Method and apparatus for forming self-organizing multi-hop millimeter wave backhaul links

Abstract

Embodiments of the present disclosure describe systems, devices, and methods for self-organizing multi-hop millimeter wave backhaul links. Various embodiments can include a relay node that receives discovery signal information from an eNB and measures millimeter wave discovery signals of other relay nodes based on the information. The measurements can be fed back to the eNB and used to create millimeter wave backhaul links. Other embodiments can be described or claimed.

Description

[0001] This application is a divisional application of Chinese invention patent application with international filing date of October 21, 2015, national application number 201580049487.5, and invention title "Method and apparatus for forming a self-organizing multi-hop millimeter-wave backhaul link".

[0002] Related applications

[0003] This application claims priority to U.S. Patent Application No. 62 / 066,787, filed October 21, 2014, and U.S. Patent Application No. 62 / 067,179, filed October 22, 2014, both of which are entitled “Self-Organized Multi-Hop Millimeter Wave Backhauling to support DynamicRouting and Cooperative Transmission”. Technical Field

[0004] The embodiments of this disclosure generally relate to the field of wireless communication, and more specifically, to methods and apparatus for multi-hop millimeter-wave backhaul support. Background Technology

[0005] Millimeter wave (mmWave) communication has been considered a promising technology to meet the expected requirements of 5G mobile systems. Typically, mmWave communication occurs in the extremely high frequency (EHF) band, which includes frequencies from 30 to 300 GHz.

[0006] The use of mmWave communication for backhaul link connections between base stations has already attracted significant research interest in both academia and industry. Two fundamental technical benefits of mmWave communication are anticipated. The first benefit is the provision of enormous bandwidth to support very high data rates of multiple gigabits per second with low latency. The second benefit is that good spatial separation between different links can be used to address propagation path loss. This is likely to increase spatial multiplexing, which translates into higher regional spectral efficiency. For example, signals to different links (or user equipment (UEs)) with different beam directions (these signals are called pencil beams) can, in some examples, have limited mutual interference. Thus, through Spatial Multiple Access (SDMA) technology, the same frequency resources can be simultaneously allocated to different links / UEs, thereby increasing spectral efficiency.

[0007] The main challenge in using mmWave spectrum in practical systems is the propagation loss caused by the very high radio frequency. As a result, the typical coverage of mmWave links is significantly smaller than that of traditional mobile broadband spectrum below 6 GHz used in LTE or other legacy systems. Attached Figure Description

[0008] The embodiments will be readily understood from the following detailed description, taken in conjunction with the accompanying drawings. For the purpose of this description, similar reference numerals denote similar structural elements. In the illustrations of the drawings, embodiments are shown by way of example rather than limitation.

[0009] Figure 1 A communication environment according to some embodiments is shown.

[0010] Figure 2 The discovery signal structure is shown according to some embodiments.

[0011] Figures 3-5 The various stages of the backhaul link establishment process according to some embodiments are illustrated.

[0012] Figure 6 A computing device according to some embodiments is shown.

[0013] Figure 7 A system according to some embodiments is shown. Detailed Implementation

[0014] Various aspects of the illustrative embodiments will be described using terminology generally employed by those skilled in the art to convey the essence of their work to others skilled in the art. However, those skilled in the art will understand that alternative embodiments may be implemented using only some of the aspects described. Specific figures, materials, and configurations are set forth for illustrative purposes to provide a thorough understanding of the illustrative embodiments. However, those skilled in the art will understand that alternative embodiments may be implemented without these specific details. In other instances, well-known features have been omitted or simplified without obscuring the embodiments shown.

[0015] Furthermore, the various operations will then be described as multiple discrete entities in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations must be performed in sequence. Specifically, these operations need not be performed in the order presented.

[0016] The phrase "in some embodiments" is used repeatedly. This phrase does not typically refer to the same embodiment; however, it is possible. The terms "comprising," "having," and "including" are synonymous unless the context otherwise indicates.

[0017] The phrases “A or B”, “A / B”, and “A and / or B” mean (A), (B) or (A and B).

[0018] As used herein, the term "circuit system" refers to or includes hardware components or part of hardware components, such as application-specific integrated circuits (ASICs), electronic circuits, logic circuits, (shared, dedicated, or grouped) processors, and / or (shared, dedicated, or grouped) memories configured to provide the described operations. In some embodiments, the circuit may execute one or more software or firmware programs to provide at least some of the described operations. In some embodiments, the circuit system may be implemented in one or more software or firmware modules, or the operations associated with the circuit system may be implemented by one or more software or firmware modules. In some embodiments, the circuit system may include logic that operates at least partially in hardware to perform the described operations.

[0019] As described above, the challenges of using mmWave spectrum may be related to the limited coverage of mmWave links. To provide sufficient backhaul link coverage, multi-hop relay backhaul can be used. This results in a series of multiple point-to-point (1-hop) links used as backhaul links from the target mmWave small cell base station to the anchor evolved Node B (eNB), which connects the access network to the core network.

[0020] Figure 1 A communication environment 100 according to various embodiments is summarized. The communication environment 100 may include an anchor eNB 104 of a macrocell coverage area 108 with broadband spectrum. The communication environment 100 may also include five relay nodes (RNs) deployed in the macrocell coverage area 108, such as RN-1 112, RN-2 116, RN-3 120, RN-4 124, and RN-5 128. At least one of these relay nodes may be capable of establishing an mmWave backhaul connection to the eNB 104.

[0021] eNB 104 and relay nodes can be equipped with mmWave Radio Access Technology (RAT) interfaces to communicate over mmWave communication links. mmWave communication links (or mmWave links) are... Figure 1 The numbers are indicated by lines with arrows bearing the corresponding label Ly, where y = 1, 2, ... 6.

[0022] A specific multi-hop backhaul link may include a number of mmWave links. For example, the backhaul link between RN-5 128 and eNB 104 may include L1, L2, L3, and L5 (referred to as path 1 (P1)), or it may include L1, L2, L4, and L6 (referred to as path 2 (P2)). Multi-hop backhaul links can be used to route uplink traffic, such as traffic from RN-5 128 to eNB 104, or to route downlink traffic, such as traffic from eNB 104 to RN-5 128.

[0023] To reduce the initial installation difficulty, it is desirable to build backhaul links in a self-organizing manner with minimal human interaction. To improve network power efficiency, it is desirable for certain relay nodes to be dynamically turned on and off based on traffic demand. Furthermore, in some cases, dynamic path switching or cooperative backhaul transmission is also anticipated to be advantageous for improving link reliability. Therefore, embodiments of this disclosure provide a self-organizing backhaul link establishment scheme that supports flexible dynamic path switching and possible cooperative transmission and / or reception.

[0024] This disclosure provides a signaling method to facilitate the establishment of the self-organizing multi-hop mmWave backhaul link mentioned above. Furthermore, it allows for flexible support of dynamic path switching and cooperative transmission in a manner transparent to the target relay node.

[0025] The relay nodes described herein can provide backhaul support and, in some embodiments, can also be configured to provide users with radio access via small cells (e.g., cells associated with a coverage area smaller than coverage area 108). The small cells provided by the relay nodes can be mmWave user access cells or mobile broadband user access cells, such as 3GPP Long Term Evolution (LTE) user access cells.

[0026] The eNB 104 can establish a Radio Resource Control (RRC) connection with the RN-5 128 using existing LTE procedures. The RRC connection can be established over a direct radio link between the eNB 104 and the RN-5 128, located, for example, in mobile broadband spectrum with frequencies below approximately 6 GHz.

[0027] eNB 104 can be used as the primary cell (PCell) for newly deployed mmWave relay nodes (e.g., RN-5 128). eNB 104 can send discovery information to the newly deployed node (e.g., RN-5 128) to provide information on how the newly deployed node will receive signals from other relay nodes (e.g., ...). Figure 1The newly deployed relay node can be an mmWave relay node that is connected to the macro cell eNBRRC but has not yet been linked to other mmWave relay nodes, as used herein.

[0028] The RN-5 128 can use discovery information provided by the eNB 104 to search for, detect, and measure discovery signals transmitted by other relay nodes (e.g., RN-3 120 and RN-4 124). In some embodiments, the discovery signal can be measured for received power or quality metrics. After measuring the discovery signal, the RN-5 128 can transmit a discovery signal report to the eNB 104 via the PCell.

[0029] The eNB 104 can use reported power or quality metrics to select one or more relay nodes to provide one or more corresponding secondary cells (SCells) for the RN-5128. The RN-5128 can then monitor backhaul link traffic on both the PCell provided by the eNB 104 and the one or more SCells provided by the one or more relay nodes.

[0030] The RN-5 128 can transmit a capability message to the eNB 104, indicating the number of parallel discovery signals that the RN-5 128 is capable of transmitting. Alternatively, this message can indicate the number of consecutive mmWave discovery signals that can be transmitted in the discovery cluster. This capability message can be transmitted to the eNB 104 via the PCell.

[0031] Upon receiving a capability message from RN-5 128, eNB 104 can configure and transmit instructions for discovery signal configuration information to RN-5 128 via PCell. Discovery signal configuration information may include, for example, discovery timing and sequence identifier. This discovery signal configuration information can be transmitted in the configuration message.

[0032] Upon receiving this configuration message, the RN-5 128 can begin sending one or more discovery signals based on the discovery signal configuration information. This allows other relay nodes in camping mode to detect the RN-5 128 for additional mmWave connections.

[0033] In some embodiments, all relay nodes in coverage area 108 can report the received power or quality of detected discovery signals to eNB 104. These reports can be transmitted via corresponding PCell or SCell. In some embodiments, reports can be made by relay nodes based on periodic reporting events (e.g., periodic reporting timers expiring) or based on requests from eNB 104.

[0034] The eNB 104 can use information fed back from each relay node to reconfigure the mmWave SCell and discovery signal configuration for each relay node, update the backhaul link topology, or enable advanced cooperative operations.

[0035] The described embodiments enable the establishment of self-organizing, multi-hop mmWave backhaul links with automatic beam alignment by measuring directional discovery signals. Dynamic path switching and cooperative transmission for the backhaul link can be entirely controlled by the eNB 104, which possesses complete knowledge of the mmWave links in the network. Furthermore, the configuration or reconfiguration of the backhaul link can be performed through an established PCell, which can be more robust than an mmWave-based SCell. This ensures a better user experience.

[0036] Discovery signals sent by relay nodes can be executed on a periodic basis. These discovery signals can be implemented using signal sequences with desired autocorrelation properties (e.g., the Zadoff-Chu sequence in LTE systems) to assist in the detection of discovery signals.

[0037] Given transmit power limits and target beamforming gain, a relay node can transmit one or more parallel radio frequency (RF) beams simultaneously. Let n b ∈{1, 2, ..., N b Defines the number of parallel RF beams supported by the relay node. A relay node can use different sequence signatures to transmit n signals using the same time and frequency resources. b These are detection signals, and the signatures can be based on sequence identifiers and beam directions.

[0038] Figure 2 Three discovery signals, according to some embodiments, can be simultaneously transmitted by a relay node in a corresponding RF beam. Each discovery signal can be simultaneously described using its own signal sequence signature. Figure 2 The three detection signals are shown as (a), (b), and (c). Figure 2 As shown, each of these detection signals can include n D Discovery clusters are transmitted periodically at the same period (e.g., 80ms, 160ms, or longer). Each discovery cluster may include n0 discovery moments, where each discovery moment consists of N transmission time intervals (TTIs). One or more TTIs may be reserved solely for transmission (Tx) to send a discovery signal.

[0039] The discovery signal in each discovery moment of the cluster can be transmitted in different beam directions, so beam scanning can be performed by the same physical RF beamformer.

[0040] In one embodiment, a relay node, such as the RN-5 128, may include three antenna arrays, each of which can be driven by its own RF beamformer and can serve a 120° sector. Assuming n0 = 8, each sector can be spanned by eight beam directions with a beam direction spacing of 15° (one per discovery time period) within a discovery cluster time period. If a TTI is 100 μs and a discovery time period comprises 10 TTIs, a discovery signal can be transmitted on a sector in 8 ms.

[0041] To support multi-hop backhaul links, each relay node can receive and track discovery signals from upstream relay nodes and send its own discovery signals to downstream relay nodes or the UEs it serves. To avoid the need for simultaneous transmission and reception (and therefore, a full-duplex transmission structure), relay nodes at different hops can send discovery signals at different times.

[0042] To facilitate the transmission of detection signals at different times, it is possible to, for example... Figure 2 As shown in (d), p discovery zones are defined at the start of each discovery cycle. Each discovery zone may include K discovery opportunities. Different relay nodes may have different discovery signal capabilities, and therefore, different numbers of discovery opportunities are required to send discovery signals in the discovery cluster. Therefore, K can be chosen as the maximum expected number of discovery opportunities required. In most instances, K can be greater than n0, but K can also be equal to n0.

[0043] Refer again Figure 1 The eNB 104 can use its mmWave radio to transmit a discovery signal in the 0-hop discovery zone; RN-1 112 and RN-2 116 can transmit discovery signals in the 1-hop and 2-hop discovery zones, respectively; and RN-3 120 and RN-4 124 can transmit discovery signals in the 3-hop discovery zone.

[0044] In other embodiments, only two discovery zones may be used. The first discovery zone may be used for relay nodes that send discovery signals at even-numbered hop positions relative to the anchor eNB, such as eNB 104 and RN-2 116. The second discovery zone may be used for relay nodes that send discovery signals at odd-numbered hop positions relative to the anchor eNB, such as RN-1112, RN-3 120, and RN-4 124.

[0045] In some embodiments, by ensuring that the frame boundaries and discovery period boundaries of the SCell are aligned with the corresponding boundaries in the PCell, the relay node's discovery signal can be synchronized with the PCell signal. This allows the PCell to assist the relay node in discovery. This can be done periodically by the relay node or eNB 104 performing boundary alignment processing, or when it is determined that the boundaries have become misaligned.

[0046] Figures 3-5 Stages 1-3 of the mmWave backhaul link establishment process according to some embodiments are shown. Specifically, Figure 3 The downlink alignment (or “first”) phase 300 of the mmWave backhaul link establishment process according to some embodiments is shown; Figure 4 The discovery signal configuration (or "second") phase 400 of the mmWave backhaul link establishment process according to some embodiments is shown; Figure 5 An uplink beam alignment (or "third") phase 500 of the mmWave backhaul link establishment process is illustrated according to some embodiments. The various phases of the mmWave backhaul link establishment process can be initiated after the anchor node (e.g., eNB 104) establishes an RRC connection with the target relay node (e.g., RN-5 128).

[0047] Although stages 300, 400, and 500 are referred to as the first, second, and third stages, this does not mean that these stages occur sequentially in all examples. For example, in some embodiments, some of these stages may be performed independently of the others; for instance, the third stage may be executed more frequently than the first and second stages.

[0048] First refer to Figure 3 In the downlink alignment phase 300 shown, at point 304, eNB 104 can send a discovery signal message to RN-5 128. This discovery signal message can include configuration information for mmWave discovery signals, which may be sent by other relay nodes in coverage area 108. Due to corresponding PCell connections with the respective other relay nodes in coverage area 108, eNB 104 can have knowledge about the discovery signal configurations of these other relay nodes. Configuration information may include, for example, the start time location of each discovery cluster, the number of discovery moments in each discovery cluster, and the periodicity of the discovery clusters for mmWave discovery signals sent by the respective other relay nodes in coverage area 108. The discovery signal message may also include a request for measurement information corresponding to the mmWave discovery signals, which may be explicit or implicit.

[0049] At 308, the RN-5 128 uses configuration information from the discovery signal message to measure metrics of the mmWave discovery signal. The RN-5 128 can activate its mmWave receiver during the time periods during which the mmWave discovery signal may occur, and measure various metrics of the discovery signal when it is detected. In some embodiments, the measured metrics may include, but are not limited to, Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ). The detected mmWave discovery signal can be identified by a discovery timing index and a sequence identifier in the discovery cluster. The sequence identifier can identify which of a plurality of parallel discovery signals transmitted by the relay node is being measured, and the discovery timing index can identify the specific beam used to transmit the detected discovery signal.

[0050] RN-5 128 can send a measurement report to eNB 104 at 312. Measurement report 312 may include a sequence and beam identifier for each detected discovery signal, as well as an indication of the measured metric. In some embodiments, if the measured metric corresponding to a discovery signal exceeds a threshold, RN-5 128 may report only information about that discovery signal. This threshold may be pre-configured by eNB 104, determined by RN-5 128, or otherwise predetermined.

[0051] At 316, eNB 104 can select one or more relay nodes as corresponding mmWave SCells to serve RN-5 128. The relay nodes selected to provide mmWave SCells for RN-5 128 can be selected based on measured metrics of their discovery signals. In the described embodiment, the selected relay node providing mmWave SCells for RN-5 128 could be RN-3 120. In some embodiments, such as the one currently described, only one mmWave SCell can be selected. In other embodiments (some of which are described in more detail below), more than one relay node / mmWave SCell can be selected.

[0052] At 320, eNB 104 can send an RRC connection reconfiguration message. The RRC connection reconfiguration message may include information used to configure the mmWave SCell provided by RN-3 120. In some embodiments, the information may include the defined transmit / receive TTI configuration of the mmWave SCell provided by RN-3 120. The TTI configuration of the mmWave SCell provided by RN-3 120 can indicate the TTI for RN-3 120 to transmit and / or receive information.

[0053] As described above, the RN-5 128 can use mmWave Radio Access Technology (RAT) for both access and backhaul links. Therefore, in some embodiments, time-domain duplexing for mmWave relay node Tx / Rx can be employed. This allows for complementary Tx / Rx TTI configurations for adjacent relay nodes with established communication paths. For example, the Tx TTI of the RN-3 120 can correspond to... Figure 1 The RN-5 128 uses the Rx TTI. This complementary Tx / Rx TTI configuration allows the same air interface to be used for both backhaul and access links. For example, the mmWave-Uu interface can be used for both backhaul and access links, unlike LTE in-band relays where the Uu and Un interfaces can be used for access and backhaul links, respectively.

[0054] At position 324, RN-5 128 can send an RRC connection reconfiguration complete message to eNB 104 to indicate that the mmWave SCell has been successfully set up.

[0055] After 324, at 328, RN-5 128 can begin monitoring the channels in both the PCell and SCell that are scheduling data in the corresponding cell.

[0056] At 332, eNB 104 can send an RRC context setting message to RN-3 120. The RRC context setting message can include the RRC context in RN-5 128, including, for example, the identifier of RN-5 128 and its preferred beam direction. The preferred beam direction can be indicated by identifying the discovery timing (using, for example, a beam ID or discovery timing index) or the sector (using, for example, a sequence ID).

[0057] At position 336, RN-3 120 can send a context setting response to eNB 104. The context setting response provides an indication that the context of RN-5 128 has been successfully received by RN-3 120.

[0058] After 336, RN-3 120 can use preferred sectors and beam directions to schedule and forward data to RN-5 128 via SCell.

[0059] Although Phase 300 is described as configuring one SCell for RN-5 128, other embodiments may configure more than one SCell. For example, in some embodiments, both RN-3 120 and RN-4 124 can be configured by eNB 104 to provide SCells for RN-5 128 to achieve dynamic path switching. Subsequently, in a specific backhaul link TTI, based on a routing decision made by eNB 104 according to a specific standard, backhaul link packets to RN-5 128 can be routed from either RN-3 120 or RN-4 124. By doing so, dynamic path switching or routing can be achieved without backhaul link reconfiguration, and such dynamic path switching or routing can also be transparent to the destination / relay node (e.g., RN-5 128). Furthermore, it can also facilitate cooperative transmit / receive operations on the backhaul link when both RN-3 120 and RN-4 124 are configured as upstream relay nodes for RN-5 128. Cooperative transmission can occur in the downlink when, for example, both RN-3 120 and RN-4 124 send the same information to RN-5 128. Cooperative reception can occur in the uplink when, for example, RN-5 128 sends information to both RN-3 120 and RN-4 124.

[0060] In some embodiments, the discovery signal configuration phase 400 may occur after the downlink alignment phase 300. The discovery signal configuration phase 400 may be used to configure the discovery signal to be transmitted by the RN-5 128.

[0061] At position 404, the RN-5 128 sends a discovery signal capability message to the eNB 104. This discovery signal capability message may include an indication of the number of parallel and sequential mmWave discovery signals that the RN-5 128 is capable of sending.

[0062] At 408, eNB 104 can send a discovery signal capability confirmation message to RN-5 128. In some embodiments, the discovery signal capability confirmation message may include an indication of the number of hops associated with RN-5 128. This hop number can be used by RN-5 128 to determine in which discovery cluster during the discovery cycle RN-5 128 will send its discovery signal. For example, the discovery signal capability confirmation message may indicate that RN-5 128 is associated with 3 hops. Therefore, RN-5 128 may send its discovery signal in a discovery cluster located in a 3-hop discovery area.

[0063] At position 412, the RN-5 128 can send a discovery signal acknowledgment response to the eNB 104. This discovery signal acknowledgment response indicates that the RN-5 128 has successfully received the configuration information sent at position 408.

[0064] At position 416, the RN-5 128 can begin transmitting a discovery signal. The discovery signal transmitted by the RN-5 128 can be used by other relay nodes for uplink beam alignment (as referenced below). Figure 5 (detailed description) The possible backhaul route is identified by the newly installed relay node or by the UE that will use mmWave RAT as the user access mechanism.

[0065] In some embodiments, the uplink beam alignment phase 500 may occur after the discovery signal configuration phase 400. The uplink beam alignment phase 500 may be used to improve the efficiency of uplink communication transmitted from RN-5 128 to RN-3 120.

[0066] At 508, eNB 104 can send a measurement request to RN-3 120 to request measurement information corresponding to the discovery signal of RN-5 128.

[0067] At position 512, RN-3 can measure the detection signal transmitted by RN-5 128 and record the various metrics described above. The measured metrics may include, but are limited to, RSRP and RSRQ.

[0068] At position 516, RN-3 120 can send a measurement report to eNB 104. This measurement report may include measurement metrics and corresponding sequence and beam identifiers.

[0069] At 520, eNB 104 can select the uplink transmission beam direction based on the measurement report. The uplink transmission beam direction can be the most efficient direction for transmitting uplink information from RN-5 128 to RN-3 120 via multi-hop backhaul, as determined by the eNB.

[0070] At 524, eNB 104 can send an RRC connection reconfiguration message to RN-128. This RRC connection reconfiguration message may include an indication of the transmit beam direction that RN-5 128 should use to send information to RN-3 120.

[0071] At position 528, RN-5 128 can send an RRC connection reconfiguration complete message to eNB 104. This RRC connection reconfiguration complete message confirms that RN-5 128 has received and successfully processed the information in the RRC connection reconfiguration message.

[0072] At 532, RN-5 128 can use the selected transmit beam direction indicated in the RRC connection reconfiguration message to send uplink information to RN-3 120.

[0073] Such discovery measurements as those in 512 can be performed periodically using measurement results that are regularly reported to the eNB 104. This enables beam tracking to ensure that uplink information is transmitted efficiently. Similar processing can be implemented for downlink transmissions.

[0074] In some instances, multi-hop backhaul link paths can be modified. For example, for load balancing or improved power savings. Figure 1 The eNB 104 can decide to switch the backhaul link of RN-5 128 from P1 to P2. To do this, the eNB 104 can change the SCell configuration for RN-5 128 from RN-3 120 to RN-4 124. In this case, Phase 1 300 and Phase 3 500 can be performed by replacing RN-3 120 with RN-4 124 to achieve downlink and uplink beam alignment for the new backhaul link L6.

[0075] Figure 6 A computing device 600 according to various embodiments is illustrated, which may represent a relay node or eNB. In embodiments, the computing device 600 may include a control circuitry system 604 coupled to a first radio circuitry system 608 and a second radio circuitry system 612. The first radio circuitry system 608 and the second radio circuitry system 612 may be coupled to one or more antennas 616.

[0076] The first radio circuit system 608 may include a radio transceiver that operates in a mobile broadband spectrum. For example, the first radio circuit system 608 may include a radio transmit / receive circuit system configured to transmit / receive RF signals at frequencies less than about 6 GHz. The first radio circuit system 608 may include one or more beamformers 610, which, in conjunction with one or more antennas 616, can provide directional and potentially dynamically configurable reception / transmission of RF signals.

[0077] The second radio circuit system 612 may include a radio transceiver that operates in the mmWave spectrum. For example, the second radio circuit system 612 may include a radio transmit / receive circuit system configured to transmit / receive RF signals at frequencies greater than 6 GHz (in some embodiments, between approximately 30 GHz and 300 GHz). The second radio circuit system 612 may include one or more beamformers 614, which, in conjunction with one or more antennas 616, can provide directional and potentially dynamically configurable reception / transmission of RF signals.

[0078] Referring again to the above... Figure 2 In the discussed example, the second radio circuit system 612 may include three beamformers 614. Each beamformer 614 can serve a 120° sector. To transmit an mmWave discovery signal in the corresponding sector, each beamformer 614 is capable of operating at a 15° beam direction interval. Thus, eight discovery signals can be transmitted at eight discovery times in a discovery cluster, each of the eight discovery signals being transmitted in a different beam direction. Other embodiments may include a second radio circuit system 612 with additional discovery signal capabilities. As mentioned above regarding... Figure 4 As described, indications of these discovery signaling capabilities can be transmitted to the eNB in ​​message 404.

[0079] Control circuitry system 604 can control the operation of first radio circuitry system 608 and second radio circuitry system 612 to perform operations similar to those described elsewhere in this disclosure. For example, control circuitry system 604 can be combined with first radio circuitry system 608 and second radio circuitry system 612 to perform the operations of eNB 104, RN-5 128, or RN-3120 described above in phases 1-3 of the mmWave backhaul link establishment process. Typically, control circuitry system 604 can control first radio circuitry system 608 and second radio circuitry system 612 to send / receive messages as described herein on suitable radio interfaces. Control circuitry system 604 can perform higher-level operations, such as generating messages to be sent, processing received messages, selecting relay nodes providing mmWave SCells, scheduling and transmitting data, etc.

[0080] The embodiments described herein can be implemented as a system using any appropriately configured hardware and / or software. Figure 7 An example system for one embodiment is shown, which includes a radio frequency (RF) circuit system 704, a baseband circuit system 708, an application circuit system 712, a memory / storage device 716, and an interface circuit system 720, which are coupled to each other at least as shown.

[0081] Application circuit system 712 may include circuit systems such as, but not limited to, one or more single-core or multi-core processors. The processors (one or more) may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). The processors may be coupled to memory / memory device 716 and configured to execute instructions stored in memory / memory device 716 to enable various applications and / or operating systems to run on the system.

[0082] The baseband circuit system 708 may include a circuit system such as, but not limited to, one or more single-core or multi-core processors. One or more processors may include a baseband processor. The baseband circuit system 708 can handle various radio control functions that enable communication with one or more radio networks via the RF circuit system 704. Radio control functions may include, but are not limited to, signal modulation, encoding, decoding, radio frequency shifting, etc. In some embodiments, the baseband circuit system can provide communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuit system 708 may support communication with the Evolved Universal Terrestrial Radio Access Network (EUTRAN) and / or other Wireless Metropolitan Area Networks (WMAN), Wireless Local Area Networks (WLAN), and Wireless Personal Area Networks (WPAN). The following embodiment may be referred to as a multimode baseband circuit system: in this embodiment, the baseband circuit system 708 is configured to support radio communication with more than one radio protocol.

[0083] In various embodiments, the baseband circuit system 708 may include circuitry that operates on signals that are not strictly considered to be in the baseband frequency. For example, in some embodiments, the baseband circuit system 708 may include circuitry that operates on signals having an intermediate frequency between the baseband frequency and the radio frequency.

[0084] RF circuitry system 704 enables communication with wireless networks via modulated electromagnetic radiation and non-solid-state media. In various embodiments, RF circuitry system 704 may include switches, filters, amplifiers, etc., to facilitate communication with wireless networks.

[0085] In various embodiments, the RF circuitry system 704 may include circuitry that operates for signals that are not strictly considered to be at the radio frequency. For example, in some embodiments, the RF circuitry system may include circuitry that operates for signals having an intermediate frequency between the baseband frequency and the radio frequency.

[0086] In various embodiments, the radio circuitry and control circuitry discussed herein with respect to a relay node or eNB may be embodied, in whole or in part, in one or more of the RF circuitry 704, the baseband circuitry 708, and / or the application circuitry 712.

[0087] In some embodiments, some or all of the constituent components of the baseband circuit system 708, the application circuit system 712, and / or the memory / storage device 716 may be implemented together on a system-on-a-chip (SOC).

[0088] The memory / storage device 716 can be used to load and store, for example, data and / or instructions for a system. For one embodiment, the memory / storage device 716 may include any combination of suitable volatile memory (e.g., dynamic random access memory (DRAM)) and / or non-volatile memory (e.g., flash memory).

[0089] In various embodiments, the interface circuitry system 720 may include one or more user interfaces designed to enable a user to interact with the system and / or peripheral component interfaces designed to enable peripheral components to interact with the system.

[0090] In various embodiments, the interface circuitry 720 may be a network interface having circuitry for communicating with one or more other network technologies. For example, the interface circuitry 720 may be able to communicate via Ethernet or other computer networking technologies using various physical media interfaces (such as, but not limited to, coaxial, twisted-pair, or fiber optic media interfaces).

[0091] In various embodiments, the system may have more or fewer components, and / or different architectures.

[0092] Below are some unrestricted examples.

[0093] Example 1 includes one or more computer-readable media having instructions that, when executed, cause the eNB to: establish a primary cell (PCell) in the mobile broadband spectrum to communicate with a first relay node; transmit a discovery signal message via the PCell, the discovery signal message including configuration information for a millimeter-wave (mmWave) discovery signal to be transmitted by one or more other relay nodes and a request for measurement information corresponding to the mmWave discovery signal; receive a measurement report from the first relay node via the PCell, the measurement report including measurement information corresponding to the mmWave discovery signal; and select a second relay node based on the measurement report to provide a mmWave secondary cell (SCell) for the first relay node.

[0094] Example 2 includes one or more computer-readable media of Example 1, wherein, when executed, these instructions also cause the eNB to: send a radio resource control message to the first relay node to configure the mmWave SCell.

[0095] Example 3 includes one or more computer-readable media of Example 1, wherein the measurement report includes a sequence identifier and a beam identifier, and the instructions, when executed, also cause the eNB to: send the radio resource control (RRC) context of the first relay node to the second relay node, the context including the sequence identifier and the beam identifier.

[0096] Example 4 includes one or more computer-readable media of Example 1, wherein, when the instructions are executed, the eNB is also caused to: receive a discovery signal capability message from a first relay node, the discovery signal capability message including indications of parallel and sequential mmWave discovery signals that the first relay node is capable of transmitting.

[0097] Example 5 includes one or more computer-readable media of Example 4, wherein, when executed, these instructions also cause the eNB to: send a discovery signal capability confirmation to a first relay node, the discovery signal capability confirmation including an indication of a hop area in which the first relay node will send an mmWave discovery signal.

[0098] Example 6 includes one or more computer-readable media of any one of Examples 1-5, wherein when the instructions are executed, the eNB also causes the eNB to: send a request to a second relay node for measurement information corresponding to a discovery signal from a first relay node; receive a measurement report from the second relay node, the measurement report including a sequence identifier and a beam identifier; select a transmit beam direction for transmission from the first relay node to the second relay node; and send an indication of the transmit beam direction to the first relay node.

[0099] Example 7 includes one or more computer-readable media of Example 1, wherein the mmWave SCell is a first mmWave SCell, and these instructions, when executed, also cause the eNB to: select a third relay node based on a measurement report to provide a second mmWave SCell for the first relay node.

[0100] Example 8 includes an apparatus for providing user access to a cell, the apparatus comprising: a first radio circuit system communicating in a mobile broadband spectrum; a second radio circuit system communicating in a millimeter-wave (mmWave) spectrum; and a control circuit system coupled to the first and second radio circuit systems, the control circuit system: receiving, via the first radio circuit system, a discovery signal message from the eNB via a primary cell (PCell) provided by an enhanced node B (eNB), the discovery signal message including configuration information for an mmWave discovery signal to be transmitted by one or more relay nodes within the coverage area of ​​the eNB and a request for measurement information corresponding to the mmWave discovery signal; controlling the second radio circuit system to measure the mmWave discovery signal based on the configuration information; and transmitting a measurement report to the eNB via the first radio circuit system, the measurement report including the measurement information corresponding to the mmWave discovery signal.

[0101] Example 9 includes the apparatus of Example 8, wherein the control circuitry can also receive radio resource control messages via a first radio circuitry, the radio resource control messages including configuration information of mmWave SCell provided to the apparatus by one or more relay nodes.

[0102] Example 10 includes the apparatus of Example 9, wherein a control circuit system controls a first radio circuit system to monitor the control channel of PCell and controls a second radio circuit system to monitor the control channel of SCell.

[0103] Example 11 includes the apparatus of Example 9, wherein a control circuit system transmits discovery signal capability information via a first radio circuit system, the discovery signal capability information including the number of parallel and sequential mmWave discovery signals that a second radio circuit system is capable of transmitting.

[0104] Example 12 includes the apparatus of Example 11, wherein a control circuitry system receives a discovery signal capability confirmation from an eNB via a first radio circuitry system, the discovery signal capability confirmation including an indication of a hop zone in which the apparatus will transmit an mmWave discovery signal.

[0105] Example 13 includes an apparatus of any of Examples 8-12, wherein the second radio circuit system includes one or more radio frequency (RF) beamformers, and the second radio circuit system transmits mmWave discovery signals in one or more discovery clusters corresponding to the one or more RF beamformers respectively.

[0106] Example 14 includes the apparatus of Example 13, wherein one or more discovery clusters overlap in time.

[0107] Example 15 includes the apparatus of Example 13, wherein a first RF beamformer transmits a plurality of mmWave discovery signals at corresponding plurality of discovery times of a discovery cluster, wherein each of the plurality of mmWave discovery signals is transmitted in a different beam direction.

[0108] Example 16 includes the apparatus of Example 13, wherein one or more discovery clusters exist in a jump discovery area indicated by the eNB.

[0109] Example 17 includes an apparatus of any of Examples 8-16, wherein the control circuitry: receives an instruction regarding a transmit beam configuration via a first radio circuitry; and transmits uplink data via a second radio circuitry through SCell based on the transmit beam configuration.

[0110] Example 18 includes one or more computer-readable media with instructions that, when executed, cause a first relay node to: receive a radio resource control (RRC) context from an enhanced node B (eNB) via a primary cell (PCell) in the mobile broadband spectrum from a second relay node, the RRC context including indications about preferred sectors and beams; schedule and transmit data to the second relay node using the preferred sectors and beams and millimeter wave (mmWave) signals.

[0111] Example 19 includes one or more computer-readable media of Example 18, wherein, when executed, the instructions also cause the first relay node to: provide a secondary cell (SCell) for the second relay node; and transmit data via the SCell.

[0112] Example 20 includes one or more computer-readable media of Example 18 or 19, and these instructions, when executed, also cause a first relay node to: receive a measurement request from an eNB; measure an mmWave discovery signal from a second relay node based on the measurement request; and send a measurement report to the eNB, the measurement report including indications about the sequence and beam.

[0113] Example 21 includes one or more computer-readable media of Example 20, wherein the indications regarding the sequence and beam include a sequence identifier and a beam identifier.

[0114] Example 22 includes an apparatus comprising: a first radio circuit system; a second radio circuit system for communication using millimeter-wave (mmWave) spectrum; and a control circuit system that: controls the first radio circuit system to provide a primary cell (PCell) in mobile broadband spectrum for communication with a first relay node; transmits a discovery signal message via the PCell, the discovery signal message including configuration information for an mmWave discovery signal to be transmitted by one or more other relay nodes, and a request for measurement information corresponding to the mmWave discovery signal; receives a measurement report from the first relay node via the PCell, the measurement report including measurement information corresponding to the mmWave discovery signal; and selects a second relay node based on the measurement report to provide an mmWave secondary cell (SCell) for the first relay node.

[0115] Example 23 includes the apparatus of Example 22, wherein the control circuitry further causes the first radio circuitry to send a radio resource control message to the first relay node to configure the mmWave SCell.

[0116] Example 24 includes the apparatus of Example 22, wherein the measurement report includes a sequence identifier and a beam identifier, and the control circuitry further controls a first radio circuitry to transmit a radio resource control (RRC) context of the first relay node to the second relay node, the RRC context including the sequence identifier and the beam identifier.

[0117] Example 25 includes the apparatus of Example 22, wherein a second radio circuit system receives a discovery signal capability message from a first relay node, the message including an indication of the number of parallel and sequential mmWave discovery signals that the first relay node is capable of transmitting.

[0118] Example 26 includes the apparatus of Example 25, wherein the control circuitry system further controls the first radio circuitry system to: send a discovery signal capability confirmation to a first relay node, the discovery signal capability confirmation including an indication of a hop area in which the first relay node will send an mmWave discovery signal.

[0119] Example 27 includes the apparatus of Example 22, wherein: a second radio circuit system sends a request to a second relay node for measurement information corresponding to a discovery signal of a first relay node, and receives a measurement report from the second relay node, the measurement report including a sequence identifier and a beam identifier; a control circuit system selects a transmit beam direction for transmission from the first relay node to the second relay node, and controls the second radio circuit system to send an indication of the transmit beam direction to the first relay node.

[0120] Example 28 includes the apparatus of Example 22, wherein the mmWave SCell is a first mmWave SCell, and the control circuitry selects a third relay node based on a measurement report to provide a second mmWave for the first relay node.

[0121] Example 29 includes a method of operating a relay node in a cellular network, the method comprising: authenticating the relay node in the cellular network by sending an authentication message to an anchor evolved Node B (eNB) via a Radio Resource Control (RRC) connection, the relay node providing millimeter-wave (mmWave) connectivity; processing a response received from the anchor eNB in ​​relation to the authentication message; and processing the RRC message received from the anchor eNB after receiving a response in the cellular spectrum below 6 GHz.

[0122] Example 30 includes the method of Example 29, wherein the anchor eNB provides the primary cell (PCell) of the cellular network to support communication with the relay node.

[0123] Example 31 includes the method of Example 29, wherein the authentication message is sent to the Mobility Management Entity (MME) of the cellular network.

[0124] Example 32 includes the method of Example 29, wherein the RRC message is scheduled in the Physical Downlink Control Channel (PDCCH) or the Enhanced PDCCH (e-PDCCH).

[0125] Example 33 includes the method of any one of Examples 29-32, wherein the relay node is a first relay node, the mmWave cell is a first mmWave cell, and the method further includes: processing an mmWave discovery signal received from a second relay node providing a second mmWave cell; measuring the received power or received quality of the mmWave discovery signal; and reporting an indication to the anchor eNB regarding the measurement of the received power or received quality.

[0126] Example 34 includes the method of Example 33, and further includes: reporting the indication based on periodic reporting events or requests from the anchor eNB.

[0127] Example 35 includes the method of Example 33, and further includes: processing a discovery signal message from the anchor eNB; and detecting an mmWave discovery signal based on the discovery signal message.

[0128] Example 36 includes a method comprising: receiving a discovery signal message from an eNB via a primary cell (PCell) provided by an enhanced node B (eNB), the discovery signal message including configuration information of an mmWave discovery signal to be transmitted by one or more relay nodes in the coverage area of ​​the eNB and a request for measurement information corresponding to the mmWave discovery signal; measuring the mmWave discovery signal based on the configuration information; and sending a measurement report to the eNB, the measurement report including the measurement information corresponding to the mmWave discovery signal.

[0129] Example 37 includes the method of Example 36, and further includes: receiving a radio resource control message, the radio resource control message including mmWave SCell configuration information provided by a relay node among the one or more relay nodes.

[0130] Example 38 includes the method of Example 36, and further includes: monitoring the control channels of PCell and SCell.

[0131] Example 39 includes the method of Example 36, and further includes: sending discovery signaling capability information to the eNB, the discovery signaling capability information including the number of parallel and sequential mmWave discovery signals that the relay node is capable of transmitting.

[0132] Example 40 includes the method of Example 39, further comprising: receiving a discovery signal capability confirmation from an eNB, the discovery signal capability confirmation including an indication of a hop zone in which the device will transmit an mmWave signal.

[0133] Example 41 includes the method of any of Examples 36-39, further comprising: transmitting an mmWave discovery signal in one or more discovery clusters, each of the one or more discovery clusters corresponding to one or more radio frequency beamformers.

[0134] Example 42 includes the method of Example 41, wherein one or more discovery clusters overlap in time.

[0135] Example 43 includes the method of Example 41, wherein a first RF beamformer transmits multiple mmWave discovery signals at corresponding multiple discovery times of a discovery cluster, wherein each of the multiple mmWave discovery signals is transmitted in a different beam direction.

[0136] Example 44 includes the method of Example 41, wherein one or more discovery clusters exist in a jump discovery zone indicated by the eNB.

[0137] Example 45 includes the method of any of Examples 36-44, further comprising: receiving an indication of a transmit beam configuration; and transmitting downlink data via SCell based on the transmit beam configuration.

[0138] Example 46 includes a method of operating a first relay node, the method comprising: receiving a radio resource control (RRC) context of a second relay node from an evolved Node B (eNB) via a primary cell (PCell) in the mobile broadband spectrum, the RRC context including indications of preferred sectors and beams; scheduling and transmitting data to the second relay node using the preferred sectors and beams and millimeter wave (mmWave) signals.

[0139] Example 47 includes the method of Example 46, and further includes providing a secondary cell (SCell) for the second relay node; and transmitting data via the SCell.

[0140] Example 48 includes the method of Example 46 or 47, and further includes: receiving a measurement request from the eNB; measuring an mmWave discovery signal from a second relay node based on the measurement request; and sending a measurement report to the eNB, the measurement report including indications about the sequence and beam.

[0141] Example 49 includes the method of Example 48, wherein the indications regarding the sequence and beam include a sequence identifier and a beam identifier.

[0142] Example 50 includes a method for operating a relay node, comprising: establishing a Radio Resource Control (RRC) connection with an evolved Node B (eNB) using Long Term Evolution (LTE) User Equipment (UE) functionality, the eNB acting as the primary cell (PCell) for the relay node; performing mmWave small cell node authentication to the Mobility Management Entity (MME) via the eNB; monitoring Physical Downlink Control Channel (PDCCH) or Enhanced PDCCH (E-PDCCH) transmitted from the eNB in ​​cellular spectrum below 6 GHz; and demodulating and decoding RRC signaling transmitted from the eNB in ​​legacy cellular spectrum below 6 GHz.

[0143] Example 51 includes a method for operating an evolved Node B (eNB), comprising: acting as the primary cell (PCell) for a relay node; configuring a receive discovery signal to the relay node; configuring a millimeter wave (mmWave) secondary cell for the relay node; and routing backhaul link traffic to the relay node.

[0144] Example 52 includes a method comprising: a relay node in a cellular network sending an authentication message, which is associated with millimeter-wave (mmWave) small cell node authentication, to an anchor evolved Node B (eNB) in the cellular network over a Radio Resource Control (RRC) connection;

[0145] The relay node receives a response related to the authentication message from the anchor eNB; and after receiving the response related to the authentication message, the relay node receives a Radio Resource Control (RRC) message in the cellular spectrum below 6 GHz from the anchor eNB.

[0146] Example 53 includes a method comprising: sending an indication from an evolved Node B (eNB) in a cellular network to a relay node regarding the configuration for receiving discovery signals, the eNB acting as the primary cell (PCell) for the relay node and configured to transmit millimeter wave (mmWaVe) signals; sending an indication from the eNB to the relay node regarding the configuration for the mmWaVe secondary cell (SCell); and routing backhaul link traffic from the eNB to the relay node.

[0147] Example 54 includes a method comprising: receiving, by a first relay node in a cellular network, a message from an evolved Node B (eNB) including a preferred sector identifier (ID) or beamdirection ID for downlink (DL) traffic to a second relay node; transmitting the DL traffic to the second relay node based on the preferred sector ID or beamdirection ID; receiving, by the first relay node in the cellular network, a discovery signal associated with millimeter-wave (mmWave) transmission of the second relay node from the second relay node in the cellular network; identifying, by the first relay node, the discovery signal reception power or discovery signal reception quality associated with the discovery signal; and transmitting, by the first relay node, an indication to the eNB in ​​the cellular network regarding the identified discovery signal reception power or discovery signal reception quality.

[0148] Example 55 includes one or more computer-readable media having instructions that, when executed, cause the device to perform any of the methods in Examples 29-54.

[0149] Example 56 includes an apparatus that includes means for performing any of the methods in Examples 29-54.

[0150] The description of the implementations shown herein (including the description in the abstract) is not intended to be exhaustive or to limit this disclosure to the precise forms disclosed. Although specific implementations and examples are described herein for illustrative purposes, various equivalent modifications are possible within the scope of this disclosure, as will be appreciated by those skilled in the art. These modifications can be made to this disclosure based on the specific embodiments described above.

Claims

1. An apparatus for a user to access a cell, the apparatus comprising: One or more processors, said one or more processors being communicatively coupled to a baseband circuitry system, said baseband circuitry system being configured to: The discovery signal message is received from the AN by the primary cell PCell provided by the anchor node AN. The discovery signal message includes configuration information of mmWave discovery signals to be sent by one or more relay nodes within the coverage area of ​​the AN and a request for measurement information corresponding to the mmWave discovery signal. Based on the configuration information included in the discovery signal message received from the AN, the mmWave discovery signal to be sent by one or more relay nodes is measured; as well as A measurement report is sent to the AN, the measurement report including measurement information corresponding to the mmWave discovery signal.

2. The apparatus of claim 1, wherein the baseband circuit system is further configured to: Receive a reconfiguration message for communicating with the first relay node among the one or more relay nodes.

3. The apparatus of claim 1, wherein the baseband circuit system is further configured to: The device receives a radio resource control message, which includes configuration information of an mmWave cell to be provided to the device by one or more relay nodes.

4. The apparatus according to any one of claims 1-3, wherein the baseband circuitry is further configured to configure one or more radio frequency (RF) beamformers to transmit mmWave discovery signals in one or more discovery clusters corresponding to the one or more RF beamformers, respectively.

5. The apparatus of claim 4, wherein the one or more discovery clusters overlap in time.

6. The apparatus of claim 4, wherein the baseband circuitry further configures a first RF beamformer of the one or more RF beamformers to transmit a plurality of mmWave discovery signals at corresponding discovery times in a discovery cluster, wherein each of the plurality of mmWave discovery signals is transmitted in a different beam direction.

7. The apparatus of claim 1, wherein the configuration information included in the discovery signal message includes a discovery timing and a sequence identifier, and further includes configuration information for a discovery cluster for the mmWave discovery signal, wherein the configuration information for the discovery cluster includes: The start time position of each discovery cluster in the discovery cluster; The number of discovery opportunities for each discovery cluster in the discovery cluster; as well as The periodicity of the discovered cluster.

8. The apparatus of claim 7, wherein the measurement report includes a sequence identifier, a beam identifier, and an indication of the measured metric for each detected mmWave discovery signal, and wherein the detected mmWave discovery signal is identified by a sequence identifier within the discovery cluster and a discovery timing index, the sequence identifier identifying which of a plurality of parallel discovery signals transmitted by a relay node in one or more relay nodes was measured by the apparatus, and the discovery timing index identifying the specific beam used to transmit the detected mmWave discovery signal.

9. The apparatus of claim 1 or 8, wherein the baseband circuitry is further configured to transmit discovery signal capability information to the AN via the PCell, the discovery signal capability information including an indication of the number of parallel and continuous mmWave discovery signals that the apparatus is capable of transmitting.

10. The apparatus of claim 8, wherein the signal sequence for the mmWave discovery signal transmitted by each of the one or more relay nodes identifies the corresponding relay node, and wherein within each discovery cluster, the mmWave discovery signal is transmitted along different beam directions at a corresponding discovery timing.

11. An anchor node AN, comprising: One or more processors, said one or more processors being communicatively coupled to a baseband circuitry system, said baseband circuitry system being configured to: Discovery signal messages are sent by the primary cell PCell provided by the anchor node AN. The discovery signal messages include configuration information for mmWave discovery signals to be sent by one or more relay nodes within the coverage area of ​​the AN, as well as a request for measurement information corresponding to the mmWave discovery signals. as well as Receive a measurement report from the first relay node, the measurement report including measurement information corresponding to the mmWave discovery signal.

12. The AN of claim 11, wherein the baseband circuit system is further configured to: Based on the measurement report, a second relay node is selected to provide mmWave cells for the first relay node.

13. The AN according to any one of claims 11-12, wherein the baseband circuit system is further configured to: Send a radio resource control message to the first relay node to configure the mmWave cell.

14. The AN according to any one of claims 11-12, wherein the mmWave discovery signal in the mmWave discovery signal is identified by a sequence identifier.

15. The AN according to any one of claims 11-12, wherein the beam direction is identified by the discovery timing included in the discovery cluster of the mmWave discovery signal.

16. The AN according to any one of claims 11-12, wherein the measurement report includes a sequence identifier and a beam identifier, and the baseband circuitry is further configured to: Send the radio resource control message context of the first relay node, the radio resource control message context including the sequence identifier and the beam identifier.

17. The AN according to any one of claims 11-12, wherein the baseband circuitry is further configured to receive a discovery signal capability message from the first relay node, the discovery signal capability message including an indication of parallel and sequential mmWave discovery signals that the first relay node is capable of sending.

18. A method for a user to access a cell, the method comprising: The discovery signal message is received from the AN by the primary cell PCell provided by the anchor node AN. The discovery signal message includes configuration information of mmWave discovery signals to be sent by one or more relay nodes within the coverage area of ​​the AN and a request for measurement information corresponding to the mmWave discovery signal. Based on the configuration information included in the discovery signal message received from the AN, the mmWave discovery signal to be sent by one or more relay nodes is measured; as well as A measurement report is sent to the AN, the measurement report including measurement information corresponding to the mmWave discovery signal.

19. The method of claim 18, further comprising: Receive a reconfiguration message for communicating with the first relay node among the one or more relay nodes.

20. The method according to any one of claims 18-19, further comprising configuring one or more radio frequency (RF) beamformers to transmit mmWave discovery signals in one or more discovery clusters corresponding to the one or more RF beamformers respectively, and the one or more discovery clusters being present in a hop discovery region indicated by the AN.

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