Patent Description:
Statically allocated resources (e.g., allocated resources on a recurrent and/or periodic basis) can further compound the availability of the air interface resources. To illustrate, consider an air interface resource shared between two base stations with overlapping cell and/or coverage areas using time-division multiplexing (TDM) such that a first base station accesses the shared air interface resource over a first time period and a second base station accesses the shared air interface resource over a second time period. While the static allocation provides each base station with access to the shared air interface resource, the static allocation also reduces the availability of the resource to each base station. Inefficiencies in using the statically allocated air interface resource can occur, such as when the first base station serves few-to-no devices and does not use the shared air interface resource during portions of the first time period. Because the first base station does not use the shared air interface resource during part of the first time period, and the static allocation prevents the second base station from using the shared air interface resource during the first time period, the shared air interface resource remains unused during the first time period. Thus, to increase capacity and deliver reliable wireless connections, evolving communication systems look for new approaches to efficiently utilize the available resources and avoid waste.

<CIT> proposes a user equipment (UE) that may receive scheduling information for a transmission associated with a particular radio access technology (RAT) of a <NUM> RAT or a <NUM> RAT, wherein the scheduling information identifies a particular resource of one of a first set of resources for the <NUM> RAT or a second set of resources for the <NUM> RAT, wherein one or more resources of the first set of resources are guaranteed for the <NUM> RAT based at least in part on a reference <NUM> time division duplexing (TDD) configuration, and wherein the one or more resources of the first set of resources and the second set of resources do not overlap in a time domain; and transmit or receive the transmission using the particular resource.

<CIT> proposes a method in a communication node for commonly managing resources in a radio access network between different network access technologies, which communication node is comprised in a radio access network of a radio communications network. The communication node receives from a first local resource manager of a first network access technology, a first report of information regarding resources needed per service associated with the first network access technology, which service is associated with a first local service priority. The communication node then receives from a second local resource manager of a second network access technology, a second report of information regarding resources needed per service associated with the second network access technology. The service is associated with a second local service priority. The communication node ranks the service priority in the first report in relation to the service priority in the second report. The communication node generates an allocation scheme of resources, which allocation scheme allocates resources to at least one of the first or second local resource managers based on the ranking of the service priorities.

In a paper entitled "LTE-NR Co-existence" (Samsung, 3GPP DRAFT; R2-<NUM>), the authors discuss possible mechanisms and specification supports to achieve LTE-NR coexistence.

According to a first aspect of the present invention, there is provided a method as set out in claim <NUM>. According to a second aspect of the present invention, there is provided a method as set out in claim <NUM>. According to a third aspect of the present invention, there is provided a base station as set out in claim <NUM>. According to a fourth aspect of the present invention, there is provided a user equipment as set out in claim <NUM>. The details of one or more implementations of enhanced uplink spectrum sharing are set forth in the accompanying drawings and the following description. This summary is provided to introduce subject matter that is further described in the Detailed Description and Drawings. Accordingly, this summary should not be considered to describe essential features nor used to limit the scope of the claimed subject matter.

The details of one or more aspects of enhanced uplink spectrum sharing are described below. The use of the same reference numbers in different instances in the description and the figures indicate similar elements:.

Various technologies, such as television and radio broadcasts, cellular networks, satellite communications, wireless local area networks (WLAN), and so forth, transmit wireless communications over different portions of the radio frequency spectrum. To avoid contentions between the transmissions, a regulatory body, such as the Office of Communications (Ofcom), the Ministry of Industry and Information Technology (MIIT), the National Telecommunications and Information Administration (NTIA), and the Federal Communications Commission (FCC), among others, governs how a particular region allocates portions of the radio frequency spectrum to the various technologies. Thus, in aspects, each technology has access to a finite portion of the spectrum, based on the spectrum plan mandated by the regulatory body.

The availability of a frequency band and/or portion of radio spectrum becomes strained as an increasing number of devices attempt to use the corresponding technology. To illustrate, a first base station serving a single user equipment (UE) can direct most of the allocated spectrum to the single UE, while a second base station serving multiple UEs divides the available radio spectrum amongst the multiple UEs. Because the frequency band and/or portion of radio spectrum allocated to the cellular technology implemented by the base stations has a finite size, each base station can simultaneously support only a finite number of UEs. Thus, to increase capacity and deliver reliable wireless connections, it is desirable to increase the efficiency of how the corresponding resources of the technology are used and to reduce wasted resources.

At times, Radio Access Technologies (RATs) share radio spectrum, such as by sharing a common frequency band through frequency-division multiplexing (FDM), time-division multiplexing (TDM), and so forth. As one example, fourth generation (<NUM>) wireless networks dynamically share portions of the sub-<NUM> Gigahertz (GHz) radio spectrum with fifth generation (<NUM>) networks, using FDM, TDM, common air interface resource partitioning, and/or synchronized timebases. Alternatively, or additionally, a network operator of a radio access network (RAN) statically allocates (e.g., allocates on a recurrent or periodic basis) portions of the shared radio spectrum to each RAT implemented by base stations with overlapping cells and/or coverage areas. To illustrate, assume that the first RAT and the second RAT utilize common partitioning of the air interface resources, such as those described with reference to <FIG>. Assume, also, that a first base station implements a first cell using a first RAT and a second base station implements a second cell using a second RAT, where the first cell and the second cell at least partially overlap (e.g., a first cell/coverage area of the first cell at least partially overlaps with a second cell/coverage area of the second cell). Using the common partitioning of the air interface resources, the first base station accesses the shared radio spectrum based on a first time duration, a first resource block, and/or a first frequency portion of the shared radio spectrum as statically allocated by the network operator. Similarly, the second base station accesses the shared radio spectrum based on a second time duration, a second resource block, and/or a second frequency portion of the shared radio spectrum as allocated by the network operator. Statically allocating these portions allows each RAT to access the shared radio spectrum on a periodic basis (e.g., frame-by-frame) for time-based allocations and/or continuously for frequency-based allocations. In aspects, a Radio Access Network (RAN) statically allocates the portions to each RAT implemented by one or more base station(s). Alternatively, or additionally, the RAN (statically) reallocates the portions based on cell capacity at each base station increasing or decreasing.

Static allocations of shared radio spectrum sometimes lead to inefficient use of the radio spectrum. For example, assume the first base station in the RAN has zero attached UEs while the second base station in the RAN covers a similar geographic area and has multiple attached UEs. Assume also that a first cell/coverage area provided by the first base station partially or fully overlaps with a second cell/coverage area provided by the second base station. In this example, the portion of the shared radio spectrum allocated to the first base station remains unused and leads to inefficient use of the radio spectrum while the second base station reaches capacity (e.g., a maximum number of UEs the second base station can serve) and potentially declines serving additional UEs.

In aspects of enhanced uplink spectrum sharing, a base station communicates, to a user equipment (UE), a second air interface resource configuration (e.g., a physical uplink control channel (PUCCH) resource configuration) for a second air interface resource (e.g., a second PUCCH resource) allocated to a second cell that uses a second radio access technology (RAT) and implemented by the base station. The base station receives a first air interface resource configuration (e.g., a first PUCCH resource configuration) for a first air interface resource (e.g., a first PUCCH resource) allocated to a first cell that uses a first RAT, where the first air interface resource configuration differs from the second air interface resource. In aspects, the base station communicates the first air interface resource configuration to the UE. Based on receiving a low-utilization indication for the first air interface resource, the base station directs the UE to utilize the first air interface resource for transmitting uplink communications using the second RAT.

Dynamically sharing statically allocated uplink air interface resources allows participating devices, such as base stations and corresponding UEs, to improve the utilization of the air interface resources. In turn, this increases the capacity and reliability of the corresponding wireless networks by dynamically providing the unused air interface resources to other devices for use.

<FIG> illustrates an example environment <NUM>, which includes a user equipment <NUM> (UE <NUM>) that can communicate with base stations <NUM> (illustrated as base stations <NUM> and <NUM>) through one or more wireless communication links <NUM> (wireless links <NUM>), illustrated as wireless links <NUM> and <NUM>. For simplicity, the UE <NUM> is implemented as a smartphone but may be implemented as any suitable computing or electronic device, such as a mobile communication device, modem, cellular phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, smart appliance, vehicle-based communication system, or an Internet-of Things (IoT) device such as a sensor or an actuator. The base stations <NUM> (e.g., an Evolved Universal Terrestrial Radio Access Network Node B, E-UTRAN Node B, evolved Node B, eNodeB, eNB, Next Generation Node B, gNode B, gNB, ng-eNB, or the like) may be implemented in a macrocell, microcell, small cell, picocell, distributed base station, and the like, or any combination thereof.

The base stations <NUM> communicate with the UE <NUM> using the wireless links <NUM> and/or <NUM>, which may be implemented as any suitable type of wireless link. The wireless links <NUM> and <NUM> include control-plane information and/or user-plane data, such as downlink of user-plane data and control-plane information communicated from the base stations <NUM> to the UE <NUM>, uplink of other user-plane data and control-plane information communicated from the UE <NUM> to the base stations <NUM>, or both. The wireless links <NUM> may include one or more wireless links (e.g., radio links) or bearers implemented using any suitable communication protocol or standard, or combination of communication protocols or standards, such as Third Generation Partnership Project Long-Term Evolution (3GPP LTE), Fifth Generation New Radio (5GNR), and so forth. Multiple wireless links <NUM> may be aggregated in a carrier aggregation or multi-connectivity technology to provide a higher data rate for the UE <NUM>. Multiple wireless links <NUM> from multiple base stations <NUM> may be configured for Coordinated Multipoint (CoMP) communication with the UE <NUM>.

The base stations <NUM> are collectively a Radio Access Network <NUM> (e.g., RAN, Evolved Universal Terrestrial Radio Access Network, E-UTRAN, <NUM> NR RAN, NR RAN), where the RAN <NUM> communicates with one or more core networks <NUM> (core network <NUM>). To illustrate, the base station <NUM> connects, at interface <NUM>, to a <NUM> core network <NUM> (5GC <NUM>) through an NG2 interface for control-plane signaling and using an NG3 interface for user-plane data communications. The base station <NUM> connects, at interface <NUM>, to an Evolved Packet Core <NUM> (EPC <NUM>) using an S1 interface for control-plane signaling and user-plane data communications. Alternatively, or additionally, if the base station <NUM> connects to the 5GC <NUM> core network, the base station <NUM> connects to the 5GC <NUM> using an NG2 interface for control-plane signaling and through an NG3 interface for user-plane data communications, at interface <NUM>. Accordingly, certain base stations <NUM> can communicate with multiple core networks <NUM> (e.g., 5GC <NUM>, EPC <NUM>).

In addition to wireless links to core networks, the base stations <NUM> may communicate with each other. For example, the base stations <NUM> and <NUM> communicate through an Xn interface at interface <NUM> to coordinate proportioning air interface resources as further described.

The UE <NUM> may connect, through the <NUM> core network <NUM> or the Evolved Packet Core Network <NUM>, to public networks, such as the Internet <NUM>, to interact with a remote service <NUM>. The remote service <NUM> represents the computing, communication, and storage devices used to provide any of a multitude of services, including interactive voice or video communication, file transfer, streaming audio, voice, or video, and other technical services implemented in any manner such as voice calls, video calls, website access, messaging services (e.g., text messaging or multimedia messaging), photo file transfer, enterprise software applications, social media applications, video-gaming, streaming video or audio services, and podcasts.

<FIG> illustrates an example device diagram <NUM> of the UE <NUM> and one of the base stations <NUM> that can implement various aspects of enhanced uplink spectrum sharing in a wireless communication system. The UE <NUM> and/or the base station <NUM> may include additional functions and interfaces that are omitted from <FIG> for the sake of clarity.

The UE <NUM> includes antennas <NUM>, a radio frequency front end <NUM> (RF front end <NUM>), and a wireless transceiver (e.g., an LTE transceiver <NUM>, and/or a <NUM> NR transceiver <NUM>) for communicating with the base station <NUM> in the RAN <NUM>. The RF front end <NUM> of the UE <NUM> can couple or connect the LTE transceiver <NUM> and the <NUM> NR transceiver <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> of the UE <NUM> may include an array of multiple antennas that are configured in a manner similar to or different from each other. The antennas <NUM> and the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency bands defined by the 3GPP LTE and <NUM> NR communication standards and implemented by the LTE transceiver <NUM>, and/or the <NUM> NR transceiver <NUM>. Additionally, the antennas <NUM>, the RF front end <NUM>, the LTE transceiver <NUM>, and/or the <NUM> NR transceiver <NUM> may be configured to support beamforming for the transmission and reception of communications with the base station <NUM>. By way of example and not limitation, the antennas <NUM> and the RF front end <NUM> can be implemented for operation in sub-gigahertz (GHz) bands, sub-<NUM> bands, and/or above <NUM> bands that are defined by the 3GPP LTE and <NUM> NR communication standards.

The UE <NUM> also includes processor(s) <NUM> and computer-readable storage media <NUM> (CRM <NUM>). The processor <NUM> may be a single-core processor or a multiple-core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. The computer-readable storage media described herein excludes propagating signals. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the UE <NUM>. The device data <NUM> includes user data, multimedia data, beamforming codebooks, applications, and/or an operating system of the UE <NUM>, some of which are executable by processor(s) <NUM> to enable user-plane data, control-plane information, and user interaction with the UE <NUM>.

The CRM <NUM> of the UE <NUM> includes a UE communication system protocol stack <NUM> (UE protocol stack <NUM>). Alternatively, or additionally, the UE protocol stack <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the UE <NUM>. In aspects, the UE protocol stack <NUM> of the UE <NUM> implements how devices in a communication system exchange information, such as by implementing multiple layers that act as entities for communication with another device using the protocols defined for the layer as further described with reference to <FIG>. In aspects, the UE protocol stack <NUM> processes messages and/or indications from the base station <NUM>, such as a first message that includes a first PUCCH resource configuration for a first PUCCH resource allocated to uplink communications that use a first RAT implemented by the base station <NUM>, a second message that includes a second PUCCH resource configuration for a second PUCCH resource allocated to uplink communications that use a second RAT, and/or a third message (or indication) that directs the UE <NUM> to utilize the second PUCCH resource for uplink communications of the first RAT as further described.

The device diagram for the base station <NUM>, shown in <FIG>, includes a single network node (e.g., a gNode B). The functionality of the base station <NUM> may be distributed across multiple network nodes or devices and may be distributed in any fashion suitable to perform the functions described herein. The nomenclature for this split base station functionality varies and includes terms such as Central Unit (CU), Distributed Unit (DU), Baseband Unit (BBU), Remote Radio Head (RRH), and/or Remote Radio Unit (RRU). The base station <NUM> includes antennas <NUM>, a radio frequency front end <NUM> (RF front end <NUM>), one or more wireless transceivers (e.g., one or more LTE transceivers <NUM>, and/or one or more <NUM> NR transceivers <NUM>) for communicating with the UE <NUM>. The RF front end <NUM> of the base station <NUM> can couple or connect the LTE transceivers <NUM> and the <NUM> NR transceivers <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> of the base station <NUM> may include an array of multiple antennas that are configured in a manner similar to, or different from, each other. The antennas <NUM> and the RF front end <NUM> can be tuned to, and/or be tunable to, one or more frequency bands defined by the 3GPP LTE and <NUM> NR communication standards, and implemented by the LTE transceivers <NUM>, and/or the <NUM> NR transceivers <NUM>. Additionally, the antennas <NUM>, the RF front end <NUM>, the LTE transceivers <NUM>, and/or the <NUM> NR transceivers <NUM> may be configured to support beamforming, such as Massive multiple-input, multiple-output (Massive-MIMO), for the transmission and reception of communications with the UE <NUM>.

The base station <NUM> also includes processor(s) <NUM> and computer-readable storage media <NUM> (CRM <NUM>). The processor <NUM> may be a single-core processor or a multiple-core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the base station <NUM>. The device data <NUM> includes network scheduling data, radio resource management data, beamforming codebooks, applications, and/or an operating system of the base station <NUM>, which are executable by processor(s) <NUM> to enable communication with the UE <NUM>.

In aspects, the CRM <NUM> of the base station <NUM> also includes a base station-communication system protocol stack <NUM> (BS protocol stack <NUM>). Alternatively, or additionally, the BS protocol stack <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the base station <NUM>. At times, the BS protocol stack <NUM> communicates with the UE protocol stack <NUM> using complementary operations, such as those described with reference to <FIG>.

The CRM <NUM> also includes an uplink spectrum sharing manager <NUM>. Alternatively, or additionally, the uplink spectrum sharing manager <NUM> may be implemented in whole or in part as hardware logic or circuitry integrated with or separate from other components of the base station <NUM>. While the diagram <NUM> illustrates the uplink spectrum sharing manager <NUM> separately from the BS protocol stack <NUM>, alternative or additional implementations include aspects of the uplink spectrum sharing manager <NUM> in the BS protocol stack <NUM>.

In some aspects, the uplink spectrum sharing manager <NUM> communicates a PUCCH configuration statically allocated to uplink communication for the base station <NUM> to a second base station <NUM>. Alternatively, or additionally, the uplink spectrum sharing manager <NUM> identifies one or more conditions that indicate low utilization of an uplink air interface resource for the base station <NUM>. Generally, low utilization corresponds to an expected number of transmissions below a threshold value and/or at zero. In aspects, the uplink spectrum sharing manager <NUM> determines an expected number of transmissions that use the uplink air interface resource is below a threshold value and/or is at zero, based on synchronized transmissions.

To illustrate, the uplink spectrum sharing manager <NUM> monitors downlink communications on a Physical Downlink Shared Channel (PDSCH) and identifies an absence of downlink transmissions on the PDSCH over a time interval. In various communication systems, a device receiving the downlink transmissions over the PDSCH (e.g., UE <NUM>) transmits acknowledgment/negative-acknowledgments (ACK/NACKs) to the base station <NUM> using a PUCCH resource allocated for uplink communications to the base station <NUM>. More particularly, the device transmits the ACK/NACKs to the base station synchronously (e.g., within an expected timeframe) such that the base station <NUM> anticipates when to receive the ACK/NACKs. In aspects, the uplink spectrum sharing manager <NUM> identifies the lack of downlink communications over the PDSCH as a condition that indicates (an expected) low utilization of uplink air interface resources, because the lack of downlink PDSCH transmissions indicates a lack of corresponding ACK/NACKs transmitted over the PUCCH. Based on identifying the one or more conditions, the uplink spectrum sharing manager <NUM> directs the second base station to utilize the PUCCH resource allocated to uplink communications for the base station <NUM>. Alternatively, or additionally, the uplink spectrum sharing manager <NUM> indicates a start time to use the PUCCH resource and/or a stop time to cease using the PUCCH resource. In some aspects, the uplink spectrum sharing manager <NUM> communicates a Boolean or toggle field that indicates an availability (e.g., available, unavailable, change in availability) of the PUCCH resource.

In some aspects, the uplink spectrum sharing manager <NUM> receives an indication of a PUCCH resource configuration from the uplink spectrum sharing manager <NUM> of another base station. In other words, the uplink spectrum sharing manager <NUM> receives a PUCCH resource configuration for a PUCCH resource allocated to uplink communications of the other base station. The uplink spectrum sharing manager <NUM> identifies a UE to forward the PUCCH resource configuration to and directs the base station <NUM> to transmit the PUCCH resource configuration to the UE, such as through the BS protocol stack <NUM> and using a radio resource control (RRC) message. To illustrate, the uplink spectrum sharing manager <NUM> identifies a UE based on priority (e.g., a UE exchanging higher-priority communications relative to other UEs attached to the base station <NUM>) or a UE based on loading (e.g., a UE exchanging more user-plane data relative to other UEs attached to the base station <NUM>). Alternatively or additionally, the uplink spectrum sharing manager <NUM> receives an indication of low utilization of the PUCCH resource and determines to use the PUCCH resource allocated to uplink communications for the other base station, such as by identifying that the number of connected UEs exceeds a first threshold value or that the expected uplink communications from an attached UE exceed a second threshold value. In aspects, the uplink spectrum sharing manager <NUM> directs the UE to utilize the PUCCH resource, such as through the BS protocol stack <NUM> and using a Medium Access Control (MAC) control element (CE), a physical downlink control channel (PDCCH) message, layer <NUM> messaging, layer <NUM> messaging, or RRC messages. This can include the uplink spectrum sharing manager <NUM> indicating a start time and/or stop time to the UE as to when to begin using and/or cease using the PUCCH resource allocated for uplink communications to the other base station.

CRM <NUM> also includes a base station manager <NUM>. Alternatively, or additionally, the base station manager <NUM> may be implemented in whole or in part as hardware logic or circuitry integrated with or separate from other components of the base station <NUM>. In at least some aspects, the base station manager <NUM> configures the LTE transceivers <NUM> and the <NUM> NR transceivers <NUM> for communication with the UE <NUM>, as well as communication with a core network, such as the core network <NUM>.

The base station <NUM> also includes an inter-base station interface <NUM>, such as an Xn and/or X2 interface, which the base station manager <NUM> configures to exchange user-plane data, control-plane information, and/or other data/information between other base stations, to manage the communication of the base station <NUM> with the UE <NUM>. The base station <NUM> includes a core network interface <NUM> that the base station manager <NUM> configures to exchange user-plane data, control-plane information, and/or other data/information with core network functions and/or entities.

<FIG> illustrates an air interface resource that extends between a user equipment and a base station that can be used to implement various aspects of enhanced uplink spectrum sharing. The air interface resource <NUM> can be divided into resource units <NUM>, each of which occupies some intersection of frequency spectrum and elapsed time. A portion of the air interface resource <NUM> is illustrated graphically in a grid or matrix having multiple resource blocks <NUM>, including example resource blocks <NUM>, <NUM>, <NUM>, <NUM>. An example of a resource unit <NUM> therefore includes at least one resource block <NUM>. As shown, time is depicted along the horizontal dimension as the abscissa axis, and frequency is depicted along the vertical dimension as the ordinate axis. The air interface resource <NUM>, as defined by a given communication protocol or standard, may span any suitable specified frequency range and/or may be divided into intervals of any specified duration. Increments of time can correspond to, for example, milliseconds (mSec). Increments of frequency can correspond to, for example, megahertz (MHz).

In example operations generally, the base stations <NUM> allocate portions (e.g., resource units <NUM>) of the air interface resource <NUM> for uplink and downlink communications. Each resource block <NUM> of network access resources may be allocated to support respective wireless communication links <NUM> (wireless links <NUM>) of multiple user equipment <NUM>. In the lower-left corner of the grid, the resource block <NUM> may span, as defined by a given communication protocol, a specified frequency range <NUM> and comprise multiple subcarriers or frequency sub-bands. The resource block <NUM> may include any suitable number of subcarriers (e.g., <NUM>) that each correspond to a respective portion (e.g., <NUM>) of the specified frequency range <NUM> (e.g., <NUM>). The resource block <NUM> may also span, as defined by the given communication protocol, a specified time interval <NUM> or time slot (e.g., lasting approximately one-half millisecond or <NUM> orthogonal frequency-division multiplexing (OFDM) symbols). The time interval <NUM> includes subintervals that may each correspond to a symbol, such as an OFDM symbol. As shown in <FIG>, each resource block <NUM> may include multiple resource elements <NUM> (REs) that correspond to, or are defined by, a subcarrier of the frequency range <NUM> and a subinterval (or symbol) of the time interval <NUM>. Alternatively, a given resource element <NUM> may span more than one frequency subcarrier or symbol. Thus, a resource unit <NUM> may include at least one resource block <NUM>, at least one resource element <NUM>, and so forth.

<FIG> illustrates an example block diagram of a wireless network stack model <NUM> (network stack <NUM>) that can be used to implement various aspects of enhanced uplink spectrum sharing. The network stack <NUM> characterizes a communication system for the example environment <NUM> that can be used to implement aspects of adaptive selection of a network access mode by a user equipment. The network stack <NUM> includes a user plane <NUM> and a control plane <NUM>. Upper layers of the user plane <NUM> and the control plane <NUM> share common lower layers in the network stack <NUM>. Wireless devices, such as the UE <NUM> or the base station <NUM>, implement each layer as an entity for communication with another device using the protocols defined for the layer. For example, a UE <NUM> uses a Packet Data Convergence Protocol (PDCP) entity to communicate to a peer PDCP entity in a base station <NUM> using the PDCP.

The shared lower layers include a physical (PHY) layer <NUM>, a Media Access Control (MAC) layer <NUM>, a Radio Link Control (RLC) layer <NUM>, and a PDCP layer <NUM>. The PHY layer <NUM> provides hardware specifications for devices that communicate with each other. Accordingly, the PHY layer <NUM> establishes how devices connect to each other, assists in managing how communication resources are shared among devices and the like.

The MAC layer <NUM> specifies how data is transferred between devices. Generally, the MAC layer <NUM> provides a way in which data packets being transmitted are encoded and decoded into bits as part of a transmission protocol.

The RLC layer <NUM> provides data-transfer services to higher layers in the network stack <NUM>. Generally, the RLC layer <NUM> provides error correction, packet segmentation, and reassembly, and management of data transfers in various modes, such as acknowledged, unacknowledged, or transparent modes.

The PDCP layer <NUM> provides data-transfer services to higher layers in the network stack <NUM>. Generally, the PDCP layer <NUM> provides the transfer of user plane <NUM> and control plane <NUM> data, header compression, ciphering, and integrity protection.

Above the PDCP layer <NUM>, the stack splits into the user plane <NUM> and the control plane <NUM>. Layers of the user plane <NUM> include an optional Service Data Adaptation Protocol (SDAP) layer <NUM>, an Internet Protocol (IP) layer <NUM>, a Transmission Control Protocol/User Datagram Protocol (TCP/UDP) layer <NUM>, and an application layer <NUM>, which transfers data using the interface <NUM>. The optional SDAP layer <NUM> is present in <NUM> NR networks. The SDAP layer <NUM> maps a Quality of Service (QoS) flow for each data radio bearer and marks QoS flow identifiers in uplink and downlink data packets for each packet data session. The IP layer <NUM> specifies how the data from the application layer <NUM> is transferred to a destination node. The TCP/UDP layer <NUM> is used to verify that data packets intended to be transferred to the destination node reached the destination node, using either TCP or UDP for data transfers by the application layer <NUM>. In some implementations, the user plane <NUM> may also include a data services layer (not shown) that provides data transport services to transport application data, such as IP packets including web-browsing content, video content, image content, audio content, or social media content.

The control plane <NUM> includes a Radio Resource Control (RRC) layer <NUM> and a Non-Access Stratum (NAS) layer <NUM>. The RRC layer <NUM> establishes and releases connections and radio bearers, broadcasts system information, or performs power control. The RRC layer <NUM> also controls a resource control state of the UE <NUM> and directs the UE <NUM> to perform operations according to the resource control state. Example resource control states include a connected state (e.g., an RRC connected state) or a disconnected state, such as an inactive state (e.g., an RRC inactive state) or an idle state (e.g., an RRC idle state). In general, if the UE <NUM> is in the connected state, the connection with the base station <NUM> is active. In the inactive state, the connection with the base station <NUM> is suspended. If the UE <NUM> is in the idle state, the connection with the base station <NUM> is released. Generally, the RRC layer <NUM> supports 3GPP access but does not support non-3GPP access (e.g., WLAN communications).

The NAS layer <NUM> provides support for mobility management (e.g., using a Fifth-Generation Mobility Management (5GMM) layer <NUM>) and packet data bearer contexts (e.g., using a Fifth-Generation Session Management (5GSM) layer <NUM>) between the UE <NUM> and entities or functions in the core network, such as an Access and Mobility Management Function of the 5GC <NUM> or the like. The NAS layer <NUM> supports both 3GPP access and non-3GPP access.

In the UE <NUM>, each layer in both the user plane <NUM> and the control plane <NUM> of the network stack <NUM> interacts with a corresponding peer layer or entity in the base station <NUM>, a core network entity or function, and/or a remote service, to support user applications and control operation of the UE <NUM> in the RAN <NUM>.

To increase capacity and deliver reliable wireless connections, evolving communication systems look for new approaches to more efficiently utilize air interface resources. As one example, various RATs oftentimes allocate Physical Uplink Control Channel (PUCCH) resources to a fixed region of a frequency band, such as a top portion of the frequency band and/or a bottom portion of the frequency band. By allocating the PUCCH resources at the edges of a frequency band, the RATs reduce fragmentation and leave a center portion of the frequency band for other transmissions, such as physical uplink shared channel (PUSCH) transmissions that utilize multiple (contiguous) resource blocks.

In aspects of enhanced uplink spectrum sharing, base stations that implement different RATs communicate with one another to dynamically share statically allocated air interface resources, such as sharing a PUCCH resource statically allocated to uplink communications that use a first RAT for use in transmitting uplink communications that use a second RAT. The static allocation of the air interface resources can include time-based allocations that statically divide air interface resources using orthogonal (e.g., separate and non-overlapping) time periods, such as a frame, subframe, or time slot. Alternatively, or additionally, the static allocation can include frequency-based allocations that statically divide air interface resources into orthogonal frequency portions (e.g., subcarriers, frequency sub-bands). As yet another example, the static allocation can include resource-block-based allocations, such as those described with reference to <FIG>. Dynamically sharing the statically allocated uplink air interface resources increases the utilization efficiency of the corresponding air interface resources and results in improved capacity and reliability of wireless connections in the corresponding wireless network.

<FIG> illustrates an example signaling and control transaction diagram <NUM> in accordance with one or more aspects of enhanced uplink spectrum sharing. In aspects, operations of the signaling and control transactions may be performed by any combination of devices, including a first base station <NUM> (e.g., base station <NUM> or base station <NUM>), a second base station <NUM> (e.g., base station <NUM> or base station <NUM>), and the UE <NUM> using aspects as described with reference to any of <FIG>.

In the diagram <NUM>, the base station <NUM> implements a second RAT (RAT2) and the base station <NUM> implements a first RAT (RAT <NUM>), where the second RAT and the first RAT operate in common radio spectrum and utilize common air interface resource partitioning. Alternatively, or additionally, a first cell/coverage area provided by the base station <NUM> at least partially overlaps with a second cell/coverage area provided by base station <NUM>. As one example of common radio spectrum and/or common air interface resource partitioning, assume that RAT <NUM> and RAT2 correspond to <NUM> and <NUM> (or vice versa) and that the base station <NUM> and the base station <NUM> operate in common radio spectrum (e.g., a portion of the sub-<NUM> band) using common air interface resource partitioning, such as that described with reference to <FIG>. Assume, also, that the base station <NUM> and the base station <NUM> reside in a common RAN (e.g., RAN <NUM>). Because the base station <NUM> and the base station <NUM> utilize common air interface resource partitioning and operate in common radio spectrum, a network operator controlling the configuration of the corresponding RAN statically allocates a first portion of the common radio spectrum (e.g., air interface resources, such as PUCCH resources) for RAT1 uplink communications with the base station <NUM> and a second portion of the common radio spectrum (e.g., air interface resources, such as additional PUCCH resources) for RAT2 uplink communications with the base station <NUM>. This can include the network operator allocating the common radio spectrum using any combination of time-based, frequency-based, and/or resource-block-based portioning for the static allocations as further described. While the diagram <NUM> illustrates the base station <NUM> and the base station <NUM> as separate entities, some aspects of enhanced uplink spectrum sharing include co-located elements of the base stations <NUM>, <NUM> (e.g., sharing a same baseband unit, sharing a same baseband processor, or same baseband hardware resources).

As illustrated, at <NUM>, the base station <NUM> communicates a second PUCCH resource configuration for a second PUCCH resource to the UE <NUM>. As one example, the base station <NUM> communicates the second PUCCH resource configuration to the UE <NUM> during an initial access procedure. Alternatively, or additionally, the base station <NUM> communicates the second PUCCH resource configuration to the UE <NUM> after a radio resource control (RRC) configuration/reconfiguration. The base station <NUM> can communicate a common PUCCH configuration that conveys cell-specific PUCCH configuration parameters and/or a UE-specific PUCCH configuration. To illustrate, the base station <NUM> communicates, as the second PUCCH resource configuration, any combination of timing information, PUCCH format parameters, code rates, resource identification (ID), resource block (RB) allocations, PUCCH region, reference signal structure information, coding schemes, and so forth. In some aspects, the second PUCCH resource configuration corresponds to a PUCCH resource statically allocated to uplink control communications of the second RAT to the base station <NUM>, as further described. The base station <NUM> communicates the second PUCCH resource configuration to the UE <NUM> in conformance with the second RAT. In aspects, the base station <NUM> communicates air interface resource configurations based on air interface resource partitioning (e.g., <FIG>) as defined by the second RAT and/or common air interface resource partitioning shared between multiple RATs.

At <NUM>, the base station <NUM> and the UE <NUM> maintain a connection with one another. To illustrate, the UE <NUM> maintains a connection with the base station <NUM> while operating in an RRC_CONNECTED mode or an RRC_INACTIVE mode. In aspects, the UE <NUM> maintains the connection with the base station <NUM> while operating in a standalone mode (e.g., communicating with the base station <NUM> using a single RAT). In other words, the UE <NUM> maintains a connection with the base station <NUM> without a second connection with the base station <NUM> (e.g., without using carrier aggregation (CA), without using dual-connectivity (DC)). Alternatively, the UE <NUM> maintains a connection with the base station <NUM> while operating in a non-standalone mode that can include a second connection with the base station <NUM> or a third base station (not illustrated).

At <NUM>, the base station <NUM> communicates a first PUCCH resource configuration for a first PUCCH resource to the base station <NUM>. To illustrate, the base station <NUM> communicates the first PUCCH resource configuration to the base station <NUM> using an Xn interface (e.g., the interface <NUM>). In aspects, the first PUCCH resource configuration corresponds to a PUCCH resource statically allocated to uplink communications for the first RAT in the second cell supported by the base station <NUM> as further described. The base station <NUM> communicates any combination of configuration parameters to indicate the first PUCCH resource configuration, such as any combination of timing information, PUCCH format parameters, code rates, resource identification (ID), resource block (RB) allocations, PUCCH region, reference signal structure information, coding schemes, and so forth. In aspects, the first PUCCH resource differs from the second PUCCH resource (e.g., the first PUCCH resource does not overlap with the second PUCCH resource in time or frequency). For example, the first PUCCH resource uses a different frequency partition, time duration, coding scheme, and so forth, than the first PUCCH resource. In aspects, the base station <NUM> communicates air interface resource configurations based on air interface resource partitioning (e.g., <FIG>) as defined by the first RAT and/or common air interface resource partitioning shared between multiple RATs.

At <NUM>, the base station <NUM> communicates the first PUCCH resource configuration to the UE <NUM>. In aspects, the base station <NUM> communicates the first PUCCH resource configuration by transmitting the first PUCCH resource configuration to the UE <NUM> in an RRC message, where the base station <NUM> implicitly or explicitly directs the UE <NUM> to refrain from using the first PUCCH resource until receiving a notification to begin using the first PUCCH resource.

At <NUM>, the base station <NUM> detects low utilization of the first PUCCH resource. For instance, the base station <NUM> detects one or more conditions indicative of (an expected) low utilization of uplink resources, such as by detecting an absence of downlink transmissions on a PDSCH over a time interval. To illustrate, the base station <NUM>, by way of the uplink spectrum sharing manager <NUM>, sets a timer and monitors for outgoing downlink transmissions on a PDSCH by the base station <NUM>. If the uplink spectrum sharing manager <NUM> of the base station <NUM> detects an outgoing downlink transmission on the PDSCH, the uplink spectrum sharing manager <NUM> resets the timer. Alternatively, if the timer expires, the uplink spectrum sharing manager <NUM> detects the occurrence of a condition of low utilization (e.g., the absence of downlink transmissions) because the lack of downlink PDSCH transmissions indicates a lack of corresponding ACK/NACKs transmitted over the PUCCH as further described.

At <NUM>, the base station <NUM> indicates (an expected) low utilization of the second PUCCH resource to the base station <NUM>. In aspects, the base station <NUM> indicates the low utilization to the base station <NUM> using an Xn interface (e.g., the interface <NUM>). Alternatively, or additionally, the base station <NUM> communicates one or more time metrics with the indication of low utilization, such as a start-time metric that indicates when the first PUCCH resource will be available to borrow/share, a stop-time metric that indicates when the first PUCCH resource may be unavailable to borrow/share, or a time duration metric that indicates a PUCCH-resource-availability time window. While the diagram <NUM> illustrates the base station <NUM> communicating the second PUCCH resource configuration to the UE <NUM> at <NUM> and prior to communicating the first PUCCH resource configuration at <NUM> (by way of the base station <NUM> and the base station <NUM> communicating at <NUM>), other implementations can include the base station <NUM> communicating the first PUCCH resource configuration to the UE <NUM> prior to communicating the second PUCCH resource configuration at <NUM>.

At <NUM>, the base station <NUM> determines to use the first PUCCH resource. As one example, the base station <NUM> identifies that the number of connected UEs (e.g., maintaining a connection to the base station <NUM> as described at <NUM>) exceeds a first threshold value and determines to use the first PUCCH resource. As another example, the base station <NUM> determines that the expected uplink HARQ feedback (e.g., ACK/NACK signals) from the UE <NUM> exceeds a second threshold value.

At <NUM>, the base station <NUM> directs the UE <NUM> to utilize the first PUCCH resource. For example, the base station <NUM> directs the UE to utilize the first PUCCH resource using Physical Downlink Control Channel (PDCCH) messaging, a Medium Access Control (MAC) Control Element (MAC CE), layer <NUM> signaling, layer <NUM> messaging, or an RRC message. In some aspects, the base station <NUM> indicates a start time and/or stop time to the UE <NUM>, where the start time indicates when to begin using the first PUCCH resource, and the stop time indicates when to cease using the first PUCCH resource. Alternatively or additionally, the base station <NUM> transmits a Boolean or toggle field that indicates the availability (e.g., available, unavailable) of the first PUCCH resource. In aspects, the base station <NUM> communicates the first PUCCH resource configuration of the first PUCCH resource at <NUM> using a first communication mechanism (e.g., an RRC message) that is slower relative to a second communication mechanism (e.g., MAC CE, layer <NUM> signaling, layer <NUM> messages). Alternatively or additionally, the base station <NUM> communicates the first and second PUCCH resource configurations using similar communication mechanisms (e.g., RRC messaging, layer <NUM> signaling, or layer <NUM> messaging).

By communicating <NUM>, the first PUCCH resource configuration to the UE <NUM> separately from directions <NUM> to utilize the first PUCCH resource, the base station <NUM> can quickly respond to the low-utilization indication from the base station <NUM> and direct the UE <NUM> to begin using the first PUCCH resource. To illustrate, a communication <NUM> that includes the first PUCCH resource configuration may utilize more air interface resources relative to a communication <NUM> that directs the UE <NUM> to begin using the first PUCCH resource because the first PUCCH resource configuration includes more information (e.g., air interface resource configuration parameters). Using a separate direction communication <NUM> reduces transmission latencies and improves the efficiency with which the base stations (and corresponding RATs and cells) share the first PUCCH resource.

At <NUM>, the UE <NUM> transmits one or more uplink control communications using the first PUCCH resource, where the UE <NUM> transmits the uplink communications using the second RAT supported by the base station <NUM>. To illustrate, the UE <NUM> transmits one or more ACK/NACKs to the base station <NUM> using the first PUCCH resource, where the ACK/NACKS provide HARQ feedback for downlink PDSCH transmissions from the base station <NUM> (using the second RAT). Alternatively or additionally, the UE <NUM> transmits one or more uplink user-plane data communications using the first PUCCH resource.

Oftentimes, a first UE communicating with a first base station using a first RAT has a different identity (e.g., Cell Radio Network Temporary Identifier (C-RNTI) information) than a second UE communicating with a second base station using a second RAT. In aspects, the UE <NUM> encodes or scrambles uplink transmissions that use the first PUCCH resource with identity information associated with the second RAT. The base station <NUM> then decodes and/or unscrambles the uplink transmission using the identity information (e.g., C-RNTI of the second base station). However, because the base station <NUM> uses different identity information (e.g., C-RNTI of the first base station), the base station <NUM> fails to decode and/or unscramble the uplink transmissions from the UE <NUM> that use the first PUCCH resource and are encoded using the C-RNTI of the second base station.

At <NUM>, the UE <NUM> optionally transmits uplink communications using the second PUCCH resource. This can include the UE <NUM> contemporaneously transmitting uplink communications using the second PUCCH resource with the uplink communication transmitted at <NUM> using the first PUCCH resource. To illustrate, assume at <NUM> that the base station <NUM> communicates a start time and a stop time that defines a PUCCH-resource-availability time window when the UE <NUM> can transmit uplink communications using the first PUCCH resource. In aspects, the UE <NUM> contemporaneously uses the second PUCCH resource and the first PUCCH resource, such as by transmitting uplink control-plane information using the first PUCCH resource while transmitting additional uplink control information using the second PUCCH resource.

At <NUM>, the base station <NUM> optionally detects (expected) utilization of the first PUCCH resource. For example, similar to that described at <NUM>, the base station <NUM> detects one or more transmissions on the PDSCH and identifies the transmissions as indicative of (an expected) utilization of uplink resources (e.g., ACK/NACKs). At <NUM> and based on detecting (expected) utilization of the first PUCCH resource, the base station <NUM> optionally directs the base station <NUM> to cease using the first PUCCH resource and/or indicates that the first PUCCH resource is unavailable. To illustrate, and similar to that described at <NUM>, the base station <NUM> communicates with the base station <NUM> using an Xn interface and directs the base station to cease using the first PUCCH resource and/or that the first PUCCH resource is unavailable. At <NUM>, and based on receiving the directions to cease using the first PUCCH resource, the base station <NUM> directs the UE <NUM> to cease using the first PUCCH resource, such as by communicating the directions using a MAC CE, layer <NUM> signaling, layer <NUM> messaging, or an RRC message as described at <NUM>.

Dynamically sharing statically allocated uplink air interface resources allows participating devices, such as base stations and corresponding UEs, to more efficiently use the air interface resources and improves the capacity and reliability of the corresponding wireless networks.

Example methods <NUM>, <NUM>, and <NUM> are described with reference to <FIG>, <FIG>, and <FIG> in accordance with one or more aspects of enhanced uplink spectrum sharing. <FIG> illustrates an example method <NUM> used to perform aspects of enhanced uplink spectrum sharing, such as sharing a physical uplink control channel (PUCCH) resources allocated to a first cell that uses a first radio access technology (RAT) with a second cell that uses a second RAT implemented by a base station. In some implementations, operations of the method <NUM> are performed by the base station, such as the base station <NUM> of <FIG> and/or the base station <NUM> of <FIG>.

At <NUM>, a base station communicates, to a UE, a second air interface resource configuration for a second air interface resource allocated to a second cell that uses a second RAT. For example, the base station <NUM> communicates a second PUCCH resource configuration for a second PUCCH resource to the UE <NUM> as described at <NUM> of <FIG>. In aspects, the second PUCCH resource configuration uses air interface resource partitioning defined by the second RAT.

At <NUM>, the base station receives a first air interface resource configuration for a first air interface resource allocated to a first cell that uses a first RAT. To illustrate, the base station <NUM> receives a first PUCCH resource configuration from the base station <NUM> as described at <NUM> of <FIG>, where a cell/coverage area provided by the base station <NUM> at least partially overlaps with a cell/coverage area provided by the base station <NUM>. In aspects, the first air interface resource configuration (e.g., the first PUCCH resource configuration) differs from the second air interface resource configuration (e.g., the first PUCCH resource does not overlap with the second PUCCH resource in either time or frequency). In aspects, the first air interface resource configuration uses air interface resource partitioning defined by the first RAT and/or common air interface resource partitioning used by the first RAT and the second RAT.

At <NUM>, the base station communicates the first air interface resource configuration to the UE. For example, as described at <NUM> of <FIG>, the base station <NUM> communicates the first PUCCH resource configuration to the UE <NUM>, such as through an RRC message transmitted using the second RAT implemented by the base station <NUM>.

At <NUM>, the base station receives a low-utilization indication for the first air interface resource. To illustrate, the base station <NUM> receives the low-utilization indication from the base station <NUM> as described at <NUM> of <FIG>.

At <NUM>, the base station directs the UE to utilize the first air interface resource for transmitting uplink communications to the base station using the second RAT. For example, as described at <NUM> of <FIG>, the base station <NUM> directs the UE <NUM> to utilize the first PUCCH resource. In some aspects, the base station <NUM> communicates a start time, stop time, and/or air interface resource availability (e.g., PUCCH-resource-availability) time duration to the UE <NUM>. Alternatively or additionally, the base station <NUM> communicates a toggle field that indicates an availability of the first air interface resource (e.g., the first PUCCH resource).

<FIG> illustrates an example method <NUM> used to perform aspects of enhanced uplink spectrum sharing, such as sharing physical uplink control channel (PUCCH) resources allocated to a first cell that uses a first radio access technology (RAT) with a second cell that uses a second RAT. In some implementations, operations of the method <NUM> are performed by a user equipment, such as the UE <NUM> of <FIG>.

At <NUM>, a UE receives a second air interface resource configuration for a second air interface resource from a base station. For example, as described at <NUM> of <FIG>, the UE <NUM> receives a second PUCCH resource configuration from the base station <NUM> during an initial access procedure, an RRC configuration message, and/or an RRC reconfiguration message. In aspects, the second air interface resource (e.g., the second PUCCH resource) is allocated to a second cell that uses a second RAT, where the second air interface resource configuration uses air interface resource partitioning defined by the second RAT.

At <NUM>, the UE receives, from the base station, a first air interface resource configuration for a first air interface resource allocated to a first cell that uses a first RAT. To illustrate, the UE <NUM> receives a first PUCCH resource configuration from the base station <NUM> as described at <NUM> of <FIG>. Alternatively, or additionally, the first air interface resource configuration differs from the second air interface resource configuration (e.g., the second air interface resource configuration and the first air interface resource configuration do not overlap). In aspects, the first cell and the second cell at least partially overlap. Alternatively, or additionally, the first base station and the second base station include elements (e.g., a baseband unit, a baseband processor) that are co-located. In aspects, the first air interface resource configuration uses air interface resource partitioning defined by the first RAT and/or common air interface resource partitioning utilized by the first RAT and the second RAT.

At <NUM>, the UE receives, from the base station, an indication to utilize the first air interface resource for uplink communications to the base station and using the second RAT. For example, as described at <NUM> of <FIG>, the UE <NUM> receives an indication to utilize the first PUCCH resource from the base station <NUM> in a MAC CE, in PDCCH messaging, layer <NUM> signaling, layer <NUM> messaging, and/or an RRC message. In some aspects, the UE <NUM> receives a start time, a stop time, and/or an air interface resource availability (e.g., a PUCCH-resource-availability) time duration that (collectively or singularly) indicate when to begin and/or cease using the first air interface resource. Alternatively, or additionally, the UE receives a toggle field that indicates an availability (e.g., available, unavailable) of the first air interface resource.

At <NUM>, the UE transmits, to the base station, a first uplink communication of the uplink communications using the first air interface resource and the second RAT. To illustrate, as described at <NUM> of <FIG>, the UE <NUM> transmits an uplink communication to the base station <NUM> using the first PUCCH resource and the second RAT.

<FIG> illustrates an example method <NUM> used to perform aspects of enhanced uplink spectrum sharing, such as sharing a physical uplink control channel (PUCCH) resource statically allocated to a first cell that uses a first radio access technology (RAT) with a second cell that uses a second RAT implemented by the second base station. In some implementations, operations of the method <NUM> are performed by a base station, such as the base station <NUM> of <FIG> and/or the base station <NUM> of <FIG>.

At <NUM>, a first base station communicates, to a second base station, an air interface resource configuration for an air interface resource allocated to a first cell that uses a first RAT. For example, the base station <NUM> communicates a first PUCCH resource configuration to the base station <NUM> as described at <NUM> of <FIG>. In aspects, the first cell/coverage area at least partially overlaps with the second cell/coverage area. At times, the base station <NUM> and the base station <NUM> include elements (e.g., a baseband unit, a baseband processor) that are co-located.

At <NUM>, the first base station detects low utilization of the air interface resource. To illustrate, as described at <NUM> of <FIG>, the base station <NUM> detects one or more conditions that indicate low utilization of the PUCCH resource, such as a lack of downlink communications over the PDSCH.

At <NUM>, the first base station communicates a low-utilization indication to the second base station to direct the second base station to utilize the air interface resource. For example, the base station <NUM> communicates the low-utilization indication to the base station <NUM> as described at <NUM> of <FIG>.

The order in which the method blocks of the method <NUM>, <NUM>, and <NUM> are described are not intended to be construed as a limitation, and any number of the described method blocks can be skipped or combined in any order to implement a method or an alternative method. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of the example methods may be described in the general context of executable instructions stored on computer-readable storage memory that is local and/or remote to a computer processing system, and implementations can include software applications, programs, functions, and the like. Alternatively, or additionally, any of the functionality described herein can be performed, at least in part, by one or more hardware logic components, such as, and without limitation, Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SoCs), Complex Programmable Logic Devices (CPLDs), and the like.

Claim 1:
A method performed by a second base station for sharing air interface resources allocated to a first cell with a second cell, wherein the first cell uses a first radio access technology, RAT and is implemented by a first base station, and the second cell uses a second RAT and is implemented by the second base station, the method comprising:
communicating, to a user equipment, UE, a second air interface resource configuration for a second air interface resource allocated to the second cell that uses the second RAT,
the method being characterized by:
receiving, from the first base station, a first air interface resource configuration for a first air interface resource allocated to the first cell that uses the first RAT, with the first air interface resource configuration being different from the second air interface resource configuration, and with the first cell at least partially overlapping the second cell;
communicating, to the UE, the first air interface resource configuration;
receiving a low-utilization indication for the first air interface resource;
based on receiving the low-utilization indication, directing the UE to utilize the first air interface resource for transmitting uplink communications to the second base station using the second RAT; and
receiving, from the UE, a first uplink communication using the first air interface resource and the second RAT.