Patent Description:
<NPL>, relates to a discussion, observation, and proposal on the requirements on listen before talk (LBT) for coexistence and the potential enhancements on LBT mechanism. <CIT> relates to autonomous uplink channel clearance signaling for mobile devices in an unlicensed radio frequency spectrum band.

In the following, each of the described methods, apparatuses, examples, and aspects, which does not fully correspond to the invention as defined in the claims is thus not according to the invention and is, as well as the whole following description, present for illustration purposes only or to highlight specific aspects or features of the claims.

If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label,.

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-<NUM>05c 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, For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time.

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) or internet of things (IoT) 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 (N-B-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. Each modulator <NUM> may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal, 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> of the <NUM> network <NUM> (in <FIG>) 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 the <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>). The 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 <NUM>, 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 (e.g., G-INT-OpB), resources <NUM>-c (e.g., G-INT-OpC) 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 (e.g., resources <NUM>-b), 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. For example, Operator A may have priority over Operator C during sub-interval <NUM> when Operator B is not using resources <NUM>-b (e.g., G-INT-OpB). It is noted that in another sub-interval (not shown) Operator C may have priority over Operator A when Operator B is not using its G-INT.

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-fNTs 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.

In sub-<NUM> NR networks, the channel bandwidth can be up to <NUM>. This channel bandwidth feature for NR networks may be extended to NR unlicensed (NR-U) networks as well. On the other side of the spectrum, the features of <NUM> NR/NR-U networks have been developed to also accommodate communications of low-RF-capable UEs, such as a device limited to <NUM> RF coverage. The concept of bandwidth part (BWP) was included for NR/NR-U operations to facilitate support to these low-RF-capable UEs. However, considering the wide range of bandwidths available, listen before talk (LBT) operations in NR-U may impose challenges for detecting truly available shared spectrum. In order to co-exist with WiFi and license assisted access (LAA) networks, NR-U nodes conduct LBT procedures using a <NUM> granularity (e.g., at an LBT subband). The dynamic/chaotic unlicensed deployment of NR-U operations generally leads to the node checking availability of various an un-predictable numbers of such LBT subbands for each TxOP. Moreover, the particular LBT subband to be monitored is, in general, unpredictable without a specific arrangement of the LBT structure in a multi-channel access environment. Low-RF-capable UEs monitoring a specific subband may lose access opportunities in the current transmission opportunity (TxOP), which can become a significant issue when a base station or an operator is serving only low-RF-capable UEs. One extreme solution has been suggested to simply disable multi-channel access for this particular base station or operator. Unfortunately this may cause an unfairness in access to the shared spectrum.

<FIG> is a block diagram illustrating NR-U network <NUM>. NR-U network <NUM> provides access to a communication spectrum that may be shared by various radio access technologies on an unlicensed basis. Within access competition between both low-RF-capable and higher-RF-capable devices of two different operators (OP <NUM> and OP <NUM>), such as low-RF-capable UE 115f and UE 115b, the LBT configuration of each communication pair (e.g., base station 105a and low-RF-capable UE 115f of OP <NUM>, base station 105b and UE 115b of OP <NUM>) may impact the rate of successful access for each node. For example, as illustrated in <FIG>, the LBT configuration of OP <NUM> provides for its only channel, f1, as the primary channel, while the LBT configuration of OP <NUM> provides the primary channel as f1 and the secondary channel as f2. Thus, each of OP <NUM> and OP2 have the same channel frequency for their respective primary channels. Such a co-primary configuration generally results in lower performance for communications between base station 105a and low-RF-capable UE 115f of OP1 than between base station 105b and 115b of OP <NUM>.

<FIG> is a block diagram illustrating NR-U network <NUM>. As illustrated, the LBT configuration of OP <NUM> provides for f1 as the primary channel, while the LBT configuration of OP <NUM> provides the primary channel of f2 and secondary channel of f1. As such, the primary channels between OP <NUM> and OP <NUM> are interleaved, which gives communications between base station 105a and 115f of OP <NUM> a higher probability of success, while still providing communication opportunities for base station 105b and UE 115b of OP <NUM>. OP <NUM> may strongly favor no sharing of spectrum with OP <NUM> at all, unless a fairness restriction exists to ensure OP <NUM> accessibility. Thus, OP <NUM> may favor disabling such multi-channel access when multiple operators compete for the same communication spectrum.

Various aspects of the present disclosure are directed to enabling or maintaining multi-channel access when single operator operations cannot be guaranteed. The long-term presence of another operator can detected through the reading of WiFi beacons and LAA or NR-U nodes' discovery reference signals (DRS). Furthermore, the short-term presence of WiFi nodes around LAA and NR-U nodes can also be detected through short training field (STF) correlation as found in WiFi preamble signals. The NR-U networks defines the primary and secondary channels, signals low-RF-capable UEs to monitor the primary for LBT clear signals, and then directs the low-RF-capable UEs to re-tune to the secondary channel for communications after the secondary channel is secured by the NR-U base station.

<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 700a-t and antennas 234a-t. Wireless radios 700a-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 enables multi-channel access when single operator operations cannot be guaranteed within a shared communication spectrum. Base station, such as base station <NUM>, of a given operator may detect either the long-term or short-term presence of other operators within its coverage area of the shared communication spectrum. For example, various interference signals may be received at base station <NUM> via antennas 234a-t and wireless radios 700a-t which, under control of controller/processor <NUM>, are determined to originate from interfering transmitters associated with other operators. As such other operators are detected, base station <NUM> executes multi-channel operations feature <NUM>, in memory <NUM>. The execution environment of multi-channel operations feature <NUM> ensures that multi-channel access is enabled or maintained for its served UEs.

At block <NUM>, the base station defines a primary channel and a secondary channels within the shared communication channel. For example, base station <NUM>, under control of controller/processor <NUM>, executes access configuration logic <NUM>, stored in memory <NUM>. The execution environment of access configuration logic <NUM> provides for base station <NUM> to select an LBT configuration for the TxOP that identifies the primary and secondary channels in the shared spectrum.

At block <NUM>, the base station transmits a configuration message to one or more low- RF UEs, wherein the configuration message configures the one or more low-RF UEs to monitor the primary channel for a successful LBT indicator. Within the execution environment of access configuration logic <NUM>, base station <NUM> transmits a configuration message via wireless radios 700a-t and antennas 234a-t to each of its served low-RF-capable UEs. The configuration message identifies the primary and secondary LBT channels and directs the UEs to monitor the primary channel for results of an LBT procedure (e. extended clear channel assessment (ECCA), clear channel assessment (CCA), and the like).

At block <NUM>, the base station performs an LBT procedure on the primary channel and the secondary channel, Base station <NUM>, under control of controller processor <NUM>, executes LBT procedures <NUM>, stored in memory <NUM>. The execution environment of LBT procedures <NUM> provides the functionally for base station <NUM> to perform an LBT procedure. For example, the execution environment of LBT procedure <NUM> allows base station <NUM> to perform an ECCA on the primary channel and a CCA on the secondary channel prior to initiating further communications. As is known in the art, such LBT procedures may be based on energy detection, preamble detection, or the like.

At block <NUM>, the base station signals the low-RF UEs on the primary channel to re-tune to the secondary channel for communication during a current transmission opportunity in response to success of the LBT procedure on the secondary channel. If the LBT procedures are successful on both the primary and secondary channels, base station <NUM>, under control of controller/processor <NUM>, executes re-tuning logic <NUM>, stored in memory <NUM>. The execution environment of re-tuning logic <NUM> provides the functionality to base station <NUM> to transmit signals to the low-RF UEs via wireless radios 700a-t and antennas 234a-t to re-tune to the secondary channel for communications. The re-tuning signal may be issued in the form of commands from base station <NUM>, such as a downlink control information (DCI) signal, over the primary channel to the low-RF UEs to re-tune to the secondary channel or channels for communications in the current TxOP. In order to maintain access to the secondary channel, within the execution environment of re-tuning logic <NUM>, base station <NUM> may perform a reserving function on the secondary channel, such as by transmitting a filler or occupancy signal or transmitting a reservation signal (e.g., RTS/CTS) on the secondary channel via wireless radios 700a-t and antennas 234a-t.

<FIG> is a block diagram illustrating example blocks executed by a low-RF-capable 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 800a-r and antennas 252a-r. Wireless radios 800a-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>, the low-RF UE receives a configuration message from a serving base station. A low-RF UE, such as UE <NUM>, receives the configuration message from the serving base station via antennas 252a-r and wireless radios 800a-r and stores it at access configuration <NUM> in memory <NUM>. The configuration message identifies the primary and secondary LBT channels of the shared spectrum and directs the low-RF UE to monitor the primary channel for results of an LBT procedure.

At block <NUM>, the low-RF UE monitors the primary channel for a LBT indicator in response to the configuration message. With the limited RF capabilities, the low-RF-capable UEs, UE <NUM>, monitor the primary channel using antennas 252a-r and wireless radios 800a-r for indications of a successful LBT, such as an ECCA, CCA, etc..

At block <NUM>, the low-RF UE receives a re-tuning signal on the primary channel, wherein the re-tuning signal instructs the low-RF UE to re-tune to a secondary channel for communications during the current transmission opportunity. When the indication of successful LBT is detected via antennas 252a-r and wireless radios 800a-r, the low-RF UE, UE <NUM>, will further receive a re-tuning signal from the serving base station via antennas 252a-r and wireless radios 800a-r. The re-tuning signal, which may be included in a DCI message, instructs UE <NUM> to re-tune wireless radios 800a-r to the secondary channel, as indicated in access configuration <NUM>. UE <NUM> would then re-tune wireless radios 800a-r to the secondary channel for communications (e.g., uplink or downlink) during the current TxOP. These low-RF UEs, such as UE <NUM>, will tune wireless radios 800a-r back to monitor the primary channel after the current TxOP ends.

It should be noted that the various aspects of the present disclosure are not limited to a DCI based approach for signaling the re-tuning of low-RF UEs, such as UE <NUM>. Any delay that might be associated with DCI signaling may be reduced by providing an embedded indicator into the preamble at the beginning of the TxOP. Such an aspect would be useful where UE <NUM> is capable of performing hard-decoding over the preamble. The number of signaling bits can be reduced by pre-allocating the candidate secondary channel(s) to each low-RF-capable UE, such as UE <NUM>, through prior RRC signaling. For example, a one-bit indication may be sufficient to allocate UE <NUM> to a pre-defined, pre-allocated secondary channel.

<FIG> are block diagrams illustrating multi-channel communications between a base station 105a and a low-RF UE 115f each configured according to aspects of the present disclosure. In each of <FIG>, base station 105a communicates with low-RF UE 115f using primary channel <NUM> and secondary channel <NUM>. After configuring the shared spectrum to select the frequencies of primary channel <NUM> and secondary channel <NUM>, base station 105a transmits the LBT configuration to low-RF UE 115f and instructs low-RF UE 115f to monitor primary channel <NUM> for identification of successful LBT results. Base station <NUM> performs ECCA <NUM> on primary channel <NUM> to secure access, while performing CCA <NUM> on secondary channel <NUM>. When both ECCA <NUM> and CCA <NUM> are detected as successful, base station 105a will signal low-RF UE 115f to re-tune to secondary channel <NUM>. Base station 105a may then use different mechanisms to maintain reservation of secondary channel <NUM>.

As illustrated in <FIG>, base station 105a uses a filler transmission <NUM> to maintain occupation of secondary channel <NUM>. After detecting successful completion of ECCA <NUM> and CCA <NUM>, base station 105a signals low-RF UE 115f to re-tune to secondary channel <NUM>, as noted above. After transmitting this signaling, which may be part of a DCI or a signal in the TxOP preamble, low-RF UE 115f begins the re-tuning processor. During that time, in order to prevent a neighboring cell from occupying secondary channel <NUM>, base station 105a will transmit filler transmission <NUM> on secondary channel <NUM>. Filler transmission <NUM> will occupy or reserve secondary channel <NUM>, such that any neighboring cells that may attempt LBT during that time, will be blocked from transmissions. Thereafter, in <FIG>, base station 105a may transmit downlink <NUM> to any other non-low-RF UEs via primary channel <NUM>, and transmit downlink <NUM> to low-RF UE 115f via secondary channel <NUM>. In <FIG>, base station 105a may transmit downlink <NUM> and receive uplink <NUM> on primary channel <NUM> with a non-low-RF UE, and receive uplink <NUM> on secondary channel <NUM> from low-RF UE 115f.

As illustrated in <FIG>, base station 105a uses a channel reservation signal to maintain occupation of secondary channel <NUM>. The channel reservation signal used by base station 105a in <FIG> is a request-to-send (RTS) <NUM> or clear-to-send (CTS) <NUM>. RTS/CTS signaling can effectively operate to keep neighboring nodes from attempting access to secondary channel <NUM>. In such cases, a related CTS <NUM> may or may not be transmitted on primary channel <NUM>. RTS <NUM>/CTS <NUM> on secondary channel <NUM> are transmitted for any neighboring node listening or available for sharing the shared spectrum of secondary channel <NUM>. Once detected by the neighboring node, the neighboring node may be configured to delay attempted access to secondary channel <NUM> to a next transmission availability or TxOP. Thereafter, in <FIG>, base station 105a may participate in uplink <NUM> and downlink <NUM> on primary channel <NUM> with other non-low-RF UEs and transmit downlink <NUM> to low-RF UE 115f via secondary channel <NUM>. In <FIG>, base station 105a may receive uplink <NUM> on primary channel <NUM> from a non-low-RF UE and receive uplink <NUM> from low-RF UE 115f via secondary channel <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 of wireless communication, the method comprising:
enabling (<NUM>), by a network equipment, multi-channel access when single operator operations cannot be guaranteed within a shared communication spectrum;
defining (<NUM>), by the network equipment, a primary channel and a secondary channel within the shared communication channel;
transmitting (<NUM>), by the network equipment, a configuration message to one or more low-radio frequency, RF, user equipments, UEs,, wherein the configuration message configures the one or more low-RF UEs to monitor the primary channel for a successful listen before talk, LBT, indicator;
performing (<NUM>), by the network equipment, an LBT procedure on the primary channel and the secondary channel; and
signaling (<NUM>), by the network equipment, the one or more low-RF UEs on the primary channel to re-tune to the secondary channel for communication during a current transmission opportunity in response to success of the LBT procedures on both the primary and secondary channels.