Beamforming Solutions for MIMO Communication

Abstract

Exemplary embodiments of the present disclosure relate to on-demand labeling for channel classification training. A first device transmits a first signal from the first device to each of a plurality of second devices via a first beam. From each of the plurality of second devices, a second signal transmitted via a second beam determined based on the first beam is received, and the first beam is adjusted based on a measurement result of the received second signal, whereby the first device also updates the first beam at least once. In this way, instead of achieving the maximum beamforming gain for a pair of a one-to-one network device and a terminal device, the total beamforming gain between a plurality of network devices and a plurality of terminal devices is optimized.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and more specifically, to beamforming solutions for multiple-input multiple-output (MIMO) systems.

Background Art

[0002] To meet the increasing demand for wireless data traffic, multiple methods have been proposed and implemented, and MIMO technology is considered one of the powerful methods to achieve high data throughput in communication systems. MIMO refers to a type of wireless transmission and reception method in which both the transmitter and the receiver use multiple antennas. Further, in a MIMO system, before communicating with a network device, a terminal device needs to perform analog beamforming and beam alignment procedures. Therefore, beamforming and beam alignment technologies are important in MIMO systems.

Summary of the Invention

[0003] In a first aspect of the present disclosure, a first device is provided. The first device includes at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the first device to perform at least the steps of transmitting a first signal from the first device to each of a plurality of second devices via a first beam, receiving a second signal transmitted via a second beam determined based on the first beam from each of the plurality of second devices, and adjusting the first beam based on a measurement result of the received second signal, thereby updating the first beam at least once.

[0004] In a second aspect of the present disclosure, a second device is provided. The second device includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the second device to perform at least the steps of receiving, from each of a plurality of first devices, a first signal transmitted via a first beam determined by each respective first device; adjusting a second beam based on measurement results of the received first signal; and transmitting a second signal to the first device via the second beam, thereby determining a second beam used by the second device to communicate with the first device at least once.

[0005] In a third aspect of the present disclosure, a third device is provided. The third device includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the third device to perform at least the steps of generating a configuration related to at least one of a first signal transmitted by a first device that is a beam alignment initiator or a second signal transmitted by a second device that is a beam alignment coordinator; and transmitting the configuration to one of the first device and the second device that is a network device connected to the third device.

[0006] In a fourth aspect of the present disclosure, a method is provided. In a first device, the method includes updating the first beam at least once by transmitting a first signal from the first device to each of a plurality of second devices via a first beam; receiving, from each of the plurality of second devices, a second signal transmitted via a second beam determined based on the first beam; and adjusting the first beam based on measurement results of the received second signal.

[0007] In a fifth aspect of the present disclosure, a method is provided. The method includes, at a second device, receiving, from each of a plurality of first devices, a first signal transmitted via a first beam determined by each respective first device; determining, at the second device, to communicate with the first device at least once using a second beam by the second device; adjusting the second beam based on a measurement result of the received first signal; and transmitting a second signal to the first device via the second beam.

[0008] In a sixth aspect of the present disclosure, a method is provided. The method includes, at a third device, generating a configuration related to at least one of a first signal transmitted by a first device that is a beam alignment initiator or a second signal transmitted by a second device that is a beam alignment coordinator; and transmitting the configuration to one of the first device and the second device that is a network device connected to the third device.

[0009] In a seventh aspect of the present disclosure, a first apparatus is provided. The first apparatus includes at least means for transmitting a first signal to each of a plurality of second devices via a first beam; and means for receiving, from each of the plurality of second devices, a second signal transmitted via a second beam determined based on the first beam, and updating the first beam at least once by adjusting the first beam based on a measurement result of the received second signal.

[0010] In an eighth aspect of the present disclosure, a second apparatus is provided. The second apparatus includes means for receiving, from each of a plurality of first devices, a first signal transmitted via a first beam determined by each respective first device; and means for determining, at the second device, a second beam used by the second device to communicate with the first device at least once by adjusting the second beam based on a measurement result of the received first signal; and means for transmitting a second signal to the first device via the second beam.

[0011] In a ninth aspect of the present disclosure, a third device is provided. The third device includes means for generating a configuration related to at least one of a first signal transmitted by a first device that is an initiator of beam alignment or a second signal transmitted by a second device that is a coordinator of beam alignment in the third device, and means for transmitting the configuration to one of the first device and the second device that is a network device connected to the third device.

[0012] In a tenth aspect of the present disclosure, a computer-readable medium is provided. The computer-readable medium includes stored instructions for causing a device to execute a method according to at least the first aspect.

[0013] In an eleventh aspect of the present disclosure, a computer-readable medium is provided. The computer-readable medium includes stored instructions for causing a device to execute a method according to at least the second aspect.

[0014] In a twelfth aspect of the present disclosure, a computer-readable medium is provided. The computer-readable medium includes stored instructions for causing a device to execute a method according to at least the third aspect.

[0015] It should be understood that the section "Summary of the Invention" is not intended to identify the main or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will be readily understood from the following description.

[0016] Hereinafter, embodiments will be described with reference to the drawings. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. Throughout the drawings, the same or similar reference numerals represent the same or similar elements.

Brief Description of the Drawings

[0017]

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[0018] Next, the principles of the present disclosure will be described with reference to some exemplary embodiments. These embodiments are described for illustrative purposes only and are intended to assist those skilled in the art in understanding and implementing the present disclosure, but it should be understood that they do not imply any limitation with respect to the scope of the present disclosure. The embodiments described herein can be implemented in various ways other than those described below.

[0019] In the following description and claims, unless otherwise defined, 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 pertains.

[0020] As used herein, terms such as "one embodiment," "an embodiment," "exemplary embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but not every embodiment need include the particular feature, structure, or characteristic. Further, such phrases are not necessarily referring to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0021] The terms "first", "second", etc. may be used herein to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0022] As used herein, "at least one of the following" is at least one and similar phrases of "a list of two or more elements" and "a list of two or more elements", and when the list of two or more elements is joined by "and" or "or", it means at least one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0023] As used herein, unless explicitly stated otherwise, performing a step in response to A does not indicate that the step is performed immediately after "A" occurs, and one or more intervening steps may be included.

[0024] The terms used herein are for the sole purpose of describing particular embodiments and are not intended to limit the exemplary embodiments. As used herein, and unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" are to be construed to include the plural forms as well. Further, the terms "comprises", "comprising", "has", "having", "includes", and / or "including", when used herein, specify the presence of the stated features, elements, and / or components, etc., but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0025] As used in this application, the term "circuit" may refer to one or more or all of the following. (a) A hardware-only circuit implementation (such as an implementation only in analog and / or digital circuits) (b) A combination of a hardware circuit and software, where applicable, (i) A combination of analog and / or digital hardware circuits and software / firmware (ii) Any portion of software, software, and a hardware processor (including a digital signal processor) that cooperate to cause a device such as a mobile phone or a server to perform various functions (c) A hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, that requires software (e.g., firmware) for operation, but the software may not be present when not required for operation.

[0026] This definition of a circuit applies to all uses of this term in this application, including any claims. As a further example, as used in this application, the term "circuit" also includes simply a hardware circuit or processor (or processors), or a portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware implementation. The term "circuit" also includes, for example, a baseband integrated circuit or a processor integrated circuit for a mobile device, or a similar integrated circuit within a server, a cellular network device, or other computing or network device, if applicable to the elements of a particular claim.

[0027] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard such as NR (New Radio), LTE (Long Term Evolution), LTE-A (LTE-Advanced), WCDMA (registered trademark) (Wideband Code Division Multiple Access), HSPA (High-Speed Packet Access), NB-IoT (Narrow Band Internet of Things). Further, the communication between the terminal device and the network device in the communication network can be carried out according to any suitable generation of communication protocol, including but not limited to the communication protocols of the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), and / or any other protocol known currently or developed in the future. Embodiments of the present disclosure can be applied to various communication systems. Considering the rapid development of communication, it is natural that there will also be future types of communication technologies and systems to which the present disclosure can be embodied. This should not be understood as limiting the scope of the present disclosure to only the aforementioned systems.

[0028] As used herein, the term "network device" refers to a node within a communication network from which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), such as Node B (NodeB or NB), evolved Node B (eNodeB or eNB), NR NB (also called gNB), remote radio unit (RRU), radio header (RH), remote radio head (RRH), relay, integrated access and backhaul (IAB) node, low-power nodes such as femto, pico, non-terrestrial network (NTN) or non-terrestrial network devices such as satellite network devices, low Earth orbit (LEO) satellites and geosynchronous Earth orbit (GEO) satellites, aircraft network devices, etc., depending on the terms and technologies applied. In some exemplary embodiments, a radio access network (RAN) split architecture includes a central unit (CU) and a distributed unit (DU) at an IAB donor node. The IAB node includes a mobile terminal (IAB-MT) portion that behaves like a UE towards the parent node and a DU portion of the IAB node that behaves like a base station towards the next-hop IAB node.

[0029] The term "terminal device" refers to any end device that can be capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). A terminal device includes, but is not limited to, a mobile phone, a cellular phone, a smartphone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded equipment (LEE), a laptop-mounted equipment (LME), a USB dongle, a smart device, a wireless customer premise equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., remote surgery), an industrial device and application (e.g., a robot and / or other wireless device operating in an industrial and / or automated processing chain context), a home electronic device, a device operating on a commercial and / or industrial wireless network, etc. A terminal device may also correspond to the mobile terminal (MT) portion of an IAB node (e.g., a relay node). In the following description, the terms "terminal device", "communication device", "terminal", "user equipment", and "UE" may be used interchangeably.

[0030] As used herein, the terms "resource", "transmission resource", "resource block", "physical resource block (PRB)", "uplink resource", or "downlink resource" may refer to any resource for performing communication between a terminal device and a network device, such as a resource in the time domain, a resource in the frequency domain, a resource in the spatial domain, a resource in the code domain, or any other resource enabling communication. Hereinafter, unless explicitly stated otherwise, resources in both the frequency domain and the time domain are used as examples of transmission resources for explaining some exemplary embodiments of the present disclosure. It should be noted that the exemplary embodiments of the present disclosure are equally applicable to other resources in other domains.

[0031] The functions described herein can be performed in various exemplary embodiments in fixed and / or wireless network nodes, while in other exemplary embodiments, the functions may be implemented in a user equipment device (e.g., a mobile phone, a tablet computer, a laptop computer, a desktop computer, a mobile IoT device, or a fixed IoT device). Such a user equipment device can be equipped with corresponding capabilities as described, for example, in relation to fixed and / or wireless network nodes as appropriate. The user equipment device may be a control device such as a chipset or a processor that is configured to control the user equipment when installed in the user equipment and / or therein. Examples of such functions include a bootstrapping server function and / or a home subscriber server, which can be implemented in the user equipment device by providing software configured to cause the user equipment device to execute from the perspective of these functions / nodes.

[0032] Millimeter-wave / terahertz communication is expected to be supported so that more communication resources can be available for wireless communication. However, millimeter-wave / terahertz communication always has coverage problems due to propagation limitations such as large path loss, easy blockage, and shadowing. A network architecture called a distributed / self-free MIMO network has been discussed by the large-scale MIMO and terahertz working groups of International Mobile Telecommunications (IMT)-2030 (6th generation, 6G). In a distributed / self-free MIMO network, instead of using single and co-located large antenna arrays, multiple large arrays with smaller dimensions in a hybrid architecture can be efficiently deployed over multiple access points (APs) in a distributed manner by exploring macro-diversity from distributed APs.

[0033] In the case of cellular / small cells, the beam management procedure aims to achieve the maximum beamforming gain. In some cases, each terminal device executes a beam alignment procedure individually with its serving network device (such as a gNB). In summary, in a single-cell MIMO system, beam management aims at the best beam between the gNB and each terminal device, which is achieved by transmitting beam sweeping and the feedback of the terminal device for beam selection to obtain the best beam for the terminal device.

[0034] Distributed / self - contained MIMO networks are expected to be able to support communication at millimeter - wave and sub - terahertz frequencies. Specifically, at millimeter - wave and sub - terahertz frequencies, terminal devices are equipped with multiple antennas and a hybrid array architecture, which requires analog beamforming in the terminal device and beam alignment with network devices (such as APs). Therefore, in distributed / self - contained MIMO, it is desired to design how to perform distributed analog beamforming at each AP so that beam alignment between a cooperating AP and the corresponding serving UE can be effectively executed.

[0035] However, in a distributed or self - contained MIMO network, multiple APs serve multiple terminal devices simultaneously, but the goal of beamforming is to maximize the total beamforming gain, and when each terminal device aligns its analog beam with each AP, the maximum total beamforming gain cannot be achieved.

[0036] When a legacy beam alignment procedure is applied in a distributed MIMO network or a self - contained MIMO network, the AP performs beam sweeping (cell - specific), and each terminal device feeds back the number of some beam identification (ID) for its serving AP. In this case, the number of beams is proportional to the number of UEs served simultaneously at each AP, which is either not practical because it requires a sufficient number of radio - frequency (RF) chains at each AP to support all its serving terminal devices or the beams are not commonly optimized to achieve the total beamforming gain. Furthermore, the terminal device also needs to determine its received analog beam from the channels of the combined serving APs instead of each individual AP, which is also a technical point under consideration.

[0037] In view of the above, it is desirable to propose an efficient beam alignment mechanism for a distributed / self-free MIMO system that can meet the analog beamforming requirements of terminal devices equipped with multiple antennas and hybrid arrays.

[0038] According to the present disclosure, a beamforming solution for a MIMO system is provided. In the present disclosure, each of a plurality of first devices transmits a respective first signal to a plurality of second devices via respective first beams, and each of the plurality of second devices measures the first signal to determine a respective second beam. Then, each of the plurality of second devices transmits a respective second signal to the plurality of first devices via the determined second beams. Then, each of the plurality of first devices updates its respective first beam based on the received second signal. In this way, instead of achieving the maximum beamforming gain for a pair of one-to-one network devices and terminal devices, the total beamforming gain between a plurality of network devices and a plurality of terminal devices is optimized.

[0039] To facilitate the discussion, some terms used in the following description are listed below. ● First device: The initiator during beam alignment, and the first device triggers beam alignment. ● First beam: One or more beams used or to be used by the first device. ● First signal: The signal transmitted by the first device. The first signal can be distributed over different transmission resources. ● Second device: The coordinator during beam alignment. ● Second beam: One or more beams used or to be used by the second device. ● Second signal: The signal transmitted by the second device. The second signal can be distributed over different transmission resources.

[0040] [Exemplary Environment] FIG. 1 shows an exemplary communication environment 100 in which an exemplary embodiment of the present disclosure may be implemented. In communication environment 100, a plurality of communication devices including a plurality of first devices 110-1, 110-2, ···, 110-P and a plurality of second devices 120-1, 120-1, ···, 120-Q are involved, and both P and Q are greater than 2. For the purpose of explanation, the first devices 110-1, 110-2, ···, 110-P are collectively or individually referred to as the first device 110, and the second devices 120-1, 120-1, ···, 120-Q are collectively or individually referred to as the second device 120.

[0041] In a specific embodiment, each first device 110 can communicate with a plurality of second devices 120 via a physical communication channel or link, and each second device 120 can in turn communicate with a plurality of first devices 110 via a physical communication channel or link. It is clarified that different first devices 110 can communicate with a plurality of different second devices 120, and different second devices can also communicate with a plurality of different first devices 110 in the same manner.

[0042] Furthermore, distributed / self-free MIMO technology is supported. Specifically, each first device 110 can communicate with a plurality of second devices 120 via one or more first beams to enable directional communication, and each second device 120 can also communicate with a plurality of first devices 110 via one or more second beams to enable directional communication.

[0043] Optionally, communication environment 100 also includes a third device 130 responsible for resource scheduling and network management. As a specific embodiment, the third device is a central processing unit (such as a central processing unit, CPU, etc.). As another specific embodiment, the third device can be a core network (CN) device.

[0044] In some exemplary embodiments, the first device 110 is a network device (such as an AP) to which the first device 110 is connected to the third device 130. In this case, the third device 130 can send configurations and information to the first device 110, and the first device 110 can optionally forward the received configurations and information to the second device 120 (such as a terminal device). Alternatively, in some exemplary embodiments, the second device 120 is a network device (such as an AP), and the second device 120 is connected to the third device 130. In this case, the third device 130 can send configurations and information to the second device 120, and the second device 120 can optionally forward the received configurations and information to the first device 110 (such as a terminal device).

[0045] It should be understood that the number of devices shown in FIG. 1 and their connections are for illustrative purposes only and do not imply any limitations. The communication environment 100 may include any suitable number of devices adapted to implement the embodiments of the present disclosure. For example, the number of the first device 110, the second device 120, and the third device 130 and their connections are for illustrative purposes only and do not imply any limitations. The communication environment 100 may include any suitable first device 110, second device 120, and third device 130 adapted to implement the embodiments of the present disclosure. Further, although not shown, it should be understood that one or more additional first devices, second devices, and third devices may be disposed within their respective cells.

[0046] [Principle of Operation and Signaling Flow Example] Exemplary embodiments of the present disclosure will be described in detail below with reference to FIG. 2 showing a signaling flow 200 for communication according to some exemplary embodiments of the present disclosure. For the sake of explanation, the signaling flow 200 will be described with reference to FIG. 1.

[0047] As shown in FIG. 2, the signaling flow 200 involves a first device 110 (from the first device 110-1 to the first device 110-P), a second device 120 (from the second device 120-1 to the second device 110-Q), and a third device 130. For the sake of explanation, refer to FIG. 1 to describe the signaling flow 200.

[0048] In the following text, although the description will be discussed with respect to one specific first device 110 (such as the first device 110-1) and one specific second device 120 (such as the second device 120-1), it should be understood that in some cases, all the first devices 110 / second devices 120 are similar. That is, the description discussed with respect to a particular first device 110 should be considered applicable to other first devices 110, and the description discussed with respect to a particular second device 120 should be considered applicable to other second devices 120. For simplicity, some similar content is omitted in this specification.

[0049] It is also clear that in the following description, different first devices 110 can communicate with different second devices 120, and different second devices can also communicate with different first devices 110.

[0050] In some exemplary embodiments, the first device 110 is a network device, the second device 120 is a terminal device, and the third device 130 is a central processing device.

[0051] Alternatively, in some exemplary embodiments, the first device 110 is a terminal device, the second device 120 is a network device, and the third device 130 is a central processing device.

[0052] During operation, the first device 110-1 transmits a first signal to the second device 120 via a first beam (215). In some exemplary embodiments, the first device 110-1 transmits the first signal in a broadcast or multicast manner.

[0053] In addition, each of the other first devices 110-1 to 110-P also transmits its respective first signal to the second device 120 via its respective first beam (215).

[0054] In some exemplary embodiments, the first beam can be initially determined by each respective first device based on any suitable method (210). In one particular exemplary embodiment, the first beam is initially determined as a predetermined beam such as the most recently used beam, the most frequently used beam, a beam having a simple beamforming matrix, etc. It should be understood that the above examples of predetermined beams are for illustration only and do not imply any limitation. In other exemplary embodiments, the first beam is initially determined as any other suitable predetermined beam. The present disclosure is not limited in this regard.

[0055] Alternatively, in another particular exemplary embodiment, the first beam is initially determined as a randomly obtained beam. For example, a random beam selection mechanism (such as a random DFT-based beam) can be used to initially determine the first beam. It should be understood that other random beam selection mechanisms can also be used to initially determine the first beam in other exemplary embodiments. The present disclosure is not limited in this regard.

[0056] In some exemplary embodiments, the first signal is a reference signal / pilot such as a channel state information (CSI)-reference signal (RS), CSI-RS, and sounding reference signal (SRS).

[0057] In some exemplary embodiments, the first beam is initially determined as a wide beam. In this way, the first signal transmitted via the first beam can be more easily detected by the second device 120.

[0058] Based on the first signal, each second device 120 can determine its respective second beam that is used by the second device 120 to communicate with its associated first device 110 (220-1).

[0059] As shown in FIG. 2, the second device 120-1 receives the first signal from each of the first devices 110 and adjusts its respective second beam based on the measurement results of the received first signal.

[0060] In this way, the second beam used by the second device can be determined without any feedback from the second device 120-1 to the first device 110.

[0061] In some exemplary embodiments, the second device 120-1 adjusts the second beam to increase the beamforming gain in the second device 120 for all its associated first devices 110. In one particular exemplary embodiment, the second device 120-1 receives the first signal by beam sweeping and determines which beam has a higher beamformer gain than at least one other beam. Based on the results of the beam sweeping, the second beam can be determined. Additionally, in some exemplary embodiments, the second device 120-1 adjusts the second beam to a beam that enables the maximum beamforming gain in the second device 120-1 for all its associated first devices 110.

[0062] In this way, since the second beam is determined based on the first signals from the plurality of first devices 110, the total beamforming gain at the system level is maximized.

[0063] In some exemplary embodiments, the first signal is transmitted simultaneously by the first device 110. In this way, each second device 120 can receive all the signals that need to be measured at once, which saves the power consumption of the second device and thus improves network performance.

[0064] In some exemplary embodiments, the first signal is periodic. In this way, each second device 120 may select an inappropriate opportunity to receive the first signal, which allows for a more flexible reception of the first signal.

[0065] In some exemplary embodiments, the first device 110 can update the first beam determined initially (230-1), which can be achieved by measuring the second signal transmitted by the second device 120. As shown in FIG. 2, the first device 110-1 receives the second signal from each of its associated second devices 120 (225-1) and adjusts the first beam based on the measurement results of the received second signal.

[0066] Similar to the operation of determining the second beam in the second device 120, in some exemplary embodiments, the first device 110-1 adjusts the first beam to increase the beamforming gain at the first device 110-1 for all its associated second devices 120. In one particular exemplary embodiment, the first device 110-1 receives the second signal by beam sweeping and determines which beam has a higher beamforming gain than at least one other beam. Based on the results of the beam sweeping, the first beam can be updated. Additionally, in some exemplary embodiments, the first device 110-1 adjusts the first beam to the beam that enables the maximum beamforming gain at the first device 110-1 for all its associated second devices 120.

[0067] In this way, since the first beam is updated based on the second signals from the plurality of second devices 120, the total beamforming gain at the system level is maximized.

[0068] In some exemplary embodiments, the second signals are transmitted simultaneously by the second devices 120. In this way, each first device 110 can receive all the signals that need to be measured at one time, which saves the power consumption of the first device and thus improves the network performance.

[0069] Similarly for the first signals, the second signals can also be reference signals / pilots such as downlink (DL) CSI-RS, uplink (UL) SRS. Further, in some exemplary embodiments, the second signals are periodic. In this way, each first device 110 can select an appropriate opportunity to receive the second signals, which enables a more flexible reception of the second signals.

[0070] In some exemplary embodiments, the transmission of either the first signal or the second signal can be configured by a third device 130. The third device 130 can configure any appropriate parameters for the transmission of either the first signal or the second signal. An example of appropriate parameters is transmission resources such as the first transmission resource assigned to the first signal, the second transmission resource assigned to the second signal, etc. Another example of appropriate parameters is the timing for transmission such as the first timing configured for the first signal and the second timing configured for the second signal. A further example of appropriate parameters is the periodicity for transmission such as the first periodicity for transmitting the first signal and the second periodicity for transmitting the second signal. Other examples of suitable parameters include, but are not limited to, indications for transmission such as the first indication indicating that the first device 110 transmits the first signal, the second indication indicating that the second device 120 receives the first signal, etc.

[0071] It should be understood that the above examples of suitable parameters are for illustrative purposes only and do not imply any limitation. In some other exemplary embodiments, any suitable parameters may be determined by the third device 130 for the transmission of either the first signal or the second signal. The present disclosure is not limited in this regard.

[0072] In addition, the configuration can be shown in the first device 110 and the second device 120. Specifically, in some exemplary embodiments, the first device 110 is a network device and is connected to the third device 130. In this case, the third device 130 can transmit the configuration to the first device 110, and the first device 110 can further transfer the received configuration to the second device 120. Alternatively, in some exemplary embodiments, the second device 120 is a network device and is connected to the third device 130. In this case, the third device 130 can transmit the configuration to the second device 120, and the second device 120 can optionally transfer the received configuration to the first device 110.

[0073] In this way, the simultaneous transmission of either the first signal or the second signal is guaranteed.

[0074] In some exemplary embodiments, the iteration 250 may be executed to refine the first / second beam. During the iteration 250, the operation of determining the second beam may be executed multiple times (220-i) by the second device 120. As shown in FIG. 2, the second device 120 receives the first signal from each of the first devices 110 (215-i) and adjusts each second beam based on the measurement results of the received first signal.

[0075] Therefore, during iteration 250, the operation 230-i of updating the first beam can be executed multiple times by the first device 110. As shown in FIG. 2, the first device 110 receives a second signal from each of the second devices 120 (225-i) and adjusts each first beam based on the measurement results of the received second signals.

[0076] In some exemplary embodiments, the first device 110 repeatedly updates the first beam until a first termination condition is satisfied. To control iteration 250, many factors can be used by the first termination condition. One exemplary factor is the number of iterations. Another exemplary factor is the beamforming gain of the first beam in the first device. A further exemplary factor is the difference in beamforming gain between two adjacent iterations. Other exemplary factors include, but are not limited to, an instruction to terminate the iteration (such as an instruction transmitted by the third device 130).

[0077] In one specific exemplary embodiment, the first termination condition is determined to be satisfied when the number of iterations reaches a first predetermined number. Alternatively, in another specific exemplary embodiment, the first termination condition is determined to be satisfied when the beamforming gain provided by at least one first beam in the first device is greater than or equal to a first predetermined beamforming gain. Alternatively, in another specific exemplary embodiment, the first termination condition is determined to be satisfied when the difference in beamforming gain between two adjacent iterations is less than or equal to a first predetermined gain difference. Alternatively, in another specific exemplary embodiment, the first termination condition is determined to be satisfied when a third instruction indicating that the first device terminates the iteration is received.

[0078] It should be understood that the above exemplary factors are for illustration purposes only without suggesting any limitation. In other exemplary embodiments, any suitable deterministic configuration parameters and dynamic measurements in the first and second devices may be associated with the first termination condition.

[0079] Similarly, in some exemplary embodiments, the second device 120 repeatedly determines the second beam until the second termination condition is met. Similar to the first termination condition, the second termination condition may also be related to one or more of the number of iterations, the beamforming gain of the second beam in the second device, the beamforming gain difference between two adjacent iterations, or an instruction to terminate the iteration (such as an instruction transmitted by the third device 130). For the sake of brevity, similar content is omitted here.

[0080] In some exemplary embodiments, the first device 110 and the second device 120 share a common termination condition, which means that the first and second termination conditions are the same. Alternatively, the first and second termination conditions are defined independently, which means that the first and second termination conditions may be different.

[0081] In some exemplary embodiments, the first and second termination conditions are default configurations. In this case, the first and second termination conditions may be implemented as local configurations in the first and second devices. Therefore, no additional signaling exchange from the third device 130 is required.

[0082] Alternatively, the first and second termination conditions are determined by the third device 130 and notified to the first device 110 and the second device 120. The transmission procedure for the first and second termination conditions is similar to the configuration of the first and second signals. For the sake of brevity, similar content is omitted here.

[0083] In some exemplary embodiments, whether to terminate iteration 250 is determined by the first device 110 / second device 120 according to the first / second termination conditions. Alternatively, whether to terminate iteration 250 is determined by the third device 130. As shown in FIG. 2, the first device 110 / second device 120 can transmit the measurement results of the second / first signal to the third device 130. The third device 130 determines whether to terminate iteration 250 based on the measurement results and / or the first / second termination conditions. If the third device 130 determines to terminate iteration 250, the third device 130 may generate an instruction to instruct the first device 110 / second device 120 to terminate iteration 250.

[0084] In some exemplary embodiments, the state of iteration 250 should be consistent among the first device 110, the second device 120, and the third device 130. Thus, once it is determined that iteration 250 is to be started or terminated, the first device 110, the second device 120, and the third device 130 should exchange messages with each other to ensure that the status of iteration 250 is consistent.

[0085] As described above, the first device 110-1 or the second device 120-1 recovers the second signal and the first signal by beam sweeping. In some exemplary embodiments, the beam sweeping procedure can be optimized during iteration 250. Specifically, the number of beams in the beam sweeping decreases as the number of iterations increases. This is because after the original beam sweeping, the first device 110-1 and the second device 120-1 can understand the overall angular coverage in some cases so that subsequent beam sweepings can be within the overall angular coverage. In this way, the power consumption caused by unnecessary beam sweepings is avoided.

[0086] Next, the first device 110 and the second device 120 can perform transmissions to each other (270) (including data, RS, etc.).

[0087] According to the exemplary process described above, a beam alignment mechanism in a distributed / self-free MIMO is enabled. According to some exemplary embodiments of the present disclosure, maximization of the total effective array gain between the first device 110 and the second device 120 is achieved, approaching full digital performance.

[0088] In addition, the present disclosure does not require increasing the number of RF chains, and is simpler, more convenient, and implementable.

[0089] Furthermore, beam alignment can be periodically triggered in a communication system. In this way, even when the channel state changes and the terminal device moves, the total beamforming gain can be guaranteed.

[0090] [Discussion on one specific scenario] To better understand the solution of the present disclosure, an exemplary process is described with respect to one specific scenario. In the specific scenario, a self-free MIMO network is supported, and the self-free MIMO network includes M APs and K terminal devices, where M and K are greater than 2.

[0091] The M APs are indexed as AP1, …, APm, …, APM (m is the index of the AP, m = 1, …, M), and the K terminal devices are indexed as terminal device 1, …, terminal device k, …, terminal device K (k is the index of terminal device k = 1, …, K).

[0092] For the purpose of discussion, AP1, …, APm, …, APM are collectively or individually referred to as APs, and terminal device 1, …, terminal device k, …, terminal device K are collectively or individually referred to as terminal devices.

[0093] Distributed analog beamforming is performed at each AP. For APm and terminal device k, the analog beamforming matrices are denoted as Fm and Wk, respectively.

[0094] In some exemplary embodiments, to achieve good beam alignment, the beamforming procedure can be designed to maximize the total beamforming gain or effective array gain in a self-free MIMO network. In some exemplary embodiments, the maximization problem can be formulated by Equation (1) below.

Number

Number

Number

Number

Number

[0095] In some exemplary embodiments, to solve the above maximization problem, it is efficient to perform the alternating calculation of the analog beamformer and combiner between the AP and the terminal device in a cooperative manner.

[0096] In some exemplary embodiments, a fixed

Number

Number

Number

Number

[0097] In some exemplary embodiments, using a fixed

Number

Number

Number

Number

[0098] As described above, the first device 110 (i.e., the initiator) can be either an AP or a terminal device. The following describes the above two cases separately.

[0099] [Exemplary scenario where the initiator is an AP] Exemplary embodiments are described in detail below with reference to FIGS. 3A and 3B, where FIG. 3A shows another signaling flow 300 for communication according to some exemplary embodiments of the present disclosure, and FIG. 3B shows a transmission timing 350 according to some exemplary embodiments of the present disclosure. The signaling flow 300 and the transmission timing 350 include AP1 to APM and terminal devices 1 to terminal device K.

[0100] As shown in FIG. 3A, during the initialization phase, the APs (AP1 to APM) simultaneously transmit a first signal (such as a DL pilot, CSI-RS, etc.) via an initialized AP-specific common beam m (i.e., the first beam) (305).

[0101] In some exemplary embodiments, the simultaneous transmission from the AP is scheduled by a CPU (i.e., the third device). In one particular embodiment, the CPU schedules one or more of the transmission resources, transmission timing, and periodicity of the first signal (such as CSI-RS).

[0102] In some exemplary embodiments, the initialized AP-specific common beam is determined at each AP. In one particular exemplary embodiment, the initialized AP-specific common beam is, for example

Number

[0103] Alternatively, in some exemplary embodiments, a random DFT-based beam can be used to initialize the AP-specific common beam. The DFT initialization beam

Number

[0104] In some exemplary embodiments, in the initialization phase, the AP can broadcast the first signal (semi) periodically by the initialized first beam so that the terminal device can perform measurements of the first signal received in its dedicated time slot. As shown in Figure 3B, terminal device 1 can receive the first signal in the first duration, and terminal device K can receive the first signal in either the first duration or the second duration. The periodic transmission of the first signal also helps to improve coverage as the terminal device can apply time averaging to the measurement of the first signal.

[0105] In some exemplary embodiments, the AP triggers its serving terminal devices 1 to K to apply beam measurements (such as beam sweeping) to receive the first signal transmitted by the beam initialized from the AP. Each of terminal devices 1 to K determines its respective second beam, i.e., terminal device 1 determines its respective second beam (310 - 1), and terminal device K determines its respective second beam accordingly (310 - K).

[0106] In some exemplary embodiments, by using the received beam measurement values, the terminal device selects a terminal - device - specific common beam (i.e., the second beam represented as W k (c) ) that is optimal for all of its serving APs. In one particular exemplary embodiment, the terminal - device - specific common beam W k (c) can be obtained by solving the optimization problem of Equation (1) using beam sweeping.

Number

[0107] In this way, the selected common beam for the terminal device maximizes the beamforming gain from all its serving APs. As shown in Figure 3A, the terminal device applies its common beam and simultaneously transmits a UL pilot (such as SRS) to its serving AP (315). Then, each terminal device transmits a second signal (such as UL RS, SRS) (315). In some exemplary embodiments, the CPU may also configure the next SRS transmission of the terminal device via the AP, such as transmission resources, transmission timing, and periodicity.

[0108] In some exemplary embodiments, each AP receives and measures the UL pilot, and then selects a common beam dedicated to the AP (i.e., the updated first beam) that is optimal for all serving terminal devices. In one particular exemplary embodiment, the common beam F for the AP m (c) can be obtained by solving the optimization problem of Equation (2) using beam sweeping.

Number

Number

[0109] In some exemplary embodiments, the iteration may be used to further align the AP - specific common beam and the terminal - device - specific common beam. As shown in FIG. 3A, the operations at 310 - 1, 310 - K, 315, 320 - 1, 320 - M, and 325 may be executed repeatedly. In some exemplary embodiments, the iteration termination criterion (i.e., the first termination condition or the second termination condition) is configured by the CPU. In some exemplary embodiments, the iteration termination criterion is based on the deterministic configuration of the network. As an example, the termination criterion may be configured by the CPU to be a threshold number of iterations according to historical statistics.

[0110] Alternatively, in some exemplary embodiments, the iteration termination criterion is based on dynamic measurement values at each AP and / or terminal device. As an example, whether to terminate the iteration can be determined based on the measurement results at the AP. For example, each AP can measure the effective beamforming gain according to the following formula (3).

Number

[0111] Each AP can further determine the beamforming gain difference by the following formula (4).

Number

[0112] Each AP may determine to terminate the iteration when the beamforming gain difference is smaller than the threshold difference.

[0113] Alternatively, whether to terminate the iteration may be determined by the CPU. As an example, each AP transmits the beamforming gain difference to the CPU. After collecting all the beamforming gain differences from M APs, the CPU

Number

[0114] It should be understood that whether to abort the iteration can also be determined based on the measurement results at the terminal device. For the sake of brevity, similar content is omitted here.

[0115] In some embodiments, it is not necessary to sweep all beams in each iteration. In one particular exemplary embodiment, measuring the received pilot may be performed by sweeping over all beams during the original beam sweep, and the pilot may be transmitted via a wide beam. In the following beam sweep, either the terminal device or the AP already knows the general angular coverage, and subsequent beam alignment using narrow beams is performed within the general angular coverage.

[0116] Next, the terminal device and the AP can perform transmissions to each other (including data, RS, etc.) (330).

[0117] [Example when the first device 110 (i.e., the initiator) is a terminal device] Exemplary embodiments of the present disclosure are described in detail below with reference to FIGS. 4A and 4B. FIG. 4A shows a further signaling flow 400 for communication according to some exemplary embodiments of the present disclosure, and FIG. 4B shows another transmission timing 450 according to some exemplary embodiments of the present disclosure. The signaling flow 400 and the transmission timing 450 include AP1,..., APm,..., APM and terminal devices 1 to terminal device K.

[0118] As shown in FIG. 4A, in the initialization stage, the terminal devices (terminal devices 1 to terminal device K) simultaneously transmit a first signal (UL pilot, SRS, etc.) via an initialized terminal device - specific common beam m (i.e., the first beam) (405).

[0119] In some exemplary embodiments, the simultaneous transmissions from the terminal devices are scheduled by the CPU (i.e., the third device). In one particular embodiment, the CPU schedules the transmission resources and transmission timing of the first signal (i.e., SRS).

[0120] In some exemplary embodiments, the initialized common beam dedicated to the terminal device is determined at each terminal device. In one particular exemplary embodiment, the initialized common beam dedicated to the terminal device is, for example

Number

[0121] Alternatively, in some exemplary embodiments, a random DFT-based beam may be used to initialize the initialized common beam dedicated to the terminal device. DFT initialization beam

Number

[0122] In some exemplary embodiments, each AP selects an AP-specific common beam (i.e., the second beam) that is optimal for all serving terminal devices. That is, AP1 determines its respective second beam (410-1), and APM determines its respective second beam accordingly (410-M).

[0123] One specific exemplary embodiment, the AP dedicated common beam F m (c) can be obtained by solving the optimization problem of the above formula (2) using beam sweeping.

[0124] As shown in FIG. 4A, the AP applies its own AP dedicated common beam and simultaneously transmits a second signal (such as DL pilot, CSI-RS, etc.) to its serving terminal device (415). The terminal device receives the second signal and measures the received second signal.

[0125] In some exemplary embodiments, each terminal device selects a terminal device dedicated common beam (i.e., the updated first beam) that is optimal for all serving APs. In one specific exemplary embodiment, the terminal device dedicated common beam can be obtained by solving the optimization problem of the above formula (1) using beam sweeping.

[0126] In some exemplary embodiments, the iteration can be used to further align the AP dedicated common beam and the terminal device dedicated common beam. As shown in FIG. 4A, the operations at 410-1, 410-K, 415, 420-1, 420-M, and 425 can be executed iteratively. In some exemplary embodiments, the iteration termination criterion (i.e., the first termination condition or the second termination condition) is configured by the CPU. The configuration of the termination criterion is the same as that discussed for the exemplary scenario where the initiator is the AP. For the sake of brevity, the same content is omitted here.

[0127] Next, the terminal device and the AP can perform their transmissions to each other (including data, RS, etc.) (430).

[0128] [Simulation Results] In the following, the performance of the present disclosure with respect to the beamforming function is evaluated in the present disclosure by comparing a small cell method using a multi-antenna / hybrid array terminal device in a millimeter-wave distributed / self-free massive MIMO system. In the case of the small cell method, each terminal device is served by only one AP, and the available AP is selected based on the best channel quality. If one AP has already been selected by another terminal device, the next available AP with the second best channel quality is selected. The unselected APs become inactive.

[0129] In addition, the millimeter-wave channels are modeled at 28 GHz, and each channel link can be in one of three states, namely, in-line-of-sight, out-of-line-of-sight, and non-communicable. The probability calculations for the distance d follow respectively as below.

Number

Number

Number

Table 1

[0130] Furthermore, the simulated model is for M = 20 APs evenly distributed within a square area of dimensions 200m × 200m, with the minimum distance between any two APs set to 40m. Also, as shown in Fig. 5, terminal devices are randomly placed within this area, and an example of the distribution of APs and terminal devices within this area is shown. 1000 realizations of the fixed AP distribution and random terminal device positions are considered in the simulation. Each AP has a uniform rectangular array (URA) of size 4 × 8 and is fully connected to 4 RF chains. The average transmit power at each AP is 250 mW, and the noise power spectral density at the terminal device is -162 dBm.

[0131] Two cases of terminal device configurations are simulated. When the terminal device has two antennas Mr = 2, i.e., a full digital receiver, this corresponds to a special case where analog beamforming is not required. When each terminal device has a hybrid array, i.e., a 2 × 4 URA with 8 antenna elements (Mr = 8) and 2 RF chains, the proposed analog beamforming is applied to enhance the beamforming gain of the system.

[0132] Figs. 6A and 6B show the spectral efficiency performance 600 and 650 of the proposed analog beamforming procedure in distributed / cell-free MIMO compared to the small cell approach considering various numbers of terminal devices. Generally, it can be observed that the cell-free approach is significantly superior to the small cell counterparts by a factor of 5 - 8 and 5 - 10 at the median and 5% levels, respectively. This also shows that, using the proposed analog beamforming (Mr = 8), improved performance is obtained at the terminal device (Mr = 2) compared to the case without analog beams, especially in distributed / cell-free systems.

[0133] Therefore, it shows great potential to use the cell-free concept in millimeter waves together with the hybrid array terminal device, and the proposed analog beam alignment mechanism can provide satisfactory performance compared with the small cell approach.

[0134] The convergence performance using iterations is also evaluated. Fig. 7 shows the convergence performance 700 of the proposed beam alignment procedure versus the number of iterations, considering two beam initialization methods, i.e., the same beam or a random DFT beam. Using a random DFT beam spatial beam (which may be a wide beam covering a wide angular region and does not require prior knowledge of the angular information) as the initialization beam requires only a maximum of two iterations. When the same beamforming matrix (worst case) is used, three iterations are required to achieve convergence.

[0135] In some cases, the beam management procedure requires a procedure that includes transmit beam sweeping and receive beam sweeping, i.e., an improved selection of transmit beam sweeping. This latency of the beam management procedure has a latency equal to two iterations.

[0136] In summary, according to some embodiments, distributed beamforming and system architectures for distributed MIMO are supported, enabling smaller size and lower power consumption antenna arrays at each AP in distributed MIMO compared to collocated massive MIMO. Also, a multi-panel terminal device with multi-beam transceiver capabilities becomes possible, improving link reliability. In addition, maximizing the total effective array gain between all APs and all terminal devices approaches full digital performance. Also, since one good beam (at least one) can be found for all terminal devices, the number of RF chains does not need to be increased, i.e., there is no constraint on the number of RF chains on the AP side. Based on the criterion of maximizing the total effective array gain, the iterative procedure enables the maximization problem easily.

[0137] This disclosure is different from the technology of non-coherent joint transmission (NCJT). Specifically, in the solution of this disclosure, multi-AP / UE simultaneous transmission of pilots via pre-defined / selected beams, and triggering of multi-UE / AP simultaneous measurement of received pilots, as well as transmission and reception point (TRP) transmission beam sweeping and terminal device beam feedback procedures are not considered.

[0138] [Exemplary method] FIG. 8 shows a flowchart of an exemplary method 800 implemented in a first device according to some exemplary embodiments of this disclosure. For the purpose of discussion, method 800 is described from the perspective of the first device 110 in FIG. 1.

[0139] In block 810, the first device 110 transmits a first signal from the first device 110 to each of a plurality of second devices 120 via a first beam.

[0140] In block 820, the first device 110 receives a second signal transmitted from each of the plurality of second devices 120 via a second beam determined based on the first beam, and updates the first beam at least once by adjusting the first beam based on the measurement results of the received second signal.

[0141] In some exemplary embodiments, the first beam is initially determined as a wide beam.

[0142] In some exemplary embodiments, the first beam is initially determined as a predetermined beam or a randomly acquired beam.

[0143] In some exemplary embodiments, at least one of the first signal or the second signal is periodic.

[0144] In some exemplary embodiments, the first device 110 simultaneously receives second signals from the plurality of second devices 120.

[0145] In some exemplary embodiments, the first device 110 adjusts the first beam to increase the beamforming gain in the first device 110 with respect to a plurality of second devices 120.

[0146] In some exemplary embodiments, the first device 110 adjusts the first beam to a beam that enables a maximum beamforming gain in the first device 110 with respect to a plurality of second devices 120.

[0147] In some exemplary embodiments, the first device 110 receives a configuration generated by a third device 130 and related to at least one of the first signal or the second signal.

[0148] In some exemplary embodiments, the configuration indicates transmission resources. Alternatively, in some exemplary embodiments, the configuration indicates the timing of transmission. As an alternative, in some exemplary embodiments, the configuration indicates the periodicity for transmission. Alternatively, in some exemplary embodiments, the configuration indicates an instruction for transmission.

[0149] In some exemplary embodiments, if the first device 110 is a network device, the first device 110 further transmits the configuration to the second devices 120.

[0150] In some exemplary embodiments, the first device 110 repeatedly updates the first beam until a first termination condition is met.

[0151] In some exemplary embodiments, the first termination condition is related to the number of iterations. Alternatively, in some exemplary embodiments, the first termination condition is related to the beamforming gain of the first beam in the first device 110. Alternatively, in some exemplary embodiments, the first termination condition is related to the difference in beamforming gain between two adjacent iterations. Or, in some exemplary embodiments, the first termination condition is related to an instruction to terminate the iteration.

[0152] In some exemplary embodiments, the first device 110 receives information regarding the first termination condition determined by the third device 130.

[0153] In some exemplary embodiments, the first device 110 receives a second signal by beam sweeping, and the number of beams in the beam sweeping decreases as the number of iterations increases.

[0154] In some exemplary embodiments, the first signal and the second signal are reference signals.

[0155] In some exemplary embodiments, the first device 110 is a network device and the plurality of second devices 120 are terminal devices, or the first device 110 is a terminal device and the plurality of second devices 120 are network devices.

[0156] FIG. 9 shows a flowchart of an exemplary method 900 implemented in a first device according to some exemplary embodiments of the present disclosure. For purposes of discussion, method 900 is described from the perspective of the second device 120 of FIG. 1.

[0157] In block 910, the second device 120 receives, from each of the plurality of first devices 110, a first signal transmitted via a first beam determined by the respective first device 110, and determines a second beam for use by the second device 120 to communicate with the first device 110 at least once by adjusting the second beam based on a measurement result of the received first signal.

[0158] In block 920, the second device 120 transmits a second signal to the first device 110 via the second beam.

[0159] In some exemplary embodiments, at least one of the first signal or the second signal is periodic.

[0160] In some exemplary embodiments, the second device 120 receives the first signal from the plurality of first devices 110 simultaneously.

[0161] In some exemplary embodiments, the second device 120 adjusts the second beam to increase the beamforming gain at the second device 120 for the plurality of first devices 110.

[0162] In some exemplary embodiments, the second device 120 adjusts the second beam to a beam that enables the maximum beamformer gain at the second device 120 for the plurality of first devices 110.

[0163] In some exemplary embodiments, the second device 120 receives a configuration generated by a third device 130 and related to at least one of the first signal or the second signal.

[0164] In some exemplary embodiments, the configuration indicates transmission resources.

[0165] Alternatively, in some exemplary embodiments, the configuration indicates the timing of transmission.

[0166] Alternatively, in some exemplary embodiments, the configuration indicates periodicity for transmission.

[0167] Or, in some exemplary embodiments, the configuration indicates an instruction for transmission.

[0168] In some exemplary embodiments, if the second device 120 is a network device, the second device 120 further transmits the configuration to the first device 110.

[0169] In some exemplary embodiments, the second device 120 repeatedly determines the second beam until a second stop condition is satisfied.

[0170] In some exemplary embodiments, the second stop condition is related to the number of iterations.

[0171] Alternatively, in some exemplary embodiments, the second stop condition is related to the beamforming gain of the second beam at the second device 120.

[0172] Alternatively, in some exemplary embodiments, the second stop condition is related to the difference in beamforming gain between two adjacent iterations.

[0173] Or, in some exemplary embodiments, the second stop condition is related to an instruction to abort the iteration.

[0174] In some exemplary embodiments, the second device 120 receives information regarding the second stop condition determined by the third device 130.

[0175] In some exemplary embodiments, the second device 120 receives the first signal by beam sweeping, and the number of beams in the beam sweeping decreases as the number of iterations increases.

[0176] In some exemplary embodiments, the first signal and the second signal are reference signals.

[0177] In some exemplary embodiments, the second device 120 is a network device and the plurality of first devices 110 are terminal devices, or the second device 120 is a terminal device and the plurality of first devices 110 are network devices.

[0178] FIG. 10 shows a flowchart of an exemplary method 1000 implemented in a first device according to some exemplary embodiments of the present disclosure. For purposes of discussion, method 1000 is described from the perspective of the third device 130 of FIG. 1.

[0179] In block 1010, the third device 130 generates a configuration related to a first signal transmitted by the first device 110 that is a beam alignment initiator, or a second signal transmitted by the second device 120 that is a beam alignment coordinator.

[0180] In block 1010, the third device 130 transmits the configuration to either the first or second device 120, which is a network device connected to the third device 130.

[0181] In some exemplary embodiments, the configuration indicates transmission resources.

[0182] Alternatively, in some exemplary embodiments, the configuration indicates the timing of transmission.

[0183] As an alternative, in some exemplary embodiments, the configuration indicates the periodicity for transmission.

[0184] Alternatively, in some exemplary embodiments, the configuration indicates an instruction for transmission.

[0185] In some exemplary embodiments, the third device 130 transmits at least one of information regarding a first cancellation condition used by the first device 110 to determine whether to cancel beam alignment to either the first or second device 120, which are network devices connected to the third device 130, or information regarding a second cancellation condition used by the second device 120 to determine whether to cancel beam alignment.

[0186] In some exemplary embodiments, the third device 130 is a central processing unit, the first device 110 is a network device, the second device 120 is a terminal device, or the first device 110 is a terminal device and the second device 120 is a network device.

[0187] [Exemplary Apparatuses, Devices, and Media] In some exemplary embodiments, a first device (e.g., the first device 110 of FIG. 1) capable of performing any of the methods 800 may include means for performing each operation of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuit or a software module. The first device may be implemented as or included in the first device 110 of FIG. 1.

[0188] In some exemplary embodiments, the first device includes means for transmitting a first signal from the first device to each of a plurality of second devices via a first beam, and receiving, from each of the plurality of second devices, a second signal transmitted via a second beam determined based on the first beam, and updating the first beam at least once by adjusting the first beam based on a measurement result of the received second signal.

[0189] In some exemplary embodiments, the first beam is initially determined as a wide beam.

[0190] In some exemplary embodiments, the first beam is initially determined as a predetermined beam or a randomly obtained beam.

[0191] In some exemplary embodiments, at least one of the first signal or the second signal is periodic.

[0192] In some exemplary embodiments, the first device comprises means for simultaneously receiving the second signal from a plurality of second devices.

[0193] In some exemplary embodiments, the first device comprises means for adjusting the first beam to increase the beamforming gain at the first device with respect to a plurality of second devices.

[0194] In some exemplary embodiments, the first device comprises means for adjusting the first beam to a beam that enables a maximum beamformer gain at the first device with respect to a plurality of second devices.

[0195] In some exemplary embodiments, the first device further comprises means for receiving a configuration generated by a third device and related to at least one of the first signal or the second signal.

[0196] In some exemplary embodiments, the configuration indicates transmission resources. Alternatively, in some exemplary embodiments, the configuration indicates the timing of transmission. As an alternative, in some exemplary embodiments, the configuration indicates the periodicity for transmission. Alternatively, in some exemplary embodiments, the configuration indicates an instruction for transmission.

[0197] In some exemplary embodiments, when the first device is a network device, the first device further comprises means for transmitting the configuration to the second device.

[0198] In some exemplary embodiments, the first device further comprises means for repeatedly updating the first beam until a first stop condition is satisfied.

[0199] In some exemplary embodiments, the first stop condition is related to the number of iterations. Alternatively, in some exemplary embodiments, the first stop condition is related to the beamforming gain of the first beam in the first device. Alternatively, in some exemplary embodiments, the first stop condition is related to the beamforming gain difference between two adjacent iterations. Or, in some exemplary embodiments, the first stop condition is related to an instruction to stop the iteration.

[0200] In some exemplary embodiments, the first device further comprises means for receiving information regarding the first stop condition determined by a third device.

[0201] In some exemplary embodiments, the first device receives a second signal by beam sweeping, and the number of beams in the beam sweeping decreases as the number of iterations increases.

[0202] In some exemplary embodiments, the first signal and the second signal are reference signals.

[0203] In some exemplary embodiments, the first device is a network device and the plurality of second devices are terminal devices, or the first device is a terminal device and the plurality of second devices are network devices.

[0204] In some exemplary embodiments, a second device (e.g., the first device 120 of FIG. 1) capable of performing any of the methods 900 may comprise means for performing each operation of the method 900. The means may be implemented in any suitable form. For example, the means may be implemented in a circuit or a software module. The second device may be implemented as or included in the second device 120 of FIG. 1.

[0205] In some exemplary embodiments, the second device receives, from each of the plurality of first devices, a first signal transmitted via a first beam determined by each respective first device, and based on measurement results of the received first signal, by adjusting a second beam, the second device includes means for determining a second beam to be used by the second device for communicating with the first device at least once, and means for transmitting a second signal to the first device via the second beam.

[0206] In some exemplary embodiments, at least one of the first signal or the second signal is periodic.

[0207] In some exemplary embodiments, the second device receives the first signal from the plurality of first devices simultaneously.

[0208] In some exemplary embodiments, the second device includes means for adjusting the second beam to increase a beamforming gain at the second device with respect to the plurality of first devices.

[0209] In some exemplary embodiments, the second device includes means for adjusting the second beam to a beam that enables a maximum beamforming gain at the second device with respect to the plurality of first devices.

[0210] In some exemplary embodiments, the second device further includes means for receiving a configuration generated by a third device and related to at least one of the first signal or the second signal.

[0211] In some exemplary embodiments, the configuration indicates transmission resources.

[0212] Alternatively, in some exemplary embodiments, the configuration indicates the timing of transmission.

[0213] As an alternative, in some exemplary embodiments, the configuration indicates periodicity for transmission.

[0214] Alternatively, in some exemplary embodiments, the configuration indicates an instruction to transmit.

[0215] In some exemplary embodiments, if the second device is a network device, the second device further transmits the configuration to the first device.

[0216] In some exemplary embodiments, the second device repeatedly determines the second beam until a second stop condition is met.

[0217] In some exemplary embodiments, the second stop condition is related to the number of iterations.

[0218] Alternatively, in some exemplary embodiments, the second stop condition is related to the beamforming gain of the second beam at the second device.

[0219] Alternatively, in some exemplary embodiments, the second stop condition is related to the difference in beamforming gain between two adjacent iterations.

[0220] Alternatively, in some exemplary embodiments, the second stop condition is related to an instruction to abort the iteration.

[0221] In some exemplary embodiments, the second device further comprises means for receiving information regarding the second stop condition determined by a third device.

[0222] In some exemplary embodiments, the second device receives the first signal by beam sweeping, and the number of beams in the beam sweeping decreases as the number of iterations increases.

[0223] In some exemplary embodiments, the first signal and the second signal are reference signals.

[0224] In some exemplary embodiments, the second device is a network device, the plurality of first devices are terminal devices, or the second device is a terminal device and the plurality of first devices are network devices.

[0225] In some exemplary embodiments, a third device (e.g., the first device 130 in FIG. 1) capable of performing any of the methods 1000 may comprise means for performing each operation of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuit or a software module. The third device may be implemented as or included in the third device 130 in FIG. 1.

[0226] In some exemplary embodiments, the third device comprises means for generating a configuration related to a first signal transmitted by a first device that is a beam alignment initiator or a second signal transmitted by a second device that is a beam alignment coordinator, and means for transmitting the configuration to a network device connected to the third device among the first and second devices.

[0227] In some exemplary embodiments, the configuration indicates transmission resources.

[0228] Alternatively, in some exemplary embodiments, the configuration indicates the timing of transmission.

[0229] As an alternative, in some exemplary embodiments, the configuration indicates the periodicity for transmission.

[0230] Alternatively, in some exemplary embodiments, the configuration indicates an instruction for transmission.

[0231] In some exemplary embodiments, the third device transmits at least one of information regarding a first termination condition used by the first device to determine whether to abort beam alignment to either the first or the second device, which is a network device connected to the third device, or information regarding a second termination condition used by the second device to determine whether to abort beam alignment.

[0232] In some exemplary embodiments, the third device is a central processing unit, the first device is a network device, the second device is a terminal device, or the first device is a terminal device and the second device is a network device.

[0233] FIG. 11 is a simplified block diagram of a device 1100 suitable for implementing an exemplary embodiment of the present disclosure. The device 1100 may be provided to implement a communication device, such as the first device 110, the second device 120, or the third device 130 as shown in FIG. 1. As shown, the device 1100 includes one or more processors 1110, one or more memories 1120 coupled to the processors 1110, and one or more communication modules 1140 coupled to the processors 1110.

[0234] The communication module 1140 is for two-way communication. The communication module 1140 has one or more communication interfaces for facilitating communication with one or more other modules or devices. The communication interface may represent any interface necessary for communication with other network elements. In some exemplary embodiments, the communication module 1140 may include at least one antenna.

[0235] Processor 1110 may be of any type suitable for a local technical network and, by way of non-limiting example, may include one or more of a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 1100 may have multiple processors such as an application-specific integrated circuit chip that is temporally slaved to a clock that synchronizes the main processor.

[0236] Memory 1120 can include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1124, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), optical disk, laser disk, and other magnetic storage and / or optical storage. Examples of volatile memories include, without limitation, random access memory (RAM) 1122 and other volatile memories that do not persist during a power-down duration.

[0237] Computer program 1130 includes computer-executable instructions to be executed by the associated processor 1110. The instructions of program 1130 may include instructions for performing the operations / actions of some exemplary embodiments of the present disclosure. Program 1130 may be stored in a memory, such as ROM 1124. Processor 1110 may execute any suitable actions and processing by loading program 1130 into RAM 1122.

[0238] Exemplary embodiments of the present disclosure may be implemented by program 1130 such that device 1100 can execute any process of the present disclosure discussed with reference to FIGS. 2-10. Exemplary embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0239] In some exemplary embodiments, program 1130 may be tangibly embodied on a computer-readable medium that may be included in device 1100 (such as memory 1120) or other storage devices accessible by device 1100. Device 1100 can load program 1130 from the computer-readable medium into RAM 1122 for execution. In some exemplary embodiments, the computer-readable medium may include any type of non-transitory storage medium such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. As used herein, the term "non-transitory" refers to a limitation on the medium itself (i.e., tangible, as opposed to a signal) as contrasted with a limitation on data storage persistence (e.g., RAM versus ROM).

[0240] FIG. 12 shows an example of a computer-readable medium 1110 that may be in the form of a CD, DVD, or other optical storage disk. Computer-readable medium 1110 has program 1130 stored thereon.

[0241] Generally, the various embodiments of the present disclosure may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. The various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, but the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting example, in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers, or other computing devices or some combination thereof.

[0242] Some exemplary embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer-readable medium, such as a non-transitory computer-readable medium. The computer program product includes computer-executable instructions, such as those included in program modules, that are executed on a device on a target physical processor or virtual processor to perform any of the methods described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The functions of the program modules may be combined or divided among the program modules as desired in various embodiments. The machine-executable instructions for the program modules may be executed within a local or distributed device. In a distributed device, the program modules may be arranged on both a local storage medium and a remote storage medium.

[0243] The program code for performing the methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, and 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 be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0244] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to execute the various processes and operations as described above. Examples of carriers include signals, computer-readable media, etc.

[0245] A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the 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.

[0246] Furthermore, although operations are presented in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in a sequential order, or that all of the shown operations be performed, to achieve desirable results. In some circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above description, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated otherwise, a feature described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated otherwise, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable partial combination.

[0247] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present 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 exemplary forms of implementing the claims.

Claims

1. A first device comprising at least one processor and at least one memory for storing instructions, wherein when the instructions are executed by the at least one processor, the first device is caused to perform at least: transmitting a first signal from the first device to each of a plurality of second devices via a first beam; receiving a second signal transmitted from each of the plurality of second devices via a second beam determined based on the first beam, and updating the first beam at least once by adjusting the first beam based on a measurement result of the received second signal.

2. The first device according to claim 1, wherein the first beam is initially determined as a wide beam.

3. The first device according to claim 1, wherein the first beam is initially determined as a predetermined beam or a beam obtained randomly.

4. The first device according to claim 1, wherein at least one of the first signal or the second signal is periodic.

5. The first device according to claim 1, wherein the step of receiving the second signal includes simultaneously receiving the second signal from the plurality of second devices.

6. The first device according to claim 1, wherein the step of adjusting the first beam includes adjusting the first beam to increase a beamforming gain at the first device with respect to the plurality of second devices.

7. The first device according to claim 1, further causing the first device to execute a step of receiving a configuration generated by a third device and related to at least one of the first signal or the second signal.

8. The configuration indicates at least one of a transmission resource, a timing of transmission, a periodicity for transmission, or an instruction for transmission.

9. The step of updating the first beam includes repeatedly updating the first beam until a first stop condition is satisfied.

10. ​ ​ ​ ​ ​ ​ The first termination condition is the number of iterations, the beamforming gain of the first beam in the first device, the beamforming gain difference between two adjacent iterations, or the first device according to claim 9, characterized in that it is related to at least one of the instructions to terminate the iteration.

11. A second device comprising at least one processor and at least one memory storing instructions, which when executed by at least one of the processors, at least receiving, from each of a plurality of first devices, a first signal transmitted via a first beam determined by each respective first device, and determining a second beam used by the second device for communicating with the plurality of first devices at least once by adjusting the second beam based on the measurement results of the received first signal; and transmitting a second signal to the plurality of first devices via the second beam. The second device is characterized in that it is caused to execute the steps.

12. The second device according to claim 11, characterized in that at least one of the first signal or the second signal is periodic.

13. The second device according to claim 11, characterized in that the step of receiving the first signal includes receiving the first signal from the plurality of first devices simultaneously.

14. The second device according to claim 11, characterized in that the step of adjusting the second beam includes adjusting the second beam to increase the beamforming gain of the second device with respect to the plurality of first devices.

15. The second device according to claim 11, characterized in that the step of adjusting the second beam includes adjusting the second beam to a beam that enables the maximum beamforming gain of the second device with respect to the plurality of first devices.

16. The second device according to claim 11, further characterized in that the second device is caused to execute a step of receiving a configuration related to at least one of the first signal or the second signal generated by a third device.

17. at least one processor and A third device comprising at least one memory for storing instructions, wherein when the instructions are executed by at least one of the processors, at least, generating a configuration related to at least one of a first signal transmitted by a plurality of first devices that are initiators of beam alignment or a second signal transmitted by a plurality of second devices that are beam alignment coordinators; causing the third device to perform transmitting the configuration to one of the first device and the second device, which is a network device connected to the third device. A third device characterized by the above.

18. The configuration is a transmission resource, the timing of transmission, the periodicity for transmission, or indicating at least one of instructions for transmission. The third device according to claim 17, characterized in that.

19. Causing the third device to further perform transmitting to one of the first device and the second device, which is a network device connected to the third device, at least one of information regarding a first termination condition used by the first device to determine whether to terminate beam alignment or information regarding a second termination condition used by the second device to determine whether to terminate beam alignment. The third device according to claim 17, characterized in that.

20. The third device is a central processing unit, The third device according to claim 17, characterized in that the first device is a network device and the second device is a terminal device, or the first device is a terminal device and the second device is a network device.

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