ideal backhaul; and means for transmitting DCI to the terminal device on at least a first downlink control channel between the first network device and the terminal device in response to determining that the link is an ideal backhaul.

In a tenth aspect, a communication device is provided. The device comprises: means for comparing a first quality of a first uplink channel between a second network device and a terminal device served by the first network device with a second quality of a second uplink channel between a third network device and the terminal device; means for sending, in response to the first quality being higher than the second quality, to the second network device an indication of: initiating a measurement of a third quality of a downlink channel between the second network device and the terminal device; means for transmitting information about a pair of uplink beams associated with a first quality to a terminal device; means for receiving an indication of a third quality from the terminal device; and means for sending, to the second network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to determining that the third quality exceeds the first threshold quality.

In an eleventh aspect, a communication apparatus is provided. The device comprises: means for receiving, on a downlink data channel between a first network device and a terminal device, a resource allocation indication for downlink control information, DCI, and information regarding decoding of the DCI, the DCI being associated with a second network device; and means for receiving DCI on a first downlink control channel in response to determining that the resource allocation indication indicates resources on the first downlink control channel between the first network device and the terminal device.

In a twelfth aspect, a communication device is provided. The device comprises: means for measuring, at the second network device, a first quality of a first uplink channel between the second network device and a terminal device served by the first network device; means for transmitting an indication of a first quality and information about a pair of uplink beams associated with the first quality to a first network device; means for transmitting a downlink reference signal for measurement to a terminal device in response to receiving an indication from a first network device to initiate measurement of quality of a downlink channel between a second network device and the terminal device; and means for receiving, from the first network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to the quality of the downlink channel exceeding a first threshold quality.

In a thirteenth aspect, a computer readable medium is provided on which a computer program is stored. The computer program, when executed by a processor, causes the processor to perform the method according to the first aspect.

In a fourteenth aspect, a computer readable medium is provided on which a computer program is stored. The computer program, when executed by a processor, causes the processor to perform the method according to the second aspect.

In a fifteenth aspect, a computer readable medium is provided having a computer program stored thereon. The computer program, when executed by a processor, causes the processor to perform the method according to the third aspect.

In a sixteenth aspect, a computer readable medium is provided on which a computer program is stored. The computer program, when executed by a processor, causes the processor to perform the method according to the fourth aspect.

It should be understood that the summary is not intended to identify key or essential features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The foregoing and other objects, features, and advantages of the disclosure will be more apparent from the following more particular description of some example embodiments of the disclosure, as illustrated in the accompanying drawings in which:

FIG. 1 illustrates an example communication network in which example embodiments of the present disclosure may be implemented;

fig. 2 is a flow chart of a communication method implemented at a first network device according to some embodiments of the present disclosure;

fig. 3 is a signaling diagram of an example process for selecting network devices for cooperative downlink transmission in accordance with some embodiments of the present disclosure;

Fig. 4 is a schematic diagram of an example transmission of downlink control information according to some embodiments of the present disclosure;

fig. 5 is a schematic diagram of an example transmission of downlink control information in accordance with some other embodiments of the present disclosure;

fig. 6 is a schematic diagram of an example transmission of downlink control information according to other embodiments of the present disclosure;

fig. 7 is a schematic diagram of an example transmission of downlink control information according to other embodiments of the present disclosure;

fig. 8 is a flow chart of a communication method implemented at a first network device according to some other embodiments of the present disclosure;

fig. 9 is a flow chart of a communication method implemented at a terminal device according to some other embodiments of the present disclosure;

fig. 10 is a flow chart of a communication method implemented at a second network device according to some other embodiments of the present disclosure; and

fig. 11 is a block diagram of an apparatus suitable for implementing example embodiments of the present disclosure.

The same or similar reference numbers will be used throughout the drawings to refer to the same or like elements.

Detailed Description

Principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and practicing the present disclosure without placing any limitation on the scope of the disclosure. The disclosure described herein may be implemented in various other ways besides those described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, the term "network device" refers to any suitable device on the network side of a communication network. The network devices may include any suitable devices in an access network of a communication network, including, for example, base Stations (BSs), TRPs, relays, access Points (APs), node BS (nodebs or NB), evolved nodebs (enodebs or enbs), gigabit nodebs (gNB), remote radio modules (RRUs), radio Headers (RH), remote Radio Heads (RRHs), low power nodes (such as femto, pico), etc.

The network devices may also include any suitable devices in the core network, including, for example, multi-standard radio (MSR) radio devices such as MSR BS, network controllers such as Radio Network Controllers (RNC) or Base Station Controllers (BSC), multi-cell/Multicast Coordination Entities (MCEs), mobile Switching Centers (MSC) and MMEs, operation and management (O & M) nodes, operation Support System (OSS) nodes, self-organizing network (SON) nodes, positioning nodes such as enhanced services mobile positioning centers (E-SMLC), and/or Mobile Data Terminals (MDT).

As used herein, the term "terminal device" refers to a device that is capable of, configured for, arranged for and/or operable for communicating with a network device or another terminal device in a communication network. The communication may involve the transmission and/or reception of wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information over the air. In some example embodiments, the terminal device may be configured to transmit and/or receive information without direct human interaction. For example, the terminal device may transmit information to the network device on a predetermined schedule when triggered by an internal or external event, or in response to a request from the network side.

Examples of terminal devices include, but are not limited to, user Equipment (UE), such as a smart phone, a wireless-enabled tablet computer, a laptop computer embedded device (LEE), a laptop computer installed device (LME), and/or a wireless Customer Premises Equipment (CPE). For purposes of discussion, some example embodiments will be described below with reference to a UE as an example of a terminal device, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of the present disclosure.

As used herein, the term "cell" refers to the area covered by radio signals transmitted by a network device. Terminal devices within a cell may be served by and access a communication network via network devices.

As used herein, the term "circuitry" may refer to one or more or all of the following: (a) Pure hardware circuit implementations (such as implementations in analog and/or digital circuitry only); and (b) a combination of hardware circuitry and software, such as (as applicable): (i) A combination of analog and/or digital hardware circuitry and software/firmware, and (ii) any portion of a hardware processor, software, and memory having software (including digital signal processors) that work in concert to cause a device, such as a mobile phone or server, to perform various functions; and (c) hardware circuitry and/or a processor, such as a microprocessor or a portion of a microprocessor, that requires software (e.g., firmware) to run but may not exist when operation is not required.

This definition of "circuitry" applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term "circuitry" also encompasses an implementation of a pure hardware circuit or processor (or processors) or a hardware circuit or processor and portions of its (or their) accompanying software and/or firmware. The term "circuitry" also encompasses, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

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. The term "include" and variations thereof are to be understood as open-ended terms, meaning "including, but not limited to. The term "based on" should be understood as "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". Other definitions (whether explicit or implicit) may be included below.

In release 15, downlink NCJT is discussed to support transmissions in both scenarios. One of the two scenarios is a multi-TRP downlink transmission with an ideal backhaul link, and the other scenario is a multi-TRP downlink transmission with a non-ideal backhaul link. To support different scenarios, some protocols are achieved regarding the principles of Physical Downlink Control Channel (PDCCH) transmission and Physical Downlink Shared Channel (PDSCH) transmission. For example, a single PDCCH transmission scheme for an ideal backhaul link is agreed upon. In a single PDCCH transmission scheme, a single PDSCH may be scheduled and separate layers are transmitted from separate TRPs. In addition, a multi-PDCCH transmission scheme for non-ideal backhaul is agreed. In the multi-PDCCH transmission scheme, each PDCCH schedules a corresponding PDSCH, and each PDSCH is transmitted from a separate TRP.

However, in release 15, it is not discussed how to determine a cluster of cooperative TRPs before cooperative PDCCH and PDSCH transmissions, especially for NR high-band systems requiring beam management. In addition, there is no discussion of how to guarantee robustness of single PDCCH transmission or multiple PDCCH transmission to increase transmission efficiency and decoding complexity.

To at least partially address the above and other potential problems, embodiments of the present disclosure provide a solution for determining a cluster of multiple network devices for cooperative downlink transmission. According to an embodiment of the present disclosure, a first network device serving a terminal device pre-selects one of a second network device and a third network device having a better uplink channel quality. The first network device instructs the pre-selected network device to initiate a measurement of the quality of the downlink channel to the terminal device. In turn, the first network device may decide whether to include the pre-selected network device in the cluster for cooperative downlink transmission based on the quality of the downlink channel.

With embodiments of the present disclosure, only pre-selected network devices need to initiate a measurement of the quality of the downlink channel to the terminal device. The terminal device only needs to measure the quality of the downlink channel in relation to the pre-selected network device. Thus, the processing complexity and the total processing time of the terminal device are reduced. The uplink overhead is reduced because the terminal device only needs to feed back the quality of the downlink channel related to the pre-selected network device.

Additionally, embodiments of the present disclosure provide a solution for cooperative downlink control channel transmission. According to an embodiment of the present disclosure, a serving network apparatus transmits a resource allocation indication for DCI associated with a cooperating network apparatus on a downlink data channel to a terminal apparatus. In this way, the decoding of DCI associated with the cooperative network device is independent of the decoding of DCI associated with the serving network device. Therefore, even if the decoding of DCI associated with the serving network device fails, the decoding of DCI associated with the cooperative network device is not affected by the failure. Thus, downlink data transmissions from the serving network device may be decoupled from downlink data transmissions from the cooperating network device.

Fig. 1 illustrates an example communication network 100 in which example embodiments of the present disclosure may be implemented. The network 100 includes a first network device 110, a second network device 120, a third network device 130, and a terminal device 140. It should be understood that the number of network devices and terminal devices is for illustration purposes only and is not meant to be limiting. Network 100 may include any suitable number of network devices and terminal devices suitable for implementing example embodiments of the present disclosure.

The communications in the network 100 may conform to any suitable standard including, but not limited to, global system for mobile communications (GSM), mobile internet of things extended coverage global system (EC-GSM-IoT), long Term Evolution (LTE), LTE evolution, LTE-advanced (LTE-a), wideband Code Division Multiple Access (WCDMA), code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), and the like. Further, the communication may be performed according to any generation of communication protocols currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols.

The terminal device 140 is served by the first network device 110. The second network device 120 and the third network device 130 may be configured as candidate network devices for cooperative downlink transmission to the terminal device 140. To improve the edge performance of the low frequency band or to provide high rank transmission (high rank transmission) for the high and low frequency bands, the first network device 110 may select one of the second and third network devices for cooperative downlink transmission.

Principles and implementations of the present disclosure will be described in detail below with reference to fig. 2, fig. 2 showing a flowchart of an example method 200 according to some embodiments of the present disclosure. For discussion purposes, the method 200 will be described with reference to fig. 1. The method 200 may relate to the first network device 110, the second network device 120, and the terminal device 140 in fig. 1. For example, the method 200 may be implemented at the first network device 110 shown in fig. 1. It should be understood that method 200 may include additional blocks not shown and/or may omit some of the blocks shown, and the scope of the present disclosure is not limited in this respect.

At block 210, the first network device 110 selects the second network device 120 for cooperative downlink transmission to the terminal device 140. In some embodiments, the first network device 110 may select the second network device 120 via a process 300 as shown in fig. 3.

Fig. 3 is a signaling diagram of an example process 300 for selecting network devices for cooperative downlink transmission in accordance with some embodiments of the present disclosure. The process 300 may involve the first network device 110, the second network device 120, the third network device 130, and the terminal device 140 as shown in fig. 1. It should be appreciated that process 300 may include other acts not shown and/or omit some acts shown. The scope of the present disclosure is not limited in this regard.

In some embodiments, upon event triggering, the first network device 110 may select one of the second network device 120 and the third network device 130 for cooperative downlink transmission. Examples of events may include, but are not limited to, the quality of the channel between the first network device 110 (and the terminal device) being below a threshold quality, and an increase in traffic to the terminal device 140.

In some embodiments, to select one of the second network device 120 and the third network device 130, the first network device 110 may send 3010 information about the configuration of the terminal device 140 to the second network device 120 and send 3020 information about the configuration of the terminal device 140 to the third network device 130. Examples of information about the configuration of the terminal device 140 include, but are not limited to, information about the configuration of the reference signal of the terminal device 140 and information about the beam of the terminal device 140.

Upon event triggering, the terminal device 140 sends 3030 a first uplink reference signal to the second network device 120 for measurement of a first quality of a first uplink channel between the second network device 120 and the terminal device 140. The terminal device 140 transmits 3040 a second uplink reference signal to the third network device 130 for measurement of a second quality of a second uplink channel between the third network device 130 and the terminal device 140.

Examples of the first uplink reference signal and the second uplink reference signal may include, but are not limited to, a Sounding Reference Signal (SRS). In some embodiments, the terminal device 140 may enable transmission of the first uplink reference signal and the second uplink reference signal in successive Orthogonal Frequency Division Multiplexing (OFDM) symbols (e.g., up to four OFDM symbols) by beam scanning mode transmission.

The second network device 120 measures a first quality of the first uplink channel by detecting a first uplink reference signal from the terminal device 140. The third network device 130 measures a second quality of the second uplink channel by detecting a second uplink reference signal from the terminal device 140. In some embodiments, each of the second network device 120 and the third network device 130 may perform a measurement of the quality of the respective uplink channel by performing a beam management procedure for uplink transmissions with the terminal device 140.

The second network device 120 sends 3050 an indication of the first quality and information about a pair of uplink beams associated with the first quality to the first network device 110. The third network device 130 sends 3060 an indication of the second quality and information about a pair of uplink beams associated with the second quality to the first network device 110.

The first network device 110 compares 3070 the first quality of the first uplink channel with the second quality of the second uplink channel.

If the first quality is higher than the second quality, the first network device 110 sends an indication to the second network device 120 of: a measurement of a third quality of the downlink channel between the second network device 120 and the terminal device 140 is initiated. If the second quality is higher than the first quality, the first network device 110 sends an indication to the third network device 130 of: a measurement of a fourth quality of the downlink channel between the third network device 130 and the terminal device 140 is initiated. In this example process, it is assumed that the first quality is higher than the second quality. Thus, the first network device 110 sends 3080 to the second network device 120 an indication to initiate measurement of the third quality of the downlink channel.

In case the first quality is higher than the second quality, the first network device 110 sends 3090 information about a pair of uplink beams associated with the first quality to the terminal device 140. In some embodiments, the pair of uplink beams associated with the first quality may include an uplink transmission beam on the terminal device 140 side and an uplink reception beam on the second network device 120 side. The terminal device 140 transmits the first uplink reference signal using the uplink transmission beam. The second network device 120 measures a first quality of the first uplink channel by receiving the first uplink reference signal using the uplink receive beam. In some embodiments, with the beam correspondence attribute, the uplink receive beam on the second network device 120 side will be used as the transmit beam for the downlink transmission from the second network device 120.

Upon receiving the indication to initiate the measurement of the third quality of the downlink channel, the second network device 120 sends 3100 a downlink reference signal for the measurement to the terminal device 140.

The terminal device 140 performs a measurement of the third quality of the downlink channel by detecting a downlink reference signal from the second network device 120. In some embodiments, the terminal device 140 may perform the measurement of the third quality of the downlink by performing a beam management procedure for downlink transmissions with the second network device 120.

The terminal device 140 sends 3110 an indication of the third quality to the first network device 110 for a decision of the cooperative downlink transmission from the first network device 110 and the second network device 120 to the terminal device 140.

Upon receiving the indication of the third quality of the downlink channel between the second network device 120 and the terminal device 140, the first network device 110 compares 3120 the third quality with the first threshold quality. In some embodiments, the first network device 110 may use the quality of the downlink channel between the first network device 110 and the terminal device 140 as a threshold quality. In other embodiments, the first threshold quality may be a predefined quality.

If it is determined that the third quality exceeds the first threshold quality, the first network device 110 sends 3130 to the second network device 120 an indication that the second network device 120 is selected for cooperative downlink transmission to the terminal device 140.

It should be appreciated that the process 300 for selecting network devices for cooperative downlink transmission is described by way of example. In some embodiments, the first network device 110 may employ any known procedure to select a cooperating network device. The scope of the present disclosure is not limited in this regard. For example, the terminal device 140 may perform a beam management procedure with the second network device 120 to determine the quality of the uplink channel, the quality of a pair of uplink beams, and the downlink channel. The terminal device 140 may then perform a beam management procedure with the third network device 130 to measure the quality of the uplink channel, the quality of the pair of uplink beams and the downlink channel. The terminal device 140 then feeds back to the first network device 110 the quality of the downlink channel associated with the second network device 120 and the quality of the downlink channel associated with the third network device 130. Thus, the first network device 110 compares the two qualities to a threshold to select one of the second network device and the third network device for cooperative downlink transmission.

With the process 300 for selecting a cooperating network device, the first network device 110 pre-selects (at 3070) one of the second and third network devices having a better uplink channel quality. Thus, only the pre-selected network device (e.g., the second network device 120) needs to initiate a measurement of the quality of the downlink channel to the terminal device 140. The terminal device 140 need only measure (at 3100) the quality of the downlink channel associated with the pre-selected network device. Thus, the processing complexity and the total processing duration of the terminal device 140 are reduced. Because the terminal device 140 only needs to feedback (at 3110) the quality of the downlink channel associated with the pre-selected network device, the uplink overhead is reduced.

Referring again to fig. 2, after selecting the second network device 120 for cooperative downlink transmission, at 220, the first network device 110 sends a resource allocation indication for DCI associated with the second network device 120, along with information regarding decoding of the DCI, to the terminal device 140 on a downlink data channel. For discussion purposes, the DCI associated with the second network device 120 is referred to as a second DCI or dci#2. Similarly, the DCI associated with the first network device 110 is referred to as a first DCI or dci#1.

In some embodiments, the first network device 110 may transmit the resource allocation indication for the second DCI and the information regarding decoding of the second DCI via Radio Resource Control (RRC) signaling or a Medium Access Control (MAC) Control Element (CE).

According to the present disclosure, since the resource allocation indication of the second DCI is transmitted on the downlink data channel instead of the downlink control channel, decoding of the second DCI is independent of decoding of the first DCI. Therefore, even if the decoding of the first DCI fails, the decoding of the second DCI is not affected by the failure. Thus, the downlink data transmission from the first network device 110 may be decoupled from the downlink data transmission from the second network device 120. In addition, since the decoding of the second DCI is independent of the decoding of the first DCI, the decoding of the first DCI and the second DCI has no time delay. Thus, decoding of downlink data transmissions from the first network device 110 and from the second network device 120 is expedited.

At block 230, the first network device 110 determines whether the link between the first network device 110 and the second network device 120 is an ideal backhaul link.

If it is determined that the link is an ideal backhaul link, at 240, the first network device 110 transmits DCI to the terminal device 140 on at least a first downlink control channel between the first network device 110 and the terminal device 140.

Hereinafter, transmission of the first DCI and the second DCI in the case of an ideal backhaul link will be described with reference to fig. 4 and 5.

Fig. 4 is a schematic diagram of an example DCI transmission according to some embodiments of the present disclosure. As shown, subframe 400 includes a control region 410, a data region 420, and an Uplink (UL) region 430.

The data region 420 is configured to carry downlink data. UL zone 430 is configured to carry UL feedback from terminal device 140.

The control region 410 is configured to carry downlink control information. The control region 410 includes a sub-region 411 and a sub-region 412. In some embodiments, sub-region 412 follows sub-region 411.

The sub-region 411 is predefined for transmission of dci#1 associated with the first network device 110. The sub-region 412 is predefined for transmission of dci#2 associated with the second network device 120.

The sizes of sub-regions 411 and 412 may be preconfigured. In some embodiments, the size of the sub-region 411 may be preconfigured as two or three Orthogonal Frequency Division Multiplexing (OFDM) symbols. The first network device 110 may determine whether to employ two OFDM symbols or three OFDM symbols based on a comparison of the channel quality between the first network device 110 and the terminal device 140 to a second threshold quality. In other words, the starting position of the sub-region 410 in the sub-frame 410 may be determined based on a comparison of the channel quality to a second threshold quality.

For example, if it is determined that the quality of the channel exceeds the second threshold quality, the first network device 110 may determine to use two OFDM symbols for transmission of dci#1. Thus, the third OFDM symbol in subframe 410 is determined as the starting position of sub-region 412. On the other hand, if it is determined that the channel quality is lower than the second threshold quality, the first network device 110 may determine to use three OFDM symbols for transmission of dci#1. Thus, the fourth symbol in subframe 410 is determined as the starting position of sub-region 412.

In some embodiments, the size of the sub-region 412 may be preconfigured based on the number of terminal devices supported by the first network device 110 for concurrent cooperative downlink transmissions. For example, if the number of terminal devices is equal to one or two, the size of the sub-region 412 may be preconfigured to one OFDM symbol. If the number of terminal devices is greater than two, the size of the sub-region 412 may be preconfigured to more OFDM symbols.

In some embodiments, the resource allocation indication for dci#2 may indicate the starting position of sub-region 412.

In some embodiments, the first network device 110 and the second network device 120 may perform joint transmission of dci#1 and dci#2 encoded with a predetermined space-time block code (STBC), as will be described with reference to fig. 5.

Fig. 5 is a schematic diagram of an example transmission of encoded DCI according to some other embodiments of the present disclosure. As shown, the first network device 110 encodes dci#1 and dci#2 using a predetermined STBC to obtain first encoded DCI and second encoded DCI. Dci#1 may be denoted by S1, and the first encoded DCI may be the same as dci#1 and denoted by S1. Dci#2 may be represented by S2, and the second encoded DCI may be an inverse of the conjugate transpose of S2 and represented by-S2 x, where x represents the conjugate transpose. The first network device 110 transmits a first coded DCI (i.e. -S1) in the sub-region 411 and a second coded DCI (i.e. -S2) in the sub-region 412.

The subframe 500 for the second network device 120 includes a control region 510, a data region 520, and a UL region 530. The data region 520 is configured to carry downlink data. UL zone 530 is configured to carry UL feedback from terminal device 140. The control region 510 is configured to carry downlink control information. The control region 510 includes a sub-region 511 and a sub-region 512. In some embodiments, sub-region 512 follows sub-region 511.

The second network device 120 encodes dci#1 and dci#2 using a predetermined STBC to obtain third encoded DCI and fourth encoded DCI. Dci#1 may be represented by S1, and the third encoded DCI may be a conjugate transpose of dci#1 and represented by S1, where x represents the conjugate transpose. Dci#2 may be denoted by S2, and fourth coded DCI may be identical to dci#2 and denoted by S2. While the first network device 110 transmits S1 in sub-region 411 and-S2 in sub-region 412, the second network device 120 transmits the third coded DCI (i.e., S2) in sub-region 511 and the fourth coded DCI (i.e., S1) in sub-region 512.

Upon receiving the first encoded DCI, the second encoded DCI, the third encoded DCI, and the fourth encoded DCI, the terminal device 140 decodes them to obtain dci#1 and dci#2. By joint transmission of dci#1 and dci#2 encoded with a predetermined STBC, decoding performance of dci#1 and dci#2 is improved.

It should be understood that the joint transmission procedure of dci#1 and dci#2 encoded using STBC is applicable to both low-band transmission and high-low band transmission. In the case of high-low band transmission, a wideband beam will be used for dci#1 and dci#2 from each of the first and second network devices, and a narrowband beam will be used for downlink data from each of the first and second network devices. Not only beamforming gain but also STBC coding gain may be achieved. This may provide a more robust DCI transmission to ensure more successful multi-PDSCH decoding with lower complexity at the terminal device 140 side.

Referring again to fig. 2, if it is determined at block 230 that the link is a non-ideal backhaul link, at 250 the first network device 110 sends a first indication to the terminal device 140 in a first subframe that a downlink transmission from the second network device 120 is to be initiated.

In some embodiments, the first network device 110 may send the first indication in a control region in the first subframe. Alternatively, if the control region is too congested and does not have sufficient resources for transmitting the first indication, the first network device 110 may transmit the first indication in a data region in the first subframe to ensure decoding performance for the first indication.

Hereinafter, an example transmission of the first indication in the control region will be described with reference to fig. 6 and 7.

Fig. 6 is a schematic diagram of an example transmission of a first indication according to some embodiments of the present disclosure. In the example shown in fig. 6, the first network device 110 sends a first indication in a control region in a first subframe that a downlink transmission from the second network device 120 is to be initiated. The terminal device 140 sends a positive acknowledgement to the first network device 110 and the second network device 120 indicating that the downlink transmission is acceptable. Upon receiving the positive acknowledgement, the first network device 110 disables transmission of the first indication in the control region of the second subframe subsequent to the first subframe.

As shown, the set of subframes 600 for the first network device 110 includes: a subframe 610 and a subframe 620 subsequent to the subframe 610.

The subframe 610 includes a control region 611, a data region 612, and a UL region 613. The subframe 620 includes a control region 621, a data region 622, and a UL region 623. The control regions 611 and 621 are configured to carry DCI associated with the first network device 110. The data areas 612 and 622 are configured to carry downlink data from the first network device 110. UL regions 613 and 623 are configured to carry UL feedback from terminal device 140.

Similarly, the set of subframes 605 for the second network device 120 includes: a subframe 630 and a subframe 640 after the subframe 630.

The subframe 630 includes a control region 631, a data region 632, and a UL region 633. The subframe 640 includes a control region 641, a data region 642, and a UL region 643. The control regions 631 and 630 641 are configured to carry DCI associated with the first network device 110. The data regions 632 and 642 are configured to carry downlink data from the second network device 120. UL regions 633 and 643 are configured to carry UL feedback from terminal device 140.

As shown in fig. 6, the first network device 110 sends a first indication 6111 in the control region 611 of the subframe 610 that the downlink transmission from the second network device 120 is to be initiated.

Upon receiving the first indication 6111, the terminal device 140 decodes the first indication 6111. If the decoding of the first indication 6111 is successful, the terminal device 140 may determine whether the downlink transmission from the second network device 120 is acceptable. If the downlink transmission is determined to be acceptable, the terminal device 140 sends a positive acknowledgement to the first network device 110 indicating that the downlink transmission is acceptable. In the example shown in fig. 6, the terminal device 140 sends a positive acknowledgement to the first network device 110 in UL zone 613, and the positive acknowledgement is denoted as "a".

In addition, if it is determined that the downlink transmission is acceptable, the terminal device 140 also transmits a positive acknowledgement to the second network device 120 indicating that the downlink transmission is acceptable. In the example shown in fig. 6, the terminal device 140 sends a positive acknowledgement to the second network device 120 in UL zone 633.

Upon receiving the positive acknowledgement, the second network device 120 includes dci#2 into the control region 641 of subframe 640 and downlink data into the data region 642 in order to initiate downlink transmission to the terminal device 140.

Further, if the first network device 110 receives a positive acknowledgement, the first network device 110 disables transmission of the first indication 6111 in the control region 621 of the subframe 620 following the subframe 610.

In some embodiments, if the same type of traffic and different data layers of traffic are to be transmitted from the first network device 110 and the second network device 120, the first network device 110 may transmit in the control region 611 of the subframe 610: an indication 6112 of the order of decoding of the data channels associated with the first network device 110 and the data channels associated with the second network device 120. For example, the indication 6112 may indicate that the data channel associated with the first network device 110 is to be decoded first to increase the accuracy of the decoding of the data channel.

Fig. 7 is a schematic diagram of an example transmission of a first indication according to some other embodiments of the present disclosure. In the example shown in fig. 7, the first network device 110 sends a first indication in a control region in a first subframe that a downlink transmission from the second network device 120 is to be initiated. The terminal device 140 sends a negative acknowledgement to the first network device 110 and the second network device 120 indicating that the downlink transmission is denied. Upon receiving the negative acknowledgement, the first network device 110 sends a first indication in a control region of a third subframe subsequent to the first subframe.

As shown, the set of subframes 700 for the first network device 110 includes a subframe 710 and a subframe 720 following the subframe 710.

The subframe 710 includes a control region 711, a data region 712, and a UL region 713. Subframe 720 includes a control region 721, a data region 722, and a UL region 723. The control regions 711 and 721 are configured to carry DCI associated with the first network device 110. The data areas 712 and 722 are configured to carry downlink data from the first network device 110. UL regions 713 and 723 are configured to carry UL feedback from terminal device 140.

Similarly, the set of subframes 705 of the second network device 120 includes a subframe 730 and a subframe 740 following the subframe 730.

The subframe 730 includes a control region 731, a data region 732, and a UL region 733. Subframe 740 includes a control region 741, a data region 742, and a UL region 743. Control regions 731 and 741 are configured to carry DCI associated with first network device 110. The data regions 732 and 742 are configured to carry downlink data from the second network device 120. UL regions 733 and 743 are configured to carry UL feedback from terminal device 140.

Similar to the example shown in fig. 6, in the example shown in fig. 7, the first network device 110 sends a first indication 6111 in the control region 711 of the subframe 710 that the downlink transmission from the second network device 120 is to be initiated.

Upon receiving the first indication 6111, the terminal device 140 decodes the first indication 6111. If the decoding of the first indication 6111 is successful, the terminal device 140 may determine whether the downlink transmission from the second network device 120 is acceptable. In some embodiments, the terminal device 140 may determine whether to accept or reject the downlink transmission based on the capabilities of the terminal device 140. In other words, the terminal device 140 may control the reception of a cooperative transmission from the first network device and the second network device or the reception of a single transmission from the first network device.

If it is determined that the downlink transmission from the second network device 120 is not acceptable, the terminal device 140 sends a negative acknowledgement to the first network device 110 indicating that the downlink transmission is denied. In the example shown in fig. 7, the terminal device 140 sends a negative acknowledgement to the first network device 110 in the UL region 713, and the negative acknowledgement is denoted as "N".

In addition, if it is determined that the downlink transmission is not acceptable, the terminal device 140 also sends a negative acknowledgement to the second network device 120 indicating that the downlink transmission is denied. In the example shown in fig. 7, the terminal device 140 sends a negative acknowledgement to the second network device 120 in the UL region 733.

Upon receiving the negative acknowledgement, the second network device 120 does not include dci#2 into the control region 741 of the subframe 740 or include downlink data into the data region 742. In this case, the terminal device 140 will not perform blind decoding of dci#2. Accordingly, power consumption of the terminal device 140 can be saved, and processing complexity of the terminal device 140 can be reduced.

Further, if the first network device 110 receives a negative acknowledgement, the first network device 110 sends a first indication 6111 in the control region 721 of the subframe 720 after the subframe 710.

Accordingly, upon receiving the first indication 6111 in the control region 721, the terminal device 140 may send a positive or negative acknowledgement (a/N) to the first network device 110 in the UL region 723 and to the second network device 120 in the UL region 743.

Fig. 8 is a flow chart of a communication method 800 according to some other embodiments of the present disclosure. For discussion purposes, the method 800 will be described with reference to fig. 1. The method 800 may involve the first network device 110, the second network device 120, and the terminal device 140 of fig. 1. For example, the method 800 may be implemented at the first network device 110 shown in fig. 1. It should be understood that method 800 may include additional blocks not shown and/or that some blocks shown may be omitted, and the scope of the disclosure is not limited in this respect.

At block 810, the first network device 110 compares a first quality of a first uplink channel with a second quality of a second uplink channel. The first uplink channel is between the second network device 120 and the terminal device 140 served by the first network device 110, and the second uplink channel is between the third network device 130 and the terminal device 140.

At block 820, in response to the first quality being higher than the second quality, the first network device 110 sends an indication to the second network device 120 of: a measurement of a third quality of the downlink channel between the second network device 120 and the terminal device 140 is initiated.

At block 830, the first network device 110 sends information regarding a pair of uplink beams associated with the first quality to the terminal device 140.

At block 840, the first network device 110 receives an indication of a third quality from the terminal device 140.

At block 850, in response to the third quality exceeding the first threshold quality, the first network device 110 sends an indication 140 to the second network device 120 that the second network device 120 is selected for cooperative downlink transmission to the terminal device.

Fig. 9 is a flow chart of a communication method 900 according to some other embodiments of the present disclosure. For discussion purposes, the method 900 will be described with reference to FIG. 1. The method 900 may involve the first network device 110, the second network device 120, and the terminal device 140 of fig. 1. The method 900 may be implemented at the terminal device 140 as shown in fig. 1. It should be understood that method 900 may include additional blocks not shown and/or may omit some of the blocks shown, and the scope of the present disclosure is not limited in this respect.

At block 910, the terminal device 140 receives, on a downlink data channel between the first network device 110 and the terminal device 140, a resource allocation indication for downlink control information, DCI, associated with the second network device 120 and information regarding decoding of the DCI.

At block 920, in response to determining that the resource allocation indication indicates resources on a first downlink control channel between the first network device 110 and the terminal device 140, the terminal device 140 receives DCI on the first downlink control channel.

In some example embodiments, the method 900 further comprises: the quality of the channel between the first network device and the terminal device is transmitted to the first network device for determining a starting position of the second sub-region in the subframe.

In some example embodiments, receiving other DCIs and DCIs includes: receiving first coded DCI and second coded DCI; and decoding the first coded DCI and the second coded DCI by utilizing a preset space-time block code to acquire other DCIs and DCIs.

In some example embodiments, the method 900 further comprises: in response to determining that the resource allocation indication indicates resources on a second downlink control channel between the second network device and the terminal device, a first indication is received in a first subframe from the first network device that a downlink transmission from the second network device is to be initiated.

In some example embodiments, the method 900 further comprises: determining, in response to decoding the first indication being successful, whether the downlink transmission is acceptable; in response to determining that the downlink transmission is acceptable, sending a positive acknowledgement to the first network device indicating that the downlink transmission is acceptable; and in response to determining that the downlink transmission is unacceptable, sending a negative acknowledgement to the first network device indicating that the downlink transmission is denied.

In some example embodiments, the method 900 further comprises: the first indication is received in a third subframe subsequent to the first subframe in response to sending a negative acknowledgement indicating that the downlink transmission was denied.

In some example embodiments, the method 900 further comprises: transmitting a first uplink reference signal to the second network device for measurement of a first quality of a first uplink channel between the second network device and the terminal device; transmitting a second uplink reference signal to the third network device for measurement of a second quality of a second uplink channel between the third network device and the terminal device; in response to receiving information from the first network device regarding a pair of uplink beams associated with the first quality, performing a measurement of a third quality of a downlink channel between the second network device and the terminal device; and sending an indication of the third quality to the first network device for use in deciding on a cooperative downlink transmission from the first network device and the second network device to the terminal device.

Fig. 10 is a flow chart of a communication method 1000 according to some other embodiments of the present disclosure. For discussion purposes, the method 1000 will be described with reference to FIG. 1. Method 1000 may involve first network device 110, second network device 120, and terminal device 140 in fig. 1. The method 1000 may be implemented at the second network device 120 shown in fig. 1. It should be understood that method 1000 may include additional blocks not shown and/or that some blocks shown may be omitted, and the scope of the disclosure is not limited in this respect.

At block 1010, the second network device 120 measures a first quality of a first uplink channel between the second network device 120 and the terminal device 140 served by the first network device 110.

At block 1020, the second network device 120 sends an indication of the first quality and information regarding a pair of uplink beams associated with the first quality to the first network device 110.

At block 1030, in response to receiving an indication from the first network device 110 to initiate a measurement of a quality of a downlink channel between the second network device 120 and the terminal device 140, the second network device 120 sends a downlink reference signal for the measurement to the terminal device 140.

At block 1040, the second network device 120 receives an indication from the first network device 110 that the second network device 120 is selected for cooperative downlink transmission to the terminal device 140 in response to the quality of the downlink channel exceeding the first threshold quality.

In some example embodiments, the method 1000 further comprises: in response to receiving a positive acknowledgement from the terminal device 140 indicating that the downlink transmission from the second network device 120 is accepted, the downlink transmission is initiated.

In some embodiments, an apparatus (e.g., first network device 110) capable of performing method 200 may include means for performing the respective steps of method 200. The modules may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules.

In some embodiments, the apparatus comprises: means for selecting, at a first network device serving the terminal device, a second network device for cooperative downlink transmission to the terminal device; means for transmitting, to the terminal device, a resource allocation indication of downlink control information, DCI, associated with the second network device and information regarding decoding of the DCI on a downlink data channel; means for determining whether a link between the first network device and the second network device is an ideal backhaul or a non-ideal backhaul; and means for transmitting DCI to the terminal device on at least a first downlink control channel between the first network device and the terminal device in response to determining that the link is an ideal backhaul link.

In some embodiments, the means for selecting a second network device for cooperative downlink transmission to the terminal device comprises: means for comparing a first quality of a first uplink channel between a second network device and a terminal device with a second quality of a second uplink channel between a third network device and the terminal device; means for sending, to the second network device, in response to the first quality being higher than the second quality, an indication of: initiating a measurement of a third quality of a downlink channel between the second network device and the terminal device; means for transmitting information about a pair of uplink beams associated with a first quality to a terminal device; means for receiving an indication of a third quality from the terminal device; and means for sending, to the second network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to determining that the third quality exceeds the first threshold quality.

In some embodiments, the means for transmitting DCI comprises: means for transmitting DCI in a predefined control region in a subframe.

In some embodiments, the means for transmitting DCI in a predefined control region comprises: means for transmitting other DCI associated with the first network device in a first sub-region of the predefined control region and transmitting the DCI in a second sub-region of the predefined control region, the second sub-region being subsequent to the first sub-region.

In some embodiments, the size of the predefined control region is preconfigured.

In some embodiments, the apparatus further comprises: means for obtaining from the terminal device a quality of a channel between the first network device and the terminal device; means for comparing the quality of the channel with a second threshold quality; and means for determining a starting position of the second sub-region in the sub-frame based on the comparison.

In some embodiments, the means for determining a starting position of the second sub-region in the sub-frame comprises: means for determining a third symbol in the subframe as a starting position of the second sub-region in response to the quality of the channel exceeding a second threshold quality; and means for determining a fourth symbol in the subframe as a starting position of the second sub-region in response to the quality of the channel being below a second threshold quality.

In some embodiments, the means for sending the resource allocation indication comprises: means for transmitting a resource allocation indication indicating a starting position of the second sub-region.

In some embodiments, the means for transmitting other DCI and DCI comprises: means for encoding other DCI and DCI with a predetermined space-time block code to obtain first encoded DCI and second encoded DCI; and means for transmitting the first encoded DCI and the second encoded DCI.

In some embodiments, the apparatus further comprises: means for transmitting a first indication to the terminal device in a first subframe that a downlink transmission from the second network device is to be initiated in response to determining that the link is a non-ideal backhaul link.

In some embodiments, the means for transmitting the first indication comprises: the apparatus includes means for transmitting a first indication in a control region of a first subframe.

In some embodiments, the means for transmitting the first indication comprises: the apparatus includes means for transmitting a first indication in a data region of a first subframe.

In some embodiments, the apparatus further comprises: means for disabling transmission of the first indication in a second subframe subsequent to the first subframe in response to receiving a positive acknowledgement indicating that the downlink transmission from the second network device is accepted.

In some embodiments, the apparatus further comprises: means for transmitting the first indication in a third subframe subsequent to the first subframe in response to receiving a negative acknowledgement indicating that the downlink transmission from the second network device is denied.

In some embodiments, an apparatus (e.g., first network device 110) capable of performing method 800 may include means for performing the respective steps of method 800. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules.

In some embodiments, the apparatus comprises: means for comparing a first quality of a first uplink channel between a second network device and a terminal device served by the first network device with a second quality of a second uplink channel between a third network device and the terminal device; means for sending, in response to the first quality being higher than the second quality, to the second network device an indication of: initiating a measurement of a third quality of a downlink channel between the second network device and the terminal device; means for transmitting information about a pair of uplink beams associated with a first quality to a terminal device; means for receiving an indication of a third quality from the terminal device; and means for sending, to the second network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to determining that the third quality exceeds the first threshold quality.

In some embodiments, an apparatus (e.g., terminal device 140) capable of performing method 900 may include means for performing the respective steps of method 900. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules.

In some embodiments, the apparatus comprises: means for receiving, on a downlink data channel between a first network device and a terminal device, a resource allocation indication for downlink control information, DCI, associated with a second network device and information regarding decoding of the DCI; and means for receiving DCI on a first downlink control channel in response to determining that the resource allocation indication indicates resources on the first downlink control channel between the first network device and the terminal device.

In some embodiments, the means for receiving DCI comprises: means for receiving DCI in a predefined control region in a subframe.

In some embodiments, the means for receiving DCI in a predefined control region comprises: means for receiving other DCI associated with the first network device in a first sub-region of the predefined control region and receiving the DCI in a second sub-region of the predefined control region, the second sub-region being subsequent to the first sub-region.

In some embodiments, the apparatus further comprises: means for transmitting to the first network device a quality of a channel between the first network device and the terminal device for determining a starting position of the second sub-region in the subframe.

In some embodiments, the means for receiving the resource allocation indication comprises: means for receiving a resource allocation indication indicating a starting position of the second sub-region.

In some embodiments, the starting position of the second sub-region is a third symbol in the subframe.

In some embodiments, the starting position of the second sub-region is a fourth symbol in the subframe.

In some embodiments, the means for receiving additional DCI and DCI comprises: means for receiving a first encoded DCI and a second encoded DCI; and means for decoding the first encoded DCI and the second encoded DCI with a predetermined space-time block code to obtain other DCIs and DCIs.

In some embodiments, the apparatus further comprises: means for receiving, in response to determining that the resource allocation indication indicates resources on a second downlink control channel between the second network device and the terminal device, a first indication from the first network device that a downlink transmission from the second network device is to be initiated in a first subframe.

In some embodiments, the means for receiving the first indication comprises: the apparatus includes means for receiving a first indication in a control region of a first subframe.

In some embodiments, the means for receiving the first indication comprises: the apparatus includes means for receiving a first indication in a data region of a first subframe.

In some embodiments, the apparatus further comprises: means for determining whether the downlink transmission is acceptable in response to the decoding of the first indication being successful; means for transmitting a positive acknowledgement to the first network device indicating that the downlink transmission is acceptable in response to determining that the downlink transmission is acceptable; and means for transmitting a negative acknowledgement to the first network device indicating that the downlink transmission was denied in response to determining that the downlink transmission was not acceptable.

In some embodiments, the apparatus further comprises: means for receiving a first indication in a third subframe subsequent to the first subframe in response to transmitting a negative acknowledgement indicating that downlink transmission was denied.

In some embodiments, an apparatus (e.g., second network device 120) capable of performing method 800 may include means for performing the respective steps of method 1000. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules.

In some embodiments, the apparatus comprises: means for measuring, at the second network device, a first quality of a first uplink channel between the second network device and a terminal device served by the first network device; means for transmitting an indication of a first quality and information about a pair of uplink beams associated with the first quality to a first network device; means for transmitting a downlink reference signal for measurement to the terminal device in response to receiving an indication from the first network device to initiate measurement of quality of a downlink channel between the second network device and the terminal device; and means for receiving, from the first network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to the quality of the downlink channel exceeding a first threshold quality.

In some embodiments, the apparatus further comprises: means for initiating a downlink transmission in response to receiving a positive acknowledgement from the terminal device indicating that the downlink transmission from the second network device is accepted.

Fig. 11 is a simplified block diagram of a device 1100 suitable for implementing embodiments of the present disclosure. Device 1100 may be considered another example implementation of network devices 110 and 120 and terminal device 140 as shown in fig. 1. Thus, device 1100 may be implemented at network device 110 or 120 or terminal device 140, or as at least a portion of network device 110 or 120 or terminal device 140.

As shown, device 1100 includes a processor 1110, a memory 1120 coupled to processor 1110, suitable Transmitters (TX) and Receivers (RX) 1140 coupled to processor 1110, and a communication interface coupled to TX/RX 1140. Memory 1120 stores at least a portion of program 1130. TX/RX 1140 is used for two-way communication. TX/RX 1140 has at least one antenna to facilitate communications, although in practice, the access nodes referred to in this application may have several antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 interface for bi-directional communication between enbs, an S1 interface for communication between a Mobility Management Entity (MME)/serving gateway (S-GW) and an eNB, a Un interface for communication between an eNB and a Relay Node (RN), or a Uu interface for communication between an eNB and a UE.

Program 1130 is assumed to include program instructions that, when executed by an associated processor 1110, enable device 1100 to operate in accordance with embodiments of the present disclosure, as discussed herein with reference to fig. 1-10. The embodiments herein may be implemented by computer software executable by the processor 1110 of the device 1100, or by hardware, or by a combination of software and hardware. The processor 1110 may be configured to implement various embodiments of the present disclosure. Further, a combination of processor 1110 and memory 1120 may form a processing device 1150 suitable for implementing various embodiments of the present disclosure.

Memory 1120 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as non-transitory computer readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory, as non-limiting examples. Although only one memory 1120 is shown in device 1100, there may be several physically distinct memory modules in device 1100. The processor 1110 may be of any type suitable for a local technology network and may include, as non-limiting examples, one or more of the following: general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs), and processors based on a multi-core processor architecture. The device 1100 may have multiple processors, such as an application-specific integrated circuit chip that is slaved in time to a clock that is synchronized to the master processor.

In general, the various physical embodiments of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. 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. While various aspects of the example embodiments of the present disclosure are 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.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product comprises computer executable instructions, such as those included in program modules, that are executed in a device on a target real or virtual processor to perform the methods 800, 900 and 1000 as described above with reference to fig. 2, 8, 9 and 10. Generally, program modules include routines, programs, libraries, objects, classes, components, data types, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within local or distributed devices. In distributed devices, program modules may be located in both local and remote memory storage media.

Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of the carrier include a signal, a computer-readable medium.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus or devices, or any suitable combination thereof. More specific examples of a computer-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

Moreover, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Also, while the above discussion contains several specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method for communication, comprising:

selecting, at a first network device serving a terminal device, a second network device for cooperative downlink transmission to the terminal device;

transmitting, to the terminal device on a downlink data channel, a resource allocation indication for downlink control information, DCI, associated with the second network device and information regarding decoding of the DCI;

determining whether a link between the first network device and the second network device is an ideal backhaul link or a non-ideal backhaul link; and

i) Transmitting the DCI to the terminal device on at least a first downlink control channel between the first network device and the terminal device in response to determining that the link is the ideal backhaul link, or ii) transmitting a first indication to the terminal device in a first subframe that a downlink transmission from the second network device is to be initiated in response to determining that the link is the non-ideal backhaul link.

2. The method of claim 1, wherein selecting the second network device for the cooperative downlink transmission to the terminal device comprises:

comparing a first quality of a first uplink channel between the second network device and the terminal device with a second quality of a second uplink channel between a third network device and the terminal device;

in response to the first quality being higher than the second quality, sending an indication to the second network device of: initiate a measurement of a third quality of a downlink channel between the second network device and the terminal device;

transmitting information about a pair of uplink beams associated with the first quality to the terminal device;

receiving an indication of the third quality from the terminal device; and

in response to determining that the third quality exceeds a first threshold quality, an indication is sent to the second network device that the second network device is selected for cooperative downlink transmission to the terminal device.

3. The method of claim 1, wherein transmitting the DCI comprises:

The DCI is transmitted in a predefined control region in a subframe.

4. The method of claim 3, wherein transmitting the DCI in the predefined control region comprises:

other DCI associated with the first network device is transmitted in a first sub-region of the predefined control region, and the DCI is transmitted in a second sub-region of the predefined control region, the second sub-region being subsequent to the first sub-region.

5. The method of claim 4, wherein the size of the predefined control region is preconfigured.

6. The method of claim 4, further comprising:

acquiring the quality of a channel between the first network device and the terminal device from the terminal device;

comparing the quality of the channel to a second threshold quality; and

a starting position of the second sub-region in the sub-frame is determined based on the comparison.

7. The method of claim 6, wherein determining the starting position of the second sub-region in the subframe comprises:

determining a third symbol in the subframe as the starting position of the second sub-region in response to the quality of the channel exceeding the second threshold quality; and

In response to the quality of the channel being below the second threshold quality, a fourth symbol in the subframe is determined to be the starting position of the second sub-region.

8. The method of claim 6, wherein transmitting the resource allocation indication comprises:

-transmitting the resource allocation indication indicating the starting position of the second sub-region.

9. The method of claim 4, wherein transmitting the other DCI and the DCI comprises:

encoding the other DCI and the DCI by utilizing a preset space-time block code to obtain first encoded DCI and second encoded DCI; and

and transmitting the first coded DCI and the second coded DCI.

10. The method of claim 1, wherein sending the first indication comprises:

the first indication is sent in a control region in the first subframe.

11. The method of claim 1, wherein sending the first indication comprises:

the first indication is sent in a data region in the first subframe.

12. The method of claim 1, further comprising:

in response to receiving a positive acknowledgement indicating that the downlink transmission from the second network device was accepted, disabling transmission of the first indication in a second subframe subsequent to the first subframe.

13. The method of claim 1, further comprising:

the first indication is sent in a third subframe subsequent to the first subframe in response to receiving a negative acknowledgement indicating that the downlink transmission from the second network device was denied.

14. A method of communication, comprising:

comparing a first quality of a first uplink channel between a second network device and a terminal device served by the first network device with a second quality of a second uplink channel between a third network device and the terminal device;

receiving an indication of the third quality from the terminal device; and

15. A method of communication, comprising:

receiving, on a downlink data channel between a first network device and a terminal device, a resource allocation indication for downlink control information, DCI, and information regarding decoding of the DCI, the DCI being associated with a second network device; and

i) Receiving the DCI on a first downlink control channel between the first network device and the terminal device in response to determining that the resource allocation indication indicates resources on the first downlink control channel, or ii) receiving a first indication from the first network device that a downlink transmission from the second network device is to be initiated in a first subframe in response to determining that the resource allocation indication indicates resources on a second downlink control channel between the second network device and the terminal device.

16. The method of claim 15, wherein receiving the DCI comprises:

the DCI is received in a predefined control region in a subframe.

17. The method of claim 16, wherein receiving the DCI in the predefined control region comprises:

receiving other DCI associated with the first network device in a first sub-region of the predefined control region, and receiving the DCI in a second sub-region of the predefined control region, the second sub-region being subsequent to the first sub-region.

18. The method of claim 17, wherein the size of the predefined control region is preconfigured.

19. The method of claim 17, further comprising:

the quality of the channel between the first network device and the terminal device is sent to the first network device for determination of a starting position of the second sub-region in the subframe.

20. The method of claim 19, wherein receiving the resource allocation indication comprises:

the resource allocation indication indicating the starting position of the second sub-region is received.

21. The method of claim 20, wherein the starting position of the second sub-region is a third symbol in the subframe.

22. The method of claim 20, wherein the starting position of the second sub-region is a fourth symbol in the subframe.

23. The method of claim 17, wherein receiving the other DCI and the DCI comprises:

receiving first coded DCI and second coded DCI; and

decoding the first encoded DCI and the second encoded DCI with a predetermined space-time block code to obtain the other DCI and the DCI.

24. The method of claim 15, wherein receiving the first indication comprises:

the first indication is received in a control region in the first subframe.

25. The method of claim 15, wherein receiving the first indication comprises:

the first indication is received in a data region in the first subframe.

26. The method of claim 15, further comprising:

determining, in response to success of decoding the first indication, whether the downlink transmission is acceptable;

in response to determining that the downlink transmission is acceptable, sending a positive acknowledgement to the first network device indicating that the downlink transmission is acceptable; and

in response to determining that the downlink transmission is unacceptable, a negative acknowledgement is sent to the first network device indicating that the downlink transmission is denied.

27. The method of claim 26, further comprising:

the first indication is received in a third subframe subsequent to the first subframe in response to sending the negative acknowledgement indicating that the downlink transmission was denied.

28. The method of claim 15, further comprising:

Transmitting a first uplink reference signal to the second network device for measurement of a first quality of a first uplink channel between the second network device and the terminal device;

transmitting a second uplink reference signal to a third network device for measurement of a second quality of a second uplink channel between the third network device and the terminal device;

in response to receiving information from the first network device regarding a pair of uplink beams associated with the first quality, performing a measurement of a third quality of a downlink channel between the second network device and the terminal device; and

an indication of the third quality is sent to the first network device for use in deciding on a cooperative downlink transmission from the first network device and the second network device to the terminal device.

29. A method of communication, comprising:

measuring, at a second network device, a first quality of a first uplink channel between the second network device and a terminal device served by a first network device;

transmitting an indication of the first quality and information about a pair of uplink beams associated with the first quality to the first network device;

In response to receiving an indication from the first network device to initiate a measurement of a quality of a downlink channel between the second network device and the terminal device, transmitting a downlink reference signal for the measurement to the terminal device; and

an indication is received from the first network device that the second network device is selected for cooperative downlink transmission to the terminal device in response to the quality of the downlink channel exceeding a first threshold quality.

30. The method of claim 29, further comprising:

the downlink transmission is initiated in response to receiving a positive acknowledgement from the terminal device indicating that the downlink transmission from the second network device is accepted.

31. A network device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to perform the method of any one of claims 1 to 13.

32. A network device, comprising:

At least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to perform the method of claim 14.

33. A terminal device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal device to perform the method of any of claims 15 to 28.

34. A network device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code are configured to, with the at least one processor, cause the network device to perform the method of any of claims 29 to 30.

35. An apparatus for communication, comprising:

means for selecting, at a first network device serving a terminal device, a second network device for cooperative downlink transmission to the terminal device;

Means for transmitting, to the terminal device on a downlink data channel, a resource allocation indication for downlink control information, DCI, and information regarding decoding of the DCI, the DCI being associated with the second network device;

means for determining whether a link between the first network device and the second network device is an ideal backhaul or a non-ideal backhaul; and

a component for: i) Transmitting the DCI to the terminal device on at least a first downlink control channel between the first network device and the terminal device in response to determining that the link is the ideal backhaul, or ii) transmitting a first indication to the terminal device in a first subframe that a downlink transmission from the second network device is to be initiated in response to determining that the link is the non-ideal backhaul link.

36. An apparatus for communication, comprising:

means for comparing a first quality of a first uplink channel between a second network device and a terminal device served by the first network device with a second quality of a second uplink channel between a third network device and the terminal device;

Means for sending, in response to the first quality being higher than the second quality, an indication to the second network device of: initiate a measurement of a third quality of a downlink channel between the second network device and the terminal device;

means for transmitting information about a pair of uplink beams associated with the first quality to the terminal device;

means for receiving an indication of the third quality from the terminal device; and

means for transmitting an indication to the second network device that the second network device is selected for cooperative downlink transmission to the terminal device in response to determining that the third quality exceeds a first threshold quality.

37. An apparatus for communication, comprising:

means for receiving, on a downlink data channel between a first network device and a terminal device, a resource allocation indication for downlink control information, DCI, associated with a second network device and information regarding decoding of the DCI; and

a component for: i) Means for receiving the DCI on a first downlink control channel between the first network device and the terminal device in response to determining that the resource allocation indication indicates resources on the first downlink control channel, or ii) means for receiving a first indication from the first network device that a downlink transmission from the second network device is to be initiated in a first subframe in response to determining that the resource allocation indication indicates resources on a second downlink control channel between the second network device and the terminal device.

38. An apparatus for communication, comprising:

means for measuring, at a second network device, a first quality of a first uplink channel between the second network device and a terminal device served by a first network device;

means for transmitting an indication of the first quality and information about a pair of uplink beams associated with the first quality to the first network device;

means for transmitting a downlink reference signal for a measurement of a quality of a downlink channel to the terminal device in response to receiving an indication from the first network device to initiate the measurement, the downlink channel being between the second network device and the terminal device; and

means for receiving, from the first network device, an indication that the second network device is selected for cooperative downlink transmission to the terminal device in response to the quality of the downlink channel exceeding a first threshold quality.

39. A computer readable medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the method according to any of claims 1 to 13.

40. A computer readable medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the method according to claim 14.

41. A computer readable medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the method of any of claims 15 to 28.

42. A computer readable medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the method of any of claims 29 to 30.