Systems and methods for resource allocation chain construction and advance planning time calculation in cell-free networks

Abstract

Systems and methods for medium access control (MAC) scheduling in cell-free networks are discussed. In some cases, a layer 3 (L3) scheduler of a cluster of base stations serving a user equipment (UE) identifies a first set of responsible base stations for a set of MAC entities from the cluster of base stations, constructing a set of resource allocation chains for the base stations of the cluster, calculates a set of advance planning times for the set of MAC entities based on the set of resource allocation chains, and provides the first set of advance planning times for the set of MAC entities to the first set of responsible base stations. Mechanisms of the responsible base stations for making and communicating resource allocation decisions using the set of resource allocation chains are also discussed. Fairness mechanisms for such decisions are also discussed.

Description

SYSTEMS AND METHODS FOR RESOURCE ALLOCATION CHAIN CONSTRUCTION AND ADVANCE PLANNING TIME CALCULATION IN CELL- FREE NETWORKS TECHNICAL FIELD

[0001] This application relates generally to wireless communication systems, including medium access control (MAC) scheduling in cell-free networks. BACKGROUND

[0002] Wireless mobile communication technology uses various standards and protocols to transmit data between a base station (BS) and a wireless communication device. Wireless communication system standards and protocols can include, for example, 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) (e.g., 4G), 3GPP New Radio (NR) (e.g., 5G), and Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard for Wireless Local Area Networks (WLAN) (commonly known to industry groups as Wi-Fi®).

[0003] As contemplated by the 3GPP, different wireless communication systems' standards and protocols can use various radio access networks (RANs) for communicating between a base station of the RAN (which may also sometimes be referred to generally as a RAN node, a network node, or simply a node) and a wireless communication device known as a user equipment (UE). 3GPP RANs can include, for example, Global System for Mobile communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and / or Next-Generation Radio Access Network (NG-RAN).

[0004] Each RAN may use one or more radio access technologies (RATs) to perform communication between the base station and the UE. For example, the GERAN implements GSM and / or EDGE RAT, the UTRAN implements Universal Mobile Telecommunication System (UMTS) RAT or other 3GPP RAT, the E-UTRAN implements LTE RAT (sometimes simply referred to as LTE), and NG-RAN implements NR RAT (sometimes referred to herein as 5G RAT, 5G NR RAT, or simply NR). In certain deployments, the E-UTRAN may also implement NR RAT. In certain deployments, NG-RAN may also implement LTE RAT.1 4894-4182-1929\1

[0005] A base station used by a RAN may correspond to that RAN. One example of an E-UTRAN base station is an Evolved Universal Terrestrial Radio Access Network (E- UTRAN) Node B (also commonly denoted as evolved Node B, enhanced Node B, eNodeB, or eNB). One example of an NG-RAN base station is a next generation Node B (also sometimes referred to as a g Node B or gNB).

[0006] A RAN provides its communication services with external entities through its connection to a core network (CN). For example, E-UTRAN may utilize an Evolved Packet Core (EPC) while NG-RAN may utilize a 5G Core Network (5GC). BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0007] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0008] FIG. 1 illustrates a diagram for an example of clustering in a cell-free network architecture.

[0009] FIG. 2 illustrates a diagram showing aspects of radio protocol use in cell-free network mechanisms.

[0010] FIG. 3 illustrates a diagram showing a cluster of base stations and MAC entity options for that cluster, according to embodiments discussed herein.

[0011] FIG. 4 illustrates diagram of a network-level view of a wireless communication system that shows the relation of various MAC entities used in the wireless communication system and relation to various base stations.

[0012] FIG. 5 illustrates a diagram showing a portion of a protocol stack and its visualized application within a cluster, corresponding to a case of MAC configuration as discussed herein.

[0013] FIG. 6 illustrates a diagram for a MAC entity M1that may be scheduled by a MAC scheduler of a cluster.

[0014] FIG. 7 illustrates an example network topology for which one or more resource allocation chains may be established.

[0015] FIG. 8 illustrates a diagram for an example of time planning for a resource allocation chain, according to embodiments discussed herein.2 4894-4182-1929\1

[0016] FIG. 9 illustrates a diagram for an example of time planning for a MAC entity, according to embodiments discussed herein.

[0017] FIG. 10 illustrates a diagram corresponding to the construction of a feasible solution, according to embodiments discussed herein.

[0018] FIG. 11 illustrates a flow diagram for communications between a CCF and an L3 scheduler corresponding to a first option for MAC entity addition, according to embodiments discussed herein.

[0019] FIG. 12 illustrates a flow diagram for communications between a CCF and an L3 scheduler corresponding to a second option for MAC entity addition, according to embodiments discussed herein.

[0020] FIG. 13 illustrates a flow diagram for communications between a CCF and an L3 scheduler corresponding to an option for MAC entity removal, according to embodiments discussed herein.

[0021] FIG. 14 illustrates a flow diagram for communications between a CCF and an L3 scheduler corresponding to an L3 procedure for reconfiguring resource allocation chains, according to embodiments discussed herein.

[0022] FIG. 15A illustrates a diagram illustrating the input of previous resource allocation decisions for one or more MAC entities to a base station b from a set of Prec(b) base stations and a subsequent output of resource allocation decisions for one or more MAC entities from the base station b to a set of Succ(b) base stations.

[0023] FIG. 15B illustrates a flow diagram showing details of the communications between the base station b, the set of Prec(b) base stations, and the set of Succ(b) base stations corresponding to FIG. 15A.

[0024] FIG. 16A illustrates a network-level view of a wireless communication system that shows the relation of various MAC entities used by the wireless communication system and their relation to various base stations.

[0025] FIG. 16B illustrates first example of resource distribution corresponding to the wireless communication system of FIG. 16A in the case where there is no use of a virtual MAC fairness mechanism.

[0026] FIG. 16C illustrates second example of resource distribution corresponding to the wireless communication system of FIG. 16A in the case where there is a use of a virtual MAC fairness mechanism.3 4894-4182-1929\1

[0027] FIG. 17 illustrates a method of a L3 scheduler of a cluster of base stations serving a UE, according to embodiments discussed herein.

[0028] FIG. 18 illustrates a method of a first responsible base station that is responsible for a first MAC entity comprising a first plurality of base stations within a cluster of base station serving a UE, according to embodiments discussed herein.

[0029] FIG. 19 illustrates an example architecture of a wireless communication system, according to embodiments disclosed herein.

[0030] FIG. 20 illustrates a system for performing signaling between a wireless device and a network device as supported by a CN device, according to embodiments disclosed herein. DETAILED DESCRIPTION

[0031] Various embodiments are described with regard to a UE. However, reference to a UE is merely provided for illustrative purposes. The example embodiments may be utilized with any electronic component that may establish a connection to a network and is configured with the hardware, software, and / or firmware to exchange information and data with the network. Therefore, the UE as described herein is used to represent any appropriate electronic component. Embodiments for Cell-Free Procedures Timescales

[0032] In non-real time (e.g., a matter of seconds) cell-free procedures, inputs may include, for example, an inter-base station exchange (Xn) latency, radio bearers configuration, and / or UE capabilities. Decisions made during non-real time cell-free procedures may include: clusters with relevant base station identifications, sub-cluster structures with sub-clusters for each Radio Bearer and the establishment of radio link control (RLC) entities, and / or medium access control (MAC) entities establishment with base station and RLC identification. The responsible control entity for non-real time cell- free procedures may be a cluster control function.

[0033] In near-real time (e.g., a matter of dozens to hundreds of milliseconds) cell-free procedures, inputs may include, for example, a propagation delay from the UE to the base stations, a base station state (load, signal quality), and / or traffic statistics. Decisions during near-real time cell-free procedures may include:4 4894-4182-1929\1• Physical layer (PHY) restrictions with propagation delay and synchronization impairments; • MAC layer transport block (TB) number configuration or scheduling pattern agreement; • MAC scheduler decisions for the selection of a responsible base stations and resource allocation chains; • RLC-MAC link activation; and / or • Packet data convergence protocol (PDCP)-RLC link traffic routing and duplication.

[0034] The responsible control entity for near-real time cell-free procedures may be a Layer 3 (L3) scheduler.

[0035] In real time (e.g., as soon as possible, or as a matter of milliseconds or less than milliseconds) cell-free procedures, inputs may include, for example, CSI, buffer statuses, and / or scheduling metrics. Decisions during real time cell-free procedures may include: • MAC scheduler decisions for coordination message exchange, radio resource allocation, and / or link adaptation; • MAC layer Layer 2 (L2) data processing; and / or • PHY multi user multiple input multiple output (MIMO) (MU-MIMO) precoding, Layer 1 (L1) data transmission / reception.

[0036] The responsible control entity for real time cell-free procedures may be a MAC scheduler. Embodiments for Clustering in Cell-Free Networks

[0037] In some wireless communication systems, a cell-free network architecture provides an adaptive / dynamic and UE-centric distribution of functionalities that may be associated with a “serving cell” as understood in the context of prior cell-based network architectures (e.g., such as an NR network architecture or an LTE network architecture). With respect to the present disclosure, it may be understood generally that a “cluster” or “serving cluster” of a UE is a set of physically and / or logically connected base stations over which functionalities related to the serving the UE (e.g., traditional serving cell functionalities used in cell-based network architectures) may be distributed. Accordingly, (the concept of) a cluster may, under some perspectives, “replace” (the concept of) a serving cell of a UE as understood for prior cell-based networks.5 4894-4182-1929\1

[0038] A cluster may have a one-to-one mapping with a UE. Thus, separate (logical) clusters for each of two UEs may be understood / cognizable (even when each of the two corresponding clusters is made up of the same physical set of base stations). Further, note that a single base station may simultaneously belong to multiple clusters that each serve different UEs.

[0039] FIG. 1 illustrates a diagram 100 of an example of clustering in a cell-free network architecture. A first cluster 102 of base stations serves a first UE 104 and a second cluster 106 of base stations serves the second UE 108. As illustrated, the first cluster 102 includes the first base stations 110 and the second base stations 112, while the second cluster 106 includes the second base stations 112 and the third base station 114.

[0040] Base stations in a same cluster are not necessarily required to jointly transmit / receive to / from the UE being served. Further, control plane and / or user plane functionalities may be dynamically distributed among the base stations in the cluster.

[0041] A clustering control function (CCF) may be defined as one or more logical function sets for the establishment and control of clusters in the wireless communication system. The CCF may be a distributed entity of the wireless communication system. For example, the CCF may be distributed across one or more of the core network, a RAN intelligent controller (RIC), and / or one or more base station(s) of the RAN.

[0042] The CCF may dynamically develop, update, control, and schedule UE-centric connected sets of clusters in certain geographical areas based on, for example: traffic, latency, reliability, coverage, interference, sensing, mobility, cell load, radio resource management (RRM) aspects, radio link quality, backhaul ideality, location, quality of service (QoS) requirements, and / or measurement reports, etc.

[0043] In some wireless communication systems, clustering in cell-free networks includes concepts such as a UE-centric cluster, a CCF, connected base stations (cBSs) (e.g., base stations that are part of a cluster serving a UE), neighboring un-connected base stations (uBSs) (e.g., neighboring base stations to a UE that are not currently part of a cluster serving the UE), etc. In some such systems, a CCF includes functionalities, protocols, message exchange capabilities, and the like that may be used for cluster establishment and / or update tasks (among other things). UEs and base stations may include corresponding functionalities, protocols, message exchange capabilities, and the like supporting the use of clustering as described herein.6 4894-4182-1929\1

[0044] In wireless communication systems implementing cell-free networks, it may be that cell-free radio resource control (RRC) connection establishment and maintenance messaging protocols are used. This may mean, among other things, that an RRC state of a UE is understood with respect to the network generally (rather than with respect to a particular serving cell).

[0045] Further, such wireless communication systems for cell-free networks may use one or more cluster establishment options corresponding to an initial access of the UE and / or to cluster updating mechanisms (e.g., that control the composition of base stations in the cluster after the UE's initial access). These may include, for example, “greedy”, downlink (DL)-based, uplink (UL)-based, and / or real-time methodologies (and any corresponding message exchanges). Embodiments Radio Protocol Aspects in Cell-Free Networks

[0046] In some wireless communication systems, “cluster partitioning” represents a radio-bearer-specific dynamic partition of a cluster serving a UE into logical sub- clusters. Such a cluster partitioning into sub-clusters may be determinative of a protocol stack architecture that applies with respect to that cluster. For example, sub-clusters according to the partitioning may be in one-to-one correspondence with RLC entities. Base stations in a same sub-cluster may then, for example, each carry a copy of the same logical RLC entity for a given radio bearer.

[0047] FIG. 2 illustrates a diagram 200 showing aspects of radio protocol use in cell- free network mechanisms. A UE 202 is served by a cluster 204. Within the cluster 204, there is a first sub-cluster 206 that corresponds to a first RLC entity 210 used between the UE 202 and the cluster 204 and a second sub-cluster 208 that corresponds to a second RLC entity 212 between the UE 202 and the cluster 204. The first RLC entity 210 and the second RLC entity 212 are RLC entities used by a PDCP entity 218 that corresponds to a radio bearer between the UE 202 and the cluster 204 and that uses the illustrated cluster partitioning.

[0048] As illustrated, the first RLC entity 210 is synchronized 214 across the base stations of the first sub-cluster 206 (BS1, BS2, and BS3). This means that, for example, each of these base stations has and operates according to a copy of the first RLC entity 210, as shown. Further, the second RLC entity 212 is synchronized 216 across the base stations of the second sub-cluster 208 (BS4, BS5, and BS6). This means that, for7 4894-4182-1929\1example, each of these base stations has and operates according to a copy of the second RLC entity 212, as shown. Note that, as illustrated, the arrangement of particular base stations of the cluster into the first sub-cluster 206 or second sub-cluster 208 may be transparent to the UE (the UE knows about / operates in terms of the first RLC entity 210 and the second RLC entity 212 (in terms of the sub-clusters), without consideration with respect to particular base stations underlying those RLC entities / sub-clusters).

[0049] In the illustrated case, a first packet 220 of the radio bearer corresponding to the PDCP entity 218 is handled at the first RLC entity 210. This ultimately means that the first packet 220 is communicated between the UE 202 and the cluster 204 via one or more of the base stations of the first sub-cluster 206. Further, a second packet 222 of the (same) radio bearer corresponding to the PDCP entity 218 is handled at the second RLC entity 212. This ultimately means that the second packet 222 is communicated between the UE 202 and the cluster 204 via one or more of the base stations of the second sub- cluster 208.

[0050] It is contemplated that a cluster partitioning may be updated over time. Establishment and / or updating of a cluster partitioning may take into account QoS requirements and traffic properties associated with a radio bearer. For example, latency constraints, and / or traffic periodicity may be considered. These mechanisms allow the network (e.g., a CCF) to optimally configure sub-cluster-enabled multi-connectivity of a UE to a cluster in, for example, a non-ideal backhaul scenario (where different partitionings of a same cluster may have appreciably different QoS / traffic management characteristics).

[0051] In some wireless communication systems, radio protocols in cell-free networks utilize concepts such as cluster partitioning / sub-clusters, RLC synchronization, etc. A functionality for control over dynamically updating cluster partitions, and a corresponding protocol for the update procedure, may be used. PDCP data routing options and a corresponding configuration may be used. Finally, a cell-free radio bearer configuration and / or a message exchange procedure for radio bearer establishment may be used. Embodiments of MAC Entity Establishment

[0052] FIG. 3 illustrates a diagram 300 showing a cluster 302 of base stations and MAC entity options 312 for that cluster, according to embodiments discussed herein. The8 4894-4182-1929\1cluster 302 serves the UE 310 using the first base station 304 (BS1), the second base station 306 (BS2) and the third base station 308 (BS3).

[0053] With respect to the cluster 302, the following MAC entity options 312 exist. A first MAC entity option may be for a first MAC entity 314 that uses the first base station 304. A second MAC entity option may be for a second MAC entity 316 that uses the second base station 306. A third MAC entity option may be for a third MAC entity 318 that uses the third base station 308. A fourth MAC entity option may be for a fourth MAC entity 320 that uses the first base station 304 and the second base station 306. A fifth MAC entity option may be for a fifth MAC entity 322 that uses the first base station 304 and the third base station 308. A sixth MAC entity option may be for a sixth MAC entity 324 that uses the second base station 306 and the third base station 308. A seventh MAC entity option may be for a seventh MAC entity 326 that uses the first base station 304, the second base station 306, and the third base station 308.

[0054] With respect to designs for MAC entities, it may be that each MAC entity created with respect to / for a UE is associated with a unique set of base stations of the cluster serving that UE. It may be that an MAC entity can be connected to (can potentially serve) an RLC entity if the delays provided by a Xn latency of inter-base- station communication within the MAC entity and by MAC scheduling coordination are acceptable for that RLC entity. It may be that such a connection between an RLC entity and a MAC entity can be activated and / or deactivated (such that the MAC entity begins actively serving / stops actively serving the RLC entity) at a near-real time timescale.

[0055] Note that a timescale of decision making for MAC entity creation is generally longer than the timescale for RLC entity to MAC entity connection activation / deactivation. For example, MAC entity creation is typically a non-real time process, where the set of created MAC entities may be updated on the order of, e.g., seconds. However, the activation of a MAC entity to RLC entity connection may be a near-real time process (a faster process) that may occur on the order of dozens or hundreds of milliseconds. Embodiments of Multiple MAC Entities in Cell-Free Networks

[0056] In some wireless communication systems, a MAC entity is associated with a UE and a subset of base stations. Further, in some cases, the UE might have more than one MAC entity. B is provided as a set of base stations in the system and is provided as a9 4894-4182-1929\1set of MAC entities in the system. A MAC entity may map data onto the radio resources of all base stations that are associated with it. The radio resources of each base station may be allocated among the MAC entities to which the base station is associated.

[0057] FIG. 4 illustrates diagram 400 of a network-level view of a wireless communication system 402 that shows the relation of various MAC entities used in the wireless communication system 402 and their relation to various base stations. As illustrated, the various MAC entities use various ones of the base stations (and note that there are multiple multi-BS MAC entities and one single-BS MAC entity). For example, as can be seen from the wireless communication system 402 (and as represented in the first listing 404), the MAC entity M1406 includes the base station b0420, the base station b2424, and the base station b3426; the MAC entity M2408 includes the base station b3426 and the base station b4428; the MAC entity M3410 includes the base station b0420, the base station b4428, and the base station b5430; the MAC entity M4412 includes the base station b0420 and the base station b6432; the MAC entity M5414 includes the base station b6432 and the base station b7434; the MAC entity M6416 includes the base station b0420; and the MAC entity M7418 includes the base station b0 420, the base station b1422, the base station b2424, the base station b3426, the base station b4428, the base station b5430, the base station b6432, and the base station b7 434.

[0058] A MAC scheduler may be provided as a module in / for the wireless communication system 402. The MAC scheduler may be responsible for radio resource allocation and selection of transmission parameters (e.g., modulation and coding scheme (MCS), rank, precoding option, etc.) for such transmissions. Further, a MAC scheduler in cell-free network may be a network-level algorithm that works across the base stations of the wireless communication system 402. Embodiments for Cell-Free, UE-Centric MAC Entity Configuration

[0059] FIG. 5 illustrates a diagram 500 showing a portion of a protocol stack 502 and its visualized application within a cluster 504, corresponding to a case of MAC configuration as discussed herein. As illustrated, the cluster 504 uses the first base station 506 (BS1), the second base station 508 (BS2), and the third base station 510 (BS3) to serve the UE 512.10 4894-4182-1929\1

[0060] The diagram 500 illustrates a PDCP entity 514 corresponding to a radio bearer that is served by a first RLC entity 516 representing a first sub-cluster that includes the first base station 506 (BS1) and the second base station 508 (BS2), and a second RLC entity 518 representing a second sub-cluster that includes the third base station 510 (BS3), in the manner discussed herein.

[0061] The diagram 500 further illustrates that first RLC entity 516 is itself served by a first MAC entity 520 that can perform MAC scheduling using the first base station 506 and the second base station 508 and that the second RLC entity 518 is served by a second MAC entity 522 that can perform MAC scheduling using the third base station 510.

[0062] By way of example, in FIG. 5 it is the case that the first MAC entity 520 is co- extensive with the first RLC entity 516 with respect to included base stations and that the second MAC entity 522 is co-extensive with the second RLC entity 518 with respect to included base stations. This is given by way of example and not by way of limitation. For example, while in this case the first MAC entity 520 covers all base stations of the sub-cluster of the first RLC entity 516, this should be understood by way of example only (it is possible that a MAC entity covers fewer than all base stations of an RLC entity / sub-cluster that it serves).

[0063] In some wireless communication systems, resource allocation decisions for a MAC entity having multiple base stations (e.g., the first MAC entity 520, as illustrated) are made jointly by the base stations within that MAC entity. As an example, for the first MAC entity 520, a resource allocation decision may be made by the first base station 506 and provided to the second base station 508 via an Xn interface. Due to Xn latency, the resource allocation decision may be made for a transmission time interval (TTI) in the future (by at least an applicable Xn latency time). This is understood to add Xn latency to the overall scheduling latency. Joint resource allocation as so used accordingly may be understood to provide high spectral efficiency but to introduce / add latency. This joint scheduling accordingly may be a rational choice in the context of allocations for latency- tolerant traffic.

[0064] In some wireless communication systems, resource allocation decisions across multiple MAC entities used by a UE (e.g., across the first MAC entity 520 and the second MAC entity 522 used by the UE 512) may be made in a decentralized manner by base stations of the different MAC entities used by the UE. First, those base stations may11 4894-4182-1929\1agree about a coordinated allocation pattern (in time, frequency and / or spatial domains) that applies over a period of time. As an example, the base stations can agree to allow the first MAC entity 520 be scheduled at even TTIs and to further allow the second MAC entity 522 be scheduled at odd TTIs. Other possible examples can include having the base stations agree on a coordination in a frequency band and / or in a spatial domain (for multi-antenna UEs). In real-time, each base station may decide to schedule a MAC entity in compliance with the coordinated allocation pattern. Decentralized scheduling as so used accordingly may be understood not add latency, but might achieve less spectral efficiency as compared with a joint decision option across MAC entities. Embodiments for Single-Base-Station and Cross-Base-Station MAC Schedulers

[0065] The availability of a single-base-station scheduling algorithm that can allocate radio bearers (RBs) and select transmission parameters for the served UEs (MAC entities) may be assumed. However, more particular aspects of the scheduler (such as the scheduler being of a particular type) may not be assumed – instead, for these aspects the MAC scheduler may be conceived as a “black-box” / as implementing a “black box” algorithm.

[0066] An enhancement to such a single-base-station scheduling algorithm to make it useable as a multiple-base-station scheduling algorithm is contemplated. Such an enhancement may provide for a resource allocation for jointly scheduled base stations and that is jointly optimized for UEs served by those base stations. In some cases for such enhancement, for each UE, PHY measurements and link quality estimation of the jointly scheduled base stations are available. In some cases for such enhancement, joint multiple input multiple output (MIMO) precoding and reception are considered if they are supported by PHY.

[0067] FIG. 6 illustrates a diagram 600 for a MAC entity M1602 that may be scheduled by a MAC scheduler 604 of a cluster. As illustrated, the MAC entity M1602 includes the base station b0606, the base station b1608, and the base station b2610.

[0068] The MAC scheduler 604 may schedule the MAC entity M1602 according to various inputs, including buffer status / service histories 612 for the UE(s) using the MAC entity M1602, the PHY measurements / link quality estimations 614 for the UE(s) using the MAC entity M1602, and / or link adaptation / QoS parameters 616 for the UE(s) using the MAC entity M1602. The outputs of the MAC scheduler 604 may include resource12 4894-4182-1929\1allocation 618 for the UE(s) (e.g., time and frequency domain resource allocation) and / or transmission parameters 620 (e.g., modulation and coding scheme (MCS), rank, precoding, etc.).

[0069] Such enhancement may provide a solution for scheduling problems in a specific situation where the MAC entities of all the UEs either coincide as subsets of base stations, or where such MAC entities do not intersect. However, it is noted that the existence of these conditions would be atypical with respect to the use of many of the user-centric cell-free networks as conceived and described herein. More typically, MAC entities (as conceived as subsets of base station(s), as discussed herein) of a cluster will overlap heavily with each other. Refer to, e.g., the wireless communication system 402 of FIG. 4. Embodiments for Generalized MAC Scheduling in Cell-Free Networks

[0070] Accordingly, embodiments herein discuss systems and methods for performing resource allocation as between multiple MAC entities (each having one or more base stations) in cases where base station sets of the MAC entities may overlap (e.g., including for cases with a high level of such overlap). Such cases are expected to be typically seen in implementations of cell-free, user-centric networks as discussed herein.

[0071] The resource allocation algorithms as proposed with respect to embodiments discussed herein accordingly resolve the problem of generalization to such overlapping base station set cases. It is desirable that a such a resource allocation solution be scalable (e.g., operates\ with any size of the network), minimize the introduced coordination delays, work to make coordination delays for any single-base-stations MAC entities negligible, and / or maximize communication efficiency (e.g., spectral efficiency) while preserving fairness throughout the system. Embodiments discussed herein for generalized solutions for resource allocation in cell-free user-centric approaches in MIMO networks are built upon these characteristics.

[0072] Embodiments discussed herein provide for various protocol enhancements. Various embodiments discussed herein provide for concepts of resource allocation chains of base stations and of a responsible base station of a MAC entity. Various embodiments discussed herein provide for functionalities of a Layer 3 (L3) scheduler to construct and update the resource allocation chains. Various embodiments discussed herein define interactions between an L3-scheduler and a CCF that allow for13 4894-4182-1929\1functionalities described herein. Various embodiments discussed herein provide for real- time cross-BS input and / or output messages for resource allocation decisions. Various embodiments discussed herein relate to configurations of a real-time radio resource scheduler. Various embodiments discussed herein relate to concepts of virtual MACs and related methods to establish fairness throughout the system. Embodiments of L3 Procedures for Resource Allocation Chain Management

[0073] FIG. 7 illustrates an example network topology 700 for which one or more resource allocation chains may be established. As illustrated, the set of base stations B within the network topology 700 includes the base station b0702, the base station b1704, and the base station b2706.

[0074] In some embodiments, for each base station b, a resource allocation chain of the radio resources of b is defined as a finite sequence of base stations: Ch(b) ≔ (Ch0(b), Ch1(b), …, Chn(b)(b)), where: • Chk(b) ∈ B is k-th element of the base station b-th chain; • n(b) ∈ ℕ is the number of elements minus one in base station b-th chain; • Ch0(b) = b; which denotes that the chain starts with the base station for which it is constructed, and • Chi(b) ≠ Chj(b), ∀ i ≠ j, which denotes that base stations within a single chain are all different.

[0075] In the algorithm, a single resource allocation chain is constructed for each base station, thus Chk(b) ∈ B will be defined for each k = 1, …, n(b). The purpose of the resource allocation chain construction is to define which base stations (and in which order) will allocate the radio resources of the base station b. Base station Chn(b)(b) starts the resource allocation of BS b, allocates some resources, then passes the result to base station Chn(b)−1(b). Accordingly, it is understood that a base station Chk(b) that is not Chn(b)(b) may receive a partial allocation result for base station b from base station Chk+1(b). This base station Chk(b) then proceeds to allocate some of the remaining available resources without touching any already made resource allocation(s).

[0076] With respect to the reference to the network topology 700 presented in FIG. 7, where B = {b0, b1, b2}, one example set of such resource allocation chains (among various possibilities) is: • Ch(b0) = (b0, b1, b2), where n(b0) = 2;14 4894-4182-1929\1• Ch(b1) = (b1), where n(b1) = 0; and • Ch(b2) = (b2, b0), where n(b2) = 1.

[0077] Note that herein, when providing discussion related a resource allocation chain Ch(b), the base station b may be referred to as “the base station that is described by the resource allocation chain Ch(b).” Embodiments for Time Planning for Resource Allocation Chains

[0078] In some embodiments, a scheduling algorithm at each base station can be performed within a time δ. Further, a latency of Xn communication between base stations is known for the network. The latency of base station bito base station bjcommunication may be denoted as follows: l(bi, bj) ∈ . Note that in some examples herein, the notation l(bi, bj) may be further reduced / shorthanded to the equivalent notation li,j.

[0079] Within this framework, a decision propagation time along the chain of b may be defined as follows: , where:station Chk(b) can be for a TTI that is not closer to a current TTI (the TTI at the time that Chk(b) makes the resource allocation) than by .time planning for a resource allocation chain, according to embodiments discussed herein. The diagram 800 illustrates a network topology that includes the base station b0802, the base station b1804, and the base station b2806.

[0082] Further, the diagram 800 illustrates details of a resource allocation “path” for a resource allocation chain 812 Ch(b0) = (b0, b1, b2) for the base station b0802 (and note that n(b0) = 2). More specifically, the diagram 800 illustrates, according to the notation Ch(b0) = (b0, b1, b2) for the resource allocation chain 812, that:15 4894-4182-1929\1• First, the base station b2806 allocates resources of the base station b0802. This allocation takes an amount of time of (less than or equal to) δ. • Second, the result of the resource allocation decision taken at the base station b2806 is communicated to the base station b1804 (which is the next base station on the resource allocation chain). The time taken for this communication corresponds to a first latency 808 of an Xn interface between the base station b2806 and the base station b1804, which is represented in the diagram 800 as l(b1, b2). • Third, the base station b1804 allocates (heretofore unallocated) resources of the base station b0802. This allocation takes an amount of time of (less than or equal to) δ. • Fourth, the result of the resource allocation decisions taken at each of the base station b2806 and the base station b1804 are communicated to the base station b1804 (which is the next base station on the resource allocation chain). The time taken for this communication corresponds to a second latency 810 of an Xn interface between the base station b1804 and the base station b0802, which is represented in the diagram 800 as l(b0, b1). • Fifth, the base station b0802 allocates (heretofore unallocated) resources of the base station b0802. This allocation takes an amount of time of (less than or equal to) δ.

[0083] Note that the amounts of time referenced in the preceding five steps correspond to the calculation of L(0, 2, b0) (using the formula presented above) as illustrated in the diagram 800. The ultimate result is that, as illustrated, the minimum amount of time back from a target TTI for the to-be-allocated resources at the base station b0802 according to which the base station b2806 at the beginning of the resource allocation chain must start the described process is equal to the sum of the first latency 808 of the Xn interface between the base station b2806 and the base station b1804 (l(b1, b2)), the second latency 810 of the Xn interface between the base station b1804 and the base station b0802, (l(b0, b1)), and the individual times for processing / generating resource allocation decisions at each of the three base stations in the resource allocation chain (3 ⋅ δ). Embodiments for Responsible Base Stations and Time Planning

[0084] In some embodiments, for each MAC entity , where M is associated to a subset of base stations, a responsible base station may be defined. This16 4894-4182-1929\1responsible base station, denoted as , is responsible for the radio resource allocation for MAC entity M. The radio resources in question are radio resources across all base stations in the MAC entity M. To simplify the implementation, a responsible base station of a MAC is to be understood to be associated with that MAC entity (i.e., ).

[0085] The notion of an advance planning time for a MAC entity is now introduced. This advance planning time is a (minimum) time distance between a moment of a resource allocation decision and closest possible allocated resource in time domain. Correspondingly, if a MAC entity is allocated by a base station Chk(b), it cannot allocated / be provided with resources that are closer than L(k, b) in the time domain to a current TTI.

[0086] A chain index function may be defined as follows: .MAC can be defined as: given the construction of resource base stations.

[0088] FIG. 9 illustrates a diagram 902 for an example of time planning for a MAC entity, according to embodiments discussed herein. The diagram 902 illustrates a network topology that includes the base station b0904, the base station b2906, the base station b3908, the base station b4910, the base station b5912, and the base station b6 914. As illustrated, the base station b0904, the base station b2906, and the base station b3908 are included in a MAC entity M1916 (while the base station b4910, the base station b5912, and the base station b6914 are not included in the MAC entity M1916).

[0089] As illustrated, the base station b0904 acts as the responsible base station for the MAC entity M1916. Accordingly, the advance planning time applicable to the MAC entity M1916 is the longest decision propagation time L(0, k1, b) as calculated at each of the resource allocation chains for each base station b in the MAC entity, where k1 in each case is the index for the location of the responsible base station within that resource allocation chain.17 4894-4182-1929\1

[0090] In the illustrated example, for the MAC entity M1916, the applicable decision propagation times L(0, k1, b) are calculated using each of a first resource allocation chain 918 of the base station b0904, a second resource allocation chain 920 for the base station b2906, and a third resource allocation chain 922 for a base station b3908, where k1in each case is set to the indexed location of the base station b0904 within the applicable resource allocation chain.

[0091] According to this formulation, the applicable decision propagation time for the base station b0904 is L(0, 0, b0). Further, the applicable decision propagation time for the base station b2906 is L(0, 2, b2). Still further, the applicable decision propagation time for the base station b3908 is L(0, 2, b3). So, the (overall) advance planning time applicable to the MAC entity M1916 is the longest (in time) of L(0, 0, b0), L(0, 2, b2), and L(0, 2, b3), as illustrated. Embodiments Corresponding to Feasibility and Optimality

[0092] In some embodiments, an algorithm for cell-free MAC entity scheduling may: • Construct a resource allocation chain for each ; and • Assign a responsible base station for each MAC entity M (where , ), such that the following feasibility condition is satisfied:.

[0093] A pair of (Ch, Rsp) (a construction of a set of resource allocation chains for the base stations of the system and a set of responsible base station assignments for one or more base stations in the system) is called feasible if the feasibility condition is satisfied for all MAC entities in the system. Note that according to embodiments herein, it is always possible to find at least one feasible pair of .

[0094] Given the , , , and latencies , the advance planning time is uniquely defined for eachThe system may be configured to achieve lower values for . The corresponding optimization problem could be defined as follows: • , where the minimum is taken over all18 4894-4182-1929\1• , M. solutionfor 1. each MAC , select one of the base stations to be the base station. 2. For each base, provide a list of all MAC entities that have b in their base station set: .3. For each base station , create a list of all base stations that are responsible for one or more MAC entities in , excluding b itself, as follows: . 4. Order elements of (e.g., by base station identifiers (IDs)), and identify the ordered results with the part of the resource allocation chain as follows: . 5. b at the start of thechain: .

[0096] It is noted that by performing construction in this manner, the feasibility condition of is satisfied.

[0097] Optimization opportunities (flexibilities) with respect to the above procedure include, for example, making optimized selections of according to part 1 above and performing optimized ordering of the according to part 4 above.

[0098] FIG. 10 illustrates a diagram 1000 corresponding to the construction of a feasible solution, according to embodiments discussed herein. The diagram 1000 re-uses the wireless communication system 402 as discussed in FIG. 4, including using the same makeup of MAC entities and base stations as represented by the first listing 404 as is described in the discussion of FIG. 4.

[0099] Assuming the wireless communication system 402 as defined according to the first listing 404, a second listing 1002 representing selections of responsible base stations Rsp(M) for each MAC entity M that can be generated according to part 1 above.19 4894-4182-1929\1

[0100] Further, again assuming the wireless communication system 402 as defined according to the first listing 404, a third listing 1004 representing MAC entities in which each base station is included can be generated according to part 2 above.

[0101] The fourth listing 1006 representing the resource allocation chains Ch(b) for each of the base stations b can then be generated according to part 3, part 4, and part 5 above. This solution is feasible with respect to the MAC entity arrangement of the wireless communication system 402.

[0102] Note that the diagram 1000 also includes a fifth listing 1008 for advance planning times for each MAC entity M that are calculable using the resource allocation chains of the fourth listing 1006 according to the responsible base station assignments of the second listing 1002 (times Time(M | Ch, Rsp) – refer to, e.g., section “Embodiments for Responsible Base Stations and Time Planning” described elsewhere herein). Embodiments for L3 Procedures

[0103] In some embodiments, from the perspective of the overall cell-free architecture, the selection of / construction of a solution of (Ch, Rsp) is considered to be a near real- time procedure, and thus may fall under control of / can be considered as a functionality of an L3 scheduler. It is contemplated that an L3 scheduler may be understood as a RAN function. For example, an L3 scheduler may be implemented across RAN nodes (e.g., BSs, control unit(s) (CU(s)) and / or distributed unit(s) DU(s)), by a RAN cloud entity, and / or by a dedicated controlling entity (e.g., a RAN intelligent controller (RIC)).

[0104] Further behaviors for the L3 scheduler related to the active solution of (Ch, Rsp) may be considered. These further behaviors may include behaviors for the maintenance of (e.g., an already constructed) set of resource allocation chains. These further behaviors may also / alternatively include behaviors for the (re)selection of responsible base stations.

[0105] L3 behaviors corresponding to instances of MAC entity addition and / or removal are now discussed. First, recall that a CCF in a cell-free system may be responsible for creation and removal of L2 entities. Thus, the CCF may decide to add a MAC entity to the system or to eliminate an existing MAC entity from the system.

[0106] Corresponding to cases for adding an unrepresented / unused MAC entity to the cell-free system, it is noted that it is always possible to incorporate the MAC entity into an existing L3 scheme for (Ch, Rsp) such that advance planning time of any already20 4894-4182-1929\1existing MAC entities is not increased. For example, after a MAC entity is created, can change to include this MAC for some base stations b. Thus, the sets alsomight more base stations. If these new base stations are added to the ends of the exiting chains,, the advance planning time for already existing will

[0107] It will further be understood the system does not increase the advance planning time of any remaining MAC entity.

[0108] For cases of L3 chain re-configuration (which may occur periodically and / or based on triggering events), the L3 scheduler may run an optimization procedure that includes reselecting the responsible base stations and / or reconstructing the resource allocation chains (generating a new (Ch, Rsp) solution) with the goal of modifying (e.g., further minimizing) one or more latency characteristic(s) of the distributed resource allocation scheme.

[0109] FIG. 11 illustrates a flow diagram 1100 for communications between a CCF 1102 and an L3 scheduler 1104 corresponding to a first option for MAC entity addition, according to embodiments discussed herein.

[0110] First, the CCF 1102 creates 1106 a new MAC entity (Mnew). Context information for the new MAC entity may include the constituent base station(s) of the new MAC entity. The CCF 1102 sends 1108 this context information to the L3 scheduler 1104.

[0111] Based on the received context information for the new MAC entity, the L3 scheduler 1104 selects 1110 a responsible base station for the new MAC entity that is one of the base station(s) of the new MAC entity.

[0112] The L3 scheduler 1104 then checks 1112 the resource allocation chain for each of the base station(s) that are in the new MAC entity. For each of these resource allocation chains that does not include the selected responsible base station, the selected responsible base station is added to the end of that chain.

[0113] Then the L3 scheduler 1104 calculates 1114 an advance planning time for the new MAC entity based on the resource allocation chain(s) for the base station(s) in the new MAC entity (e.g., as is described elsewhere herein).

[0114] In some embodiments, the L3 scheduler 1104 optionally provides 1116 the value of the advance planning time for the new MAC entity as calculated to the CCF 1102.21 4894-4182-1929\1

[0115] Note that that the L3 scheduler 1104 will also communicate the value of the advance planning time for the new MAC entity to the responsible base station for the new MAC entity (not illustrated).

[0116] As seen, the flow diagram 1100 corresponds to a case where resource allocation chains may be updated by appending elements (base stations) to their ends. For such cases, previously established advance planning times for all previously established MAC entity(s) in the system remain unchanged.

[0117] FIG. 12 illustrates a flow diagram 1200 for communications between a CCF 1202 and an L3 scheduler 1204 corresponding to a second option for MAC entity addition, according to embodiments discussed herein.

[0118] First, the CCF 1202 sends 1206 the L3 scheduler 1204 latency requirements for any already existing MAC entities.

[0119] Then, the CCF 1202 creates 1208 a new MAC entity (Mnew). Context information for the new MAC entity may include the constituent base station(s) of the new MAC entity. The CCF 1202 sends 1210 this context information to the L3 scheduler 1204.

[0120] Based on the received context information for the new MAC entity, the L3 scheduler 1204 selects 1212 a responsible base station for the new MAC entity that is one of the base station(s) of the new MAC entity.

[0121] The L3 scheduler 1204 then checks 1214 the resource allocation chain for each of the base station(s) that are in the new MAC entity. For each of these resource allocation chains that does not include the selected responsible base station, the selected responsible base station is added to some location within the resource allocation chain. Note that this location is not (necessarily) at the end of the resource allocation chain.

[0122] Then the L3 scheduler 1204 (re)calculates 1216 the advance planning time for each MAC entity of the system that has at least one base station described by one of the updated resource allocation chains. In other words, the L3 scheduler 1204 calculates an advance planning time for the new MAC entity based on the resource allocation chains for the base station(s) in the new MAC entity, and recalculates any advance planning times for any already existing MAC entity(s) having at least one base station described by one of the updated resource allocation chain(s). These calculations use the resource allocation chains (e.g., as updated) for the base station(s) in each of these MAC entities (e.g., as is described elsewhere herein).22 4894-4182-1929\1

[0123] In some embodiments, the L3 scheduler 1204 optionally provides 1218 the value(s) of the (re)calculated advance planning time(s) as calculated to the CCF 1202.

[0124] Note that that the L3 scheduler 1204 will also communicate the value of each (re)calculated advance planning time for a corresponding MAC entity to the responsible base station for that MAC entity (not illustrated).

[0125] As seen, the flow diagram 1200 corresponds to a case where resource allocation chains are updated not necessarily by appending elements at the end of resource allocation chains (as in FIG. 11), but instead by adding elements at other places in the resource allocation chains. The location for the addition may be determined based on, for example, optimization principles described elsewhere herein. Accordingly, corresponding to such cases, the advance planning times of one or more already existing MAC entity(s) may change.

[0126] FIG. 13 illustrates a flow diagram 1300 for communications between a CCF 1302 and an L3 scheduler 1304 corresponding to an option for MAC entity removal, according to embodiments discussed herein.

[0127] First, the CCF 1302 removes 1306 a MAC entity from use (the removed MAC entity is referred to as an “old MAC entity” and denoted Mold). The CCF 1302 sends 1308 the L3 scheduler 1304 a notification that the old MAC entity has been removed.

[0128] Then, for each of the base station(s) in the old MAC entity, the L3 scheduler 1304 checks 1310 whether any remaining MAC entity to which that base station belongs uses a responsible base station that is the same as the responsible base station of the old MAC entity. If this is not the case, the responsible base station for the old MAC entity is removed from the resource allocation chain for the base station being checked.

[0129] Subsequently, the flow diagram 1300 recalculates 1312 advance planning times for any MAC entity(s) having a base station described by a resource allocation chain that was modified (e.g., as is described elsewhere herein).

[0130] In some embodiments, the L3 scheduler 1304 optionally provides 1314 the value(s) of any (re)calculated advance planning time(s) as calculated to the CCF 1302.

[0131] Note that that the L3 scheduler 1304 will also communicate the value of each (re)calculated advance planning time for a corresponding MAC entity to the responsible base station for that MAC entity (not illustrated).23 4894-4182-1929\1

[0132] Note that under the mechanism just described, advance planning time of various remaining MAC entities can either remain the same or decrease (but will not increase).

[0133] FIG. 14 illustrates a flow diagram 1400 for communications between a CCF 1402 and an L3 scheduler 1404 corresponding to an L3 procedure for reconfiguring resource allocation chains, according to embodiments discussed herein.

[0134] First, the CCF 1402 sends 1406 the L3 scheduler 1404 latency requirements for any existing MAC entity(s).

[0135] Then, the L3 scheduler 1404 selects 1408 a new responsible base station for each of the MAC entity(s) (where it is understood that a prior responsible base station for a given MAC entity in question may in some cases be reselected here). For example, this reconfiguration may occur according to delay for MAC thisreconfiguration may occur according to a trigger corresponding to an identification that / a receipt of an indication that a sum of the advance planning times for the MAC entity(s) has exceeded a threshold. The L3 scheduler 1404 also proceeds to construct resource allocation chains for each of the base stations of the system corresponding to the newly selected responsible base stations for the MAC entities.

[0136] The L3 scheduler 1404 then proceeds to identifies 1410 a TTI during which the newly selected responsible base stations and the newly constructed resource allocation chains should begin to be used. This TTI may be denoted Tnew.

[0137] The L3 scheduler 1404 further recalculates 1412 advance planning time for each of the MAC entity(s) using the newly selected responsible base stations and the newly constructed resource allocation chains (e.g., as is described elsewhere herein).

[0138] In some embodiments, the L3 scheduler 1404 optionally provides 1414 the values of the recalculated advance planning times as calculated and / or an indication of the TTI Tnew to the CCF 1402.

[0139] Note that that the L3 scheduler 1304 will also communicate the value of each recalculated advance planning time for a MAC entity to the responsible base station for that MAC entity (not illustrated).24 4894-4182-1929\1

[0140] A procedure for reconfiguring resource allocation chains can be started periodically (e.g. according to a pre-configured period of time), and / or the use of such reconfiguration may be based on a specific trigger, (e.g., when a value of is identified to be larger than a pre-configured threshold).Embodiments for Real Time Base Station Procedures

[0141] Mechanisms for the input and output of resource allocation decisions at a base station are now discussed. In particular, input and / or output message exchange flows for resource allocation decisions for a base station b are discussed. Base station b may participate in a number of resource allocation chains ( ). Further, base station b may be the responsible base station resource allocation for one or more MAC entities( .

[0142] For each , base station b keeps an up-to-date version of resource . This resource allocation is updated based on the input frompredecessor and based on base station b’s allocation decisions.

[0143] Each TTI, afterare received obtained and processed, for each , the resource allocation procedure is run for a particular TTI in the future. The time of the resource allocation is δ.

[0144] Each TTI, after the resource allocation procedures that started δ TTIs ago are finished for all , for each , the current resource allocation result of resources for allTTIs (for which the allocation result is available at the base station b) is sent to the successor base stations in the resource allocation chains: .

[0145] Further, if the base station b has an allocation decision for its own resources for any TTI T, it implements the decision at this TTI.

[0146] According to this mechanism, it may accordingly be understood that a set of one or more predecessor base stations providing input messages to the base station b is represented as . Further, a set of one or moreb provides output messages is represented as .25 4894-4182-1929\1

[0147] FIG. 15A illustrates a diagram 1502 illustrating the input of previous resource allocation decisions for one or more MAC entities to a base station b 1506 from a set of Prec(b) base stations 1508 and a subsequent output of resource allocation decisions for one or more MAC entities from the base station b 1506 to a set of Succ(b) base stations 1510.

[0148] FIG. 15B illustrates a flow diagram 1504 showing details of the communications between the base station b 1506, the set of Prec(b) base stations 1508, and the set of Succ(b) base stations 1510 corresponding to FIG. 15A.

[0149] As illustrated in FIG. 15B, the set of Prec(b) base stations 1508 sends 1512 the base station b 1506 information of any prior resource allocation decisions for one or more MAC entities. This information may include resource allocation decisions that were taken at any one or more of the set of Prec(b) base stations 1508. This resource allocation information may further include resource allocation decisions that were received at the set of Prec(b) base stations 1508 from still further preceding base stations (e.g., as illustrated in FIG. 15A).

[0150] The base station b 1506 then processes 1514 the received resource allocation decision information. Taking into account the received resource allocation decision information, the base station b 1506 then runs 1516 scheduling to update / create resource allocation decisions. For example, a resource allocation decision for each MAC entity for which the base station b 1506 is responsible is made by the base station b 1506 and is added to the set of resource allocation information as previously received from the set of Prec(b) base stations 1508.

[0151] The base station b 1506 then sends 1518 resource allocation information (e.g., as updated / created at the base station b 1506) to the set of Succ(b) base stations 1510.

[0152] Further, if the base station b 1506 has an allocation decision for its own resources for any TTI T, it executes 1520 this decision at this TTI.

[0153] Note that while in the particular embodiment illustrated in FIG. 15A each of the set of Prec(b) base stations 1508 and the set of Succ(b) base stations 1510 has been illustrated to include multiple base stations, in alternative cases, either / both of these could include only a single base station.

[0154] Mechanisms for real-time scheduling procedures at a base station are now discussed. In particular, a MAC scheduling process and a messaging exchange for resource allocation decisions for a base station b are discussed. Base station b may26 4894-4182-1929\1participate in a number of resource allocation chains ( ). Further, base station b may be the responsible base station for performing resource allocation for one or more MAC entities ( ).

[0155] Each TTI, for , a real-time resource allocation procedure is run for the . Here, Δ is a time for implementationof the scheduling which includes time corresponding to applicable K0 (time slots between a downlink control information (DCI) and an associated physical downlink shared channel (PDSCH) transmission) and K2 (slots between a DCI and an associated physical uplink shared channel (PUSCH) transmission) values for downlink (DL) and uplink (UL) respectively. Note that a time δ for computation of the resource allocation as discussed here may be considered as taken into account in the term.

[0156] In various embodiments, a resource allocation procedure (according to a scheduler) may allocate MACs having a same advance planning time onto resourcesstations for the TTI:does not change any already made allocation for .

[0157] The scheduler may be configured to use information about MAC entities that are supposed to be allocated later onto in order to ensure fairness. For example, the scheduler considers these MAC entities as “virtual MAC entities” (further discussed elsewhere herein) when making allocation decisions.

[0158] Note that based on the nature of the cell-free architecture, a UE might belong to more than one MAC entity. To make it possible to allocate resources without real-time coordination, MAC entities for a same UE agree on a coordinated allocation pattern (in time, frequency or space domain, as described elsewhere herein). These constraints are taken into account by the scheduler when the real-time resource allocation is done.

[0159] Details about the use of virtual MAC entities and related fairness mechanisms are now provided. Consider be the set of MAC entities that are to be allocated by particular basefor a particular TTI in the future. Thus, the advance planning time for all is the same and equal to . Further, consider that.27 4894-4182-1929\1

[0160] Virtual MAC entities may be defined as: , denoting a set of and / or, of least one ofthe MAC entities .

[0161] The schedulerrun at the base station to virtually allocate any remaining / still available resources of for the virtual MAC entities . Note that . After the result of the real-time scheduler is only the allocationfor entities is actually preserved / passed along to any Succ(b) basethat were allocated for are considered as not occupied to this communication.

[0162] FIG. 16A illustrates a network-level view of a wireless communication system 1602 that shows the relation of various MAC entities used by the wireless communication system 1602 and their relation to various base stations. As illustrated, the various MAC entities use various ones of the base stations. For example, as can be seen from the wireless communication system 1602, the MAC entity M11610 includes the base station b01604, the base station b11606, and the base station b21608; the MAC entity M21612 includes the base station b01604 and the base station b11606; the MAC entity M31614 includes the base station b01604 and the base station b11606; and the MAC entity M41616 includes the base station b01604.

[0163] FIG. 16B illustrates a first example 1618 of resource distribution corresponding to the wireless communication system 1602 of FIG. 16A in the case where there is no use of a virtual MAC fairness mechanism. It may be assumed that the resource allocation occurs according to the illustrated resource allocation chain 1620, according to which the allocation order is first the base station b21608, then the base station b11606, then the base station b01604.

[0164] The first base station to make a resource allocation decision according to the resource allocation chain 1620 is the base station b21608. The base station b21608 is the responsible base station for the MAC entity M11610, and accordingly allocates first resources 1622 for the MAC entity M11610 into unused ones of a known set of resource blocks 1624. Note that the base station b21608 uses no virtual MAC consideration 1626 to make its resource allocation decisions, and accordingly does not limit its use of the resource blocks 1624.28 4894-4182-1929\1

[0165] The next base station to make a resource allocation decision according to the resource allocation chain 1620 is the base station b11606. The base station b21608 is the responsible base station for each of the MAC entity M11610 and the MAC entity M2 1612. Accordingly, the base station b11606 allocates second resources 1628 for the MAC entity M21612 into still-unused ones of the known set of resource blocks 1624. However, because the second resources 1628 use up all the remaining resource blocks 1624, the base station b21608 makes no resource allocation for the MAC entity M31614.

[0166] Further, note that the base station b21608 uses no virtual MAC consideration 1630 to make its resource allocation decisions, it does not limit its use of the resource blocks 1624.

[0167] The next base station to make a resource allocation decision according to the resource allocation chain 1620 is the base station b01604. The base station b21608 is the responsible base station for the MAC entity M41616. However, all of the resources of the resource blocks 1624 are already scheduled. Accordingly, the base station b01604 is unable to allocate any resources to the MAC entity M41616.

[0168] It can thus be understood according to FIG. 16B that without the use / consideration of virtual MACs entities, resources may be distributed disproportionally in favor of MAC entities with relatively longer advanced planning times.

[0169] FIG. 16C illustrates second example 1632 of resource distribution corresponding to the wireless communication system 1602 of FIG. 16A in the case where there is a use of a virtual MAC fairness mechanism. It may be again assumed that the resource allocation occurs according to the illustrated resource allocation chain 1620.

[0170] The first base station to make a resource allocation decision according to the resource allocation chain 1620 is the base station b21608. The base station b21608 is the responsible base station for the MAC entity M11610, and accordingly allocates first resources 1634 for the MAC entity M11610 into an unused ones of a known set of resource blocks 1624.

[0171] Note that in this case, the base station b21608 operates according to the use of first virtual MAC entity information 1642. The base station0 b21608 understands from the first virtual MAC entity information 1642 that the MAC entity M21612, the MAC entity M31614, and the MAC entity M41616 still need to be scheduled within the resource blocks 1624 by down-chain base station(s). Accordingly, the base station b229 4894-4182-1929\11608 limits its use of the resource blocks 1624 (compare the allocation of the first resources 1634 in FIG. 16C to the allocation of the first resources 1622 in FIG. 16B).

[0172] The next base station to make a resource allocation decision according to the resource allocation chain 1620 is the base station b11606. The base station b11606 is the responsible base station for each of the MAC entity M21612 and the MAC entity M3 1614. Accordingly, the base station b11606 allocates second resources 1636 for the MAC entity M21612 and third resources 1638 for the MAC entity M31614 into still- unused ones of the known set of resource blocks 1624.

[0173] Note that in this case, the base station b11606 operates according to the use of second virtual MAC entity information 1644. The base station b21608 understands from the second virtual MAC entity information 1644 that the MAC entity M41616 still needs to be scheduled within the resource blocks 1624 by a down-chain base station. Accordingly, the base station b11606 limits its use of the resource blocks 1624 (compare the allocation of the second resources 1636 and the third resources 1638 in FIG. 16C to the allocation of the second resources 1628 in FIG. 16B).

[0174] The next base station to make a resource allocation decision according to the resource allocation chain 1620 is the base station b01604. The base station b01604 is the responsible base station for the MAC entity M41616. Accordingly, the base station b01604 allocates fourth resources 1640 for the fourth resources 1640 into still-unused ones of the known set of resource blocks 1624.

[0175] Note that in this case, the base station b01604 operates according to the use of third virtual MAC entity information 1646. However, the third virtual MAC entity information 1646 indicates that there are no virtual MAC entities remaining to be scheduled by down-chain base station(s). Accordingly, the base station b01604 does not limit its use of the resource blocks 1624.

[0176] It can thus be understood according to FIG. 16C that with the use / consideration of virtual MACs entities, resources may be distributed more fairly among all relevant MAC entities, even in cases where these MAC entities use different advanced planning times.

[0177] In some embodiments using virtual MAC entities, resources are distributed based on a priority strategy. This priority strategy may, in some cases, depend on an applicable advance planning time.30 4894-4182-1929\1

[0178] Mechanisms for real-time scheduling that are consistent with the use of virtual MAC entities are now discussed. In some embodiments, input for the scheduler may be provided as: , where: • to be allocated at a same• denotes base stations and a TTI for which resources are to be . In thisand; • denotes the existing allocation of the resources of , made by base station b or provided by the base stations that precede b in the resource allocation chains. In various embodiments, this allocation is treated as fixed (is not modified at / by base station b); and • denotes the set of virtual MAC entities that participate in the overall resource procedure, where it is understood that resource allocations for these virtual MAC entities are removed / discarded (to free those resources) after the overall resource allocation decision that takes into account the set of virtual MAC entities is made.

[0179] Then, the output of the scheduler may be provided to any down-chain base stations as an updated resource allocation of .

[0180] Each MAC from and / or may beto the scheduler as a structure containing:• Buffer statuses and service histories of the UEs; • PHY measurements and link quality estimations; • Link adaptation and QoS parameters of the UEs; and / or • Restrictions for resource allocation, based on a coordinated allocation pattern.

[0181] FIG. 17 illustrates a method 1700 of a L3 scheduler of a cluster of base stations serving a UE, according to embodiments discussed herein. The method 1700 includes identifying 1702, a first set of responsible base stations from the cluster of base stations, wherein each base station of the first set of responsible base stations is responsible for at least one MAC entity of a set of MAC entities used between the cluster of base stations and the UE, and wherein each MAC entity of the set of MAC entities comprises one or more of the base stations of the cluster. The method 1700 further includes constructing31 4894-4182-1929\11704 a first set of resource allocation chains, wherein each resource allocation chain of the first set of resource allocation chains is for one of the base stations of the cluster. The method 1700 further includes calculating 1706 a first set of advance planning times for the set of MAC entities based on the first set of resource allocation chains, wherein each advance planning time of the first set of advance planning times is for one of the set of MAC entities. The method 1700 further includes providing 1708 the first set of advance planning times for the set of MAC entities to the first set of responsible base stations.

[0182] In some embodiments of the method 1700, each resource allocation chain for each base station of the first set of resource allocation chains is constructed by: identifying a subset of MAC entities of the set of MAC entities that includes the base station that is described by the resource allocation chain; adding each responsible base station of the first set of responsible base stations that is responsible for one or more MAC entities of the subset of MAC entities to the resource allocation chain; and adding the base station for the resource allocation chain to the resource allocation chain. In some such embodiments, the method 1700 further includes sorting the resource allocation chain after adding each responsible base station of the first set of responsible base stations that is responsible for the one or more MAC entities of the subset of MAC entities to the resource allocation chain and prior to adding the base station for the resource allocation chain to the resource allocation chain.

[0183] In some embodiments of the method 1700, each advance planning time for each MAC entity of the first set of advance planning times is calculated by: identifying, from the first set of resource allocation chains, one or more resource allocation chains, the one or more resource allocation chains including each of the first set of resource allocation chains that is used by a base station of the MAC entity; calculating one or more attributable scheduling times for the MAC entity using the one or more resource allocation chains; and selecting a longest attributable scheduling time of the one or more attributable scheduling times for the MAC entity as the advance planning time for the MAC entity. In some such embodiments, each of the one or more attributable scheduling times for the MAC entity are calculated by summing, for each of the one or more resource allocation chains: the total Xn interface latency for Xn interfaces corresponding to a portion of the resource allocation chain that runs from the responsible base station to the base station that is described by the resource allocation chain; and the total scheduling algorithm delay attributable to the use of a scheduling algorithm at each of32 4894-4182-1929\1the first set of responsible base stations that is included in the portion of the resource allocation chain.

[0184] In some embodiments, the method 1700 further includes identifying a trigger indicating that a second set of resource allocation chains should be used; identifying, in response to identifying the trigger, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; constructing, based on receiving the trigger, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculating a second set of advance planning times based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and providing the second set of advance planning times for the set of MAC entities to the second set of responsible base stations. In some such embodiments, the trigger comprises an indication that a sum of the first set of advance planning times has exceeded a threshold.

[0185] In some embodiments, the method 1700 further includes determining that a validity period for the first set of resource allocation chains has expired; identifying, in response to determining that the validity period has expired, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; constructing, based on determining that the validity period has expired, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculating a second set of advance planning times for the set of MAC entities based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and providing the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

[0186] In some embodiments, the method 1700 further includes receiving, from a clustering control function (CCF), a context for a new MAC entity that is to be used by the cluster, the context identifying one or more base stations of the cluster that belong to the new MAC entity; selecting a responsible base station for the new MAC entity; for33 4894-4182-1929\1each of one or more resource allocation chains of the first set of resource allocation chains that is for a base station of the one or more base stations that belong to the new MAC entity: identifying whether the resource allocation chain for the base station includes the responsible base station; and if the resource allocation chain for the base station does not include the responsible base station, adding the responsible base station to the resource allocation chain; calculating an advance planning time for the new MAC entity using the one or more resource allocation chains; and providing the advance planning time for the new MAC entity to the responsible base station for the new MAC entity. In some such embodiments, the method 1700 further includes calculating a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains to which the responsible base station was added; and providing the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

[0187] In some embodiments, the method 1700 further includes receiving, from a CCF, a notification of a first MAC entity of the set of MAC entities that is to be removed from the cluster, wherein the first MAC entity uses a first responsible base station and one or more base stations of the cluster belong to the first MAC entity; for each of the one or more base stations that belongs to the first MAC entity, removing, from a resource allocation chain for the base station, the first responsible base station when no MAC entity of the set of MAC entities other than the first MAC entity to which the base station belongs uses the first responsible base station as its responsible base station; calculating a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains from which the responsible base station was removed; and providing the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

[0188] FIG. 18 illustrates a method 1800 of a first responsible base station that is responsible for a first MAC entity comprising a first plurality of base stations within a cluster of base station serving a UE, according to embodiments discussed herein. The method 1800 includes receiving 1802, from an L3 scheduler, a first advance planning time corresponding to the first MAC entity. The method 1800 includes allocating 1804,34 4894-4182-1929\1to the first MAC entity, first transmission resources at a first target TTI that follows a current TTI by the first advance planning time. The method 1800 further includes sending 1806, to a first successor base station in a first resource allocation chain for a first target base station of the plurality of base stations of the first MAC entity, a first indication of the first transmission resources at the first target TTI that are allocated to the first MAC entity.

[0189] In some embodiments, the method 1800 further includes receiving, from a predecessor base station, a second indication of second transmission resources at the first target TTI that are allocated to a second MAC entity, and wherein the allocation of the first transmission resources at the first target TTI to the first MAC entity does not include the second transmission resources.

[0190] In some embodiments, the method 1800 further includes performing a virtual allocation of second transmission resources at the first target TTI to a virtual MAC entity, wherein the virtual MAC entity represents a second MAC entity that is to be scheduled by a second responsible base station.

[0191] In some embodiments of the method 1800, the first successor base station of the first resource allocation chain is the target base station.

[0192] In some embodiments of the method 1800, the first successor base station of the first resource allocation chain is not included in the MAC entity.

[0193] In some embodiments, the method 1800 further includes sending, to a second successor base station in a second resource allocation chain for a second target base station of the plurality of base stations of the first MAC entity, a second indication of the first transmission resources at the first target TTI that are allocated to the first MAC entity. In some such embodiments, the second successor base station of the second resource allocation chain comprises the second target base station. In some such embodiments, the second successor base station of the second resource allocation chain is not included in the first MAC entity.

[0194] In some embodiments of the method 1800, the first responsible base station is further responsible for a second MAC entity comprising a second plurality of base stations within the cluster of base stations, and the method 1800 further includes: receiving, from the L3 scheduler, a second advance planning time corresponding to the second MAC entity; allocating second transmission resources at a second TTI that follows the current TTI by the second advance planning time to the second MAC entity;35 4894-4182-1929\1and sending, to a second successor base station of a second resource allocation chain for a second target base station of the one or more base stations of the second MAC entity, a second indication of the second transmission resources at the second target TTI that are allocated to the second MAC entity. In some such embodiments, the first MAC entity and the second MAC entity each include a shared base station. In some such embodiments, there is no shared base station between the first MAC entity and the second MAC entity.

[0195] In some embodiments of the method 1800,

[0196] FIG. 19 illustrates an example architecture of a wireless communication system 1900, according to embodiments disclosed herein. The following description is provided for an example wireless communication system 1900 that operates in conjunction with the LTE system standards and / or 5G or NR system standards as provided by 3GPP technical specifications.

[0197] As shown by FIG. 19, the wireless communication system 1900 includes UE 1902 and UE 1904 (although any number of UEs may be used). In this example, the UE 1902 and the UE 1904 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device configured for wireless communication.

[0198] The UE 1902 and UE 1904 may be configured to communicatively couple with a RAN 1906. In embodiments, the RAN 1906 may be NG-RAN, E-UTRAN, etc. The UE 1902 and UE 1904 utilize connections (or channels) (shown as connection 1908 and connection 1910, respectively) with the RAN 1906, each of which comprises a physical communications interface. The RAN 1906 can include one or more base stations (such as base station 1912 and base station 1914) that enable the connection 1908 and connection 1910.

[0199] In this example, the connection 1908 and connection 1910 are air interfaces to enable such communicative coupling, and may be consistent with RAT(s) used by the RAN 1906, such as, for example, an LTE and / or NR.

[0200] In some embodiments, the UE 1902 and UE 1904 may also directly exchange communication data via a sidelink interface 1916. The UE 1904 is shown to be configured to access an access point (shown as AP 1918) via connection 1920. By way of example, the connection 1920 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP 1918 may36 4894-4182-1929\1comprise a Wi-Fi®router. In this example, the AP 1918 may be connected to another network (for example, the Internet) without going through a CN 1924.

[0201] In embodiments, the UE 1902 and UE 1904 can be configured to communicate using orthogonal frequency division multiplexing (OFDM) communication signals with each other or with the base station 1912 and / or the base station 1914 over a multicarrier communication channel in accordance with various communication techniques, such as, but not limited to, an orthogonal frequency division multiple access (OFDMA) communication technique (e.g., for downlink communications) or a single carrier frequency division multiple access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers.

[0202] In some embodiments, all or parts of the base station 1912 or base station 1914 may be implemented as one or more software entities running on server computers as part of a virtual network. In addition, or in other embodiments, the base station 1912 or base station 1914 may be configured to communicate with one another via interface 1922. In embodiments where the wireless communication system 1900 is an LTE system (e.g., when the CN 1924 is an EPC), the interface 1922 may be an X2 interface. The X2 interface may be defined between two or more base stations (e.g., two or more eNBs and the like) that connect to an EPC, and / or between two eNBs connecting to the EPC. In embodiments where the wireless communication system 1900 is an NR system (e.g., when CN 1924 is a 5GC), the interface 1922 may be an Xn interface. The Xn interface is defined between two or more base stations (e.g., two or more gNBs and the like) that connect to 5GC, between a base station 1912 (e.g., a gNB) connecting to 5GC and an eNB, and / or between two eNBs connecting to 5GC (e.g., CN 1924).

[0203] The RAN 1906 is shown to be communicatively coupled to the CN 1924. The CN 1924 may comprise one or more network elements 1926, which are configured to offer various data and telecommunications services to customers / subscribers (e.g., users of UE 1902 and UE 1904) who are connected to the CN 1924 via the RAN 1906. The components of the CN 1924 may be implemented in one physical device or separate physical devices including components to read and execute instructions from a machine- readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium).37 4894-4182-1929\1

[0204] In embodiments, the CN 1924 may be an EPC, and the RAN 1906 may be connected with the CN 1924 via an S1 interface 1928. In embodiments, the S1 interface 1928 may be split into two parts, an S1 user plane (S1-U) interface, which carries traffic data between the base station 1912 or base station 1914 and a serving gateway (S-GW), and the S1-MME interface, which is a signaling interface between the base station 1912 or base station 1914 and mobility management entities (MMEs).

[0205] In embodiments, the CN 1924 may be a 5GC, and the RAN 1906 may be connected with the CN 1924 via an NG interface 1928. In embodiments, the NG interface 1928 may be split into two parts, an NG user plane (NG-U) interface, which carries traffic data between the base station 1912 or base station 1914 and a user plane function (UPF), and the S1 control plane (NG-C) interface, which is a signaling interface between the base station 1912 or base station 1914 and access and mobility management functions (AMFs).

[0206] Generally, an application server 1930 may be an element offering applications that use internet protocol (IP) bearer resources with the CN 1924 (e.g., packet switched data services). The application server 1930 can also be configured to support one or more communication services (e.g., VoIP sessions, group communication sessions, etc.) for the UE 1902 and UE 1904 via the CN 1924. The application server 1930 may communicate with the CN 1924 through an IP communications interface 1932.

[0207] FIG. 20 illustrates a system 2000 for performing signaling 2034 between a wireless device 2002 and a network device 2018 as supported by a CN device 2036, according to embodiments disclosed herein. The system 2000 may be a portion of a wireless communications system as herein described. The wireless device 2002 may be, for example, a UE of a wireless communication system. The network device 2018 may be, for example, a base station (e.g., an eNB, a gNB, or a sixth generation base station) of a wireless communication system.

[0208] The wireless device 2002 may include one or more processor(s) 2004. The processor(s) 2004 may execute instructions such that various operations of the wireless device 2002 are performed, as described herein. The processor(s) 2004 may include one or more baseband processors implemented using, for example, a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware38 4894-4182-1929\1device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0209] The wireless device 2002 may include a memory 2006. The memory 2006 may be a non-transitory computer-readable storage medium that stores instructions 2008 (which may include, for example, the instructions being executed by the processor(s) 2004). The instructions 2008 may also be referred to as program code or a computer program. The memory 2006 may also store data used by, and results computed by, the processor(s) 2004.

[0210] The wireless device 2002 may include one or more transceiver(s) 2010 that may include radio frequency (RF) transmitter circuitry and / or receiver circuitry that use the antenna(s) 2012 of the wireless device 2002 to facilitate signaling (e.g., the signaling 2034) to and / or from the wireless device 2002 with other devices (e.g., the network device 2018) according to corresponding RATs.

[0211] The wireless device 2002 may include one or more antenna(s) 2012 (e.g., one, two, four, or more). For embodiments with multiple antenna(s) 2012, the wireless device 2002 may leverage the spatial diversity of such multiple antenna(s) 2012 to send and / or receive multiple different data streams on the same time and frequency resources. This behavior may be referred to as, for example, MIMO behavior (referring to the multiple antennas used at each of a transmitting device and a receiving device that enable this aspect). MIMO transmissions by the wireless device 2002 may be accomplished according to precoding (or digital beamforming) that is applied at the wireless device 2002 that multiplexes the data streams across the antenna(s) 2012 according to known or assumed channel characteristics such that each data stream is received with an appropriate signal strength relative to other streams and at a desired location in the spatial domain (e.g., the location of a receiver associated with that data stream). Certain embodiments may use single user MIMO (SU-MIMO) methods (where the data streams are all directed to a single receiver) and / or multi user MIMO (MU-MIMO) methods (where individual data streams may be directed to individual (different) receivers in different locations in the spatial domain).

[0212] In certain embodiments having multiple antennas, the wireless device 2002 may implement analog beamforming techniques, whereby phases of the signals sent by the antenna(s) 2012 are relatively adjusted such that the (joint) transmission of the antenna(s) 2012 can be directed (this is sometimes referred to as beam steering).39 4894-4182-1929\1

[0213] The wireless device 2002 may include one or more interface(s) 2014. The interface(s) 2014 may be used to provide input to or output from the wireless device 2002. For example, a wireless device 2002 that is a UE may include interface(s) 2014 such as microphones, speakers, a touchscreen, buttons, and the like in order to allow for input and / or output to the UE by a user of the UE. Other interfaces of such a UE may be made up of transmitters, receivers, and other circuitry (e.g., other than the transceiver(s) 2010 / antenna(s) 2012 already described) that allow for communication between the UE and other devices and may operate according to known protocols (e.g., Wi-Fi®, Bluetooth®, and the like).

[0214] The wireless device 2002 may include a MAC scheduling module 2016. The MAC scheduling module 2016 may be implemented via hardware, software, or combinations thereof. For example, the MAC scheduling module 2016 may be implemented as a processor, circuit, and / or instructions 2008 stored in the memory 2006 and executed by the processor(s) 2004. In some examples, the MAC scheduling module 2016 may be integrated within the processor(s) 2004 and / or the transceiver(s) 2010. For example, the MAC scheduling module 2016 may be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the processor(s) 2004 or the transceiver(s) 2010.

[0215] The MAC scheduling module 2016 may configure the wireless device 2002 to be used for various aspects of the present disclosure, for example, aspects corresponding to the use of communications using MAC entities as scheduled, in the manner discussed herein.

[0216] The network device 2018 may include one or more processor(s) 2020. The processor(s) 2020 may execute instructions such that various operations of the network device 2018 are performed, as described herein. The processor(s) 2020 may include one or more baseband processors implemented using, for example, a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0217] The network device 2018 may include a memory 2022. The memory 2022 may be a non-transitory computer-readable storage medium that stores instructions 2024 (which may include, for example, the instructions being executed by the processor(s) 2020). The instructions 2024 may also be referred to as program code or a computer40 4894-4182-1929\1program. The memory 2022 may also store data used by, and results computed by, the processor(s) 2020.

[0218] The network device 2018 may include one or more transceiver(s) 2026 that may include RF transmitter circuitry and / or receiver circuitry that use the antenna(s) 2028 of the network device 2018 to facilitate signaling (e.g., the signaling 2034) to and / or from the network device 2018 with other devices (e.g., the wireless device 2002) according to corresponding RATs.

[0219] The network device 2018 may include one or more antenna(s) 2028 (e.g., one, two, four, or more). In embodiments having multiple antenna(s) 2028, the network device 2018 may perform MIMO, digital beamforming, analog beamforming, beam steering, etc., as has been described.

[0220] The network device 2018 may include one or more interface(s) 2030. The interface(s) 2030 may be used to provide input to or output from the network device 2018. For example, a network device 2018 that is a base station may include interface(s) 2030 made up of transmitters, receivers, and other circuitry (e.g., other than the transceiver(s) 2026 / antenna(s) 2028 already described) that enables the base station to communicate with other equipment in a core network, and / or that enables the base station to communicate with external networks, computers, databases, and the like for purposes of operations, administration, and maintenance of the base station or other equipment operably connected thereto. As another example, the network device 2018 may communicate with the CN device 2036 on an interface 2048 of the interface(s) 2030 (which, in, for example, NR cases, may be an NG interface or in LTE cases may be an S1 interface).

[0221] The network device 2018 may include a MAC scheduling module 2032. The MAC scheduling module 2032 may be implemented via hardware, software, or combinations thereof. For example, the MAC scheduling module 2032 may be implemented as a processor, circuit, and / or instructions 2024stored in the memory 2022 and executed by the processor(s) 2020. In some examples, the MAC scheduling module 2032 may be integrated within the processor(s) 2020 and / or the transceiver(s) 2026. For example, the MAC scheduling module 2032 may be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the processor(s) 2020 or the transceiver(s) 2026.41 4894-4182-1929\1

[0222] The MAC scheduling module 2032 may configure the network device 2018 to be used for various aspects of the present disclosure, for example, aspects of FIG. 17 and / or FIG. 18. In some embodiments, the MAC scheduling module 2032 may configure the network device 2018 to work with and / or as part of an L3 scheduler to identify responsible base stations, to construct a set of resource allocation chains, to calculate advance planning times, and / or to provide advance planning times to any responsible base stations. In some embodiments, the MAC scheduling module 2032 may configure the network device 2018 to receive, from an L3 scheduler, an advance planning time for a MAC entity, allocate to the first MAC entity, transmission resources at a target TTI, and / or to send, to a successor base station, an indication of the transmission resources as allocated.

[0223] The CN device 2036 may include one or more processor(s) 2038. The processor(s) 2038 may execute instructions such that various operations of the CN device 2036 are performed, as described herein. The processor(s) 2038 may include one or more baseband processors implemented using, for example, a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0224] The CN device 2036 may include a memory 2040. The memory 2040 may be a non-transitory computer-readable storage medium that stores instructions 2042 (which may include, for example, the instructions being executed by the processor(s) 2038). The instructions 2042 may also be referred to as program code or a computer program. The memory 2040 may also store data used by, and results computed by, the processor(s) 2038.

[0225] The CN device 2036 may include one or more interface(s) 2044. The interface(s) 2044 may be used to provide input to or output from the CN device 2036. For example, a CN device 2036 may communicate with the network device 2018 on an interface 2048 of the interface(s) 2044 (which, in, for example, NR cases, may be an NG interface or in LTE cases may be an S1 interface).

[0226] The CN device 2036 may include a MAC scheduling module 2046. The MAC scheduling module 2046 may be implemented via hardware, software, or combinations thereof. For example, the MAC scheduling module 2046 may be implemented as a processor, circuit, and / or instructions 2042 stored in the memory 2040 and executed by the processor(s) 2038. In some examples, the MAC scheduling module 2046 may be42 4894-4182-1929\1integrated within the processor(s) 2038. For example, the MAC scheduling module 2046 may be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the processor(s) 2038.

[0227] The MAC scheduling module 2046 may configure the CN device 2036 to be used for various aspects of the present disclosure, for example, aspects of FIG. 17. In some embodiments, the MAC scheduling module 2046 may configure the network CN device 2036 to work with and / or as part of an L3 scheduler to identify responsible base stations, to construct a set of resource allocation chains, to calculate advance planning times, and / or to provide advance planning times to any responsible base stations.

[0228] Embodiments contemplated herein include an apparatus comprising means to perform one or more elements of any of the method 1700 and the method 1800. This apparatus may be, for example, an apparatus of a base station (such as a network device 2018 that is a base station, as described herein).

[0229] Embodiments contemplated herein include one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of any of the method 1700 and the method 1800. This non-transitory computer-readable media may be, for example, a memory of a base station (such as a memory 2022 of a network device 2018 that is a base station, as described herein).

[0230] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry to perform one or more elements of any of the method 1700 and the method 1800. This apparatus may be, for example, an apparatus of a base station (such as a network device 2018 that is a base station, as described herein).

[0231] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of any of the method 1700 and the method 1800. This apparatus may be, for example, an apparatus of a base station (such as a network device 2018 that is a base station, as described herein).

[0232] Embodiments contemplated herein include a signal as described in or related to one or more elements of any of the method 1700 and the method 1800.43 4894-4182-1929\1

[0233] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processing element is to cause the processing element to carry out one or more elements of any of the method 1700 and the method 1800. The processor may be a processor of a base station (such as a processor(s) 2020 of a network device 2018 that is a base station, as described herein). These instructions may be, for example, located in the processor and / or on a memory of the base station (such as a memory 2022 of a network device 2018 that is a base station, as described herein).

[0234] Embodiments contemplated herein include an apparatus comprising means to perform one or more elements of the method 1700. This apparatus may be, for example, an apparatus of a base station (such as a network device 2018 that is a base station, as described herein) and / or of a CN (such as the CN device 2036, as described herein). It is further contemplated that this apparatus may be one of many such apparatuses working together in a distributed fashion to perform the one or more elements of the method 1700.

[0235] Embodiments contemplated herein include one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of the method 1700. This non-transitory computer- readable media may be, for example, a memory of a base station (such as a memory 2040 of a network device 2018 that is a base station, as described herein) and / or of a CN (such as the memory 2040 of a CN device 2036, as described herein). It is further contemplated that the electronic device may be one of many such electronic devices working together in a distributed fashion to perform the one or more elements of the method 1700.

[0236] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry to perform one or more elements of the method 1700. This apparatus may be, for example, an apparatus of a base station (such as a network device 2018 that is a base station, as described herein) and / or of a CN (such as the CN device 2036, as described herein). It is further contemplated that this apparatus may be one of many such apparatuses working together in a distributed fashion to perform the one or more elements of the method 1700.44 4894-4182-1929\1

[0237] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of the method 1700. This apparatus may be, for example, an apparatus of a base station (such as a network device 2018 that is a base station, as described herein) and / or of a CN (such as the CN device 2036, as described herein). It is further contemplated that this apparatus may be one of many such apparatuses working together in a distributed fashion to perform the one or more elements of the method 1700.

[0238] Embodiments contemplated herein include a signal as described in or related to one or more elements of the method 1700.

[0239] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processing element is to cause the processing element to carry out one or more elements of the method 1700. The processor may be a processor of a base station (such as a processor(s) 2020 of a network device 2018 that is a base station, as described herein). These instructions may be, for example, located in the processor and / or on a memory of the base station (such as a memory 2022 of a network device 2018 that is a base station, as described herein). The processor may be a processor of a CN device (such as a processor(s) 2038 of a CN device 2036, as described herein). These instructions may be, for example, located in the processor and / or on a memory of the CN device (such as a memory 2040 of a CN device 2036, as described herein). It is further contemplated that the processing element may be one of many such processing elements working together in a distributed fashion to perform the one or more elements of the method 1700.

[0240] For one or more embodiments, at least one of the components set forth in one or more of the preceding figures may be configured to perform one or more operations, techniques, processes, and / or methods as set forth herein. For example, a baseband processor as described herein in connection with one or more of the preceding figures may be configured to operate in accordance with one or more of the examples set forth herein. For another example, circuitry associated with a UE, base station, network element, etc. as described above in connection with one or more of the preceding figures may be configured to operate in accordance with one or more of the examples set forth herein.45 4894-4182-1929\1

[0241] Any of the above described embodiments may be combined with any other embodiment (or combination of embodiments), unless explicitly stated otherwise. The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.

[0242] Embodiments and implementations of the systems and methods described herein may include various operations, which may be embodied in machine-executable instructions to be executed by a computer system. A computer system may include one or more general-purpose or special-purpose computers (or other electronic devices). The computer system may include hardware components that include specific logic for performing the operations or may include a combination of hardware, software, and / or firmware.

[0243] It should be recognized that the systems described herein include descriptions of specific embodiments. These embodiments can be combined into single systems, partially combined into other systems, split into multiple systems or divided or combined in other ways. In addition, it is contemplated that parameters, attributes, aspects, etc. of one embodiment can be used in another embodiment. The parameters, attributes, aspects, etc. are merely described in one or more embodiments for clarity, and it is recognized that the parameters, attributes, aspects, etc. can be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment unless specifically disclaimed herein.

[0244] It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

[0245] Although the foregoing has been described in some detail for purposes of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles thereof. It should be noted that there are many alternative ways of implementing both the processes and apparatuses described herein. Accordingly, the present embodiments are to be considered illustrative and not restrictive, and the46 4894-4182-1929\1description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.47 4894-4182-1929\1

Claims

CLAIMS 1. A method of a layer 3 (L3) scheduler of a cluster of base stations serving a user equipment (UE), comprising: identifying a first set of responsible base stations from the cluster of base stations, wherein each base station of the first set of responsible base stations is responsible for at least one medium access control (MAC) entity of a set of MAC entities used between the cluster of base stations and the UE, and wherein each MAC entity of the set of MAC entities comprises one or more of the base stations of the cluster; constructing a first set of resource allocation chains, wherein each resource allocation chain of the first set of resource allocation chains is for one of the base stations of the cluster; calculating a first set of advance planning times for the set of MAC entities based on the first set of resource allocation chains, wherein each advance planning time of the first set of advance planning times is for one of the set of MAC entities; and providing the first set of advance planning times for the set of MAC entities to the first set of responsible base stations.

2. The method of claim 1, wherein each resource allocation chain for each base station of the first set of resource allocation chains is constructed by: identifying a subset of MAC entities of the set of MAC entities that includes the base station that is described by the resource allocation chain; adding each responsible base station of the first set of responsible base stations that is responsible for one or more MAC entities of the subset of MAC entities to the resource allocation chain; and adding the base station for the resource allocation chain to the resource allocation chain.

3. The method of claim 2, further comprising sorting the resource allocation chain after adding each responsible base station of the first set of responsible base stations that is responsible for the one or more MAC entities of the subset of MAC entities to the resource allocation chain and prior to adding the base station for the resource allocation chain to the resource allocation chain.48 4894-4182-1929\14. The method of claim 1, wherein each advance planning time for each MAC entity of the first set of advance planning times is calculated by: identifying, from the first set of resource allocation chains, one or more resource allocation chains, the one or more resource allocation chains including each of the first set of resource allocation chains that is used by a base station of the MAC entity; calculating one or more attributable scheduling times for the MAC entity using the one or more resource allocation chains; and selecting a longest attributable scheduling time of the one or more attributable scheduling times for the MAC entity as the advance planning time for the MAC entity.

5. The method of claim 4, wherein each of the one or more attributable scheduling times for the MAC entity are calculated by summing, for each of the one or more resource allocation chains: the total Xn interface latency for Xn interfaces corresponding to a portion of the resource allocation chain that runs from the responsible base station to the base station that is described by the resource allocation chain; and the total scheduling algorithm delay attributable to the use of a scheduling algorithm at each of the first set of responsible base stations that is included in the portion of the resource allocation chain.

6. The method of claim 1, further comprising: identifying a trigger indicating that a second set of resource allocation chains should be used; identifying, in response to identifying the trigger, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; constructing, based on receiving the trigger, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculating a second set of advance planning times based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and49 4894-4182-1929\1providing the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

7. The method of claim 6, wherein the trigger comprises an indication that a sum of the first set of advance planning times has exceeded a threshold.

8. The method of claim 1, further comprising: determining that a validity period for the first set of resource allocation chains has expired; identifying, in response to determining that the validity period has expired, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; constructing, based on determining that the validity period has expired, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculating a second set of advance planning times for the set of MAC entities based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and providing the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

9. The method of claim 1, further comprising: receiving, from a clustering control function (CCF), a context for a new MAC entity that is to be used by the cluster, the context identifying one or more base stations of the cluster that belong to the new MAC entity; selecting a responsible base station for the new MAC entity; for each of one or more resource allocation chains of the first set of resource allocation chains that is for a base station of the one or more base stations that belong to the new MAC entity: identifying whether the resource allocation chain for the base station includes the responsible base station; and50 4894-4182-1929\1if the resource allocation chain for the base station does not include the responsible base station, adding the responsible base station to the resource allocation chain; calculating an advance planning time for the new MAC entity using the one or more resource allocation chains; and providing the advance planning time for the new MAC entity to the responsible base station for the new MAC entity.

10. The method of claim 9, further comprising: calculating a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains to which the responsible base station was added; and providing the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

11. The method of claim 1, further comprising: receiving, from a clustering control function (CCF), a notification of a first MAC entity of the set of MAC entities that is to be removed from the cluster, wherein the first MAC entity uses a first responsible base station and one or more base stations of the cluster belong to the first MAC entity; for each of the one or more base stations that belongs to the first MAC entity, removing, from a resource allocation chain for the base station, the first responsible base station when no MAC entity of the set of MAC entities other than the first MAC entity to which the base station belongs uses the first responsible base station as its responsible base station; calculating a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains from which the responsible base station was removed; and providing the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.51 4894-4182-1929\112. A non-transitory computer-readable storage medium including instructions that when executed by an L3 scheduler, cause the L3 scheduler to: identify a first set of responsible base stations from the cluster of base stations, wherein each base station of the first set of responsible base stations is responsible for at least one medium access control (MAC) entity of a set of MAC entities used between the cluster of base stations and the UE, and wherein each MAC entity of the set of MAC entities comprises one or more of the base stations of the cluster; construct a first set of resource allocation chains, wherein each resource allocation chain of the first set of resource allocation chains is for one of the base stations of the cluster; calculate a first set of advance planning times for the set of MAC entities based on the first set of resource allocation chains, wherein each advance planning time of the first set of advance planning times is for one of the set of MAC entities; and provide the first set of advance planning times for the set of MAC entities to the first set of responsible base stations.

13. The non-transitory computer-readable storage medium of claim 12, wherein each resource allocation chain for each base station of the first set of resource allocation chains is constructed by: identifying a subset of MAC entities of the set of MAC entities that includes the base station that is described by the resource allocation chain; adding each responsible base station of the first set of responsible base stations that is responsible for one or more MAC entities of the subset of MAC entities to the resource allocation chain; and adding the base station for the resource allocation chain to the resource allocation chain.

14. The non-transitory computer-readable storage medium of claim 13, wherein the instructions further cause the L3 scheduler to sort the resource allocation chain after adding each responsible base station of the first set of responsible base stations that is responsible for the one or more MAC entities of the subset of MAC entities to the resource allocation chain and prior to adding the base station for the resource allocation chain to the resource allocation chain.52 4894-4182-1929\115. The non-transitory computer-readable storage medium of claim 12, wherein each advance planning time for each MAC entity of the first set of advance planning times is calculated by: identifying, from the first set of resource allocation chains, one or more resource allocation chains, the one or more resource allocation chains including each of the first set of resource allocation chains that is used by a base station of the MAC entity; calculating one or more attributable scheduling times for the MAC entity using the one or more resource allocation chains; and selecting a longest attributable scheduling time of the one or more attributable scheduling times for the MAC entity as the advance planning time for the MAC entity.

16. The non-transitory computer-readable storage medium of claim 15, wherein each of the one or more attributable scheduling times for the MAC entity are calculated by summing, for each of the one or more resource allocation chains: the total Xn interface latency for Xn interfaces corresponding to a portion of the resource allocation chain that runs from the responsible base station to the base station that is described by the resource allocation chain; and the total scheduling algorithm delay attributable to the use of a scheduling algorithm at each of the first set of responsible base stations that is included in the portion of the resource allocation chain.

17. The non-transitory computer-readable storage medium of claim 12, wherein the instructions further cause the L3 scheduler to: identify a trigger indicating that a second set of resource allocation chains should be used; identify, in response to identifying the trigger, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; construct, based on receiving the trigger, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster;53 4894-4182-1929\1calculate a second set of advance planning times based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and provide the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

18. The non-transitory computer-readable storage medium of claim 17, wherein the trigger comprises an indication that a sum of the first set of advance planning times has exceeded a threshold.

19. The non-transitory computer-readable storage medium of claim 12, wherein the instructions further cause the L3 scheduler to: determine that a validity period for the first set of resource allocation chains has expired; identify, in response to determining that the validity period has expired, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; construct, based on determining that the validity period has expired, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculate a second set of advance planning times for the set of MAC entities based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and provide the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

20. The non-transitory computer-readable storage medium of claim 12, wherein the instructions further cause the L3 scheduler to: receive, from a clustering control function (CCF), a context for a new MAC entity that is to be used by the cluster, the context identifying one or more base stations of the cluster that belong to the new MAC entity; select a responsible base station for the new MAC entity;54 4894-4182-1929\1for each of one or more resource allocation chains of the first set of resource allocation chains that is for a base station of the one or more base stations that belong to the new MAC entity: identify whether the resource allocation chain for the base station includes the responsible base station; and if the resource allocation chain for the base station does not include the responsible base station, add the responsible base station to the resource allocation chain; calculate an advance planning time for the new MAC entity using the one or more resource allocation chains; and provide the advance planning time for the new MAC entity to the responsible base station for the new MAC entity.

21. The non-transitory computer-readable storage medium of claim 20, wherein the instructions further cause the L3 scheduler to: calculate a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains to which the responsible base station was added; and provide the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

22. The non-transitory computer-readable storage medium of claim 12, wherein the instructions further cause the L3 scheduler to: receive, from a clustering control function (CCF), a notification of a first MAC entity of the set of MAC entities that is to be removed from the cluster, wherein the first MAC entity uses a first responsible base station and one or more base stations of the cluster belong to the first MAC entity; for each of the one or more base stations that belongs to the first MAC entity, remove, from a resource allocation chain for the base station, the first responsible base station when no MAC entity of the set of MAC entities other than the first MAC entity to which the base station belongs uses the first responsible base station as its responsible base station;55 4894-4182-1929\1calculate a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains from which the responsible base station was removed; and provide the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

23. An apparatus of an L3 scheduler, comprising: one or more processors; and a memory storing instructions that, when executed by the one or more processors, configure the L3 scheduler to: identify a first set of responsible base stations from the cluster of base stations, wherein each base station of the first set of responsible base stations is responsible for at least one medium access control (MAC) entity of a set of MAC entities used between the cluster of base stations and the UE, and wherein each MAC entity of the set of MAC entities comprises one or more of the base stations of the cluster; construct a first set of resource allocation chains, wherein each resource allocation chain of the first set of resource allocation chains is for one of the base stations of the cluster; calculate a first set of advance planning times for the set of MAC entities based on the first set of resource allocation chains, wherein each advance planning time of the first set of advance planning times is for one of the set of MAC entities; and provide the first set of advance planning times for the set of MAC entities to the first set of responsible base stations.

24. The apparatus of claim 23, wherein each resource allocation chain for each base station of the first set of resource allocation chains is constructed by: identifying a subset of MAC entities of the set of MAC entities that includes the base station that is described by the resource allocation chain;56 4894-4182-1929\1adding each responsible base station of the first set of responsible base stations that is responsible for one or more MAC entities of the subset of MAC entities to the resource allocation chain; and adding the base station for the resource allocation chain to the resource allocation chain.

25. The apparatus of claim 24, wherein the instructions further cause the L3 scheduler to sort the resource allocation chain after adding each responsible base station of the first set of responsible base stations that is responsible for the one or more MAC entities of the subset of MAC entities to the resource allocation chain and prior to adding the base station for the resource allocation chain to the resource allocation chain.

26. The apparatus of claim 23, wherein each advance planning time for each MAC entity of the first set of advance planning times is calculated by: identifying, from the first set of resource allocation chains, one or more resource allocation chains, the one or more resource allocation chains including each of the first set of resource allocation chains that is used by a base station of the MAC entity; calculating one or more attributable scheduling times for the MAC entity using the one or more resource allocation chains; and selecting a longest attributable scheduling time of the one or more attributable scheduling times for the MAC entity as the advance planning time for the MAC entity.

27. The apparatus of claim 26, wherein each of the one or more attributable scheduling times for the MAC entity are calculated by summing, for each of the one or more resource allocation chains: the total Xn interface latency for Xn interfaces corresponding to a portion of the resource allocation chain that runs from the responsible base station to the base station that is described by the resource allocation chain; and the total scheduling algorithm delay attributable to the use of a scheduling algorithm at each of the first set of responsible base stations that is included in the portion of the resource allocation chain.

28. The apparatus of claim 23, wherein the instructions further configure the L3 scheduler to:57 4894-4182-1929\1identify a trigger indicating that a second set of resource allocation chains should be used; identify, in response to identifying the trigger, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; construct, based on receiving the trigger, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculate a second set of advance planning times based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and provide the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

29. The apparatus of claim 28, wherein the trigger comprises an indication that a sum of the first set of advance planning times has exceeded a threshold.

30. The apparatus of claim 23, wherein the instructions further configure the L3 scheduler to: determine that a validity period for the first set of resource allocation chains has expired; identify, in response to determining that the validity period has expired, a second set of responsible base stations from the cluster of base stations, wherein each base station of the second set of responsible base stations is responsible for at least one MAC entity of the set of MAC entities; construct, based on determining that the validity period has expired, a second set of resource allocation chains, wherein each resource allocation chain of the second set of resource allocation chains is for one of the base stations of the cluster; calculate a second set of advance planning times for the set of MAC entities based on the second set of resource allocation chains, wherein each advance planning time of the second set of advance planning times is for one of the set of MAC entities; and58 4894-4182-1929\1provide the second set of advance planning times for the set of MAC entities to the second set of responsible base stations.

31. The apparatus of claim 23, wherein the instructions further configure the L3 scheduler to: receive, from a clustering control function (CCF), a context for a new MAC entity that is to be used by the cluster, the context identifying one or more base stations of the cluster that belong to the new MAC entity; select a responsible base station for the new MAC entity; for each of one or more resource allocation chains of the first set of resource allocation chains that is for a base station of the one or more base stations that belong to the new MAC entity: identify whether the resource allocation chain for the base station includes the responsible base station; and if the resource allocation chain for the base station does not include the responsible base station, add the responsible base station to the resource allocation chain; calculate an advance planning time for the new MAC entity using the one or more resource allocation chains; and provide the advance planning time for the new MAC entity to the responsible base station for the new MAC entity.

32. The apparatus of claim 31, wherein the instructions further configure the L3 scheduler to: calculate a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains to which the responsible base station was added; and provide the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

33. The apparatus of claim 23, wherein the instructions further configure the L3 scheduler to: receive, from a clustering control function (CCF), a notification of a first MAC entity of the set of MAC entities that is to be removed from the cluster, wherein the first59 4894-4182-1929\1MAC entity uses a first responsible base station and one or more base stations of the cluster belong to the first MAC entity; for each of the one or more base stations that belongs to the first MAC entity, remove, from a resource allocation chain for the base station, the first responsible base station when no MAC entity of the set of MAC entities other than the first MAC entity to which the base station belongs uses the first responsible base station as its responsible base station; calculate a second set of advance planning times for one or more MAC entities of the set of MAC entities that include a base station that is described by one of the one or more resource allocation chains from which the responsible base station was removed; and provide the second set of advance planning times to one or more responsible base stations of the set of responsible base stations that is responsible for the one or more MAC entities.

34.

22. An apparatus comprising means to perform the method of any of claim 1 to claim 11.

35. A computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform the method of any of claim 1 to claim 11.

36. An apparatus comprising logic, modules, or circuitry to perform the method of any of claim 1 to claim 11.

37. A baseband processor for a base station that is configured to cause the base station to perform one or more elements of any one of claim 1 to claim 11.60 4894-4182-1929\1

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