Flow control for uplink traffic in integrated access and backhaul networks

Abstract

The present disclosure generally relates to flow control for uplink traffic in integrated access and backhaul networks. Systems and methods provide flow control for uplink traffic in an integrated access and backhaul network. The first relay node determines that its uplink buffer has reached an occupancy level above a predetermined level. In response, the first relay node transmits a message indicating a buffer occupancy status of the uplink buffer of the first relay node to a second relay node associated with the first relay node.

Description

[0001] This application is a divisional application of the application with international application number PCT / US2019 / 045772, international application date August 8, 2019, entry into the Chinese national phase date February 4, 2021, national application number 201980052029.5, and invention name “Flow control for uplink traffic in integrated access and backhaul networks”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 716,447, filed on August 9, 2018, which is hereby incorporated by reference in its entirety. Background Art

[0004] Wireless mobile communication technology uses various standards and protocols to transmit data between base stations and wireless mobile devices. Wireless communication system standards and protocols may include the third generation partnership project (3GPP) long term evolution (LTE); the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard, which is often referred to as the Worldwide Interoperability for Microwave Access (WiMAX) by industry organizations; and the IEEE 802.11 standard for wireless local area networks (WLANs), which is often referred to as Wi-Fi by industry organizations. In the 3GPP radio access network (RAN) in the LTE system, the base station may include a RAN node such as an evolved universal terrestrial radio access network (E-UTRAN) node B (also often referred to as an evolved node B, enhanced node B, eNodeB or eNB) and / or a radio network controller (RNC) in the E-UTRAN, which communicates with a wireless communication device called a user equipment (UE). In the fifth generation (5G) wireless RAN, the RAN node may include a 5G node, a new radio (NR) node or a gNodeB (gNB). BRIEF DESCRIPTION OF THE DRAWINGS

[0005] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the drawing number that first introduces the element.

[0006] Figure 1 An exemplary integrated access and backhaul (IAB) network according to one embodiment is schematically illustrated.

[0007] Figure 2 An IAB node uplink buffer according to one embodiment is schematically illustrated.

[0008] Figure 3 An exemplary IAB network is shown according to one embodiment.

[0009] Figure 4 An exemplary protocol architecture for IAB is shown according to one embodiment.

[0010] Figure 5 An exemplary IAB network is shown according to one embodiment.

[0011] Figure 6 An IAB architecture according to one embodiment is shown.

[0012] Figure 7 A system according to one embodiment is shown.

[0013] Figure 8 An NG-RAN architecture according to one embodiment is shown.

[0014] Fig. 9 An apparatus according to one embodiment is shown.

[0015] Fig.10 An exemplary interface according to one embodiment is shown.

[0016] Fig.11 Components according to one embodiment are shown. DETAILED DESCRIPTION

[0017] The present disclosure relates to Integrated Access and Backhaul (IAB), which is a feature designed in 3GPP to implement multi-hop routing. IAB nodes serve as both access nodes to UEs and provide backhaul links to other IAB nodes. Embodiments herein provide flow control mechanisms on the uplink in such networks.

[0018] The goal of flow control is to control the incoming data rate so that packets are not dropped due to buffer overflow. In other words, flow control attempts to ensure that the incoming data rate matches the capacity of the link through which the data is traveling. For example, in the downlink, when the route includes a sequence of links from donor to node 1 to node 2 to node 3 (see e.g. Figure 6 ), Node 1 does not know when the downlink buffer at Node 2 is close to overflowing. This will happen when the link from Node 2 to Node 3 is congested. This requires a "back pressure" mechanism that attempts to slow down the incoming data from the donor over the link from Node 2 to Node 3.

[0019] A similar congestion situation may occur on the uplink route (node ​​3 to node 2 to node 1 to donor). That is, congestion on the link from node 1 to the donor may cause an uplink buffer overflow at node 1. However, for uplink traffic, node 1 can mitigate the buffer overflow risk by allocating less uplink resources for node 2 to node 1 transmission (known as implicit backpressure). However, this may cause a buffer overflow risk at node 2. In response, node 2 allocates less uplink resources, and this causes congestion to creep along the route. If the data rate injected into node 3 is high, this slow backpressure mechanism may not be able to avoid buffer overflow.

[0020] Given that dropping packets is highly undesirable (e.g., will result in retransmissions, result in initiation of transmission control protocol (TCP) congestion avoidance, etc.), having robust flow control is useful. However, if the congestion on the link is long-term, flow control cannot solve the problem. In such cases, it may be necessary to identify alternative routes and map the bearers to routes that take into account the congested links. Certain embodiments herein mitigate the effects of the above-described implicit backpressure mechanisms and / or propose alternative methods.

[0021] Congestion occurrences on a link can be categorized into at least two types. In one type of congestion, the signal-to-noise ratio (SNR) on the link drops significantly, resulting in the link being unable to support the ongoing or promised data rate of the bearer. This drop in SNR can be short-term or long-term. In another type of congestion, when multiple variable data rate bearers are multiplexed onto the link, the amount of data generated for the multiple bearers can peak at the same time. The congestion caused by this event is usually short-lived.

[0022] Figure 1Schematically illustrates an exemplary IAB network 100 including an IAB donor 102 and five IAB nodes, the IAB nodes including a first node 104 (node ​​1), a second node 106 (node ​​2), a third node 108 (node ​​3), a fourth node 110 (node ​​4) and a fifth node 112 (node ​​5). As used herein, an IAB node may also be referred to as a relay node. A relay node may receive uplink traffic (represented by an arrow) from a downlink or child relay node (or from a UE), and provide the uplink traffic to a parent relay node. Uplink traffic from UEs associated with three users (user A 114, user B 116 and user C 118) is routed through the exemplary IAB network 100. User A and user B are attached to the fifth node 112, and user C is attached to the fourth node 110. The uplink traffic of user A is routed through the fourth node 110, the second node 106 and the first node 104. The uplink traffic of user B is routed through the fourth node 110, the third node 108, and the first node 104. The uplink traffic of user C is routed through the second node 106 and the first node 104. Figure 1 The arrows shown (and Figure 3 and Figure 5 Some of the arrows shown in the figure represent uplink traffic, but those skilled in the art will recognize from the disclosure herein that the IAB node can also be used for downlink traffic. See, e.g. Figure 6 Description of an exemplary IAB architecture 600 .

[0023] If the link from the second node 106 to the first node 104 experiences congestion, the second node 106 may apply back pressure, as discussed above. That is, the second node 106 limits uplink resource allocations to the fourth node 110. The second node 106 uses the buffer level to decide when to apply back pressure.

[0024] When the second node 106 starts to apply back pressure, the fourth node 110 is still unaware of any congestion problem. In addition, the UEs of user A, user B, and user C continue to push data into the network (i.e., they request uplink resources from their corresponding serving IAB nodes and are allocated resources because the IAB nodes are unaware of the congestion problem between the second node 106 and the first node 104). The buffers at the fourth node 110 and the fifth node 112 eventually reach a level at which their corresponding back pressure mechanisms are triggered and the resources allocated to the UEs are reduced. However, between the time when the back pressure mechanism is triggered at the second node 106 and the time when the fourth node 110 and the fifth node 112 trigger their corresponding back pressure mechanisms, a large amount of data has entered the network.

[0025] Figure 2Schematically illustrates an IAB node uplink buffer 200 according to one embodiment. The shaded portion of the IAB node uplink buffer 200 represents the instantaneous buffer occupancy percentage. When the instantaneous buffer occupancy percentage reaches a predetermined occupancy level 202, the backpressure mechanism is triggered. Figure 2 In the example shown, the predetermined occupancy level 202 corresponds to C% of the overall IAB node uplink buffer 200 capacity.

[0026] See also Figure 1 and Figure 2 , in order to reduce the number of dropped packets and / or ensure that no packets are dropped, for example, when the second node 106 activates a backpressure mechanism, the second node 106 may ensure that it can accommodate data that will continue to enter the network until the IAB node serving the UE activates its backpressure mechanism. This implies adjusting the level at which the backpressure mechanism is triggered based on the length of the route and the number of UEs ( Figure 2 As the length of the route increases and the number of UEs increases, this may result in a smaller value of the predetermined occupancy level 202 (C%), leading to a significant underutilization of the buffer.

[0027] The embodiments herein provide a mechanism for reacting to uplink congestion on a route faster than conventional mechanisms. Certain embodiments include delivering buffer occupancy information of an uplink buffer to a node as a downlink node at each IAB node. The embodiments enable the downlink node to consider buffer limitations along the route when performing uplink resource allocation. The faster reaction to congestion enables less data to be injected into the network after a congestion condition has been observed.

[0028] Buffer occupancy refers to the portion of the buffer that includes data awaiting transmission. According to various embodiments, buffer occupancy information is delivered to downstream nodes. Figure 3 FIG. 3 shows an exemplary IAB network 300 in which an explicit back pressure mechanism is used. Figure 1 As shown, Figure 3The exemplary IAB network 300 shown includes an IAB donor 102 and five IAB nodes, including a first node 104, a second node 106, a third node 108, a fourth node 110, and a fifth node 112. Uplink traffic from UEs associated with three users (user A 114, user B 116, and user C 118) is routed through the exemplary IAB network 300. User A and user B are attached to the fifth node 112, and user C is attached to the fourth node 110. User A's traffic is routed through the fourth node 110, the second node 106, and the first node 104. User B's traffic is routed through the fourth node 110, the third node 108, and the first node 104. User C's traffic is routed through the second node 106 and the first node 104.

[0029] exist Figure 3 In the example of Figure 3 304, the second node 106 transmits a buffer occupancy status 304 to its child nodes when the possibility of congestion on the link (indicated by arrow 302 in FIG. 1 ) reaches a critical level. That is, the second node 106 transmits a message (referred to as a “buffer occupancy status” (BOS) message, etc.) including its instantaneous buffer occupancy to the fourth node 110. The buffer occupancy status message may express or otherwise indicate the instantaneous buffer occupancy as a percentage (e.g., “X%”), an amount of occupied memory space, an amount of free space, and / or any other suitable indication, such as those discussed herein.

[0030] In certain embodiments, since the uplink buffer of the fourth node 110 is close to overflowing, the fourth node will allocate less resources for the fourth node 110 to the second node 106 transmission. When allocating resources for the fifth node 112 to 110 transmission, the fourth node 110 takes into account the buffer occupancy at the second node 106. Specifically, the fourth node 110 receives a buffer status report (BSR) from the fifth node 112 indicating the amount of buffered uplink data at the fifth node 112; and the fourth node 110 controls the data rate from the fifth node 112 to the fourth node 110 by controlling the uplink resources allocated to the fifth node 112, so that the risk of buffer overflow at the fourth node 110 is reduced or minimized. Without the indication of buffer occupancy of the exemplary embodiment, the buffer at the fourth node 110 would need to approach a critical level before the fourth node 110 begins to reduce the data rate from the fifth node 112 to the fourth node 110. According to certain embodiments herein, such delays in reducing the data rate are avoided.

[0031] The fourth node 110 also transmits a buffer occupancy status 306 to its child node, the fifth node 112. In some embodiments, the buffer occupancy status 306 may indicate a buffer occupancy that is the maximum of its own buffer occupancy (Y%) and the maximum of the buffer occupancy (X%) indicated by the node B. This approach enables a node to indicate in its buffer occupancy status message the highest buffer occupancy occurring along a given route.

[0032] In response to the buffer occupancy status 306 , the fifth node 112 controls the uplink resources allocated to transmissions from user A and user B such that the risk of buffer overflow at the fifth node 112 is minimized.

[0033] In some embodiments, the second node 106 may transmit the buffer occupancy status 304 to its child nodes, taking into account its own buffer occupancy and the buffer occupancy status received from its parent node. Since different bearers may be routed along different routes, the buffer occupancy is bearer specific and may be processed at the adaptation layer. This approach may enable faster awareness of congestion along the route. Each node may then take this information into account when allocating uplink resources.

[0034] Estimated buffer occupancy status

[0035] When a node receives data from a UE and its downlink nodes and transmits data to its parent node, the buffer occupancy may change rapidly. According to certain embodiments, in order to make the buffer occupancy metric more reflective of the situation when it is used, an estimated buffer occupancy may be defined. The estimated buffer occupancy is obtained by adding to and / or subtracting from the buffer.

[0036] Adding to the buffer includes adding a value corresponding to the size of the buffer status report received at the node, and recalculating the buffer occupancy. That is, buffered data awaiting transmission to the node for which a buffer status report has been received is counted as having been received (the expected buffer occupancy attempts to show the buffer occupancy after receiving the data for which a BSR has been received).

[0037] Subtracting from the buffer includes subtracting a value corresponding to the size of the uplink grant received at the node and recalculating the buffer occupancy. That is, buffered data at the node that has been provided with uplink resources is not counted (the expected buffer occupancy attempts to show the buffer occupancy after transmitting and removing from the buffer the data for which an uplink grant has been received).

[0038] Buffer busy state trigger

[0039] As previously mentioned, the buffer occupancy status may be transmitted when the buffer occupancy reaches a predefined critical level. Alternatively (or additionally), the buffer occupancy status may be transmitted when the node receives a BSR from a child IAB node. That is, the buffer occupancy status may be transmitted in response to a BSR.

[0040] Buffer busy state timeout

[0041] Given that buffer occupancy can be quite dynamic, its validity may not exceed a few hundred milliseconds. A timer may be used to control how long the buffer occupancy is considered valid by an IAB node that receives the buffer occupancy status (BOS). When the timer expires, the BOS is discarded. In addition, a new BOS received from a node overwrites a previously stored BOS.

[0042] One embodiment uses a preconfigured value for the validity timer duration. In another embodiment, an expiration time (based on a common network-wide time reference) may be included in the BOS. In this approach, each child node uses the expiration time provided by the parent node when generating its BOS.

[0043] In the above method, the IAB node receiving the BOS generates its own BOS based on the received BOS for transmission to other nodes. As an alternative, the IAB node may simply relay (retransmit) the received BOS and also transmit its own BOS independently (in this case, its own BOS will not be involved in the comparison of the two buffer occupancies).

[0044] Example Protocol Architecture for Buffer Occupancy Status (BOS)

[0045] Figure 4An exemplary protocol architecture for an IAB 400 according to one embodiment is shown. The exemplary protocol architecture of the IAB 400 shows various protocol layers of a UE 402, a first IAB node 404 (IAB node 1), a second IAB node 406 (IAB node 2), and an IAB donor 408. Each layer may correspond to a mobile station called (MT), a distributed unit (DU), or a centralized unit (CU)-user plane (UP) entity. The DU and CU-UP of the IAB donor 408 may communicate via an intra-donor F1-U interface. In this example, the UE 402 wirelessly communicates with the second IAB node 406 via a dedicated radio bearer (DRB) of the UE, and the second IAB node 406 wirelessly relays uplink traffic to the first IAB node 404 via a backhaul (BH) radio link control (RLC) channel. The protocol layers include, for example, Medium Access Control (MAC), RLC, Packet Data Convergence Protocol (PDCP), Service Data Adaptation Protocol (SDAP), Internet Protocol (IP), User Datagram Protocol (UDP), and General Packet Radio Service (GPRS) Tunneling Protocol-User Plane (GTP-U).

[0046] The exemplary protocol architecture of IAB 400 also includes a backhaul adaptation protocol (BAP) layer, which may also be referred to as an "adaptation" layer (or simply adaptation layer), which provides functionality for routing data for different UE bearers over different routes through the network. This can be accomplished by having an adaptation layer header that includes some information for identifying the bearer. Routing includes mapping incoming data to outgoing links based on the bearer identifier.

[0047] Given that different UE bearers may be carried on different routes through the network, in certain embodiments the buffer occupancy status generated by a node is only relevant to the bearers routed through that node and the IAB nodes on those routes.

[0048] refer to Figure 5 , for example, the link from the second node 106 to the first node 104 carries traffic for user A and user C, but does not carry traffic for user B and user D. Therefore, the buffer occupancy status generated by the IAB second node 106 is only relevant to the bearer carrying traffic for user A and user C (and therefore to the IAB fourth node 110 and fifth node 112). Therefore, the BOS message should follow the same route as the bearer. For example, the BOS message generated by the second node 106 is sent to the fourth node 110; the fourth node 110 generates its BOS message based on the received BOS message and transmits the BOS message to the fifth node 112. It should be noted that although the BOS message generated by the fourth node 110 is not sent to the sixth node 502, the data of user D is received at the fourth node 110 via the sixth node 502.

[0049] refer to Figure 4 and Figure 5 To facilitate proper routing, the BOS functionality may be placed in the BAP layer or the adaptation layer. That is, the BOS message may be defined as a BAP layer control protocol data unit (PDU). Information about buffer occupancy may be received from the RLC layer or the MAC layer, which specifically maintains a buffer for untransmitted data.

[0050] Please note that Figure 4 The BAP layer placement in is only an example. If the BAP layer is placed, for example, between the RLC layer and the MAC layer, the same principle holds.

[0051] In certain embodiments, if congestion occurs at the first node 104 to IAB donor link, a BOS is generated and transmitted in the following order: first node 104 to second node 106 to fourth node 110 to fifth node 112; and / or first node 104 to third node 108 to fourth node 110 to sixth node 502.

[0052] Alternative metrics for congestion indication

[0053] The above description defines buffer occupancy as the portion of the buffer used for data awaiting transmission.Alternative metrics that may be considered include: buffer availability (unused portion of the buffer); and / or available remaining buffer capacity (in bytes).

[0054] Additionally, or in other embodiments, rather than using a metric as defined above, the BOS may simply indicate whether the link is approaching congestion (eg, a 1-bit yes / no indication to cause the receiving node to reduce the uplink data rate).

[0055] Note also that when the buffer occupancy status is constructed by an IAB node when receiving a BOS from a parent node, it may use another function (such as an average) rather than a maximum value to calculate the buffer occupancy value to include in its BOS.

[0056] In an exemplary embodiment, a method in a first relay node includes: determining that an uplink buffer at the relay node has reached an occupancy level above a predetermined level; transmitting a message indicating the buffer occupancy status of the uplink buffer of the first relay node to a second relay node associated with the first relay node.

[0057] In another exemplary embodiment, a method in a first relay node includes: receiving a message indicating a buffer occupancy status of an uplink buffer of the second relay node from a second relay node; determining the buffer occupancy status based on the buffer occupancy status of the uplink buffer of the second relay node and the buffer occupancy status of the uplink buffer of the first relay node; and transmitting the buffer occupancy status to a third relay node, wherein the third relay node is associated with the first relay node.

[0058] Figure 6 An exemplary IAB architecture 600 according to one embodiment is shown. The exemplary IAB architecture 600 includes a 5GC 602, a donor node 604, a plurality of IAB nodes (six IAB nodes, shown as IAB relay nodes 606) and a plurality of UEs (six UEs, shown as UE 608). The donor node 604 may include a centralized unit (CU, shown as CU 610) and a distributed unit (DU, shown as DU 612). The CU 610 may be divided into, for example, a control plane CU and a user plane CU. In addition, although only one DU 612 is shown, the DU 612 may include a plurality of distributed units. As shown, the solid line between the CU 610 and the 5GC 602 and the DU 612 may represent a wired link, while the dotted line may represent a wireless link.

[0059] Each IAB relay node 606 (also referred to herein as an IAB RN or "relay transmission / reception point" or "rTRP") is a network node in an IAB deployment that has the functionality of a UE and the functionality of a gNB (at least a portion of it). As shown, some IAB RNs access other IAB RNs, and some IAB RNs access donor nodes 604. An IAB DN (or IAB donor, also referred to as an "anchor node", etc.) is a network node in an IAB deployment that terminates the NG interface via a wired connection. An IAB DN is a RAN node that provides an interface to the UE to the core network (shown as 5GC 102) and provides wireless backhaul functionality to the IAB node. An IAB node is a relay node and / or RAN node that supports wireless access to the UE and wireless backhaul access traffic.

[0060] In an embodiment, the IAB system architecture supports multi-hop backhaul. The IAB multi-hop backhaul provides greater range extension than a single-hop system. The multi-hop backhaul also enables backhaul around obstacles (e.g., for buildings in a cluttered urban environment). The maximum number of hops in an expected deployment depends on many factors, such as frequency, cell density, propagation environment, traffic load, various key performance indicators (KPIs), and / or other similar factors. From an architectural perspective, flexibility in the number of hops is desirable, and therefore the IAB system may not impose restrictions on the number of backhaul hops.

[0061] The IAB system architecture also supports topology adaptation. Topology adaptation refers to the process of autonomously reconfiguring the backhaul network without interrupting service to the UE and / or alleviating service disruption to the UE in situations such as blocking or local congestion. For example, wireless backhaul links may be easily blocked due to moving objects such as vehicles, weather-related events (e.g., seasonal changes (leaves), infrastructure changes (e.g., new buildings), etc. These vulnerabilities may apply to physically stationary IAB nodes and / or mobile IAB nodes. In addition, traffic changes may produce uneven load distribution on the wireless backhaul links, resulting in local link or node congestion.

[0062] In an implementation scheme that supports multi-hop and topology adaptation, the IAB node includes a topology management mechanism and a route selection and optimization (RSO) mechanism. The topology management mechanism includes a protocol stack, an interface between rTRPs or IAB nodes, control and user plane procedures for identifying one or more hops in the IAB network, forwarding traffic via one or more wireless backhaul links in the IAB network, QoS processing, etc. The RSO mechanism includes a mechanism for discovering and managing the backhaul link of a TRP with integrated backhaul and access functions; a RAN-based mechanism for supporting dynamic route selection (possibly without core network involvement) to adapt to short-term blocking and transmission of delay-sensitive traffic on the entire backhaul link; and a mechanism for evaluating different resource allocation / routing across multiple nodes for end-to-end RSO.

[0063] The operation of different links may be performed on the same frequency ("in-band") or on different frequencies ("out-of-band"). In-band backhaul includes scenarios where the access link and the backhaul link at least partially overlap in frequency, resulting in half-duplex or interference constraints, which may imply that the IAB node may not transmit and receive simultaneously on both links. In contrast, out-of-band scenarios may not have such constraints. In an embodiment, one or more of the IAB nodes include a mechanism for dynamically allocating resources between the backhaul link and the access link, including a mechanism for efficiently multiplexing the access link and the backhaul link (for both the DL direction and the UL direction) in time, frequency, or space under a per-link half-duplex constraint on one or more backhaul link hops for both TDD and FDD operations; and cross-link interference (CLI) measurement, coordination, and mitigation between rTRPs and UEs.

[0064] Figure 7 The architecture of a system 700 of a network according to some embodiments is shown. The system 700 is shown to include a UE 702; a 5G access node or RAN node (shown as (R) AN node 708); a user plane function (shown as UPF 704); a data network (DN 706), which may be, for example, an operator service, Internet access, or a 3rd party service; and a 5G core network (5GC) (shown as CN 710).

[0065] CN 710 may include an authentication server function (AUSF 714); a core access and mobility management function (AMF 712); a session management function (SMF 718); a network exposure function (NEF 716); a policy control function (PCF 722); a network function (NF) repository function (NRF 720); a unified data management (UDM 724); and an application function (AF 726). CN 710 may also include other elements not shown, such as a structured data storage network function (SDSF), an unstructured data storage network function (UDSF), etc.

[0066] UPF 704 may act as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point interconnected with DN 706, and a branch point to support multi-homed PDU sessions. UPF 704 may also perform packet routing and forwarding, perform packet inspection, enforce the user plane portion of policy rules, lawfully intercept packets (UP collection); traffic usage reporting, perform QoS processing on the user plane (e.g., packet filtering, gating, UL / DL rate enforcement), perform uplink traffic verification (e.g., SDF to QoS flow mapping), transport level packet marking in uplink and downlink, and downlink packet buffering and downlink data notification triggering. UPF 704 may include an uplink classifier to support routing of traffic to a data network. DN 706 may represent various network operator services, Internet access, or third-party services.

[0067] AUSF 714 may store data and handle authentication-related functions for authenticating UE 702. AUSF 714 may facilitate a common authentication framework for various access types.

[0068] AMF 712 may be responsible for registration management (e.g., responsible for registering UE 702, etc.), connection management, reachability management, mobility management, and lawful interception of AMF-related events, and access authentication and authorization. AMF 712 may provide transport for SM messages of SMF 718 and act as a transparent proxy for routing SM messages. AMF 712 may also provide services for UE 702 and SMS function (SMSF) ( Figure 7The AMF 712 may provide for the transmission of short message service (SMS) messages between the AUSF 714 and the UE 702 (not shown). The AMF 712 may act as a security anchor function (SEA), which may include interaction with the AUSF 714 and the UE 702, receiving intermediate keys established as a result of the UE 702 authentication process. In the case of using USIM-based authentication, the AMF 712 may retrieve security information from the AUSF 714. The AMF 712 may also include a secure content management (SCM) function that receives keys from the SEA for deriving access network specific keys. In addition, the AMF 712 may be the termination point for the RAN CP interface (N2 reference point), the termination point for NAS (NI) signaling, and perform NAS encryption and integrity protection.

[0069] AMF 712 may also support NAS signaling with UE 702 via the N3 interworking function (IWF) interface. N3IWF may be used to provide access to untrusted entities. N3IWF may be an endpoint of the N2 and N3 interfaces for the control plane and user plane, respectively, and may therefore handle N2 signaling for PDU sessions and QoS from SMF and AMF, encapsulate / decapsulate packets for IPSec and N3 tunnels, mark N3 user plane packets in the uplink, and enforce QoS corresponding to the N3 packet marking taking into account the QoS requirements associated with such markings received via N2. N3IWF may also relay uplink and downlink control plane NAS (NI) signaling between UE 702 and AMF 712, and relay uplink and downlink user plane packets between UE 702 and UPF 704. N3IWF also provides a mechanism for establishing an IPsec tunnel with UE 702.

[0070] SMF 718 may be responsible for session management (e.g., session establishment, modification, and release, including tunnel maintenance between UPF and AN nodes); UE IP address allocation & management (including optional authorization); selection and control of UP functions; configuring traffic steering at UPF to route traffic to the correct destination; terminating the interface towards the policy control function; control part of policy enforcement and QoS; lawful interception (for SM events and interface with LI system); terminating the SM part of NAS messages; downlink data notification; initiator of AN-specific SM information sent to AN via AMF over N2; determining the SSC mode of the session. SMF 718 may include the following roaming functions: handling local execution to apply QoS SLA (VPLMN); charging data collection and charging interface (VPLMN); lawful interception (for SM events and interface with LI system, in VPLMN); supporting interaction with external DNs to transmit signaling for PDU session authorization / authentication over external DNs.

[0071] NEF 716 may provide a means for securely exposing services and capabilities provided by 3GPP network functions for third parties, internal exposure / re-exposure, application functions (e.g., AF 726), edge computing or fog computing systems, etc. In such embodiments, NEF 716 may authenticate, authorize and / or restrict AF. NEF 716 may also convert information exchanged with AF 726 and information exchanged with internal network functions. For example, NEF 716 may convert between AF service identifiers and internal 5GC information. NEF 716 may also receive information from other network functions (NFs) based on the exposure capabilities of other network functions. The information may be stored at NEF 716 as structured data, or at a data storage NF using a standardized interface. The stored information may then be re-exposed to other NFs and AFs by NEF 716, and / or used for other purposes such as analysis.

[0072] NRF 720 may support service discovery functionality, receive NF discovery requests from NF instances, and provide information of discovered NF instances to NF instances. NRF 720 also maintains information of available NF instances and the services they support.

[0073] PCF 722 may provide for control plane functions to enforce their policy rules and may also support a unified policy framework for managing network behavior. PCF 722 may also implement a front end (FE) to access subscription information related to policy decisions in the UDR of UDM 724.

[0074] UDM 724 may process subscription-related information to support the handling of communication sessions by network entities, and may store subscription data for UE 702. UDM 724 may include two parts: an application FE and a user data repository (UDR). UDM may include a UDM FE that is responsible for handling credentials, location management, subscription management, and the like. In different transactions, several different front ends may serve the same user. UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing; user identity processing; access authorization; registration / mobility management; and subscription management. The UDR may interact with PCF 722. UDM 724 may also support SMS management, where the SMS-FE implements similar application logic as previously discussed.

[0075] AF 726 can provide application influence on traffic routing, access to network capability exposure (NCE), and interact with the policy framework for policy control. NCE can be a mechanism that allows 5GC and AF 726 to provide information to each other via NEF 716, which can be used for edge computing implementation. In such implementations, network operators and third-party services can be hosted near the UE 702 access point of the attachment to achieve effective service delivery through reduced end-to-end delay and load on the transmission network. For edge computing implementation, 5GC can select UPF 704 near UE 702 and perform traffic steering from UPF 704 to DN 706 via N6 interface. This can be based on UE subscription data, UE location and information provided by AF 726. In this way, AF 726 can affect UPF (re) selection and traffic routing. Based on operator deployment, when AF 726 is considered a trusted entity, the network operator can allow AF 726 to interact directly with the relevant NF.

[0076] As previously discussed, CN 710 may include SMSF, which may be responsible for SMS subscription checking and verification, and relaying SM messages from / to other entities such as SMS-GMSC / IWMSC / SMS routers to / from UE 702. SMS may also interact with AMF 712 and UDM 724 for notification procedures so that UE 702 is available for SMS delivery (e.g., setting a UE unreachable flag and notifying UDM 724 when UE 702 is available for SMS).

[0077] System 700 may include the following service-based interfaces: Namf: a service-based interface presented by AMF; Nsmf: a service-based interface presented by SMF; Nnef: a service-based interface presented by NEF; Npcf: a service-based interface presented by PCF; Nudm: a service-based interface presented by UDM; Naf: a service-based interface presented by AF; Nnrf: a service-based interface presented by NRF; and Nausf: a service-based interface presented by AUSF.

[0078] System 700 may include the following reference points: N1: a reference point between UE and AMF; N2: a reference point between (R)AN and AMF; N3: a reference point between (R)AN and UPF; N4: a reference point between SMF and UPF; and N6: a reference point between UPF and data network. There may be more reference points and / or service-based interfaces between NF services in these NFs, however, these interfaces and reference points are omitted for clarity. For example, the NS reference point may be between PCF and AF; the N7 reference point may be between PCF and SMF; the N11 reference point may be between AMF and SMF, etc.; etc. In some embodiments, CN 710 may include an Nx interface, which is an inter-CN interface between MME and AMF 712 to enable intercommunication between CN 710 and the LTE core network.

[0079] although Figure 7 Not shown, but the system 700 may include multiple RAN nodes (such as (R)AN node 708), where the Xn interface is defined as between two or more (R)AN nodes 708 (e.g., gNBs, etc.) connected to the 5GC 410, between an (R)AN node 708 (e.g., gNB) connected to the CN710 and an eNB, and / or between two eNBs connected to the CN 710.

[0080] In some specific implementations, the Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U may provide non-guaranteed delivery of user plane PDUs and support / provide data forwarding and flow control functions. The Xn-C may provide management and error handling functions for managing the functions of the Xn-C interface; mobility support for UE 702 in connected mode (e.g., CM connection) includes functions for managing UE mobility in connected mode between one or more (R)AN nodes 708. Mobility support may include context transfer from an old (source) serving (R)AN node 708 to a new (target) serving (R)AN node 708; and control of a user plane tunnel between the old (source) serving (R)AN node 708 and the new (target) serving (R)AN node 708.

[0081] The protocol stack of Xn-U may include a transport network layer built on an Internet Protocol (IP) transport layer, and a GTP-U layer for carrying user plane PDUs on top of a UDP and / or IP layer. The Xn-C protocol stack may include an application layer signaling protocol (referred to as the Xn Application Protocol (Xn-AP)) and a transport network layer built on an SCTP layer. The SCTP layer may be located on top of the IP layer. The SCTP layer provides guaranteed delivery of application layer messages. In the transport IP layer, point-to-point transmission is used to deliver signaling PDUs. In other specific implementations, the Xn-U protocol stack and / or the Xn-C protocol stack may be the same or similar to the user plane and / or control plane protocol stacks shown and described herein.

[0082] Figure 8 An NG-RAN architecture 800 is shown according to one embodiment, which includes a 5GC 802 and a NG-RAN 804. The NG-RAN 804 includes multiple gNBs (two gNBs shown as gNB 806 and gNB 808) connected to the 5GC 802 via an NG interface. The gNB 806 and gNB 808 may support FDD mode, TDD mode, or dual mode operation and are connected to each other via an Xn-C interface. As shown, the gNB 808 includes a gNB-CU 810 connected to a gNB-DU 812 and a gNB-DU 814 via an F1 interface. The gNB 808 may include only a single gNB-DU or more than the two gNB-DUs shown. The NG interface, the Xn-C interface, and the F1 interface are logical interfaces.

[0083] Fig. 9 Exemplary components of a device 900 according to some embodiments are shown. In some embodiments, the device 900 may include an application circuit 902, a baseband circuit 904, a radio frequency (RF) circuit (shown as an RF circuit 920), a front-end module (FEM) circuit (shown as an FEM circuit 930), one or more antennas 932, and a power management circuit (PMC) (shown as a PMC 934) coupled together at least as shown. The components of the illustrated device 900 may be included in a UE or a RAN node. In some embodiments, the device 900 may include fewer elements (e.g., a RAN node may not utilize an application circuit 902, but include a processor / controller to process IP data received from an EPC). In some embodiments, the device 900 may include additional elements, such as a memory / storage device, a display, a camera, a sensor, or an input / output (I / O) interface. In other embodiments, the following components may be included in more than one device (e.g., the circuit may be separately included in more than one device for a specific implementation of a cloud-RAN (C-RAN)).

[0084] The application circuit 902 may include one or more application processors. For example, the application circuit 902 may include circuits such as, but not limited to, one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). These processors may be coupled to or may include memory / storage devices, and may be configured to execute instructions stored in the memory / storage devices to enable various applications or operating systems to run on the device 900. In some embodiments, the processor of the application circuit 902 may process IP data packets received from the EPC.

[0085] The baseband circuit 904 may include circuits such as, but not limited to, one or more single-core or multi-core processors. The baseband circuit 904 may include one or more baseband processors or control logic components to process baseband signals received from the receive signal path of the RF circuit 920 and generate baseband signals for the transmit signal path of the RF circuit 920. The baseband circuit 904 may interact with the application circuit 902 to generate and process baseband signals and control the operation of the RF circuit 920. For example, in some embodiments, the baseband circuit 904 may include a third generation (3G) baseband processor (3G baseband processor 906), a fourth generation (4G) baseband processor (4G baseband processor 908), a fifth generation (5G) baseband processor (5G baseband processor 910), or other baseband processors 912 of other existing generations, generations under development, or generations to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuit 904 (e.g., one or more of the baseband processors) may handle various radio control functions that implement communication with one or more radio networks via the RF circuit 920. In other embodiments, some or all of the functions of the illustrated baseband processor may be included in a module stored in the memory 918 and executed via the central processing unit (CPU 914). The radio control functions may include, but are not limited to, signal modulation / demodulation, encoding / decoding, radio frequency shifting, etc. In some embodiments, the modulation / demodulation circuit of the baseband circuit 904 may include a fast Fourier transform (FFT), precoding, or constellation mapping / demapping function. In some embodiments, the encoding / decoding circuit of the baseband circuit 904 may include convolution, tail-biting convolution, turbo, Viterbi, or low-density parity check (LDPC) encoder / decoder functions. The implementation of the modulation / demodulation and encoder / decoder functions is not limited to these examples, and may include other suitable functions in other embodiments.

[0086] In some embodiments, the baseband circuit 904 may include a digital signal processor (DSP), such as one or more audio DSPs 916. The one or more audio DSPs 916 may include elements for compression / decompression and echo cancellation, and may include other suitable processing elements in other embodiments. In some embodiments, the components of the baseband circuit may be appropriately combined in a single chip, a single chipset, or disposed on the same circuit board. In some embodiments, some or all of the components of the baseband circuit 904 and the application circuit 902 may be implemented together, such as on a system on a chip (SOC).

[0087] In some embodiments, the baseband circuit 904 may provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuit 904 may support communications with an Evolved Universal Terrestrial Radio Access Network (EUTRAN) or other wireless metropolitan area network (WMAN), wireless local area network (WLAN), wireless personal area network (WPAN). Embodiments in which the baseband circuit 904 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuits.

[0088] The RF circuit 920 may communicate with a wireless network through a non-solid medium using modulated electromagnetic radiation. In various embodiments, the RF circuit 920 may include switches, filters, amplifiers, etc. to facilitate communication with the wireless network. The RF circuit 920 may include a receive signal path, which may include circuits for down-converting RF signals received from the FEM circuit 930 and providing baseband signals to the baseband circuit 904. The RF circuit 920 may also include a transmit signal path, which may include circuits for up-converting baseband signals provided by the baseband circuit 904 and providing an RF output signal for transmission to the FEM circuit 930.

[0089] In some embodiments, the receive signal path of the RF circuit 920 may include a mixer circuit 922, an amplifier circuit 924, and a filter circuit 926. In some embodiments, the transmit signal path of the RF circuit 920 may include a filter circuit 926 and a mixer circuit 922. The RF circuit 920 may also include a synthesizer circuit 928 for synthesizing the frequency used by the mixer circuit 922 of the receive signal path and / or the transmit signal path. In some embodiments, the mixer circuit 922 of the receive signal path may be configured to down-convert the RF signal received from the FEM circuit 930 based on the synthesized frequency provided by the synthesizer circuit 928. The amplifier circuit 924 may be configured to amplify the down-converted signal, and the filter circuit 926 may be a low pass filter (LPF) or a band pass filter (BPF) configured to remove unwanted signals from the down-converted signal to generate an output baseband signal. The output baseband signal may be provided to the baseband circuit 904 for further processing. In some embodiments, although this is not required, the output baseband signal may be a zero frequency baseband signal. In some embodiments, mixer circuit 922 of the receive signal path may include a passive mixer, although the scope of the embodiments is not limited in this respect.

[0090] In some embodiments, mixer circuit 922 of the transmit signal path may be configured to up-convert an input baseband signal based on a synthesized frequency provided by synthesizer circuit 928 to generate an RF output signal for FEM circuit 930. The baseband signal may be provided by baseband circuit 904 and may be filtered by filter circuit 926.

[0091] In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may include two or more mixers and may be arranged for quadrature down-conversion and up-conversion, respectively. In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may be arranged for direct down-conversion and direct up-conversion, respectively. In some embodiments, the mixer circuit 922 of the receive signal path and the mixer circuit 922 of the transmit signal path may be configured for superheterodyne operation.

[0092] In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, the RF circuit 920 may include an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC) circuit, and the baseband circuit 904 may include a digital baseband interface to communicate with the RF circuit 920.

[0093] In some dual-mode embodiments, separate radio IC circuits may be provided to process signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[0094] In some embodiments, synthesizer circuit 928 may be a fractional-N synthesizer or a fractional N / N+1 synthesizer, but the scope of the embodiments is not limited in this regard, as other types of frequency synthesizers may also be suitable. For example, synthesizer circuit 928 may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase-locked loop with a frequency divider.

[0095] The synthesizer circuit 928 may be configured to synthesize an output frequency based on the frequency input and the divider control input for use by the mixer circuit 922 of the RF circuit 920. In some embodiments, the synthesizer circuit 928 may be a fractional-N / N+1 synthesizer.

[0096] In some embodiments, the frequency input may be provided by a voltage controlled oscillator (VCO), although this is not required. The divider control input may be provided by baseband circuitry 904 or application circuitry 902 (such as an application processor) according to the desired output frequency. In some embodiments, the divider control input (e.g., N) may be determined from a lookup table based on the channel indicated by application circuitry 902.

[0097] The synthesizer circuit 928 of the RF circuit 920 may include a frequency divider, a delay locked loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the frequency divider may be a dual-mode frequency divider (DMD), and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by N or N+1 (e.g., based on carry) to provide a fractional division ratio. In some example embodiments, the DLL may include a cascaded, tunable, delay element, a phase detector, a charge pump, and a D-type flip-flop set. In these embodiments, the delay element may be configured to divide the VCO cycle into Nd equal phase groups, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0098] In some embodiments, the synthesizer circuit 928 can be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and can be used with a quadrature generator and divider circuit to generate multiple signals with multiple different phases relative to each other at the carrier frequency. In some embodiments, the output frequency can be the LO frequency (fLO). In some embodiments, the RF circuit 920 can include an IQ / polarity converter.

[0099] The FEM circuitry 930 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 932, amplify the receive signals, and provide an amplified version of the receive signals to the RF circuitry 920 for further processing. The FEM circuitry 930 may also include a transmit signal path that may include circuitry configured to amplify transmit signals provided by the RF circuitry 920 for transmission by one or more of the one or more antennas 932. In various embodiments, amplification by the transmit or receive signal path may be accomplished only in the RF circuitry 920, only in the FEM circuitry 930, or in both the RF circuitry 920 and the FEM circuitry 930.

[0100] In some embodiments, the FEM circuit 930 may include a TX / RX switch to switch between transmission mode and reception mode operation. The FEM circuit 930 may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuit 930 may include an LNA to amplify the received RF signal and provide the amplified received RF signal as an output (e.g., to the RF circuit 920). The transmit signal path of the FEM circuit 930 may include a power amplifier (PA) for amplifying an input RF signal (e.g., provided by the RF circuit 920); and one or more filters for generating an RF signal for subsequent transmission (e.g., through one or more of the one or more antennas 932).

[0101] In some embodiments, the PMC 934 can manage the power provided to the baseband circuit 904. Specifically, the PMC 934 can control power selection, voltage scaling, battery charging, or DC-DC conversion. When the device 900 is capable of being powered by a battery, for example, when the device 900 is included in a UE, the PMC 934 can generally be included. The PMC 934 can improve power conversion efficiency while providing the desired specific implementation size and heat dissipation characteristics.

[0102] Fig. 9PMC 934 is shown coupled only to baseband circuitry 904. However, in other embodiments, PMC 934 may additionally or alternatively be coupled to other components (such as, but not limited to, application circuitry 902, RF circuitry 920, or FEM circuitry 930) and perform similar power management operations for these components.

[0103] In some embodiments, the PMC 934 may control or otherwise be part of various power saving mechanisms of the device 900. For example, if the device 900 is in the RRC_Connected state, where the device is still connected to the RAN node because it expects to receive traffic immediately, then after a period of inactivity, the device may enter a state known as discontinuous reception mode (DRX). During this state, the device 900 may be powered off for short intervals, thereby saving power.

[0104] If there is no data traffic activity for an extended period of time, the device 900 may transition to the RRC_Idle state, in which the device is disconnected from the network and does not perform operations such as channel quality feedback, handover, etc. The device 900 enters a very low power state and performs paging, in which the device periodically wakes up again to listen to the network and then powers down again. The device 900 cannot receive data in this state, and in order to receive data, the device must transition back to the RRC_Connected state.

[0105] An additional power saving mode can keep a device from using the network for longer than the paging interval (which can range from a few seconds to several hours). During this time, the device is completely unable to connect to the network and can be completely powered down. Any data sent during this time will be significantly delayed, and it is assumed that the delay is acceptable.

[0106] The processor of the application circuit 902 and the processor of the baseband circuit 904 can be used to execute elements of one or more instances of the protocol stack. For example, the processor of the baseband circuit 904 can be used alone or in combination to perform layer 3, layer 2, or layer 1 functions, while the processor of the application circuit 902 can utilize data received from these layers (e.g., packet data) and further perform layer 4 functions (e.g., transport communication protocol (TCP) and user datagram protocol (UDP) layers). As mentioned herein, layer 3 may include a radio resource control (RRC) layer, which will be described in further detail below. As mentioned herein, layer 2 may include a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, which will be described in further detail below. As mentioned herein, layer 1 may include a physical (PHY) layer of a UE / RAN node, which will be described in further detail below.

[0107] Fig.10An exemplary interface 1000 of a baseband circuit according to some embodiments is shown. As discussed above, Fig. 9 The baseband circuit 904 may include a 3G baseband processor 906, a 4G baseband processor 908, a 5G baseband processor 910, other baseband processors 912, a CPU 914, and a memory 918 used by the processors. As shown, each of the processors may include a corresponding memory interface 1002 to send / receive data to / from the memory 918.

[0108] The baseband circuit 904 may also include one or more interfaces to communicatively couple to other circuits / devices, such as a memory interface 1004 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904), an application circuit interface 1006 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904), and an application circuit interface 1007 (e.g., an interface for sending / receiving data to / from a memory external to the baseband circuit 904). Fig. 9 1008 (for example, an interface for sending / receiving data to / from the application circuit 902) and an RF circuit interface 1008 (for example, an interface for sending / receiving data to / from the application circuit 902). Fig. 9 an interface for sending / receiving data to / from a RF circuit 920), a wireless hardware connection interface 1010 (e.g., for sending / receiving data to / from a near field communication (NFC) component, Parts (e.g. Low power consumption), components and other communication components to send / receive data) and a power management interface 1012 (for example, an interface for sending / receiving power or control signals to / from the PMC 934).

[0109] Fig.11 1 is a block diagram illustrating a component 1100 capable of reading instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and capable of performing any one or more of the methods discussed herein, according to some exemplary embodiments. Specifically, Fig.11 A diagrammatic representation of hardware resources 1102 is shown including one or more processors 1112 (or processor cores), one or more memory / storage devices 1118, and one or more communication resources 1120, each of which may be communicatively coupled via a bus 1122. For embodiments in which node virtualization (e.g., NFV) is utilized, a hypervisor 1104 may be executed to provide an execution environment for one or more network slices / sub-slices to utilize the hardware resources 1102.

[0110] Processor 1112 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) (such as a baseband processor), an application specific integrated circuit (ASIC), a radio frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, processor 1114 and processor 1116.

[0111] The memory / storage device 1118 may include main memory, disk storage, or any suitable combination thereof. The memory / storage device 1118 may include, but is not limited to, any type of volatile or non-volatile memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state storage, etc.

[0112] The communication resources 1120 may include interconnect or network interface components or other suitable devices to communicate with one or more peripheral devices 1106 or one or more databases 1108 via the network 1110. For example, the communication resources 1120 may include wired communication components (e.g., for coupling via a universal serial bus (USB)), cellular communication components, NFC components, Parts (e.g. Low power consumption), components and other communication components.

[0113] The instructions 1124 may include software, programs, applications, applet, applications, or other executable code for causing at least any one of the processors 1112 to perform any one or more of the methodologies discussed herein. The instructions 1124 may reside in whole or in part within at least one of the processor 1112 (e.g., within a cache memory of the processor), the memory / storage device 1118, or any suitable combination thereof. In addition, any portion of the instructions 1124 may be transmitted to the hardware resources 1102 from any combination of the peripheral device 1106 or the database 1108. Thus, the memory of the processor 1112, the memory / storage device 1118, the peripheral device 1106, and the database 1108 are examples of computer-readable and machine-readable media.

[0114] For one or more embodiments, at least one of the components shown in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes and / or methods described in the following example section. For example, the baseband circuit described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the following embodiments. For another example, the circuits associated with the UE, base station, network element, etc. described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the embodiments shown in the example section below.

[0115] Examples

[0116] The following examples relate to additional embodiments.

[0117] Embodiment 1 is an apparatus for flow control in a first relay node of a wireless communication network, the apparatus comprising an uplink buffer and a processor. The processor is used to: determine that the first relay node is experiencing congestion of uplink transmission; and in response to determining that the first relay node is experiencing congestion of uplink transmission, generate a message to a second relay node associated with the first relay node, the message indicating a buffer occupancy status of the uplink buffer of the first relay node.

[0118] Embodiment 2 is an apparatus according to embodiment 1, wherein the processor is further configured to: process one or more buffer status reports received at a first relay node; determine a buffer occupancy value of an uplink buffer of the first relay node, the buffer occupancy value corresponding to uplink traffic waiting to be transmitted in the uplink buffer; adjust the buffer occupancy value to calculate an expected buffer occupancy state of the uplink buffer of the first relay node by at least one of the following: increasing the buffer occupancy value based on the amount of buffered uplink data waiting to be transmitted to the first relay node indicated in one or more buffer status reports; and decreasing the buffer occupancy value based on an uplink grant received at the first relay node; and using the expected buffer occupancy state as the buffer occupancy state in a message to a second relay node.

[0119] Embodiment 3 is a device according to embodiment 1, wherein at least one buffer status report among the one or more buffer status reports comes from a second relay node, and wherein the second relay node is a downlink node of the first relay node, so that uplink traffic flows from the second relay node to the first relay node.

[0120] Embodiment 4 is the apparatus according to embodiment 1, wherein the message indicating the buffer occupancy status comprises an instantaneous buffer occupancy percentage of the uplink buffer of the first relay node.

[0121] Embodiment 5 is a device according to embodiment 1, wherein the processor is further configured to: process a buffer status report from a second relay node indicating the amount of uplink data buffered at the second relay node; process a buffer occupancy percentage value from a parent node; and based on the buffer status report and the buffer occupancy percentage value from the parent node, allocate uplink resources to the second relay node to control the uplink data rate of the second relay node.

[0122] Embodiment 6 is an apparatus according to embodiment 5, wherein the processor is further configured to determine a buffer occupancy state of an uplink buffer of the first relay node based on both uplink traffic waiting to be transmitted in the uplink buffer of the first relay node and a buffer occupancy percentage value received from a parent node.

[0123] Embodiment 7 is an apparatus according to embodiment 5, the processor being further configured to trigger generation of a message indicating a buffer occupancy status of an uplink buffer of the first relay node when a buffer status report is received from the second relay node.

[0124] Embodiment 8 is a device according to embodiment 5, wherein the processor is further configured to: when a buffer occupancy percentage value is received from a parent node, start a timer and write the buffer occupancy percentage value to a memory; when a new buffer occupancy percentage value is received from the parent node before the timer expires, restart the timer and overwrite the buffer occupancy percentage value in the memory with the new buffer occupancy percentage value; and when the timer expires, discard the buffer occupancy percentage value or a new buffer occupancy percentage value from the memory.

[0125] Embodiment 9 is the apparatus according to embodiment 8, wherein the timer is configured to expire after reaching a preconfigured timer duration value.

[0126] Embodiment 10 is the apparatus according to embodiment 8, the processor being further configured to receive a timer duration value from the parent node together with the buffer occupancy percentage value, wherein the timer is configured to expire after reaching the timer duration value.

[0127] Embodiment 11 is a device according to embodiment 1, wherein the processor is further configured to route a message indicating a buffer occupancy status of an uplink buffer of the first relay node to the second relay node based on a route of a data bearer for transmitting uplink traffic from the second relay node to the first relay node.

[0128] Embodiment 12 is the apparatus according to embodiment 11, the processor being further configured to communicate a message indicating a buffer occupancy status of an uplink buffer of the first relay node to the second relay node using an adaptation layer or a backhaul adaptation protocol layer of a wireless communication protocol.

[0129] Embodiment 13 is an apparatus according to embodiment 1, wherein determining that the first relay node is experiencing congestion in uplink transmissions comprises determining that an uplink buffer of the first relay node has reached or exceeded a predetermined occupancy level of uplink traffic awaiting transmission.

[0130] Embodiment 14 is a method for flow control in a first relay node including a first uplink buffer associated with a first buffer occupancy state, the method comprising: processing a first message from a second relay node indicating a second buffer occupancy state of a second uplink buffer of the second relay node; determining the first buffer occupancy state based at least in part on the second buffer occupancy state of the second uplink buffer of the second relay node and uplink traffic waiting to be transmitted in the first uplink buffer of the first relay node; and generating a second message for a third relay node, the second message including the first buffer occupancy state, wherein the third relay node is associated with the first relay node.

[0131] Embodiment 15 is a method according to embodiment 14, wherein determining the first buffer occupancy status also includes: processing a buffer status report from a third relay node indicating the amount of uplink data buffered at the third relay node; adding the amount of uplink data buffered at the third relay node to the uplink traffic waiting to be transmitted in the first uplink buffer of the first relay node; and subtracting the size of the uplink grant received from the second relay node at the first relay node from the uplink traffic waiting to be transmitted in the first uplink buffer of the first relay node.

[0132] Embodiment 16 is a method according to embodiment 14, wherein the second relay node is a parent relay configured to receive uplink traffic from the first relay node, and wherein the third relay node is a downlink node of the first relay node, so that the uplink traffic flows from the third relay node to the first relay node.

[0133] Embodiment 17 is a method according to embodiment 14, further comprising allocating uplink resources to the third relay node based on the first buffer occupancy status.

[0134] Embodiment 18 is a method according to embodiment 14, further comprising triggering generation of a second message when the first buffer occupancy status is equal to or greater than a predetermined occupancy level.

[0135] Embodiment 19 is a method according to embodiment 14, further comprising triggering generation of a second message in response to a buffer status report.

[0136] Embodiment 20 is a method according to embodiment 14, further comprising: when a second buffer occupancy status is received from a second relay node, starting a timer and writing the value of the second buffer occupancy status to a memory; when a new buffer occupancy status is received from the second relay node before the timer expires, restarting the timer and overwriting the value in the memory with a new value of the new buffer occupancy status; and when the timer expires, discarding the value or the new value from the memory.

[0137] Embodiment 21 is a method according to embodiment 20, wherein the timer is configured to expire after reaching a preconfigured timer duration value.

[0138] Embodiment 22 is a method according to embodiment 20, further comprising receiving a timer duration value from the second relay node in the first message, wherein the timer is configured to expire after reaching the timer duration value.

[0139] Embodiment 23 is a method according to embodiment 14, further comprising routing the second message to the third relay node based on a route of a data bearer used to transmit uplink traffic from the third relay node to the first relay node.

[0140] Embodiment 24 is a method according to embodiment 14, further comprising communicating the first message and the second message using an adaptation layer or a backhaul adaptation protocol layer of a wireless communication protocol.

[0141] Embodiment 25 is a method for flow control in a first relay node of a wireless communication network, the method comprising: determining that the first relay node is experiencing congestion in uplink transmission; and in response to determining that the first relay node is experiencing congestion in uplink transmission, generating a first message to a second relay node associated with the first relay node, the message indicating a buffer occupancy status of an uplink buffer of the first relay node.

[0142] Embodiment 26 is a method according to embodiment 25, wherein indicating a buffer occupancy status of an uplink buffer of the first relay node comprises indicating whether the uplink buffer occupancy is above a predetermined threshold.

[0143] Embodiment 27 is a method according to embodiment 25, further comprising: processing a second message from a parent node indicating a buffer occupancy percentage value of the parent node; and determining that the first relay node is experiencing uplink transmission congestion based at least in part on the buffer occupancy percentage value of the parent node.

[0144] Embodiment 28 is a method according to embodiment 27, further comprising: processing a buffer status report from the second relay node indicating the amount of uplink data buffered at the second relay node; and further determining that the first relay node is experiencing congestion in uplink transmission based on the buffer status report.

[0145] Unless explicitly stated otherwise, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise form disclosed. Modifications and variations are possible in view of the above teachings or may be obtained from the practice of the various embodiments.

[0146] It should be appreciated that the systems described herein include descriptions of specific embodiments. These embodiments may be combined into a single system, partially incorporated into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters / attributes / aspects, etc. of one embodiment may be used in another embodiment. For clarity, these parameters / attributes / aspects, etc. are described only in one or more embodiments, and it should be appreciated that unless otherwise stated herein, these parameters / attributes / aspects, etc. may be combined with or substituted for parameters / attributes, etc. of another embodiment.

[0147] Although the foregoing has been described in considerable detail for the sake of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways to implement both the processes and the apparatus described herein. Therefore, the embodiments of the present invention are to be regarded as illustrative rather than restrictive, and the description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Claims

1. An apparatus for flow control in a first relay node of a wireless communication network, the apparatus comprising: uplink buffer; and A processor, the processor being configured to: determining that the first relay node is experiencing uplink transmission congestion; as well as In response to determining that the first relay node is experiencing the congestion for uplink transmissions: A message is generated for a second relay node associated with the first relay node, the message comprising an expected buffer occupancy status of the uplink buffer of the first relay node, wherein the expected buffer occupancy status is based on an amount of buffered uplink data awaiting transmission to the first relay node.

2. The apparatus according to claim 1, wherein the processor is further configured to: In response to determining that the first relay node is experiencing the congestion for uplink transmissions: processing one or more buffer status reports received at the first relay node; determining a buffer occupancy value of the uplink buffer of the first relay node, the buffer occupancy value corresponding to uplink traffic waiting to be transmitted in the uplink buffer; as well as The buffer occupancy value is adjusted to calculate an expected buffer occupancy status of the uplink buffer of the first relay node by at least one of: increasing the buffer occupancy value based on an amount of buffered uplink data awaiting transmission to the first relay node as indicated in the one or more buffer status reports; as well as based on an uplink grant received at the first relay node, The buffer occupancy value is reduced.

3. The apparatus of claim 1 , wherein at least one of the one or more buffer status reports is from the second relay node, and wherein the second relay node is a downlink node of the first relay node, such that uplink traffic flows from the second relay node to the first relay node.

4. According to the device according to claim 1, the processor is also configured to route the message indicating the expected buffer occupancy status of the uplink buffer of the first relay node to the second relay node based on the routing of the data bearer used to transmit uplink traffic from the second relay node to the first relay node.

5. According to the device of claim 4, the processor is also configured to use an adaptation layer or a backhaul adaptation protocol layer of a wireless communication protocol to communicate the message indicating the expected buffer occupancy status of the uplink buffer of the first relay node to the second relay node.

6. The apparatus of claim 1, wherein determining that the first relay node is experiencing the congestion for uplink transmissions comprises determining that the uplink buffer of the first relay node has reached or exceeded a predetermined occupancy level of uplink traffic awaiting transmission.

7. A method for flow control in a first relay node of a wireless communication network, the first relay node comprising an uplink buffer, the method comprising: determining that the first relay node is experiencing uplink transmission congestion; as well as In response to determining that the first relay node is experiencing the congestion for uplink transmissions: A message is generated for a second relay node associated with the first relay node, the message comprising an expected buffer occupancy status of the uplink buffer of the first relay node, wherein the expected buffer occupancy status is based on an amount of buffered uplink data awaiting transmission to the first relay node.

8. The method according to claim 7, further comprising: In response to determining that the first relay node is experiencing the congestion for uplink transmissions: processing one or more buffer status reports received at the first relay node; determining a buffer occupancy value of the uplink buffer of the first relay node, the buffer occupancy value corresponding to uplink traffic waiting to be transmitted in the uplink buffer; as well as The buffer occupancy value is adjusted to calculate an expected buffer occupancy status of the uplink buffer of the first relay node by at least one of: increasing the buffer occupancy value based on an amount of buffered uplink data awaiting transmission to the first relay node as indicated in the one or more buffer status reports; as well as based on an uplink grant received at the first relay node, The buffer occupancy value is reduced.

9. The method of claim 7, wherein at least one of the one or more buffer status reports comes from the second relay node, and wherein the second relay node is a downlink node of the first relay node, so that uplink traffic flows from the second relay node to the first relay node.

10. The method of claim 7, further comprising routing the message indicating the expected buffer occupancy status of the uplink buffer of the first relay node to the second relay node based on a routing of a data bearer used to transmit uplink traffic from the second relay node to the first relay node.

11. The method of claim 10, further comprising communicating the message indicating the expected buffer occupancy status of the uplink buffer of the first relay node to the second relay node using an adaptation layer or a backhaul adaptation protocol layer of a wireless communication protocol.

12. The method of claim 7, wherein determining that the first relay node is experiencing the congestion for uplink transmissions comprises determining that the uplink buffer of the first relay node has reached or exceeded a predetermined occupancy level of uplink traffic awaiting transmission.

13. At least one non-transitory computer-readable storage medium comprising computer-readable instructions stored thereon for flow control in a first relay node of a wireless communication network comprising an uplink buffer, the computer-readable instructions configured to teach one or more processors to: determining that the first relay node is experiencing uplink transmission congestion; and In response to determining that the first relay node is experiencing the congestion for uplink transmissions: A message is generated for a second relay node associated with the first relay node, the message comprising an expected buffer occupancy status of the uplink buffer of the first relay node, wherein the expected buffer occupancy status is based on an amount of buffered uplink data awaiting transmission to the first relay node.

14. The at least one non-transitory computer-readable storage medium of claim 13, wherein the computer-readable instructions are further configured to: In response to determining that the first relay node is experiencing the congestion for uplink transmissions: processing one or more buffer status reports received at the first relay node; determining a buffer occupancy value of the uplink buffer of the first relay node, the buffer occupancy value corresponding to uplink traffic waiting to be transmitted in the uplink buffer; as well as The buffer occupancy value is adjusted to calculate an expected buffer occupancy status of the uplink buffer of the first relay node by at least one of: increasing the buffer occupancy value based on an amount of buffered uplink data awaiting transmission to the first relay node as indicated in the one or more buffer status reports; as well as based on an uplink grant received at the first relay node, The buffer occupancy value is reduced.

15. At least one non-transitory computer-readable storage medium according to claim 13, wherein at least one buffer status report of the one or more buffer status reports comes from the second relay node, and wherein the second relay node is a downlink node of the first relay node, so that uplink traffic flows from the second relay node to the first relay node.

16. At least one non-transitory computer-readable storage medium according to claim 13, wherein the computer-readable instructions are also configured to route the message indicating the expected buffer occupancy status of the uplink buffer of the first relay node to the second relay node based on the routing of the data carrier used to transmit uplink traffic from the second relay node to the first relay node.

17. At least one non-transitory computer-readable storage medium according to claim 16, wherein the computer-readable instructions are also configured to use an adaptation layer or a backhaul adaptation protocol layer of a wireless communication protocol to communicate the message indicating the expected buffer occupancy status of the uplink buffer of the first relay node to the second relay node.

18. At least one non-transitory computer-readable storage medium according to claim 13, wherein determining that the first relay node is experiencing the congestion in uplink transmissions comprises determining that the uplink buffer of the first relay node has reached or exceeded a predetermined occupancy level of uplink traffic awaiting transmission.

Images