Systems and methods for determining base station sets for resource allocation grants in cell-free communications

Abstract

Systems and methods for determining base station sets for resource allocation grants in cell-free communications are disclosed herein. A medium access control (MAC) scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a user equipment (UE) determines that a base station set within the MAC entity cannot transmit a physical downlink control channel (PDCCH) using a given aggregation level to meet a minimum power level corresponding to the first aggregation level, adds a base station to the base station set, determines that the base station set can transmit the PDCCH at the aggregation level to meet the minimum power level corresponding to the aggregation level, and transmits the PDCCH to the UE using the base station set at the aggregation level. Analogous mechanisms based on calculated probabilities instead of per-aggregation-level power levels is also discussed.

Description

SYSTEMS AND METHODS FOR DETERMINING BASE STATION SETS FOR RESOURCE ALLOCATION GRANTS IN CELL-FREE COMMUNICATIONS TECHNICAL FIELD

[0001] This application relates generally to wireless communication systems, including cell-free wireless communication systems. BACKGROUND

[0002] Wireless mobile communication technology uses various standards and protocols to transmit data between a base station 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 P60803WO14882-1915-6730\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 showing a UE and a first base station, a second base station, and a third base station of a RAN.

[0009] FIG. 2 illustrates a diagram showing a case of mobility of a UE within a RAN that includes a first base station, a second base station, a third base station, a fourth base station, a fifth base station, a sixth base station, and a seventh base station and that operates according to a cell-based network architecture.

[0010] FIG. 3 illustrates a diagram showing a case of mobility of a UE within a RAN that includes a first base station, a second base station, a third base station, a fourth base station, a fifth base station, a sixth base station, and a seventh base station and that operates according to a cell-free network architecture.

[0011] FIG. 4 illustrates a diagram for an example of clustering in a cell-free network architecture, according to embodiments discussed herein.

[0012] FIG. 5 illustrates a diagram showing a portion of a protocol stack and its visualized application within a cluster serving a UE, corresponding to a case of MAC scheduling using joint decision making, according to embodiments discussed herein.

[0013] FIG. 6 illustrates a diagram showing a portion of a protocol stack and its visualized application within a cluster, corresponding to a case of MAC scheduling using centralized decision making, according to embodiments discussed herein.2 P60803WO14882-1915-6730\1

[0014] FIG. 7 illustrates a diagram showing a portion of a protocol stack and its visualized application within a cluster, corresponding to a case of MAC scheduling using mixed mode decision making, according to embodiments discussed herein.

[0015] FIG. 8A illustrates a flow diagram showing an RRC message exchange for configuring a CORESET corresponding to a MAC entity as between a UE and a cell-free network, according to embodiments discussed herein.

[0016] FIG. 8B illustrates a flow diagram showing a MAC CE indication of a maximum number of PDCCHs (corresponding to DCIs / TBs) that can be allocated by a MAC as between a UE and a cell-free network, according to embodiments discussed herein.

[0017] FIG. 9 illustrates a diagram 900 showing a scheduler that schedules a UE according to a MAC entity used by a cluster of a cell-free network, according to embodiments discussed herein.

[0018] FIG. 10 illustrates a flowchart for a method to identify one or more base station(s) and a corresponding aggregation level at which to transmit a grant to a UE, according to embodiments discussed herein.

[0019] FIG. 11A illustrates a first graph of individual receive power levels experienced at a UE from each of four base stations of a MAC entity, according to embodiments discussed herein.

[0020] FIG. 11B illustrates a second graph of receive power levels experienced at a UE based on various combinations of base stations of a MAC entity.

[0021] FIG. 11C illustrates a third graph of receive power levels experienced at a UE based on various combinations of base stations of a MAC entity.

[0022] FIG. 12 illustrates a flowchart for a method to identify one or more base station(s) and a corresponding aggregation level at which to transmit a grant to a UE, according to embodiments discussed herein.

[0023] FIG. 13A illustrates a first graph of individual transmission success probabilities from each of four base stations of a MAC entity, according to embodiments discussed herein.

[0024] FIG. 13B illustrates a second graph of transmission success probabilities of various combinations of base stations of a MAC entity.3 P60803WO14882-1915-6730\1

[0025] FIG. 14 illustrates a diagram of various bandwidths within time-frequency resources used by various base stations of a wireless communication system, according to embodiments discussed herein.

[0026] FIG. 15 illustrates a cell-free MAC entity that uses a first base station, a second base station, a third base station, and a fourth base station to communicate with a UE, according to embodiments discussed herein.

[0027] FIG. 16 illustrates a method of a MAC scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a UE, according to embodiments herein.

[0028] FIG. 17 illustrates a method of a MAC scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a UE, according to embodiments herein.

[0029] FIG. 18 illustrates a method of a UE that is served by a cluster of base stations, according to embodiments herein.

[0030] FIG. 19 illustrates a method of a UE that is served by a cluster of base stations, according to embodiments herein.

[0031] FIG. 20 illustrates a method of a cluster of base stations serving a UE, according to embodiments herein.

[0032] FIG. 21 illustrates a method of a UE that is served by a cluster of base stations, according to embodiments herein.

[0033] FIG. 22 illustrates a method of a cluster of base stations serving a UE, according to embodiments herein.

[0034] FIG. 23 illustrates an example architecture of a wireless communication system, according to embodiments disclosed herein.

[0035] FIG. 24 illustrates a system for performing signaling between a wireless device and a network device, according to embodiments disclosed herein. DETAILED DESCRIPTION

[0036] 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 and4 P60803WO14882-1915-6730\1data with the network. Therefore, the UE as described herein is used to represent any appropriate electronic component.

[0037] In some wireless communications systems (e.g., 3GPP NR and LTE), when a UE is in coverage, it is attached to a “serving cell.” Further, system information (SI) and paging messages as well as control signaling are initiated at a primary cell, regardless of the presence and / or number of other serving cells.

[0038] In dual connectivity (DC) contexts, a similar concept exists; there is a primary serving cell, and if the UE loses connection with that primary serving cell, it is considered out-of-coverage. It is the primary serving cell which provides SI messages to and configures the UE.

[0039] FIG. 1 illustrates a diagram 100 showing a UE 102 and a first base station 104, a second base station 106, and a third base station 108 of a RAN. As illustrated in FIG. 1, the UE 102 presently uses a serving cell that is served by a first base station 104.

[0040] Corresponding to this depiction, it may be understood that the cell(s) of the network that are available to the UE 102 belong to / that are broadcast by one of the first base station 104, the second base station 106, and the third base station 108. Accordingly, it should be understood that the cell(s) to which the UE may be connected may be located at various / different physical locations.

[0041] FIG. 2 illustrates a diagram 200 showing a case of mobility 222 of a UE 202 within a RAN that includes a first base station 204, a second base station 206, a third base station 208, a fourth base station 210, a fifth base station 212, a sixth base station 214, and a seventh base station 216 and that operates according to a cell-based network architecture. As illustrated, a first mobility management entity (MME) 218 manages mobility aspects with respect to the first base station 204, the second base station 206, the fourth base station 210, and the seventh base station 216, while a second MME 220 manages mobility aspects with respect to the third base station 208, the fifth base station 212, and the sixth base station 214.

[0042] As illustrated in FIG. 2, when the UE 202 is at a first location 224 corresponding to first time, it uses a cell of the first base station 204 as a serving cell. In multiple connectivity cases, it may be that cells of the second base station 206, the third base station 208, and / or the fourth base station 210 also exchange data with this UE as secondary cells (non-serving cells). At the first time, the UE 202 receives SI, paging5 P60803WO14882-1915-6730\1messages, and / or configuration signaling from its serving cell at the first base station 204.

[0043] Then the UE undergoes the illustrated mobility 222, with the result that the UE 202 is at the second location 226 at a second time. Attendant to this mobility 222, the UE performs a handover to a new serving cell at the seventh base station 216, (meaning that the UE stops using the cell of the first base station 204 as its serving cell and instead uses a (different) cell at the seventh base station 216 as its serving cell, as illustrated). Thus, at the second time, the UE 202 receives SI signaling, paging messages, and / or configuration signaling from the new serving cell at the seventh base station 216.

[0044] The need to have a serving cell, to perform measurements regularly, to switch serving cells (for example due to mobility), etc., consumes considerable UE power. This may drain a battery of the UE (assuming a case of a battery-powered UE). Furthermore, any handover procedure may cause service interruptions and sometimes even connection failure. It should also be noted that, with respect to cases corresponding to a potential for the use of a relatively larger number of secondary cells, measurement overhead for purposes of cell evaluation attendant to potential handovers to a new serving cell increases as the number of secondary cells grows.

[0045] In some wireless 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 one or more physically and / or logically connected base stations over which functionalities related to 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.

[0046] 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.6 P60803WO14882-1915-6730\1

[0047] The use of a cell-free network architecture may result in a reduction of higher layer signaling between the UE and the network and / or an overall improvement of physical link quality between the UE and the network. Under a cell-free architecture, when the UE is in the radio resource control (RRC) idle (RRC_IDLE) state or an RRC inactive (RRC_INACTIVE) state, the UE may receive SI messages from whatever cells that, public land mobile network (PLMN)-wise and access-wise are allowed.

[0048] However, when the UE is in the RRC connected (RRC_CONNECTED) state, functionalities associated with a serving cell as understood in the context of prior cell- based network architectures are distributed over the user-centric cluster of base stations. Within the cluster, the network creates one or more (cell-free) medium access control (MAC) entities and associates each of these with some subset of the base stations in the cluster. Each such MAC entity is assumed to be able to allocate resources of its base stations and send a corresponding grant to the UE.

[0049] FIG. 3 illustrates a diagram 300 showing a case of mobility 322 of a UE 302 within a RAN that includes a first base station 304, a second base station 306, a third base station 308, a fourth base station 310, a fifth base station 312, a sixth base station 314, and a seventh base station 316 and that operates according to a cell-free network architecture. As illustrated, a first MME 318 manages mobility aspects with respect to the first base station 304, the second base station 306, the fourth base station 310, and the seventh base station 316, while a second MME 320 manages mobility aspects with respect to the third base station 308, the fifth base station 312, and the sixth base station 314.

[0050] As illustrated in FIG. 3, when the UE 302 is at a first location 326 corresponding to a first time, it connects to the network through the first cluster 324. Note that in this case, there is no one particular cell of any of the first base station 304, the second base station 306, the third base station 308, and the fourth base station 310 that acts as a serving cell; rather, serving functions (SI signaling, paging messages, and / or configuration signaling, etc.) are provided at the UE at the level of the first cluster 324 and across the first base station 304, the second base station 306, the third base station 308, and the fourth base station 310 collectively.

[0051] Then the UE undergoes the illustrated mobility 322, with the result that the UE 302 is at the second location 328 at a second time. Attendant to this mobility 322, the UE then connects to the network through a second cluster 330 that includes the third base7 P60803WO14882-1915-6730\1station 308, the fourth base station 310, the fifth base station 312, the sixth base station 314, and the seventh base station 316. Thus, at the second time, the UE 202 is provided serving functions such as SI signaling, paging messages, and / or configuration signaling, etc., at the level of the second cluster 330, across the third base station 308, the fourth base station 310, the fifth base station 312, the sixth base station 314, and the seventh base station 316 collectively.

[0052] FIG. 4 illustrates a diagram 400 for an example of clustering in a cell-free network architecture, according to embodiments discussed herein. A first cluster 402 of base stations serves a first UE 404 and a second cluster 406 of base stations serves the second UE 408. As illustrated, the first cluster 402 includes the first base stations 410 and the second base stations 412, while the second cluster 406 includes the second base stations 412 and the third base station 414.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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 may8 P60803WO14882-1915-6730\1include corresponding functionalities, protocols, message exchange capabilities, and the like supporting the use of clustering as described herein.

[0057] 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).

[0058] 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 of Cell-Free MAC Scheduling

[0059] MAC scheduling as used within cell-free networks having characteristics described herein are now discussed. MAC scheduling may be performed by a MAC entity. A MAC entity may be understood to serve one or more radio link control (RLC) entity(s) (and thus one or more sub-cluster(s)). The MAC entity can operate with respect to one, some, and / or all of the base stations for an RLC / sub-cluster that it serves (as the case may be). A MAC entity as described herein may be responsible for performing MAC scheduling across its constituent base stations corresponding to a data packet received from an RLC entity that the MAC entity serves.

[0060] A first option for MAC scheduling may be referred to as “joint decision making.” In joint decision-making cases, a MAC resource allocation decision is made jointly / collectively by all of the base stations in a sub-cluster.

[0061] FIG. 5 illustrates a diagram 500 showing a portion of a protocol stack 502 and its visualized application within a cluster 504 serving a UE 506, corresponding to a case of MAC scheduling using joint decision making, according to embodiments discussed herein. As illustrated, the cluster 504 uses the first base station 514 (BS1), the second base station 516 (BS2), and the third base station 518 (BS3) to serve the UE 506.

[0062] The diagram 500 illustrates a packet data convergence protocol (PDCP) entity 508 corresponding to a radio bearer that is served by an RLC entity 510 representing a9 P60803WO14882-1915-6730\1sub-cluster that includes each of the first base station 514 (BS1), the second base station 516 (BS2), and the third base station 518 (BS3), in the manner discussed herein.

[0063] The diagram 500 further illustrates that the RLC entity 510 is itself served by a MAC entity 512 that can perform MAC scheduling using the first base station 514, the second base station 516, and the third base station 518. Note that the bounds of the MAC entity 512 as illustrated in the cluster 504 may be understood directly in terms of the MAC entity 512 rather than the RLC entity 510 (though these bounds are co-extensive in this case).

[0064] An example of joint decision making is now described. An initial decision is made by one of the base stations (e.g., the first base station 514) and provided to the other base stations (e.g., the second base station 516 and the third base station 518) (e.g., via Xn interface). In some cases, several rounds of similar message exchange are possible. At the minimum, at least one round of message exchange is used. Accordingly, it will be understood that in joint decision-making cases, a resource allocation decision can be made for a transition time interval (TTI) that is in the future by at least an Xn latency time corresponding to the at least one round of message exchange. Therefore, the use of joint decision making may be understood to add an Xn latency to a scheduling latency for the MAC entity 512.

[0065] Joint decision making may accordingly be understood to enable a high spectral efficiency across the first base station 514, the second base station 516, and the third base station 518 at the cost of additional MAC scheduling latency. It may therefore be a good choice for cases of latency-tolerant traffic.

[0066] A second option for MAC scheduling may be referred to as “centralized decision making.” In centralized decision-making cases, a resource allocation decision is made in a decentralized manner by the base stations across the different sub-clusters.

[0067] FIG. 6 illustrates a diagram 600 showing a portion of a protocol stack 602 and its visualized application within a cluster 604, corresponding to a case of MAC scheduling using centralized decision making, according to embodiments discussed herein. As illustrated, the cluster 604 uses the first base station 614 (BS1), the second base station 620 (BS2), and the third base station 626 (BS3) to serve the UE 606.

[0068] The diagram 600 illustrates a PDCP entity 608 corresponding to a radio bearer that is served by a first RLC entity 610 representing a first sub-cluster that includes the first base station 614 (BS1), a second RLC entity 616 representing a second sub-cluster10 P60803WO14882-1915-6730\1that includes the second base station 620 (BS2), and a third RLC entity 622 representing a third sub-cluster that includes the third base station 626 (BS3), in the manner discussed herein.

[0069] The diagram 600 further illustrates that first RLC entity 610 is itself served by a first MAC entity 612 that can perform MAC scheduling using the first base station 614, that the second RLC entity 616 is served by a second MAC entity 618 that can perform MAC scheduling using the second base station 620, and that the third RLC entity 622 is served by a third MAC entity 624 that can perform MAC scheduling using the third base station 626. Note that the bounds of each of the first MAC entity 612, the second MAC entity 618, and the third MAC entity 624 as illustrated in the cluster 604 should be understood directly in terms of the respective MAC entity rather than bounds of any corresponding RLC entity (though the MAC entity bounds are co-extensive to the corresponding RLC entity bounds in this case).

[0070] An example of centralized decision making is now described. The first base station 614, the second base station 620, and the third base station 626 agree to a resource-sharing pattern (in the time, frequency and / or spatial domain(s)) for a period of time. For example, they may agree to let each base station K as selected from the first base station 614, the second base station 620, and the third base station 626 schedule the UE 606 in TTIs T such that T mod 3 = K (where K is a different integer value from 1 to 3 corresponding to the three base stations under discussion).

[0071] In another example, in the case that the UE 606 is a multi-antenna UE, the first base station 614, the second base station 620, and the third base station 626 may agree to a split of the frequency band and / or spatial domain as between the first base station 614, the second base station 620, and / or the third base station 626.

[0072] Then, each of the first base station 614, the second base station 620, and the third base station 626 decides (e.g., in real time) to schedule the UE 606 in a manner that complies with the resource-sharing pattern. These decisions may be taken autonomously at each base station (without a need to check with and / or gain consensus from any other base station).

[0073] Decentralized decision making may accordingly be understood not to incur the additional latency penalty that is described herein in relation to the joint decision-making case, but might ultimately achieve less spectral efficiency as compared with the joint decision-making case.11 P60803WO14882-1915-6730\1

[0074] A third option for MAC scheduling may be referred to as “semi-decentralized decision making” or “mixed mode decision making.” In mixed mode decision making cases, a resource allocation decision is made in a mixed-mode / semi-decentralized manner that uses joint decision making between base stations within a sub-cluster and further uses decentralized decision making across the different sub-clusters.

[0075] FIG. 7 illustrates a diagram 700 showing a portion of a protocol stack 702 and its visualized application within a cluster 704, corresponding to a case of MAC scheduling using mixed mode decision making, according to embodiments discussed herein. As illustrated, the cluster 704 uses the first base station 714 (BS1), the second base station 720 (BS2), and the third base station 722 (BS3) to serve the UE 706.

[0076] The diagram 700 illustrates a PDCP entity 708 corresponding to a radio bearer that is served by a first RLC entity 710 representing a first sub-cluster that includes the first base station 714 (BS1) and the second base station 720 (BS2), and a second RLC entity 716 representing a second sub-cluster that includes the third base station 722 (BS3), in the manner discussed herein.

[0077] The diagram 700 further illustrates that first RLC entity 710 is itself served by a first MAC entity 712 that can perform MAC scheduling using the first base station 714 and the second base station 720 and that the second RLC entity 716 is served by a second MAC entity 718 that can perform MAC scheduling using the third base station 722. Note that the bounds of each of the first MAC entity 712 and the second MAC entity 718 as illustrated in the cluster 704 should be understood directly in terms of the respective MAC entity (rather than bounds of any corresponding RLC entity). While in this case the first MAC entity 712 covers all base stations of the sub-cluster of the first RLC entity 710, 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).

[0078] Under mixed mode decision making, a joint decision-making resource allocation occurs as between base stations that belong to the same sub-cluster (independently of other base stations of other different sub-cluster(s)). For example, the first base station 714 and the second base station 720 that are within the sub-cluster corresponding to the first RLC entity 710 might use a message exchange (e.g., analogously to the joint decision making mechanism of FIG. 5) to coordinate their transmissions when they are simultaneously used for joint MAC scheduling (e.g., as may be the case according to the12 P60803WO14882-1915-6730\1first MAC entity 712). This message exchange / coordination may occur without a check to and / or consensus from any base station from outside of the cluster (such as the third base station 722).

[0079] Further, base stations across different sub-clusters might agree to a resource- sharing pattern (in the time, frequency and / or spatial domain(s)) for a period of time that is used as between those base stations, where the resources are split on a MAC entity basis. For example, the base stations of the first MAC entity 712 (the first base station 714 and the second base station 720) might agree with the base stations of the second MAC entity 718 (the third base station 722) on a resource-sharing pattern (in the time, frequency, and / or spatial domain(s)) for a period of time that splits resources as between the first MAC entity 712 and the second MAC entity 718 (e.g., analogously to the decentralized decision making mechanism of FIG. 6).

[0080] It may be understood that a use of a joint decision making resource allocation task at the sub-cluster level may involve a more tolerable / lower Xn latency / MAC scheduling latency penalty incurred as between the base stations of the sub-cluster than that which may be incurred in the alternative case of joint decision making across all base stations of the full cluster (as was described in relation to FIG. 5). Further, due to the use of MAC-level decentralized resource allocation, spectral efficiency across the cluster may be improved at least somewhat over a case where decentralized decision making is taken at each individual base station of the full cluster, as was described in relation to FIG. 6. Accordingly, the mixed mode decision making mechanism may be understood to provide a trade-off between the competing spectral efficiency and latency considerations under discussion.

[0081] Note that in cases where, as illustrated in FIG. 7, there is a single radio bearer in use at the cluster, in order to implement mixed mode decision making, it is sufficient to have MAC entities and RLC entities in a 1-1 correspondence with MAC entities associated with the entire set of base stations of the corresponding RLC entity. However, support for the use of mixed mode decision making in cases corresponding to larger degrees of freedom within the cluster (for example, where there are multiple radio bearers using different RLC entities arranged according to differing sub-cluster partitionings, where MAC entities may or may not be coextensive with an RLC entity that they serve) may involve further considerations.13 P60803WO14882-1915-6730\1

[0082] Embodiments herein describe procedures, mechanisms, and protocols for supporting the use of joint decision making, decentralized decision making, and / or mixed mode decision making within a cluster that account for degrees of freedom in the cluster with respect to, for example, a number of radio bearers, the sub-cluster partitionings for each radio bearer, whether a MAC entity serving an RLC entity is coextensive with that RLC entity, etc. Procedures for the creation of multiple MAC entities that may be used to support joint decision making, decentralized decision making, and / or mixed decision-making options of MAC scheduling for one or multiple data radio bearers (DRBs) of the UE are discussed. Aspects of MAC entity to RLC entity connectivity are discussed. Examples for the simultaneous operation of several MAC entities, including grant allocation concepts, are discussed. Mechanisms for the near real- time activation and / or deactivation of MAC entity to RLC entity connections that take into account UE capabilities and avoid blockages of DRB traffic are discussed. Finally, aspects with respect to coordination between different MAC entities are discussed. Physical Downlink Control Channel (PDCCH) Configuration for Multiple Transport Blocks (TBs) / Grants

[0083] It is contemplated that in some embodiments, each MAC entity might be configured to correspond to a specific control resource set (CORESET) that is used to provide a UE with control information. In such cases, it may further be that a MAC entity provides more than one UL grant (or more than one DL TB allocation) for a same TTI. In this case, the MAC entity allocates a corresponding number of PDCCH / DCI in the CORESET search space for that MAC.

[0084] Thus, a UE may search for PDCCHs in a CORESET corresponding to a MAC entity up to the maximum number of PDCCHs for that MAC entity. This process may be repeated for each MAC entity at the UE.

[0085] It is contemplated that a maximum number of PDCCHs for a MAC entity may be provided to a UE in various different ways, including, for example, via RRC signaling and / or MAC control element (MAC CE) signaling.

[0086] A DCI of a PDCCH may, in some cases, include an indication about an actual number of PDCCHs for the UE in the considered CORESET that may be less than the maximum number of PDCCHs for that CORESET. This indication may accordingly be used to reduce the complexity of PDCCH search at the UE, as the UE can stop14 P60803WO14882-1915-6730\1performing PDCCH searching in the CORESET once this actual number of PDCCHs has been identified in the CORESET.

[0087] FIG. 8A illustrates a flow diagram 800 showing an RRC message exchange for configuring a CORESET corresponding to a MAC entity as between a UE 802 and a cell-free network 804, according to embodiments discussed herein. Note that the cell- free network 804 may operate as indicated through, for example, a cluster of base stations of the cell-free network 804 that is serving the UE 802.

[0088] The flow diagram 800 illustrates that the cell-free network 804 sends the UE 802 a first RRC message 806 that configures the correspondence of CORESET to a particular MAC entity to the UE. Then, the cell-free network 804 sends the UE 802 a second RRC message 808 indicating a maximum number of PDCCHs that may be found in that CORESET. Accordingly, the UE is aware of and is equipped to search for (up to) the maximum number of PDCCHs for the MAC corresponding to that CORESET.

[0089] FIG. 8B illustrates a flow diagram 810 showing a MAC CE indication of a maximum number of PDCCHs (corresponding to DCIs / TBs) that can be allocated by a MAC as between a UE 802 and a cell-free network 804, according to embodiments discussed herein. Note that the cell-free network 804 may operate as indicated through, for example, a cluster of base stations of the cell-free network 804 that is serving the UE 802.

[0090] The flow diagram 800 illustrates that a MAC entity 814 (from the side of the cell-free network 804) sends a MAC CE 812 to the (same) MAC entity 814 (on the side of the MAC entity 814). This MAC CE 812 includes a maximum number of PDCCHs for the MAC entity 814 that may be found in the CORESET for the MAC entity 814.

[0091] Various embodiments disclosed herein discuss solutions for communicating grants that specify UE allocations over downlink control channels. For example, embodiments disclosed herein provide detail on how the network can select base station(s) that transmit grants, carrier frequency and bandwidth allocation mechanisms for grants, options for an entity that creates a payload of the grants, options for transmitting grants, and options for grant reception processing. Base Stations to Transmit Grants

[0092] As is also discussed elsewhere herein, a MAC entity used by a UE under a cell- free architecture might include multiple base stations. In such cases, a multi-base-station15 P60803WO14882-1915-6730\1(and multi-user) MAC scheduler may be used to decide when transmissions and / or receptions should be granted to the UE. Such grants may be understood to be transmitted in, for example, a PDCCH to the UE.

[0093] FIG. 9 illustrates a diagram 900 showing a MAC scheduler 906 that schedules a UE 904 according to a MAC entity 902 used by a cluster of a cell-free network, according to embodiments discussed herein. As illustrated, the MAC entity 902 includes the first base station 908, the second base station 910, the third base station 912, and the fourth base station 914. Thus, with respect to data flowing through the MAC entity 902, the MAC scheduler 906 may be understood to schedule one or more of the first base station 908, the second base station 910, the third base station 912, and / or the fourth base station 914.

[0094] Base stations that transmit grants of transmissions and / or receptions to the UE may be selected by a MAC scheduler according to various criteria. In some examples, a MAC scheduler may select all of the base stations associated with a MAC entity to transmit one or more grants. For example, with respect to the MAC entity 902 illustrated in the diagram 900, the MAC scheduler 906 may select each of the first base station 908, the second base station 910, the third base station 912, and the fourth base station 914 for use for transmitting one or more grants to the UE 904.

[0095] In some examples, fewer than all of the base stations in a MAC entity to use to transmit one or more grants to the UE. The base stations to use may be selected, for example, at random. The number of the base stations selected can range from 1 to n – 1, where n is the number of base stations in the MAC. For example, with respect to the diagram 900, up to three of the first base station 908, the second base station 910, the third base station 912, and / or the fourth base station 914 may be (randomly) selected for use to transmit one or more grants to the diagram 900 (note that n = 4 corresponding to the MAC entity 902 of the diagram 900).

[0096] In some examples, the MAC scheduler may cause the base stations to take turns (e.g., one at a time) transmitting grants to a UE. For example, with respect to the diagram 900, the MAC scheduler 906 may cause a first grant to be transmitted by the first base station 908, then cause a second grant to be transmitted to the UE 904 by the second base station 910, then cause a third grant to be transmitted to the UE 904 by the third base station 912, and then cause a fourth grant to be transmitted to the UE 904 by the fourth base station 914.16 P60803WO14882-1915-6730\1

[0097] In some examples, some subset (including, e.g., an improper subset) of the base stations in the MAC may be selected to transmit a grant to the UE 904 by using a particularized algorithm (examples of which are described herein).

[0098] It is noted that cases of grant combining (where a grant is transmitted to a UE using more than one base station) are not limited to power addition in baseband. It is contemplated that other forms of combining (e.g., log-likelihood ratio combining) may be used.

[0099] An algorithm that may be used (e.g., by a MAC scheduler) to determine a set of one or more “best” base stations in a MAC entity to use to transmit one or more grants to a UE is now discussed.

[0100] When using multiple base stations to transmit a same grant, it should be understood that signals from different cells may be received at different power levels (e.g., signal to noise ratio (SNR) levels) at the UE, due to differences in distance and / or characteristics of the applicable physical channels between the base stations and the UE.

[0101] It should further be understood that a grant can be transmitted at different aggregation levels. As may be understood by those of skill in the art, a relatively higher aggregation level may correspond to a use of relatively more signaling resources for the transmission of the grant. This means that a grant transmitted according to a relatively higher aggregation level can use a relatively more robust encoding within those signaling resources, thus relatively improving a likelihood that the grant is decodable at the UE. It may therefore be understood that any particular selection of an aggregation level represents a “tradeoff” decision between signaling capacity and signaling reliability.

[0102] An applicable mathematical framework is now discussed. A noise power level experienced by a UE may be denoted N0. Then, it may be understood that a minimum receive power at the UE in order to successfully decode a grant is SNRi+ N0+ g, where SNRi is a minimum signal-to-noise ratio at which a UE can decode a grant at a particular aggregation level i, and where g is a guard power value (e.g., to compensate for non- idealities, interference, etc.).

[0103] At high level, algorithms discussed herein may be used to find the minimum number of base station(s) needed to transmit grants such that grants can be successfully decoded, to identify those grant-transmitting base stations, and to find an aggregation level that is correspondingly needed.17 P60803WO14882-1915-6730\1

[0104] FIG. 10 illustrates a flowchart 1000 for a method to identify one or more base station(s) and a corresponding aggregation level at which to transmit a grant to a UE, according to embodiments discussed herein. The method may be implemented by a MAC scheduler for a MAC entity, as is discussed herein.

[0105] For a given set of base station(s), the method shown by the flowchart 1000 determines whether a particular available aggregation level can lead to successful decoding of grants. As part of this procedure, the power of the grant as sent by the base station(s) is checked against associated minimum power level for each of the available aggregation levels (e.g., SNRi + N0 + g as calculated for each aggregation level). If no such minimum power level for any available aggregation level can be met by sending the grant using the set of base stations, then a next strongest base station is added to the set of base stations, and a search for an appropriate aggregation level restarts. Accordingly, aggregation levels are checked and base stations are added until the receive power meets and / or exceeds the minimum required power for successful decoding of the grant at the UE per the aggregation level under consideration.

[0106] A detailed discussion of the flowchart 1000 is now provided. First, a MAC scheduler for the MAC entity under consideration chooses 1002 a strongest base station (e.g., a base station for which the UE has a best reference signal receive power (RSRP), as may have been previously reported to the network by the UE) to use in a set of base stations. Then, the MAC scheduler starts 1004 at a lowest available / useable aggregation level (e.g., aggregation level 1) and then determines 1006 whether or not a grant transmitted with the current set of base stations (e.g., the strongest base station) using that aggregation level meets a minimum power level corresponding to that aggregation level (e.g., SNRi+ N0+ g for that aggregation level).

[0107] In the event that the minimum power level for the present aggregation level is met, then the MAC scheduler uses 1008 the current set of base stations and the present aggregation level to transmit the grant to the UE, and the method of the flowchart 1000 ends.

[0108] In the event that the minimum power level for the present aggregation level is not met, then the MAC scheduler determines 1010 whether a next higher aggregation level to the present aggregation level exists (e.g., aggregation level 2). If so, the MAC scheduler selects 1012 this next higher aggregation level and returns to determine 1006 whether or not a grant transmitted with the current set of base stations meets a minimum18 P60803WO14882-1915-6730\1power level for the (new) aggregation level (which is, for example, different than the minimum power level previously checked for the prior aggregation level, due to the changed minimum power level that is applicable for the new aggregation level).

[0109] As before, in the event that the minimum power level for the present (new) aggregation level is met, then the MAC scheduler uses 1008 the current set of base stations and the present aggregation level to transmit the grant to the UE, and the method of the flowchart 1000 ends. If not, the MAC scheduler proceeds to check for any next higher aggregation level to the present aggregation level and, if found, tests the receive power for the grant as transmitted with the current set of base stations against the applicable minimum power level for that aggregation level, as previously described.

[0110] This action may be further repeated (additional aggregation levels may be checked) until either a workable aggregation level for the present base station set is found (thereby ending the method of the flowchart 1000) or until all available aggregation levels have been tested with the present base station set.

[0111] In the event that the result of these repetitions is that the MAC scheduler determines that no available aggregation level is workable with respect to the present set of base stations, the MAC scheduler determines 1014 whether or not any additional base stations of the cluster are not yet part of the set of base stations being tested. If not, the MAC scheduler concludes 1018 that the grant will not be transmitted (at least in this TTI).

[0112] If there are additional base stations of the cluster that are not yet part of the set of base stations being tested, the MAC scheduler adds 1016 the next strongest base station for the UE that is not yet part of the set of base stations to the set of base stations. Then, the MAC scheduler again starts 1004 from the lowest aggregation level and moves up through the available aggregation levels checking for a workable aggregation level with the set of base stations, as previously described.

[0113] This action may be further repeated (additional base stations may be added to the set of base stations being checked against the available aggregation levels) until either a workable aggregation level / base station set combination is found (thereby ending the method of the flowchart 1000) or until there are no more base stations available for addition to the base station set.

[0114] It is noted that the method of the flowchart 1000 is applicable / useable regardless of beamforming (it is applicable in all frequency bands). In some embodiments, the19 P60803WO14882-1915-6730\1network has the option to limit the maximum aggregation level (e.g., as in the case of 3GPP NR Rel-17 where valid aggregation levels may be limited to 1, 2, 4, 8, and 16).

[0115] FIG. 11A illustrates a first graph 1100 of individual receive power levels experienced at a UE from each of four base stations of a MAC entity, according to embodiments discussed herein. As illustrated in FIG. 11A, the UE experiences a first receive power level 1102 ("P1") from a first base station 1104 ("1"), a second receive power level 1106 ("P2") from a second base station 1108 ("2"), a third receive power level 1110 ("P3") from a third base station 1112 ("3"), and a fourth receive power level 1114 ("P4") from a fourth base station 1116 ("4"). As illustrated, none of the first receive power level 1102, the second receive power level 1106, the third receive power level 1110, and the fourth receive power level 1114 is individually sufficient to reach an aggregation level 1 minimum power level 1118.

[0116] FIG. 11B illustrates a second graph 1120 of receive power levels experienced at a UE based on various combinations of base stations of a MAC entity. FIG. 11B assumes the case of the UE, the MAC entity (including the base stations 1104, 1108, 1112, and 1116 along with their corresponding receive power levels 1102, 1106, 1110, and 1114), and the aggregation level 1 minimum power level 1118 as were described in relation to FIG. 11A.

[0117] For the case corresponding to the second graph 1120 of FIG. 11B, it is assumed that the only available aggregation level is aggregation level 1. Accordingly, the aggregation level 1 minimum power level 1118 is the only minimum power level in play as the system proceeds through the described method.

[0118] Per the method of the flowchart 1000, the MAC scheduler will repeatedly add base stations to a base station set until a calculated power level for the base station set reaches a minimum power level for an aggregation level that is in play (in the case of FIG. 11B, only aggregation level 1 is available).

[0119] Under these circumstances, the MAC scheduler places the strongest base station (e.g., the third base station 1112, see FIG. 11A) into the set of base stations. The MAC scheduler then generates a first calculated power level 1122 for the set of base stations. The first calculated power level 1122 is equal to the third receive power level 1110 of the third base station 1112 that is currently alone in the set of base stations, as illustrated.

[0120] By comparing the first calculated power level 1122 to the aggregation level 1 minimum power level 1118, the MAC scheduler determines that the set of base stations20 P60803WO14882-1915-6730\1cannot transmit a grant according to aggregation level 1 such that the aggregation level 1 minimum power level 1118 is met.

[0121] As there are no additional aggregation levels to check, the MAC scheduler proceeds to place the next strongest base station (e.g., the first base station 1104, see FIG. 11A) into the set of base stations. The MAC scheduler then generates a second calculated power level 1124 for the set of base stations. The second calculated power level 1124 is calculated as a combination of the third receive power level 1110 and the first receive power level 1102 of the third base station 1112 and the first base station 1104 that are each in the set of base stations. Note that due to the physical placement / arrangement of each of the third base station 1112 and the first base station 1104 relative to the UE, the third receive power level 1110 of the third base station 1112 and the first receive power level 1102 of the first base station 1104 may not combine linearly from the perspective of the UE (as can be seen by comparing the third receive power level 1110 of the third base station 1112 and the first receive power level 1102 of the first base station 1104 to the second calculated power level 1124).

[0122] By comparing the second calculated power level 1124 to the aggregation level 1 minimum power level 1118, the MAC scheduler determines that the set of base stations cannot transmit a grant according to aggregation level 1 such that the aggregation level 1 minimum power level 1118 is met.

[0123] Again, as there are no additional aggregation levels to check with the set of base stations as currently constituted, the MAC scheduler proceeds to place the next strongest base station (e.g., the fourth base station 1116, see FIG. 11A) into the set of base stations. The MAC scheduler then generates a third calculated power level 1126 for the set of base stations. The third calculated power level 1126 calculated as to a combination of the third receive power level 1110, the first receive power level 1102, and the fourth receive power level 1114 of the third base station 1112, the first base station 1104, and the fourth base station 1116 that are each in the set of base stations. Again, due to the physical placement / arrangement of each of the base stations, the combination may not be linear from the perspective of the UE.

[0124] By comparing the third calculated power level 1126 to the aggregation level 1 minimum power level 1118, the MAC scheduler determines that the set of base stations can transmit a grant according to aggregation level 1 such that the aggregation level 1 minimum power level 1118 is met. The method then ends, and the MAC scheduler21 P60803WO14882-1915-6730\1proceeds to schedule the grant for transmission at aggregation level 1 by (jointly) each of the third base station 1112, the first base station 1104, and the fourth base station 1116.

[0125] Note that FIG. 11B further illustrates a fourth calculated power level 1128 representing the receive power level at the UE corresponding to all base stations of the MAC entity, consistent with principles discussed herein. However, note that in the applied case just described, the method of the flowchart 1000 does not actually reach this calculation prior to ending.

[0126] FIG. 11C illustrates a third graph 1130 of receive power levels experienced at a UE based on various combinations of base stations of a MAC entity. FIG. 11C assumes the case of the UE, the MAC entity (including the base stations 1104, 1108, 1112, and 1116 along with their corresponding receive power levels 1102, 1106, 1110, and 1114) as were described in relation to FIG. 11A and FIG. 11B.

[0127] For the case corresponding to the second graph 1120 of FIG. 11C, it is assumed that the available aggregation levels go up to aggregation level 2 (e.g., each of aggregation level 1 and aggregation level 2 are available). For illustration purposes, the aggregation level 2 minimum power level 1132 (which is lower than the aggregation level 1 minimum power level 1118) is illustrated in FIG. 11C.

[0128] Under these circumstances, the MAC scheduler places the strongest base station (e.g., the third base station 1112, see FIG. 11A) into the set of base stations. The MAC scheduler then generates a first calculated power level 1122 for the set of base stations. The first calculated power level 1122 is equal to the third receive power level 1110 of the third base station 1112 that is currently alone in the set of base stations, as illustrated.

[0129] By comparing the first calculated power level 1122 to the aggregation level 1 minimum power level 1118 (see FIG. 11B), the MAC scheduler determines that the set of base stations cannot transmit a grant according to aggregation level 1 such that the aggregation level 1 minimum power level 1118 is met.

[0130] However, in this case (differently from the case of FIG. 11B), aggregation level 2 is also available. Accordingly, the MAC scheduler compares the first calculated power level 1122 to the aggregation level 2 minimum power level 1132 and determines that the set of base stations can transmit a grant according to aggregation level 2 such that the aggregation level 2 minimum power level 1132 is met (as illustrated). The method then ends, and the MAC scheduler proceeds to schedule the grant for transmission at aggregation level 2 by the third base station 1112 (alone) in the set of base station.22 P60803WO14882-1915-6730\1

[0131] Note that FIG. 11C further illustrates the second calculated power level 1124, the third calculated power level 1126, and the fourth calculated power level 1128 representing the receive power level at the UE corresponding to combinations of base stations of the MAC entity that would be subsequently used if needed, consistent with principles discussed herein. However, note that in the applied case just described, the method of the flowchart 1000 does not actually reach these calculations prior to ending.

[0132] In some embodiments, combining methods for domains other than the power domain may be used. An example method for the case of log-likelihood ratio (LLR) domain combining at the receiver / UE is now discussed.

[0133] Let K be equal to the total number of base stations in a MAC entity. Consider a vector of received powers at the UE for the base stations (P1, …, PK) , where the power values are expressed in natural units, and where a power to zero ifthe corresponding base station does not transmit a PDCCH / grant.

[0134] The network considers the dependency of decoding probability Prob on the vector of cell received powers according to: , wherelevel under consideration. The function is assumed to be non- decreasing in every variable P1, …, PK.

[0135] Then, a threshold Thprob for the method is configured to the MAC scheduler (e.g., by a CCF). Thprobmay be set in terms of the expected range of values of Prob. A PDCCH / grant may be transmitted in the case that the MAC scheduler determines that ≥ Thprob.

[0136] FIG. 12 illustrates a flowchart 1200 for a method to identify one or more base station(s) and a corresponding aggregation level at which to transmit a grant to a UE, according to embodiments discussed herein. The method may be implemented by a MAC scheduler for a MAC entity, as is discussed herein.

[0137] For a given set of base station(s), the method shown by the flowchart 1200 determines whether a particular available aggregation level can lead to successful decoding of grants. As part of this procedure, the associated probability that the UE willsuccessfully decode the grant ( at the given aggregation23 P60803WO14882-1915-6730\1level) is checked. If Thprob cannot be met for any such value at any available aggregation level by sending the grant using the set of base stations at that aggregation level, then a next strongest base station is added to the set of base stations, and a search for an appropriate aggregation level restarts. Accordingly, aggregation levels are checked and base stations are added until the calculated probability meets and / or exceeds Thprob for the aggregation level under consideration.

[0138] A detailed discussion of the flowchart 1200 is now provided. First, a MAC scheduler for the MAC entity under consideration chooses 1202 a strongest base station (e.g., a base station for which the UE has a best reference signal receive power (RSRP), as may have been previously reported to the network by the UE) to use in a set of base stations. Then, the MAC scheduler starts 1204 at a lowest available / useable aggregation level (e.g., aggregation level 1) and then determines 1206 whether or not a grant transmitted with the current set of base stations (e.g., the strongest base station) at that aggregation level will be successfully decoded at the UE with a probability that meets Thprob(e.g., whether ≥ Thprob).

[0139] In the event that Thprobis met, then the MAC scheduler uses 1008 the current set of base stations and the present aggregation level to transmit the grant to the UE, and the method of the flowchart 1200 ends.

[0140] In the event that Thprob is not met, then the MAC scheduler determines 1210 whether a next higher aggregation level to the present aggregation level exists (e.g., aggregation level 2). If so, the MAC scheduler selects 1212 this next higher aggregation level and returns to determine 1206 whether or not a grant transmitted with the current set of base stations at that aggregation level will be successfully decoded at the UE with a probability that meets Thprob.

[0141] As before, in the event that Thprobis met, then the MAC scheduler uses 1208 the current set of base stations and the present aggregation level to transmit the grant to the UE, and the method of the flowchart 1200 ends. If not, the MAC scheduler proceeds to check for any next higher aggregation level to the present level and, if found, calculates the associated probability that a grant transmitted with the current set of base stations at that aggregation level will be successfully decoded by the UE and determines whether it meets Thprob, as previously described.

[0142] This action may be further repeated (additional aggregation levels may be checked) until either a workable aggregation level for the present base station set is24 P60803WO14882-1915-6730\1found (thereby ending the method of the flowchart 1200) or until all available aggregation levels have been tested with the present base station set.

[0143] In the event that the result of these repetitions is that the MAC scheduler determines that no available aggregation level is workable with respect to the present set of base stations, the MAC scheduler determines 1214 whether or not any additional base stations of the cluster are not yet part of the set of base stations being tested. If not, the MAC scheduler concludes 1218 that the grant will not be transmitted (at least in this TTI).

[0144] If there are additional base stations of the cluster that are not yet part of the set of base stations being tested, the MAC scheduler adds 1216 the next strongest base station for the UE that is not yet part of the set of base stations to the set of base stations. Then, the MAC scheduler again starts 1204 from the lowest aggregation level and moves up through the available aggregation levels checking for a workable aggregation level with the set of base stations, as previously described.

[0145] This action may be further repeated (additional base stations may be added to the set of base stations being checked against the available aggregation levels) until either a workable aggregation level / base station set combination is found (thereby ending the method of the flowchart 1200) or until there are no more base stations available for addition to the base station set.

[0146] It is noted that the method of the flowchart 1200 is applicable / useable regardless of beamforming (it is applicable in all frequency bands). In some embodiments, the network has the option to limit the maximum aggregation level (e.g., as in the case of 3GPP NR Rel-17 where valid aggregation levels may be limited to 1, 2, 4, 8, and 16).

[0147] FIG. 13A illustrates a first graph 1300 of individual transmission success probabilities from each of four base stations of a MAC entity, according to embodiments discussed herein. As illustrated in FIG. 13A, a first transmission success probability 1302 ("P1") applies with respect to a first base station 1304, a second transmission success probability 1306 ("P2") applies with respect to a second base station 1308, a third transmission success probability 1310 ("P3") applies with respect to a third base station 1312, and a fourth transmission success probability 1314 applies with respect to a fourth base station 1316. As illustrated, none of the first transmission success probability 1302, the second transmission success probability 1306, the third transmission success25 P60803WO14882-1915-6730\1probability 1310, and the fourth transmission success probability 1314 is individually sufficient to reach a configured Thprob1318.

[0148] Note that it is assumed that the first transmission success probability 1302, the second transmission success probability 1306, the third transmission success probability 1310, and the fourth transmission success probability 1314 have all been calculated with respect to a same (single) aggregation level for transmitting the PDCCH. In cases where there is more than one available aggregation level for transmitting the PDCCH, another set of calculated transmission success probabilities could be calculated for each of the first base station 1304, the second base station 1308, the third base station 1312, and the fourth base station 1316.

[0149] FIG. 13B illustrates a second graph 1320 of transmission success probabilities of various combinations of base stations of a MAC entity. FIG. 13B assumes the case of the UE, the MAC entity (including the base stations 1304, 1308, 1312, and 1316 along with their corresponding transmission success probabilities 1302, 1306, 1310, and 1314), and the Thprob1318 as were described in relation to FIG. 13A.

[0150] The case corresponding to the second graph 1320 of FIG. 13B also assumes that the same aggregation level discussed in relation to FIG. 13A is the only available aggregation level.

[0151] Per the method of the flowchart 1200, the MAC scheduler will repeatedly add base stations to a base station set until a calculated probability that a grant transmitted with the current set of base stations at that aggregation level will be successfully decoded by the UE (in the case of FIG. 11B, only the one aggregation level is available).

[0152] Under these circumstances, the MAC scheduler places the strongest base station (e.g., the third base station 1312, see FIG. 13A) into the set of base stations. The MAC scheduler then generates a first transmission success probability 1322 for the set of base stations. The first transmission success probability 1322 is equal to the third transmission success probability 1310 of the third base station 1312 that is currently alone in the set of base stations, as illustrated.

[0153] By comparing the first transmission success probability 1322 to Thprob1318, the MAC scheduler determines that the set of base stations cannot transmit a grant according to the present aggregation level such that the Thprob 1318 is met.

[0154] As there are no additional aggregation levels to check, the MAC scheduler proceeds to place the next strongest base station (e.g., the first base station 1304, see26 P60803WO14882-1915-6730\1FIG. 13A) into the set of base stations. The MAC scheduler then generates a second transmission success probability 1324 for the set of base stations. The second transmission success probability 1324 is calculated as a combination of the third transmission success probability 1310 and the first transmission success probability 1302 of the third base station 1312 and the first base station 1304 that are each in the set of base stations. Note that due to the physical placement / arrangement of each of the third base station 1312 and the first base station 1304 relative to the UE, the third transmission success probability 1310 of the third base station 1312 and the first transmission success probability 1302 of the first base station 1304 may not combine linearly (as can be seen by comparing the third transmission success probability 1310 of the third base station 1312 and the first transmission success probability 1302 of the first base station 1304 to the second transmission success probability 1324).

[0155] By comparing the second transmission success probability 1324 to Thprob1318, the MAC scheduler determines that the set of base stations cannot transmit a grant according to the present aggregation level such that Thprob1318 is met.

[0156] Again, as there are no additional aggregation levels to check with the set of base stations as currently constituted, the MAC scheduler proceeds to place the next strongest base station (e.g., the fourth base station 1316, see FIG. 13A) into the set of base stations. The MAC scheduler then generates a third transmission success probability 1326 for the set of base stations. The third transmission success probability 1326 is calculated as a combination of the third transmission success probability 1310, the first transmission success probability 1302, and the fourth transmission success probability 1314 of the third base station 1312, the first base station 1304, and the fourth base station 1316 that are each in the set of base stations. Again, due to the physical placement / arrangement of each of the base stations, the combination may not be linear.

[0157] By comparing the third transmission success probability 1326 to Thprob1318, the MAC scheduler determines that the set of base stations can transmit a grant according to the present aggregation level such that Thprob1318 is met. The method then ends, and the MAC scheduler proceeds to schedule the grant for transmission at the present aggregation level by (jointly) each of the third base station 1312, the first base station 1304, and the fourth base station 1316.

[0158] Note that FIG. 13B further illustrates a fourth transmission success probability 1328 representing the likelihood a grant will be successfully decoded when it is27 P60803WO14882-1915-6730\1transmitted using all base stations of the MAC entity, consistent with principles discussed herein. However, note that in the applied case just described, the method of the flowchart 1200 does not actually reach this calculation prior to ending.

[0159] In the context of the MAC entities described herein, various aspects with respect to the allocation of particular time-frequency resources for grants may be contemplated. In some generalized cases, it may be that base stations in the MAC operate according to different carrier frequencies, bandwidths, and / or numerologies.

[0160] Within such contexts, there are multiple options for allocating time-frequency resources for grants. In a first such option, each grant-transmitting base station (e.g., as decided per one of the methods discussed herein) sends a copy of the grant in its own band. The UE may monitor one or multiple of these base stations for the grants.

[0161] In a second such option, a common resource pool (e.g., using a same numerology at all base stations in the MAC entity) is used by the base stations to transmit grants. Grant-transmitting base stations accordingly are understood to use the same set of time-frequency resources for this resource pool in which they transmit grants.

[0162] Within the context of the first option (where each grant-transmitting base station sends a copy of the grant in its own band), there are various alternatives available for PDCCH reception at the UE.

[0163] In a first such alternative, combining at the baseband level may be used. In such cases, I / Q samples that correspond to the same PDCCH constellation point are added in baseband before demodulation. In this alternative, the UE attempts to find and process all the PDCCH copies within each search space to in order to detect and decode DCIs.

[0164] In a second such alternative, incremental redundancy combining may be used. In such cases, various redundancy versions are used for PDCCHs transmitted from different base stations. The UE exploits this information in baseband to improve its PDCCH decoding probability.

[0165] In a third such alternative, it may be that no combining may be used. In such cases, the UE may consecutively attempt decoding of PDCCHs from base station to base station and terminates the search for UE-specific grants as soon as it decodes one PDCCH successfully.28 P60803WO14882-1915-6730\1

[0166] Within the context of the first option (where each grant-transmitting base station sends a copy of the grant in its own band), there are various alternatives available for PDCCH searching mechanisms used at the UE. Such options may be directed toward search acceleration in order to reduce the PDCCH search time and / or to improve a power efficiency of the UE.

[0167] In a first such alternative, during CORESET configuration, the network configures the UE with a threshold for, for example, one or more of power spectral density, aggregate received power, and / or SNR for each applicable CORESET that is used for receiving PDCCHs from the base stations. Then, when the UE receives one of these CORESETs, it estimates the relevant quantity as represented in the CORESET. If the estimated value is lower than the configured threshold for that value for the CORESET, the UE skips PDCCH search in (this instance of) the CORESET altogether.

[0168] In a second such alternative, radio resources (e.g., control channel elements (CCEs)) within each CORESET are indexed in a unified manner across the CORESETs (e.g., starting from CCEs). The network then allocates the PDCCHs dedicated to a specific UE at resources with the same index in each of the CORESETs configured for the UE. The UE may then perform general PDCCH searching within one of the CORESETs to identify a PDCCH in that CORESET. Then, for subsequent (instances of) CORESETs, it performs blind decoding only for potential PDCCH allocations at / according to the same index of the PDCCH found in the first CORESET.

[0169] A scenario for time-frequency resource assignment for grants in the context of the second option (where a common resource pool is used by the base stations to transmit grants) is now discussed.

[0170] In this scenario, the grant in the common resource pool specifies shared channel allocations for all base stations (even though those base stations may have different bandwidths, carrier frequencies, numerologies, etc.). It is noted that, with respect to cases where power or log-likelihood ratio (LLR) combining for hybrid automatic repeat request (HARQ) is used, it is not required for base stations that are combined to have the same radio frequency properties (such as carrier frequency, bandwidth, and / or beamforming properties, etc.).

[0171] FIG. 14 illustrates a diagram 1400 of various bandwidths within time-frequency resources used by various base stations of a wireless communication system, according to embodiments discussed herein. The diagram 1400 shows that a first base station 140229 P60803WO14882-1915-6730\1operates within a first bandwidth 1404, a second base station 1406 and a third base station 1408 each operate within a second bandwidth 1410, that a fourth base station 1412 operates within a third bandwidth 1414, and that a common grant pool 1416 used by all of these base stations exists in a fourth bandwidth 1418.

[0172] Each of the first base station 1402, the second base station 1406, the third base station 1408, and / or the fourth base station 1412 may accordingly provide one or more grants 1420 in the common grant pool 1416 (within the fourth bandwidth 1418). These one or more grants 1420 may each schedule resources in one or more of the first bandwidth 1404, the second bandwidth 1410, and / or the third bandwidth 1414, as illustrated.

[0173] FIG. 15 illustrates a cell-free MAC entity 1500 that uses a first base station 1502, a second base station 1504, a third base station 1506, and a fourth base station 1508 to communicate with a UE 1510, according to embodiments discussed herein.

[0174] Various options for types of supported grants within a cell-free MAC entity are now discussed. In some embodiments, one DL grant can correspond to one of various possible multiple input multiple output (MIMO) modes of operation with different base stations and / or groups of base stations. In some examples, a DL grant may correspond to a case where one stream per base station is used with respect to some base stations. FIG. 15 illustrates this case with respect to communications between the third base station 1506 and the UE 1510.

[0175] In some examples, a DL grant may correspond to a case where a same stream is sent from multiple base stations (each of the base stations in this group sends a stream identical to the other base stations in this group). FIG. 15 illustrates this case with respect to communications between the fourth base station 1508 and the UE 1510 (e.g., assuming that the fourth base station 1508 is configured to send the same stream as the stream of the third base station 1506 as previously discussed).

[0176] In another example, the DL grant can correspond to a case where space-time orthogonal block coded (STOBCed) streams from multiple base stations are used (e.g., two base stations transmitting using an Alamouti scheme). FIG. 15 illustrates this case with respect to communications between the first base station 1502 and the second base station 1504 and the UE 1510.30 P60803WO14882-1915-6730\1

[0177] It is contemplated that combinations of these examples may be used within a MAC entity (e.g., as illustrated). Further, these mechanisms may be employed for both beamforming and non-beamforming cases.

[0178] FIG. 16 illustrates a method 1600 of a MAC scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a UE, according to embodiments herein. The illustrated method 1600 includes determining 1602 that a base station set comprising one or more base stations of the plurality of base stations of the MAC entity cannot transmit a PDCCH using a first aggregation level to meet a first minimum power level corresponding to the first aggregation level for the UE to successfully decode the PDCCH. The method 1600 further includes adding 1604, to the base station set, an additional base station from the plurality of base stations of the MAC entity. The method 1600 further includes determining 1606, after adding the additional base station to the base station set, that the base station set can transmit the PDCCH at the first aggregation level to meet the first minimum power level corresponding to the first aggregation level for the UE to successfully decode the PDCCH. The method 1600 further includes transmitting 1608 the PDCCH to the UE using the base station set at the first aggregation level.

[0179] In some embodiments, the method 1600 further comprises determining, prior to adding the additional base station to the base station set, that the base station set cannot transmit the PDCCH using a second aggregation level to meet a second minimum power level corresponding to the second aggregation level for the UE to successfully decode the PDCCH.

[0180] In some embodiments of the method 1600, the determining that the base station set cannot transmit the PDCCH at the first minimum power level corresponding to the first aggregation level comprises generating a calculated power level for the PDCCH based on one or more individual power levels corresponding to the one or more base stations, and determining that the calculated power level does not meet the first minimum power level corresponding to the first aggregation level.

[0181] In some embodiments of the method 1600, the determining that the base station set can transmit the PDCCH at the first minimum power level corresponding to the first aggregation level comprises generating a calculated power level for the PDCCH based on one or more individual power levels corresponding to the one or more base stations,31 P60803WO14882-1915-6730\1and determining that the calculated power level meets the first minimum power level corresponding to the first aggregation level.

[0182] In some embodiments of the method 1600, the first aggregation level is a maximum possible aggregation level for the PDCCH from a set of one or more aggregation levels useable by the base station set. Some such embodiments further comprise determining the maximum possible aggregation level for the PDCCH based on a network configuration for the PDCCH. Some such embodiments further comprise determining the maximum possible aggregation level for the PDCCH based on an amount of available resources in a CORESET for the PDCCH.

[0183] In some embodiments of the method 1600, the first aggregation level is less than a maximum possible aggregation level for the PDCCH from a set of one or more aggregation levels useable by the base station set.

[0184] In some embodiments, the method 1600 further comprises determining the minimum power level corresponding to the first aggregation level for the UE by summing one or more of: a minimum signal-to-noise ratio power level for the UE to decode the PDCCH at the first aggregation level for the PDCCH, a noise power level, and a guard power level.

[0185] FIG. 17 illustrates a method 1700 of a MAC scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a UE, according to embodiments herein. The illustrated method 1700 includes determining 1702 that a base station set comprising one or more base stations of the plurality of base stations of the MAC entity cannot transmit a PDCCH with at least a minimum probability that the UE will successfully decode the PDCCH. The method 1700 further includes adding 1704, to the base station set, an additional base station from the plurality of base stations of the MAC entity. The method 1700 further includes determining 1706, after adding the additional base station to the base station set, that the base station set can transmit the PDCCH to the UE with at least the minimum probability. The method 1700 further includes transmitting 1708 the PDCCH to the UE using the base station set.

[0186] In some embodiments of the method 1700, the determining that the base station set cannot transmit the PDCCH with at least the minimum probability comprises generating a calculated probability that a UE will successfully decode the PDCCH based on one or more individual power levels corresponding to the one or more base stations, an estimated noise power level, and a maximum possible aggregation level for the32 P60803WO14882-1915-6730\1PDCCH, and determining that the calculated probability does not meet the minimum probability.

[0187] In some embodiments of the method 1700, the determining that the base station set can transmit the PDCCH with at least the minimum probability comprises generating a calculated probability that a UE will successfully decode the PDCCH based on one or more individual power levels corresponding to the one or more base stations, an estimated noise power level, and a maximum possible aggregation level for the PDCCH, and determining that the calculated probability does meets the minimum probability.

[0188] In some embodiments of the method 1700, the determining that the base station set cannot transmit the PDCCH with at least the minimum probability comprises determining that the base station set cannot transmit the PDCCH with at least the minimum probability when using a maximum possible aggregation level for the PDCCH. Some such embodiments further comprise determining the maximum possible aggregation level for the PDCCH based on a network configuration for the PDCCH. Some such embodiments further comprise determining the maximum possible aggregation level for the PDCCH based on an amount of available resources in a CORESET for the PDCCH.

[0189] In some embodiments of the method 1700, the determining that the base station set cannot transmit the PDCCH with at least the minimum probability comprises determining that the base station set cannot transmit the PDCCH with at least the minimum probability according to each of a plurality of possible aggregation levels for the PDCCH.

[0190] In some embodiments of the method 1700, the determining that the base station set can transmit the PDCCH at the minimum probability comprises determining that the base station set can transmit the PDCCH with at least the minimum probability according to a first aggregation level of a plurality of possible aggregation levels for the PDCCH. In some such embodiments, the first aggregation level is less than a maximum possible aggregation level for the PDCCH. In some such embodiments, the minimum probability is configured to the MAC scheduler by CCF controlling the cluster.

[0191] FIG. 18 illustrates a method 1800 of a UE that is served by a cluster of base stations, according to embodiments herein. The illustrated method 1800 includes receiving 1802 a PDCCH in a MAC entity comprising a plurality of base stations from the cluster of base stations, wherein the reception of the PDCCH in the MAC entity33 P60803WO14882-1915-6730\1comprises: receiving, from a first base station of the plurality of base stations of the MAC entity, in a first CORESET in a first band used by the first base station, a first copy of the PDCCH, receiving, from a second base station of the plurality of base stations of the MAC entity, in a second CORESET in a second band used by the second base station, a second copy of the PDCCH, and determining the PDCCH by combining the first copy of the PDCCH and the second copy of the PDCCH. The method 1800 further includes performing 1804 communications between the UE and the cluster according to a scheduling grant of the PDCCH.

[0192] In some embodiments, the method 1800 further comprises receiving, from the cluster, first configuration information configuring the first CORESET in the first band, and receiving, from the cluster, second configuration information configuring the second CORESET in the second band. In some such embodiments, the first configuration information comprises a power metric threshold for the first CORESET and some such embodiments further comprise estimating that the first CORESET meets the power metric threshold for the first CORESET, wherein the UE receives the first copy of the PDCCH in the first CORESET in response to the estimating that the first CORESET meets the power metric threshold for the first CORESET.

[0193] In some embodiments of the method 1800, the UE identifies a CCE index for a CCE of the first CORESET in which the first copy of the PDCCH is received, and applies the CCE index to the second CORESET to locate the second copy of the PDCCH in the second CORESET.

[0194] In some embodiments of the method 1800, the combining the first copy of the PDCCH and the second copy of the PDCCH comprises adding a first sample of the first PDCCH and a second sample of the second PDCCH that correspond to a same constellation point for the PDCCH.

[0195] In some embodiments of the method 1800, the first copy of the PDCCH comprises a first redundancy version of the PDCCH, the second copy of the PDCCH comprises a second redundancy version of the PDCCH, and the combining the first copy of the PDCCH and the second copy of the PDCCH comprises combining the first redundancy version of the PDCCH and the second redundancy version of the PDCCH.

[0196] In some embodiments of the method 1800, the scheduling grant indicates that a first data stream is to be received from the first base station. In some such embodiments,34 P60803WO14882-1915-6730\1the scheduling grant further indicates that the first data stream is to be received from the second base station.

[0197] In some embodiments of the method 1800, the scheduling grant indicates that a first data stream is a STOBCed stream to be received from the first base station and the second base station.

[0198] FIG. 19 illustrates a method 1900 of a UE that is served by a cluster of base stations, according to embodiments herein. The illustrated method 1900 includes receiving 1902 a PDCCH in a MAC entity comprising a plurality of base stations from the cluster of base stations, wherein the reception of the PDCCH in the MAC entity comprises: failing the PDCCH in a first CORESET in a first band used by a first base station of the plurality of base stations of the MAC entity, and decoding the PDCCH in a second CORESET in a second band used by a second base station of the plurality of base stations of the MAC entity based on the failure to decode the PDCCH in the first CORESET. The method 1900 further includes performing 1904 communications between the UE and the cluster according to a scheduling grant of the PDCCH.

[0199] In some embodiments, the method 1900 further comprises receiving, from the cluster, first configuration information configuring the first CORESET in the first band, and receiving, from the cluster, second configuration information configuring the second CORESET in the second band. In some such embodiments, the second configuration information comprises a power metric threshold for the second CORESET, and some such embodiments further comprise estimating that the second CORESET meets the power metric threshold for the second CORESET, wherein the UE decodes PDCCH in the second CORESET in response to the estimating that the second CORESET meets the power metric threshold for the second CORESET.

[0200] In some embodiments of the method 1900, the scheduling grant indicates that a first data stream is to be received from the first base station. In some such embodiments, the scheduling grant further indicates that the first data stream is to be received from the second base station.

[0201] In some embodiments of the method 1900, the scheduling grant indicates that a first data stream is a STOBCed stream to be received from the first base station and the second base station.

[0202] FIG. 20 illustrates a method 2000 of a cluster of base stations serving a UE, according to embodiments herein. The illustrated method 2000 includes formulating35 P60803WO14882-1915-6730\12002 a PDCCH comprising a scheduling grant for communications between the cluster and the UE. The method 2000 further includes sending 2004 the PDCCH in a MAC entity comprising a plurality of base stations from the cluster of base stations, wherein the sending of the PDCCH in the MAC entity comprises: sending, to the UE, by a first base station of the plurality of base stations of the MAC entity, in a first CORESET in a first band used by the first base station, a first copy of the PDCCH, and sending, to the UE, by a second base station of the plurality of base stations of the MAC entity, in a second CORESET in a second band used by the second base station, a second copy of the PDCCH. The method 2000 further includes performing 2006 the communications between the cluster and the UE according to the scheduling grant of the PDCCH.

[0203] In some embodiments, the method 2000 further comprises sending, to the UE, first configuration information configuring the first CORESET in the first band, and sending, to the UE, second configuration information configuring the second CORESET in the second band. In some such embodiments, the first configuration information comprises a power metric threshold for the first CORESET.

[0204] In some embodiments of the method 2000, the first copy of the PDCCH is sent in a first CCE of the first CORESET having a first CCE index, and the second copy of the PDCCH is sent in a second CCE of the second CORESET having the first CCE index.

[0205] In some embodiments of the method 2000, the first copy of the PDCCH comprises a first redundancy version of the PDCCH, and the second copy of the PDCCH comprises a second redundancy version of the PDCCH.

[0206] In some embodiments of the method 2000, the scheduling grant indicates that a first data stream is to be sent by the first base station. In some such embodiments, the scheduling grant further indicates that the first data stream is to be sent by the second base station.

[0207] In some embodiments of the method 2000, the scheduling grant indicates that a first data stream is a STOBCed stream to be sent across the first base station and the second base station.

[0208] FIG. 21 illustrates a method 2100 of a UE that is served by a cluster of base stations, according to embodiments herein. The illustrated method 2100 includes receiving 2102, from the cluster, first configuration information indicating a maximum number of PDCCHs that may be sent in a MAC entity comprising a plurality of base36 P60803WO14882-1915-6730\1stations from the cluster of base stations per TTI. The method 2100 further includes receiving 2104, from the cluster, in the first MAC entity, in a CORESET used by the plurality of base stations of the MAC entity, one or more PDCCHs in a TTI, the one or more PDCCHs comprising one or more scheduling grants for communications between the cluster and the UE, wherein a number of the one or more PDCCHs is within the maximum number of PDCCHs that may be sent in the MAC entity per TTI. The method 2100 further includes performing 2106 the communications between the cluster and the UE according to the scheduling grants of the one or more PDCCHs.

[0209] In some embodiments of the method 2100, a first PDCCH of the one or more PDCCHs is received at the UE in the TTI from a first base station of the plurality of base stations of the MAC entity, and a second PDCCH of the one or more PDCCHs is received at the UE in the TTI from a second base station of the plurality of base stations of the MAC entity.

[0210] In some embodiments, the method 2100 further comprises receiving, from the cluster, second configuration information configuring the CORESET for use by the plurality of base stations of the MAC entity.

[0211] In some embodiments of the method 2100, the first configuration information is received in RRC signaling.

[0212] In some embodiments of the method 2100, the first configuration information is received in a MAC CE.

[0213] In some embodiments, the method 2100 further comprises receiving, from the cluster, a message indicating the number of the one or more PDCCHs.

[0214] In some embodiments of the method 2100, a first scheduling grant of the one or more scheduling grants indicates that a first data stream is to be received from a first base station of the plurality of base stations of the MAC entity. In some such embodiments, the scheduling grant further indicates that the first data stream is to be received from a second base station of the plurality of base stations of the MAC entity.

[0215] In some embodiments of the method 2100, the scheduling grant indicates that a first data stream is a STOBCed stream to be received from a first base station of the plurality of base stations of the MAC entity and a second base station of the plurality of base stations of the MAC entity.37 P60803WO14882-1915-6730\1

[0216] FIG. 22 illustrates a method 2200 of a cluster of base stations serving a UE, according to embodiments herein. The illustrated method 2200 includes sending 2202, method 2200, to the UE, first configuration information indicating a maximum number of PDCCHs that may be sent in a MAC entity comprising a plurality of base stations from the cluster of base stations per TTI. The method 2200 further includes formulating 2204, one or more PDCCHs comprising one or more scheduling grants that schedule communications between the cluster and the UE, wherein a number of the one or more PDCCHs is within the maximum number of PDCCHs that may be sent in the MAC entity per TTI. The method 2200 further includes sending 2206, to the UE, in the first MAC entity, in a CORESET used by the plurality of base stations of the MAC entity, the one or more PDCCHs in a TTI. The method 2200 further includes performing 2208 the communications between the cluster and the UE according to the scheduling grants of the one or more PDCCHs.

[0217] In some embodiments of the method 2200, a first PDCCH of the one or more PDCCHs is sent to the UE in the TTI by a first base station of the plurality of base stations of the MAC entity, and a second PDCCH of the one or more PDCCHs is sent to the UE in the TTI by a second base station of the plurality of base stations of the MAC entity.

[0218] In some embodiments, the method 2200 further comprises sending, to the UE, second configuration information configuring the CORESET for use by the plurality of base stations of the MAC entity.

[0219] In some embodiments of the method 2200, the first configuration information is sent in RRC signaling.

[0220] In some embodiments of the method 2200, the first configuration information is sent in a MAC CE.

[0221] In some embodiments, the method 2200 further comprises sending, to the UE, a message indicating the number of the one or more PDCCHs.

[0222] In some embodiments of the method 2200, a first scheduling grant of the one or more scheduling grants indicates that a first data stream is to be sent by a first base station of the plurality of base stations of the MAC entity. In some such embodiments, the scheduling grant further indicates that the first data stream is to be sent by a second base station of the plurality of base stations of the MAC entity.38 P60803WO14882-1915-6730\1

[0223] In some embodiments of the method 2200, the scheduling grant indicates that a first data stream is a STOBCed stream to be sent across a first base station of the plurality of base stations of the MAC entity and a second base station of the plurality of base stations of the MAC entity.

[0224] FIG. 23 illustrates an example architecture of a wireless communication system 2300, according to embodiments disclosed herein. The following description is provided for an example wireless communication system 2300 that operates in conjunction with the LTE system standards and / or 5G or NR system standards as provided by 3GPP technical specifications.

[0225] As shown by FIG. 23, the wireless communication system 2300 includes UE 2302 and UE 2304 (although any number of UEs may be used). In this example, the UE 2302 and the UE 2304 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.

[0226] The UE 2302 and UE 2304 may be configured to communicatively couple with a RAN 2306. In embodiments, the RAN 2306 may be NG-RAN, E-UTRAN, etc. The UE 2302 and UE 2304 utilize connections (or channels) (shown as connection 2308 and connection 2310, respectively) with the RAN 2306, each of which comprises a physical communications interface. The RAN 2306 can include one or more base stations (such as base station 2312 and base station 2314) that enable the connection 2308 and connection 2310.

[0227] In this example, the connection 2308 and connection 2310 are air interfaces to enable such communicative coupling, and may be consistent with RAT(s) used by the RAN 2306, such as, for example, an LTE and / or NR.

[0228] In some embodiments, the UE 2302 and UE 2304 may also directly exchange communication data via a sidelink interface 2316. The UE 2304 is shown to be configured to access an access point (shown as AP 2318) via connection 2320. By way of example, the connection 2320 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP 2318 may comprise a Wi-Fi®router. In this example, the AP 2318 may be connected to another network (for example, the Internet) without going through a CN 2324.

[0229] In embodiments, the UE 2302 and UE 2304 can be configured to communicate using orthogonal frequency division multiplexing (OFDM) communication signals with39 P60803WO14882-1915-6730\1each other or with the base station 2312 and / or the base station 2314 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.

[0230] In some embodiments, all or parts of the base station 2312 or base station 2314 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 2312 or base station 2314 may be configured to communicate with one another via interface 2322. In embodiments where the wireless communication system 2300 is an LTE system (e.g., when the CN 2324 is an EPC), the interface 2322 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 2300 is an NR system (e.g., when CN 2324 is a 5GC), the interface 2322 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 2312 (e.g., a gNB) connecting to 5GC and an eNB, and / or between two eNBs connecting to 5GC (e.g., CN 2324).

[0231] The RAN 2306 is shown to be communicatively coupled to the CN 2324. The CN 2324 may comprise one or more network elements 2326, which are configured to offer various data and telecommunications services to customers / subscribers (e.g., users of UE 2302 and UE 2304) who are connected to the CN 2324 via the RAN 2306. The components of the CN 2324 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).

[0232] In embodiments, the CN 2324 may be an EPC, and the RAN 2306 may be connected with the CN 2324 via an S1 interface 2328. In embodiments, the S1 interface 2328 may be split into two parts, an S1 user plane (S1-U) interface, which carries traffic data between the base station 2312 or base station 2314 and a serving gateway (S-GW),40 P60803WO14882-1915-6730\1and the S1-MME interface, which is a signaling interface between the base station 2312 or base station 2314 and MMEs.

[0233] In embodiments, the CN 2324 may be a 5GC, and the RAN 2306 may be connected with the CN 2324 via an NG interface 2328. In embodiments, the NG interface 2328 may be split into two parts, an NG user plane (NG-U) interface, which carries traffic data between the base station 2312 or base station 2314 and a user plane function (UPF), and the S1 control plane (NG-C) interface, which is a signaling interface between the base station 2312 or base station 2314 and access and mobility management functions (AMFs).

[0234] Generally, an application server 2330 may be an element offering applications that use internet protocol (IP) bearer resources with the CN 2324 (e.g., packet switched data services). The application server 2330 can also be configured to support one or more communication services (e.g., VoIP sessions, group communication sessions, etc.) for the UE 2302 and UE 2304 via the CN 2324. The application server 2330 may communicate with the CN 2324 through an IP communications interface 2332.

[0235] FIG. 24 illustrates a system 2400 for performing signaling 2434 between a wireless device 2402 and a network device 2418, according to embodiments disclosed herein. The system 2400 may be a portion of a wireless communications system as herein described. The wireless device 2402 may be, for example, a UE of a wireless communication system. The network device 2418 may be, for example, a base station (e.g., an eNB or a gNB) of a wireless communication system.

[0236] The wireless device 2402 may include one or more processor(s) 2404. The processor(s) 2404 may execute instructions such that various operations of the wireless device 2402 are performed, as described herein. The processor(s) 2404 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 hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0237] The wireless device 2402 may include a memory 2406. The memory 2406 may be a non-transitory computer-readable storage medium that stores instructions 2408 (which may include, for example, the instructions being executed by the processor(s) 2404). The instructions 2408 may also be referred to as program code or a computer41 P60803WO14882-1915-6730\1program. The memory 2406 may also store data used by, and results computed by, the processor(s) 2404.

[0238] The wireless device 2402 may include one or more transceiver(s) 2410 that may include radio frequency (RF) transmitter circuitry and / or receiver circuitry that use the antenna(s) 2412 of the wireless device 2402 to facilitate signaling (e.g., the signaling 2434) to and / or from the wireless device 2402 with other devices (e.g., the network device 2418) according to corresponding RATs.

[0239] The wireless device 2402 may include one or more antenna(s) 2412 (e.g., one, two, four, or more). For embodiments with multiple antenna(s) 2412, the wireless device 2402 may leverage the spatial diversity of such multiple antenna(s) 2412 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 2402 may be accomplished according to precoding (or digital beamforming) that is applied at the wireless device 2402 that multiplexes the data streams across the antenna(s) 2412 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).

[0240] In certain embodiments having multiple antennas, the wireless device 2402 may implement analog beamforming techniques, whereby phases of the signals sent by the antenna(s) 2412 are relatively adjusted such that the (joint) transmission of the antenna(s) 2412 can be directed (this is sometimes referred to as beam steering).

[0241] The wireless device 2402 may include one or more interface(s) 2414. The interface(s) 2414 may be used to provide input to or output from the wireless device 2402. For example, a wireless device 2402 that is a UE may include interface(s) 2414 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)42 P60803WO14882-1915-6730\12410 / antenna(s) 2412 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).

[0242] The wireless device 2402 may include a resource allocation module 2416. The resource allocation module 2416 may be implemented via hardware, software, or combinations thereof. For example, the resource allocation module 2416 may be implemented as a processor, circuit, and / or instructions 2408 stored in the memory 2406 and executed by the processor(s) 2404. In some examples, the resource allocation module 2416 may be integrated within the processor(s) 2404 and / or the transceiver(s) 2410. For example, the resource allocation module 2416 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) 2404 or the transceiver(s) 2410.

[0243] The resource allocation module 2416 may be used for various aspects of the present disclosure, for example, aspects of FIG. 18, FIG. 19, and / or FIG. 21. The resource allocation module 2416 may configure the wireless device 2402 to, for example, perform CORESET / PDCCH searching as described herein and / or to receive configuration information for PDCCHs, as is described herein.

[0244] The network device 2418 may include one or more processor(s) 2420. The processor(s) 2420 may execute instructions such that various operations of the network device 2418 are performed, as described herein. The processor(s) 2420 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.

[0245] The network device 2418 may include a memory 2422. The memory 2422 may be a non-transitory computer-readable storage medium that stores instructions 2424 (which may include, for example, the instructions being executed by the processor(s) 2420). The instructions 2424 may also be referred to as program code or a computer program. The memory 2422 may also store data used by, and results computed by, the processor(s) 2420.

[0246] The network device 2418 may include one or more transceiver(s) 2426 that may include RF transmitter circuitry and / or receiver circuitry that use the antenna(s) 2428 of the network device 2418 to facilitate signaling (e.g., the signaling 2434) to and / or from43 P60803WO14882-1915-6730\1the network device 2418 with other devices (e.g., the wireless device 2402) according to corresponding RATs.

[0247] The network device 2418 may include one or more antenna(s) 2428 (e.g., one, two, four, or more). In embodiments having multiple antenna(s) 2428, the network device 2418 may perform MIMO, digital beamforming, analog beamforming, beam steering, etc., as has been described.

[0248] The network device 2418 may include one or more interface(s) 2430. The interface(s) 2430 may be used to provide input to or output from the network device 2418. For example, a network device 2418 that is a base station may include interface(s) 2430 made up of transmitters, receivers, and other circuitry (e.g., other than the transceiver(s) 2426 / antenna(s) 2428 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.

[0249] The network device 2418 may include a resource allocation module 2432. The resource allocation module 2432 may be implemented via hardware, software, or combinations thereof. For example, the resource allocation module 2432 may be implemented as a processor, circuit, and / or instructions 2424 stored in the memory 2422 and executed by the processor(s) 2420. In some examples, the resource allocation module 2432 may be integrated within the processor(s) 2420 and / or the transceiver(s) 2426. For example, the resource allocation module 2432 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) 2420 or the transceiver(s) 2426.

[0250] The resource allocation module 2432 may be used for various aspects of the present disclosure, for example, aspects of FIG. 16, FIG. 17, FIG. 20, and / or FIG. 22 . The resource allocation module 2432 may configure the network device 2418 to, for example, check whether a base station set can transmit a grant to meet a minimum power level for an aggregation level and / or with a sufficient probability using an aggregation level as described herein, to send PDCCHs / grants in one or more CORESETs as described herein, and / or to send configuration information for PDCCHs, as is described herein.44 P60803WO14882-1915-6730\1

[0251] Embodiments contemplated herein include an apparatus comprising means to perform one or more elements of any one or more of the method 1800, method 1900, and / or method 2100. This apparatus may be, for example, an apparatus of a UE (such as a wireless device 2402 that is a UE, as described herein).

[0252] 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 one or more of the method 1800, method 1900, and / or method 2100. This non-transitory computer-readable media may be, for example, a memory of a UE (such as a memory 2406 of a wireless device 2402 that is a UE, as described herein).

[0253] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry to perform one or more elements of any one or more of the method 1800, method 1900, and / or method 2100. This apparatus may be, for example, an apparatus of a UE (such as a wireless device 2402 that is a UE, as described herein).

[0254] 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 one or more of the method 1800, method 1900, and / or method 2100. This apparatus may be, for example, an apparatus of a UE (such as a wireless device 2402 that is a UE, as described herein).

[0255] Embodiments contemplated herein include a signal as described in or related to one or more elements of any one or more of the method 1800, method 1900, and / or method 2100.

[0256] Embodiments contemplated herein include a computer program or computer program product comprising instructions, wherein execution of the program by a processor is to cause the processor to carry out one or more elements of any one or more of the method 1800, method 1900, and / or method 2100. The processor may be a processor of a UE (such as a processor(s) 2404 of a wireless device 2402 that is a UE, as described herein). These instructions may be, for example, located in the processor and / or on a memory of the UE (such as a memory 2406 of a wireless device 2402 that is a UE, as described herein).45 P60803WO14882-1915-6730\1

[0257] Embodiments contemplated herein include an apparatus comprising means to perform one or more elements of any one or more of the method 1600, method 1700, method 2000, and / or method 2200. This apparatus may be, for example, an apparatus of a base station (such as a network device 2418 that is a base station, as described herein).

[0258] 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 one or more of the method 1600, method 1700, method 2000, and / or method 2200. This non-transitory computer-readable media may be, for example, a memory of a base station (such as a memory 2422 of a network device 2418 that is a base station, as described herein).

[0259] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry to perform one or more elements of any one or more of the method 1600, method 1700, method 2000, and / or method 2200. This apparatus may be, for example, an apparatus of a base station (such as a network device 2418 that is a base station, as described herein).

[0260] 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 one or more of the method 1600, method 1700, method 2000, and / or method 2200. This apparatus may be, for example, an apparatus of a base station (such as a network device 2418 that is a base station, as described herein).

[0261] Embodiments contemplated herein include a signal as described in or related to one or more elements of any one or more of the method 1600, method 1700, method 2000, and / or method 2200.

[0262] 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 one or more of the method 1600, method 1700, method 2000, and / or method 2200. The processor may be a processor of a base station (such as a processor(s) 2420 of a network device 2418 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 2422 of a network device 2418 that is a base station, as described herein).46 P60803WO14882-1915-6730\1

[0263] 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.

[0264] 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.

[0265] 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.

[0266] 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.

[0267] It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or47 P60803WO14882-1915-6730\1exceeding 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.

[0268] 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 the description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.48 P60803WO14882-1915-6730\1

Claims

CLAIMS 1. A method of a medium access control (MAC) scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a user equipment (UE), comprising: determining that a base station set comprising one or more base stations of the plurality of base stations of the MAC entity cannot transmit a physical downlink control channel (PDCCH) using a first aggregation level to meet a first minimum power level corresponding to the first aggregation level for the UE to successfully decode the PDCCH; adding, to the base station set, an additional base station from the plurality of base stations of the MAC entity; determining, after adding the additional base station to the base station set, that the base station set can transmit the PDCCH at the first aggregation level to meet the first minimum power level corresponding to the first aggregation level for the UE to successfully decode the PDCCH; and transmitting the PDCCH to the UE using the base station set at the first aggregation level.

2. The method of claim 1, further comprising determining, prior to adding the additional base station to the base station set, that the base station set cannot transmit the PDCCH using a second aggregation level to meet a second minimum power level corresponding to the second aggregation level for the UE to successfully decode the PDCCH.

3. The method of claim 1, wherein the determining that the base station set cannot transmit the PDCCH at the first minimum power level corresponding to the first aggregation level comprises: generating a calculated power level for the PDCCH based on one or more individual power levels corresponding to the one or more base stations; and determining that the calculated power level does not meet the first minimum power level corresponding to the first aggregation level.

4. The method of claim 1, wherein the determining that the base station set can transmit the PDCCH at the first minimum power level corresponding to the first aggregation level comprises:49 P60803WO14882-1915-6730\1generating a calculated power level for the PDCCH based on one or more individual power levels corresponding to the one or more base stations; and determining that the calculated power level meets the first minimum power level corresponding to the first aggregation level.

5. The method of claim 1, wherein the first aggregation level is a maximum possible aggregation level for the PDCCH from a set of one or more aggregation levels useable by the base station set.

6. The method of claim 5, further comprising determining the maximum possible aggregation level for the PDCCH based on a network configuration for the PDCCH.

7. The method of claim 5, further comprising determining the maximum possible aggregation level for the PDCCH based on an amount of available resources in a control resource set (CORESET) for the PDCCH.

8. The method of claim 1, wherein the first aggregation level is less than a maximum possible aggregation level for the PDCCH from a set of one or more aggregation levels useable by the base station set.

9. The method of claim 1, further comprising determining the minimum power level corresponding to the first aggregation level for the UE by summing one or more of: a minimum signal-to-noise ratio power level for the UE to decode the PDCCH at the first aggregation level for the PDCCH; a noise power level; and a guard power level.

10. A method of a medium access control (MAC) scheduler for a MAC entity comprising a plurality of base stations of a cluster of base stations serving a user equipment (UE), comprising: determining that a base station set comprising one or more base stations of the plurality of base stations of the MAC entity cannot transmit a physical downlink control channel (PDCCH) with at least a minimum probability that the UE will successfully decode the PDCCH; adding, to the base station set, an additional base station from the plurality of base stations of the MAC entity;50 P60803WO14882-1915-6730\1determining, after adding the additional base station to the base station set, that the base station set can transmit the PDCCH to the UE with at least the minimum probability; and transmitting the PDCCH to the UE using the base station set.

11. The method of claim 10, wherein the determining that the base station set cannot transmit the PDCCH with at least the minimum probability comprises: generating a calculated probability that a user equipment (UE) will successfully decode the PDCCH based on one or more individual power levels corresponding to the one or more base stations, an estimated noise power level, and a maximum possible aggregation level for the PDCCH; and determining that the calculated probability does not meet the minimum probability.

12. The method of claim 10, wherein the determining that the base station set can transmit the PDCCH with at least the minimum probability comprises: generating a calculated probability that a user equipment (UE) will successfully decode the PDCCH based on one or more individual power levels corresponding to the one or more base stations, an estimated noise power level, and a maximum possible aggregation level for the PDCCH; and determining that the calculated probability does meets the minimum probability.

13. The method of claim 10, wherein the determining that the base station set cannot transmit the PDCCH with at least the minimum probability comprises determining that the base station set cannot transmit the PDCCH with at least the minimum probability when using a maximum possible aggregation level for the PDCCH.

14. The method of claim 13, further comprising determining the maximum possible aggregation level for the PDCCH based on a network configuration for the PDCCH.

15. The method of claim 13, further comprising determining the maximum possible aggregation level for the PDCCH based on an amount of available resources in a control resource set (CORESET) for the PDCCH.

16. The method of claim 10, wherein the determining that the base station set cannot transmit the PDCCH with at least the minimum probability comprises determining that51 P60803WO14882-1915-6730\1the base station set cannot transmit the PDCCH with at least the minimum probability according to each of a plurality of possible aggregation levels for the PDCCH.

17. The method of claim 10, wherein the determining that the base station set can transmit the PDCCH at the minimum probability comprises determining that the base station set can transmit the PDCCH with at least the minimum probability according to a first aggregation level of a plurality of possible aggregation levels for the PDCCH.

18. The method of claim 17, wherein the first aggregation level is less than a maximum possible aggregation level for the PDCCH.

19. The method of claim 17, wherein the minimum probability is configured to the MAC scheduler by cluster control function (CCF) controlling the cluster.

20. An apparatus comprising means to perform the method of any of claim 1 to claim 19.

21. 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 19.

22. An apparatus comprising logic, modules, or circuitry to perform the method of any of claim 1 to claim 19.52 P60803WO14882-1915-6730\1

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