Patent Publication Number: US-2023156479-A1

Title: Multilink uplink grant management method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 17/165,419, filed Feb. 2, 2021 which is hereby incorporated in its entirety by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to wireless communications systems and related networks, and more particularly to mechanisms for providing user equipment (UE) with uplink grant schedules of provider equipment attached thereto in response to loss of Physical Downlink Control Channel (PDCCH) coverage. 
     BACKGROUND 
     This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Operators of mobile systems, such as Universal Mobile Telecommunications Systems (UMTSs), Long Term Evolution (LTE), and 5th Generation New Radio (5G-NR) described and being developed by the Third Generation Partnership Project (3GPP), are increasingly relying on wireless macrocell radio access networks (RANs) such as traditional cellular base stations, eNodeBs and the like, along with wireless small cell or microcell RANs in order to deploy, for example, indoor voice and data services to enterprises and other customers. For both macrocell RANs and small/micro cell RANs, increasing demands for wireless throughput make access to additional wireless spectrum desirable. 
     Converged networks contemplate that user equipment (UE) utilizing network services (e.g., voice, streaming media, data upload/download etc.) may access any available/compatible network, such as a WiFi network (e.g., 802.11xx networks), UMTS network, 5G-NR network and so on, preferably in a manner delivering network services to UE in a seamless manner. Converged network operators may deploy networks comprising base stations, eNBs and the like operating in multiple spectral regions, such as high bands (24 GHz-40 GHz for 5G), mid bands (3.5 GHz-6 GHz and/or 1 GHz-2.6 GHz for 4G/LTE/5G), and low bands (&lt;1 GHz for 4G/LTE/5G).  100061  Converged networks may configured to use both licensed and unlicensed spectrum, such as unlicensed spectrum associated with citizens broadband radio service (CBRS), a 150 MZ band between 3.55 GHz and 3.70 GHz. Access is granted to Citizens Broadband Radio Service Devices (CBSDs) such as base stations, eNBs, user devices and the like operating according to a Generic Authorized Access (GAA) from 3.55 GHz to 3.65 GHz, with full access to 3.70 GHz expected in the future. GAA compliance may at times require a reduction in transmit power/range of CBSDs functioning as base stations / eNBs, such as when a GAA-define prioritized user requires this spectrum, which reductions may impact converged network operation in a manner causing non-seamless delivery of network services to UE. 
     SUMMARY 
     Various deficiencies in the prior art are addressed by systems, methods, and apparatus for enabling UE attached to a mobile network via a mid-band CBSD node to continue transmitting upload data to the mid-band CBSD node, even in the event of a loss of Physical Downlink Control Channels (PDCCH) coverage of the CBSD node resulting in a failure of the UE to receive uplink grant schedule updates. Various embodiments contemplate that the UE responsively attaches to a low-band node which, based on physical cell ID (PCI) of the CBSD node, retrieves updated uplink grant schedules from the CBSD node via a backhaul network and provides the uplink grant schedules to the UE. 
     One embodiment provides a method for allocating resources in a 5G network comprising Citizens Broadband Radio Service Device (CBSD) nodes and non-CBSD nodes configured for communicating with user equipment (UE), the method comprising: at a non-CBSD node, receiving a UE message reporting a physical cell ID (PCI) of a CBSD node to which the UE was attached prior to losing Physical Downlink Control Channels (PDCCH) coverage of the CBSD; at the non-CBSD node, transmitting toward a 5G core manager a message configured to cause a session management function (SMF) to resolve an internet protocol (IP) address associated with the reported PCI, and to forward to the non-CBSD node a message including the resolved IP address of the reported PCI; at the non-CB SD node, using the resolved IP address of the reported PCI to transmit toward a corresponding CBSD node a request for a new uplink grant schedule; and at the non-CBSD node, transmitting a received new UL grant schedule toward a source UE of the received UE message, the new UL grant schedule being configured to enable the source UE to transmit data toward the CBSD node via resource blocks allocations defined within the UL grant schedule. 
     Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention. 
         FIG.  1    depicts a block diagram of a system using a low power wide area (LPWA) network useful in illustrating the various embodiments; and 
         FIG.  2    depicts a flow diagram of a method enabling UE recovery from a loss of uplink (UL) grant schedule due to a CBSD transmission power reduction. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the sequence of operations as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes of various illustrated components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. 
     DETAILED DESCRIPTION 
     The following description and drawings merely illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its scope. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Additionally, the term, “or,” as used herein, refers to a non-exclusive or, unless otherwise indicated (e.g., “or else” or “or in the alternative”). Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. 
     The numerous innovative teachings of the present application will be described with particular reference to the presently preferred exemplary embodiments. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others. Those skilled in the art and informed by the teachings herein will realize that the invention is also applicable to various other technical areas or embodiments. 
     Various embodiments find particular utility within the context of converged networks configured to enable user equipment (UE) to access subscriber services via any of a plurality of available wireless networks as long as the QoS requirements are satisfied, such as a Wi-Fi network, 4G/LTE/5G network, unlicensed spectral regions and/or more than one network simultaneously. Unlicensed spectrum may comprise, illustratively, the Citizens Broadband Radio Service (CBRS) band at ˜3.5 GHz which is utilized by Citizens Broadband Radio Service Devices (CBSDs) registered with a Spectrum Access System (SAS) capable of adapting CBSD operation in accordance with government requirements, network congestion, network interference and the like. Such CB SD operational adaptations may include a reduction in transmit power/range of CBSDs functioning as base stations, gNBs, or eNBs, which may in turn mean that UEs attached thereto are unable to receive downlink schedule (DL-SCH) and/or uplink schedule (UL-SCH) information normally provided by the CBSD on a physical downlink control channel (PDCCH). Various embodiments are directed to specific mechanisms configured to mitigate this problem. 
       FIG.  1    depicts a block diagram of a network services architecture suitable for use in various embodiments. Specifically,  FIG.  1    depicts a converged network services architecture in which user equipment (UE) utilizing network services (e.g., voice, streaming media, data upload/download etc.) may access any available/compatible network as long as the quality of service (QoS) requirements of the relevant network services are satisfied, such as a WiFi network (e.g., 802.11xx networks) comprising many wireless access points (WAPs) or a heterogeneous mobile network (e.g., 3G, 4G/LTE, 5G) comprising many mid-band and low-band base stations, gNBs, or eNBs. 
     Referring to  FIG.  1   , user equipment (UE)  105 - 1  through  105 -M (collectively UE  105 ) are depicted as being configured for wirelessly communicating with a heterogeneous mobile network  101  (e.g., a LTE or 5G access network) formed as a plurality of base stations, gNBs, or eNBs comprising mid-band (e.g., 3.5 GHz) mobile network nodes  110 - 1  through  110 -N (collectively mid-band nodes  110 ) and low-band (e.g., under 1 GHz) mobile network nodes  115 - 1  through  115 -X (collectively low-band nodes  115 ). The heterogeneous mobile network  101  is connected to an evolved packet core (EPC)  120  configured to provide network services thereto, such as from/to external networks  130 . 
     In various embodiments, the UE  105  may also be configured for wirelessly communicating with WiFi Access Points (WAPs or APs)  160 , which are connected to a WiFi Controller  150  via, illustratively, an access network  170  such as provided by a telecommunications, cable television, and/or other network services provider. The WAPs  160  may comprise  802 . 11 xx wireless access points at homes, businesses, or other location that are configured to communicate with UE  105  and with an access network  170 . In various embodiments, a network services provider utilizes numerous such access points distributed over a “coverage footprint” to provide network services to mobile devices such as the UE  105  discussed herein. 
     The nodes  110 / 115  may comprise macrocells, small cells, microcells and the like such as eNodeBs (eNBs), cellular network base stations, 4G/5G repeaters, and similar types of provider equipment or logical radio nodes (e.g., gNBs) derived therefrom. The nodes  110 / 115  may include nodes that use licensed 3G/4G/LTE/5G spectrum, unlicensed spectrum such as citizens broadband radio service (CBRS) spectrum, or a combination of licensed and unlicensed spectrum. In the case of nodes  110  having Citizens Broadband Radio Service Device (CBSD) capability, allocations of CBRS spectrum are provided via a Spectrum Access System (SAS)  140 . 
     Each node  110 / 115  provides network services to UE via respective radio bearer (channels/resources) which are managed by various Radio Resource Management functions, such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Scheduling of UEs in both uplink and downlink and so on. The Radio Resource Management functions are configured to provide appropriate Quality of Service (QoS) levels to each UE using one or more radio bearers, to maximize throughput at the node  110 / 115  while maintaining “fairness” to the UE attached thereto, to monitor various performance metrics, to provide data to the core network or network management entities and the like. 
     For example each node  110 / 115  may include a Scheduler to implement uplink/downlink scheduling functions so as to allocate radio bearer resources to attached UE in accordance with appropriate QoS levels, which may comprise default QoS levels, QoS levels defined via Service Level Agreements (SLAs) of subscriber-associated with the UE, or some other mechanism. These radio bearer resources may be allocated in accordance with per-bearer QoS parameters such as QoS Class Identifiers (QCIs) which identify particular services or classes of services, Guaranteed Bit Rate (GBR) and/or Prioritized Bit Rate (PBR) which enable a determination as to specific radio bearers (e.g., specific UE) to accept, modify, or drop in response to a constrained resource condition, Allocation and Retention Policies (ARP) and the like. An Aggregate Maximum Bit Rate (AMBR) may be used to define a total bandwidth that may be utilized by a specific group of radio bearers (e.g., total bandwidth used supporting multiple network services associated with a one UE). 
     In various embodiments, node  110 / 115  scheduling decisions are dynamically signaled on a L1/L2 physical downlink control channel (PDCCH), which may periodically (e.g., at a 1 ms transmission time interval) provide downlink schedule (DL-SCH) and/or uplink schedule (UL-SCH) information. Additional PDCCH information provided to the UE may comprise physical resource allocation, Modulation and Coding scheme, New-Data indicator, Transport Block size, Redundancy version, HARQ Process ID and the like. To avoid frequent signaling (i.e., every 1 ms) semi-persistent scheduling may also be employed, such as to define UL/DL resources for a radio bearer used for a periodic type of transmission, or a transmission of a known size or duration. For example, resources defined in terms of subcarriers, slots, resource blocks (RBs) and the like may be allocated to specific UE such as in accordance with a resource block map provided to UE via an uplink (UL) grant schedule. 
     The UE  105  may comprise any type of wireless device configured for use in accordance with the various embodiments, such as user terminals (e.g., mobile phones, laptops, tablets and the like), fixed wireless access devices (e.g., set top boxes, digital video recorders, stationary computing devices and the like), Internet of Things (IoT) devices (e.g., sensors, monitoring devices, alarm system devices and the like), and/or other wireless devices. The UE  105  may include UE that use licensed 3G/4G/LTE/5G spectrum, unlicensed spectrum such as CBRS spectrum, or a combination of licensed and unlicensed spectrum. In the case of nodes  110  having CBSD capability, allocations of CBRS spectrum are provided via  140 . The various embodiments contemplate the UE are configured to communicate via at least one mobile network (MN) radio access technology (RAT) such as 3G, 4G/LTE, and 5G, and at least one WiFi access point technology such as 802.11xx (e.g., 802.11b, 802.11a, 802.11g, 802.11n, 802.11ac, 802.11ax and so on). 
     As depicted in  FIG.  1   , exemplary UE  105 - 1  comprises a mobile network mid-band transceiver  105 -MNMBT configured for communications with any of mid-band nodes  110 , a mobile network low-band transceiver  105 -MNLBT configured for communications with any of low-band nodes  115 , an optional WiFi transceiver  105 -WFT configured for communication with WAP  160 , and a connection manager  105 -CM configured to manage communications with the nodes  110 / 115  and APs  160 , and to facilitate handoffs and UE migration between different nodes  110 / 115 , between different APs  160 , and between mid-band nodes  110  and low-band nodes  115  such as described herein. The UE  105  also comprises various other components, modules, antennas, and the like (not shown). In various embodiments, one or more of the mid-band transceiver  105 -MNMBT low-band transceiver  105 -MNLBT, and WiFi transceiver  105 -WFT maybe combined to reduce the amount of circuitry necessary to implement these functions. 
     The connection manager  105 -CM may be configured to cause the UE to adapt the network or network node used by the UE to receive network services. For example, the connection manager  105 -CM may be configured to give priority to WiFi connectivity over mobile network connectivity when WiFi connectivity is available (e.g., to reduce mobile network congestion and the like). Similarly, the connection manager  105 -CM may be configured to give priority to mid-band nodes  110  using unlicensed spectrum (e.g., CBSD eNBs) over low-band nodes  115  using licensed spectrum (e.g., 600-900 MHz eNBs). 
     As depicted in  FIG.  1   , the EPC  120  comprises four network elements; namely, a Serving Gateway (SGW)  122 , a Mobility Management Entity (MME)  124 , a Packet Data Network (PDN) Gateway (PGW)  126 , and a Home Subscriber Server (HSS)  128 . Other network and management elements are typically included within and/or used to manage an evolved packet core, and related communications therewith as will be known to those skilled in the art. 
     The SGW  122  and PGW  126  handle user data or data plane (DP) functions; they transport internet protocol (IP) data traffic (i.e., incoming and outgoing packets) between the User Equipment (UE)  105  and the external networks  130 . The external networks  130  may comprise any external network, such as an IP Multimedia Core Network Subsystem (IMS).  100291  The SGW  122  is a point of interconnection between the radio-side (e.g., via a backhaul connection to the mobile network  101 ) and the EPC  120 . As its name indicates, this gateway serves the UE by routing the incoming and outgoing IP packets. The SGW  122  is the anchor point for intra-LTE mobility (i.e. in case of handover between eNodeBs  110 / 115 ) and between LTE, 5G, and other 3GPP accesses. The SGW  122  is logically connected to the PGW  126 . 
     The PGW  126  is the point of interconnect for routing packets between the EPC  120  and external packet data networks (e.g., Internet Protocol (IP) networks)  330 . The PGW also performs various functions such as IP address/IP prefix allocation, policy control and charging, and other functions. 
     The MME  124  and HSS  128  handle user signaling or control plane (CP) functions; they process signaling related to mobility and security for E-UTRAN  101  access. The MME  124  is responsible for the tracking and the paging of UE in idle-mode. It is the termination point of the Non-Access Stratum (NAS). The HSS  128  comprises a database that contains user-related and subscriber-related information, and provides support functions in mobility management, call and session setup, user authentication, access authorization, and other functions. It is noted that the SGW  122  may also be used to handle some control plane signaling in various configurations. 
     An EPC control plane signaling path CP may be used to provide information such as UE messages or signaling may be provided to the MME  124  or SGW  122 . The MME  124  may also interact with various other EPC nodes such as the HSS  128  and SGW  122  to determine information helpful in generating reports and/or providing other information for managing the various networks in implementing the embodiments described herein. 
     The EPC  120  may comprise a Session Management Function (SMF)  120 -SMF, a policy control function (PCF)  120 -PCF, and/or other functions in the EPC  120 , such as when implemented as a 5G core. 
     As depicted in  FIG.  1   , a Spectrum Access System (SAS)  140  communicates with the EPC  120  and is configured to control access to the CBRS frequency band for RANs and other CBSD devices such as nodes  110  and UEs  105 . Generally speaking, the SAS  140  is configured to ensure that the CBRS frequency band is allocated in accordance with the regulations promulgated by the relevant authorities. The SAS  140  may also communicate with the network manager  150  to perform various tasks in accordance with the embodiments. 
     As depicted in  FIG.  1   , a WiFi controller (WC)  150  communicates with a WiFi Access Point (WAP or AP)  160  via an access network  170 . For simplification of the discussion, only one WAP  160  is shown in  FIG.  1    as communicating with WiFi controller  150 , and only one UE  105  (i.e., UE  105 - 1 ) is shown in  FIG.  1    as communicating with that WAP  160 . The WiFi controller  150 , which may be implemented via a general purpose computer server, network operations center (NOC) equipment, or other provider equipment, is configured to perform various WiFi control functions associated with a large number of APs  160 , as well as an even larger number of UEs  105  configured to communicate with the various APs  160 . 
     Generally speaking, the WiFi controller (WC)  150  manages various operational aspects of the WAPs  160  and UE  105  connected thereto in accordance with WAP policies, subscriber/user profiles (e.g., such as defined in service level agreements) and the like. For example, each UE may be associated with a corresponding subscriber/user profile having defined therein guaranteed minimum levels of service, such as a minimum WAP download (DL) throughput, minimum uplink (UL) throughput, and/or other minimum QoS levels. 
     The system  100  of  FIG.  1    contemplates UE  105  associated with a network services provider capable of providing network services via either of the mid-band nodes  110  and low-band nodes  115 , or the optional WAPs  160 . 
     An exemplary heterogeneous mobile network  101  comprises mid-band nodes  110  including CBSD and non-CBSD eNBs or base stations, and low-band nodes  115  such as 600 MHz eNBs or base stations, wherein the various nodes  110 / 115  are deployed to provide overlapping coverage areas, though the 600 MHz coverage area of the low-band nodes  115  is generally larger than the 3.5 GHz coverage area of the mid-band nodes  110 . The nodes  110 / 115  are connected to the EPC  120  via back haul and/or other communications links. 
     Various elements or portions thereof depicted in  FIG.  1    and having functions described herein are implemented at least in part as computing devices having communications capabilities, including for example the UE  105 , nodes  110 / 115 , SAS  140 , WC  150 , WAP  160  and various portions of the EPC  120 . These elements or portions thereof have computing devices of various types, though generally a processor element (e.g., a central processing unit (CPU) or other suitable processor(s)), a memory (e.g., random access memory (RAM), read only memory (ROM), and the like), various communications interfaces (e.g., more interfaces enabling communications via different networks/RATs), input/output interfaces (e.g., GUI delivery mechanism, user input reception mechanism, web portal interacting with remote workstations and so on) and the like. 
     As such, the various functions depicted and described herein may be implemented at the elements or portions thereof as hardware or a combination of software and hardware, such as by using a general purpose computer, one or more application specific integrated circuits (ASIC), or any other hardware equivalents or combinations thereof. In various embodiments, computer instructions associated with a function of an element or portion thereof are loaded into a respective memory and executed by a respective processor to implement the respective functions as discussed herein. Thus various functions, elements and/or modules described herein, or portions thereof, may be implemented as a computer program product wherein computer instructions, when processed by a computing device, adapt the operation of the computing device such that the methods or techniques described herein are invoked or otherwise provided. Instructions for invoking the inventive methods may be stored in tangible and non-transitory computer readable medium such as fixed or removable media or memory, or stored within a memory within a computing device operating according to the instructions. 
       FIG.  2    depicts a flow diagram of a method enabling UE recovery from a loss of UL grant schedule due to a CBSD transmission power reduction. The method  200  of  FIG.  2    contemplates various functions performed by UE  105 , nodes  110 / 115 , SAS  140 , EPC  120 , and other functional entities as described above with respect to  FIG.  1   . 
     Generally speaking, the method  200  of  FIG.  2    is directed to managing UE  105  associated with a network services provider capable of providing network services via either of the mid-band nodes  110  or low-band nodes  115  of the heterogeneous network  101  discussed above with respect to  FIG.  1   . In an exemplary embodiment, the method  200  contemplates that UE  105  authenticated to a mid-band CBSD node  110  of the mobile network  101  and experiencing a loss of PDCCH coverage thereto is able to recover from the resulting loss of new UL grants by cooperating with a proximate low-band node  115 . 
     Specifically, as previously noted, proactive grants are used in dedicate uplink (UL) resources to UE in 5G standards. The eNB or base station determines the amount of resource blocks (RBs) and time of resource blocks usage for each UE in the network (e.g., such as defined in a resource block map communicated to UE via an UL grant schedule), and timing of UL grants can change anytime. This change is communicated with UE using a Physical Downlink Control Channel (PDCCH). In a regular 5G networks, the PDCCH coverage area is usually greater than the Physical Uplink Control Channel (PUCCH) coverage area. In CBRS networks, since transmission power of a CBSD can be decreased by the SAS at any time depending on interference, PDCCH coverage can be reduced at any time. This means that the PDCCH coverage can be smaller than PUCCH coverage area, which also means that the base station/eNB may not be able to pre-configure a UL grant schedule with the UE since the UL grant schedule is communicated to the UE via the PDCCH. 
     At step  210 , UE attaches to the mobile network  101  via a CBSD node  110  (e.g., UE  105  attached to a mid-band node  110  of a 4G/LTE or 5G mobile network). Referring to box  215 , the attachment comprises various known steps such as the UE being authenticated by the mobile network, and the UE being associated with a subscriber having a service level agreement (SLA) defining quality of service (QoS) and other metrics of network services to be provided to the subscriber UE. The international mobile subscriber identifier (IMSI) of the UE and other information is provided to the MME, along with the current tracking area of the UE, which is periodically updated as the UE location moves between different mid-band nodes  110  or sectors thereof, or different low-band nodes  115  or sectors thereof. Other functions are also contemplated during this attachment as is known. It is noted that the a CBSD node  110  is a mid-band mobile network node that has previously been registered with the SAS  140 , and which has been granted spectrum by the SAS  140  for use in communicating with UE  105  and for performing other functions as is known. In addition, the SAS  140  has defined a transmit power for use by the CBSD node  110 , which defines a transmission coverage area associated with the CBSD node  110 . 
     At step  220 , in response to a determination by the UE that the transmit coverage area of the CBSD node  110  no longer includes the UE (i.e., the PDCCH signal including new UL grants is no longer being received), the UE attaches to a low-band node  115  and transmits a message to the low-band node  115  to report the loss of PDCCH coverage and to identify the mid-band node  110  via, illustratively, its physical cell ID (PCI). It is noted that the UE does not detach itself from the mid-band node  110 . 
     At step  230 , the low-band node  115  receives the message from the UE and responsively transmits a back haul message to the EPC core  120  configured to cause a management entity therein to resolve an IP address associated with the PCI of the power-reduced CBSD node  110 . Specifically, in various embodiments this message is configured to cause a session management function (SMF) of a 5G core to resolve the IP address of the CBSD node associated with the PCI and forward that IP address to the low-band node  115 . 
     At step  240 , the low-band node  115  receives the resolved IP address of the power-reduced CBSD node  110  and responsively uses the resolved IP address to transmits a back haul message to the power-reduced CBSD node  110  requesting a new UL grant schedule, which new UL grant schedule is transmitted within a message carried by the back haul network from the power-reduced CBSD node  110  to the low-band node  115 . The new UL grant schedule include the identity of UE having UL grants defined therein via one or more of a Radio Network Temporary Identifier (RNTI), an International Mobile Subscriber Identifier (IMSI), an International Mobile Equipment Identity (IMEI), a Mobile Equipment Identifier (MEID), an Electronic Serial Number (ESN), or some other UE identification/identifier. 
     At step  250 , the low-band node  115  transmits the received new UL grant schedule to the UE reporting the PDCCH coverage loss, any UE attached to the low-band node  115  that recently reported a PDCCH coverage loss associated with the same PCI, and/or any UE attached to the low-band node  115  identified in the received new UL grant. 
     At step  260 , each relevant UE (i.e., UE having lost PDCCH coverage from the CBSD node  110 ) receiving the new UL grant schedule associated with the CBSD node  110  examines the new UL grant schedule and transmits data to the CBSD node  110  in accordance with its respective uplink slots or resource blocks as allocated to the UE via the UL grant schedule (e.g., such as defined in a resource block map communicated to UE via the UL grant). Specifically, each relevant UE flushes its uplink/output buffer via data transmission to the mid-band node (i.e., CBSD node  110 ) in accordance with respective UL grants, optionally and additionally via contemporaneous data transmission to the low-band node  115 . Further, each relevant UE then waits for its mid-band node PDCCH coverage to return (i.e., for a PDCCH signal including new UL grants to be received from the mid-band node). The UE wait time may be defined in accordance with a predetermined, default or programmable waiting period, a waiting period that ends when data transmission is deemed to be necessary (e.g., a need to transmit time-sensitive or priority data, a determination that an uplink/output buffer is above a threshold utilization level, etc.), and/or some other criteria. 
     At step  270 , each relevant UE having determined within its wait time that PDCCH coverage has returned (i.e., having received from the CBSD node  110  a PDCCH signal including new UL grants) may detach from the low-band node  115 , in which case the low-band node  115  may tear down the session created for the UE. 
     At step  280 , each relevant UE having determined within its wait time that PDCCH coverage has not returned, may detach from the CBSD node  110  and (1) attach to the mobile network via a new/available CBSD node  110 , (2) remain attached to the mobile network via the current low-band node, (3) attach to the mobile network via a new/available low-band node, or (4) attach to the mobile network via some other node (e.g., a base station, gNB, or eNB of a mobile virtual network operator (MVNO) partner or third party. 
     The above-described embodiments are primarily directed to the issue of a loss of UE inability to receive the UL grant schedule due to a reduction in CL coverage area/distance, such as due to a reduction in power of a CB SD node (in which case data for the UE within the relevant DL slots will also be lost). It is noted that PDSCH coverage area/distance is always shorter then PDCCH, and control coverage will be lost later once the UE loses data (PDSCH) coverage. In various embodiments, a low-band node (e.g., a 600 MHz gNB) may send grant schedule information to UE once the CBSD coverage is lost. 
     Various modifications may be made to the systems, methods, apparatus, mechanisms, techniques and portions thereof described herein with respect to the various figures, such modifications being contemplated as being within the scope of the invention. For example, while a specific order of steps or arrangement of functional elements is presented in the various embodiments described herein, various other orders/arrangements of steps or functional elements may be utilized within the context of the various embodiments. Further, while modifications to embodiments may be discussed individually, various embodiments may use multiple modifications contemporaneously or in sequence, compound modifications and the like. It will be appreciated that the term “or” as used herein refers to a non-exclusive “or,” unless otherwise indicated (e.g., use of “or else” or “or in the alternative”). 
     Although various embodiments which incorporate the teachings of the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. Thus, while the foregoing is directed to various embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.