WO2018026410A1

WO2018026410A1 - Uplink listen-before-talk for transmission in unlicensed spectrum

Info

Publication number: WO2018026410A1
Application number: PCT/US2017/032547
Authority: WO
Inventors: Abhijeet Bhorkar; Huaning Niu; Jeongho Jeon; Qiaoyang Ye
Original assignee: Intel IP Corporation
Priority date: 2016-08-02
Filing date: 2017-05-12
Publication date: 2018-02-08

Abstract

Described is an apparatus of a User Equipment (UE). The apparatus may comprise a first circuitry, a second circuitry, and a third circuitry. The first circuitry may be operable to process an Uplink (UL) grant to transmit UL sub-frames between a start time and an end time on a channel in an unlicensed spectrum. The second circuitry may be operable to conduct a first Listen-Before-Talk (LBT) procedure, prior to transmission of one or more UL sub- frames. The third circuitry may be operable to transmit one or more UL sub-frames, in response to a completion of the first LBT procedure prior to the end time.

Description

UPLINK LISTEN-BEFORE-TALK FOR TRANSMISSION IN UNLICENSED

SPECTRUM

CLAIM OF PRIORITY

[0001] The present application claims priority under 35 U.S.C. § 119(e) to United

States Provisional Patent Application Serial Number 62/370,062, filed August 2, 2016 and entitled "CAT 4 UL LBT FOR PUSCH TRANSMISSION," which is herein incorporated by reference in its entirety.

BACKGROUND

[0002] A variety of wireless cellular communication systems have been implemented, including a 3rd Generation Partnership Project (3 GPP) Universal Mobile

Telecommunications System, a 3GPP Long-Term Evolution (LTE) system, and a 3GPP LTE- Advanced (LTE-A) system. Next-generation wireless cellular communication systems based upon LTE and LTE-A systems are being developed, such as a fifth generation (5G) wireless system / 5G mobile networks system. Next-generation wireless cellular communication systems may provide support for higher bandwidths in part by supporting higher carrier frequencies, such as centimeter- wave and millimeter-wave frequencies. Next-generation wireless cellular communication systems may also provide support for higher bandwidths in part by using unlicensed spectrum.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The embodiments of the disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. However, while the drawings are to aid in explanation and understanding, they are only an aid, and should not be taken to limit the disclosure to the specific embodiments depicted therein.

[0004] Fig. 1 schematically illustrates a User Equipment (UE) performing a Listen-

Before-Talk (LBT) procedure before Uplink (UL) transmission, in accordance with some embodiments of the disclosure.

[0005] Fig. 2 schematically illustrates a UE performing an LBT before UL transmission, in accordance with some embodiments of the disclosure. [0006] Fig. 3 schematically illustrates an eNB performing a Category 4 (Cat 4) LBT procedure before Downlink (DL) transmission, in accordance with some embodiments of the disclosure.

[0007] Fig. 4 illustrates transmission of UL sub-frames, in accordance with some embodiments of the disclosure.

[0008] Fig. 5 illustrates a scenario in which a Cat 4 LBT is completed substantially prior to a start of a scheduled UL transmission, in accordance with some embodiments of the disclosure.

[0009] Fig. 6 illustrates a scenario in which a Cat 4 LBT is completed immediately prior to a start of a scheduled UL transmission, in accordance with some embodiments of the disclosure.

[0010] Fig. 7 illustrates a scenario in which a Cat 4 LBT is completed (i) subsequent to a start of a scheduled UL transmission and (ii) before a completion of the scheduled UL transmission, in accordance with some embodiments of the disclosure.

[0011] Fig. 8 illustrates a scenario in which a Cat 4 LBT is completed subsequent to a start of a scheduled UL transmission and before a completion of the scheduled UL transmission, where a short LBT is performed prior to UL transmission, in accordance with some embodiments of the disclosure.

[0012] Fig. 9 illustrates a scenario in which a Cat 4 LBT is not completed during a completion of a scheduled UL transmission and an LBT counter is frozen until a next UL grant is detected, in accordance with some embodiments of the disclosure.

[0013] Fig. 10 illustrates a scenario in which a Cat 4 LBT is not completed during a completion of a scheduled UL transmission and an LBT counter is frozen until an end of UL bursts scheduled for multiple UEs on the considered carrier(s), in accordance with some embodiments of the disclosure.

[0014] Fig. 11 illustrates a scenario in which a Cat 4 LBT is completed subsequent to a completion of a scheduled UL transmission and the Cat 4 LBT is not halted, in accordance with some embodiments of the disclosure.

[0015] Fig. 12A illustrates re-transmission of sub-frames in accordance with a Hybrid

Automatic Repeat Request (HARQ) process in which a reference sub-frame is a starting sub- frame of a most recent transmission, where the contention window CW_P is dynamically adjusted based on the re-transmission of the reference sub-frames, in accordance with some embodiments of the disclosure. [0016] Fig. 12B illustrates re-transmission of sub-frames in accordance with a HARQ process in which reference sub-frames are all sub-frames of a most recent transmission, where the contention window CW_P is dynamically adjusted based on the re-transmission of the reference sub-frames, in accordance with some embodiments of the disclosure.

[0017] Fig. 12C illustrates re-transmission of sub-frames in accordance with a HARQ process in which reference sub-frames of two UL bursts are re-transmitted, where the contention window CW_P is dynamically adjusted based on the re-transmission of the reference sub-frames, in accordance with some embodiments of the disclosure.

[0018] Fig. 13 illustrates a table depicting various exemplary types of operations associated with LBTs performed by a UE while transmitting UL sub-frames across multiple channels, in accordance with some embodiments of the disclosure.

[0019] Fig. 14 illustrates an Evolved Node-B (eNB) and a UE, in accordance with some embodiments of the disclosure.

[0020] Fig. 15 illustrates hardware processing circuitries for an eNB that supports a

UE conducting LBTs prior to UL transmission, in accordance with some embodiments of the disclosure.

[0021] Fig. 16 illustrates hardware processing circuitries for a UE for performing

LBT prior to UL transmission in unlicensed spectrum, in accordance with some embodiments of the disclosure.

[0022] Fig. 17 illustrates methods for a UE for performing Cat 4 LBT prior to transmitting UL sub-frames in a channel in the unlicensed spectrum, in accordance with some embodiments of the disclosure.

[0023] Fig. 18 illustrates methods for a UE for dynamically updating a contention window size, in accordance with some embodiments of the disclosure.

[0024] Fig. 19 illustrates methods for a UE for selectively conducting LBTs on multiple channels in the unlicensed spectrum, in accordance with some embodiments of the disclosure.

[0025] Fig. 20 illustrates methods for a UE for selectively conducting independent

Cat 4 LBTs on multiple channels in the unlicensed spectrum, in accordance with some embodiments of the disclosure.

[0026] Fig. 21 illustrates example components of a UE device, in accordance with some embodiments of the disclosure. DETAILED DESCRIPTION

[0027] Various wireless cellular communication systems have been implemented or are being proposed, including a 3rd Generation Partnership Project (3GPP) Universal Mobile Telecommunications System (UMTS), a 3GPP Long-Term Evolution (LTE) system, a 3GPP LTE-Advanced (LTE- A) system, and a 5th Generation wireless / 5th Generation mobile networks (5G) system.

[0028] Successive generations of wireless cellular technology seek to use ever higher data rates. However, usable licensed spectrum is limited. The limits on licensed spectrum have fostered an emerging interest in the operation of LTE systems (and successor systems) in unlicensed spectrum.

[0029] As a result, one major enhancement for LTE has been to enable system operation in unlicensed spectrum via Licensed- Assisted Access (LAA), which may expand system bandwidths by utilizing a flexible Carrier Aggregation (CA) framework introduced for LTE-A systems. In LAA, licensed spectrum is used as an "anchor" to assist

communication in the unlicensed spectrum. While at least part of 3GPP Release 13 LAA may focus on Downlink (DL) transmission in unlicensed carriers, at least part of 3 GPP Release 14 enhanced LAA (eLAA) may focus on UL transmission in unlicensed carriers. In some embodiments, in LAA or eLAA, a primary cell (Pcell) may provide connectivity to a UE in licensed spectrum, whereas a secondary cell (Scell) may provide connectivity in unlicensed spectrum. In some embodiments, a Pcell and an Scell may be collocated, while in some other embodiment, a Pcell and an Scell may not be collocated.

[0030] Enhanced operation of LTE systems in unlicensed spectrum may be supported in future releases and 5G systems. LTE operation in unlicensed spectrum may include LTE operation in unlicensed spectrum via Dual Connectivity (DC), and/or standalone LTE operation systems in unlicensed spectrum.

[0031] LTE-based technology may operate solely in unlicensed spectrum without relying upon an "anchor" in the licensed spectrum, such as in MulteFire™ technology by MulteFire Alliance of Fremont California, USA. Such operation may rely on little to no assistance from licensed-spectrum devices, and may be amenable to lean, self-contained network architectures suitable for neutral deployments where a wide variety of deployments can service a wide variety of devices. In MulteFire™, a Pcell may operate in licensed and/or unlicensed spectrum. Standalone LTE operation in unlicensed spectrum may also combine performance benefits of LTE technology with a relative simplicity of Wi-Fi®-like deployments. (Wi-Fi® is a registered trademark of the Wi-Fi Alliance of Austin, Texas, USA.) Standalone LTE operation may accordingly be a significantly important technology in meeting demands of ever-increasing wireless traffic.

[0032] An unlicensed frequency band of current interest is the 5 GHz band, which has wide spectrum with global common availability. The 5 GHz band in the US may be governed by Unlicensed National Information Infrastructure (U-NII) rules promulgated by the Federal Communications Commission (FCC). The main incumbent systems in the 5 GHz band are Wireless Local Area Networks (WLAN) systems, specifically those based on Institute of Electrical and Electronics Engineers (IEEE) 802.11 a/n/ac technologies, e.g., used for Wi-Fi® networks.

[0033] Since WLAN systems may be deployed both by individuals and operators for carrier-grade access service and data offloading, care should be taken before deployment of competing systems. Listen-Before-Talk (LBT) may be employed in LTE LAA systems and/or MulteFire™ systems to promote fair coexistence with incumbent systems (e.g., WLAN systems). LBT is a procedure whereby a radio transmitter may first sense a medium, then transmit if the medium is sensed to be idle.

[0034] In scheduled-based UL design, a Physical Uplink Shared Channel (PUSCH) transmission may be based upon an explicit UL grant transmission via a Physical Downlink Control Channel (PDCCH), for example via Downlink Control Information (DCI) format 0. In scheduled-based UL LAA design, an Evolved Node-B (eNB) may complete an LBT procedure on a component carrier over which PUSCH is expected. If the LBT at the eNB is successful, the eNB may then transmit the UL grant (e.g., via PDCCH). After receiving the UL grant, a UE may perform an LBT procedure during the allocated time interval. An LBT procedure may be a short LBT, which may span 25 microseconds (μβ), or a Category 4 LBT. If the LBT at the UE is successful, the UE may then transmit PUSCH as scheduled, on the resources indicated by the UL grant.

[0035] In some embodiments, a UL grant may be sent on another licensed carrier

(e.g., via cross-carrier scheduling). In such embodiments, an eNB may not be disposed to perform an LBT procedure for the UL grant transmission, but a UE may be disposed to perform a Category 4 LBT procedure before its own UL transmission.

[0036] In studies of scheduled-based UL LAA design, LAA UL throughput performance has been identified as being noticeably degraded. One reason for performance degradation may be the "double" performance of LBT procedures for UL transmission, wherein both an eNB and a UE perform LBT before transmission of PUSCH. [0037] In the following description, numerous details are discussed to provide a more thorough explanation of embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring embodiments of the present disclosure.

[0038] Note that in the corresponding drawings of the embodiments, signals are represented with lines. Some lines may be thicker, to indicate a greater number of constituent signal paths, and/or have arrows at one or more ends, to indicate a direction of information flow. Such indications are not intended to be limiting. Rather, the lines are used in connection with one or more exemplary embodiments to facilitate easier understanding of a circuit or a logical unit. Any represented signal, as dictated by design needs or preferences, may actually comprise one or more signals that may travel in either direction and may be implemented with any suitable type of signal scheme.

[0039] Throughout the specification, and in the claims, the term "connected" means a direct electrical, mechanical, or magnetic connection between the things that are connected, without any intermediary devices. The term "coupled" means either a direct electrical, mechanical, or magnetic connection between the things that are connected or an indirect connection through one or more passive or active intermediary devices. The term "circuit" or "module" may refer to one or more passive and/or active components that are arranged to cooperate with one another to provide a desired function. The term "signal" may refer to at least one current signal, voltage signal, magnetic signal, or data/clock signal. The meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0040] The terms "substantially," "close," "approximately," "near," and "about" generally refer to being within +/- 10% of a target value. Unless otherwise specified the use of the ordinal adjectives "first," "second," and "third," etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

[0041] It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. [0042] The terms "left," "right," "front," "back," "top," "bottom," "over," "under," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions.

[0043] For the purposes of the present disclosure, the phrases "A and/or B" and "A or

B" mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrase "A, B, and/or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0044] In addition, the various elements of combinatorial logic and sequential logic discussed in the present disclosure may pertain both to physical structures (such as AND gates, OR gates, or XOR gates), or to synthesized or otherwise optimized collections of devices implementing the logical structures that are Boolean equivalents of the logic under discussion.

[0045] In addition, for purposes of the present disclosure, the term "eNB" may refer to a legacy eNB, a next-generation or 5G eNB, an Access Point (AP), a Base Station or an eNB communicating on the unlicensed spectrum, and/or another base station for a wireless communication system. For purposes of the present disclosure, the term "UE" may refer to a legacy UE, a next-generation or 5G UE, an STA, and/or another mobile equipment for a wireless communication system.

[0046] Various embodiments of eNBs and/or UEs discussed below may process one or more transmissions of various types. Some processing of a transmission may comprise receiving, conducting, and/or otherwise handling a transmission that has been received. In some embodiments, an eNB or UE processing a transmission may determine or recognize the transmission's type and/or a condition associated with the transmission. For some embodiments, an eNB or UE processing a transmission may act in accordance with the transmission's type, and/or may act conditionally based upon the transmission's type. An eNB or UE processing a transmission may also recognize one or more values or fields of data carried by the transmission. Processing a transmission may comprise moving the transmission through one or more layers of a protocol stack (which may be implemented in, e.g., hardware and/or software-configured elements), such as by moving a transmission that has been received by an eNB or a UE through one or more layers of a protocol stack.

[0047] Various embodiments of eNBs and/or UEs discussed below may also generate one or more transmissions of various types. Some generating of a transmission may comprise receiving, conducting, and/or otherwise handling a transmission that is to be transmitted. In some embodiments, an eNB or UE generating a transmission may establish the transmission's type and/or a condition associated with the transmission. For some embodiments, an eNB or UE generating a transmission may act in accordance with the transmission's type, and/or may act conditionally based upon the transmission's type. An eNB or UE generating a transmission may also determine one or more values or fields of data carried by the transmission. Generating a transmission may comprise moving the transmission through one or more layers of a protocol stack (which may be implemented in, e.g., hardware and/or software-configured elements), such as by moving a transmission to be sent by an eNB or a UE through one or more layers of a protocol stack.

[0048] Fig. 1 schematically illustrates a UE performing an LBT procedure before

Uplink (UL) transmission, according to some embodiments. In Fig. 1, a traffic stream 100 may comprise various types of UL and DL sub-frames. Fig. 1 may illustrate a traffic stream in a MulteFire™ system, where an eNB may perform cross-burst scheduling of UL sub-frame transmission via an explicit timing relationship. The DL sub-frames in traffic stream 100 are depicted as shaded. Traffic stream 100 may comprise one or more DL sub-frames 102 transmitted from an eNB. The eNB may perform an LBT prior to transmitting DL sub- frames 102, and may reserve the channel for a time period of a first Maximum Channel Occupancy Time (MCOT) 110. If the UE is to transmit one or more UL sub-frames 104 during first MCOT 110, the UE may transmit UL sub-frames 104 without performing an LBT, or with a single short LBT.

[0049] In some embodiments, the eNB may also schedule the UE to transmit UL sub- frames on sub-frames that are not within first MCOT 110 (e.g., the eNB may schedule the UE to transmit during a second MCOT 112 initiated by the UE). Such scheduling may be done, for example, via an explicit timing relationship. Based on such scheduling, the UE may transmit one or more UL sub-frames 106 during MCOT 112. In some embodiments, the UE may perform an LBT procedure (e.g., a Category 4 (Cat 4) LBT) prior to transmitting UL sub-frames 106.

[0050] Fig. 2 schematically illustrates a UE performing an LBT before UL transmission, according to some embodiments. In Fig. 2, a traffic stream 200 may comprise various types of UL and DL sub-frames. Fig. 2 may illustrate a traffic stream 200 in an LAA or eLAA system, where an eNB may perform cross-carrier scheduling of transmission of UL sub-frames via unlicensed spectrum.

[0051] In some embodiments, one or more DL sub-frames 202 may be transmitted over licensed spectrum from a P-cell to the UE. In some embodiments, because the DL sub- frames 202 are transmitted over licensed spectrum, the eNB might not perform any LBT prior to transmitting DL sub-frames 202. [0052] For some embodiments, DL sub-frames 202 may include one or more UL grants (e.g., to schedule transmission of UL sub-frames via unlicensed spectrum). In some embodiments, based on such UL grants, the UE may transmit UL sub-frames 206 during MCOT 210, and/or one or more UL sub-frames 208 during MCOT 212. For some embodiments, UL sub-frames 206 may be transmitted by the UE to an Scell on unlicensed spectrum. Accordingly, prior to the transmission of UL sub-frames 206, the UE may perform an LBT; and prior to the transmission of UL sub-frames 208, the UE may also perform an LBT.

[0053] Fig. 3 schematically illustrates an eNB performing a Cat 4 LBT procedure before DL transmission, according to some embodiments. In Fig. 3, a traffic stream 300 may comprise various types of DL and UL sub-frames transmitted during an MCOT 312. Fig. 3 may illustrate a traffic stream in a MulteFire™ system, and an eNB may perform a Cat 4 LBT 302 prior to transmission during MCOT 312. In some embodiments, PDCCH sub- frames (e.g., depicted as shaded boxes in Fig. 3) may be transmitted in between DL sub- frames. One or more UL sub-frames, short Physical Uplink Control Channel (PUCCH), and/or enhanced PUCCH (ePUCCH) may also be transmitted by a UE to the eNB. For example, the eNB may schedule such Uplink transmissions of the UL sub-frames, short PUCCH, and/or ePUCCH (e.g., by providing UL grant(s) to the UE). If the UE is to transmit one or more UL sub-frames during MCOT 312, the UE may transmit the UL sub-frames without performing an LBT, or with a single short LBT. However, if the UE is to transmit an Uplink sub-frame (e.g., a ePUCCH) outside MCOT 312, the UE may perform a Cat 4 LBT 304 prior to such a transmission.

[0054] Fig. 4 illustrates transmission of one or more UL sub-frames 408, according to some embodiments. In some embodiments, UL sub-frames 408 may comprise any appropriate type of information, such as PUSCH and/or ePUCCH. In some embodiments, UL sub-frames 408 may be transmitted by a UE in an LAA system, by a UE in a MulteFire™ system, or the like. In some embodiments, UL sub-frames 408 may be transmitted during an MCOT 412 over unlicensed spectrum.

[0055] In some embodiments, the UE may perform an LBT procedure (e.g., a Cat 4

LBT) before transmission of UL sub-frames 408, which may facilitate maintenance of fair co-existence with incumbent systems in unlicensed spectrum and with other LAA networks. For example, the UE may perform a Cat 4 LBT by performing a Clear Channel Assessment (CCA) and an exponential back-off procedure in accordance with an algorithm 1 as discussed herein. [0056] In a back-off scheme, a contention window (CW) may be defined. The CW may have boundaries (e.g., a maximum value and a minimum value), and a duration of the Cat 4 LBT may be based on the CW. Table A correlates a priority class of UL sub-frames with various other parameters associated with UL transmission in unlicensed spectrum, according to some embodiments.

Table A

[0057] The first column of Table A lists various channel access priority classes p.

The higher the priority of UL sub-frames, the lower may be the number p. The priority of UL sub-frames may depend on a variety of factors, such as a type of data being transmitted on PUSCH (e.g., whether the data is voice data, video data, time sensitive data, best effort data, background data, etc.), and/or a type of UL sub-frames transmitted (e.g., whether the sub- frames represent PUSCH, Physical Uplink Control Channel (PUCCH), other control data, etc.). In Table A, priority classes p may range from 1 to 4, with 1 having the highest priority and 4 having the lowest priority, although in other examples, the priority class p may have other possible values.

[0058] The second column of Table A lists m_p, which may represent a number of slots in some embodiments, as discussed herein. As an example, slots m_p may be 2 for p having a value of 1 or 2, slots m_p may be 3 for p having a value of 3, and slots m_p may be 7 for p having a value of 4.

[0059] The third column of Table A lists a minimum possible value CWmin,_P for a contention window CWp for the priority class p in some embodiments. The fourth column of Table A lists a maximum possible value CWmax,p for a contention window CW_P for the priority class p in some embodiments. The fifth column of Table A lists a duration of an MCOT UL transmission window (e.g., Tm∞t,p) for the priority class p in some embodiments. The sixth column in Table A lists allowed contention window sizes for the priority class p in some embodiments.

[0060] Accordingly, for a channel access priority class p of 1, the minimum possible contention window size (e.g., CWmin,i) may be 3, the maximum possible contention window size (e.g., CWmax,i) may be 7, the Tm∞t,i may be 2 milliseconds (ms), and the allowed contention window (CWi) sizes may be 3 and 7.

[0061] Referring again to Fig. 4, in some embodiments, the UE may perform the Cat

4 LBT in accordance with algorithm 1. In some embodiments, algorithm 1 may rely on the UE maintaining a counter N for performing the LBT. In some embodiments, as a part of the Cat 4 LBT, the UE may sense a channel in unlicensed spectrum to be idle during the slot durations of a defer duration Td. In some embodiments, the counter N may be adjusted at the UE by sensing the channel for additional slot duration(s) according to algorithm 1.

Algorithm 1 may aim to perform a CCA and an exponential back-off procedure. Algorithm 1 may be explained using a set of six operations which may be performed sequentially (unless an operation conditionally directs to another operation).

[0062] Algorithm 1 may include:

[0063] Operation 1 : set N = Ninit (where Ninit may be a random number uniformly distributed between 0 and CW_P for priority class p, where CW_P is derived from Table A), and go to operation 4;

[0064] Operation 2: if N > 0 and the UE chooses to decrement the counter, then decrement the counter by setting N = N - 1 ;

[0065] Operation 3: sense the channel (e.g., in an unlicensed band that is to be used for the UL transmission) for an additional slot duration. If the channel is idle for the additional slot duration, go to operation 4; else, go to operation 5;

[0066] Operation 4: if N = 0, stop; else, go to operation 2;

[0067] Operation 5: sense the channel until either a busy slot is detected within an additional defer duration Td, or all the slots of the additional defer duration are Td detected to be idle; and

[0068] Operation 6: if the channel is sensed to be idle during the slot durations of the additional defer duration Td, go to operation 4; else, go to operation 5.

[0069] In some embodiments, if algorithm 1 stops at operation 4, this may indicate a successful completion of the Cat 4 LBT, and the UE may transmit UL sub-frames based on the completion of the Cat 4 LBT. (However, as discussed in detail herein, if the Cat 4 LBT is not completed in time for a scheduled transmission of UL sub-frames, or if the Cat 4 LBT is completed ahead of time, the UE may perform additional operations for transmission of the UL sub-frames.) In some embodiments, if the UE has not transmitted a UL transmission including PUSCH on the channel (e.g., the channel on which the LBT is performed) after operation 4 in algorithm 1, the UE may transmit a UL transmission including PUSCH on the channel, after sensing the channel to be idle at least in the slot durations of an additional defer duration Td.

[0070] Operation 3 of algorithm 1 refers to an additional slot duration. In some embodiments, the additional slot duration may be about 9 μβ. In some embodiments, the additional defer duration Td for a priority class p in operation 6 of algorithm 1 may be a function of m_p of Table A. For example, the additional defer duration Td may be a function of (mp * duration of a slot). If the duration of a slot is 9 μβ, then the additional defer duration Td may be a function of (m_P * 9) μβ. In some embodiments, the defer duration Td may comprise or consist of a duration Tf = 16 μβ immediately followed by m_p consecutive slot durations, where each slot duration may be T_si = 9 μβ, and Tf may include an idle slot duration T_si at a start of Tf. For example, for the priority class 4 (e.g., p = 4 in Table A, and mp = 7), the additional defer duration Td may be about (16 + 7 * 9) μβ, e.g., 79 μβ.

[0071] Various operations of algorithm 1 may refer to the channel being idle for one or more slot durations. In some embodiments, a slot duration T_si may be considered to be idle if, for example, the UE senses the channel during the slot duration, and the power detected by the UE for at least 4 μβ within the slot duration is less than an energy detection threshold Xthres. Otherwise, the channel may be considered to be busy.

[0072] As discussed with respect to Table A, for each channel access priority class p, the contention window CW_P can take one of a set of values that are bounded by the maximum and minimum contention window sizes. The contention window CW_P may be used, for example, in operation 1 of algorithm 1. In some embodiments, the contention window CWp may be dynamically selected, and the selection may also be dynamically updated (e.g., as discussed in further detail herein).

[0073] In some embodiments, the UE may initiate the Cat 4 LBT of algorithm 1 , for example, at any instance after detecting a PDCCH or an enhanced PDCCH (ePDCCH) for a corresponding sub-frame. For example, if a PDCCH or an ePDCCH schedules a time for transmitting UL sub-frames (e.g., provides a UL grant, as discussed with respect to Figs. 3- 4), the UE may initiate the Cat 4 LBT of algorithm 1 at any instance after detecting the PDCCH or the ePDCCH comprising the UL grant. [0074] A duration of a Cat 4 LBT may depend on several factors. For example, in operation 1 of algorithm 1, the initial value of the counter N may be selected as Ninit, where Ninit is a random number uniformly distributed between 0 and CW_P. Thus, the duration of the Cat 4 LBT may be based on how large the initial value Ninit of the counter N is. Also, the initial value Ninit is likely to be larger for larger values of CW_P, and CW_P is likely to be larger for larger values of priority class p.

[0075] In another example, the duration of the Cat 4 LBT may be based on a state of the channel. For example, if the channel is idle, the duration of the Cat 4 LBT may be based on decrementing the counter N to zero. However, if the channel is not idle, algorithm 1 may continue in a loop until the channel is idle, thereby resulting in a longer duration of the Cat 4 LBT.

[0076] Fig. 5 illustrates a scenario 500 in which a Cat 4 LBT is completed substantially prior to a start of a scheduled UL transmission (e.g., prior to a threshold period), according to some embodiments. For example, an eNB may schedule a transmission of UL sub-frames starting from a time t3, for a duration of an MCOT 512. The UL scheduling may be indicated via a DL sub-frame 502, which may be a PDCCH sub-frame. (It is to be noted that DL sub-frame 502 may be accompanied by other DL and/or UL sub-frames, although not all such sub-frames are illustrated in Fig. 5.)

[0077] Once the UE detects the UL grant in DL sub-frame 502, the UE may start a

Cat 4 LBT at a time tO. In some embodiments, the Cat 4 LBT may be completed at a time tl, where time tl may be prior (e.g., substantially prior) to the scheduled transmission time t3. For example, time tl may be at least 25 ahead of time t3. In such a situation, the UE may perform a short LBT immediately prior to the start of the scheduled transmission time t3. A short LBT may comprise, for example, a CCA. In some embodiments, the short LBT may comprise a sensing interval T_Short_UL = 25 μβ, which may in turn consist of a duration Tf = 16 μβ, immediately followed by one slot duration of T_si = 9 μβ, for example. In some embodiments, duration Tf may include an idle slot duration T_si at a start of Tf. The channel may be considered to be idle for T_Short_uL if the channel may be sensed to be idle during the slot durations of T_Short_UL. In some embodiments, a short LBT might not involve

decrementing a counter, unlike the Cat 4 LBT discussed with respect to algorithm 1. If the channel is estimated to be idle in the CCA of the short LBT, the UE may transmit UL sub- frames from the scheduled transmission time t3. If, however, the channel is not found to be idle, the UE may continually repeat short LBTs until the channel is estimated to be idle. [0078] Fig. 6 illustrates a scenario 600 in which a Cat 4 LBT is completed immediately prior to a start of a scheduled UL transmission, according to some embodiments. For example, an eNB may schedule a transmission of UL sub-frames starting from a time t6, for a duration of an MCOT 612. The UL scheduling may be indicated via a DL sub-frame 602, which may be a PDCCH sub-frame. Once the UE detects the UL grant in the DL sub- frame 602, the UE may start a Cat 4 LBT at a time t4. In some embodiments, the Cat 4 LBT may be completed at a time t5, where time t5 may be immediately prior to the scheduled transmission time t6. In some embodiments, time t5 may be less than 25 ahead of time t6. In another example, time t5 may be about the same as time t6. In such a situation, the UE may immediately start transmitting the UL sub-frames from the scheduled transmission time t6 after completing the Cat 4 LBT. Thus, unlike Fig. 5, in the embodiments of Fig. 6, the UE might not perform any short LBT before UL transmission.

[0079] Fig. 7 illustrates a scenario 700 in which a Cat 4 LBT is completed

(i) subsequent to a start of a scheduled UL transmission and (ii) before a completion of the scheduled UL transmission, according to some embodiments. For example, in a manner which may be similar to Figs. 5-6, an eNB may schedule a transmission of UL sub-frames starting from a time t8, for a duration of an MCOT 712 (which may be scheduled to last from time t8 to a time tlO). In some embodiments, the scheduling may be for multiple UL sub- frames. The UL scheduling may be indicated via a DL sub-frame 702. Once the UE detects the UL grant in DL sub-frame 702, the UE may start a Cat 4 LBT at a time t7. In some embodiments, the Cat 4 LBT may take a relatively long time (e.g., as compared to scenarios 500 and 600 of Figs. 5-6) and may be completed at a time t9, where the Cat 4 LBT completion time t9 may be after the start of the scheduled transmission time t8. Assuming that the UL grant is for multiple UL sub-frames, the UE may start transmitting the UL sub- frames immediately after completing the Cat 4 LBT at time t9, and may continue transmitting the UL sub-frames until time tlO. In some embodiments, a Hybrid Automatic Repeat Request (HARQ) process due to the relatively long Cat 4 LBT may be dropped.

[0080] Fig. 8 illustrates a scenario 800 in which a Cat 4 LBT is completed subsequent to a start of a scheduled UL transmission and before a completion of the scheduled UL transmission, where a short LBT is performed prior to transmission, according to some embodiments. For example, in a manner which may be similar to Figs. 5-6, an eNB may schedule a transmission of UL sub-frames starting from a time t8', for a duration of an MCOT 812 (e.g., scheduled to last from time t8' to a time tlO'). A first UL sub-frame in MCOT 812 may be scheduled to start from time t8', and a second UL sub-frame in MCOT 812 may be scheduled to start from a time t9'. In some embodiments, the scheduling may be for multiple UL sub-frames. The UL scheduling may be indicated via a DL sub-frame 802. Once the UE detects the UL grant in DL sub-frame 802, the UE may start a Cat 4 LBT at a time t7'. In some embodiments, the Cat 4 LBT may take a relatively long time (e.g., as compared to scenarios 500 and 600 of Figs. 5-6) and may be completed at a time t8a', where the Cat 4 LBT completion time t8a' may be after the start of the scheduled transmission time t8', and before time t9'. Assuming that the UL grant is for multiple UL sub-frames, the UE may start transmitting the UL sub-frames from time t9', and may continue transmitting the UL sub-frames until time tlO'. However, in some embodiments, the UE may perform a short LBT immediately prior to time t9', as illustrated in Fig. 8.

[0081] Fig. 9 illustrates a scenario 900 in which a Cat 4 LBT is not completed during a completion of a scheduled UL transmission and an LBT counter is frozen until a next UL grant is detected, according to some embodiments. For example, in a manner which may be similar to Figs. 5-8, an eNB may schedule a transmission of UL sub-frames starting from a time tl2, for a duration of an MCOT 912 (e.g., scheduled to last from time tl2 to a time tl3). In some embodiments, the scheduling may be for multiple UL sub-frames. The UL scheduling may be indicated via a DL sub-frame 902. Once the UE detects the UL grant in DL sub-frame 902, the UE may start a Cat 4 LBT 901a at a time tl 1. In some embodiments, Cat 4 LBT 901a may take a relatively long time (e.g., as compared to scenarios 500 and 600 of Figs. 5-6) and may not be completed by time tl3 (e.g., it may not be completed before an end of the last scheduled UL sub-frame transmission). In some embodiments, the UE may halt or freeze Cat 4 LBT 901a at time tl3. Thus, Cat 4 LBT 901a may be incomplete (e.g., the counter N may not be decremented to zero yet). In some embodiments, the final counter value, e.g., when Cat 4 LBT 901a is halted, may be Nfreeze. Because Cat 4 LBT 901a may not be completed in time, no sub-frames might be transmitted by the UE during MCOT 912.

[0082] In some embodiments, after time tl3, the eNB may again schedule another transmission of UL sub-frames starting from a time tl6, for a duration of an MCOT 916 (e.g., scheduled to last from time tl6 to a time tl7). The UL scheduling may be indicated via a DL sub-frame 904. Once the UE detects the UL grant in DL sub-frame 904, the UE may start another Cat 4 LBT 901b at a time tl4. However, instead of initializing the counter N to the random starting point Nint for the second Cat 4 LBT 901b (e.g., as discussed with respect to operation 1 of algorithm 1), in some embodiments, the counter N for the second Cat 4 LBT 901b may be initialized to Nfreeze. That is, Cat 4 LBT 901b may be considered as a continuation of Cat 4 LBT 901a, where Cat 4 LBT 901a is frozen or halted from time tl3 to time tl4. Subsequent to the completion of the Cat 4 LBT at a time tl5, the UE may start transmitting the UL sub-frames from time tl6. (However, in some examples, as discussed with respect to Fig. 5, the UE may perform a short LBT after the Cat 4 LBT 901b is finished early, or may have a scenario that is similar to the scenario 700 of Fig. 7.)

[0083] Fig. 10 illustrates a scenario 1000 in which a Cat 4 LBT is not completed during a completion of a scheduled UL transmission and an LBT counter is frozen until an end of UL bursts scheduled for multiple UEs on the considered carrier(s), according to some embodiments. In this scenario, there may be at least two UEs (e.g., a UE 1 and a UE 2) communicating in an unlicensed band. Also, the Cat 4 LBTs illustrated in Fig. 10 may be for UE 1.

[0084] In some embodiments, in a manner which may be similar to Figs. 5-8, an eNB may schedule a transmission of UL sub-frames starting from a time t21, for a duration of an MCOT 1062 (e.g., scheduled to last from time t21 to a time t22), for UL sub-frames by UE 1. In some embodiments, the scheduling may be for multiple UL sub-frames. The UL scheduling may be indicated via a DL sub-frame 1052.

[0085] Also, the eNB may schedule a transmission of UL sub-frames starting from a time t23, for a duration of an MCOT 1064 (e.g., scheduled to last from time t23 to a time t24), for UL sub-frames by UE 2. The UL scheduling may be indicated via a DL sub-frame 1053. Once UE 1 detects the UL grant in DL sub-frame 1052, UE 1 may start a Cat 4 LBT 1051a at a time t20.

[0086] Also, UE 2 may perform a Cat 4 LBT (not illustrated in Fig. 10) for MCOT

1064. Based on whether such a Cat 4 LBT is completed in time, UE 2 may or may not transmit UL sub-frames during MCOT 1064. Time t24 may be assumed to mark an end of UL burst by the UEs in the Scell (e.g., an end of the UL burst by UE 1 and UE 2).

[0087] In some embodiments, Cat 4 LBT 1051a may take a relatively long time (e.g., as compared to scenarios 500 and 600 of Figs. 5-6) and might not be completed by time t22 (e.g., may not be completed until an end of the last scheduled UL sub-frame for UE 1). In some embodiments, UE 1 may continue with Cat 4 LBT 1051a until time t24 or until Cat 4 LBT is successfully completed, whichever occurs earlier. For example, in the embodiment of Fig. 10, Cat 4 LBT 1051a is not completed by time t24, and hence, the UE may halt or freeze Cat 4 LBT 1051a at time t24. Thus, Cat 4 LBT 1051a may be incomplete (e.g., the counter N may not be decremented to zero yet). In some embodiments, the final counter value, e.g., when Cat 4 LBT 1051a is halted, may be assumed to be Nfreezel. Because Cat 4 LBT 1051a might not be completed in time, no sub-frames might be transmitted by UE 1 during MCOT 1062.

[0088] In some embodiments, a DL sub-frame 1054 may provide UL grant to UE 1, e.g., to schedule UL transmission from a time t26 to a time t27 during another MCOT 1066. In some embodiments, UE 1 may restart the incomplete Cat 4 LBT 1051a, e.g., restart as another Cat 4 LBT, for example a Cat 4 LBT 1051b, after receiving the UL grant from DL sub-frame 1054. For example, in some embodiments, the counter N for Cat 4 LBT 1051b may be initialized to Nfreezel. That is, Cat 4 LBT 1051b may be considered as a continuation of Cat 4 LBT 1051a, where Cat 4 LBT 1051a may be frozen or halted from time t22 to time t24. If, for example, Cat 4 LBT 1051b ends substantially prior to time t26, UE 1 may perform a short LBT, e.g., immediate prior to transmitting UL sub-frames from time t26.

[0089] Fig. 11 illustrates a scenario 1100 in which a Cat 4 LBT is completed subsequent to a completion of a scheduled UL transmission and the Cat 4 LBT is not halted, according to some embodiments. In some embodiments, in a manner which may be similar to Figs. 7-9, an eNB may schedule a transmission of UL sub-frames starting from a time t30, for a duration of an MCOT 1112 (e.g., scheduled to last from a time t31 to a time t32). In some embodiments, the scheduling may be for multiple UL sub-frames. The UL scheduling may be indicated via a DL sub-frame 1102.

[0090] Once the UE detects the UL grant in DL sub-frame 1102, the UE may start a

Cat 4 LBT 1101 at time t30 (e.g., the UE may start Cat 4 LBT as soon as the UE detects the UL grant). In some embodiments, Cat 4 LBT 1101 may take a relatively long time (e.g., as compared to scenarios 700 and 800 of Figs. 7-8) and might not be completed by time t32 (e.g., might not be completed until an end of the last scheduled UL sub-frame for the UE). In some embodiments, the UE may continue with Cat 4 LBT 1101 (instead of freezing or halting the LBT, e.g., as discussed with respect to Figs. 10A-10B), and Cat 4 LBT 1101 may complete at a time t33. As illustrated in Fig. 11, the completion of Cat 4 LBT 1101 may be subsequent to the completion of MCOT 1112.

[0091] In some embodiments, when the UE receives a next UL grant from the eNB

(e.g., via a DL sub-frame 1104), the UE may perform a short LBT (e.g., because the UE has already performed Cat 4 LBT 1101), then transmit UL sub-frames from a time t34 to a time 135 during an MCOT 1116.

[0092] In some embodiments, the UE may be configured to operate in accordance with one of scenarios 1000a, 1000b, or 1100 of Figs. 10a, 10b, and 11, respectively. For example, each of these figures may depict a corresponding scenario regarding the actions performed by the UE if the Cat 4 LBT is not completed in time, and the UE may operate in accordance with any one of these figures (e.g., if the Cat 4 LBT is not completed in time).

[0093] In some embodiments, a UE may dynamically adapt an CW_P value for one or more priority classes p. For example, Table A sets forth various allowed CW_P sizes. The UE may dynamically select a CW_P from the allowed CW_P sizes, and may also dynamically change such a selection. The dynamically selected CW_P may be used for operation 1 of algorithm 1 discussed herein.

[0094] In some embodiments, the dynamic selection of CW_P may be based on an algorithm 2. Algorithm 2 may include:

[0095] Operation 1 : for each priority class p e { 1,2,3,4}, set CW_P = CWmin,_P,

[0096] Operation 2: if it is determined that new data indicator (NDI) values corresponding to the HARQ processes in reference sub-frames are not toggled, increase CW_P for each priority class p e { 1,2,3,4} to the next higher allowed value and remain in step 2; otherwise, go to step 1.

[0097] In some embodiments, operation 1 initializes or resets the value of CW_P for a priority class p. Operation 2 refers to NDI values. The NDI values of a reference sub-frame, for example, identify the sub-frame(s) associated with the reference sub-frame. For example, a plurality of continuous sub-frames may be transmitted during a specific UL transmission, and a reference sub-frame may be the first sub-frame or the starting sub-frame of the plurality of continuous sub-frames. If the UL transmission is not successful (e.g., if the eNB is not able to successfully receive and/or decode the received UL sub-frames), the UE may retransmit the same plurality of sub-frames once again (e.g., as a part of the HARQ process). In some embodiments, if a reference UL sub-frame (e.g. a starting sub-frame in a UL burst from the UE) is not detected successfully by the eNB, the NDI of the reference sub-frame may not be toggled and the UE may re-transmit the PUSCH of the reference sub-frame. That is, the NDI value may not be toggled during such HARQ re-transmission. However, if the eNB successfully decodes the received sub-frame(s), new sub-frame(s) may now be transmitted. Thus, two consecutive NDIs may have different values, e.g., may toggle during two consecutive sets of sub-frame transmission.

[0098] In some embodiments, in operation 2 of algorithm 2, the NDI value not toggling implies that there is a sub-frame re-transmission corresponding to the NDI involved in accordance with a HARQ process. Accordingly, if there is a re-transmission of a reference sub-frame, the CW_P may be increased to the next higher allowed value. For example, if the CWp for priority class 3 is currently 63 and there is a re-transmission of reference sub- frame(s) (e.g., the NDI value corresponding to the HARQ processes in reference sub-frames are not toggled), then the new CW_P value may be incremented to 127 (e.g., as indicated in Table A, 127 is the next allowed value for CW_P for priority class 3).

[0099] In some embodiments, a reference sub-frame may be a starting sub-frame of a most recent transmission (e.g., that may be 3 sub-frames before the sub-frame in which the UE received the UL grant) on the same channel made by the UE. For example, Fig. 12A illustrates re-transmission of sub-frames in accordance with a HARQ process in which a reference sub-frame is a starting sub-frame of a most recent transmission (e.g., that may be three sub-frames before the sub-frame in which the UE received the UL grant scheduling the following PUSCH/ePUCCH and for which UE has performed a successful Cat-4 LBT), where the contention window CW_P is dynamically adjusted based on the re-transmission of the reference sub-frames, in accordance with some embodiments. For example, the UE may transmit UL sub-frames UL(1), UL(2), UL(3), and UL(4) during a first UL transmission (e.g., based on performing Cat 4 LBT 1204), and may transmit UL sub-frames UL(5), UL(6), UL(7), and UL(8) during a second UL transmission (e.g., based on performing a Cat 4 LBT 1206), as illustrated in Fig. 12A. The reference sub-frames UL(1) and UL(5) are depicted as shaded in Fig. 12A.

[00100] As also illustrated in Fig. 12A, Uplink sub-frames UL(1), UL(2), UL(3),

UL(4), UL(5), UL(6), UL(7), and UL(8) may be re-transmitted in accordance with a HARQ process, e.g., due to the eNB failing to successfully receive and/or decode these Uplink sub- frames. Such re-transmission, for example, may be indicated in the NDI of the reference sub- frames UL(1) and UL(5). In some embodiments, the UE may receive a feedback 1205 from the eNB indicting that the reference sub-frame UL(1) may need to be re-transmitted. In some embodiments, due to the scheduling of the re-transmission of UL(1), the CWp may be incremented based on feedback 1205, e.g., in accordance with operation 2 of algorithm 2 discussed herein.

[00101] In some embodiments, the UE may receive a feedback 1207 from the eNB indicting that the reference sub-frame UL(5) may need to be re-transmitted. In some embodiments, due to the scheduling of the re-transmission of UL(5), the CW_P may be incremented based on feedback 1207, e.g., in accordance with operation 2 of algorithm 2 discussed herein. Thus, in some embodiments, reference sub-frames are the starting sub- frames of the most recent successful transmissions on the channel made by the UE that are initiated by UE by performing Cat 4 LBT. In an example, only the UL(5) in Fig. 12A may be the reference sub-frame.

[00102] In some embodiments, all UE Uplink sub-frames for HARQ process may also be used as reference sub-frames. For example, Fig. 12B illustrates re-transmission of sub- frames in accordance with a HARQ process in which reference sub-frames are all sub-frames of a most recent transmission, where the contention window CW_P is dynamically adjusted based on the re-transmission of the reference sub-frames, in accordance with some embodiments. For example, the UE may transmit UL sub-frames UL(1), UL(2), UL(3), and UL(4) during a UL transmission (e.g., based on performing a Cat 4 LBT 1210). The references sub-frames UL(1), UL(2), UL(3), and UL(4) are depicted as shaded in Fig. 12B.

[00103] As also illustrated in Fig. 12B, the Uplink sub-frames UL(1), UL(2), UL(3), and UL(4) are re-transmitted in accordance with a HARQ process, e.g., due to the eNB failing to successfully receive or decode these Uplink sub-frames. Such re-transmission, for example, may be indicated in the NDIs of reference sub-frames UL(1), UL(2), UL(3), and UL(4), e.g., during the original transmission and the re-transmission of at least one sub-frame within the reference sub-frames. In some embodiments, due to the re-transmission, the CW_P may be incremented if and after all the reference sub-frames UL(1), UL(2), UL(3), and UL(4) are re-transmitted, e.g., in accordance with algorithm 2 discussed herein. In some embodiments, if all the reference sub-frames (e.g., reference sub-frames UL(1), UL(2), UL(3), and UL(4)) are retransmitted, the CWp may be incremented if and after all the reference sub-frames UL(1), UL(2), UL(3), and UL(4) are re-transmitted, e.g., in accordance with the algorithm 2 discussed herein.

[00104] In some embodiments, reference sub-frames may be the sub-frames of the most recent transmission burst performed with Cat 4 LBT at the UE, e.g., for which feedback is received. For example, Fig. 12C illustrates re-transmission of sub-frames in accordance with a HARQ process in which reference sub-frames of two UL bursts are re-transmitted, where the contention window CW_P is dynamically adjusted based on the re-transmission of the reference sub-frames, in accordance with some embodiments. For example, the UE may transmits UL sub-frames UL(1), UL(2), UL(3), and UL(4) during a first UL transmission (e.g., based on performing a Cat 4 LBT, not illustrated in the figure), and the UE may transmit UL sub-frames UL(5), UL(6), UL(7), and UL(8) during a second UL transmission (e.g., based on performing a Cat 4 LBT, not illustrated in the figure). The references sub- frames UL(1), UL(2), UL(3), UL(4), UL(5), UL(6), UL(7), and UL(8) are depicted as shaded in Fig. 12C [00105] As also illustrated in Fig. 12C, the Uplink sub-frames UL(1), UL(2), UL(3),

UL(4), UL(5), UL(6), UL(7), and UL(8) may be re-transmitted in accordance with a HARQ process, e.g., due to the eNB failing to successfully receive and/or decode these Uplink sub- frames. Such re-transmission, for example, may be indicated in the NDI of the reference sub- frames UL(1), UL(2), UL(3), UL(4), UL(5), UL(6), UL(7), and UL(8), e.g., during the original transmission and the re-transmission. In some embodiments, due to the retransmission, the CWp may be incremented after all the reference sub-frames UL(1), UL(2), UL(3), UL(4), UL(5), UL(6), UL(7), and UL(4) are re-transmitted, and may also be incremented after all the reference sub-frames UL(5), UL(6), UL(7), and UL(8) are retransmitted, e.g., in accordance with algorithm 2 discussed herein.

[00106] In some embodiments, if the CWp is incremented (e.g., as discussed with respect to Figs. 12A-12C), eventually the CWp may reach its maximum possible value for the priority class p. For example, in algorithm 2 discussed herein, if the CWp has not reached the maximum possible value, the CWp may be incremented in accordance with operation 2 of algorithm 2 (e.g., in case of HARQ retransmission). For example, if the CWp reaches its maximum value CWmax,p (e.g., as discussed with respect to Table A), the CW_P the next higher allowed value for CW_P is CWmax,p.

[00107] In some embodiments, an algorithm 3 may guide the adaptation of CW_P once

CWmax,p is reached. Algorithm 3 may include:

[00108] Operation 1 : If the CWp = CWmax,p is consecutively used K times for generation of Ninit of operation 1 of algorithm 1, then CWp may be reset to CWmin,_P only for the priority class p for which CWp = CWmax,p is consecutively used K times for generation of Ninit. Also, the parameter K may be selected by eNB (or by the UE, or by a user) from the set of values {1, 2, ...,8} for each priority class e {1,2,3,4}.

[00109] Thus, algorithm 3 may selectively reset the CWp value from CWmax,p to

CWmin,p for a specific priority class, e.g., if CWmax,p has been used for K consecutive times with priority class p after the CW_P has reached the maximum allowed value. In some embodiments, algorithm 3 may be modified, for example, such that the CWp for all priority classes may be reset at the same time (e.g., based on the CWmax,p being used K times for generation of Ninit for a specific priority class). Although algorithm 3 may provide some example values of the parameter K, other values of K may also be possible.

[00110] In some embodiments, the UE may transmit UL sub-frames in multiple channels in unlicensed spectrum. Such transmission, for example, may be simultaneous or near simultaneous across the multiple channels. Fig. 13 illustrates a table 1300 depicting various exemplary types of operations associated with LBTs performed by a UE while transmitting UL sub-frames across multiple channels, according to some embodiments.

[00111] In some embodiments, C may be a set of channels on which the UE may be scheduled to transmit UL sub-frames, and individual channels may be Ci e C, where i = 0, 1, ... , q-1, q. Thus, there may be a number of channels (q+1) on which the UE may intend to transmit UL sub-frames. As discussed with respect to Figs. 1-2, these channels may be in unlicensed spectrum. In some embodiments, the transmission ending instance may exceed Tm∞t,p after the eNB completes channel access procedure with priority p on channel Ci.

[00112] As illustrated in table 1300, there may be two main types of LBT procedures - type A and type B. In type A, the UE may perform Cat 4 LBT on all channels on which the UE is scheduled to transmit UL sub-frames. Type A may have two sub-types, Al and A2. In some embodiments, the counter N discussed in algorithm 1 may be determined for each channel Ci, and may be denoted as N_Ci. In some embodiments, the contention window for a channel Ci may be denoted as CWd.p.

[00113] In some embodiments, for sub-type Al, the counter N_Ci of each cannel may be independently determined and updated. Also, the contention window CWd.p for each channel may be independently determined and updated. In some embodiments, in sub-type Al, if the absence of any other technology sharing the carrier cannot be guaranteed on a long term basis (e.g., by level of regulation), when the UE ceases transmission on any one channel Ci e C, for each channel Ci≠ q, the UE may resume decrementing Nd when idle slots are detected either after waiting for a duration of 4.T_si, or after re-initializing Nd.

[00114] In some embodiments, for sub-type A2, assume that for channels co, ci, .. . , Ci,

. . . , Cq, the corresponding contention windows have values CWo.p, CWi,_P, ... , CWi,_P, ... , CWq.p for a priority class p. Also, assume that the maximum or largest among these CW values for all the channels is given by CWMax_o_q,p. In some embodiments, in sub-type A2, the counters Nd for all the channels may be initialized based on CWMax_o_q,p for the priority class p. Thus, for any of the channels, operation 1 of algorithm 1 may use the CWMax_o_q,p (e.g., instead of using the contention window for that specific channel).

[00115] For example, assume that Cj is the channel that has the largest contention window value (e.g., the contention window of the channel Cj is CWMax_o_q,p). Thus, for subtype A2, for each channel Ci within the channel set C, Nd = Nd. In some embodiments, for sub-type A2, if the absence of any other technology sharing the carrier cannot be guaranteed on a long-term basis (e.g., by level of regulation), when the UE ceases transmission on any one channel for which Nd is determined, the UE may re-initialize Nd for all channels.

[00116] Referring again to Fig. 13, in type B, a Cat 4 LBT may be performed in a single selected channel, and short LBTs may be performed on other channels by the UE after the Cat-4 LBT may be completed on the single selected channel, e.g., before the UE is to transmit UL sub-frames in the channels. For type B LBT, in some embodiments, the UE may select a channel cj e C as follows:

[00117] Operation 1 : the UE may select Cj by uniformly randomly choosing cj from C before transmission on multiple channels Ci e C, or

[00118] Operation 2: the UE may select channel Cj no more frequently than once every, for example, 1 second.

[00119] Thus, for example, the channel Cj may be selected randomly, and/or the channel Cj may not be selected more frequently than once every threshold time period (which, for example, may be 1 second).

[00120] In some embodiments, in type B, to transmit on the selected channel cj, the UE may perform channel access on the channel q by performing a Cat 4 LBT on this channel.

[00121] In some embodiments, in type B, to transmit on channel Ci (e.g., where Ci≠ Cj, and Ci e C, where q is the selected channel), the UE may perform the following:

[00122] For each channel Ci, the UE may sense the channel Ci for at least a sensing interval Tmc = 25 immediately before the transmitting on channel Cj, and the eNB may transmit on channel Ci immediately after sensing the channel Ci to be idle for at least the sensing interval Tmc. The channel Ci may be considered to be idle for Tmc if the channel is sensed to be idle during all the time durations in which such idle sensing is performed on the channel cj in given interval Tmc.

[00123] Thus, for the selected channel Cj and for type B, the UE may perform the Cat 4

LBT. For each of the non-selected channels (e.g., channels Ci≠ Cj), the UE may perform a corresponding short LBT (e.g., for the duration Tmc, which may be equal to 25 μβ, for example) prior to transmission.

[00124] As illustrated in table 1300, type B may have two sub-types, Bl and B2. For type B, a single or common CW_P value may be maintained for the set of channels C (e.g., instead of maintaining individual CWd.p values for each channel Ci). [00125] In some embodiments, for sub-type Bl, if there is a HARQ re-transmission on any channel, the common CW_P value may be incremented in accordance with operation 2 of algorithm 2. For example, operation 2 of algorithm 2 may be modified as:

[00126] In a modified operation 2 of algorithm 2, if it is determined that NDI values corresponding to the HARQ processes in reference sub-frames are not toggled for all channels Ci e C, the common CW_P for each priority class p e { 1,2,3,4} may be increased to the next higher allowed value and remain in step 2; otherwise, go to step 1.

[00127] In some embodiments, for sub-type B2, a CW_P value may be maintained independently for each channel (e.g., using algorithm 2 and Table A discussed previously herein). For determining the Ninit for channel Cj, the CWp value of channel Cji e C is used, where Cji is the channel with largest CW_P among all channels in the set C. Thus, in sub-type B2, although the CW_P value may be maintained independently for each channel, the largest of the CWp values across all the channels may be used for performing the Cat 4 LBT on the selected channel cj.

[00128] Fig. 14 illustrates an eNB and a UE, according to some embodiments. Fig. 14 includes block diagrams of an eNB 1410 and a UE 1430 which are operable to co-exist with each other and other elements of an LTE network. High-level, simplified architectures of eNB 1410 and UE 1430 are described so as not to obscure the embodiments. It should be noted that in some embodiments, eNB 1410 may be a stationary non-mobile device. In some embodiments, the UE 1430 of Fig. 14 may correspond to any UE discussed herein.

[00129] In some embodiments, the eNB 1410 is coupled to one or more antennas 1405, and UE 1430 is similarly coupled to one or more antennas 1425. However, in some embodiments, eNB 1410 may incorporate or comprise antennas 1405, and UE 1430 in various embodiments may incorporate or comprise antennas 1425.

[00130] In some embodiments, antennas 1405 and/or antennas 1425 may comprise one or more directional or omni-directional antennas, including monopole antennas, dipole antennas, loop antennas, patch antennas, microstrip antennas, coplanar wave antennas, or other types of antennas suitable for transmission of RF signals. In some MIMO (multiple- input and multiple output) embodiments, antennas 1405 are separated to take advantage of spatial diversity.

[00131] eNB 1410 and UE 1430 are operable to communicate with each other on a network, such as a wireless network (e.g., using licensed or unlicensed spectrum). eNB 1410 and UE 1430 may be in communication with each other over a wireless communication channel 1450, which has both a downlink path from eNB 1410 to UE 1430 and an Uplink path from UE 1430 to eNB 1410.

[00132] As illustrated in Fig. 14, in some embodiments, eNB 1410 may include a physical layer circuitry 1412, a MAC (media access control) circuitry 1414, a processor 1416, a memory 1418, and a hardware processing circuitry 1420. A person skilled in the art will appreciate that other components not shown may be used in addition to the components shown to form a complete eNB.

[00133] In some embodiments, physical layer circuitry 1412 includes a transceiver

1413 for providing signals to and from UE 1430. Transceiver 1413 provides signals to and from UEs or other devices using one or more antennas 1405. In some embodiments, MAC circuitry 1414 controls access to the wireless medium. Memory 1418 may be, or may include, a storage media/medium such as a magnetic storage media (e.g., magnetic tapes or magnetic disks), an optical storage media (e.g., optical discs), an electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash-memory-based storage media), or any tangible storage media or non-transitory storage media. Hardware processing circuitry 1420 may comprise logic devices or circuitry to perform various operations. In some embodiments, processor 1416 and memory 1418 are arranged to perform the operations of hardware processing circuitry 1420, such as operations described herein with reference to logic devices and circuitry within eNB 1410 and/or hardware processing circuitry 1420.

[00134] Accordingly, in some embodiments, eNB 1410 may be a device comprising an application processor, a memory, one or more antenna ports, and an interface for allowing the application processor to communicate with another device.

[00135] As is also illustrated in Fig. 14, in some embodiments, UE 1430 may include a physical layer circuitry 1432, a MAC circuitry 1434, a processor 1436, a memory 1438, a hardware processing circuitry 1440, a wireless interface 1442, and a display 1444. A person skilled in the art would appreciate that other components not shown may be used in addition to the components shown to form a complete UE.

[00136] In some embodiments, physical layer circuitry 1432 includes a transceiver

1433 for providing signals to and from eNB 1410 (as well as other eNBs). Transceiver 1433 provides signals to and from eNBs or other devices using one or more antennas 1425. In some embodiments, MAC circuitry 1434 controls access to the wireless medium. Memory 1438 may be, or may include, a storage media/medium such as a magnetic storage media (e.g., magnetic tapes or magnetic disks), an optical storage media (e.g., optical discs), an electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or fiash- memory-based storage media), or any tangible storage media or non-transitory storage media. Wireless interface 1442 may be arranged to allow the processor to communicate with another device. Display 1444 may provide a visual and/or tactile display for a user to interact with UE 1430, such as a touch-screen display. Hardware processing circuitry 1440 may comprise logic devices or circuitry to perform various operations. In some embodiments, processor 1436 and memory 1438 may be arranged to perform the operations of hardware processing circuitry 1440, such as operations described herein with reference to logic devices and circuitry within UE 1430 and/or hardware processing circuitry 1440.

[00137] Accordingly, in some embodiments, UE 1430 may be a device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display.

[00138] Elements of Fig. 14, and elements of other figures having the same names or reference numbers, can operate or function in the manner described herein with respect to any such figures (although the operation and function of such elements is not limited to such descriptions). For example, Figs. 1-2 and 15-16 also depict embodiments of eNBs, hardware processing circuitry of eNBs, UEs, and/or hardware processing circuitry of UEs, and the embodiments described with respect to Fig. 14 and Figs. 1-2 and 15-16 can operate or function in the manner described herein with respect to any of the figures.

[00139] In addition, although eNB 1410 and UE 1430 are each described as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements and/or other hardware elements. In some embodiments of this disclosure, the functional elements can refer to one or more processes operating on one or more processing elements. Examples of software and/or hardware configured elements include Digital Signal Processors (DSPs), one or more microprocessors, DSPs, Field-Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Radio-Frequency Integrated Circuits (RFICs), and so on.

[00140] Fig. 15 illustrates hardware processing circuitries for an eNB that supports a

UE conducting LBTs prior to UL transmission, according to some embodiments. With reference to Fig. 14, an eNB may include various hardware processing circuitries discussed below, which may in turn comprise logic devices and/or circuitry operable to perform various operations. For example, in Fig. 14, eNB 1410 (or various elements or components therein, such as hardware processing circuitry 1420, or combinations of elements or components therein) may include part of, or all of, these hardware processing circuitries. [00141] In some embodiments, one or more devices or circuitries within these hardware processing circuitries may be implemented by combinations of software-configured elements and/or other hardware elements. For example, processor 1416 (and/or one or more other processors which eNB 1410 may comprise), memory 1418, and/or other elements or components of eNB 1410 (which may include hardware processing circuitry 1420) may be arranged to perform the operations of these hardware processing circuitries, such as operations described herein with reference to devices and circuitry within these hardware processing circuitries. In some embodiments, processor 1416 (and/or one or more other processors which eNB 1410 may comprise) may be a baseband processor.

[00142] Returning to Fig. 15, an apparatus of eNB 1410 (or another eNB or base station), which may be operable to communicate with one or more UEs on a wireless network, may comprise hardware processing circuitry 1500. In some embodiments, hardware processing circuitry 1500 may comprise one or more antenna ports 1505 operable to provide various transmissions over a wireless communication channel (such as wireless

communication channel 1450). Antenna ports 1505 may be coupled to one or more antennas 1507 (which may be antennas 1405). In some embodiments, hardware processing circuitry 1500 may incorporate antennas 1507, while in other embodiments, hardware processing circuitry 1500 may merely be coupled to antennas 1507.

[00143] Antenna ports 1505 and antennas 1507 may be operable to provide signals from an eNB to a wireless communications channel and/or a UE, and may be operable to provide signals from a UE and/or a wireless communications channel to an eNB. For example, antenna ports 1505 and antennas 1507 may be operable to provide transmissions from eNB 1410 to wireless communication channel 1450 (and from there to UE 1430, or to another UE). Similarly, antennas 1507 and antenna ports 1505 may be operable to provide transmissions from a wireless communication channel 1450 (and beyond that, from UE 1430, or another UE) to eNB 1410.

[00144] Hardware processing circuitry 1500 may comprise various circuitries operable in accordance with the various embodiments discussed herein. With reference to Fig. 15, hardware processing circuitry 1500 may comprise a first circuitry 1510, a second circuitry 1520, and a third circuitry 1530.

[00145] First circuitry 1510 may be operable to schedule a plurality of sub-frames for the UE for UL transmission. Second circuitry 1520 may be operable to determine the sub- frames used by the UE for UL transmission. Second circuitry 1520 may provide the received sub-frames to third circuitry 1530 via an interface 1534. Third circuitry 1530 may decode the received UL sub-frames and process the UL sub-frames.

[00146] In some embodiments, hardware processing circuitry 1500 may be coupled to a transceiver circuitry for at least one of: generating transmissions, scheduling UL transmissions, encoding transmissions, processing transmissions, or decoding transmissions.

[00147] In some embodiments, first circuitry 1510, second circuitry 1520, and/or third circuitry 1530 may be implemented as separate circuitries. In other embodiments, first circuitry 1510, second circuitry 1520, and/or third circuitry 1530 may be combined and implemented together in a circuitry without altering the essence of the embodiments.

[00148] Fig. 16 illustrates hardware processing circuitries for a UE for performing

LBT prior to UL transmission in unlicensed spectrum, according to some embodiments. With reference to Fig. 14, a UE may include various hardware processing circuitries discussed below, which may in rum comprise logic devices and/or circuitry operable to perform various operations. For example, in Fig. 14, UE 1430 (or various elements or components therein, such as hardware processing circuitry 1440, or combinations of elements or components therein) may include part of, or all of, these hardware processing circuitries.

[00149] In some embodiments, one or more devices or circuitries within these hardware processing circuitries may be implemented by combinations of software-configured elements and/or other hardware elements. For example, processor 1436 (and/or one or more other processors which UE 1430 may comprise), memory 1438, and/or other elements or components of UE 1430 (which may include hardware processing circuitry 1440) may be arranged to perform the operations of these hardware processing circuitries, such as operations described herein with reference to devices and circuitry within these hardware processing circuitries. In some embodiments, processor 1436 (and/or one or more other processors which UE 1430 may comprise) may be a baseband processor.

[00150] Returning to Fig. 16, an apparatus of UE 1430 (or another UE or mobile handset), which may be operable to communicate with one or more eNBs on a wireless network, may comprise hardware processing circuitry 1600. In some embodiments, hardware processing circuitry 1600 may comprise one or more antenna ports 1605 operable to provide various transmissions over a wireless communication channel (such as wireless

communication channel 1450). Antenna ports 1605 may be coupled to one or more antennas 1607 (which may be antennas 1425). In some embodiments, hardware processing circuitry 1600 may incorporate antennas 1607, while in other embodiments, hardware processing circuitry 1600 may merely be coupled to antennas 1607. [00151] Antenna ports 1605 and antennas 1607 may be operable to provide signals from a UE to a wireless communications channel and/or an eNB, and may be operable to provide signals from an eNB and/or a wireless communications channel to a UE. For example, antenna ports 1605 and antennas 1607 may be operable to provide transmissions from UE 1430 to wireless communication channel 1450 (and from there to eNB 1410, or to another eNB). Similarly, antennas 1607 and antenna ports 1605 may be operable to provide transmissions from a wireless communication channel 1450 (and beyond that, from eNB 1410, or another eNB) to UE 1430.

[00152] Hardware processing circuitry 1600 may comprise various circuitries operable in accordance with the various embodiments discussed herein. With reference to Fig. 16, hardware processing circuitry 1600 may comprise a first circuitry 1610, a second circuitry 1620, and/or a third circuitry 1630. In some embodiments, first circuitry 1610 may be operable to process a UL grant (e.g., from an eNB) to transmit UL sub-frames between a start time and an end time on a channel in an unlicensed spectrum. Second circuitry 1620 may be operable to, prior to transmission of one or more UL sub-frames, conduct a first LBT procedure (e.g., a Cat 4 LBT procedure). Third circuitry 1630 may be operable to, in response to a completion of the first LBT procedure prior to the end time, transmit one or more UL sub-frames. In some embodiments, the third circuitry 1630 may comprise a transmitter (e.g., comprising components for transmission of UL sub-frames).

[00153] In some embodiments, in response to the completion of the first LBT procedure substantially prior to the start time, the second circuitry 1620 may be operable to perform a short LBT prior to the start time; and the third circuitry 1630 may be operable to, in response to the completion of the Cat 4 LBT and a completion of the short LBT prior to the start time, transmit the one or more UL sub-frames from the start time to the end time.

[00154] In some embodiments, in response to a completion of the first LBT procedure within a threshold duration from the start time, the second circuitry 1620 may be operable to transmit the one or more UL sub-frames from the start time to the end time, without performing any short LBT prior to the transmission of the one or more UL sub-frames.

[00155] In some embodiments, the second circuitry 1620 may perform a short LBT, in response to the completion of the first LBT procedure (which, for example, may be a Cat 4 LBT) subsequent to the start time and prior to the end time; and the third circuitry 1630 may be operable to transmit at least one UL sub-frame, in response to the completion of the short LBT prior to the end time. [00156] In some embodiments, the UL grant may be a first UL grant, the start time may be a first start time, and the end time may be a first end time, and the first circuitry 1610 may be operable to process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum, and the second circuitry 1620 may be operable to initiate a second LBT procedure, in response to the second UL grant; and halt the second LBT procedure at the second end time, in response to the second LBT procedure not completing prior to the second end time. For example, the second circuitry 1620 may be operable to perform the second LBT procedure by decrementing a first counter, where the first counter may have a first value when the second LBT procedure is halted at the second end time; and store the first value of the first counter, in response to the second LBT procedure not completing prior to the second end time.

[00157] In some embodiments, the UL grant may be a first UL grant, the start time may be a first start time, and the end time may be a first end time, and the first circuitry 1610 may be operable to process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum, where the second UL grant may be associated with a UL burst on the channel by multiple UEs, and where the UL burst is scheduled to end at a UL burst end time. In some embodiments, the second circuitry 1620 may be operable to initiate a second LBT procedure, in response to the second UL grant; and halt the second LBT procedure at the UL burst end time, in response to the second LBT procedure not completing prior to the UL burst end time.

[00158] In some embodiments, the UL grant may be a first UL grant, the start time may be a first start time, and the end time may be a first end time, and the first circuitry 1610 may be operable to process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum. In some embodiments, the second circuitry 1620 may be operable to initiate a second LBT procedure, in response to the second UL grant; and continue the second LBT procedure beyond the second end time such that the second LBT procedure is completed after the second end time, in response to the second LBT procedure not completing prior to the first end time.

[00159] In some embodiments, if the UE is to transmit in multiple unlicensed channels, the second circuitry 1620 may be operable to, prior to transmission of one or more UL sub- frames, conduct a Cat 4 LBT in one channel and conduct short LBTs in other channels (e.g., as discussed with respect to type B of table 1300 of Fig. 13). In some other embodiments, if the UE is to transmit in multiple unlicensed channels, the second circuitry 1620 may be operable to, prior to transmission of one or more UL sub-frames, conduct Cat 4 LBTs on all the channels in an unlicensed band in which the UE is to transmit (e.g., as discussed with respect to type A of table 1300 of Fig. 13).

[00160] In some embodiments, the second circuitry 1620 may also be operable to adaptively update a contention window size. Merely as an example, the second circuitry 1620 may also be operable to select a contention window size, and dynamically update the contention window size if, for example, the re-transmits one or more UL sub-frames in accordance with the HARQ process (e.g., as discussed with respect to algorithm 2).

[00161] In some embodiments, first circuitry 1610, second circuitry 1620, and/or third circuitry 1630 may be implemented as separate circuitries. In other embodiments, first circuitry 1610, second circuitry 1620, and third circuitry 1630 may be combined and implemented together in a circuitry without altering the essence of the embodiments.

[00162] Fig. 17 illustrates methods for a UE for performing Cat 4 LBT prior to transmitting UL sub-frames in a channel in the unlicensed spectrum, according to some embodiments. With reference to Fig. 14, methods that may relate to UE 1430 and hardware processing circuitry 1440 are discussed below. Although the actions in the method of Fig. 17 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions may be performed in parallel. Some of the actions and/or operations listed in Fig. 17 are optional in accordance with certain embodiments. The numbering of the actions presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various actions must occur. Additionally, operations from the various flows may be utilized in a variety of combinations.

[00163] Moreover, in some embodiments, machine readable storage media may have executable instructions that, when executed, cause UE 1430 and/or hardware processing circuitry 1440 to perform an operation comprising the method of Fig. 17. Such machine readable storage media may include any of a variety of storage media, like magnetic storage media (e.g., magnetic tapes or magnetic disks), optical storage media (e.g., optical discs), electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash- memory-based storage media), or any other tangible storage media or non-transitory storage media.

[00164] In some embodiments, an apparatus may comprise means for performing various actions and/or operations of the methods 1700 of Fig. 17.

[00165] Returning to Fig. 17, various methods may be in accordance with the various embodiments discussed herein. A method 1700 may comprise, at 1704, receiving a UL grant to transmit UL sub-frames between a start time and an end time on a channel in an unlicensed spectrum. At 1708, a Cat 4 LBT procedure may be performed. At 1712, it is determined whether the Cat 4 LBT is completed prior to the start time.

[00166] If the Cat 4 LBT is completed prior to the start time (e.g., "Yes" at 1712), one of the two operations of 1716 may be performed. For example, in the operation "A" at 1716, in response to the completion of the Cat 4 LBT procedure substantially prior to the start time, (i) a short LBT may be performed prior to the start time, and (ii) one or more UL sub-frames may be transmitted from the start time to the end time, e.g., as discussed with respect to Fig. 7. In another example, in the operation "B" at 1716, in response to a completion of the Cat 4 LBT procedure within a threshold duration from the start time, one or more UL sub-frames may be transmitted from the start time to the end time, without performing any short LBT prior to the transmission of the one or more UL sub-frames, e.g., as discussed with respect to Fig. 8.

[00167] If the Cat 4 LBT is not completed prior to the start time (e.g., "No" at 1712), then at 1720 it is determined if the Cat 4 LBT is completed prior to the end time. If the Cat 4 LBT is completed prior to the end time (e.g., "Yes" at 1720), then at 1724, one or more UL sub-frames may be transmitted from the end of the Cat 4 LBT to the end time, e.g., as discussed with respect to Fig. 9.

[00168] If the Cat 4 LBT is not completed prior to the end time (e.g., "No" at 1720), then at 1728, one of the two operations of 1728 may be performed. For example, in the operation "A" at 1728, the Cat 4 LBT may be halted at the end time, the last value of the counter associated with the Cat 4 LBT may be stored, and the last value of the counter may be used for a next Cat 4 LBT, e.g., as discussed with respect to Figs. 10A-10B. In another example, in the operation "B" at 1728, the Cat 4 LBT may be continued and finished, e.g., as discussed with respect to Fig. 11.

[00169] Fig. 18 illustrates methods for a UE for dynamically updating a contention window size, according to some embodiments. With reference to Fig. 14, methods that may relate to UE 1430 and hardware processing circuitry 1440 are discussed below. Although the actions in the method of Fig. 18 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions may be performed in parallel. Some of the actions and/or operations listed in Fig. 18 are optional in accordance with certain embodiments. The numbering of the actions presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various actions must occur. Additionally, operations from the various flows may be utilized in a variety of combinations.

[00170] Moreover, in some embodiments, machine readable storage media may have executable instructions that, when executed, cause UE 1430 and/or hardware processing circuitry 1440 to perform an operation comprising the method of Fig. 18. Such machine readable storage media may include any of a variety of storage media, like magnetic storage media (e.g., magnetic tapes or magnetic disks), optical storage media (e.g., optical discs), electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash- memory-based storage media), or any other tangible storage media or non-transitory storage media.

[00171] In some embodiments, an apparatus may comprise means for performing various actions and/or operations of the methods 1800 of Fig. 18.

[00172] Returning to Fig. 18, various methods may be in accordance with the various embodiments discussed herein. A method 1800 may comprise, at 1804, selecting a first value for a contention window, e.g., for a specific priority class p (e.g., selecting a value from the allowed sizes for a contention window CW_P from Table A). At 1808, a Cat 4 LBT may be performed, e.g., based at least in part on the first value of the contention window, e.g., as discussed with respect to the operation 1 of algorithm 1.

[00173] At 1812, upon successful completion of the Cat 4 LBT, a plurality of UL sub- frames may be transmitted by the UE, e.g., based at least in part on a completion of the Cat 4 LBT within a scheduled duration. In some embodiments, one or more of the plurality of UL sub-frames may be classified as reference sub-frames. In some embodiments, the reference sub-frames may be the starting sub-frames of a most recent successful transmissions on a channel made by the UE that are initiated by UE by performing the Cat 4 LBT.

[00174] In some embodiments, a request from the eNB to re-transmit the reference sub-frames in accordance with a HARQ process may be processed. At 1816, one or more UL sub-frames (e.g., at least the reference sub-frames) may be re-transmitted in accordance with the HARQ process, e.g., as discussed with respect to Figs. 12A-12C. At 1820, in response to re-transmitting the one or more UL sub-frames in accordance with the HARQ process, a second value for the contention window may be selected, e.g., as discussed with respect to algorithm 2 discussed herein. In some embodiments, the second value for the contention window may be a next higher allowed value for the contention window after the first value of a first priority class. [00175] In some embodiments, the second value for the contention window may be a maximum allowed value for the contention window size of the first priority class. In some embodiments and although not illustrated in the Fig. 18, subsequent to selecting second value for the contention window, UL re-transmissions of the reference sub-frames may be performed in accordance with the HARQ process for at least a threshold number of times. A third value for the contention window may be selected, in response to performing the UL retransmissions of the reference sub-frames in accordance with the HARQ process for at least the threshold number of times. In some embodiments, the third value for the contention window may be a minimum allowed value for the contention window for the first priority class for which the reference sub-frames have been re-transmitted for at least the threshold number of times.

[00176] Fig. 19 illustrates methods for a UE for selectively conducting LBTs on multiple channels in the unlicensed spectrum, in accordance with some embodiments. With reference to Fig. 14, methods that may relate to UE 1430 and hardware processing circuitry 1440 are discussed below. Although the actions in the method of Fig. 19 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions may be performed in parallel. Some of the actions and/or operations listed in Fig. 19 are optional in accordance with certain embodiments. The numbering of the actions presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various actions must

occur. Additionally, operations from the various flows may be utilized in a variety of combinations.

[00177] Moreover, in some embodiments, machine readable storage media may have executable instructions that, when executed, cause UE 1430 and/or hardware processing circuitry 1440 to perform an operation comprising the method of Fig. 19. Such machine readable storage media may include any of a variety of storage media, like magnetic storage media (e.g., magnetic tapes or magnetic disks), optical storage media (e.g., optical discs), electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash- memory-based storage media), or any other tangible storage media or non-transitory storage media.

[00178] In some embodiments, an apparatus may comprise means for performing various actions and/or operations of the methods 1900 of Fig. 19.

[00179] Returning to Fig. 19, various methods may be in accordance with the various embodiments discussed herein. A method 1900 may comprise, at 1904, receiving a UL grant to transmit UL sub-frames on at least a first channel and a second channel in an unlicensed spectrum. At 1908, the first channel may be selected from among the first and second channels. The selection, in some embodiments, may be random. In another example, the selection may ensure that the first channel is not selected more than once during a threshold time period.

[00180] At 1912, a Cat 4 LBT may be performed on the selected first channel. Upon the Cat 4 LBT being successful, a short LBT may then be performed on the second channel. Thus, the method 1900 may correspond to type B of table 1300 of Fig. 13. In some embodiments, UL sub-frames may be transmitted on the first channel based on the successful completion of the Cat 4 LBT, and UL sub-frames may be transmitted on the second channel based on the successful completion of the short LBT. In some embodiments, one or more first UL sub-frames may be transmitted on the first channel, in response to a completion of the Cat 4 LBT procedure on the first channel, and one or more second UL sub-frames may be transmitted on the second channel, in response to a completion of the short LBT procedure on the second channel.

[00181] Fig. 20 illustrates methods for a UE for selectively conducting independent

Cat 4 LBTs on multiple channels in the unlicensed spectrum, in accordance with some embodiments. With reference to Fig. 14, methods that may relate to UE 1430 and hardware processing circuitry 1440 are discussed below. Although the actions in the method of Fig. 20 are shown in a particular order, the order of the actions can be modified. Thus, the illustrated embodiments can be performed in a different order, and some actions may be performed in parallel. Some of the actions and/or operations listed in Fig. 20 are optional in accordance with certain embodiments. The numbering of the actions presented is for the sake of clarity and is not intended to prescribe an order of operations in which the various actions must occur. Additionally, operations from the various flows may be utilized in a variety of combinations.

[00182] Moreover, in some embodiments, machine readable storage media may have executable instructions that, when executed, cause UE 1430 and/or hardware processing circuitry 1440 to perform an operation comprising the method of Fig. 20. Such machine readable storage media may include any of a variety of storage media, like magnetic storage media (e.g., magnetic tapes or magnetic disks), optical storage media (e.g., optical discs), electronic storage media (e.g., conventional hard disk drives, solid-state disk drives, or flash- memory-based storage media), or any other tangible storage media or non-transitory storage media. [00183] In some embodiments, an apparatus may comprise means for performing various actions and/or operations of the methods 2000 of Fig. 20.

[00184] Returning to Fig. 20, various methods may be in accordance with the various embodiments discussed herein. A method 2000 may comprise, at 2004, receiving a UL grant to transmit UL sub-frames on at least a first channel and a second channel in an unlicensed spectrum. At 2008, a first Cat 4 LBT may be performed on the first channel, and a second Cat 4 LBT may be performed on the second channel. Thus, the method 2000 may correspond to type A of table 1300 of Fig. 13. In some embodiments, UL sub-frames may be transmitted on the first channel based on the successful completion of the first Cat 4 LBT, and UL sub- frames may be transmitted on the second channel based on the successful completion of the second Cat 4 LBT. In some embodiments, one or more first UL sub-frames may be transmitted on the first channel, in response to a completion of the first Cat 4 LBT procedure on the first channel, and one or more second UL sub-frames may be transmitted on the second channel, in response to a completion of the second Cat 4 LBT procedure on the second channel.

[00185] In some embodiments, (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel may be maintained and dynamically updated. The first contention window value may be used to conduct the first Cat 4 LBT procedure on the first channel, and the second contention window value may be used to conduct the second Cat 4 LBT procedure on the second channel.

[00186] In some embodiments, (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel may be maintained and dynamically updated. In some embodiments, a largest contention window value from among the first contention window value and the second contention window value may be selected for the priority class corresponding to the UL transmission. In some embodiments, the largest contention window value may be used to conduct the first Cat 4 LBT procedure on the first channel and the second Cat 4 LBT procedure on the second channel.

[00187] Fig. 21 illustrates example components of a UE device 2100, according to some embodiments. In some embodiments, a UE device 2100 may include application circuitry 2102, baseband circuitry 2104, Radio Frequency (RF) circuitry 2106, front-end module (FEM) circuitry 2108, a low-power wake-up receiver (LP-WUR), and one or more antennas 2110, coupled together at least as shown. In some embodiments, the UE device 2100 may include additional elements such as, for example, memory /storage, display, camera, sensor, and/or input/output (I/O) interface. [00188] The application circuitry 2102 may include one or more application processors. For example, the application circuitry 2102 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with and/or may include memory /storage and may be configured to execute instructions stored in the memory /storage to enable various applications and/or operating systems to run on the system.

[00189] The baseband circuitry 2104 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 2104 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 2106 and to generate baseband signals for a transmit signal path of the RF circuitry 2106. Baseband processing circuity 2104 may interface with the application circuitry 2102 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 2106. For example, in some embodiments, the baseband circuitry 2104 may include a second generation (2G) baseband processor 2104A, third generation (3G) baseband processor 2104B, fourth generation (4G) baseband processor 2104C, and/or other baseband processor(s) 2104D for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 2104 (e.g., one or more of baseband processors 2104A-D) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 2106. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 2104 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 2104 may include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[00190] In some embodiments, the baseband circuitry 2104 may include elements of a protocol stack such as, for example, elements of an EUTRAN protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or RRC elements. A central processing unit (CPU) 2104E of the baseband circuitry 2104 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some

embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 2104F. The audio DSP(s) 2104F may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 2104 and the application circuitry 2102 may be implemented together such as, for example, on a system on a chip (SOC).

[00191] In some embodiments, the baseband circuitry 2104 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 2104 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 2104 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[00192] RF circuitry 2106 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 2106 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 2106 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 2108 and provide baseband signals to the baseband circuitry 2104. RF circuitry 2106 may also include a transmit signal path which may include circuitry to up- convert baseband signals provided by the baseband circuitry 2104 and provide RF output signals to the FEM circuitry 2108 for transmission.

[00193] In some embodiments, the RF circuitry 2106 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 2106 may include mixer circuitry 2106 A, amplifier circuitry 2106B and filter circuitry 2106C. The transmit signal path of the RF circuitry 2106 may include filter circuitry 2106C and mixer circuitry 2106 A. RF circuitry 2106 may also include synthesizer circuitry 2106D for synthesizing a frequency for use by the mixer circuitry 2106A of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 2106A of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 2108 based on the synthesized frequency provided by synthesizer circuitry 2106D. The amplifier circuitry 2106B may be configured to amplify the down-converted signals and the filter circuitry 2106C may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 2104 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 2106A of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[00194] In some embodiments, the mixer circuitry 2106A of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 2106D to generate RF output signals for the FEM circuitry 2108. The baseband signals may be provided by the baseband circuitry 2104 and may be filtered by filter circuitry 2106C. The filter circuitry 2106C may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[00195] In some embodiments, the mixer circuitry 2106A of the receive signal path and the mixer circuitry 2106A of the transmit signal path may include two or more mixers and may be arranged for quadrature down-conversion and/or up-conversion respectively. In some embodiments, the mixer circuitry 2106A of the receive signal path and the mixer circuitry 2106A of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 2106 A of the receive signal path and the mixer circuitry 2106 A may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuitry 2106 A of the receive signal path and the mixer circuitry 2106A of the transmit signal path may be configured for super-heterodyne operation.

[00196] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 2106 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 2104 may include a digital baseband interface to communicate with the RF circuitry 2106. [00197] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[00198] In some embodiments, the synthesizer circuitry 2106D may be a fractional -N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 2106D may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[00199] The synthesizer circuitry 2106D may be configured to synthesize an output frequency for use by the mixer circuitry 2106A of the RF circuitry 2106 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 2106D may be a fractional N/N+l synthesizer.

[00200] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 2104 or the applications processor 2102 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 2102.

[00201] Synthesizer circuitry 2106D of the RF circuitry 2106 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[00202] In some embodiments, synthesizer circuitry 2106D may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 2106 may include an IQ/polar converter.

[00203] FEM circuitry 2108 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 21 10, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 2106 for further processing. FEM circuitry 2108 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 2106 for transmission by one or more of the one or more antennas 21 10.

[00204] In some embodiments, the FEM circuitry 2108 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 2106). The transmit signal path of the FEM circuitry 2108 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 2106), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 21 10.

[00205] In some embodiments, the UE 2100 comprises a plurality of power saving mechanisms. If the UE 2100 is in an RRC_Connected state, where it is still connected to the eNB as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device may power down for brief intervals of time and thus save power.

[00206] If there is no data traffic activity for an extended period of time, then the UE

2100 may transition off to an RRC Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The UE 2100 goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. Since the device might not receive data in this state, in order to receive data, it should transition back to RRC Connected state.

[00207] An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable. [00208] In addition, in various embodiments, an eNB device may include components substantially similar to one or more of the example components of UE device 2100 described herein.

[00209] Reference in the specification to "an embodiment," "one embodiment," "some embodiments," or "other embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments. The various appearances of "an embodiment," "one embodiment," or "some embodiments" are not necessarily all referring to the same embodiments. If the specification states a component, feature, structure, or characteristic "may," "might," or "could" be included, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to "a" or "an" element, that does not mean there is only one of the elements. If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element.

[00210] Furthermore, the particular features, structures, functions, or characteristics may be combined in any suitable manner in one or more embodiments. For example, a first embodiment may be combined with a second embodiment anywhere the particular features, structures, functions, or characteristics associated with the two embodiments are not mutually exclusive.

[00211] While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of such embodiments will be apparent to those of ordinary skill in the art in light of the foregoing description. For example, other memory architectures e.g., Dynamic RAM (DRAM) may use the

embodiments discussed. The embodiments of the disclosure are intended to embrace all such alternatives, modifications, and variations as to fall within the broad scope of the appended claims.

[00212] In addition, well known power/ground connections to integrated circuit (IC) chips and other components may or may not be shown within the presented figures, for simplicity of illustration and discussion, and so as not to obscure the disclosure. Further, arrangements may be shown in block diagram form in order to avoid obscuring the disclosure, and also in view of the fact that specifics with respect to implementation of such block diagram arrangements are highly dependent upon the platform within which the present disclosure is to be implemented (i.e., such specifics should be well within purview of one skilled in the art). Where specific details (e.g., circuits) are set forth in order to describe example embodiments of the disclosure, it should be apparent to one skilled in the art that the disclosure can be practiced without, or with variation of, these specific details. The description is thus to be regarded as illustrative instead of limiting.

[00213] The following clauses pertain to further embodiments. Specifics in the clauses may be used anywhere in one or more embodiments. All optional features of the apparatus described herein may also be implemented with respect to a method or process.

[00214] Clause 1. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising: a memory for storing instructions; and one or more processors to: process an Uplink (UL) grant to transmit UL sub-frames between a start time and an end time on a channel in an unlicensed spectrum; conduct a Listen-Before-Talk (LBT) procedure subsequent to processing the UL grant; and initiate transmission of one or more UL sub-frames, in response to a completion of the LBT procedure prior to the end time.

[00215] Clause 2. The apparatus of clause 1, wherein the LBT is a category 4 (Cat 4)

LBT, and wherein the one or more processors are to: perform a short LBT prior to the start time, in response to the completion of the Cat 4 LBT procedure substantially prior to the start time; and initiate transmission of the one or more UL sub-frames from the start time to the end time, in response to the completion of the Cat 4 LBT and a completion of the short LBT prior to the start time.

[00216] Clause 3. The apparatus of clause 1, wherein the LBT is a category 4 (Cat 4)

LBT, and wherein the one or more processors are to: perform a short LBT, in response to the completion of the Cat 4 LBT procedure subsequent to the start time and prior to the end time; and initiate transmission of at least one UL sub-frame, in response to the completion of the short LBT prior to the end time.

[00217] Clause 4. The apparatus of clause 1, wherein the LBT is a category 4 (Cat 4)

LBT, and wherein the one or more processors are to: initiate transmission of the one or more UL sub-frames from the start time to the end time, in response to the completion of the Cat 4 LBT procedure within a threshold duration from the start time, and without performing a short LBT prior to the transmission of the one or more UL sub-frames.

[00218] Clause 5. The apparatus of any of clauses 1 through 3, wherein the LBT is a first LBT, the UL grant is a first UL grant, the start time is a first start time, and the end time is a first end time, and wherein the one or more processors are to: process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum; initiate a second LBT procedure, in response to the second UL grant; and halt the second LBT procedure at the second end time, in response to the second LBT procedure not completing prior to the second end time.

[00219] Clause 6. The apparatus of clause 5, wherein the one or more processors are to: perform the second LBT procedure by decrementing a first counter, wherein the first counter has a first value when the second LBT procedure is halted at the second end time; and store the first value of the first counter, in response to the second LBT procedure not completing prior to the second end time.

[00220] Clause 7. The apparatus of clause 6, wherein the one or more processors are to: process a third UL grant to transmit UL sub-frames between a third start time and a third end time on the channel in the unlicensed spectrum; and initiate a third LBT procedure in response to the third UL grant, wherein a second counter associated with the third LBT procedure is initialized to the first value of the first counter.

[00221] Clause 8. The apparatus of any of clauses 1 through 3, wherein the LBT is a first LBT, the UL grant is a first UL grant, the start time is a first start time, and the end time is a first end time, and wherein the one or more processors are to: process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum, wherein the second UL grant is associated with a UL burst on the channel by multiple UEs, and wherein the UL burst is scheduled to end at a UL burst end time; initiate a second LBT procedure, in response to the second UL grant; and halt the second LBT procedure at the UL burst end time, in response to the second LBT procedure not completing prior to the UL burst end time.

[00222] Clause 9. The apparatus of any of clauses 1 through 3, wherein the LBT is a first LBT, the UL grant is a first UL grant, the start time is a first start time, and the end time is a first end time, and wherein the one or more processors are to: process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum; initiate a second LBT procedure, in response to the second UL grant; and continue the second LBT procedure beyond the second end time such that the second LBT procedure is completed after the second end time, in response to the second LBT procedure not completing prior to the first end time.

[00223] Clause 10. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of clauses 1 through 9. [00224] Clause 11. The apparatus of any of clauses 1 through 10, comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00225] Clause 12. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising: process an Uplink (UL) grant to transmit UL sub-frames between a start time and an end time on a channel in an unlicensed spectrum; conduct a category 4 (Cat 4) Listen-Before-Talk (LBT) procedure, in response to the UL grant; and initiate transmission of one or more UL sub-frames, in response to a completion of the Cat 4 LBT procedure prior to the end time.

[00226] Clause 13. The machine readable storage media of clause 12, the operation comprising: perform a short LBT prior to transmitting the one or more UL sub-frames from the start time to the end time, in response to the completion of the Cat 4 LBT procedure substantially prior to the start time.

[00227] Clause 14. The machine readable storage media of clause 12, the operation comprising: initiate transmission of the one or more UL sub-frames from the start time to the end time, without performing a short LBT prior to the transmission of the one or more UL sub-frames, in response to a completion of the Cat 4 LBT procedure within a threshold duration from the start time.

[00228] Clause 15. The machine readable storage media of any of clauses 12 through

14, wherein the UL grant is a first UL grant, the start time is a first start time, the end time is a first end time, the operation comprising: process a second UL grant to transmit UL sub- frames between a second start time and a second end time on the channel in the unlicensed spectrum; in response to the second UL grant, initiate a second LBT procedure; and in response to the second LBT procedure not completing prior to the end time, halt the second LBT procedure at the second end time.

[00229] Clause 16. The machine readable storage media of clause 15, the operation comprising: perform the second LBT procedure by decrementing a first counter, wherein the first counter has a first value when the second LBT procedure is halted at the second end time; process a third UL grant to transmit UL sub-frames between a third start time and a third end time on the channel in the unlicensed spectrum; and in response to the third UL grant, initiate a third LBT procedure, wherein a second counter associated with the third LBT procedure is initialized to the first value of the first counter.

[00230] Clause 17. The machine readable storage media of any of clauses 12 through

14, wherein the first LBT is a category 4 (Cat 4) LBT, the operation comprising: perform a short LBT, in response to the completion of the Cat 4 LBT procedure subsequent to the start time and prior to the end time; and initiate transmission of at least one UL sub-frame, in response to the completion of the short LBT prior to the end time.

[00231] Clause 18. The machine readable storage media of any of clauses 12 through

14, wherein the UL grant is a first UL grant, the start time is a first start time, the end time is a first end time, the operation comprising: process a second UL grant to transmit UL sub- frames between a second start time and a second end time on the channel in the unlicensed spectrum; in response to the second UL grant, initiate a second LBT procedure; and in response to the second LBT procedure not completing prior to the end time, continue the second LBT procedure beyond the second end time such that the second LBT procedure is completed after the second end time.

[00232] Clause 19. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising: a memory; and one or more processors to: select a first value for a contention window; perform a category 4 (Cat 4) Listen-Before-Talk (LBT) procedure based at least in part on the first value for the contention window; initiate transmission, to an Evolved Node B (eNB), of a plurality of Uplink (UL) sub-frames based at least in part on a completion of the Cat 4 LBT within a scheduled duration, wherein one or more of the plurality of UL sub-frames are classified as reference sub-frames; process a request from the eNB to re-transmit the reference sub-frames in accordance with a Hybrid Automatic Repeat Request (HARQ) process; initiate retransmission, to the eNB, of at least the reference sub-frames; and select a second value for the contention window, in response to processing the request from the eNB to re-transmit the reference sub-frames.

[00233] Clause 20. The apparatus of clause 19, wherein the reference sub-frames are starting sub-frames of a most recent successful transmissions on a channel made by the UE that are initiated by UE by performing the Cat 4 LBT.

[00234] Clause 21. The apparatus of any of clauses 19 through 20, wherein the second value for the contention window is a next higher allowed value for the contention window after the first value of a priority class corresponding to the UL transmission.

[00235] Clause 22. The apparatus of any of clauses 19 through 21, wherein the one or more processors are to: subsequent to selecting the second value for the contention window, perform UL re-transmissions of the reference sub-frames in accordance with the HARQ process for at least a threshold number of times; and select a third value for the contention window, in response to performing the UL re-transmissions of the reference sub-frames in accordance with the HARQ process for at least the threshold number of times, wherein the second value for the contention window is a maximum allowed value for the contention window size of the priority class corresponding to the UL transmission.

[00236] Clause 23. The apparatus of clause 22, wherein the third value for the contention window is a minimum allowed value for the contention window for the priority class for which the reference sub-frames have been re-transmitted for at least the threshold number of times.

[00237] Clause 24. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of clauses 19 through 23.

[00238] Clause 25. The apparatus of any of clauses 19 through 23, comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00239] Clause 26. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising: select a first value for a contention window; perform a category 4 (Cat 4) Listen-Before-Talk (LBT) procedure based at least in part on the first value of the contention window; initiate transmission, to an Evolved Node B (eNB), of a plurality of Uplink (UL) sub-frames based at least in part on a completion of the Cat 4 LBT within a scheduled duration, wherein one or more of the plurality of UL sub-frames are classified as reference sub-frames; process a request from the eNB to re-transmit the reference sub-frames in accordance with a Hybrid Automatic Repeat Request (HARQ) process; initiate re-transmisison, to the eNB, of at least the reference sub-frames; and select a second value for the contention window, in response to processing the request from the eNB to re-transmit the reference sub-frames.

[00240] Clause 27. The machine readable storage media of clause 26, wherein the reference sub-frames are starting sub-frames of a most recent successful transmissions on a channel made by the UE that are initiated by UE by performing the Cat 4 LBT.

[00241] Clause 28. The machine readable storage media of clause 26, wherein the second value for the contention window is a next higher allowed value for the contention window after the first value of a priority class corresponding to the UL transmission.

[00242] Clause 29. The machine readable storage media of any of clauses 26 through

28, wherein the second value for the contention window is a maximum allowed value for the contention window size of the priority class, the operation comprising: subsequent to selecting second value for the contention window, initiate UL re-transmissions of the reference sub-frames in accordance with the HARQ process for at least a threshold number of times; and select a third value for the contention window, in response to initiating the UL retransmissions of the reference sub-frames in accordance with the HARQ process for at least the threshold number of times, wherein the third value for the contention window is a minimum allowed value for the contention window for the priority class for which the reference sub-frames have been re-transmitted for at least the threshold number of times.

[00243] Clause 26. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising: a memory; and one or more processors to: process an Uplink (UL) grant to transmit UL sub-frames on at least a first channel and a second channel in an unlicensed spectrum; conduct a category 4 (Cat 4) Listen- Before-Talk (LBT) procedure on the first channel; initiate transmission of one or more first UL sub-frames on the first channel, in response to a completion of the Cat 4 LBT procedure on the first channel; conduct a short LBT on the second channel, in response to the completion of the Cat 4 LBT procedure on the first channel; and initiate transmission of one or more second UL sub-frames on the second channel, in response to the completion of the short LBT on the second channel.

[00244] Clause 27. The apparatus of clause 26, wherein the one or more processors are to: conduct the Cat 4 LBT procedure on the first channel, upon randomly selecting the first channel from among the first channel and the second channel.

[00245] Clause 28. The apparatus of any of clauses 26 or 27, wherein the one or more processors are to: maintain and dynamically update a common contention window value for both the first channel and the second channel; and conduct the Cat 4 LBT procedure on the first channel based upon the common contention window value.

[00246] Clause 29. The apparatus of any of clauses 26 or 27, wherein the one or more processors are to: maintain and dynamically update (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel; and select a largest contention window value from among the first contention window value and the second contention window value for a priority class corresponding to the UL transmission; and conduct the Cat 4 LBT procedure on the first channel based upon the largest contention window value.

[00247] Clause 30. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of clauses 26 through 29.

[00248] Clause 31. The apparatus of any of clauses 26 through 29, comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00249] Clause 32. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising: process an Uplink (UL) grant to transmit UL sub-frames on at least a first channel and a second channel in an unlicensed spectrum; conduct a category 4 (Cat 4) Listen-Before-Talk (LBT) procedure on the first channel; initiate transmission of one or more first UL sub-frames on the first channel, in response to a completion of the Cat 4 LBT procedure on the first channel; conduct a short LBT on the second channel, in response to the completion of the Cat 4 LBT procedure on the first channel; and initiate transmission of one or more second UL sub-frames on the second channel, in response to the completion of the short LBT on the second channel.

[00250] Clause 33. The machine readable storage media of clause 32, the operation comprising: randomly select the first channel from among the first channel and the second channel, to conduct the Cat 4 LBT procedure on the first channel.

[00251] Clause 34. The machine readable storage media of any of clauses 32 or 33, the operation comprising: maintain and dynamically update a common contention window value for both the first channel and the second channel; and use the common contention window value to conduct the Cat 4 LBT procedure on the first channel.

[00252] Clause 35. The machine readable storage media of any of clauses 32 or 33, the operation comprising: maintain and dynamically update (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel; and select a largest contention window value from among the first contention window value and the second contention window value for a priority class corresponding to the UL transmission; and conduct the Cat 4 LBT procedure on the first channel based upon the largest contention window value.

[00253] Clause 36. An apparatus of a User Equipment (UE) operable to communicate with an Evolved Node B (eNB) on a wireless network, comprising: a memory; and one or more processors to: process an Uplink (UL) grant to transmit UL sub-frames on at least a first channel and a second channel in an unlicensed spectrum; conduct a first category 4 (Cat 4) Listen-Before-Talk (LBT) procedure on the first channel and a second Cat 4 LBT procedure on the second channel; initiate transmission of one or more first UL sub-frames on the first channel, in response to a completion of the first Cat 4 LBT procedure on the first channel; and initiate transmission of one or more second UL sub-frames on the second channel, in response to a completion of the second Cat 4 LBT procedure on the second channel.

[00254] Clause 37. The apparatus of clause 36, wherein the one or more processors are to: maintain and dynamically update (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel; conduct the first Cat 4 LBT procedure on the first channel based upon the first contention window value; and conduct the second Cat 4 LBT procedure on the second channel based upon the second contention window value.

[00255] Clause 38. The apparatus of clause 36, wherein the one or more processors are to: maintain and dynamically update (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel; select a largest contention window value from among the first contention window value and the second contention window value for a priority class corresponding to the UL transmission; and conduct the first Cat 4 LBT procedure on the first channel and the second Cat 4 LBT procedure on the second channel, based upon the largest contention window value.

[00256] Clause 39. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of clauses 36 through 38.

[00257] Clause 40. The apparatus of any of clauses 36 through 38, comprising a transceiver circuitry for generating transmissions and processing transmissions.

[00258] Clause 41. Machine readable storage media having machine executable instructions that, when executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising: process an Uplink (UL) grant to transmit UL sub-frames on at least a first channel and a second channel in an unlicensed spectrum; conduct a first category 4 (Cat 4) Listen-Before-Talk (LBT) procedure on the first channel and a second Cat 4 LBT procedure on the second channel; initiate transmission of one or more first UL sub- frames on the first channel, in response to a completion of the first Cat 4 LBT procedure on the first channel; and initiate transmission of one or more second UL sub-frames on the second channel, in response to a completion of the second Cat 4 LBT procedure on the second channel.

[00259] Clause 42. The machine readable storage media of clause 41, the operation comprising: maintain and dynamically update (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel; use the first contention window value to conduct the first Cat 4 LBT procedure on the first channel; and use the second contention window value to conduct the second Cat 4 LBT procedure on the second channel.

[00260] Clause 43. The machine readable storage media of clause 41, the operation comprising: maintain and dynamically update (i) a first contention window value for the first channel and (ii) a second contention window value for the second channel; select a largest contention window value from among the first contention window value and the second contention window value for the priority class corresponding to the UL transmission; and use the largest contention window value to conduct the first Cat 4 LBT procedure on the first channel and the second Cat 4 LBT procedure on the second channel.

[00261] Clause 44. The apparatus of any of clauses 1 through 9, 19 through23, 26 through 29, and 36 through 38, wherein the one or more processors comprise a baseband processor.

[00262] Clause 45. The apparatus of any of clauses 1 through 9, 19 through23, 26 through 29, and 36 through 38, comprising a memory for storing instructions, the memory being coupled to the one or more processors.

[00263] An abstract is provided that will allow the reader to ascertain the nature and gist of the technical disclosure. The abstract is submitted with the understanding that it will not be used to limit the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMS We claim:

1. An apparatus of a User Equipment (UE) operable to communicate with an Evolved

Node-B (eNB) on a wireless network, comprising:

a memory for storing instructions; and

one or more processors to:

process an Uplink (UL) grant to transmit UL sub-frames between a start time and an end time on a channel in an unlicensed spectrum;

conduct a Listen-Before-Talk (LBT) procedure subsequent to processing the UL grant; and

initiate transmission of one or more UL sub-frames, in response to a completion of the LBT procedure prior to the end time.

2. The apparatus of claim 1 , wherein the LBT is a category 4 (Cat 4) LBT, and wherein the one or more processors are to:

perform a short LBT prior to the start time, in response to the completion of the Cat 4 LBT procedure substantially prior to the start time; and initiate transmission of the one or more UL sub-frames from the start time to the end time, in response to the completion of the Cat 4 LBT and a completion of the short LBT prior to the start time.

3. The apparatus of claim 1 , wherein the LBT is a category 4 (Cat 4) LBT, and wherein the one or more processors are to:

perform a short LBT, in response to the completion of the Cat 4 LBT procedure subsequent to the start time and prior to the end time; and

initiate transmission of at least one UL sub-frame, in response to the completion of the short LBT prior to the end time.

4. The apparatus of claim 1 , wherein the LBT is a category 4 (Cat 4) LBT, and wherein the one or more processors are to:

initiate transmission of the one or more UL sub-frames from the start time to the end time, in response to the completion of the Cat 4 LBT procedure within a threshold duration from the start time, and without performing a short LBT prior to the transmission of the one or more UL sub-frames.

5. The apparatus of any of claims 1 through 3, wherein the LBT is a first LBT, the UL grant is a first UL grant, the start time is a first start time, and the end time is a first end time, and wherein the one or more processors are to:

process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum;

initiate a second LBT procedure, in response to the second UL grant; and

halt the second LBT procedure at the second end time, in response to the second LBT procedure not completing prior to the second end time.

6. The apparatus of claim 5, wherein the one or more processors are to:

perform the second LBT procedure by decrementing a first counter, wherein the first counter has a first value when the second LBT procedure is halted at the second end time; and

store the first value of the first counter, in response to the second LBT procedure not completing prior to the second end time.

7. The apparatus of claim 6, wherein the one or more processors are to:

process a third UL grant to transmit UL sub-frames between a third start time and a third end time on the channel in the unlicensed spectrum; and

initiate a third LBT procedure in response to the third UL grant,

wherein a second counter associated with the third LBT procedure is initialized to the first value of the first counter.

8. The apparatus of any of claims 1 through 3, wherein the LBT is a first LBT, the UL grant is a first UL grant, the start time is a first start time, and the end time is a first end time, and wherein the one or more processors are to:

process a second UL grant to transmit UL sub-frames between a second start time and a second end time on the channel in the unlicensed spectrum, wherein the second UL grant is associated with a UL burst on the channel by multiple UEs, and wherein the UL burst is scheduled to end at a UL burst end time;

initiate a second LBT procedure, in response to the second UL grant; and halt the second LBT procedure at the UL burst end time, in response to the second LBT procedure not completing prior to the UL burst end time.

9. The apparatus of any of claims 1 through 3, wherein the LBT is a first LBT, the UL grant is a first UL grant, the start time is a first start time, and the end time is a first end time, and wherein the one or more processors are to:

initiate a second LBT procedure, in response to the second UL grant; and

continue the second LBT procedure beyond the second end time such that the second LBT procedure is completed after the second end time, in response to the second LBT procedure not completing prior to the first end time.

10. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of claims 1 through 9.

1 1. The apparatus of any of claims 1 through 10, comprising a transceiver circuitry for

generating transmissions and processing transmissions.

12. Machine readable storage media having machine executable instructions that, when

executed, cause one or more processors of a User Equipment (UE) to perform an operation comprising:

conduct a category 4 (Cat 4) Listen-Before-Talk (LBT) procedure, in response to the

UL grant; and

initiate transmission of one or more UL sub-frames, in response to a completion of the Cat 4 LBT procedure prior to the end time.

13. The machine readable storage media of claim 12, the operation comprising: perform a short LBT prior to transmitting the one or more UL sub-frames from the start time to the end time, in response to the completion of the Cat 4 LBT procedure substantially prior to the start time.

14. The machine readable storage media of claim 12, the operation comprising:

initiate transmission of the one or more UL sub-frames from the start time to the end time, without performing a short LBT prior to the transmission of the one or more UL sub-frames, in response to a completion of the Cat 4 LBT procedure within a threshold duration from the start time.

15. The machine readable storage media of any of claims 12 through 14, wherein the UL grant is a first UL grant, the start time is a first start time, the end time is a first end time, the operation comprising:

in response to the second UL grant, initiate a second LBT procedure; and

in response to the second LBT procedure not completing prior to the end time, halt the second LBT procedure at the second end time.

16. The machine readable storage media of claim 15, the operation comprising:

perform the second LBT procedure by decrementing a first counter, wherein the first counter has a first value when the second LBT procedure is halted at the second end time;

in response to the third UL grant, initiate a third LBT procedure,

17. The machine readable storage media of any of claims 12 through 14, wherein the first LBT is a category 4 (Cat 4) LBT, the operation comprising:

perform a short LBT, in response to the completion of the Cat 4 LBT procedure

subsequent to the start time and prior to the end time; and initiate transmission of at least one UL sub-frame, in response to the completion of the short LBT prior to the end time.

18. The machine readable storage media of any of claims 12 through 14, wherein the UL grant is a first UL grant, the start time is a first start time, the end time is a first end time, the operation comprising:

in response to the second UL grant, initiate a second LBT procedure; and

in response to the second LBT procedure not completing prior to the end time,

continue the second LBT procedure beyond the second end time such that the second LBT procedure is completed after the second end time.

19. An apparatus of a User Equipment (UE) operable to communicate with an Evolved

Node-B (eNB) on a wireless network, comprising:

a memory; and

one or more processors to:

select a first value for a contention window;

perform a category 4 (Cat 4) Listen-Before-Talk (LBT) procedure based at least in part on the first value for the contention window;

initiate transmission, to an Evolved Node-B (eNB), of a plurality of Uplink (UL) sub- frames based at least in part on a completion of the Cat 4 LBT within a scheduled duration, wherein one or more of the plurality of UL sub-frames are classified as reference sub-frames;

process a request from the eNB to re-transmit the reference sub-frames in accordance with a Hybrid Automatic Repeat Request (HARQ) process;

initiate re-transmission, to the eNB, of at least the reference sub-frames; and select a second value for the contention window, in response to processing the request from the eNB to re-transmit the reference sub-frames.

20. The apparatus of claim 19,

wherein the reference sub-frames are starting sub-frames of a most recent successful transmissions on a channel made by the UE that are initiated by UE by performing the Cat 4 LBT.

21. The apparatus of any of claims 19 through 20,

wherein the second value for the contention window is a next higher allowed value for the contention window after the first value of a priority class corresponding to the UL transmission.

22. The apparatus of any of claims 19 through 21, wherein the one or more processors are to: subsequent to selecting the second value for the contention window, perform UL retransmissions of the reference sub-frames in accordance with the HARQ process for at least a threshold number of times; and

select a third value for the contention window, in response to performing the UL retransmissions of the reference sub-frames in accordance with the HARQ process for at least the threshold number of times,

wherein the second value for the contention window is a maximum allowed value for the contention window size of the priority class corresponding to the UL transmission.

23. The apparatus of claim 22,

wherein the third value for the contention window is a minimum allowed value for the contention window for the priority class for which the reference sub-frames have been re-transmitted for at least the threshold number of times.

24. A User Equipment (UE) device comprising an application processor, a memory, one or more antennas, a wireless interface for allowing the application processor to communicate with another device, and a touch-screen display, the UE device including the apparatus of any of claims 19 through 23.

25. The apparatus of any of claims 19 through 23, comprising a transceiver circuitry for generating transmissions and processing transmissions.