Communication system, device and method for operation in FDD networks

Abstract

A communication system (300, 400, 600), arranged to use frequency division duplex, FDD, communications, comprises a centralised processing unit, CU (540); a donor node (610), operably coupled to the CU (540); a plurality of child nodes, CNs (500), where at least one child node (615) is operably coupled to the donor node (610); and a plurality of user endpoints, UE (450-456, 620-625, 670-675). The CU (540) is operably coupled to a CN and UE activity processing circuit (530) located in a CN (615, 665) of the plurality of CNs. The CN and UE activity processing circuit (530) is configured to determine a level of traffic in the communication system that is supported by the CN (615, 665). The CU (540) is configured to instruct the CN (615, 665) to transition between an active mode of operation and an idle mode of operation in response to the determined level of traffic.

Description

COMMUNICATION SYSTEM, DEVICE AND METHOD FOR OPERATION IN FDDNETWORKSTechnical Field

[0001] The technical field relates generally to a system, communication device and method for efficient operation in Frequency Division Duplex (FDD) networks. In particular, in some examples, the technical field relates to an energy-efficient operation in fifth generation (5G) Integrated Access Backhaul (I AB FDD) networks.Background

[0002] In recent years, third generation (3G) wireless communications have evolved to the longterm evolution (LTE™) cellular communication standard, sometimes referred to as 4thgeneration (4G) wireless communications. Both 3G and 4G technologies are compliant with third generation partnership project (3 GPP™) standards. 4G networks and phones were designed to support mobile internet and higher speeds for activities, such as video streaming and gaming.The 3 GPP™ standards are now developing a fifth generation (5G) of mobile wireless communications, which is set to initiate a step change in the delivery of better and faster data rate communications, for example powering businesses, improving communications within homes and spearheading advances such as driverless cars.

[0003] One of the potential technologies targeted to enable future cellular network deployment scenarios and applications is the support for wireless backhaul and relay links that enable flexible and very dense deployment of 5G-new radio (NR) cells without a need for densifying the transport network proportionately.

[0004] In a traditional 5G communication pathway, a user device will send data via a wireless communication link to a 5G enabled mast, which decodes the data before forwarding it to the next step of the pathway. Often this next step is direct to a routing device, which may be at the IP layer, another telecommunication pathway (e.g., 4G or satellite phone) or may involve reencoding and sending on another 5G pathway. The 3GPP specification 38.174 provides aAttorney Docket No. JET 2024-003 WO Specification Final mechanism for a 5G enabled masts to pass on the data to another 5G enabled mast within radio range, without requiring the full decoding and encoding at every step, referred to as ‘Integrated Access and Backhaul’ (IAB). One of the main features of IAB is the introduction of the Backhaul Adaptation Protocol (BAP), which includes additional information appended to radio data to indicate which 5G node (often the UE) that the data is intended for and which 5G node the data originated from. It is known that IAB has been designed to offer two forms of communication, frequency division duplex (FDD), which employs two frequency bands (in radio frequency (RF) terms) and time division duplex (TDD). It is known that supporting FDD requires more hardware and frequency spectrum, but facilitates constant communication. In contrast, TDD requires less hardware, but requires quiet periods in the timing structure for use by the other device.

[0005] Due to the expected larger bandwidth available for NR, as compared to long term evolved (LTE™) (e.g., mmWave spectrum) along with the native deployment of massive multiple-in / multiple-out (MIMO) or multi-beam systems in NR, it is envisaged that development and deployment of IAB communication links will continue to be very popular. It is envisaged that this may allow easier deployment of a dense network of self-backhauled NR cells in a more integrated manner, by building upon many of the control and data channels / procedures defined for providing access to UEs.

[0006] Referring now to FIG. 1, a simplified block diagram of a known 5G base station 100 capable of supporting IAB is illustrated. The 5G base station 100 (often referred to as a gNodeB (gNB)), includes hardware 150 functionality and software 105 functionality. The 5G base station 100 is configured to communicate with another communication network and other 5G base stations and wireless communication devices, such as user equipment (UEs). In this illustration, the software 105 functionality includes four functions, referred to as: Centralized Unit (CU) 120 and IAB Distributed Unit (DU) 115 and a Radio Unit (RU) 110. In some examples, the CU 120 provides support for the higher layers of the protocol stack such as Service Data Adaption Protocol (SDAP), Packet Data Convergence Protocol (PDCP) and Radio Resource Control (RRC) whilst, the DU 115 provides support for the lower layers of the protocol stack such as Radio Link Control (RLC) and Medium Access Control (MAC) layers, whereas the RU 110,Attorney Docket No. JET 2024-003 WO Specification Final sometimes referred to as radio head, is configured to handle the Physical layer of communications in the protocol stack. The 5G base station 100 also includes a 5G core 125, in essence network gateway software that fundamentally controls the network's operation. The 5G core 125 is configured to provide signalling control (such as user authentication and data session creation and tear-down and typically known as the ‘Control Plane’), plus transport of data across those sessions (typically known as the ‘User Plane’). Time synchronization data distribution 117 is passed between the DU 115 and the CU 120, where the dashed line indicates that the DU 115 may or may not be co-located with the CU 120. Network-wide time synchronization data 122 is passed between the CU 120 and the 5G core 125, where the dashed line indicates that the 5G core 125 may or may not be co-located with the CU 120. It is known that for the IAB FDD network all data for a node and its children are sent via a donor node.

[0007] The hardware 150 functionality a field programmable gate array (FPGA) device with a software defined radio (SDR) card 160, which performs signal processing and timing capture. A single board computer 170 (i.e., a primary computing platform) is connected 162 to the FPGA with SDR card 160. The single board computer 170 is connected to the 5G core 125 via a hardware-software interface 172. The FPGA with SDR card 160 provides synchronization data 164 to the 5G core 125, timing adjustments data 166 to the DU 115 and time-stamped RF data 168 to the RU 110. For IAB, there is the additional user equipment / endpoint ‘UE’ (not included in FIG. 1). For IAB FDD, the MT node (referred to as ‘CN’ node in later paragraphs) consists of DU (115), UE, two RUs (110).

[0008] Referring now to FIG. 2, a known traditional IAB FDD network 200 is illustrated where all nodes are active. Currently, an IAB network must be set up as a singly-connected tree; that is, any given node (often a base station) can only contain a maximum of a single parent node. If a node contains no parents, then that is the donor node 210 (e.g., the trunk of the tree) and it is connected to a routing device (not shown) for forwarding to another network. It is also known that any node may also have child nodes (e.g., other 5G base stations), e.g., IAB child nodes 215 each have a single parent node (i.e., IAB donor node 210) and connections 225 to 5GUser Endpoint (UE) 220 devices. Similarly, as shown it is also known that donor node 210 may be directly connected 227 to one or more 5G User Endpoint (UE) 220 devices. It is known that theAttorney Docket No. JET 2024-003 WO Specification Final control mechanism for the IAB FDD network may be situated on the donor node 210 or externally, with all data for a node and its children being sent via the donor node 210. The underlying connection mechanism between a node and any children (another node, or UE) is as defined by the 3 GPP standards for 5GNR.

[0009] It is known that the flow of data is always up or down the network; with up being from user Endpoint 220, 222 to the donor node 210, and down being from the donor node 210 to the user Endpoint 220, 222 (or child 5G node). Notably, there is no direct sideways communication, with data that is between two devices within the network still having to go up to the donor node 210 before being sent back down to the relevant user Endpoint 220, 222. It is known that a single point-to-point (P2P) exists in an uplink direction, but that point to multi-point (P2MP) exists in a downlink direction, albeit that all traffic passes to the root node (i.e., the donor node 210 in the illustrated example) before being routed (if necessary) back to a child node (even if there is a common node in the tree before the root node). This arrangement allows for any uplink data to be blindly forwarded on to the next parent node, and ultimately the donor node 210. For downlink data, however, every node has to decode the backhaul adaptation protocol (BAP) information in order to determine whether the radio data is intended for a local node, or whether the whole set of BAP information and radio data is to be forwarded to a known child node.However, and notably, it is only when a 5G node has fully decoded the radio data that it is able to determine whether the radio data is for an intended local node.

[0010] The inventors have recognised and appreciated that in existing In-Band Full-Duplex (IAB FDD) networks, all child nodes (CNs) remain active irrespective of actual UE presence, which they have identified leads to inefficiencies. Such inefficiencies of the current FDD methodology include constant power consumption, as CNs remain active even when no UE is within range, thereby resulting in unnecessary energy use. Such inefficiencies of the current FDD methodology include increased network congestion and interference, due in main as a result of the continuous operation of CNs, which contributes to inter-cell interference, thereby reducing overall network performance. The inventors have also recognised and appreciated that the current approach in FDD is to have a rigid network resource allocation, which is limiting and is not related to real-time demand. Thus, this leads to inefficient use of spectrum and power. TheAttorney Docket No. JET 2024-003 WO Specification Final inventors have also recognised and appreciated that the current approach in FDD causes latency problems. Since all CNs are always active, the network does not prioritize node activations based on UE mobility patterns, thereby resulting in suboptimal resource scheduling.

[0011] There is therefore a need system, communication device and method for efficient operation in Frequency Division Duplex (FDD) networks that mitigates some of the aforementioned inefficiencies.SummaryA communication system, a child node (such as a base station) a centralised processing unit and a method of communication, for example Frequency Division Duplex (FDD) communications, are described, as clarified in the accompanying claims.Brief Description of the Drawings

[0012] Further details, aspects and embodiments will be described, by way of example only, with reference to the drawings. In the drawings, similar reference numbers are used to identify like, or functionally similar, elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.FIG. 1 illustrates a simplified block diagram of a known 5G base station that supports IAB.FIG. 2 illustrates a known traditional IAB FDD network.FIG. 3 illustrates a simplified 5G architecture configured to support IAB, according to some example embodiments.FIG. 4 illustrates a layered view of a IAB FDD network with a novel two frequency approach, according to some example embodiments.FIG. 5 illustrates a simplified block diagram of one example of a 5GIAB base station (or node), according to some example embodiments.Attorney Docket No. JET 2024-003 WO Specification FinalFIG. 6 illustrates a layered view of an IAB FDD network, using the proposed dynamic node activation mechanism, with idle-to-active CN transitions and an adaptive scheduling strategy for active and idle CNs, in accordance with some example embodiments.FIG. 7 illustrates a simplified flowchart of an IAB FDD network using the novel alternating two frequency approach between parent and child nodes, in accordance with some example embodiments.

[0013] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and / or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments herein-described. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various example embodiments. It will be further appreciated that certain actions and / or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have their ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.Detailed Description

[0014] Examples described herein provide an energy-efficient mechanism for dynamic node activation in IAB FDD networks. In particular, by leveraging UE-driven wake-up signalling, adaptive scheduling, and cluster-based node management, an IAB FDD network ensures optimal power consumption without compromising coverage. Examples described herein enhance IAB FDD network efficiency through dynamic node activation, where CNs are configured to transition between ‘active’ and ‘idle’ states based on UE presence. Thus, in some examples, a mechanism for the network to dynamically activating and / or deactivating child nodes (CNs) is introduced based on user equipment (UE) presence, thereby reducing power consumption while maintaining network coverage. For example, a combination of the CN and the CU performs theAttorney Docket No. JET 2024-003 WO Specification Final actions described herein, where the CU will determine what is best for the network as a whole, whereas the CN will enact that action.

[0015] Generally, in known systems, the nodes are configured to always be in an ‘active state’ with a set range / transmission power. However, in some examples described herein, a CU implements a method whereby CNs are configured to dynamically switch between being in an ‘active’ state and an ‘idle’ state based on UE activity. In particular, the CNs are configured to dynamically switch between being in an ‘active’ state and an ‘idle’ state, based on UE proximity and traffic (referred to herein as UE proximity-based activation). In some examples, seamless UE connectivity may be achieved using proximity-based wake-up signals and adaptive FDD scheduling, thereby ensuring low-latency transitions between idle and active states. In this regard, the network is arranged to determine whether (or not) a high level of UE traffic exists for neighbouring nodes of an Idle CN. In response to a high level of UE traffic exists for neighbouring nodes of an Idle CN, the network (e.g., a CU of a base station) signals for the idle CN to re-activate and establish a modified coverage area. In some examples, the transmission scheduling of the CNs is reconfigured (by the CU) in response to a determined high level of UE traffic exists for neighbouring nodes of an idle CN. The original trigger is that the CU registers high traffic usage in the neighbouring, active CNs, and then signals for the idle CN to become active. Here, active CNs are configured to increase their transmission range when adjacent CNs are idle in order to maintain seamless network coverage. In some examples, scheduling algorithms configured by the CU of a base station and implemented by the idle CN ensure minimal latency in CN wake-up transitions. In some examples, the CNs are configured to optimize node activity and power usage by transitioning to idle mode, thereby extending an overall network infrastructure lifespan.

[0016] However, in examples herein described, CNs with a low-level of or no UE activity (i.e., no UEs are detected) for a predefined period, the network ensures that CNs enter a low-power idle mode having reduced power. In this manner, a significant reduction in power consumption may be achieved. For example, if an 'average' UE traffic is low in a particular geographical area, then a CN may be removed and the geographical area covered by neighbouring CNs being (re- )configured with an extended range to support such an additional low-level of UE traffic. In some examples, the CNs are configured to implement a layer-based activation strategy in response to a determination that a high level of UE traffic exists for neighbouring nodes of anAttorney Docket No. JET 2024-003 WO Specification Final idle CN. In this manner, CNs are organized as a mesh with overlapping coverage zones that allow for at least every other CN to enter into an idle mode whilst preserving continuous coverage, and thereby improving energy efficiency.

[0017] Advantageously, implementing one or more of the examples described herein reduces energy consumption in the network, as CNs are active only when needed, thereby minimizing power usage. Furthermore, implementing one or more of the examples described herein optimizes network resource allocation, as the network ensures CNs only become active when required, as the CNs mode of operation is dynamically adjusted based on UE presence, thereby enhancing spectral efficiency and network capacity. Additionally, implementing one or more of the examples described herein provides seamless maintenance of network coverage, as active CNs are configured by the CU of a base station to compensate for idle CNs, without degrading connectivity. Beneficially, by limiting the number of active CNs, examples herein described mitigate or reduce inter-cell interference, leading to higher signal quality as fewer CNs are active.

[0018] Referring now to FIG. 3, a simplified 5G architecture 300 is configured to support an Integrated Access and Backhaul (IAB) network. Here, a first 5G base station 322 is operably connected to the base station with IAB capability, preferably with secure communications. The first 5G base station 322 supports communications within a coverage area 324, including communication support for a plurality of mobile (or fixed) wireless communication units, sometimes referred to as a terminal device, such as a user equipment UE 326. In 5G, the UE 326 is able to support traditional Human Type Communications (HTC) or the new emerging Machine Type Communications (MTC). The simplified 5G architecture 300 includes a second 5G base station 312 supporting communications within a coverage area 314, including communication support for a plurality of mobile (or fixed) wireless communication units, such as UE 316. A wireless backhaul connection 333, generally an Xn (based on X2) interface connects the first 5G base station 322 with the second 5G base station 312. The first 5G base station 322 is also connected to the core network via a more traditional wired connection, such as fibre 334.

[0019] In this regard, in an IAB scenario, the base station with IAB capability is considered a donor IAB node and node A (i.e., first 5G base station 322) together with node C (i.e., second 5GAttorney Docket No. JET 2024-003 WO Specification Final base station 312) are identified as relay IAB nodes. Thus, in this manner, a meshed network is able to support communications between communication devices in a hostile location (for example that did not have any recognizable communication) and a civilian (or military) communication system 300.

[0020] Although examples are described herein with respect to a 5G implementation, it is envisaged that the concepts are equally applicable to 6G systems and many other communications systems that use backhaul techniques.

[0021] Referring now to FIG. 4, a layered view of an IAB FDD network 400 with a novel two frequency approach is illustrated, according to some example embodiments. The IAB FDD network 400 includes a donor node 410 that is configured to individually and respectively communicate with a plurality of base stations 420, 421, 422 in a first layer, and (in this example) two user endpoints 450, 451 using a first frequency Fl (of at least a two-frequency approach). Notably, in accordance with some examples, the plurality of base stations 420, 421, 422 in the first layer, are configured to individually and respectively communicate with a further plurality of base stations 430, 431, 432, 433 in a second layer, and (in this example) two further user endpoints 452, 456 using a second frequency F2 (of at least a two-frequency approach). As illustrated, transitioning between layers alternates which frequency is used.

[0022] Again, as illustrates, the further plurality of base stations 430, 431, 432, 433 in a second layer are configured to individually and respectively communicate with a yet further base station 440 in a third layer, and (in this example) a further two user endpoints 453, 455 using a first frequency Fl again (of at least a two-frequency approach). As illustrated, transitioning between layers again alternates which frequency is used. Thus, thereafter, when the yet further base station 440 in the third layer communicates with a still yet further user endpoint 454, the second frequency F2 is again used.

[0023] Thus, in the example in FIG. 4, each set (inter-layer) of communications is run using the 3GPP standardised 5G protocols. However, in this example, a use of two alternating frequencies ensures that every layer of communication can run independently, giving processing and bandwidth as associated with a single non-IAB connection. In order to determine whether the data is upward bound, or downward bound, without doing any additional decoding, someAttorney Docket No. JET 2024-003 WO Specification Final examples described herein ensure that a 5G node is able to identify whether the information being received is from a parent node (i.e., downward data) or a child node (upward data) via some other means. For example, for FDD IAB and if the signal is on the downlink frequency, then it is from the child node (going upward); whereas if the signal is on the uplink frequency, then it is from the parent node (going downward). This imposes a spatial limitation, which results in a layered mesh, as discussed earlier. In this example, by using two separated frequencies within the 5G bands, it is possible for any given node to have a parent using one frequency, and any children on the second frequency. In some examples, it is recommended that the two separated frequencies (i.e., two frequency ‘ranges’ supporting multiple distinct communication frequencies) may be non-over-lapping. In some other examples, it is envisaged that the two separated frequencies may have some overlap that orthogonal frequency division multiple algorithms will be able to handle. Using this setup, an IAB network must use a minimum of two frequencies, with the frequency associated with the parent and that associated with the children alternating with each layer of the network (as shown). When using two frequencies in close (geographical) proximity, care must be taken to reduce interference between the two transmissions. In some examples, this may include physically changing the geometry (by modifying the distance between the two transmitters within the base station), and / or constraining the transmission to certain directions and / or using frequencies sufficiently separated in the spectrum that they do not interfere.

[0024] Referring now to FIG. 5, a block diagram of a 5G base station 500, which in some examples may support IAB, is illustrated adapted in accordance with some example embodiments. In some examples, it is envisaged that the central processing hub 260 may be of a similar architecture to the 5G base station 500 of FIG. 5, as would be understood by a skilled artisan. In some examples, the 5G base station 500 may be simplified to function as a repeater, without the suite of control functions that are contained in a fully-functional base station. The 5G base station 500 contains an antenna array 502, for receiving transmissions, coupled to an antenna switch 504 that provides isolation between receive and transmit chains within the 5G base station 500. One or more receiver chains, as known in the art, include receiver RF front-end (RFFE) circuitry 506 (effectively providing reception, filtering and intermediate or base-band frequency conversion). The receiver front-end circuitry 506 is coupled to a signal processingAttorney Docket No. JET 2024-003 WO Specification Final module 508 (generally realized by a digital signal processor (DSP)). A skilled artisan will appreciate that the level of integration of receiver circuits or components may be, in some instances, implementation-dependent.

[0025] The controller 514 maintains overall operational control of the 5G base station 500. The controller 514 is also coupled to the receiver RFFE circuitry 506 and the signal processing module 508. In some examples, the controller 514 is also coupled to a frequency generation circuit 517 and a memory device 516 that selectively stores operating regimes, such as decoding / encoding functions, synchronization patterns, code sequences, and the like. A timer circuit 518 is operably coupled to the controller 514 to control the timing of operations (e.g., transmission or reception of time-dependent signals) within the 5G base station 500. In accordance with examples described herein, the timer circuit 518 is responsive to control signals issued by the controller 514 to adjust the timing of operations in the 5G base station 500 according to the concepts described herein.

[0026] As regards the transmit chain, this essentially includes an input circuit 520 configured to receive information from one or more sensors connected to signal processor 508. In some examples, the one or more sensors may include at least a sensed temperature to detect external influences on a local clock (i.e., in a timer circuit 518). The signal processor 508 is coupled in series through transmitter / modulation circuitry 522 and a power amplifier 524 to the antenna array 502, which in some examples comprises a plurality of antenna arrays that are configured as a steerable beam-forming antenna. The transmitter / modulation circuitry 522 and the power amplifier 524 are operationally responsive to the controller 514. In accordance with some example embodiments, the signal processor 508 and transceiver (e.g., transmitter / modulation circuitry 522) of the 5G base station 500 may be configured to communicate with another 5G base station.

[0027] The signal processor 508 in the transmit chain may be implemented as distinct from the signal processor in the receive chain. Alternatively, a single processor may be used to implement a processing of both transmit and receive signals, as shown in FIG. 5. Clearly, the various components within the 5G base station 500 can be realized in discrete or integrated component form, with an ultimate structure therefore being an application-specific or design selection.Attorney Docket No. JET 2024-003 WO Specification Final

[0028] In some examples, the signal processor 508 is coupled to an antenna beam-form controller 535 ensures that adjustments are made to the antenna array / antenna elements in a timely manner, thereby aligning the antenna and timing circuits for optimal communication. These adjustments optimize signal transmission and reception, ensuring synchronization and efficient communication between base station.

[0029] In accordance with examples described herein, a CU 540 is operably coupled to signal processor 508 and is configured to implement a method whereby CNs are configured to determine how busy a particular CN is, e.g., how active it is and how many child node and / or UE communications that it is currently actively supporting. In some examples, it is envisaged that the CU 540 may be configured to determine a level of traffic in the communication system that is supported by the CN by using one or more thresholds to decide whether the CN is ‘busy’ state or in a ‘reasonable / average’ level of communication support state or in a ‘quiet’ state. In this manner, the CU 540 may compare a determined level of traffic in the communication system that is supported by the CN to one or more threshold levels of traffic. Thus, an instruction to the CN to transition between an ‘active’ mode of operation and an ‘idle’ mode of operation may be in response to the comparison of the determined level of traffic with the threshold level of traffic.

[0030] In some examples, the CU 540 is directly connected to a donor DU only. It is envisaged that the CU 540 may be located on the same hardware, or it may be connected to the donor DU via a network connection (as illustrated in FIG. 5. Thus, and notably, messages are transferred from the CU to the CN with no modification in between from any intermediary devices. However, the messages between the CU and CN are transmitted over the network and so go via the donor node and any other child node between the CU and the CN (with no processing of the message other than to pass it to the next intermediary device).

[0031] In accordance with examples described herein the CU 540 configures a CN to dynamically switch between being in an ‘active’ state and an ‘idle’ state based on an identified low-level of child node and UE activity, assessed in child node and UE activity processing circuit 530. In particular, in one example, the CNs are configured to dynamically switch between being in an ‘active’ state and an ‘idle’ state based on child node and UE proximity as identified by child node and UE proximity determination circuit 532. In this regard, the network, for example UE traffic assessment circuit 534 is arranged to determine whether (or not) a high levelAttorney Docket No. JET 2024-003 WO Specification Final of UE traffic exists for neighbouring nodes of an idle CN. In response to determining that a high level of UE traffic exists for neighbouring nodes of an idle CN, the network (e.g., a CU 540 of the or a base station) signals for the idle CN to re-activate and establish a modified coverage area.

[0032] In some examples described herein CU 540 implements a method whereby such CNs are configured to dynamically switch between being in an ‘active’ state and an ‘idle’ state based on UE activity, as well as implement a more effective FDD scheduling scheme. In particular, the CNs are configured to dynamically switch between being in an ‘active’ state and an ‘idle’ state, based on UE proximity and determined levels of traffic (referred to herein as UE proximitybased activation). In some examples, seamless UE connectivity may be achieved using proximity-based wake-up signals and adaptive FDD scheduling, thereby ensuring low-latency transitions between idle and active states. In this regard, the CU 540 is arranged to determine whether (or not) a high level of UE traffic exists for neighbouring nodes of an idle CN. In response to determining that a high level of UE traffic exists for neighbouring nodes of an idle CN, the network (e.g., CU 540 of the base station) signals for the idle CN to re-activate and establish a modified coverage area. In some examples, the transmission scheduling of the CNs is re-configured (by the CU 540) in response to a determined high-level of UE traffic existing for neighbouring nodes of an idle CN. The trigger is that the CU 540 registers high traffic usage in the neighbouring, active CNs, and then signals for the idle CN to become active again, to assist in handling the traffic load at that time. When an idle CN becomes active again, other active CNs are configured to decrease their transmission range to accommodate the recently active CN, thereby saving power and in order to maintain seamless network coverage. In some examples, FDD scheduling algorithms configured by the CU 540 of the base station and implemented by the idle CN ensure minimal latency in CN wake-up transitions.

[0033] Similarly, in other examples, the CU 540 is arranged to determine whether (or not) a low- level of UE traffic (or no traffic) exists for an active CN that has neighbouring nodes for a predefined period. In response to determining that a low-level of UE traffic exists for the active CN that has neighbouring nodes, the network (e.g., a CU 540 of a base station) signals for the active CN to transition to an idle mode. In this manner, a significant reduction in power consumption may be achieved. Additionally, in this manner, an active CN may acquire one or more CN or UE communications from the CN that has transitioned from an active mode to anAttorney Docket No. JET 2024-003 WO Specification Final idle mode (as shown in FIG. 6). Furthermore, in this manner, the CU 540 may instruct neighbouring CNs to increase their power for them to establish a modified coverage area that accommodates the loss of coverage area relinquished by the CN that has transitioned from an active to an idle mode state, i.e., provide an extended range to support such an additional low- level of UE traffic. Thus, in some examples, the CNs are (re-)configured to optimize node activity and power usage by transitioning between active mode and an idle mode, thereby extending an overall network infrastructure lifespan.

[0034] In some examples, the CNs are configured to implement a layer-based activation strategy in response to a determination of a high-level or low-level of UE traffic. In this manner, CNs may be organized as a mesh with overlapping coverage zones that allow for at least every other CN to enter into an idle mode whilst preserving continuous coverage, and thereby improving energy efficiency.

[0035] In some examples, the signal processor 508 (connected to the CU 540) includes a CN state determination circuit 536 arranged to determine and / or track an operational state of CN’s attached to the base station. In some examples, the CNs are configured to perform adaptive transmission FDD scheduling with transmitter 522 and power amplifier 524, in response to a determined high-level or low-level of UE traffic. In some examples, the CNs are configured to implement a layer-based activation strategy, as illustrated in FIG. 4 and FIG. 6. In some examples, it is envisaged that CNs may be organized in layers with overlapping coverage zones, thereby allowing for at least every other CN to enter into an idle mode whilst preserving continuous coverage, and thereby improving energy efficiency. By overlapping coverage zones, there is redundancy so that a CN can be removed and the remaining CNs reconfigured to provide the full coverage, if there is a low-level of traffic, thereby maintaining signal coverage for the entire area. By reducing the number of CNs that are active, there is an improved energy efficiency. In some examples, it is intended to waken the idle CN using the UE IDLE mode functionality (described in 3GPP standard); so if the MT-UE is in IDLE mode, then the DU stops transmitting.

[0036] In some examples, it is envisaged that the signal processor 508 may include or be operably coupled to, accurate timing, such as a GNSS or GPS circuit. In this manner, it is envisaged that the CN is able to obtain an accurate location of itself, which it is able to send toAttorney Docket No. JET 2024-003 WO Specification Final the CU 540. With accurate location information for each CN, the CU 540 is able to use the location information to know whether other CNs are able to cover communications for a CN that is to be re-configured as an idle CN.

[0037] Referring now to FIG. 6, a layered view 600 of an IAB FDD network is illustrated, where a first overview of a IAB FDD network shows that it is busy 605 and where all child nodes (CNs) are active, and a second overview of the IAB FDD network shows that it is less busy 655 (which may be referred to as a ‘quiet state’ where dynamic node activation is in progress), whereby some nodes are active, but in this example one CN 670 is re-configured to be idle, due to a determination (by a CU, connected to a DU on the donor node 610) that the network is quiet and / or the CN node 670 is not supporting many communications to other (parent or child) CNs or UEs. The second overview of the IAB FDD network showing that it is less busy 655 proposes a dynamic node activation mechanism, whereby an active CN 670 transitions to being an idle CN, in accordance with some example embodiments.

[0038] The donor node 610 contains no parents and is connected to a routing device (not shown) for forwarding communications to another network. When the network is determined as being ‘busy’ (i.e., the first overview of a IAB FDD network shows that it is busy 605), the donor node 610 has child nodes (e.g., other 5G base stations functioning as IAB child nodes) 615, 616 and 617 each having a single parent node (i.e., IAB donor node 610). As shown in this example, each child node (e.g., other 5G base stations functioning as IAB child nodes) 615, 616 and 617 have their own child nodes which in this case are respective 5G User Endpoint (UE) devices 620, 621, 622.

[0039] When the network is determined as being ‘quiet’ (i.e., in the second overview of the IAB FDD network shows that it is less busy 655), a CU determines that one CN 670 may be reconfigured to be idle, due to a determination by the CU that the network is quiet and / or the CN node 670 is not supporting many communications to other (parent or child) CNs or UEs. IN this manner, the CU proposes a dynamic node activation mechanism, whereby the active CN 670 transitions to being an idle CN, in accordance with some example embodiments. In this regard, the CU may then instruct other CNs to increase their power and coverage area, such that active CN 655 can then communicate with UE 681 as well as previous UE 680.Attorney Docket No. JET 2024-003 WO Specification Final

[0040] It is envisaged that the above operation can equally work in reverse, with a CN transitioning from an idle node / state to an active node / state when the network is determined as being ‘busy’ (i.e., the first overview of a IAB FDD network shows that it is busy 605).

[0041] The underlying connection mechanism between a node and any children (another node, or UE) is as defined by the 3GPP standards for 5G NR.

[0042] The flow of data is always up or down the network; with up being from user Endpoint 620 to the donor node 610 (which may be via active IAB child node 617), and down being from the donor node 610 to the user Endpoint 620 (or child 5G node) (again, which may be via active IAB child node 617). Notably, there is no direct sideways communication, with data that is between two devices within the network still having to go up to the donor node 610 before being sent back down to the relevant user Endpoint 620. It is known that a single point-to-point (P2P) exists in an uplink direction, but that point to multi-point (P2MP) exists in a downlink direction, albeit that all traffic passes to the root node (i.e., the donor node 610 in the illustrated example) before being routed (if necessary) back to a child node (even if there is a common node in the tree before the root node). This arrangement allows for any uplink data to be blindly forwarded on to the next parent node, and ultimately the donor node 610. Notably, in accordance with examples described herein, downlink data no longer has to be decoded fully in every node. Here, a 5G node only has to be able to identify whether the information is received from a parent node (i.e., downward data) or a child node (upward data) via some other means.

[0043] Referring now to FIG. 7, a simplified flowchart 700 of an IAB FDD network using the novel alternating two frequency approach between parent and child nodes is illustrated, in accordance with some example embodiments. At 702, a CU (such as CU 540 in FIG. 5) monitors active CN activity and UE traffic in the network, and determines whether individual CNs are ‘busy’ or ‘quiet’. At 704, if the CU determines UE traffic is ‘busy’, the CU determines whether (or not) to re-activate a potential idle CN, for example dependent on a determined number of proximate UEs. At 706, if the CU determines that an ‘idle’ CN may assist the busy UE traffic, the CU re-activates the idle CN, and implements a FDD scheduling scheme (according to FIG. 6). In response thereto, at 708, the CU may also instruct other CNs to reduce their signal powerAttorney Docket No. JET 2024-003 WO Specification Final and associated coverage area to facilitate the coverage provided by the re-activated CN handing traffic.

[0044] However, at 710 and if the determined UE traffic is ‘quiet’ at 702, the CU determines whether (or not) to de-activate an active CN, i.e., move it to idle mode, for example dependent on a determined number of proximate UEs. At 712, if the CU determines that transitioning an ‘active’ CN to an ‘idle’ mode may save energy, the CU initiates the CN transition, and adapts a FDD scheduling scheme. In response thereto, at 714, the CU may also instruct other CNs to increase their signal power and associated coverage area to facilitate the coverage lost to the deactivated CN.

[0045] When comparing the aforementioned FDD approach, with a comparable (but different) TDD approach, it is noted that one difference between the FDD approach and the TDD approach in terms of algorithmic software that is applied is that TDD may require an entire reconfiguration of 'routing' (for example as in some instances it may be considered to equate to a full mesh) due to new layers being formed (or removed), whereas an FDD approach will remain with the same number of layers, as illustrated in FIG. 6, so is less likely to impact the routing. Furthermore, a skilled artisan will appreciate that TDD does not required a specific combinations of frequencies, as compared to the aforementioned FDD approach that requires two separated frequencies. Additionally, a skilled artisan will appreciate that FDD requires each CN to have the correct combination of frequencies for communicating uplink and downlink, which limits those CNs that can become children of a parent node. In contrast, TDD does not require this combination, and therefore it is envisaged that TDD may be better for moving networks (thereby allowing CNs to change parents). Similarly, it is envisaged that an FDD solution may, in some instances, be better for fixed base station solutions.

[0046] In some alternative examples, it is envisaged that the FDD concepts herein described may be employed in isolation of the UE traffic monitoring approach. In this context, it is envisaged that a communication system is arranged to use frequency division duplex, FDD, communications, and comprises: a centralised processing unit, CU 540; a donor node (such as donor node 610), operably coupled to the CU 540; a plurality of child nodes, CNs, where at least one child node is operably coupled to the donor node; and a plurality of user endpoints, UE. In this alternative example, the CU 540 is operably coupled to a CN via a donor node (andAttorney Docket No. JET 2024-003 WO Specification Final potentially one or more further CNs and / or UEs. In this alternative example, the CU (such as CU 540) is configured to alternate use between two frequencies of a frequency division duplex, communications scheme between the donor node and at least one of the plurality of user endpoints, UE via the at least one CN. In this alternative example, the plurality of CNs may be arranged to form communication ‘layers’ between the at least one child node and the donor node. The CU 540 is configured to alternate a use between the two frequencies, between successive layers, in communications between the donor node and at least one of the plurality of user endpoints, UE via the at least one CN, in isolation of an UE traffic monitoring and determination approach.

[0047] Although examples of the concepts described herein, for example a system, donor node, CNs and UEs and methods therefor have been described in terms of an IAB and 5G communications, it is envisaged that the concepts herein described may be equally applicable to other communication systems and architectures, for example 6G.

[0048] It will be appreciated that, for clarity purposes, the above description has described example embodiments with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units or processors, for example with respect to the signal processor may be used without detracting from the example embodiments described. For example, functionality illustrated to be performed by separate processors or controllers may be performed by the same processor or controller. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[0049] Aspects may be implemented in any suitable form including hardware, software, firmware or any combination of these. The example embodiments may optionally be implemented, at least partly, as computer software running on one or more data processors and / or digital signal processors or configurable module components such as field programmable gate array (FPGA) devices. Thus, the elements and components of an embodiment may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units.Attorney Docket No. JET 2024-003 WO Specification Final

[0050] Although examples have been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined. In the claims, the term ‘comprising’ does not exclude the presence of other elements or steps.

[0051] Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. Also, the inclusion of a feature in one category of claims does not imply a limitation to this category, but rather indicates that the feature is equally applicable to other claim categories, as appropriate.

Claims

Attorney Docket No. JET 2024-003 WO Specification FinalClaims:

1. A communication system (300, 400, 600) arranged to use frequency division duplex, FDD, communications, the communication system (300, 400, 600) comprising: a centralised processing unit, CU (540); a donor node (610), operably coupled to the CU (540); a plurality of child nodes, CNs (500), where at least one child node (615) is operably coupled to the donor node (610); and plurality of user endpoints, UE (450-456, 620-625, 670-675); wherein the CU (540) is operably coupled to a CN and UE activity processing circuit (530) located in a CN (615, 665) of the plurality of CNs, wherein the CN and UE activity processing circuit (530) is configured to determine a level of traffic in the communication system that is supported by the CN (615, 665) and wherein the CU (540) is configured to instruct the CN (615, 665) to transition between an active mode of operation and an idle mode of operation in response to the determined level of traffic.

2. The communication system (300, 400, 600) of Claim 1 wherein the CU (540) is configured to alternate between a use of two frequencies in a frequency division duplex, scheme, with communications between the donor node (610) and at least one of the plurality of user endpoints, UE (450-456, 620-625, 670-675) via the at least one CN (615, 665).

3. The communication system (300, 400, 600) of Claim 2 wherein the plurality of CNs (500) are arranged to form communication layers between the at least one child node (615) and the donor node (610) and the CU (540) is configured to alternate between the use of two frequencies between successive layers in communications between the donor node (610) and at least one of the plurality of user endpoints, UE (450-456, 620-625, 670-675) via the at least one CN (615, 665).

4. The communication system (300, 400, 600) of any preceding Claim wherein the CU (540) is configured to monitor active CN activity in the network.Attorney Docket No. JET 2024-003 WO Specification Final5. The communication system (300, 400, 600) of any preceding Claim wherein the CU (540) is configured to adjust at least one transmission parameter of at least one other CN (666, 667) of the plurality of CNs (500), following the instruction to the CN (615, 665) to transition between an active mode of operation and an idle mode of operation.

6. The communication system (300, 400, 600) of Claim 5 wherein the CU (540) is configured to adjust the at least one transmission parameter of the at least one other CN (666, 667) that increases a coverage range of the at least one other CN (666, 667) following an instruction to the CN (615, 665) to transition from an active mode of operation to an idle mode of operation.

7. The communication system (300, 400, 600) of Claim 5 wherein the CU (540) is configured to adjust the at least one transmission parameter of the at least one other CN (666, 667) that decreases a coverage range of the at least one other CN (666, 667) following an instruction to the CN (615, 665) to transition from an idle mode of operation to an active mode of operation.

8. The communication system (300, 400, 600) of any preceding Claim wherein the CU (540) is configured to compare a determined level of traffic in the communication system that is supported by the CN (615, 665) to a threshold level of traffic, wherein the instruction of the CN (615, 665) to transition between an active mode of operation and an idle mode of operation is in response to the comparison of the determined level of traffic with the threshold level of traffic.

9. A base station (500, 615) arranged to communicate in a communication system (300, 400, 600) that is arranged to use frequency division duplex, FDD, communications, the communication system (300, 400, 600) comprising: at least a centralised processing unit, CU (540): a donor node (610), or at least one child node, CN, from a plurality of CNs (500); and at least one user endpoint, UE, from plurality of UEs (450-456, 620-625, 670-675); wherein the base station (500, 615) comprises:Attorney Docket No. JET 2024-003 WO Specification Final a transmitter, a receiver and a CN and UE activity processing circuit (530) configured to determine a level of traffic that is supported by the base station (500, 615) and transmit the determined level of traffic to the CU (540); and wherein the receiver is arranged to receive an instruction from the CU (540) for the base station to transition between an active mode of operation and an idle mode of operation in response to the determined level of traffic.

10. A centralised processing unit, CU (540), arranged to communicate in a communication system (300, 400, 600) arranged to use frequency division duplex, FDD, communications, the CU (540) arranged to communicate with at least one child node, CN, from a plurality of CNs (500), wherein the CU (540) is arranged to receive and process a determined level of traffic from and supported by the at least one CN, and in response thereto transmit an instruction to the at least one CN to transition between an active mode of operation and an idle mode of operation in response to the determined level of traffic.

11. A method for a communication system (300, 400, 600) that is arranged to use frequency division duplex, FDD, communications and comprises: a centralised processing unit, CU (540); a donor node (610), operably coupled to the CU (540); a plurality of child nodes, CNs (500), where at least one child node (615) is operably coupled to the donor node (610); and a plurality of user endpoints, UE (450-456, 620-625, 670-675); wherein the method comprises, at a CN (615, 665) of the plurality of CNs: determining, by a CN and UE activity processing circuit (530), a level of traffic in the communication system that is supported by the CN (615, 665) the CU (540), transmitting information that identifies the level of traffic to the CU (540); and receiving an instruction from the CU (540) to transition from an active mode of operation to an idle mode of operation in response to the determined level of traffic.

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