Patent Description:
<CIT> relates to a method and apparatus for coexistence among wireless transmit/receive units operating in the same spectrum.

<CIT> relates to systems, methods, and apparatus for configuring a control channel in a wireless network.

<CIT> relates to enabling efficient communication on an unlicensed frequency band.

<CIT> relates to coexistence of multiple systems having transmissions that overlap in the frequency band.

The invention made is described in the embodiments relating to <FIG>.

This disclosure relates generally to providing or participating in authorized shared access between two or more wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, <NUM>th Generation (<NUM>) or new radio (NR) networks, as well as other communications networks. As described herein, the terms "networks" and "systems" may be used interchangeably.

In particular, <NUM> networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for <NUM> NR networks. The <NUM> NR will be capable of scaling to provide coverage (<NUM>) to a massive Internet of things (IoTs) with an ultra-high density (e.g., ~<NUM> nodes/km<NUM>), ultra-low complexity (e.g., ~<NUM> of bits/sec), ultra-low energy (e.g., ~<NUM>+ years of battery life), and deep coverage with the capability to reach challenging locations; (<NUM>) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ~<NUM>% reliability), ultra-low latency (e.g., ~ <NUM>), and users with wide ranges of mobility or lack thereof; and (<NUM>) with enhanced mobile broadband including extreme high capacity (e.g., ~ <NUM> Tbps/km<NUM>), extreme data rates (e.g., multi-Gbps rate, <NUM>+ Mbps user experienced rates), and deep awareness with advanced discovery and optimizations.

The <NUM> NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI); having a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD)/frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO), robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in <NUM> NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than <NUM> FDD/TDD implementations, subcarrier spacing may occur with <NUM>, for example over <NUM>, <NUM>, <NUM>, <NUM>, and the like bandwidth. For other various outdoor and small cell coverage deployments of TDD greater than <NUM>, subcarrier spacing may occur with <NUM> over <NUM>/<NUM> bandwidth. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the <NUM> band, the subcarrier spacing may occur with <NUM> over a <NUM> bandwidth. Finally, for various deployments transmitting with mmWave components at a TDD of <NUM>, subcarrier spacing may occur with <NUM> over a <NUM> bandwidth.

<FIG> is a block diagram illustrating <NUM> network <NUM> including various base stations and UEs configured according to aspects of the present disclosure. The <NUM> network <NUM> includes a number of base stations <NUM> and other network entities. A base station may be a station that communicates with the UEs and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each base station <NUM> may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" can refer to this particular geographic coverage area of a base station and/or a base station subsystem serving the coverage area, depending on the context in which the term is used.

A base station may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A base station for a macro cell may be referred to as a macro base station. A base station for a small cell may be referred to as a small cell base station, a pico base station, a femto base station or a home base station. In the example shown in <FIG>, the base stations 105d and 105e are regular macro base stations, while base stations 105a-105c are macro base stations enabled with one of <NUM> dimension (3D), full dimension (FD), or massive MIMO. Base stations 105a-105c take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. Base station 105f is a small cell base station which may be a home node or portable access point. A base station may support one or multiple (e.g., two, three, four, and the like) cells.

The <NUM> network <NUM> may support synchronous or asynchronous operation.

The UEs <NUM> are dispersed throughout the wireless network <NUM>, and each UE may be stationary or mobile. A UE may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE may be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE may be a device that does not include a UICC. In some aspects, UEs that do not include UICCs may also be referred to as internet of everything (IoE) devices. UEs 115a-115d are examples of mobile smart phone-type devices accessing <NUM> network <NUM> A UE may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs 115e-<NUM> are examples of various machines configured for communication that access <NUM> network <NUM>. A UE may be able to communicate with any type of the base stations, whether macro base station, small cell, or the like. In <FIG>, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE and a serving base station, which is a base station designated to serve the UE on the downlink and/or uplink, or desired transmission between base stations, and backhaul transmissions between base stations.

In operation at <NUM> network <NUM>, base stations 105a-105c serve UEs 115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. Macro base station 105d performs backhaul communications with base stations 105a-105c, as well as small cell, base station 105f. Macro base station 105d also transmits multicast services which are subscribed to and received by UEs 115c and 115d.

<NUM> network <NUM> also support mission critical communications with ultra-reliable and redundant links for mission critical devices, such UE 115e, which is a drone. Redundant communication links with UE 115e include from macro base stations 105d and 105e, as well as small cell base station 105f. Other machine type devices, such as UE 115f (thermometer), UE <NUM> (smart meter), and UE <NUM> (wearable device) may communicate through <NUM> network <NUM> either directly with base stations, such as small cell base station 105f, and macro base station 105e, or in multi-hop configurations by communicating with another user device which relays its information to the network, such as UE 115f communicating temperature measurement information to the smart meter, UE <NUM>, which is then reported to the network through small cell base station 105f. <NUM> network <NUM> may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such as in a vehicle-to-vehicle (V2V) mesh network between UEs 115i-<NUM> communicating with macro base station 105e.

<FIG> shows a block diagram of a design of a base station <NUM> and a UE <NUM>, which may be one of the base station and one of the UEs in <FIG>. At the base station <NUM>, a transmit processor <NUM> may receive data from a data source <NUM> and control information from a controller/processor <NUM>. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit processor <NUM> may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor <NUM> may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor <NUM> may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 232a through 232t. Downlink signals from modulators 232a through 232t may be transmitted via the antennas 234a through 234t, respectively.

At the UE <NUM>, the antennas 252a through 252r may receive the downlink signals from the base station <NUM> and may provide received signals to the demodulators (DEMODs) 254a through 254r, respectively. A MIMO detector <NUM> may obtain received symbols from all the demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols.

On the uplink, at the UE <NUM>, a transmit processor <NUM> may receive and process data (e.g., for the PUSCH) from a data source <NUM> and control information (e.g., for the PUCCH) from the controller/processor <NUM>. The symbols from the transmit processor <NUM> may be precoded by a TX MIMO processor <NUM> if applicable, further processed by the modulators 254a through 254r (e.g., for SC-FDM, etc.), and transmitted to the base station <NUM>. At the base station <NUM>, the uplink signals from the UE <NUM> may be received by the antennas <NUM>, processed by the demodulators <NUM>, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE <NUM>. The processor <NUM> may provide the decoded data to a data sink <NUM> and the decoded control information to the controller/processor <NUM>.

The controller/processor <NUM> and/or other processors and modules at the base station <NUM> may perform or direct the execution of various processes for the techniques described herein. The controllers/processor <NUM> and/or other processors and modules at the UE <NUM> may also perform or direct the execution of the functional blocks illustrated in <FIG>, and/or other processes for the techniques described herein. The memories <NUM> and <NUM> may store data and program codes for the base station <NUM> and the UE <NUM>, respectively.

In some cases, UE <NUM> and base station <NUM> may operate in a shared radio frequency spectrum band, which may include licensed or unlicensed (e.g., contention-based) frequency spectrum. In an unlicensed frequency portion of the shared radio frequency spectrum band, UEs <NUM> or base stations <NUM> may traditionally perform a medium-sensing procedure to contend for access to the frequency spectrum. For example, UE <NUM> or base station <NUM> may perform a listen before talk (LBT) procedure such as a clear channel assessment (CCA) prior to communicating in order to determine whether the shared channel is available. A CCA may include an energy detection procedure to determine whether there are any other active transmissions. For example, a device may infer that a change in a received signal strength indicator (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA also may include detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence. In some cases, an LBT procedure may include a wireless node adjusting its own backoff window based on the amount of energy detected on a channel and/or the acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets as a proxy for collisions.

Use of a medium-sensing procedure to contend for access to an unlicensed shared spectrum may result in communication inefficiencies. This may be particularly evident when multiple network operating entities (e.g., network operators) are attempting to access a shared resource. In <NUM> network <NUM>, base stations <NUM> and UEs <NUM> may be operated by the same or different network operating entities. In some examples, an individual base station <NUM> or UE <NUM> may be operated by more than one network operating entity. In other examples, each base station <NUM> and UE <NUM> may be operated by a single network operating entity. Requiring each base station <NUM> and UE <NUM> of different network operating entities to contend for shared resources may result in increased signaling overhead and communication latency.

<FIG> illustrates an example of a timing diagram <NUM> for coordinated resource partitioning. The timing diagram <NUM> includes a superframe <NUM>, which may represent a fixed duration of time (e.g., <NUM>). Superframe <NUM> may be repeated for a given communication session and may be used by a wireless system such as <NUM> network <NUM> described with reference to <FIG>. The superframe <NUM> may be divided into intervals such as an acquisition interval (A-INT) <NUM> and an arbitration interval <NUM>. As described in more detail below, the A-INT <NUM> and arbitration interval <NUM> may be subdivided into sub-intervals, designated for certain resource types, and allocated to different network operating entities to facilitate coordinated communications between the different network operating entities. For example, the arbitration interval <NUM> may be divided into a plurality of sub-intervals <NUM>. Also, the superframe <NUM> may be further divided into a plurality of subframes <NUM> with a fixed duration (e.g., <NUM>). While timing diagram <NUM> illustrates three different network operating entities (e.g., Operator A, Operator B, Operator C), the number of network operating entities using the superframe <NUM> for coordinated communications may be greater than or fewer than the number illustrated in timing diagram <NUM>.

The A-INT <NUM> may be a dedicated interval of the superframe <NUM> that is reserved for exclusive communications by the network operating entities. In some examples, each network operating entity may be allocated certain resources within the A-INT <NUM> for exclusive communications. For example, resources <NUM>-a may be reserved for exclusive communications by Operator A, such as through base station 105a, resources <NUM>-b may be reserved for exclusive communications by Operator B, such as through base station 105b, and resources <NUM>-c may be reserved for exclusive communications by Operator C, such as through base station 105c. Since the resources <NUM>-a are reserved for exclusive communications by Operator A, neither Operator B nor Operator C can communicate during resources <NUM>-a, even if Operator A chooses not to communicate during those resources. That is, access to exclusive resources is limited to the designated network operator. Similar restrictions apply to resources <NUM>-b for Operator B and resources <NUM>-c for Operator C. The wireless nodes of Operator A (e. g, UEs <NUM> or base stations <NUM>) may communicate any information desired during their exclusive resources <NUM>-a, such as control information or data.

When communicating over an exclusive resource, a network operating entity does not need to perform any medium sensing procedures (e.g., listen-before-talk (LBT) or clear channel assessment (CCA)) because the network operating entity knows that the resources are reserved. Because only the designated network operating entity may communicate over exclusive resources, there may be a reduced likelihood of interfering communications as compared to relying on medium sensing techniques alone (e.g., no hidden node problem). In some examples, the A-INT <NUM> is used to transmit control information, such as synchronization signals (e.g., SYNC signals), system information (e.g., system information blocks (SIBs)), paging information (e.g., physical broadcast channel (PBCH) messages), or random access information (e.g., random access channel (RACH) signals). In some examples, all of the wireless nodes associated with a network operating entity may transmit at the same time during their exclusive resources.

In some examples, resources may be classified as prioritized for certain network operating entities. Resources that are assigned with priority for a certain network operating entity may be referred to as a guaranteed interval (G-INT) for that network operating entity. The interval of resources used by the network operating entity during the G-INT may be referred to as a prioritized sub-interval. For example, resources <NUM>-a may be prioritized for use by Operator A and may therefore be referred to as a G-INT for Operator A (e.g., G-INT-OpA). Similarly, resources <NUM>-b may be prioritized for Operator B, resources <NUM>-c may be prioritized for Operator C, resources <NUM>-d may be prioritized for Operator A, resources <NUM>-e may be prioritized for Operator B, and resources <NUM>-f may be prioritized for operator C.

The various G-INT resources illustrated in <FIG> appear to be staggered to illustrate their association with their respective network operating entities, but these resources may all be on the same frequency bandwidth. Thus, if viewed along a time-frequency grid, the G-INT resources may appear as a contiguous line within the superframe <NUM>. This partitioning of data may be an example of time division multiplexing (TDM). Also, when resources appear in the same sub-interval (e.g., resources <NUM>-a and resources <NUM>-b), these resources represent the same time resources with respect to the superframe <NUM> (e.g., the resources occupy the same sub-interval <NUM>), but the resources are separately designated to illustrate that the same time resources can be classified differently for different operators.

When resources are assigned with priority for a certain network operating entity (e.g., a G-INT), that network operating entity may communicate using those resources without having to wait or perform any medium sensing procedures (e.g., LBT or CCA). For example, the wireless nodes of Operator A are free to communicate any data or control information during resources <NUM>-a without interference from the wireless nodes of Operator B or Operator C.

A network operating entity may additionally signal to another operator that it intends to use a particular G-INT. For example, referring to resources <NUM>-a, Operator A may signal to Operator B and Operator C that it intends to use resources <NUM>-a. Such signaling may be referred to as an activity indication. Moreover, since Operator A has priority over resources <NUM>-a, Operator A may be considered as a higher priority operator than both Operator B and Operator C. However, as discussed above, Operator A does not have to send signaling to the other network operating entities to ensure interference-free transmission during resources <NUM>-a because the resources <NUM>-a are assigned with priority to Operator A.

Similarly, a network operating entity may signal to another network operating entity that it intends not to use a particular G-INT. This signaling may also be referred to as an activity indication. For example, referring to resources <NUM>-b, Operator B may signal to Operator A and Operator C that it intends not to use the resources <NUM>-b for communication, even though the resources are assigned with priority to Operator B. With reference to resources <NUM>-b, Operator B may be considered a higher priority network operating entity than Operator A and Operator C. In such cases, Operators A and C may attempt to use resources of sub-interval <NUM> on an opportunistic basis. Thus, from the perspective of Operator A, the sub-interval <NUM> that contains resources <NUM>-b may be considered an opportunistic interval (O-INT) for Operator A (e.g., O-INT-OpA). For illustrative purposes, resources <NUM>-a may represent the O-INT for Operator A. Also, from the perspective of Operator C, the same sub-interval <NUM> may represent an O-INT for Operator C with corresponding resources <NUM>-b. Resources <NUM>-a, <NUM>-b, and <NUM>-b all represent the same time resources (e.g., a particular sub-interval <NUM>), but are identified separately to signify that the same resources may be considered as a G-INT for some network operating entities and yet as an O-INT for others.

To utilize resources on an opportunistic basis, Operator A and Operator C may perform medium-sensing procedures to check for communications on a particular channel before transmitting data. For example, if Operator B decides not to use resources <NUM>-b (e.g., G-INT-OpB), then Operator A may use those same resources (e.g., represented by resources <NUM>-a) by first checking the channel for interference (e.g., LBT) and then transmitting data if the channel was determined to be clear. Similarly, if Operator C wanted to access resources on an opportunistic basis during sub-interval <NUM> (e.g., use an O-INT represented by resources <NUM>-b) in response to an indication that Operator B was not going to use its G-INT, Operator C may perform a medium sensing procedure and access the resources if available. In some cases, two operators (e.g., Operator A and Operator C) may attempt to access the same resources, in which case the operators may employ contention-based procedures to avoid interfering communications. The operators may also have sub-priorities assigned to them designed to determine which operator may gain access to resources if more than operator is attempting access simultaneously.

In some examples, a network operating entity may intend not to use a particular G-INT assigned to it, but may not send out an activity indication that conveys the intent not to use the resources. In such cases, for a particular sub-interval <NUM>, lower priority operating entities may be configured to monitor the channel to determine whether a higher priority operating entity is using the resources. If a lower priority operating entity determines through LBT or similar method that a higher priority operating entity is not going to use its G-INT resources, then the lower priority operating entities may attempt to access the resources on an opportunistic basis as described above.

In some examples, access to a G-INT or O-INT may be preceded by a reservation signal (e.g., request-to-send (RTS)/clear-to-send (CTS)), and the contention window (CW) may be randomly chosen between one and the total number of operating entities.

In some examples, an operating entity may employ or be compatible with coordinated multipoint (CoMP) communications. For example an operating entity may employ CoMP and dynamic time division duplex (TDD) in a G-INT and opportunistic CoMP in an O-INT as needed.

In the example illustrated in <FIG>, each sub-interval <NUM> includes a G-INT for one of Operator A, B, or C. However, in some cases, one or more sub-intervals <NUM> may include resources that are neither reserved for exclusive use nor reserved for prioritized use (e.g., unassigned resources). Such unassigned resources may be considered an O-INT for any network operating entity, and may be accessed on an opportunistic basis as described above.

In some examples, each subframe <NUM> may contain <NUM> symbols (e.g., <NUM>-µs for <NUM> tone spacing). These subframes <NUM> may be standalone, self-contained Interval-Cs (ITCs) or the subframes <NUM> may be a part of a long ITC. An ITC may be a self-contained transmission starting with a downlink transmission and ending with a uplink transmission. In some embodiments, an ITC may contain one or more subframes <NUM> operating contiguously upon medium occupation. In some cases, there may be a maximum of eight network operators in an A-INT <NUM> (e.g., with duration of <NUM>) assuming a <NUM>-µs transmission opportunity.

Although three operators are illustrated in <FIG>, it should be understood that fewer or more network operating entities may be configured to operate in a coordinated manner as described above. In some cases, the location of the G-INT, O-INT, or A-INT within superframe <NUM> for each operator is determined autonomously based on the number of network operating entities active in a system. For example, if there is only one network operating entity, each sub-interval <NUM> may be occupied by a G-INT for that single network operating entity, or the sub-intervals <NUM> may alternate between G-INTs for that network operating entity and O-INTs to allow other network operating entities to enter. If there are two network operating entities, the sub-intervals <NUM> may alternate between G-INTs for the first network operating entity and G-INTs for the second network operating entity. If there are three network operating entities, the G-INT and O-INTs for each network operating entity may be designed as illustrated in <FIG>. If there are four network operating entities, the first four sub-intervals <NUM> may include consecutive G-INTs for the four network operating entities and the remaining two sub-intervals <NUM> may contain O-INTs. Similarly, if there are five network operating entities, the first five sub-intervals <NUM> may contain consecutive G-INTs for the five network operating entities and the remaining sub-interval <NUM> may contain an O-INT. If there are six network operating entities, all six sub-intervals <NUM> may include consecutive G-INTs for each network operating entity. It should be understood that these examples are for illustrative purposes only and that other autonomously determined interval allocations may be used.

It should be understood that the coordination framework described with reference to <FIG> is for illustration purposes only. For example, the duration of superframe <NUM> may be more or less than <NUM>. Also, the number, duration, and location of sub-intervals <NUM> and subframes <NUM> may differ from the configuration illustrated. Also, the types of resource designations (e.g., exclusive, prioritized, unassigned) may differ or include more or less sub-designations.

Different regions may have different regulatory requirements for communication operations over an unlicensed band. Some regulations may mandate the equipment operating on unlicensed spectrum to implement an LBT procedure, such as by performing a clear channel assessment (CCA), before starting a transmission to verify that the operating channel is not occupied. On the unlicensed <NUM> band, two of modes of operation have been suggested: frame-based equipment (FBE), and load-based equipment (LBE).

FBE is the equipment in which the transmit/receive structure may not be directly demand-driven, but, instead, operates according to fixed timing. LBT/CCA may therefore be performed periodically at predefined time instances according to a predetermined frame structure, such as:
Fixed-Frame Period = channel occupancy time (CoT) + idle period (<NUM>) Where the fixed frame period (e.g., <NUM> - <NUM>) represents the periodicity over which the LBT/CCA may be performed, the CoT represents the total time during which equipment has transmissions during the fixed-frame period on a given channel without re-evaluating the availability of that channel, and the idle period represents the total time within the fixed-frame period, during which the equipment has no transmissions. Some regulations provide that the idle period should be at least <NUM>% of the channel occupancy time in any given fixed-frame period. If the equipment finds the operating channel(s) to be clear, it may then transmit immediately. Otherwise, if the equipment finds the operating channel occupied, it would not transmit on that channel during the remainder of the current fixed-frame period.

Unlike for FBE, load-based equipment is not restricted to perform LBT/CCA according to a fixed frame structure. Instead, LBE may perform LBT/CCA on an ad hoc basis, whenever it has data to transmit. Before a transmission on an operating channel, an LBE would perform a CCA to detect the energy on the channel. If the equipment finds the operating channel(s) to be clear, it may transmit immediately. The total time that an LBE makes use of an operating channel is the maximum channel occupancy time (MCOT). In one example implementation, MCOT may be less than (<NUM>/<NUM>) x q milliseconds, where q = {<NUM>. , when q=<NUM>, the MCOT = <NUM>). Otherwise, if the equipment finds an operating channel occupied, it will not immediately transmit on the channel, but will perform an Extended CCA (ECCA) at a later time during the MCOT. For example, the LBE would observe the operating channel for the duration of a random factor N multiplied by the CCA observation time. N represents the number of clear idle slots resulting in a total idle period that the LBE would observe before initiation of the transmission. The value of N may be randomly selected in the range l. q every time an ECCA is to be performed. N may be stored in a counter which is decremented every time a CCA slot is considered to be "unoccupied". When the counter reaches zero, the LBT may transmit.

<NUM> technologies include provision for an Internet of Things (IoT) functionality that allows structured communications over licensed and unlicensed spectrum by multiple dedicated UEs, which may be lower power, single purposes devices (measurement instruments, appliances, industrial equipment, and the like). When implemented for industrial IoT, there may be a single operator environment, for which an FBE-mode of operation may be beneficial.

In FBE-mode operations, if a base station does not contend for access at the beginning of a frame, it may not be able to contend in the middle of the frame thereafter. Thus, without the ability to grab a communication channel in the middle of a designated frame, such FBE-mode operations could not handle urgent traffic, such as ultra-reliable low latency communication (URLLC) traffic.

In addition, an opportunistic frequency switching has been proposed for FBE-mode operations, in which a base station may switch to another frequency when the current frequency suffers from interference. If a served UE does not decode any common signal from the base station, the UE will retune to another carrier frequency and monitor for common signaling on the other frequency. Additional UE complexity may be created if a given base station does not send common signaling at the beginning of a frame. Various aspects of the present disclosure are directed providing aligned LBT gaps and having base stations contend for and transmit short downlink control signaling at the beginning of frame, even if there is no current traffic need. The base station may not know there will be arrival of traffic later on in the fixed-frame period.

<FIG> is a block diagram illustrating example blocks executed by a base station to implement one aspect of the present disclosure. The example blocks will also be described with respect to base station <NUM> as illustrated in <FIG> is a block diagram illustrating base station <NUM> configured according to one aspect of the present disclosure. Base station <NUM> includes the structure, hardware, and components as illustrated for base station <NUM> of <FIG>. For example, base station <NUM> includes controller/processor <NUM>, which operates to execute logic or computer instructions stored in memory <NUM>, as well as controlling the components of base station <NUM> that provide the features and functionality of base station <NUM>. Base station <NUM>, under control of controller/processor <NUM>, transmits and receives signals via wireless radios 900a-t and antennas 234a-t. Wireless radios 900a-t includes various components and hardware, as illustrated in <FIG> for base station <NUM>, including modulator/demodulators 232a-t, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, and TX MIMO processor <NUM>.

At block <NUM>, a base station determines a plurality of potential transmission bursts within a fixed frame period in an FBE mode network. Within the fixed frame period, there may be many opportunities for transmission bursts, including both downlink and uplink transmission bursts. The base station, such as base station <NUM>, may determine an uplink-downlink configuration <NUM> for the potential transmission bursts that schedules transmission locations or slots within which a transmission burst may be made. Base station <NUM> stores the determined uplink-downlink configuration <NUM> in memory <NUM>.

At block <NUM>, the base station reserves a plurality of LBT gaps before a starting position of each burst of the plurality of potential downlink-uplink bursts. Before transmissions on the operating channel, each transmitting entity will perform an LBT procedures (e.g., a regular or abbreviated LBT). Base station <NUM>, under control of controller/processor <NUM>, executes LBT gap scheduling logic <NUM>, stored in memory <NUM>. The execution environment of LBT gap scheduling logic <NUM> allows for scheduler <NUM> to schedule the locations of the LBT gaps prior to each potential transmission burst location. After determining the potential transmission bursts and uplink-downlink configuration, base station <NUM>, under control of controller/processor <NUM> and scheduler <NUM>, may reserve locations for LBT gaps before each potential transmission burst location.

At block <NUM>, the base station communicates a location of the plurality of LBT gaps to one or more network entities connected for communication on the FBE mode network. As a part of the system information, base station <NUM> would communicate the location of the LBT gaps and uplink-downlink configuration <NUM> via wireless radios 900a-t and antennas 234a-t. Communication of the gaps allows any transmitting entity knowledge of the gap in order to perform the LBT prior to its transmission burst.

At block <NUM>, the base station contends for access to the fixed frame period at a beginning of the fixed frame period. Base station <NUM>, under control of controller/processor <NUM> executes LBT logic <NUM>, stored in memory <NUM>. The execution environment of LBT logic <NUM> provides for appropriate energy/preamble detection to be performed in order to detect whether or not the channel is occupied. After performing a successful LBT procedure during the idle period of the previous fixed frame period, base station <NUM> will contend for access at the beginning of the fixed frame period and transmit a common control signal indicating that the channel is available for communication. Base station <NUM> contends for access regardless of whether it has data or knows of data to be communicated later in the fixed frame period.

<FIG> is a block diagram illustrating example block executed by a UE to implement one aspect of the present disclosure. The example blocks will also be described with respect to UE <NUM> as illustrated in <FIG> is a block diagram illustrating UE <NUM> configured according to one aspect of the present disclosure. UE <NUM> includes the structure, hardware, and components as illustrated for UE <NUM> of <FIG>. For example, UE <NUM> includes controller/processor <NUM>, which operates to execute logic or computer instructions stored in memory <NUM>, as well as controlling the components of UE <NUM> that provide the features and functionality of UE <NUM>. UE <NUM>, under control of controller/processor <NUM>, transmits and receives signals via wireless radios 1000a-r and antennas 252a-r. Wireless radios 1000a-r includes various components and hardware, as illustrated in <FIG> for UE <NUM>, including modulator/demodulators 254a-r, MIMO detector <NUM>, receive processor <NUM>, transmit processor <NUM>, and TX MIMO processor <NUM>.

At block <NUM>, a UE receives a location of a plurality of LBT gaps within a fixed frame period on a FBE mode network. For a UE, such as UE <NUM>, within the FBE-mode operation of the network, it will receive signals via antennas 252a-r and wireless radios 1000a-r that identify a location of LBT gaps prior to each potential transmission burst location in the fixed-frame period. UE <NUM> stores record of the gaps in memory <NUM>, at LBT gaps <NUM>. If UE <NUM> were scheduled for uplink transmission during one of the uplink portions or slots of the fixed-frame period as indicated by uplink-downlink configuration <NUM>, stored in memory <NUM>, it would perform LBT during the gap prior to transmission. UE <NUM>, under control of controller/processor <NUM>, would execute LBT logic <NUM>. The execution environment of LBT logic <NUM> provides for UE <NUM> to perform the energy/preamble detection process, as described above, in order to complete an LBT procedure. The location of the LBT gaps may be received in a form of a map of locations or via a set of resources for rate matching around.

At block <NUM>, the UE refrains from transmissions during the location of the plurality of LBT gaps. With the location of each LBT gap, in order to preserve the gaps for LBT by transmitting entities, each network entity would refrain from transmissions during the LBT gap identified by the received location. UE <NUM>, under control of controller/processor <NUM>, would refrain either by using a map of the gaps within which it would not transmit or would identify resources around which it would rate match in LBT gaps <NUM> and, thus, not transmit.

At block <NUM>, the UE detects a common control signal from the serving base station at a beginning of the fixed frame period, wherein the common control signal identifies the fixed frame period is available for transmission according to an uplink-downlink configuration. UE <NUM>, under control of controller/processor <NUM>, executes FBE access logic <NUM>, stored in memory <NUM>. The execution environment of FBE access logic <NUM> provides for UE <NUM> to listen, via antennas 252a-r and wireless radios 1000a-r, at the beginning of each fixed frame period to detect for the common signaling from the serving base station. If UE <NUM> detects the common signaling, it is aware that communications may occur during the fixed frame period. Otherwise, UE <NUM>, under control of controller/processor <NUM>, would retune to a different frequency known within the execution environment of FBE access logic <NUM> as part of the network. UE <NUM> would monitor again on the new frequency for the common signaling.

<FIG> is a block diagram illustrating a base station <NUM> and UE <NUM> configured according to one aspect of the present disclosure. In the illustrated example, base station <NUM> and UE <NUM> are within a single operator environment operating in FBE mode. Within the idle period prior to fixed frame period <NUM>, base station <NUM> performs LBT <NUM> to determine whether or not the operating channel is occupied. After detecting success of LBT <NUM>, base station <NUM> contends for the operating channel and transmits a common control signal <NUM>. Common control signal <NUM> indicates that base station <NUM> has secured access to the operating channel and that the operating channel is available for communications with the served UEs, including UE <NUM>. However, base station <NUM> does not have any data for downlink transmission to any of the served UEs, including UE <NUM>. According to the present aspect, even though base station <NUM> has no data for transmission, it would still perform LBT <NUM> securing access to the operating channel and communications during fixed frame period <NUM>.

Fixed frame period <NUM> includes CoT <NUM>, which remains mostly empty because of the lace of data, and idle period <NUM>. Base station <NUM> will perform LBT <NUM> during idle time <NUM> in order to detect channel occupancy for fixed frame period <NUM>. After CoT <NUM>, base station <NUM> obtains data scheduled for downlink to UE <NUM>. Once success is detected for LBT <NUM>, base station <NUM> contends for the operating channel again during fixed frame period <NUM> and transmits common control and data <NUM>. Common control and data <NUM> includes the common control signaling that, again, identifies to neighboring network entities that the operating channel is open for communication during fixed frame period <NUM>. It also includes the downlink data identified for UE <NUM>. The empty portion of CoT <NUM> is smaller in fixed frame period <NUM> than fixed frame period <NUM> because of the data available for downlink transmission by base station <NUM>. After CoT <NUM>, fixed frame period <NUM> ends with idle period <NUM>.

It should be noted that, while not shown, base station <NUM> would again perform an LBT procedure during idle period <NUM> to contend for access during the next fixed frame period regardless of whether there is any data at base station <NUM> or known to be received by base station <NUM> for downlink transmissions to any of its served UEs, including UE <NUM>. According to the various aspects of the present disclosure, base station <NUM> would attempt access to the operating channel for each fixed frame period regardless of having any data for transmission.

<FIG> is a block diagram illustrating a base station <NUM> and UE <NUM> operating in FBE mode. Within each fixed frame period of FBE operations, there may be multiple transmission burst occasions, including downlink and uplink transmission bursts. In order to efficiently organize each fixed frame period, such as fixed frame periods <NUM> and <NUM>, base station <NUM> may determine an uplink-downlink configuration, which sets different transmission units, portions, or slots of the fixed frame period identified for either uplink or downlink transmission bursts. The uplink-downlink configuration may further be set by base station <NUM> based on scheduled communications that are known. For example, in fixed frame period <NUM>, base station <NUM> schedules uplink-downlink configuration <NUM> within CoT <NUM>, while it schedules uplink-downlink configuration <NUM> within CoT <NUM> of fixed frame period <NUM>. In order to maintain access to the operating channel, base station <NUM> would perform LBT <NUM> during idle period <NUM> of fixed frame period <NUM> to secure access during fixed frame period <NUM>.

<FIG> is a block diagram illustrating base stations 105f and <NUM> in communication with UEs <NUM> and 115f, respectively, each of which is configured according to one aspect of the present disclosure. Base stations 105f and <NUM> operate within the same industrial facility and are synchronized to each other, but each maintains its own communication scheduling. Transmission stream <NUM> includes the transmissions between base station 105f and UE <NUM>, while transmission stream <NUM> includes the transmission between base station <NUM> and UE 115f. The illustrated communications between the entities cover fixed frame period <NUM> for both transmission streams <NUM> and <NUM>. In FBE operations, each network entity that will transmit within any given fixed frame period would perform an LBT procedure (e.g., regular or one shot LBT) for each transmission burst in COT. With multiple uplink-downlink transmission bursts within fixed frame period <NUM> over both transmission streams <NUM> and <NUM>, consideration should be made to avoid blocking, such as base station to base station blocking, base station to UE blocking, or UE to UE blocking due to LBT. Thus, prior to each transmission burst, the transmitting entity will perform an LBT. A gap for these LBT may be included in the scheduling and configuration of the frame.

In a multi-cell deployment, such as with base stations 105f and <NUM>, the different uplink-downlink configurations, each having reserved LBT gaps prior to the burst location may result in transmissions of one cell colliding with transmissions of another. For example, uplink burst <NUM> from UE 115f collides at <NUM> with the attempted LBT of UE <NUM> during gap <NUM>. Similarly, uplink burst <NUM> from UE <NUM> would collide at <NUM> with an LBT attempt by base station <NUM> in gap <NUM>. Downlink burst <NUM> by base station <NUM> would collide at <NUM> with an LBT attempt by base station 105f at gap <NUM>, and downlink burst <NUM> by base station 105f would collide with an LBT attempt by UE 115f at gap <NUM>. Accordingly, without greater coordination between cells (base stations <NUM> and <NUM>) colliding communications may cause low efficiency communications. UE to base station or base station to UE interference is also possible when the deployment is too dense (e.g., energy detection above a threshold due to signals from a neighbor cell). For a dense factory deployment, base station to base station interference may also be problematic.

It should be noted that within a single cell deployment, the LBT gaps can be easily guaranteed. Between each downlink to uplink and uplink to downlink switching point, a gap is scheduled. For downlink to uplink transitions, there may already be a gap scheduled in NR deployments. For uplink to downlink transitions or TDM uplink transmissions, there may be no gap in NR deployments, but various aspects of the present disclosure may provide for such gaps to be defined.

<FIG> is a block diagram illustrating base stations <NUM> and <NUM> and UEs <NUM> and 115f configured according to one aspect of the present disclosure. Base stations <NUM>/<NUM> and UEs <NUM>/115f operated within an FBE-mode environment. In order to avoid colliding communications between different cells, when operating in such a multiple-cell environment, each LBT gap scheduled within a fixed frame period, such as fixed frame period <NUM>, will be aligned across base stations <NUM> and <NUM>. As illustrated, based on the potential transmission bursts available in fixed frame period <NUM>, base station <NUM> defines an uplink-downlink configuration in transmission stream <NUM> that identifies the starting points <NUM> of each transmission unit or slot (e.g., each uplink or downlink occasion). LBT gaps <NUM> are also scheduled prior to the respective starting point <NUM>. LBT gaps <NUM> are also scheduled across transmission stream <NUM>, between base station <NUM> and UE 115f. LBT gaps <NUM> are aligned between transmission streams <NUM> and <NUM>. Thus, collisions of competing signals between the base station <NUM>-UE <NUM> pair and base station <NUM>-UE 115f pair would be avoided.

In order to communicate the alignment of LBT gaps <NUM>, base station <NUM> may broadcast or transmit not only the uplink-downlink configuration for fixed frame period <NUM>, but the locations of LBT gaps <NUM>. This information may be received by both served UE <NUM> and neighbor UE 115f, and neighbor base station <NUM>. Therefore, all neighboring base stations, including base station <NUM> and <NUM>, would follow the same pattern for LBT gaps <NUM> for RRC configured transmission and grants. That configuration of LBT gaps <NUM> may still change over time, but all base stations within the area would change configurations at the same time.

It should be noted that, in order to avoid cross link interference (e.g., UE <NUM> uplink transmission interfering with downlink transmissions to UE 115f), both base station <NUM> and <NUM> may maintain the same uplink-downlink configuration as well. The uplink-downlink pattern can be regular or irregular, as selected by base station <NUM>.

It should further be noted that no gap may be needed within one downlink burst, while a gap may be needed between multiple TDM uplink transmissions.

Communication of the location of LBT gaps <NUM> by base station <NUM> may be made using system information broadcasts (e.g., MIB, SIBs, etc.) or may be semi-statically transmitted using RRC communications or other transmission grants. In such implementations, base station <NUM> would transmit the direct location/scheduling of LBT gaps <NUM> within fixed frame period <NUM>. In additional aspects of the present disclosure, the location of LBT gaps <NUM> may be implicitly communicated by base station <NUM> via signaling of resources for rate matching. NR networks have both symbol-RB level rate matching and RE-level rate matching capabilities. Symbol-RB level rate matching of a resource set may be supported by a bitmap (e.g., <NUM>-bits, <NUM>-bits, etc.). RE-level rate matching is currently defined for LTE CRS transmission. Both of these NR rate matching functions are for PDSCH rate matching, and while uplink rate matching (e.g., PUSCH, etc.) is not covered, uplink rate matching may also be considered assuming the scheduler has sufficient capabilities.

In single operator FBE mode environment, the concept of aligned LBT gaps across base stations is suggested in the various aspects of the present disclosure. As noted above, the scheduler may enforce LBT gaps <NUM> by including scheduling of the gaps in all RRC configurations and transmission grants. Alternatively, various aspects of the present disclosure may provide for a symbol-level rate matching resource set that is configured to the UE, such as to UE <NUM>, and all other configured or granted transmission/reception will rate match around those symbols of the signaled resource set, in both downlink and uplink transmission bursts. This applies to both DL and UL transmissions. In such an implementation, RRC signaling (e.g., cell-specific or UE-specific) or dynamic L1 signaling in DCI (downlink control information) may be used by base station <NUM> to indicate the symbols to rate match around within fixed frame period <NUM>. Thus, each of served UE <NUM> and neighboring network entities, base station <NUM> and UE 115f would have the specific symbols around which to rate match in order to leave LBT gaps <NUM>.

The functional blocks and modules in <FIG> may comprise processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, etc., or any combination thereof.

Claim 1:
A method (<NUM>) of wireless communication, the method (<NUM>) comprising:
receiving (<NUM>), by a user equipment, UE, from a serving base station, a location of a plurality of listen before talk, LBT, gaps within a fixed frame period on a frame-based equipment, FBE, mode network;
refraining (<NUM>), by the UE, from transmissions during the location of the plurality of LBT gaps;
detecting (<NUM>), by the UE, a common control signal from the serving base station at a beginning of the fixed frame period, wherein the common control signal identifies the fixed frame period is available for transmission according to an uplink-downlink configuration;
identifying, by the UE, data for uplink transmission;
performing, by the UE, a LBT procedure at a gap of the plurality of LBT gaps associated with an uplink transmission segment of the uplink-downlink configuration; and
transmitting, by the UE, the data in the uplink transmission segment in response to success of the LBT procedure.