Access procedures for cell-free MIMO

Abstract

This disclosure relates to exemplary embodiments of methods, apparatuses, devices, and computer-readable storage media for cell-free multiple-input multiple-output (MIMO) access procedures. In an exemplary embodiment, a terminal device transmits an access request to a first group of uplink access network devices. The access request includes a list of identifiers of candidate downlink access network devices. The terminal device then receives an access response from the first group of downlink access network devices.

Description

Technical Field

[0001] The exemplary embodiments of this disclosure generally relate to the field of communications, and more particularly to methods, apparatuses, devices, and computer-readable storage media for cell-free multiple-input multiple-output (MIMO) access procedures. Background Technology

[0002] Cell-free multiple-input multiple-output (MIMO) is considered a key technology in sixth-generation (6G) networks, enabling high system capacity in both sub-6G and millimeter-wave (mmW) bands. In a 6G cell-free MIMO network architecture, there are at least two types of network devices: access points (APs) and a central processing unit (CPU). Two key features of cell-free MIMO are multiple APs connected to the CPU, and multiple APs serving user equipment (UEs) in both uplink (UL) and downlink (DL) communications to achieve higher system performance.

[0003] Due to the differences in network architecture and characteristics between 6G and 5G / 4G, some procedures traditionally defined in 5G / 4G are no longer applicable in 6G. To date, there has been no discussion regarding access procedures for supporting cell-free MIMO transmission in 6G. Summary of the Invention

[0004] In general, exemplary embodiments of this disclosure provide methods, apparatus, devices, and computer-readable storage media for cell-free multiple-input multiple-output (MIMO) access procedures.

[0005] In a first aspect, a method is provided at a terminal device. In this method, the terminal device transmits an access request to a first group of uplink access network devices. The access request includes a list of identifiers of candidate downlink access network devices. The terminal device then receives an access response from the first group of downlink access network devices.

[0006] In a second aspect, a method is provided at a central network device. In this method, the central network device receives an access request from a terminal device via a third group of uplink access network devices, containing a list of identifiers of candidate downlink access network devices. Then, the central network device transmits an access response to the terminal device via a first group of downlink access network devices.

[0007] In a third aspect, a method is provided at a first uplink access network device. In this method, the first uplink access network device receives an access request from a terminal device. The access request includes a list of identifiers of candidate downlink access network devices. The first uplink access network device forwards the access request to a central network device.

[0008] In a fourth aspect, a method is provided at a second uplink access network device. In this method, the second uplink access network device receives a connection establishment request from a terminal device. The second uplink access network device forwards the connection establishment request to a central network device. The second uplink access network device transmits a receive power indication of the connection establishment request to the central network device.

[0009] In a fifth aspect, an apparatus is provided, comprising at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured, together with the at least one processor, to cause the apparatus to perform a method according to any one of the first to fourth aspects.

[0010] In a fifth aspect, an apparatus is provided that includes components for performing a method according to any one of the first to fourth aspects.

[0011] In a sixth aspect, a computer-readable storage medium is provided, comprising program instructions stored thereon. When executed by a processor of a device, the instructions cause the device to perform a method according to any one of the first to fourth aspects.

[0012] It should be understood that the overview section is not intended to identify key or essential features of the exemplary embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0013] Some exemplary embodiments will now be described with reference to the accompanying drawings, in which:

[0014] Figure 1 A general network architecture for 6G cell-free MIMO transmission is shown;

[0015] Figure 2 An example environment in which example embodiments of this disclosure may be implemented is shown;

[0016] Figure 3 The signaling flow between a terminal device, a first UL access network device, a DL access network device, and a central network device according to some example embodiments of the present disclosure is illustrated.

[0017] Figure 4 The signaling flow between a terminal device, a second UL access network device, a DL access network device, and a central network device is illustrated according to some other example embodiments of this disclosure;

[0018] Figure 5The signaling flow of exchanged access requests and access responses according to some example embodiments of this disclosure is illustrated;

[0019] Figure 6 The signaling flow of a connection establishment request and a connection establishment response according to some example embodiments of the present disclosure is illustrated;

[0020] Figure 7 The signaling flow for exchanging messages 1 and 2 according to some example embodiments of the present disclosure is illustrated;

[0021] Figure 8 The signaling flow for exchanging messages 3 and 4 according to some example embodiments of the present disclosure is illustrated;

[0022] Figure 9 A flowchart is shown illustrating an example method at a terminal device according to some example embodiments of the present disclosure;

[0023] Figure 10 A flowchart is shown illustrating an example method at a central network device according to some example embodiments of the present disclosure;

[0024] Figure 11 A flowchart is shown showing an example method at a first UL access network device according to some example embodiments of the present disclosure;

[0025] Figure 12 A flowchart illustrating an example method at a second UL access network device according to some example embodiments of this disclosure is shown; and

[0026] Figure 13 A simplified block diagram of an apparatus suitable for implementing an example embodiment of the present disclosure is shown.

[0027] Throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0028] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these exemplary embodiments are described merely for illustration and to help those skilled in the art understand and implement this disclosure, and do not imply any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various other ways besides those described below.

[0029] 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.

[0030] As used herein, the terms "terminal device" or "user equipment" (UE) refer to any terminal device capable of wirelessly communicating with each other or with a base station. Communication may involve transmitting and / or receiving wireless signals using electromagnetic signals, radio waves, infrared signals, and / or other types of signals suitable for transmitting information over the air. In some example embodiments, the UE may be configured to transmit and / or receive information without direct human-machine interaction. For example, when triggered by an internal or external event, or in response to a request from the network side, the UE may transmit information to the base station according to a predetermined schedule.

[0031] Examples of UEs include, but are not limited to, smartphones, wireless-enabled tablets, laptop embedded devices (LEEs), laptop-mounted devices (LMEs), wireless client devices (CPEs), sensors, metering devices, personal wearable devices such as watches, and / or vehicles capable of communication. For the purposes of discussion, some exemplary embodiments will be described with reference to UEs as examples of terminal devices, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of this disclosure.

[0032] As used herein, the term "network device" refers to a device on the network side that provides services to terminal devices in a communication network. As used herein, the term "access network device" refers to a network device through which terminal devices can access the network. As used herein, the term "uplink access network device" refers to a network device serving terminal devices in UL communication, and the term "downlink access network device" refers to a network device serving terminal devices in DL communication. As used herein, the term "central network device" refers to a device on the network side that controls and schedules uplink and downlink access network devices to serve terminal devices. For the purposes of discussion, some exemplary embodiments will be described with reference to the UL / DL access point (AP) as an example of uplink and downlink access network devices and to the central processing unit (CPU) as an example of a central network device.

[0033] As used herein, the term "circuit system" may refer to one or more, or all of the following:

[0034] (a) Pure hardware circuit implementation (such as implementation using only analog and / or digital circuit systems), and

[0035] (b) A combination of hardware circuitry and software, such as (if applicable):

[0036] (i) A combination of (multiple) analog and / or digital hardware circuits and software / firmware, and

[0037] (ii) Any part of a hardware processor(s) having software (including (multiple) digital signal processors), software, and (multiple) memories, which work together to cause a device (such as a mobile phone or server) to perform various functions, and

[0038] (c) Multiple hardware circuits and / or multiple processors, such as multiple microprocessors or a portion thereof, that require software (e.g., firmware).

[0039] The software can be used to perform operations, but it may not exist when no operation is needed.

[0040] The definition of "circuit system" applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term "circuit system" also covers implementations of only hardware circuitry or processors (or processors in general) or portions thereof and their accompanying software and / or firmware. For instance, if applicable to a particular claim element, the term "circuit system" also covers baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular base stations, or other computing or base stations.

[0041] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context explicitly indicates otherwise. The term “comprising” and its variations should be understood as open terms meaning “including, but not limited to.” The term “based on” should be understood as “at least partially based on.” The terms “an embodiment” and “embodiment” should be understood as “at least one embodiment.” The term “another embodiment” should be understood as “at least one other embodiment.” Other definitions (explicit and implicit) may be included below.

[0042] As used herein, the terms “first,” “second,” etc., may be used to describe various elements, and these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0043] Figure 1A general network architecture 100 for 6G cellless MIMO transmission is illustrated. As shown, multiple APs 105 are connected to CPU 110 and serve UE 115 in both the uplink (UL) and downlink (DL) to facilitate UE 115's UL and DL transmissions for higher system performance. The functional division between APs 105 and CPU 110 is still under discussion, particularly at Layer 1 (L1) or the physical layer. The selection of APs 105 serving UE 110 is also still under discussion.

[0044] Obviously, as Figure 1 The network architecture shown for 6G cellless MIMO differs from traditional 5G and 4G networks. This will mean that many traditional processes and signaling flows used in the 5G and 4G phases cannot be used in the 6G phase to achieve cellless access and transmission.

[0045] The inventors noted that access procedures and mobility processing are critical issues in achieving cell-free MIMO transmission. In traditional 5G / 4G, a four-step access procedure is used to achieve UL synchronization (SYN) with the network and establish a connection between the UE and the base station (e.g., gNB). This four-step access procedure involves the transmission of four messages over the air interface between the UE and the base station. For example, the UE first sends message 1 containing a random access request to the base station, allowing the base station to calculate the timing advance (TA) value. The base station then sends message 2 to the UE containing the TA value and other configuration information (including scheduling information for message 3). The UE then sends message 3 containing connection information to the base station. The base station sends message 4 to the UE to confirm the connection and indicate relevant configurations. However, due to different network architectures and characteristics, this four-step access procedure used in traditional 5G / 4G systems cannot be applied to 6G to achieve cell-free MIMO transmission.

[0046] The four-step process in 5G / 4G involves only one UE and one gNB. Therefore, the UE only needs to perform a ULSYN with one gNB to ensure that subsequent UL / DL communication between the UE and the gNB can occur immediately after the access procedure. However, for 6G cell-free MIMO, the communication link involves three types of nodes or devices, and more than one AP will be selected for the UE's UL / DL transmission. Therefore, the traditional four-step process between a UE and one gNB is not suitable for 6G cell-free MIMO scenarios. An access procedure needs to be designed in this new network architecture, and appropriate access points need to be selected to facilitate the UE's UL / DL transmission.

[0047] This disclosure provides an example embodiment of an access scheme in a network architecture that includes three types of devices: terminal devices (such as UEs), UL / DL access network devices (such as UL / DL APs), and central network devices (such as CPUs). Through this access scheme, the terminal device transmits an access request (such as message 1) to the network containing a list of identifiers of candidate downlink access network devices for the final selection and confirmation of DL access network devices. The access request is received by one or more UL access network devices (referred to as the first group of UL access network devices). The terminal device then receives an access response (such as message 2) from one or more downlink access network devices (referred to as the first group of DL access network devices).

[0048] In this way, the network side can make the final decision on selecting multiple DL access network devices with the assistance of terminal equipment. Accordingly, these DL access network devices will be activated immediately after the access process, thereby improving transmission efficiency and reducing system overhead.

[0049] Figure 2 An example environment 200 in which example embodiments of the present disclosure may be implemented is shown.

[0050] Environment 200, which may be part of a communication network, includes terminal device 210, central network device 220, and multiple UL access network devices 230-1, 230-2, ..., 230-N and multiple DL access network devices 240-1, 240-2, ..., 240-M, where N and M represent positive integers greater than 2. UL access network devices 230-1, ..., 230-N and DL access network devices 240-2, ..., 240-M can be scheduled by central network device 220 to serve terminal device 210 in UL / DL communication. For the purposes of discussion, the UL and DL access network devices will be collectively referred to as UL access network device 230 and DL access network device 240, or individually.

[0051] It should be understood that the UL and DL access network devices are shown separately for illustrative purposes only and do not imply any limitation on the scope of this disclosure. In some example embodiments, the UL or DL ​​access network device may have both UL and DL communication capabilities, and thus be able to serve terminal device 210 in both UL and DL communication.

[0052] It should also be understood that the illustration of a terminal device, a central network device, and multiple UL / DL access network devices in Environment 200 is for illustrative purposes only and does not imply any limitation on the scope of this disclosure. In some example embodiments, Environment 200 may include more terminal devices, which may be served by more UL / DL access network devices scheduled by more central network devices.

[0053] Communications in Environment 200 may follow any suitable communication standards or protocols that are already in use or will be developed in the future, such as Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), LTE-Advanced (LTE-A), 5G New Radio (NR), Wi-Fi, and Global Microwave Access Interoperability (WiMAX) standards, and may employ any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), Bluetooth, ZigBee and Machine-Type Communications (MTC), Enhanced Mobile Broadband (eMBB), Massive Machine-Type Communications (mMTC), Ultra-Reliable Low-Latency Communications (URLLC), Carrier Aggregation (CA), Dual Connectivity (DC), and New Radio Unlicensed (NR-U) technologies.

[0054] In environment 200, when terminal device 210 wants to access the network, terminal device 210 transmits an access request to a first group of UL access network devices 230, which includes a list of identifiers of candidate DL access network devices. The first group of UL access network devices 230 then forwards the access request to the central network device 220. In different example embodiments, the first group of UL access network devices may or may not be identified by terminal device 210, as will be detailed in the following paragraphs.

[0055] From the candidate DL access network devices identified by terminal device 210, central network device 220 can determine one or more serving DL access network devices 230 during the access process. Furthermore, the serving DL access network device can be activated immediately after the access process. Therefore, communication efficiency can be improved, thereby enhancing system performance.

[0056] Then, terminal device 210 receives an access response from the first group of DL access network devices 240. The first group of DL access network devices 240 may or may not be selected from the candidate DL access network devices identified by terminal device 210 in the access request, as will be detailed in the following paragraphs.

[0057] Figure 3 Signaling flow 300 between terminal device 210, UL access network device 230-1, DL access network device 240-1 and central network device 220 according to some example embodiments of the present disclosure is illustrated.

[0058] like Figure 3As shown, terminal device 210 transmits (305) an access request to a first group of UL access network devices 230, including UL access network device 230-1 (referred to as first UL device 230-1). The access request contains a list of identifiers of candidate UL access network devices. Additionally, the access request may contain access resource indications, such as preamble information, radio resource indications, and / or other access-related resource indications currently used or to be used in the future during the access process. The access request may be carried in message 1 or in any other suitable message that may be used during the access process.

[0059] Candidate DL access network devices can be determined by terminal device 210 based on the received power of signals from candidate downlink access network devices. In some example embodiments, the identifiers of candidate DL access network devices can be sorted in a list based on their corresponding received power. For example, the identifiers of candidate DL access network devices can be arranged in descending or ascending order of received power. The identifiers of candidate DL access network devices can also be sorted according to other predefined principles. The order of the identifiers of candidate DL access network devices can be used by the network to distinguish access requests from different terminal devices. This is because the probability of access requests from different terminal devices having the same list of candidate DL access network devices and the same order information is very low.

[0060] As described above, terminal device 210 may or may not identify the first group of UL access network devices 230. In some example embodiments, terminal device 210 may, for example, use common access resources to transmit access requests. For example, central network device 220 may configure the same access-related information to UL access network devices within the access cluster. When terminal device 210 transmits an access request to the network via the air interface using access-related information, all UL access network devices in the access cluster are likely to successfully decode the access request, thereby forming the first group of UL access network devices. It is possible for multiple UL access network devices to successfully decode the access request simultaneously. Therefore, spatial diversity can be utilized to improve the probability of successful reception of access requests.

[0061] In some other example embodiments, terminal device 210 may use access resources scheduled or allocated to one or more specific UL access network devices 230 to transmit access requests, for example, with the receiver designated by central network device 220. For instance, terminal device 210 may use access resources dedicated to a first UL access network device 230-1 to transmit access requests. In this example, the first group of UL access network devices may consist only of the first UL access network device 230-1.

[0062] In some example embodiments, to increase the probability of successful transmission of access requests, terminal device 210 may transmit access requests one after another to the first UL access network device 230-1 and other UL access network devices in the first group of network devices. These UL access network devices may be assigned to the same access resources or different access resources.

[0063] In this example, such as Figure 3 As shown, the first UL access network device 230-1 receives (310) an access request and then forwards (315) the access request to the central network device 220. For illustrative purposes only, Figure 3 Only the first UL access network device 230-1 is shown in the diagram. In embodiments where the first group of UL access network devices includes multiple UL access network devices, one or more other UL access network devices in the first group of UL access network devices may have the opportunity to receive access requests and forward them to the central network device 220.

[0064] Therefore, the central network device 220 receives (320) an access request containing a list of identifiers of candidate DL access network devices. In an example embodiment where the access request includes an access resource indication and / or the identifiers of the candidate DL access network devices are ordered, the central network device 220 can identify that the access request was transmitted by the terminal device 210. Therefore, the network device 220 can distinguish between access requests transmitted by different terminal devices.

[0065] Based on the candidate DL access network devices identified by terminal device 210, central network device 220 can determine one or more serving DL network devices to serve terminal device 210, thereby improving communication efficiency. To determine the DL access network devices, central network device 220 may also consider other information, such as the load of individual DL access network devices and the number of terminal devices being served. The determined serving DL access network devices may include at least one primary DL access network device and zero or more other serving DL access network devices.

[0066] In some example embodiments, after the first UL access network device 230-1 successfully decodes the access request, the first UL access network device 230-1 can calculate the relevant timing advance (TA) value and forward the access request along with the calculated TA value to the central network device 220. Alternatively or additionally, the first UL access network device 230-1 can also report the received power indication of the access request to the central network device 220, enabling the central network device 220 to determine one or more serving UL access network devices for the terminal device 210 to further improve communication efficiency.

[0067] For example, when multiple UL access network devices in the first group of UL access network devices forward access requests and report corresponding receive power indications, the central network device 220 can select a UL access network device with a receive power higher than a configured threshold as the serving UL access network device for the terminal device 210. Similar to the selection of serving DL access network devices, the selection of serving UL access network devices can also consider load conditions and the number of terminal devices being served. In some example embodiments, the UL access network device with the highest receive power among the serving UL access network devices can be selected as the primary UL access network device.

[0068] Upon receiving an access request, the central network device 220 transmits an access response (325) to the first group of DL access network devices 240, including DL access network devices 240-1. As an example, the access response may be carried in message 2. For illustrative purposes only. Figure 3 Only DL access network device 240-1 is shown in the diagram. The first group of DL access network devices 240 may additionally include one or more other DL access network devices to utilize spatial diversity to improve the probability of successful transmission. The first group of DL access network devices 240 may be selected from serving DL access network devices determined by the central network device 220 based on a list of identifiers of candidate DL access network devices in the access request. For example, the central network device 220 may transmit the access response to all determined serving DL access network devices or only to the serving DL access network device with the highest received power. It is possible for the central network device 220 to select other DL access network devices besides the determined serving DL access network devices.

[0069] In some example embodiments, the access response may include a list of identifiers of serving UL access network devices and / or a list of identifiers of serving DL access network devices. Therefore, terminal device 210 can communicate with these serving UL and / or DL ​​access network devices immediately after the access process to improve communication efficiency. Alternatively or additionally, central network device 220 may assign an identifier (such as a UE ID) to terminal device 210 for use in subsequent communications and include the identifier of terminal device 210 in the access response. Alternatively or additionally, the access response may include TA information associated with the identified serving UL access network devices for use by terminal device 210 in subsequent communications.

[0070] In this example, such as Figure 3As shown, DL access network device 240-1 receives (330) an access response and then forwards (335) the access response to terminal device 210. Therefore, terminal device 210 receives (340) an access response from DL access network device 240-1. If more than one DL access network device 240 transmits an access response to terminal device 210, terminal device 210 can automatically combine the received power of the access responses from these DL access network devices 240, thereby utilizing spatial diversity to improve the success probability of receiving the access response.

[0071] When terminal device 210 continuously transmits access requests to multiple UL access network devices in the first group of UL access network devices 230, terminal device 210 can continuously detect multiple versions of access responses from the first group of DL access network devices 240 and combine these versions of the access responses to improve decoding performance. For example, terminal device 210 can treat each access response from an individual DL access network device as a different HARQ retransmission of the same source message, even though these transmissions may occur simultaneously. Terminal device 210 can process each access response independently, for example, down to the soft bit level. Then, terminal device 210 can perform soft bit-level combination of all versions of the access response to finally decode the access response. At this point, terminal device 210 can access the network.

[0072] In some example embodiments, in addition to the exchange of access requests and access responses described above, the access process may also involve the exchange of connection establishment requests and connection establishment responses between the terminal device 210 and the network. Reference will be made below. Figure 4 Examples of implementations in this regard are discussed.

[0073] Figure 4 Signaling flow 400 between terminal device 210, UL access network device 230-2, DL access network device 240-2 and central network device 220 according to some example embodiments of the present disclosure is illustrated.

[0074] like Figure 4 As shown, terminal device 210 transmits a (405) connection establishment request to a second group of UL access network devices 230, including UL access network device 230-2 (referred to as second UL device 230-2). For example, the connection establishment request may be carried in message 3. The connection establishment request may contain connection-related information.

[0075] Connection establishment requests can be transmitted based on scheduling by the central network device 220. For example, upon receiving an access request, the central network device 220 can schedule uplink resources for transmission of the connection establishment request to, for example, a selected primary UL access network device or other serving UL APs. In some example embodiments, if the terminal device 210 sends an access request to only one UL access network device, the central network device 220 can select a temporary primary UL access network device to receive the connection establishment request. The central network device 220 can also notify all other serving UL access network devices to detect upcoming connection establishment requests, so that the final primary UL access network device and other potential serving UL access network devices can be used to facilitate UL communication of the terminal device 210. In this case, the second group of UL access network devices 230 may include scheduled serving UL access network devices, including the primary UL access network device and other potential UL access network devices.

[0076] The central network device 220 can include scheduling information for the connection establishment request in the access response. Therefore, upon receiving the access response, the terminal device 210 can use the scheduled resources to transmit the connection establishment request to the scheduled UL access network device indicated by the access response.

[0077] In this example, such as Figure 4 As shown, the second UL access network device 230-2 receives (410) a connection establishment request and forwards (415) a connection establishment request to the central network device 220. The central network device 220 receives (420) a connection establishment request, for example, from the second UL access network device 230-2 and one or more other UL access network devices in the second group of UL access network devices. Upon receiving the connection establishment request, the central network device 220 may perform connection-related procedures.

[0078] In some example embodiments, the selection of serving UL access network devices can be performed by the central network device 220 from a second group of UL access network devices. In these embodiments, the second group of UL access network devices can measure the received power of a connection request from the terminal device 210 and report the received power indication to the central network device 220. In some example embodiments, the central network device 220 can instruct these UL access network devices to report the received power indication. Upon receiving such an instruction, the second group of UL access network devices can transmit the received power indication of the connection request.

[0079] The second group of UL access network devices can separately calculate the corresponding TA information and report it to the central network device 220. Therefore, the central network device 220 can obtain the measured power and TA information, and based on this information, ultimately select the primary UL access network device and other potential service UL access network devices.

[0080] Then, the central network device 220 transmits a connection establishment response (425) to a second group of DL access network devices 240, including DL access network device 240-2 (referred to as the second DL access network device 240-2). For example, the connection establishment response may be carried in message 4. If the central network device 220 selects a serving UL access network device from the second group of UL access network devices, the central network device 220 may include a list of identifiers of the serving UL access network device and the corresponding TA information in the connection establishment response. In some example embodiments, the central network device 220 may include the list of identifiers of the serving DL access network device in the connection establishment response instead of the access response.

[0081] like Figure 4 As shown, the second DL access network device 240-2 receives (430) a connection establishment response and forwards (435) a connection establishment response to the terminal device 210. Therefore, the terminal device 210 receives (440) a connection establishment response from the second DL access network device 240-2 and one or more other DL access network devices in the second group of DL access network devices. For example, in an embodiment where the access response indicates the primary DL access network device, the terminal device 210 may detect the control channel of the primary DL access network device to receive the connection establishment response. The access process then completes.

[0082] It should be understood, as referenced above Figure 3 Some signal processing operations and actions described in signaling flow 300 are also applicable to signaling flow 400 and have similar effects. For simplicity, details will be omitted.

[0083] The following examples will use UE, UL / DL AP, and CPU as terminal device 210, UL / DL access network devices 230 and 240, and central network device 220 for reference. Figures 5-8 Three specific example implementations are discussed.

[0084] First Embodiment

[0085] In the first embodiment, the UE sends Message 1, carrying an access request, only once on the air interface. Message 1 includes a list of candidate DL AP IDs for final decision-making by the CPU. On the network side, multiple UL APs will automatically examine Message 1 from the UE and report Message 1 to the CPU based on the decoding results. The participation of multiple UL APs can utilize UL receive spatial diversity to improve the probability of successful transmission of Message 1.

[0086] Figure 5 Signaling flow 500 for switching access requests and access responses according to some example embodiments of this disclosure is shown.

[0087] like Figure 5 As shown, multiple APs 505-1, 505-2, ..., 505-n (where n represents a positive integer greater than 2) belong to access cluster 507. These APs 505-1, 505-2, ..., 505-n have the capability to communicate with UE 510 via UL and DL. To allow the participation of multiple APs 505-1, 505-2, ..., 505-n, CPU 515 can configure the same access-related information to all APs 505-1, 505-2, ..., 505-n within the same access cluster. The access-related information may include random preamble information, radio resources for signaling transmission of message 1, and a corresponding message 2 containing the access response. All UL APs within the same access cluster will attempt to detect potential UL transmission of message 1 on the configured resources.

[0088] like Figure 5 As shown, at 520, CPU 515 executes DL SYN with multiple APs 505-1, 505-2, ..., 505-n to allocate the same access resources, such as preamble, frequency domain, and time domain resources. Before the access procedure begins, at 525, UE 510 implements DL SYN with potential APs 505-1, 505-2, ..., 505-n and obtains access-related configurations, enabling the UE to know when and where to send message 1. Furthermore, at 525, UE 510 can select a potential serving DL AP as a candidate DL AP.

[0089] After the preparation phase described above, UE 510 can begin the access procedure. Figure 5 As shown, in 530, UE510 specifies message 1, which contains a list of candidate DL AP IDs, access resource indications, and other access-related information. These AP IDs can be sorted according to predefined principles, such as descending or ascending order of received power.

[0090] Access resource indication and DL AP ID list can be used to distinguish access requests from different UEs. In other words, these two types of information are used to resolve access conflicts that occur during random access. This is because the probability of two different UEs selecting the same access resource and indicating the same DL AP list in the same order in message 1 is very low. As described below, on the network side, the CPU 515 will use these two types of information to identify whether message 1 forwarded by multiple APs comes from the same or different UEs and take corresponding actions.

[0091] In step 535, UE 510 sends message 1 to the network once via the air interface. Multiple APs within the same access cluster attempt to receive and decode message 1 and forward the access request in message 1 to CPU 515. As mentioned above, CPU 515 configures the same access-related resources for all UL APs within the same access cluster. Therefore, all these related UL APs will attempt to detect potential transmission of message 1 based on this configuration. In this way, although UE 510 sends message 1 only once via the air interface, multiple APs may be able to successfully decode message 1 simultaneously. Thus, spatial diversity can be utilized to improve the success probability of message 1 reception, which can realize the benefits of cell-free transmission during the access phase.

[0092] In this example, at 540, AP 505-1 successfully decodes message 1, and at 545, AP 505-2 successfully decodes message 1. At 550, APs 505-1 and 502-2 forward message 1 to CPU 515 to forward the list of candidate DL AP IDs and access resource indications. In this example, at 550, APs 505-1 and 502-2 also report the receive power indication of their message 1 to CPU 515, enabling CPU 515 to determine the list of serving UL AP IDs, as discussed in the following paragraphs. APs 505-1 and 502-2 can calculate the relevant TA value and forward message 1 along with the calculated TA value to CPU 515.

[0093] In 555, CPU 515 identifies that message 1 from the AP is transmitted by the same UE, assigns a UE ID to UE 510, determines the primary UL / DL AP, determines other serving UL / DL APs, and schedules message 3 on the primary UL AP and other potential serving UL APs. For example, CPU 515 can distinguish different access requests from different UEs based on the Access Resource Indication and the list of candidate DL AP IDs in message 1. As an example, for message 1 with the same Access Resource Indication and the same list of candidate DL APs, message 1 is very likely from the same UE.

[0094] CPU 515 can determine the primary DL AP and other potential serving DL APs based on the candidate DL AP list provided by UE 510, as well as other information such as the load information of the corresponding AP and the serving UE information. The finally confirmed serving DL APs may include at least one primary DL AP and zero or more other serving DL APs.

[0095] CPU 515 can select and confirm the serving UL AP based on input from the UL AP that successfully decoded and forwarded message 1, as well as other information about the corresponding UL AP, such as load information and the number of UEs served. As described above, each UL AP with successful Layer 1 (L1) decoding will report the detection power information of its message 1. CPU 515 can select the serving UL AP, for example, the UL AP with a received power higher than a configured threshold. The UL AP with the highest UL received power can be selected as the primary UL AP, while other UL APs can be confirmed as serving UL APs.

[0096] Subsequently, CPU 515 can transmit scheduling resources for message 3, for example, on the newly selected primary UL AP or other serving UL AP. Scheduling information can be included in message 2 so that UE 510 can take corresponding actions.

[0097] In the 555, CPU 515 also specifies message 2, which contains the UE ID, a list of primary UL / DL AP and serving UL / DL AP IDs, a list of TAs for each serving UL AP, and the resources scheduled for message 3. For example, CPU 515 can generate the content of message 2 and forward it to all selected DL serving APs for message 2 transmission, and inform these DL APs on which radio resources to transmit message 2.

[0098] In this example, at 560, CPU 515 transmits message 2 to APs 505-1 and 505-2. At 565, upon receiving message 2, APs 505-1 and 505-2 forward message 2 down to UE 510 to utilize spatial diversity to improve the probability of successful transmission of message 2. These transmissions can use the same radio resources instructed by the CPU.

[0099] This transmission of message 2 is completely transparent to UE 510. On the UE side, the power of all DL APs will be summed to obtain power combining gain, thereby improving the probability of successful decoding of message 2. After this, UE 510 will know its UEID, the list of UL / DL serving APs, and the UL APs and corresponding resources used for the transmission of message 3 carrying the connection establishment request. At this point, UE 510 and CPU 515 are synchronized regarding which AP lists will be used for UL and DL communication, enabling cellless UL / DL transmission to be executed immediately after the access procedure is completed.

[0100] Figure 6 Signaling flow 600 for exchange connection establishment request and connection establishment response according to some example embodiments of the present disclosure is shown.

[0101] In this example, such as Figure 6 As shown, at 605, APs 505-1, 505-2, ..., 505-n all transmit message 2 to UE 510. At 610, UE 510 automatically combines message 2 from multiple APs 505-1, 505-2, ..., 505-n and decodes message 2. After decoding message 2, UE 510 obtains the UE ID, UL / DL AP list, TA list, and scheduling information for message 3.

[0102] At 615, UE 510 transmits message 3 to AP 505-2, as indicated by message 2. Message 3 may include connection-related information. After the transmission of message 3, at 620, UE 510 begins checking the control channel on the primary DL AP (e.g., AP 505-1) to receive message 4, which carries a connection establishment response.

[0103] At 625, AP 505-2 decodes message 3 and forwards it to CPU 515 for connection-related configuration. At 630, CPU 515 receives message 3, performs confirmation of the serving UL / DL AP, and generates message 4. At 635, CPU 515 sends message 4 to AP 505-1, which is the primary DL AP. For example, after CPU 515 completes the connection-related process, CPU 515, for example, schedules the transmission of message 4 on the primary DL AP and forwards message 4 to the corresponding serving DL AP for transmission.

[0104] At 640, AP 505-1 transmits message 4 to UE 510 to confirm the connection establishment. At 645, UE 510 receives message 4 to complete the access procedure. At this point, UE 510 and the network are synchronized on all assigned serving UL / DL APs, and the access procedure ends.

[0105] Second Embodiment

[0106] In the second embodiment, in addition to access-related information, the UE sends Message 1 one after another to multiple UL APs to report a list of potential candidate DL APs. Here, the list of DL candidate APs can be represented by a matrix to distinguish access requests from the same or different UEs. After the transmission of Message 1, the UE can attempt to check the DL transmission of Message 2 on potential DL APs with resources linked to the corresponding transmission of Message 1.

[0107] On the network side, similar to the first embodiment, multiple UL APs can independently attempt to decode message 1 and report the decoding results along with their UL received power information to the CPU. After obtaining forwarding information from one or more UL APs, the CPU can decide to select a primary DL AP and other serving DL APs from the candidate DL APs reported by the UE. Furthermore, the CPU can determine a list of primary UL APs and other potential serving UL APs among those UL APs that reported receiving message 1. Another important function of the CPU is to schedule the transmission of message 3 on UL APs in the potential serving UL AP list using the same or different radio resources. The CPU can include information in message 2 and forward it to those DL APs on which the UE is waiting for DL ​​transmission of message 2.

[0108] The reception process for message 2 also differs from the first embodiment. In the first embodiment, message 2 is transmitted from different DL APs on the same radio resources. The UE only needs to combine the received power from the DL APs to improve the decoding performance of message 2. In the second embodiment, however, message 2 is transmitted from DL APs that potentially have different radio resources. The UE can treat message 2 from individual DL APs as different HARQ retransmissions of the same source message, even though these transmissions occur simultaneously. Therefore, the UE can process the transmissions from each DL AP independently down to the soft-bit level. Then, the UE can perform soft-bit-level combination of message 2 from all DL APs to finally decode message 2 for the next step.

[0109] The transmission of message 3 is no different from the first embodiment, based on the indication in message 2. Then, assuming the CPU can schedule message 4 at least on the selected primary DL AP, the UE can attempt to check message 4 on the primary DL AP. On the network side, the corresponding UL AP decodes message 3 and forwards it to the CPU for final processing. Finally, the CPU configures the connection-related procedures and schedules message 4 at least on the primary DL AP. Message 4 can also be scheduled on other serving DL APs, but the same radio resources as the primary DL AP can be used. The aim is to implement power combining gain for message 4 reception on the UE side to improve the success probability.

[0110] In summary, the differences between the second embodiment and the first embodiment are as follows: Regarding the UL transmission of message 1, message 1 is transmitted one after another to multiple UL APs using the same or different radio resources. Regarding the DL transmission of message 2, message 2 is transmitted from multiple DL APs using the same or different radio resources respectively. The UE knows the radio resources used to receive each message 2. In the first embodiment, however, the UE may not know which DL APs can transmit message 2 from, but the UE only knows which radio resource can be used to send message 2. Therefore, the UE only needs to check the corresponding radio resource and combine all the received power on that resource to process message 2.

[0111] For DL ​​reception of message 2, the UE can process each DL message 2 independently down to the soft bit level, and then combine each message 2 to obtain a combination gain, similar to the HARQ combination process. However, in the first embodiment, as described above, the UE can achieve power combination gain, but cannot achieve a gain similar to HARQ combination.

[0112] Third Embodiment

[0113] In both the first and second embodiments, regardless of how many times message 1 is transmitted over the air, multiple UL APs can attempt to receive message 1 and report the results to the CPU. Multiple DL APs can be scheduled to send message 2 via the air interface. After message 2 is received on the UE side, the UE and CPU align on a selected set of serving UL / DL APs, including a primary UL / DL AP and zero or more other serving UL / DL APs.

[0114] The third embodiment provides another possibility for selecting a serving UL AP and a serving DL AP at different stages of the access procedure. In the third embodiment, the UE first selects a temporary primary DL AP and other potential serving DL APs, and includes a list of candidate DL AP IDs in message 1, similar to the first and second embodiments. Message 1 is sent to a UL AP, which may be linked to the temporarily selected primary DL AP. After the transmission of message 1, the UE begins waiting for message 2 on the AP using the resources linked to the access information of message 1.

[0115] Only one UL AP can receive message 1 and report its contents to the CPU. The CPU can then determine the primary DL AP and other potential serving DL APs based on the candidate AP ID list from the UE side. For UL transmissions, the CPU can only select a temporary primary UL AP at this stage, which is the UL AP that received message 1. Next, the CPU can schedule the transmission of message 2 on the DL AP using resources linked to the previous access information in message 1. Furthermore, the CPU can schedule the transmission of message 3 on the newly temporarily selected UL AP. Another important action on the CPU side is to provide transmission resources for message 3 to all other UL APs within the access cluster 507. This is to help the CPU select the final serving UL AP after message 3 is received.

[0116] Based on the above principle, message 2 is transmitted only once over the air on the DL AP linked to the transmission of message 1. On the UE side, after receiving message 2, the UE knows the finally selected primary DL AP and other serving DL APs. Based on message 2, the UE only sends message 3 once to the corresponding UL AP. Afterwards, the UE can attempt to check the control channel of the selected primary DL AP.

[0117] Next, on the network side, the CPU has notified multiple UL APs of the resources to be used in message 3. Besides the temporary primary UL AP, multiple UL APs can also measure the received power of message 3, calculate the corresponding TA information, and report this information to the CPU accordingly. The temporary UL AP can decode message 3 and forward its content to the CPU for further processing. On the CPU side, it can obtain the measured power information and TA of potential UL APs, as well as the content of message 3. Based on this information, the CPU can ultimately select the primary UL AP and other potential serving UL APs. Then, the CPU can include this information and the corresponding TA information in message 4 and notify the UE later.

[0118] Compared to the first and second embodiments, in the third embodiment, messages 1, 2, and 3 can be transmitted only once over the air. Only one UL or DL ​​AP can be responsible for receiving or transmitting messages 1 or 2 respectively. Spatial diversity and combination gain are not implemented for processing these two messages. Multiple UL APs may be involved only for receiving message 3. Therefore, the primary DL AP and the serving DL AP can be acknowledged after processing message 2. Similarly, the primary DL AP and the serving UL AP can be acknowledged after processing message 3.

[0119] Figure 7 Signaling flow 700 for exchanging messages 1 and 2 according to some example embodiments of the present disclosure is shown.

[0120] like Figure 7 As shown, at 705, the CPU executes a DL SYN with multiple APs 505-1, 505-2, ..., 505-n to allocate the same access resources, such as preambles, frequency domain resources, and time domain resources. At 710, the UE 510 implements a DL SYN with potential APs 505-1, 505-2, ..., 505-n to obtain access-related configurations and selects a potential serving DL AP as a candidate DL AP. At 715, the UE 510 generates message 1, which contains a list of candidate DL AP IDs, access resource indications, and other access-related information. The processing at 705, 710, and 715 is similar to that at 520, 525, and 530, and will not be described again for simplicity.

[0121] At 720, UE 510 sends Message 1 only to AP 505-2. At 725, AP 505-2 successfully decodes Message 1, and at 730, AP 505-2 forwards Message 1 to CPU 515. Message 1 includes a list of DL APs, access resource indications, etc. At 735, CPU 515 distinguishes between different access requests from different UEs, assigns a UE ID to UE 510, identifies the primary DL AP and other serving DL APs, schedules Message 3 on (multiple) temporary UL APs, and formulates Message 2, which includes the UE ID, a list of primary DL AP IDs and serving DL AP IDs, TAs for (multiple) temporary UL APs, and resources scheduled for Message 3. At 740, CPU 515 sends Message 2 to AP 505-2. At 745, CPU 515 sends scheduling information for Message 3 to APs 505-1 and 505-2. At 750, AP 505-2 sends Message 3 to UE 510.

[0122] Figure 8 Signaling flow 800 for exchanging messages 3 and 4 according to some example embodiments of the present disclosure is shown.

[0123] like Figure 8 As shown, at 805, UE 510 decodes message 2 and obtains the UE ID, UL / DL AP list, TA list, and scheduling information for message 3. At 810, UE 510 transmits message 3 to AP 505-2, which is the primary UL AP. Other serving UL APs, such as AP505-1 and 505-n, can also detect message 3 from UE 510. At 812, UE 510 begins checking the control channel on the primary DL AP (e.g., AP 505-1) for message 4 reception.

[0124] At 815, AP 505-2 decodes message 3, and at 820, AP 505-2 forwards message 3 to CPU 515 for connection-related configuration. Optionally, at 825, AP 505-1 can perform a measurement of the received power of message 3 and calculate TA information. Similarly, at 830, AP 505-n can perform a measurement of the received power of message 3 and calculate TA information. Then, APs 505-1 and 505-n can send message 3, along with the received power indication and TA information, to CPU 515 at (835).

[0125] At 845, CPU 515 retrieves the information from message 3, executes connection-related procedures, selects the primary UL AP and other serving UL APs, calculates the corresponding TA value for each selected UL AP, and generates message 4. At 850, CPU 515 sends message 4 to AP 505-1, which is the primary DLAP. At 855, AP 505-1 transmits message 4 to UE 510 to confirm the connection establishment. At 860, UE 510 receives message 4 from the primary DL AP and obtains information about the primary UL AP and potential serving UL APs, as well as the relevant TA value for each UL AP.

[0126] As referenced above Figure 5 and Figure 6 All the operations and processes described also apply to processes 700 and 800 and have similar effects. For simplicity, details will be omitted.

[0127] The three embodiments described above provide an access procedure to support cellless MIMO transmission in the 6G era. Multiple access points (APs) for both UL and DL communication can be determined separately during the access procedure to benefit from cellless MIMO transmission. Furthermore, multiple APs can be utilized for receiving / transmitting to increase the success rate of the access and connection establishment process. Additionally, serving DL and UL APs can be selected independently, allowing for the support of different UL / DL serving APs and ensuring simultaneous optimization of UL and DL communication.

[0128] Figure 9 A flowchart of an example method 300 according to some example embodiments of the present disclosure is shown. Method 300 may be implemented by network device 110. For discussion purposes, reference will be made to... Figure 1 Let's describe method 300.

[0129] In block 305, network device 110 determines an update mode for one or more currently configured parameters for use by terminal device 210 in inactive mode to initiate a connection recovery attempt. For example, network device 110 can configure which input parameters (KEY, PDCP COUNT, MESSAGE DIRECTION, BEARER) the UE will update and which step size to use. In some example embodiments, network device 110 can configure the order in which the input parameters need to be updated by terminal device 210. In some example embodiments, one of the parameters (e.g., the PDCP COUNT used for resumeMAC-I generation) can be specified to be updated when the update mode is configured by network device 110.

[0130] In box 310, network device 110 sends an indication to terminal device 210 of an update mode for one or more currently configured parameters. For example, when releasing terminal device 210 to an inactive mode such as RRC_INACTIVE mode, network device 110 may send an indication of how terminal device 210 will update the input parameters for resumeMAC-I to generate a new resumeMAC-I (for SDT or non-SDT) for connection recovery attempts.

[0131] In box 315, network device 110 detects a connection restoration attempt from terminal device 210 using one or more updated parameters generated by updating one or more parameters based on an update mode. For example, network device 110 can use one or more updated parameters to detect a connection restoration request from terminal device 210. The connection restoration request may include a resumeMAC-I generated based on one or more updated parameters.

[0132] In some example embodiments, terminal device 210 may not perform an SDT procedure with an updated resumeMAC-I, but instead perform only a non-SDT procedure (such as a regular RRC recovery procedure), for example, after an SDT procedure is rejected, or during an SDT procedure when non-SDT data arrives or a cell reselection occurs. Based on the updated resumeMAC-I, network device 110 can infer that terminal device 210 has previously performed an SDT. In this case, when the connection is restored, network device 110 can trigger a key change for the SDT-DRB and the reconstruction of (multiple) PDCP entities (because they may have already used the key for data during SDT transmission). For example, upon completion of a connection restoration procedure initiated by terminal device 210, network device 110 can transmit to terminal device 210 an indication of the changed value of the key for the bearer, including the SDT DRB or other bearers.

[0133] In some example embodiments, network device 110 can configure how many recovery attempts terminal device 210 can perform by updating input parameters. After the maximum number of recovery attempts has been performed, terminal device 210 can enter idle mode.

[0134] In some example embodiments, network device 110 may indicate to terminal device 210 whether input parameters should be updated. If input parameter updates are not allowed, terminal device 210 may enter an idle mode. This indication may be transmitted in a connection rejection message such as an RRC rejection message.

[0135] Figure 9 A flowchart of an example method 900 according to some example embodiments of the present disclosure is shown. Method 900 can be implemented as follows: Figure 2 The terminal device 210 shown is implemented here. For ease of discussion, reference will be made to... Figure 2 Description method 900.

[0136] In block 910, terminal device 210 transmits an access request to the first group of uplink access network devices, containing a list of identifiers of candidate downlink access network devices. In block 920, terminal device 210 receives an access response from the first group of downlink access network devices.

[0137] In some example embodiments, the access request may also include an access resource indication.

[0138] In some example embodiments, the access response may include at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

[0139] In some example embodiments, the access response may include one or more scheduled uplink resources for a connection establishment request. The terminal device 210 may also transmit the connection establishment request to a second set of uplink access network devices on one or more scheduled uplink resources. Furthermore, the terminal device 210 may receive a connection establishment response from the second set of downlink access network devices.

[0140] In some example embodiments, the connection establishment response may include at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

[0141] In some example embodiments, the first group of uplink access network devices may include multiple uplink access network devices. The terminal device 210 can transmit access requests by continuously transmitting access requests to the corresponding uplink access network devices among the multiple uplink access network devices.

[0142] In some example embodiments, terminal device 210 can receive an access response by continuously detecting multiple versions of access responses from the first group of downlink access network devices. Furthermore, terminal device 210 can perform a combination of the multiple versions of the access response.

[0143] In some example implementations, the identifiers of candidate downlink access network devices are sorted based on the received power of signals from the candidate downlink access network devices.

[0144] Figure 10 A flowchart of an example method 1000 according to some example embodiments of the present disclosure is shown. Method 1000 can be implemented as follows: Figure 2 The central network equipment shown is implemented in 220 locations. For ease of discussion, reference will be made to... Figure 2 Description method 1000.

[0145] In box 1010, the central network device 220 receives an access request from the terminal device via a group (referred to as the third group) of uplink access network devices, containing a list of identifiers of candidate downlink access network devices. In box 1020, the central network device 220 transmits an access response to the terminal device via the first group of downlink access network devices.

[0146] In some example embodiments, the access request may also include an access resource indication.

[0147] In some example embodiments, the access response may include one or more scheduling resources for a connection establishment request from the terminal device. The central network device 220 may also receive the connection establishment request from the terminal device via a group (referred to as the fourth group) of uplink access network devices. Furthermore, the central network device 220 may transmit the connection establishment response to the terminal device via a second group of downlink access network devices.

[0148] In some example embodiments, the access response may include a list of identifiers of serving uplink access network devices. The central network device 220 may also receive a set of receive power indications for the access request from the third set of uplink access network devices. Furthermore, the central network device 220 may, at least in part, determine one or more uplink access network devices in the third set of uplink access network devices as one or more serving uplink access network devices for the terminal device based on this set of receive power indications.

[0149] In some example embodiments, the fourth group of uplink access network devices may be selected from one or more serving uplink access network devices.

[0150] In some example embodiments, the connection establishment response may include a list of identifiers of serving uplink access network devices. The central network device 220 may also receive a set of receive power indications for the connection establishment request from the fourth group of uplink access network devices. Furthermore, the central network device 220 may determine one or more uplink access network devices in the fourth group of uplink access network devices as one or more serving uplink access network devices for the terminal device based on this set of receive power indications.

[0151] In some example embodiments, the central network device 220 may also transmit a received power indication instruction reporting a connection establishment request to a fifth group of uplink access network devices, the fifth group of uplink access network devices including at least the fourth group of uplink access network devices.

[0152] In some example embodiments, the third group of uplink access network devices may include multiple uplink access network devices in the access cluster. The central network device 220 may also allocate access-related resources to the uplink access network devices in the access cluster.

[0153] In some example embodiments, the central network device 220 may also determine one or more serving downlink access network devices based on a list of identifiers of candidate downlink access network devices. Furthermore, the access response or connection establishment response may include a list of identifiers of the determined one or more serving downlink access network devices.

[0154] In some example embodiments, the second group of downlink access network devices may be selected from one or more of the determined serving downlink access network devices.

[0155] In some example implementations, the identifiers of candidate downlink access network devices can be sorted based on the received power of signals from the candidate downlink access network devices.

[0156] In some example embodiments, the access request may also include an access resource indication. The central network device 220 may also identify that the access request was transmitted by a terminal device based on at least one of the access resource indication, a list of identifiers of candidate downlink access network devices, or an order of the identifiers of candidate downlink access network devices.

[0157] Those skilled in the art will understand that the above references Figures 2-4 All the operations and features described also apply to method 1000 and have similar effects.

[0158] Figure 11 A flowchart of an example method 1100 according to some example embodiments of the present disclosure is shown. Method 1100 can be implemented as follows: Figure 2This is implemented at the first uplink access network device 230-1 shown. For discussion purposes, reference will be made to... Figure 2 Description method 1100.

[0159] In box 1110, the first uplink access network device 230-1 receives an access request from the terminal device, the access request containing a list of identifiers of candidate downlink access network devices. In box 1120, the first uplink access network device 230-1 forwards the access request to the central network device.

[0160] In some example implementations, the identifiers of candidate downlink access network devices can be sorted based on the received power of signals from the candidate downlink access network devices.

[0161] In some example embodiments, the first uplink access network device 230-1 may also send a receive power indication of the access request to the central network device.

[0162] Figure 12 A flowchart of an example method 1200 according to some example embodiments of the present disclosure is shown. Method 1200 can be implemented as follows: Figure 2 This is implemented at the second uplink access network device 230-2 shown. For discussion purposes, reference will be made to... Figure 2 Description method 1200.

[0163] In box 1210, the second uplink access network device 230-2 receives a connection establishment request from the terminal device. In box 1220, the second uplink access network device 230-2 forwards the connection establishment request to the central network device. In box 1230, the second uplink access network device 230-2 transmits a receive power indication of the connection establishment request to the central network device.

[0164] In some example embodiments, the second uplink access network device 230-2 can receive a connection establishment request from the terminal device in response to receiving an instruction from the central network device to receive a connection establishment request.

[0165] In some example embodiments, the second uplink access network device 230-2 can transmit the receive power indication of the connection establishment request to the central network device in response to receiving an instruction from the central network device that reports a receive power indication of the connection establishment request.

[0166] As referenced above Figures 2-8 All the operations and features described also apply to methods 900 through 1200 and have similar effects. For simplicity, details will be omitted.

[0167] Figure 13 This is a simplified block diagram of a device 1300 suitable for implementing an example embodiment of the present disclosure.

[0168] As shown in the figure, device 1300 includes a processor 1310, a memory 1320 coupled to the processor 1310, a communication module 1330 coupled to the processor 1310, and a communication interface (not shown) coupled to the communication module 1330. The memory 1320 stores at least a program 1340. The communication module 1330 is used for bidirectional communication, for example, via multiple antennas. The communication interface can represent any interface required for communication.

[0169] Assume that program 1340 includes program instructions that, when executed by the associated processor 1310, enable device 1300 to operate according to an example embodiment of this disclosure, as referenced herein. Figures 2-12 The exemplary embodiments described herein may be implemented by computer software executable by the processor 1310 of device 1300, or by hardware, or by a combination of software and hardware. The processor 1310 may be configured to implement various exemplary embodiments of this disclosure.

[0170] Memory 1320 can be of any type suitable for a local technology network and can be implemented using any suitable data storage technology, such as, as non-limiting examples, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Although only one memory 1320 is shown in device 1300, several physically different memory modules may be present in device 1300. Processor 1310 can be of any type suitable for a local technology network and, as non-limiting examples, may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 1300 may have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0171] When device 1300 acts as terminal device 210, processor 1310 and communication module 1330 can cooperate to implement the operations and features of terminal device 210, as shown above. Figures 2-12 As described above, when device 1300 acts as the first UL access network device 230-1 or the second UL access network device 230-2, processor 1310 and communication module 1330 can cooperate to implement the operations and features at the first UL access network device 230-1 or the second UL access network device 230-2, as referenced above. Figures 2-12As described above, when device 1300 acts as central network device 220, processor 1310 and communication module 1330 can cooperate to implement the operations and features of central network device 220, as referenced above. Figures 2-12 As stated above.

[0172] The above reference Figures 2-12 All the operations and features described also apply to device 1300 and have similar effects. For simplicity, details will be omitted.

[0173] Generally, the various exemplary embodiments of this disclosure can be implemented using hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented using hardware, while others can be implemented using firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the exemplary embodiments of this disclosure are illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented using hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0174] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, which execute in a device targeting a real or virtual processor to perform the functions described above. Figures 2-12 The described method, process, or signaling flow. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various example embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions of a program module can execute on a local or distributed device. In a distributed device, a program module can reside on both local and remote storage media.

[0175] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0176] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals and computer-readable media.

[0177] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination of the foregoing. More specific examples of computer-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), digital versatile optical disc (DVD), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0178] Furthermore, although operations are described in a specific order, this should not be construed as requiring the operations to be performed in the specific order shown or sequentially, or to perform all of the shown operations to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure, but rather as descriptions of features that may be specific to particular example embodiments. Certain features described in the context of individual example embodiments may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple example embodiments.

[0179] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that this disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms of implementing the claims.

[0180] Various example embodiments of these technologies have been described. The following embodiments are described as a supplement to or alternative to the foregoing. Features described in any of the following examples may be used in conjunction with any other examples described herein.

[0181] In some aspects, one method includes: a terminal device transmitting an access request containing a list of identifiers of candidate downlink access network devices to a first group of uplink access network devices; and the terminal device receiving an access response from the first group of downlink access network devices.

[0182] In some example embodiments, the access request also includes an access resource indication.

[0183] In some example embodiments, the access response includes at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

[0184] In some example embodiments, the access response includes one or more scheduled uplink resources for a connection establishment request, and the method further includes: the terminal device transmitting a connection establishment request to a second group of uplink access network devices on the one or more scheduled uplink resources; and the terminal device receiving a connection establishment response from the second group of downlink access network devices.

[0185] In some example embodiments, the connection establishment response includes at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

[0186] In some exemplary embodiments, the first group of uplink access network devices includes multiple uplink access network devices, and transmitting the access request includes: the terminal device continuously transmitting the access request to the corresponding uplink access network device among the multiple uplink access network devices.

[0187] In some example embodiments, receiving the access response includes: the terminal device continuously detecting multiple versions of the access response from the first group of downlink access network devices; and performing a combination of the multiple versions of the access response.

[0188] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0189] In some aspects, one method includes: receiving an access request from a terminal device via a third set of uplink access network devices, comprising an access request containing identifiers of candidate downlink access network devices; and transmitting an access response from the central network device to the terminal device via a first set of downlink access network devices.

[0190] In some example embodiments, the access request also includes an access resource indication.

[0191] In some example embodiments, the access response includes one or more scheduling resources for the connection establishment request of the terminal device, and the method further includes: receiving the connection establishment request from the terminal device by the central network device via a fourth set of uplink access network devices; and transmitting the connection establishment response to the terminal device by the central network device via a second set of downlink access network devices.

[0192] In some example embodiments, the access response includes a list of identifiers of serving uplink access network devices, and the method further includes: receiving a set of receive power indications of the access request from the third set of uplink access network devices; and identifying one or more uplink access network devices in the third set of uplink access network devices as one or more serving uplink access network devices of the terminal device, based at least in part on the set of receive power indications.

[0193] In some example embodiments, the fourth group of uplink access network devices is selected from the one or more serving uplink access network devices.

[0194] In some example embodiments, the connection establishment response includes a list of identifiers of serving uplink access network devices, and the method further includes: receiving a set of receive power indications from the fourth set of uplink access network devices for the connection establishment request; and identifying one or more uplink access network devices in the fourth set of uplink access network devices as one or more serving uplink access network devices of the terminal device based on the set of receive power indications.

[0195] In some example embodiments, the method further includes: transmitting an instruction to a fifth group of uplink access network devices reporting a receive power indication of the connection establishment request, the fifth group of uplink access network devices including at least the fourth group of uplink access network devices.

[0196] In some example embodiments, the third group of uplink access network devices includes multiple uplink access network devices in the access cluster, and the method further includes: allocating access-related resources to the uplink access network devices in the access cluster.

[0197] In some example embodiments, the method further includes: determining one or more serving downlink access network devices based on the list of identifiers of the candidate downlink access network devices. Further, the access response or the connection establishment response includes the determined list of identifiers of the one or more serving downlink access network devices.

[0198] In some example embodiments, the second group of downlink access network devices is selected from one or more of the determined serving downlink access network devices.

[0199] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0200] In some example embodiments, the access request further includes an access resource indication, and the method further includes identifying that the access request is transmitted by the terminal device based on at least one of the access resource indication, the list of identifiers of the candidate downlink access network devices, or the order of the identifiers of the candidate downlink access network devices.

[0201] In some aspects, one method includes: receiving an access request from a terminal device by a first uplink access network device, the access request including a list of identifiers of candidate downlink access network devices; and forwarding the access request from the first uplink access network device to a central network device.

[0202] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0203] In some example embodiments, the method further includes sending a receive power indication of the access request to the central network device.

[0204] In some aspects, one method includes: receiving a connection establishment request from a terminal device by a second uplink access network device; forwarding the connection establishment request from the second uplink access network device to a central network device; and transmitting a receive power indication of the connection establishment request from the second uplink access network device to the central network device.

[0205] In some example embodiments, receiving the connection establishment request from the terminal device includes: receiving the connection establishment request from the terminal device in response to receiving an instruction from the central network device to receive the connection establishment request.

[0206] In some example embodiments, transmitting the receive power indication of the connection establishment request to the central network device includes: in response to receiving an instruction from the central network device to report the receive power indication of the connection establishment request, transmitting the receive power indication of the connection establishment request to the central network device.

[0207] In some aspects, an apparatus implemented at a terminal device includes: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured together with the at least one processor to cause the apparatus to: transmit an access request to a first group of uplink access network devices containing a list of identifiers of candidate downlink access network devices; and receive an access response from the first group of downlink access network devices.

[0208] In some example embodiments, the access request also includes an access resource indication.

[0209] In some example embodiments, the access response includes at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

[0210] In some example embodiments, the access response includes one or more scheduled uplink resources for a connection establishment request, and the apparatus is further configured to: transmit a connection establishment request to a second set of uplink access network devices on the one or more scheduled uplink resources; and receive a connection establishment response from the second set of downlink access network devices.

[0211] In some example embodiments, the connection establishment response includes at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

[0212] In some exemplary embodiments, the first group of uplink access network devices includes a plurality of uplink access network devices, and the apparatus is configured to transmit the access request by continuously transmitting the access request from the terminal device to a corresponding uplink access network device among the plurality of uplink access network devices.

[0213] In some example embodiments, the apparatus is configured to receive the access response by: continuously detecting multiple versions of the access response from the first group of downlink access network devices by the terminal device; and performing a combination of the multiple versions of the access response.

[0214] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0215] In some aspects, an apparatus implemented at a central network device includes: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured together with the at least one processor to cause the apparatus to: receive an access request from a terminal device via a third set of uplink access network devices, containing a list of identifiers of candidate downlink access network devices; and transmit an access response to the terminal device via a first set of downlink access network devices.

[0216] In some example embodiments, the access request also includes an access resource indication.

[0217] In some example embodiments, the access response includes one or more scheduling resources for the connection establishment request of the terminal device, and the apparatus is further configured to: receive the connection establishment request from the terminal device via a fourth set of uplink access network devices; and transmit the connection establishment response to the terminal device via a second set of downlink access network devices.

[0218] In some example embodiments, the access response includes a list of identifiers of serving uplink access network devices, and the apparatus is further configured to: receive a set of receive power indications of the access request from the third set of uplink access network devices; and identify one or more uplink access network devices in the third set of uplink access network devices as one or more serving uplink access network devices of the terminal device, at least in part based on the set of receive power indications.

[0219] In some example embodiments, the fourth group of uplink access network devices is selected from the one or more serving uplink access network devices.

[0220] In some example embodiments, the connection establishment response includes a list of identifiers of serving uplink access network devices, and the apparatus is further configured to: receive a set of receive power indications from the fourth set of uplink access network devices for the connection establishment request; and identify one or more uplink access network devices in the fourth set of uplink access network devices as one or more serving uplink access network devices of the terminal device based on the set of receive power indications.

[0221] In some example embodiments, the apparatus is further configured to transmit an instruction to a fifth group of uplink access network devices reporting a receive power indication of the connection establishment request, the fifth group of uplink access network devices including at least the fourth group of uplink access network devices.

[0222] In some example embodiments, the third group of uplink access network devices includes multiple uplink access network devices in the access cluster, and the apparatus is further configured to: allocate access-related resources to the uplink access network devices in the access cluster.

[0223] In some example embodiments, the apparatus is further configured to: determine one or more serving downlink access network devices based on a list of identifiers of the candidate downlink access network devices, wherein the access response or the connection establishment response includes a list of identifiers of the determined one or more serving downlink access network devices.

[0224] In some example embodiments, the second group of downlink access network devices is selected from one or more of the determined serving downlink access network devices.

[0225] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0226] In some example embodiments, the access request further includes an access resource indication, and the device is further configured to identify that the access request is transmitted by the terminal device based on at least one of the access resource indication, the list of identifiers of the candidate downlink access network devices, or the order of the identifiers of the candidate downlink access network devices.

[0227] In some aspects, an apparatus implemented at a first uplink access network device includes: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured together with the at least one processor such that the apparatus: receives an access request from a terminal device, the access request containing an identifier list of candidate downlink access network devices; and forwards the access request to a central network device.

[0228] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0229] In some example embodiments, the apparatus is also configured to send a receive power indication of the access request to the central network device.

[0230] In some aspects, an apparatus implemented at a second uplink access network device includes: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured together with the at least one processor such that the apparatus: receives a connection establishment request from a terminal device by the second uplink access network device; forwards the connection establishment request to a central network device; and transmits a receive power indication of the connection establishment request to the central network device.

[0231] In some example embodiments, the apparatus is configured to receive the connection establishment request from the terminal device in such a way that it receives the connection establishment request from the terminal device in response to receiving an instruction from the central network device to receive the connection establishment request.

[0232] In some example embodiments, the apparatus is configured to transmit the receive power indication of the connection establishment request to the central network device in such a way that, in response to receiving an instruction from the central network device to report the receive power indication of the connection establishment request, the apparatus transmits the receive power indication of the connection establishment request to the central network device.

[0233] In some aspects, an apparatus includes: components for transmitting an access request, comprising an identifier list of candidate downlink access network devices, from a terminal device to a first group of uplink access network devices; and components for receiving an access response from the first group of downlink access network devices by the terminal device.

[0234] In some example embodiments, the access request also includes an access resource indication.

[0235] In some example embodiments, the access response includes at least one of a list of identifiers for serving uplink access network devices or a list of identifiers for serving downlink access network devices.

[0236] In some example embodiments, the access response includes one or more scheduled uplink resources for a connection establishment request, and the apparatus further includes: components for transmitting the connection establishment request from the terminal device to a second set of uplink access network devices on the one or more scheduled uplink resources; and components for receiving a connection establishment response from the second set of downlink access network devices by the terminal device.

[0237] In some example embodiments, the connection establishment response includes at least one of a list of identifiers for serving uplink access network devices or a list of identifiers for serving downlink access network devices.

[0238] In some example embodiments, the first group of uplink access network devices includes multiple uplink access network devices, and the component for transmitting the access request includes: a component for continuously transmitting the access request from the terminal device to a corresponding uplink access network device among the multiple uplink access network devices.

[0239] In some example embodiments, the component for receiving the access response includes: a component for continuously detecting multiple versions of the access response from the first group of downlink access network devices by the terminal device; and a component for combining the multiple versions of the access response.

[0240] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0241] In some aspects, an apparatus includes: components for receiving, by a central network device, an access request from a terminal device via a third set of uplink access network devices, comprising an identification list of candidate downlink access network devices; and components for transmitting, by the central network device, an access response to the terminal device via a first set of downlink access network devices.

[0242] In some example embodiments, the access request also includes an access resource indication.

[0243] In some example embodiments, the access response includes one or more scheduling resources for the connection establishment request of the terminal device, and the apparatus further includes: components for receiving the connection establishment request from the terminal device by the central network device via a fourth set of uplink access network devices; and components for transmitting the connection establishment response from the central network device to the terminal device via a second set of downlink access network devices.

[0244] In some example embodiments, the access response includes a list of identifiers of serving uplink access network devices, and the apparatus further includes: a set of receive power indications for receiving the access request from the third set of uplink access network devices; and a set of components for identifying one or more uplink access network devices in the third set of uplink access network devices as one or more serving uplink access network devices of the terminal device, at least in part based on the set of receive power indications.

[0245] In some example embodiments, the fourth group of uplink access network devices is selected from the one or more serving uplink access network devices.

[0246] In some example embodiments, the connection establishment response includes a list of identifiers of serving uplink access network devices, and the apparatus further includes: a set of receive power indications for receiving the connection establishment request from the fourth set of uplink access network devices; and a set of receive power indications for identifying one or more uplink access network devices in the fourth set of uplink access network devices as one or more serving uplink access network devices of the terminal device.

[0247] In some example embodiments, the apparatus further includes: a component for transmitting an instruction to a fifth group of uplink access network devices reporting a receive power indication of the connection establishment request, the fifth group of uplink access network devices including at least the fourth group of uplink access network devices.

[0248] In some example embodiments, the third group of uplink access network devices includes multiple uplink access network devices in the access cluster, and the apparatus further includes a component for allocating access-related resources to the uplink access network devices in the access cluster.

[0249] In some example embodiments, the apparatus further includes components for determining one or more serving downlink access network devices based on the list of identifiers of the candidate downlink access network devices. Further, the access response or the connection establishment response includes the determined list of identifiers of the one or more serving downlink access network devices.

[0250] In some example embodiments, the second group of downlink access network devices is selected from one or more of the determined serving downlink access network devices.

[0251] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0252] In some example embodiments, the access request further includes an access resource indication, and the apparatus further includes a component for identifying that the access request is transmitted by the terminal device based on at least one of the access resource indication, the list of identifiers of the candidate downlink access network devices, or the order of the identifiers of the candidate downlink access network devices.

[0253] In some aspects, an apparatus includes: components for receiving an access request from a terminal device by a first uplink access network device, the access request including a list of identifiers of candidate downlink access network devices; and components for forwarding the access request from the first uplink access network device to a central network device.

[0254] In some example embodiments, the identifiers of the candidate downlink access network devices are sorted based on the received power of the signals from the candidate downlink access network devices.

[0255] In some example embodiments, the apparatus further includes a component for sending a receive power indication of the access request to the central network device.

[0256] In some aspects, an apparatus includes: components for receiving a connection establishment request from a terminal device by a second uplink access network device; components for forwarding the connection establishment request from the second uplink access network device to a central network device; and components for transmitting a receive power indication of the connection establishment request from the second uplink access network device to the central network device.

[0257] In some example embodiments, the component for receiving the connection establishment request from the terminal device includes: a component for receiving the connection establishment request from the terminal device in response to receiving an instruction from the central network device to receive the connection establishment request.

[0258] In some example embodiments, the component for transmitting the receive power indication of the connection establishment request to the central network device includes: a component for transmitting the receive power indication of the connection establishment request to the central network device in response to receiving an instruction from the central network device to report the receive power indication of the connection establishment request.

[0259] In some aspects, a computer-readable storage medium includes program instructions stored thereon that, when executed by a processor of a device, cause the device to perform a method according to some example embodiments of the present disclosure.

Claims

1. A method for communication, comprising: The terminal device transmits an access request to a first group of uplink access network devices, which includes a list of identifiers of candidate downlink access network devices, wherein the first group of uplink access network devices includes multiple uplink access network devices; The terminal device receives an access response from the first group of downlink access network devices; The transmission of the access request includes: The terminal device continuously transmits the access request to the corresponding uplink access network device among the plurality of uplink access network devices; and Receiving the access response includes: The terminal device continuously detects multiple versions of the access response from the first group of downlink access network devices; and The terminal device performs a combination of the multiple versions of the access response.

2. The method according to claim 1, wherein the access request further includes an access resource indication.

3. The method of claim 1, wherein the access response comprises at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

4. The method of claim 1, wherein the access response includes one or more scheduled uplink resources for a connection establishment request, and the method further comprises: The terminal device transmits a connection establishment request to the second group of uplink access network devices on one or more scheduled uplink resources; as well as The terminal device receives a connection establishment response from the second group of downlink access network devices.

5. The method of claim 4, wherein the connection establishment response includes at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

6. The method according to any one of claims 1 to 5, wherein the identifier of the candidate downlink access network device is sorted based on the received power of the signal from the candidate downlink access network device.

7. A method for communication, comprising: The central network equipment receives an access request from the terminal equipment via a third group of uplink access network equipment, containing a list of identifiers of candidate downlink access network equipment. The central network device transmits an access response to the terminal device via the first group of downlink access network devices; The access response includes one or more scheduling resources for the connection establishment request of the terminal device, and the method further includes: The central network device receives a connection establishment request from the terminal device via the fourth group of uplink access network devices; and The central network device transmits a connection establishment response to the terminal device via the second set of downlink access network devices; and The access response includes a list of identifiers of the serving uplink access network devices, and the method further includes: A set of receive power indications for the access request received from the third group of uplink access network devices; and Based at least in part on the set of received power indications, one or more uplink access network devices in the third set of uplink access network devices are identified as one or more serving uplink access network devices for the terminal device, wherein the fourth set of uplink access network devices is selected from the one or more serving uplink access network devices.

8. The method of claim 7, wherein the access request further includes an access resource indication.

9. The method of claim 7, wherein the connection establishment response includes a list of identifiers of the serving uplink access network device, and the method further comprises: Receive a set of receive power indications from the fourth group of uplink access network devices to request the connection establishment; as well as Based on the aforementioned set of received power indications, one or more uplink access network devices in the fourth set of uplink access network devices are identified as one or more serving uplink access network devices for the terminal device.

10. The method of claim 9, further comprising: The instruction to transmit a receive power indication reporting the connection establishment request to the fifth group of uplink access network devices, the fifth group of uplink access network devices including at least the fourth group of uplink access network devices.

11. The method according to any one of claims 7 to 10, wherein the third group of uplink access network devices comprises a plurality of uplink access network devices in the access cluster, and the method further comprises: Allocate access-related resources to the uplink access network devices in the access cluster.

12. The method according to any one of claims 7 to 10, further comprising: Based on the list of identifiers of the candidate downlink access network devices, one or more serving downlink access network devices are determined. The access response or connection establishment response contains a list of identifiers of one or more service downlink access network devices.

13. The method of claim 12, wherein the second group of downlink access network devices is selected from one or more of the determined serving downlink access network devices.

14. The method according to any one of claims 7 to 10, wherein the identifier of the candidate downlink access network device is sorted based on the received power of the signal from the candidate downlink access network device.

15. The method of claim 14, wherein the access request further includes an access resource indication, and the method further includes: The access request is identified as being transmitted by the terminal device based on at least one of the access resource indication, the list of identifiers of the candidate downlink access network devices, or the order of the identifiers of the candidate downlink access network devices.

16. A communication apparatus implemented at a terminal device, comprising: At least one processor; as well as At least one memory, including computer program code; The at least one memory and the computer program code are configured together with the at least one processor such that the device: An access request is transmitted to a first group of uplink access network devices, which includes a list of identifiers of candidate downlink access network devices, wherein the first group of uplink access network devices includes multiple uplink access network devices; Receive access response from the first group of downlink access network devices; The device is configured to transmit the access request in the following manner: The access request is continuously transmitted to the corresponding uplink access network device among the plurality of uplink access network devices; and The device is configured to receive the access response in the following manner: Continuously detect multiple versions of the access response from the first group of downlink access network devices; and The multiple versions of the access response are combined.

17. The apparatus of claim 16, wherein the access request further includes an access resource indication.

18. The apparatus of claim 16, wherein the access response comprises at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

19. The apparatus of claim 16, wherein the access response includes one or more scheduled uplink resources for a connection establishment request, and the apparatus is further configured to: Transmit a connection establishment request to the second group of uplink access network devices on one or more scheduled uplink resources; and Receive connection establishment response from the second group of downlink access network devices.

20. The apparatus of claim 19, wherein the connection establishment response includes at least one of a list of identifiers of serving uplink access network devices or a list of identifiers of serving downlink access network devices.

21. The apparatus of any one of claims 16 to 20, wherein the identifiers of the candidate downlink access network devices are sorted based on the received power of signals from the candidate downlink access network devices.

22. A communication apparatus implemented at a central network device, comprising: At least one processor; as well as At least one memory, including computer program code; The at least one memory and the computer program code are configured together with the at least one processor such that the device: The terminal device receives an access request containing a list of identifiers of candidate downlink access network devices via a third group of uplink access network devices. The access response is transmitted to the terminal device via the first group of downlink access network devices; The access response includes one or more scheduling resources for the connection establishment request of the terminal device, and the means is further configured to: The connection establishment request is received from the terminal device via the fourth group of uplink access network devices; as well as A connection establishment response is transmitted to the terminal device via the second group of downlink access network devices; and The access response includes a list of identifiers of the serving uplink access network devices, and the device is further configured to: A set of receive power indications are received from the third group of uplink access network devices to receive the access request; as well as Based at least in part on the set of received power indications, one or more uplink access network devices in the third set of uplink access network devices are identified as one or more serving uplink access network devices of the terminal device, wherein the fourth set of uplink access network devices is selected from the one or more serving uplink access network devices.

23. The apparatus of claim 22, wherein the access request further includes an access resource indication.

24. The apparatus of claim 22, wherein the connection establishment response comprises a list of identifiers of serving uplink access network devices, and the apparatus is further configured to: Receive a set of receive power indications from the fourth group of uplink access network devices to request the connection establishment; and Based on the aforementioned set of received power indications, one or more uplink access network devices in the fourth set of uplink access network devices are identified as one or more serving uplink access network devices for the terminal device.

25. The apparatus of claim 24, wherein the apparatus is further configured to: The instruction to transmit a receive power indication reporting the connection establishment request to the fifth group of uplink access network devices, the fifth group of uplink access network devices including at least the fourth group of uplink access network devices.

26. The apparatus according to any one of claims 22 to 25, wherein the third group of uplink access network devices comprises a plurality of uplink access network devices in an access cluster, and the apparatus is further configured to: Allocate access-related resources to the uplink access network devices in the access cluster.

27. The apparatus according to any one of claims 22 to 25, wherein the apparatus is further configured to: Based on the list of identifiers of the candidate downlink access network devices, one or more serving downlink access network devices are determined. The access response or connection establishment response contains a list of identifiers of one or more service downlink access network devices.

28. The apparatus of claim 27, wherein the second group of downlink access network devices is selected from one or more of the determined serving downlink access network devices.

29. The apparatus of any one of claims 22 to 25, wherein the identifier of the candidate downlink access network device is sorted based on the received power of the signal from the candidate downlink access network device.

30. The apparatus of claim 29, wherein the access request further includes an access resource indication, and the apparatus is further configured to: The access request is identified as being transmitted by the terminal device based on at least one of the access resource indication, the list of identifiers of the candidate downlink access network devices, or the order of the identifiers of the candidate downlink access network devices.

31. A communication apparatus implemented at a terminal device, comprising: A component for transmitting an access request to a first group of uplink access network devices, comprising a list of identifiers of candidate downlink access network devices, wherein the first group of uplink access network devices includes a plurality of uplink access network devices; Components used to receive access responses from the first group of downlink access network devices; The component used for transmitting the access request includes: Components for continuously transmitting the access request to the corresponding uplink access network device among the plurality of uplink access network devices; and The component for receiving the access response includes: Components for continuously detecting multiple versions of the access response from the first group of downlink access network devices; and A component for combining the multiple versions of the access response.

32. A communication apparatus implemented at a central network device, comprising: A component for receiving an access request from a terminal device via a third group of uplink access network devices, which includes a list of identifiers of candidate downlink access network devices; Components for transmitting access responses to the terminal device via the first group of downlink access network devices; The access response includes one or more scheduling resources for the connection establishment request of the terminal device, and the apparatus further includes: Components for receiving connection establishment requests from the terminal device via the fourth group of uplink access network devices; and Components for transmitting a connection establishment response to the terminal device via a second set of downlink access network devices; and The access response includes a list of identifiers of the serving uplink access network devices, and the apparatus further includes: A set of receive power indicators for receiving the access request from the third set of uplink access network devices; and Components for identifying one or more uplink access network devices from the third group of uplink access network devices as one or more serving uplink access network devices of the terminal device, based at least in part on the set of received power indications, wherein the fourth group of uplink access network devices is selected from the one or more serving uplink access network devices.

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