WO2018031136A1

WO2018031136A1 - Methods and devices to resolve transmit power disparity

Info

Publication number: WO2018031136A1
Application number: PCT/US2017/039743
Authority: WO
Inventors: Abhijeet Bhorkar; Huaning Niu; Jeongho Jeon; Qiaoyang Ye; Wenting CHANG
Original assignee: Intel IP Corporation
Priority date: 2016-08-12
Filing date: 2017-06-28
Publication date: 2018-02-15

Abstract

Devices, methods, user equipment (UE), evolved node B (eNB), and storage media are described suitable for eNBs operating in proximity with different transmit powers in order to resolve conflicts between the eNBs. Various embodiments are implemented in Long Term Evolution (LTE) systems operating in unlicensed channels. In one embodiment, a method to resolve transmit power disparity includes processing channel access information from a second eNB at a first eNB, determining a channel usage by the second eNB based on the channel access information, and managing use of the channel during the channel usage by the second eNB based on the channel access information, such that the processing and management at the first eNB is based on the transmit power disparity between the first eNB and the second eNB.

Description

METHODS AND DEVICES TO RESOLVE TRANSMIT POWER

DISPARITY

PRIORITY CLAIM

[0001] This application claims the benefit of priority to United States

Provisional Patent Application Serial No. 62/374,641, filed August 12, 2016, United States Provisional Patent Application Serial No. 62/415,209, filed October 31, 2016, and to United States Provisional Patent Application Serial No. 62/421,819 filed November 14, 2016, which are each incorporated herein by reference in entirety.

TECHNICAL FIELD

[0002] Embodiments pertain to systems, methods, and component devices for wireless communications, and particularly to the integration of long- term evolution (LTE), LTE- Advanced, and other similar wireless

communication systems with unlicensed frequencies. BACKGROUND

[0003] LTE and LTE-Advanced are standards for wireless

communication of high-speed data for user equipment (UE) such as mobile telephones. In LTE-Advanced and various wireless systems, carrier aggregation is a technology where multiple carrier signals operating on different frequencies may be used to carry communications for a single UE, thus increasing the bandwidth available to a single device. To improve performance, some LTE systems use channels mat are not exclusively reserved for the LTE system. Such channels are referred to as "unlicensed" channels or channels operating in unlicensed frequencies. One technology for enabling LTE system operation in unlicensed frequencies is known as "MuLTEfire". Another such system is known as LTE with license assisted access (LAA). BRIEF DESCRIPTION OF THE FIGURES

[0004] In the figures, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The figures illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document

[0005] FIG. 1 is a functional diagram of a wireless network, in accordance with some embodiments.

[0006] FIG. 2 illustrates components of a wireless communication network, in accordance with some embodiments.

[0007] FIG. 3 illustrates aspects of coexistence operations for multi- carrier operation on multiple unlicensed channels, in accordance with some embodiments.

[0008] FIG. 4 illustrates aspects of coexistence operations for multi- carrier operation on multiple unlicensed channels, in accordance with some embodiments.

[0009] FIG. 5 illustrates one example method for UE operation, in accordance with embodiments described herein.

[0010] FIG. 6 illustrates another example method for UE operation, in accordance with embodiments described herein.

[0011] FIG. 7 is a block diagram illustrating an example computer system machine which may be used in association with various embodiments described herein.

[0012] FIG. 8 illustrates aspects of a UE, a wireless apparatus, or a device, in accordance with some example embodiments.

DETAILED DESCRIPTION

[0013] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0014] FIG. 1 shows an example of a portion of an end-to-end network architecture of a network (e.g., an LTE network) with various components of the network, in accordance with some embodiments. Such a network architecture may be used to implement various communication system implementations, including systems that operate using frequencies dedicated exclusively to the system (e.g. "licensed" frequencies) as well as frequencies shared with other systems (e.g. "unlicensed" frequencies). "MuLTEfire", license-assisted access (LAA), and enhanced license-assisted access (ELAA) are LTE-based systems mat operate with wireless communication over unlicensed communication frequencies that can be implemented using the system of FIG. 1. The system of FIG. 1 includes various eNBs, which includes eNBs that operate using different transmission power for a given channel (e.g., low power eNBs and high power or macro eNBs).

[0015] Various embodiments described herein may be used in an LTE network which supports operations on unlicensed frequencies, such as the networks of FIGs. 1-2, or in any other such communication network. As used herein, "LTE network" refers to both LTE and LTE Advanced (LTE-A) networks, as well as other versions of LTE networks in development, such as 4G and SG LTE networks. The network may comprise a radio access network (RAN) (e.g., as depicted, the Evolved Universal Terrestrial Radio Access Network (E-UTRAN)) 100 and a core network 120 (e.g., shown as an evolved packet core (EPC)) coupled together through an SI interface 1 IS, as shown in FIG. 1. For convenience and brevity, only a portion of the core network 120, as well as the RAN 100, is shown in the example.

[0016] In other embodiments, multiple different LTE communication systems may operate in physical proximity to each other, such that a low power eNB from one system may be sufficiently close to a high power eNB from another system that the signals from the two eNBs may interfere with each other. Some systems for transmit power disparity described herein may thus involve more than one communication system similar to the system described in FIG. 1, or any other similar LTE-based communication systems. [0017] The core network 120 may include a mobility management entity

(MME) 122, a serving gateway (S-GW) 124, and a packet data network gateway (PDN GW) 126. The RAN 100 may include evolved nodeBs (eNBs) 104 (which may operate as base stations) for communicating with user equipments (UEs) 102. The eNBs 104 may include macro eNBs 104a and low-power (LP) eNBs 104b. The eNBs 104 may employ the techniques described herein.

[0018] The MME 122 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MME 122 may manage mobility aspects in access such as gateway selection and tracking area list management As part of such operations, the MME 122 assists with providing context information describing a particular UE 102 from S-GW 124 to an eNB 104 to enable the particular UE 102 to connect to the eNB 104. Such context information may be used by the eNBs 104 to assist with determining functionality and various operations in establishing a connection (e.g., Radio Resource Control (RRC) connections) between the eNB 104 and a particular UE 102.

[0019] The S-GW 124 may terminate the interface toward the RAN 100, and route data packets between the RAN 100 and the core network 120. In addition, the S-GW 124 may be a local mobility anchor point for inter-eNB handovers and also may provide an anchor for inter-3GPP mobility . Other responsibilities may include lawful intercept, charging, and some policy enforcement. As part of this functionality, at least a portion of the context information described above may be stored at the S-GW 124, and communicated or adjusted in communication with the MME 122. In various embodiments, the S-GW 124 and the MME 122 may be implemented in one physical node or separate physical nodes.

[0020] The PDN GW 126 may terminate an SGi interface (e.g., a 3GPP

LTE SGi interface) toward an external packet data network (PDN). The PDN GW 126 may route data packets between the core network 120 and the external PDN, and may perform policy enforcement and charging data collection. The PDN GW 126 may also provide an anchor point for mobility devices with non- LTE access. The external PDN can be any kind of internet protocol (IP) network, as well as an IP Multimedia Subsystem (IMS) domain. The PDN GW 126 and the S-GW 124 may be implemented in a single physical node or separate physical nodes.

[0021] The eNBs 104 (macro and LP) may terminate the air interface protocol and may be the first point of contact for a UE 102. In some

embodiments, an eNB 104 may fulfill various logical functions for the RAN 100 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management In accordance with some embodiments, the UEs 102 may be configured to communicate orthogonal frequency division multiplexed (OFDM)

communication signals with an eNB 104 over a multi-carrier communication channel in accordance with an orthogonal frequency-division multiple access (OFDMA) communication technique. The OFDM signals may comprise a plurality of orthogonal subcarriers.

[0022] The SI interface 115 may be the interface that separates the RAN

100 and the core network 120. It may be split into two parts: the Sl-U, which may carry traffic data between the eNBs 104 and the S-GW 124, and the Sl- MME, which may be a signaling interface between the eNBs 104 and the MME 122. An X2 interface may be the interface between pairs of the eNBs 104. The X2 interface may comprise two parts, the X2-C and X2-U. The X2-C may be the control -plane interface between the eNBs 104, while the X2-U may be the user- plane interface between the eNBs 104.

[0023] In cellular networks, the LP eNBs 104b in some embodiments are used to extend coverage to indoor areas where outdoor signals do not reach well, or to add network capacity in areas with dense usage. In particular, it may be desirable to enhance the coverage of a wireless communication system using cells of different sizes, such as macrocells, microcells, picocells, and femtocells, to boost system performance. The cells of different sizes may operate on the same frequency band, or may operate on different frequency bands with each cell operating on a different frequency band or only cells of different sizes operating on different frequency bands. As used herein, the term "LP eNB" refers to any suitable relatively LP eNB for implementing a smaller cell (smaller than a macrocell) such as a femtocell, a picocell, or a microcell. Femtocell eNBs are, in some embodiments, provided by a mobile network operator to its residential or enterprise customers. A femtocell, in some embodiments, is the size of a residential gateway or smaller and may generally connect to a broadband line. The femtocell may connect to the mobile operator's mobile network and provide extra coverage in a range of 30 to SO meters. Thus, an LP eNB 104b might be a femtocell eNB since it is coupled through the PDN GW 126. Similarly, a picocell may be a wireless communication system covering a small area, such as in-building (offices, shopping malls, train stations, etc.), or more recently, in-aircraft A picocell eNB may generally connect through the X2 link to another eNB such as a macro eNB through its base station controller

(BSC) functionality. Thus, an LP eNB 104b may be implemented with a picocell eNB since it may be coupled to a macro eNB 104a via an X2 interface. Picocell eNBs or other such devices may incorporate some or all functionality of a macro eNB 104a or LP eNB 104b. In some cases, this may be referred to as an access point base station or enterprise femtocell.

[0024] Communication over an LTE network may be split up into 10ms radio frames, each of which may contain ten 1ms subframes. Each subframe of the frame, in turn, may contain two slots of 0.5ms. Each subframe may be used for uplink (UL) communications from the UE 102 to the eNB 104 or downlink (DL) communications from the eNB 104 to the UE 102. In one embodiment, the eNB 104 may allocate a greater number of DL communications than UL communications in a particular frame. The eNB 104 may schedule transmissions over a variety of frequency bands. Each slot of the subframe may contain 6-7 OFDM symbols, depending on the system used. In one embodiment, each subframe may contain 12 subcarriers. In the 5G system, however, the frame size (in ms), the subframe size, and the number of subframes within a frame, as well as the frame structure, may be different from those of a 4G or LTE system. The subframe size, as well as the number of subframes in a frame, may also vary in the 5G system from frame to frame. For example, while the frame size may remain at 10ms in the SG system for downward compatibility, the subframe size may be decreased to 0.2ms or 0.25ms to increase the number of subframes in each frame. [0025] A downlink resource grid may be used for downlink

transmissions from an eNB to a UE, while an uplink resource grid may be used for uplink transmissions from a UE to an eNB or from a UE to another UE. The resource grid may be a time-frequency grid, which is the physical resource in the downlink in each slot The smallest time-frequency unit in a resource grid may be denoted as a resource element (RE). Each column and each row of the resource grid may correspond to one OFDM symbol and one OFDM subcarrier, respectively. The resource grid may contain resource blocks (RBs) mat describe the mapping of physical channels to resource elements and physical RBs (PRBs). A PRB may be the smallest unit of resources that can be allocated to a UE. An RB in some embodiments may be 180 kHz wide in frequency and one slot long in time. In frequency, RBs may be either 12 * 15 kHz subcarriers or 24 x 7.5 kHz subcarriers wide, dependent on the system bandwidth. In Frequency Division Duplexing (FDD) systems, both the uplink and downlink frames may be 10ms and frequency (full-duplex) or time (half-duplex) separated. The duration of the resource grid in the time domain corresponds to one subframe or two resource blocks. Each resource grid may comprise 12 (subcarriers) χ 14 (symbols) = 168 resource elements.

[0026] Each OFDM symbol may contain a cyclic prefix (CP), which may be used to effectively eliminate Inter Symbol Interference (1ST), and a Fast Fourier Transform (FFT) period The duration of the CP may be determined by the highest anticipated degree of delay spread. Although distortion from the preceding OFDM symbol may exist within the CP, with a CP of sufficient duration, preceding OFDM symbols do not enter the FFT period. Once the FFT period signal is received and digitized, the receiver may ignore the signal in the CP.

[0027] FIG. 2 illustrates a wireless network 200, in accordance with some embodiments. The wireless network 200 includes a UE 201 and an eNB 250 connected via one or more channels 280, 285 across an air interface 290. The UE 201 and eNB 250 communicate using a system that supports controls for managing the access of the UE 201 to a network via the eNB 250.

[0028] In the wireless network 200, the UE 201 and any other UE in the system may be, for example, laptop computers, smartphones, tablet computers, printers, rnachine-type devices such as smart meters or specialized devices for healthcare monitoring, remote security surveillance systems, intelligent transportation systems, or any other wireless devices with or without a user interface. The eNB 250 provides the UE 201 network connectivity to a broader network (not shown). This UE 201 connectivity is provided via the air interlace 290 in an eNB service area provided by the eNB 2S0. In some embodiments, such a broader network may be a wide area network operated by a cellular network provider, or may be the Internet Each eNB service area associated with the eNB 250 is supported by antennas integrated with the eNB 250. The service areas are divided into a number of sectors associated with certain antennas. Such sectors may be physically associated with fixed antennas or may be assigned to a physical area with tunable antennas or antenna settings adjustable in a beamforrrring process used to direct a signal to a particular sector. One embodiment of the eNB 250, for example, includes three sectors, each covering an approximately 120-degree area, with an array of antennas directed to each sector to provide 360-degree coverage around the eNB 250.

[0029] The UE 201 includes control circuitry 205 coupled with transmit circuitry 210 and receive circuitry 215. The transmit circuitry 210 and receive circuitry 215 may each be coupled with one or more antennas. The control circuitry 205 may be adapted to perform operations associated with wireless communications using congestion control. The control circuitry 205 may include various combinations of application-specific circuitry and baseband circuitry. The transmit circuitry 210 and receive circuitry 215 may be adapted to transmit and receive data, respectively, and may include radio frequency (RF) circuitry or front end module (FEM) circuitry. In various embodiments, aspects of the transmit circuitry 210, receive circuitry 215, and control circuitry 205 may be integrated in various ways to implement the circuitry described herein. The control circuitry 205 may be adapted or configured to perform various operations such as those described elsewhere in mis disclosure related to a UE. The transmit circuitry 210 may transmit a plurality of multiplexed uplink physical channels. The plurality of uplink physical channels may be multiplexed according to time division multiplexing (TDM) or frequency division multiplexing (FDM) along with carrier aggregation. The transmit circuitry 210 may be configured to receive block data from the control circuitry 205 for transmission across the air interface 290. Similarly, the receive circuitry 215 may receive a plurality of multiplexed downlink physical channels from the air interface 290 and relay the physical channels to the control circuitry 205. The plurality of downlink physical channels may be multiplexed according to TDM or FDM along with carrier aggregation. The transmit circuitry 210 and the receive circuitry 215 may transmit and receive both control data and content data (e.g., messages, images, video, etc.) structured within data blocks that are carried by the physical channels. For a device configured for low-bandwidth or irregular communications (e.g., utility meters, stationary sensors, etc.), customized circuitry and antennas may be used to enable communications on a narrow bandwidth (e.g., 180 kHz, or other similar narrow bandwidths) to enable the device to consume small amounts of network resources.

[0030] FIG. 2 also illustrates the eNB 250, in accordance with various embodiments. The eNB 250 circuitry may include control circuitry 255 coupled with transmit circuitry 260 and receive circuitry 265. The transmit circuitry 260 and receive circuitry 265 may each be coupled with one or more antennas that may be used to enable communications via the air interface 290.

[0031 ] The control circuitry 255 may be adapted to perform operations for managing channels and congestion control communications used with various UEs, including communication of open mobile alliance (OMA) management objects (OMA-MOs) describing application categories, as detailed further below. The transmit circuitry 260 and receive circuitry 265 may be adapted to transmit and receive data, respectively, to any UE connected to the eNB 250. The transmit circuitry 260 may transmit downlink physical channels comprised of a plurality of downlink subframes. The receive circuitry 265 may receive a plurality of uplink physical channels from various UEs including the UE 201. In embodiments described herein, the receive circuitry 265 may receive a plurality of uplink physical channels simultaneously on multiple unlicensed- frequency channels from a single UE.

[0032] For wireless network imp] ementations such as those illustrated by

FIGs. 1 and 2, there is an increasing demand for high data rates over wireless, but the usable licensed spectrum is of limited physical extent This is the rationale behind the emerging interest in the operation of LTE systems in the unlicensed spectrum in the 3rd Generation Partnership Project (3GPP), as described above.

[0033] Apart from the License Assisted Long-Term Evolution (LTE) operation for unlicensed spectrum, LTE may also be operated via dual connectivity or a standalone LTE mode, which use limited or no assistance from the licensed spectrum. "MuLTEfire" systems use no assistance from the licensed spectrum to enable a leaner, self-contained network architecture that is suitable for neutral deployments in the unlicensed spectrum. Some embodiments of standalone unlicensed LTE systems such as MuLTEfire use 3.5GHz as an unlicensed frequency band. Third generation partnership project (3GPP) systems may also consider the operation of new radio (NR.) or License Assisted Access (e)(LAA) systems on 3.S GHz Citizens Broadband Radio Service (CBRS) spectrum. The 3.S GHz band was previously blocked from use by public communication systems by the U. S. Department of Defense (DoD). In the

United States, the US Federal Communication Commission (FCC) has adopted a three-tiered access model for 3.5 GHz CBRS band as follows: 1. Incumbent (Federal user, Fixed Satellite Service); 2. Priority access licensees (PALs): 100 MHz, auction for short-term licensing; 3. General authorized access (GAA): ISO MHz open for any one with an FCC-certified device.

[0034] According to the above order of priority, the channel accessed by higher priority (e.g., group 1-inclumbent users) is protected from lower priorities (e.g., group 3 GAA). For instance, the channel accessed by PAL is protected from GAA whereas PAL should not hinder the channel accessed by incumbent use. Note, however, that no particular coexistence rule, such as listen before talk (LBT), is mandated by the FCC among GAAs. The FCC has defined the spectrum access system (SAS) that authorizes and manages the use of the CBRS (PAL, GAA) spectrum. It is up to SAS to maintain the prioritized channel access. As a frequency coordinator, SAS optimizes frequency use to facilitate coexistence. It is possible that SAS may have limited coexistence provisioning between GAAs by means of spectrum coordinatioa

[0035] The FCC requires that transmission equipment with specific and standardized capabilities are employed by CBRS operators for use in the 3.S GHz band. This equipment is called Citizens Broadband Service Device ("CBSD"). CBDSs are fixed stations or networks of stations. There are two types of CBDSs: Category A (e.g. , a lower power CBSD for indoor use which may be used with LP eNBs as described above) and Category B (e.g., a higher power CBSD for outdoor use which may include high power or macro eNBs as described above). The FCC has defined power limits for CBSD, as shown in Table 1. Table 1 shows that there can be a large disparity between category A and category B, i.e., indoor evolved eNBs may have equivalent isotropically radiated power (E1RP) up to 30 dBm, while outdoor eNBs may have EIRP up to 47 dBm.

Table 1: Power limits for CBSD (PAL, GAA)

[0036] In various embodiments described herein, MuLTEfire (MF) communication systems can operate either as PAL or GAA If MF operates as GAA in 3.5 GHz band, the associated MF design may be updated to provide fairness and optimized quality of service (QoS) guarantee.

[0037] For issues with the power disparity between category A and category B CBSD, embodiments described herein may include one or more of the following: i) Energy detect (ED) threshold adaptation based on transmission power, ii) Preamble transmission before the burst to indicate total burst duration; and/or iii) Using conventional physical downlink control channel (CPDCCH) to indicate current/next subframe indication that can be detected by nearby transmitters to defer transmissioa While it may be possible if MF/eLAA for 5 GHz can work as it does in the 3.5GHzCBRS band to avoid additional design overhead, the Rel-13 LAA ED threshold rule may be redesigned, which may not differentiate Tx power over 23 dBm

[0038] FIG. 3 describes the coexistence issue of an outdoor high power eNB 350 and indoor low power eNB 360. Due to high transmission power, outdoor eNB 3S0 may silence/block other transmitters in a wide range including indoor eNBs such as low power eNB 360. On the other hand, the indoor low power eNB 360 may not be able to symmetrically silence the outdoor eNB 350 due to lower transmission power. As illustrated by FIG. 3, eNB 350 is communicating with UE 310 via wireless connection 352 and UE 312 via wireless connection 354. Although signal 369 is shown as reaching UE 312, this signal 369 from low power eNB 360 is not able to silence the signal of wireless connection 354 from high power eNB 350. ENB 360 is cornmumcating with UE 314 via wireless connection 362 and UE 316 via wireless connection 364. Due to the physical proximity of high power outdoor eNB 350 and low power indoor eNB 360 with transmit power disparity, coexistence problems arise. In the illustration of FIG. 3, interfering signal 359 from high power outdoor eNB 350 causes problems with wireless connection 364, and may overpower or silence the connection from eNB 360 to UE 316.

[0039 ] As detailed above, in various embodiments eNB 350 and eNB 360 may be part of the same communication system within a single RAN such as RAN 100. In other embodiments, however, eNB 350 and eNB 360 are in different communication systems that are bom accessing the same unlicensed frequencies (e.g., an unlicensed channel). Aspects of the various embodiments described herein allow eNBs in either situation to manage transmit power disparity to avoid asymmetric silencing of another eNB.

[0040 ] As described below, embodiments herein enable eNBs with transmit disparity issues to use channel access information from other eNBs to determine when to avoid using an unlicensed channel as part of system coexistence to prevent the asymmetric silencing issues described above, particularly for low power eNBs communicating with UEs that are within a boundary area between a lower power eNB and a higher power eNB.

[0041] FIG. 4 illustrates one example method 400 for eNB operation, in accordance with embodiments described herein. The method 400 may be implemented by an apparatus of an eNB, or by various circuitry of an eNB. In some embodiments, the method 400 is embodied by a computer-readable storage medium comprising instructions that, when executed by processing circuitry, cause an eNB to perform the operations of the method 400.

[0042 ] The embodiment of FIG. 4 begins with operation 405 where an apparatus of a first eNB processes unlicensed channel access information received from a second eNB. The unlicensed channel access information may take different forms in various different embodiments, which are described in more detail below.

[0043] Following processing of the unlicensed channel access information in operation 403, in operation 410, the first eNB determines an expected usage of the unlicensed channel (e.g., unlicensed channel usage) from the unlicensed channel access information received from the second eNB. In some embodiments, this includes a duration of the expected usage by the second eNB; in some embodiments this includes a specified number of uplink and/or downlink subfrarnes to be communicated by the second eNB to a UE having a link to the second eNB. In still further embodiments, the usage is simply current usage determined by an adjusted energy detection threshold (hat is adapted in view of the transmit power disparity between the first eNB and the second eNB.

[0044] Operation 41S then involves the first eNB managing the first eNB's use of the unlicensed channel during the unlicensed channel usage by the second eNB (e.g., as determined at the first eNB in operation 410) based on the unlicensed channel access information. In operation 415, the unlicensed channel usage by the first eNB is managed, at least in part, according to a transmit power disparity on the unlicensed channel between the first eNB and the second eNB. In various embodiments, the unlicensed channel access information may be processed differently based on the type of unlicensed channel access information and the particular coexistence management operations supported by the system. Further details of various implementations of unlicensed channel access information and management of unlicensed channel use are detailed below.

[0045] FIG. 5 illustrates one example method 500 for eNB operation, in accordance with embodiments described herein. The method 500 may be implemented by an apparatus of an eNB, or by various circuitry of an eNB. In some embodiments, the method 300 is embodied by a computer-readable storage medium comprising instructions that, when executed by processing circuitry, cause an eNB to perform the operations of the method 500. In some embodiments, method 500 is a method performed by an eNB that is located near another eNB such that the eNBs may have coexistence issues based on transmit power disparity on an unlicensed channel. Thus, in some embodiments, a first eNB may perform method 400 while a second eNB performs method 500.

[0046] Method 500 begins with, a second eNB processing data for a data transmission on an unlicensed channel in operation 505. As detailed above, use of such an unlicensed channel may be as part of an LTE-based communication system for use with shared frequencies such as MuLTEfire or other such systems. The data may be any payload or control data to be transmitted or received by the second eNB on an unlicensed frequency. This may include data to be transmitted to aUE from the second UE, as well as scheduling information for data to be received at the second eNB from the UE.

[0047] In operation 510, the second eNB determines unlicensed channel usage for the unlicensed channel associated with the data transmission from operation 505. Similar to the operations above in method 400, this usage data may be specific, including details of UL and DL subframes, or more generally detailing expected channel occupancy times or other such information.

[0048] Unlicensed channel access information is then generated by the second eNB in operation 515. This information is generated based on the unlicensed channel usage and a transmit power disparity between the second eNB and a first eNB within a threshold distance of the second eNB (e.g., system design details or information such as power thresholds for different eNB categories).

[0049] Transmission of the unlicensed channel access information is initiated in operation 520, and in operation 525, the second eNB (e.g., an apparatus of the second eNB) initiates transmission of the data transmission following transmission of the unlicensed channel access infonnation. In addition to the coexistence operations above, additional coexistence operations may also be performed by the second eNB. For example, in addition to initiating transmission of the unlicensed channel access information, a listen before talk (LBT) operation may also be performed prior to any transmission on the unlicensed channel for coexistence with non-LTE-based systems or any system not compatible with the unlicensed channel access information. Further details of various implementations of unlicensed channel access information and management of unlicensed channel use are detailed below.

[0050] In some embodiments, one or more of the following three operational systems may be used to address the transmit power disparity identified above in Table 1 (e.g., category A and category B transmit disparity): i) ED threshold adaptation based on transmission power; ii) Clear to Send (CTS) systems including a) preamble transmission before the burst to indicate total burst duration (N AV) or b) scrambling physical downlink control channel (PDCCH) without Radio Network Temporary Identifier (RNTl) and indicating current/next subframe duration indication that can be detected by nearby transmitters to defer transmission, including PDCCH transmitted by low power nodes (LPNs) to indicate a total burst duration or a set of subframes which are occupied for transmission, such that nearby devices receiving the PDCCH defer to the identified burst (e.g., data transmission); iii) Enhanced Inter-Cell

Interference Coordination (elCIC) style systems, where a PDCCH is transmitted by high power nodes (HPNs) (e.g., category B CBSDs) to indicate a muting pattern (e.g., which subframes will be muted such that nearby devices receiving the indication can use the muted subframes to transmit), such (hat nearby devices can defer transmission in the subframes where the HPN transmits (e.g., as identified by the muting pattern). In some systems various combinations of the above three may provide that a low power eNB is able to effectively block a high power node.

[0051 ] In some systems, the processing and management of unlicensed channel access information is based on an energy detection (ED) threshold adaptation in the system design based on transmission power values within a system. In other words, certain eNBs are designated as different eNB types with different transmission thresholds, and coexistence operations for the eNBs are based on the ED thresholds that are a part of the communication system operational design. [0052] In such embodiments, a resolution of ED threshold adaptation according to the transmission power is extended. In previous systems, such as in Rel-13 LAA, an ED threshold rule is present with an ED threshold fixed at -72 dBm for power transmissions above 23 dBm and -62 dBm for power transmissions below 13 dBm, with a linear variation in the ED threshold between these two points. The ED threshold for a discovery reference signal has a similar ED threshold shape, but with break points at 18dBm and 28dBm instead of the corresponding break points at 13 dBm and 23dBm for the physical downlink shared channel ED threshold described above.

[0053] In some embodiments described herein, an ED threshold is used to compensate for different transmission power values from different eNBs. In one embodiment, an ED threshold X is set as:

In other embodiments, ED threshold X is set as:

(2) X= max(-82,-72+ (23 + 10■ log 10(5 WMHzl 2QMHZ) -P_TX )dBm [0055] In still further eirnbodiments, the value of the ED threshold may be semi-statically set based on system operation, and indicated to an eNB based on testing of communications between proximate eNBs. In some embodiments, such an ED threshold is fixed for an entire operation of an eNB. The value of an ED threshold if indicated semi-statically to an eNB may be indicated by S AS signaling. Thus, in accordance with the methods above, in some embodiments, the unlicensed channel access information comprises transmissions by a first eNB where a second eNB senses the first eNB's transmission using an ED threshold adapted based on the transmission power disparity between the eNBs. In some embodiments, this is implemented as an ED threshold such as that of equations 1 or 2 above. In other embodiments, this includes a threshold mat is semi-statically or statically fixed based on eNB placement or system operational testing. [0056] In addition to Hie embodiments above where an ED threshold is adapted to manage power transmit disparity, some embodiments operate with a preamble transmission before the burst (e.g., data transmission) to indicate total burst duration. Such a preamble comprises unlicensed channel access information in accordance with various embodiments. In such embodiments, an eNB may transmit a preamble indicating duration of the burst including expected number of downlink (DL) and uplink (UL) subframes. In other embodiments, only an expected duration or other information may be included in the unlicensed channel access information (e.g., preamble).

[0057] For such systems, the preamble is effectively broadcasted before the transmission of the data transmission burst An eNB receiving the preamble may perform blind detection of the preamble as part of receiving and processing the unlicensed channel access information. Upon reception of the preamble, a nearby receiver that successfully received the preamble may refrain from any transmission during the burst duration indicated by the preamble as part of processing the unlicensed channel access information or managing use of the unlicensed channel based on this information. In some such embodiments, upon reception of the preamble, the nearby receiver that successfully received the preamble refrains from performing LBT during the burst duration indicated by the preamble. In other embodiments, detection of the preamble is used as information along with LBT processes to determine whether a receiving eNB will transmit on the unlicensed channel.

[0058] As part of some such embodiments, the information in the unlicensed channel access information (e.g., burst duration information) may be encoded via tail-biting convolutional code (TBCC) at 1/3 rate and quadrature phase shift keying (QPSK) modulatioa In some such embodiments, for demodulation of the burst information, cell-specific reference signal (CRS) or demodulation reference signal (DMRS) signal is modified so that preamble is detectable by all nearby eNBs. A CRS uses sequences whose generation is dependent on the cell ID. In order to reduce the blind decoding attempts at the eNB in some embodiments, a cell ID (CTD) used for cinit is set to a default value for CRS scrabbling. In one embodiment, the default cell ID used is 0. In other embodiment, the default cell ED used is set by SAS signaling. In some embodiments, CRS mapping for the preamble occurs according to the default cell ID, and preamble sequence presence detection is performed with CRS detection. Thus, in some embodiments, for scrambling:

and for multiplexing and scrambling:

in accordance with LTE specified cinit definitions.

[0059 ] Further, in some embodiments using a preamble for unlicensed channel access information, the performance/blind detection of a preamble can be improved with PSS/SSS sequences in the preamble. In some embodiments, a preamble may span over one or more orthogonal frequency-division multiplexing (OFDM) symbols. In various embodiments, a primary synchronization signal (PSS) is present in the first symbol of the preamble in the middle 6RBs. In one embodiment, a secondary synchronization signal (SSS) is present in the second symbol of the preamble in the middle 6RBs. In other embodiments, other structures with resource blocks used by a preamble configured with PSS or SSS signals to improve blind detection of the preamble are used.

[0060] The use of a common physical downlink control channel

(cPDCCH) in (e)LAA and also MF design by LPNs is also one possible implementation in accordance with embodiments described herein. In such embodiments, CPDCCH may be used to indicate the current/next subframe interval. While existing systems enable detection of CPDCCH only by UEs, in some embodiments described herein, the CPDCCH is also configured to be detected by receiving eNBs (e.g., eNBs configured to delay use of an unlicensed channel in response to unlicensed channel access information). In such embodiments, the CPDCCH is communicated from one eNB to another eNB operations as the unlicensed channel access information. In such embodiments, if Hie eNBs from the same operator receive the CPDCCH, the receiving eNB performs blind detection of CPDCCH over NID and performs different hypotheses over scrambling for CRS/CPDCCH. In other embodiments, the scrambling used for CPDCCH and CRS may use a default cell ID value of 0.

[0061 ] In some embodiments, upon detection of the CPDCCH (e.g., the unlicensed channel access information), the receiving eNB does not perform LBT for the duration of the current and next subframe interval indicated in the CPDCCH. In other embodiments, upon detection of CPDCCH, the receiving eNB does transmit for the duration of the current and next subframe interval indicated in the CPDCCH. In accordance with such embodiments, the CPDCCH can be enhanced to indicate the duration of the remaining burst (e.g., data transmission) duration.

[0062] In some embodiments, a set of sequences can be adopted for CRS, which is irrelevant to the cell ID. In some such embodiments, different sequences in this set are used to indicate different data transmission information (e.g., sequence 1 and sequence 2 denote the burst duration of 1 subframe and 2 subframes, respectively). Nearby devices perform hypothesis tests among the sets of sequences, and defer LBT and transmission operations for a duration corresponding to detected sequences. In one embodiment, the used sequences are newly designed or reused reserved phy sical random access channel

(PRACH) sequences, such that a category B high-power node can reuse the procedure of PRACH reception. In some embodiments, a gap exists between a preamble and a data burst, so as to leave processing time at a receiving node for detection.

[0063] As described above, PDCCH or CPDCCH communications may be used as unlicensed channel access information to indicate when a LPN schedules data transmissions. Specifically, the cPDDCH indicates the current/next subframe length, and the configuration (offset and duration) of a following UL burst LPNs can use the PDCCH to hold the unlicensed channel, with a PDCCH modified to include any of: a length of current/next subframe; a duration of a remaining transmission burst; and/or a set of subframes which will be used for transmission. In some embodiments, the set of subframes that are occupied can be restricted to subframes which schedule UEs at a cell edge (e.g., UE 316 or UE 312 in FIG. 3).

[0064] In some such embodiments, a new downlink control information

(DCS) format is defined for the PDCCH to cany the above information.

Alternatively, in some embodiments, existing DCI format 1 C or omer formats are reused to carry such information, with a new radio network temporary identifier (RNTI) different from a common cell RNTI (CC-RNTI) used to scramble the DCI.

[0065] For such PDCCH transmissions, the PDCCH can be transmitted in every DL subframe, or in a set of DL subframes (e.g., the beginning N DL subframes such as N=2 or N=3) or in every other subframe.

[0066] A third technique in some embodiments includes a CPDCCH being enhanced to indicate on which of the subframes the receiving eNB should not transmit. Such a system achieves a result similar to that of inter-cell interference coordination (ICIC), but using CPDCCH to manage coexistence for transmit power disparity. In such systems, high-power nodes broadcast a muting pattern, with nearby devices that receive the indication using muted subframes for LBT and transmission. In one embodiment, the muting pattern can be indicated as a bitmap or several muting patterns can be pre-defined or indicated via SAS, with the associated index indicated by HPNs. The muting granularity can be a radio frame, a subframe, or multiple consecutive subframes. Just as above for the PDCCH transmissions by LPNs, the HPN muting transmissions can be transmitted in every DL subframe, or in a set of DL subframes (e.g., the beginning N DL subframes such as N=2 or N=3) or in every other subframe.

[0067] PDCCH can be used to carry such muting patterns for HPNs (e.g., the set of subframes where the HPN will mute). Such PDCCH are common across cells. Nearby devices that receive the PDCCH can use the muted subframes for LBT and data transmissions. Such PDCCH systems may operate as described above.

[0068] In addition to PDCCH muting patterns (e.g., unlicensed channel access information), a set of sequences can be adopted to indicate a muting pattern. Such sequences can be common across cells. Different sequences in such a set are used to indicate different muting patterns. For example, sequence one and two can denote muting patterns one and two, respectively, where the muting pattern can be pre-defined, or indicated by SAS. Nearby devices (e.g., UEs or eNBs) perform hypothesis tests among the set of sequences, and perform LBT and transmissions for a duration corresponding to the muted subframes indicated by the detected sequence. For the sequence design, a reference signal (e.g., a cell-specific reference signal (CRS), demodulation reference signal (DMRS), or channel state information reference signal (CSI-RS)) can be used. CRS, DMRS, or CS1 signals can be modified so mat they are detectible by all nearby devices. The generation and remapping of these reference signals depends on the cell identifier (ID) in LTE systems. To make a preamble detectable by all nearby devices, the cell ID is set to a default value. These sequences may be newly designed sequences. In some embodiments, these sequences are reused reserved PRACH sequences.

[0069] Further embodiments may also use semi-statically configured muting patterns. In such embodiments, SAS can signal a muting pattern based on long-term estimation of interference scenarios. In one embodiment, SAS configures the muting pattern via a bitmap technique, where N bits can be used (e.g., N=10) and HPNs mute based on the N-bit indication, with the muting pattern repealing every N subframes. In other embodiments, a set of muting patterns can be predefined, with SAS indicating an index of a pattern to be used.

[0070] The different systems described above are not mutually exclusive.

Thus some embodiments may operate with ED threshold adaptation, preamble transmission, CPDCCH communications between both HFN and LPN eNBs, and various muting patterns Other systems may operate using any combination of any of the functions described above or managing transmission disparity coexistence between eNBs.

[0071 ] In addition to eNB performing the above detection operations,

UEs may also employ the above operations. For example, in some embodiments, a UE is configured to perform ED adjustment based on receipt of unlicensed channel access information transmission similar to eNB. In such a system, a UE with a wireless communication link to a first eNB established may detect unlicensed channel access information from a second eNB, and may adjust ED detection operations based on the unlicensed channel access information Similarly, in some embodiments, a UE performs preamble detection and employs a similar procedure as an eNB to refrain from transmitting for the burst interval indicated by transmitting eNB, or a UE performs CPDCCH detection and employs similar procedure as an eNB to refrain from transmitting for the burst interval indicated by the transmitting eNB. Thus, in various embodiments, any communication apparatus in some embodiments, whether an apparatus of a UE or an eNB, may be configured to: adapt energy detect (ED) threshold based on power transmission, transmit a preamble before a burst to indicate a burst duration, and indicate a subframe interval. Similarly, the apparatus processes for an apparatus of a UE or eNB described herein may include adapting an energy detect (ED) threshold based on power transmission, transmitting a preamble before a burst to indicate a burst duration that may include an expected number of downlink (DL) and uplink (UL) subframes, and indicating subframe interval. EXAMPLE EMBODIMENTS

[0072] In addition to the above example embodiments, any combination of operations or elements described above may be integrated into various embodiments described herein.

[0073] Example 1 is an apparatus, comprising: means for identifying a muting pattern indication associated with semi-static configuration by a spectrum access system (SAS); and means for performing LBT (listen before talk) and transmission on a muted subframe of an unlicensed spectrum in 3.5

Ghz band responsive to the muting pattern indication.

[0074] Example 2 may include the subject matter of example 1 and/or some other example herein, wherein the muting pattern indication is identified based on a bitmap.

[0075 ] Example 3 may include the subject matter of any of examples 1 -2 and/or some other example herein, wherein the bitmap corresponds to N bits and high power nodes are to mute based on N-bit indications.

[0076] Example 4 may include the subject matter of any of examples 1-3 and/or some other example herein, wherein the muting partem indication comprises an index to specify a subset of a set of predefined muting patterns. [0077] Example 5 may include the subject matter of any of examples 1 -3 and/or some other example herein, wherein the apparatus is a UE (user equipment) or a portion thereof, or an enhanced node B (eNB) or a portion thereof.

[0078 ] Example 6 is an apparatus, comprising: means for sexm-statically configuring a muting pattern for an unlicensed spectrum in 3.5 Ghz based on interference estimation; and means for causing a muting pattern indication to be broadcast based on the muting pattern.

[0079] Example 7 may include the subject matter of example 6 and/or some other example herein, wherein the muting pattern indication is bitmap based.

[0080] Example 8 may include the subject matter of any of examples 6-7 and/or some other example herein, wherein the broadcast is to repeat every N subframes and high-power nodes are to mute based on N-bit indications,

[0081] Example 9 may include the subject matter of any of examples 6-8 and/or some other example herein, wherein the muting pattern indication comprises an index.

[0082] Example 10 is may include elements of any other example herein, wherein the apparatus is a network device of an SAS (spectrum access system) or a portion thereof.

[0083] Example 11 may include the user equipment (UE) operating on an unlicensed spectrum capable of listen before talk (LBT), the UE configured to communicate with an enhanced node B (eNB) using a licensed medium and/or unlicensed medium

[0084] Example 12 may include the method of example 11 and/or some other example herein, wherein eNB performs LBT before scheduling a transmission burst

[0085] Example 13 may include the method of example 11 and/or some other example herein, wherein the eNB can be capable of performing transmission over a 3.5 GHz unlicensed spectrum.

[0086] Example 14 may include the method of example 13 and/or some other example herein, wherein an energy detect (ED) threshold of the eNB is modified beyond 23 dBm. [0087] Example IS may include the method of example 14 and/or some other example herein, wherein the ED threshold can be set as X = - 72+(23=101oglO(BWMHz/20MHz)-PTX)dBm.

[0088] Example 16 may include the method of example 14 and/or some other example herein, wherein the ED threshold can be set as

[0089] Example 17 may include the method of example 14 and/or some other example herein, wherein the value of the ED threshold is semi-statically indicated to the eNB, e.g., via spectrum access system (SAS) signaling, or is fixed for the entire operation of the eNB.

[0090] Example 18 may include the method of example 13 and/or some other example herein, wherein a clear to send (CTS)-to-Self approach can be used to reserve a channel.

[0091 ] Example 19 may include the method of example 18 and/or some other example herein, wherein a preamble is transmitted before the start of a burst

[0092] Example 20 may include the method of example 19 and/or some other example herein, wherein the preamble is effectively broadcasted before the transmission of the burst, and a receiver performs blind detection of the preamble. Upon reception of the preamble, the nearby receiver that successfully received the preamble refrains from performing LBT or any transmission during the burst duration indicated by the preamble.

[0093] Example 21 may include the method of example 19 and/or some other example herein, wherein the preamble can span one or multiple symbols.

[0094] Example 22 may include the method of example 19 and/or some other example herein, wherein the preamble can include one or multiple of the following: reference signal (e.g., CRS, DMRS or CSI-RS), synchronization signal (e.g., PSS or SSS), and data part including burst duration information.

[0095] Example 23 may include the method of example 22 and/or some other example herein, wherein the RSs can be modified to be detectable by any nearby devices.

[0096] Example 24 may include the method of example 23 and/or some other example herein, wherein the cell ID used in RS generation and/or its RE mapping can be set to a default value, e.g., 0, or can be signaled by SAS. For example, CRS uses gold sequences whose generation and RE mapping depends on the cell ID, which is set to be 0 or signaled by SAS.

[0097] Example 25 may include the method of example 22 and/or some other example herein, wherein the synchronization signal can be in the central six PRBs of the preamble, and be present at the beginning of the preamble, e.g., PSS at first symbol and SSS at second symbol, or PSS at second symbol and SSS at first symbol of the preamble.

[0098] Example 26 may include the method of example 22 and/or some other example herein, wherein payload information can be encoded via TBCC at one-third rate and QPSK modulation.

[0099] Example 27 may include the method of example 22 and/or some other example herein, wherein the presence detection of the preamble can be performed with RS detection. In addition, synchronization signals can help improve the presence detection performance.

[00100] Example 28 may include the method of example 22 and/or some other example herein, wherein a set of sequences can be adopted for CTS, which is independent of cell ID, and different sequences indicate different burst duration information.

[00101] Example 29 may include the method of example 28 and/or some other example herein, wherein sequences can be based on CRS/CSI- RS/DMRS/PRACH, or can be newly designed sequences.

[00102] Example 30 may include the method of example 29 and/or some other example herein, wherein there may be a gap between the preamble and following control/shared channel, to leave processing time for receiving devices for detection.

[00103] Example 31 may include the method of example 18 and/or some other example herein, wherein PDCCH can be transmitted to hold the channel.

[00104] Example 32 may include the method of example 31 and/or some other example herein, wherein PDCCH can indicate one or multiple of the following information: the current/next subframe length, the following uplink (UL) burst information (e.g., offset and duration), and a set of subframes which will be used for transmission. [00105] Example 33 may include the method of examples 31 and 32 and/or some other example herein, wherein a new DCI format can be defined for the PDCCH to carry the information mentioned in example 22.

[00106] Example 34 may include the method of examples 31 and 32 and/or some other example herein, wherein the DCI format 1C can be reused.

[00107] Example 35 may include the method of examples 31 -34 and/or some other example herein, wherein new a RNTI different from CC-RNTT can be defined to scramble the DCI.

[00108] Example 36 may include the method of example 31 and/or some other example herein, wherein the PDCCH can be transmitted in every DL subframe, or a subset of DL subframe, e.g., only the beginning N subframe (e.g., N = 2 or 3), or every other subframe.

[00109] Example 37 may include the method of example 31 and/or some other example herein, wherein eNBs from the same operator receiving the PDCCH can perform blind detection, with different hypothesis tests with respect to PDCCH overNID and scrambling of CRS/PDCCH.

[00110] Example 38 may include the method of example 31 and/or some other example herein, wherein PDCCH/CRS scrambling can be based on default cell ID, e.g., 0, or a cell ED signaled by SAS.

[00111] Example 39 may include the method of example 31 and/or some other example herein, wherein the nearby devices receiving the PDCCH defer the LBT and transmission during the duration indicated by PDCCH, which is used for transmission by the LPN that transmits the PDCCH.

[00112] Example 40 may include the method of example 13 and/or some other example herein, wherein an Enhanced Inter-Cell Interference Coordination (elCIC)-like approach can be adopted, where HPNs broadcast the muting pattern and nearby devices who receive the indication can use the muted subframes for LBT and transmission.

[00113] Example 41 may include the method of example 40 and/or some other example herein, wherein the muting pattern can be indicated as a bitmap.

[00114] Example 42 may include the method of example 40 and/or some other example herein, wherein several muting patterns can be pre-defined or indicated via SAS, and the associated index is indicated by HPNs. [00115] Example 43 may include the method of example 40 and/or some other example herein, wherein the muting granularity can be a radio frame, a subframe, or multiple consecutive subframes.

[00116] Example 44 may include the method of example 40 and/or some other example herein, wherein the indication of the muting pattern can be transmitted in every DL subframe, or in a subset of DL subframes, e.g., the beginning N DL subframes (e.g., N=2 or 3), or every other subframe.

[00117] Example 45 may include the method of example 40 and/or some other example herein, wherein PDCCH can be exploited to carry the muting pattern of HPNs.

[00118] Example 46 may include the method of example 45 and/or some other example herein, wherein the PDCCH is common cross cells, and nearby devices who receive the PDCCH can use the muted subframes for LBT and transmission.

[00119] Example 47 may include the method of example 45 and/or some other example herein, wherein a new format of DCI can be defined for the PDCCH to carry the muting information.

[00120] Example 48 may include the method of example 45 and/or some other example herein, wherein legacy DCI format, e.g., DCI format 1C, can be reused.

[00121] Example 49 may include the method of example 45 and/or some other example herein, wherein a new ΚΝΊΊ, different from CC-RNT1, can be defined to scramble the DCI.

[00122] Example 50 may include the method of example 45 and/or some other example herein, wherein eNBs from the same operator receiving the

PDCCH can perform blind detection, with different hypothesis tests with respect to cPDCCH overNID and scrambling of CRS/cPDCCH.

[00123] Example 51 may include the method of example 45 and/or some other example herein, wherein PDCCH/CRS scrambling can be based on default cell ID, e.g., 0, or cell ID signaled by SAS.

[00124] Example 52 may include the method of example 40 and/or some other example herein, wherein a set of sequences can be used to indicate the muting pattern. [00125] Example 53 may include the method of example 52 and/or some other example herein, wherein the sequences are common cross cells, and different sequences indicate different muting patterns.

[00126] Example 54 may include the method of example 52 and/or some other example herein, wherein the legacy sequence in LTE, e.g., CRS/CS1- RS/DMRS/PRACH, can be used.

[00127] Example 55 may include the method of example 52 and/or some other example herein, wherein a set of newly designed sequences can be used.

[00128] Example 56 may include the method of example 40 and/or some other example herein, wherein the muting pattern can be semi -statically configured. SAS can signal the muting pattern, based on long-term estimation of interference scenario.

[00129] Example 57 may include the method of example 56 and/or some other example herein, wherein SAS configures the muting pattern via a bitmap- based method, where N bits can be used (e.g., N=10) and HPNs mute based on the N-bit indication, with the muting pattern repeating every N subframes.

[00130] Example 58 may include the method of example 56 and/or some other example herein, wherein a set of muting patterns can be predefined, and SAS indicates the index of the muting pattern to be used.

[00131] Example 59 may include the method of examples 12-58 and/or some other example herein, wherein TJE can behavior similar as eNB following, e.g., the UE can transmit the preamble to reserve the channel after performing Cat-4 LBT, the UE receiving the cPDCCH/preamble can defer the LBT and transmission in the CTS method, or the UE receiving PDCCH indicating the muting pattern in the elCIC-like approach may perform LBT and transmission during the indicated muted duration.

[00132] Example 60 may include the method of example 59 and/or some other example herein, wherein when UE receives a CTS message, the UE still keeps monitoring the PDCCH and receiving the PDSCH if scheduled, even during the transmission time indicated by the CTS message. The UE may defer the LBT and UL transmission during the transmission time indicated by the CTS message. [00133] Example 61 is an apparatus to: identify a communication including a muting pattern indication associated with semi-static configuration by a spectrum access system (SAS); and transmit using LBT (listen before talk) during a muted subframe of unlicensed spectrum in 3.5 Ghz band responsive to the muting pattern indication.

[00134] Example 62 includes the subject matter of example 61 and/or some other example herein, wherein the muting pattern indication corresponds to a bitmap.

[00135] Example 63 includes the subject matter of any of examples 61 -62 and/or some other example herein, wherein the bitmap corresponds to N bits and high-power nodes are to mute based on N-bit indications.

[00136] Example 64 includes the subject matter of any of examples 61-63 and/or some other example herein, wherein the muting pattern indication comprises an index to specify a subset of a set of predefined muting patterns.

[00137] Example 65 may includes the subject matter of any of examples 61-64 and/or some other example herein, wherein the apparatus is a UE (user equipment) or a portion thereof, or an eNB (evolved node B) or a portion thereof.

[00138] Example 66 is an apparatus to: identify a muting pattern for unlicensed spectrum in 3.5 Ghz based on interference estimation to be semi- statically configured; and cause a muting pattern indication to be broadcast based on the muting pattern.

[00139] Example 67 may include the subject matter of example 66 and/or some other example herein, wherein the muring pattern indication is bitmap based.

[00140] Example 68 may include the subject matter of any of examples 66-67 and/or some other example herein, wherein the broadcast is to repeat every N subframes and high-power nodes are to mute based on N-bit indications.

[00141] Example 69 may include the subject matter of any of examples 66-68 and/or some other example herein, wherein the muting pattern indication comprises an index. [00142] Example 70 may include the subject matter of any of examples 66-69 and/or some other example herein, wherein the apparatus is a network device of an S AS (spectrum access system) or a portion thereof.

[00143] Example 71 is a method, comprising: identifying, or causing to be identified, a muting pattern indication associated with semi-static configuration by a spectrum access system (SAS); and performing, or causing to be performed, LBT (listen before talk) and transmission on a muted subframe of unlicensed spectrum in 3.5 Ghz band responsive to the muting partem indication.

[00144] Example 72 may include the subject matter of example 71 and/or some other example herein, wherein the muting pattern indication is identified based on a bitmap.

[00145] Example 73 may include the subject matter of any of examples 71-72 and/or some other example herein, wherein the bitmap corresponds to N bits and high-power nodes are to mute based on N-bit indications.

[00146] Example 74 may include the subject matter of any of examples 71-73 and/or some other example herein, wherein the muting pattern indication comprises an index to specify a subset of a set of predefined muting patterns.

[00147] Example 75 may include the subject matter of any of examples 71-74 and/or some other example herein, wherein the method is performed, in whole or in part, by a UE (user equipment) or a portion thereof, or an eNB (evolved node B) or a portion thereof.

[00148] Example 76 is a method, comprising: semi-statically configuring, or causing to be semi-statically configured, a muting pattern for unlicensed spectrum in 3.5 Ghz based on interference estimation; and broadcasting, or causing to be broadcast, a muting pattern indi cation to be broadcast based on the muting pattern.

[00149] Example 77 may include the subject matter of example 76 and/or some other example herein, wherein the muting pattern indication is bitmap based.

[00150] Example 78 may include the subject matter of any of examples 76-77 and/or some other example herein, wherein the broadcast is to repeat every N subframes and high-power nodes are to mute based on N-bit indications. [00151] Example 79 may include the subject matter of any of examples 76-78 and/or some other example herein, wherein the muting pattern indication comprises an index.

[00152] Example 80 may include the subject matter of any of examples 76-79 and/or some other example herein, wherein the method is performed, in whole or in part, by a network device of an S AS (spectrum access system) or a portion thereof.

[00153] Example 81 may include an apparatus comprising means to perform one or more elements of a method described in or related to any of examples 1 -80, or any other method or process described herein.

[00154] Example 82 may include one or more non-transitory computer- readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of a method described in or related to any of examples 1-80, or any other method or process described herein.

[00155] Example 83 may include an apparatus comprising logic, modules, and/or circuitry to perform one or more elements of a method described in or related to any of examples 1-80, or any other method or process described herein.

[00156] Example 84 may include a method, technique, or process as described in or related to any of examples 1-80, or portions or parts thereof.

[00157] Example 85 may include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform the method, techniques, or process as described in or related to any of examples 1-80, or portions thereof.

[00158] Example 86 may include a method of communicatirig in a wireless network as shown and described herein.

[00159] Example 87 may include a system for providing wireless communication as shown and described herein.

[00160] Example 88 may include a device for providing wireless communication as shown and described herein. [00161] Example 89 is an apparatus of a first evolved node B (eNB) operating in a communication system to resolve transmit power disparity within the communication system, the apparatus comprising: a communication interface configured to receive unlicensed channel access information for an unlicensed channel from a second eNB; and processing circuitry coupled to the

communication interface and configured to: process the unlicensed channel access information; determine an unlicensed channel usage by the second eNB based on the unlicensed channel access information; and delay use of the unlicensed channel during the unlicensed channel usage by the second eNB based on the unlicensed channel access information, wherein the unlicensed channel access information is processed, at least in part, according to a transmit power disparity on the unlicensed channel between the first eNB and the second eNB.

[00162] In Example 90, the subject matter of Example 89 optionally includes wherein the unlicensed channel access information comprises an energy detection (ED) signal detected for the unlicensed channel, wherein a first ED threshold for the first eNB to determine unlicensed channel usage by the second eNB is different than a second ED threshold for the second eNB to determine the unlicensed channel usage by the first eNB.

[00163] In Example 91, the subject matter of Example 90 optionally includes wherein the unlicensed channel is within a 3.5 GHz Citizens Broadband Radio Service (CBRS) spectrum; and wherein the ED threshold (X) for the first eNB, with the transmission power Ptx, is: X=.

[00164] In Example 92, the subject matter of any one or more of

Examples 90-91 optionally include wherein the first ED threshold is semi- statically indicated via spectrum access system (SAS) signaling.

[00165] In Example 93, the subject matter of any one or more of

Examples 89-92 optionally include wherein the unlicensed channel access information comprises a preamble transmission by the second eNB to the first eNB prior to a data transmission by the second eNB; wherein the preamble transmission indicates a duration of the data transmission.

[00166] In Example 94, the subject matter of Example 93 optionally includes wherein the preamble transmission comprises a cell-specific references signal (CRS), a demodulation reference signal (OMRS), or an unlicensed channel state information reference signal (CSI-RS); wherein the preamble transmission further indicates an expected number of downlink (DL) and uplink (UL) subframes in the data transmission; and wherein the processing circuitry is further configured to perform a blind detection of the preamble transmission.

[00167] In Example 95, the subject matter of any one or more of

Examples 93-94 optionally include-6 wherein the preamble transmission comprises a primary synchronization signal (PSS) within a first physical resource block (PRB) of the preamble transmissioa

[00168] In Example 96, the subject matter of Example 95 optionally includes wherein the preamble transmission comprises a secondary

synchronization signal (SSS) within a second PRB of the preamble transmissioa [00169] In Example 97, the subject matter of any one or more of

Examples 93-96 optionally include-6 or 8 wherein the preamble transmission is encoded via tail-biting convolutional codes (TBCC) at one-third rate and with quadrature phase-shift key (QPSK) modulation.

[00170] In Example 98, the subject matter of any one or more of

Examples 93-97 optionally include-6 or 8 wherein the processing circuitry is configured to detect the preamble transmission using reference signal (RS) detection

[00171] In Example 99, the subject matter of any one or more of

Examples 93-98 optionally include-6 or 8 wherein the processing circuitry is configured to sequence detection to detect signals; wherein different sequences in a sequence set are used to indicate the duration of the data transmission.

[00172] In Example 100, the subject matter of any one or more of Examples 89-99 optionally include wherein the unlicensed channel access information comprises information from a physical downlink control unlicensed channel (PDCCH) transmission.

[00173] In Example 101 , the subject matter of Example 100 optionally includes wherein the processing circuitry is configured to detect the PDCCH transmission from the second eNB by blind detection of the PDCCH over a network interface device (NID) with hypothesis over scrambling for cell-specific reference signal (CRS) or cell PDCCH (cPDCCH). [00174] In Example 102, the subject matter of any one or more of Examples 100-101 optionally include wherein the processing circuitry is configured to detect the PDCCH transmission where the PDCCH is scrambled using a default cell identifier (ID) or a cell ID signaled by SAS.

[00175] In Example 103, the subject matter of any one or more of Examples 89-102 optionally include wherein the unlicensed channel access information comprises a muting pattern broadcast; wherein the processing circuitry is further configured to perform a listen before talk (LBT) operation in response to the unlicensed channel access informatioa

[00176] Example 104 is a computer-readable storage device comprising instructions mat, when executed by one or more processors of a first evolved node B (eNB), cause the first eNB to: process unlicensed channel access information received from a second eNB; determine unlicensed channel usage by the second eNB based on the unlicensed channel access information; and manage use of an unlicensed channel by the first eNB during the unlicensed channel usage by the second eNB based on the unlicensed channel access information; wherein the unlicensed channel usage by the first eNB is managed, at least in part, based on a transmit power disparity on the unlicensed channel between the first eNB and the second eNB.

[00177] In Example 1 OS, the subject matter of Example 104 optionally includes wherein the instructions further cause the first eNB to perform a listen before talk (LBT) operation in response to the unlicensed channel access information prior to using the unlicensed channel during the unlicensed channel usage by the second eNB.

[00178] In Example 106, the subject matter of any one or more of Examples 104-105 optionally include wherein the unlicensed channel access information comprises an energy detection (ED) signal detected for the unlicensed channel, wherein a first ED threshold for the first eNB to determine unlicensed channel usage by the second eNB is different than a second ED threshold for the second eNB to determine unlicensed channel usage by the first eNB; wherein the unlicensed channel is within a 3.5 GHz Citizens Broadband Radio Service (CBRS) spectrum; and wherein an ED threshold X for the first eNB, with the transmission power Ptx, is: X= [00179] Another example is an apparatus of a second evolved node B (eNB) operating in a communication system to resolve transmit power disparity within the communication system, the apparatus comprising: a communication interface configured to transmit unlicensed channel access information for an unlicensed channel to a first eNB; and processing circuitry coupled to the communication interface and configured to: process data for a data transmission; determine unlicensed channel usage for the unlicensed channel associated with the data transmission; generate the unlicensed channel access information based on the unlicensed channel usage and a transmit power disparity between the second eNB and the first eNB; initiate transmission of the unlicensed channel access information; and initiate transmission of the data transmission following transmission of the unlicensed channel access information.

[00180] In Example 107, the subject matter of Example undefined optionally includes wherein the unlicensed channel access information comprises a preamble transmission by the second eNB to the first eNB prior to a data transmission by the second eNB; and wherein the preamble transmission indicates a duration of the data transmission.

[00181] In Example 108, the subject matter of Example 107 optionally includes wherein the preamble transmission comprises a cell-specific references signal (CRS), a demodulation reference signal (DMRS), or an unlicensed channel state information reference signal (CSI-RS); wherein the preamble transmission further indicates an expected number of downlink (DL) and uplink (UL) subframes in the data transmission.

[00182] Example 109 is a computer-readable storage device comprising instructions mat, when executed by one or more processors of a second evolved node B (eNB), cause the second eNB to: process data for a data transmission on an unlicensed channel; determine unlicensed channel usage for the unlicensed channel associated with the data transmission; generate unlicensed channel access information based on the unlicensed channel usage and a transmit power disparity between the second eNB and a first eNB within a threshold distance of the second eNB; initiate transmission of the unlicensed channel access information; and initiate transmission of the data transmission on the unlicensed channel following transmission of the unlicensed channel access information. [00183] In Example 110, the subject matter of Example 109 optionally includes wherein generating the unlicensed channel access information comprises encoding the unlicensed channel access information using tail-biting convolutional codes (TBCC) at one-third rate and with quadrature phase-shift key (QPSK) modulation.

[00184] In Example 111, the subject matter of any one or more of Examples 109-110 optionally include wherein the unlicensed channel access information comprises a primary synchronization signal (PSS) within a first physical resource block (PRB) of the preamble transmission and a secondary synchronization signal (SSS) within a second PRB of the preamble transmission.

[00185] Example 112 is an apparatus of a first evolved node B (eNB) operating in a communication system to resolve transmit power disparity within the communication system, the apparatus comprising: means for receiving unlicensed channel access information for an unlicensed channel from a second eNB; and means for processing the unlicensed channel access information; means for determining an unlicensed channel usage by the second eNB based on the unlicensed channel access information; and means for delaying use of the unlicensed channel during the unlicensed channel usage by the second eNB based on the unlicensed channel access information, wherein the unlicensed channel access information is processed, at least in part, according to a transmit power disparity on the unlicensed channel between the first eNB and the second eNB.

[00186] In Example 113, the subject matter of Example 112 optionally includes wherein the unlicensed channel access information comprises an energy detection (ED) signal detected for the unlicensed channel, wherein a first ED threshold for the first eNB to determine unlicensed channel usage by the second eNB is different than a second ED threshold for the second eNB to determine the unlicensed channel usage by the first eNB.

[00187] In Example 114, the subject matter of Example 113 optionally includes wherein the unlicensed channel is within a 3.5 GHz Citizens Broadband Radio Service (CBRS) spectrum; and wherein the ED threshold (X) for the first eNB, with the transmission power Ptx, is: X= 28. The apparatus of claim 26 wherein Ihe first ED threshold is send-statically indicated via spectrum access system (SAS) signaling.

[00188] In Example 115, the subject matter of any one or more of Examples 112-114 optionally include wherein Ihe unlicensed channel access information comprises a preamble transmission by the second eNB to the first eNB prior to a data transmission by the second eNB; wherein ihe preamble transmission indicates a duration of the data transmission.

[00189] In Example 116, Ihe subject matter of Example 115 optionally includes wherein the preamble transmission comprises a cell-specific references signal (CRS), a demodulation reference signal (DMRS), or an unlicensed channel state information reference signal (CSI-RS); and wherein the preamble transmission further indicates an expected number of downlink (DL) and uplink (UL) subframes in the data transmission.

[00190] In Example 117, Ihe subject matter of any one or more of Examples 112-116 optionally include-30 further comprising: means to perform a blind detection of the preamble transmission.

[00191] In Example 118, the subject matter of any one or more of Examples 112-117 optionally include-30 further comprising means for detecting the PDCCH transmission from the second eNB by blind detection of the PDCCH over a network interface device (NID) with hypothesis over scrambling for cell- specific reference signal (CRS) or cell PDCCH (cPDCCH).

[00192] In Example 119, the subject matter of Example 118 optionally includes further comprising means for detecting the PDCCH transmission where the PDCCH is scrambled using a default cell identifier (ID) or a cell ID signaled by SAS.

[00193] In Example 120, the subject matter of any one or more of Examples 112-119 optionally include wherein the unlicensed channel access information comprises a muting pattern broadcast

[00194] In Example 121 , Ihe subject matter of Example 120 optionally includes further comprising: means for performing a listen before talk (LBT) operation in response to the unlicensed channel access ^formation

[00195] Example 122 is a method for communications on an unlicensed channel, the method comprising: processing unlicensed channel access information received from a second eNB; determining unlicensed channel usage by the second eNB based on the unlicensed channel access information; and managing use of an unlicensed channel by the first eNB during the unlicensed channel usage by the second eNB based on the unlicensed channel access information; wherein the unlicensed channel usage by the first eNB is managed, at least in part, based on a transmit power disparity on the unlicensed channel between the first eNB and the second eNB.

[00196] Example 123 is The method claim 36 wherein the instructions further cause the first eNB to perform a listen before talk (LBT) operation in response to the unlicensed channel access information prior to using the unlicensed channel during the unlicensed channel usage by the second eNB.

[00197] In Example 124, the subject matter of any one or more of Examples 122-123 optionally include wherein the unlicensed channel access information comprises an energy detection (ED) signal detected for the unlicensed channel, wherein a first ED threshold for the first eNB to determine unlicensed channel usage by the second eNB is different than a second ED threshold for the second eNB to determine unlicensed channel usage by the first eNB; wherein the unlicensed channel is within a 3.3 GHz Citizens Broadband Radio Service (CBRS) spectrum; and wherein an ED threshold X for the first eNB, with the transmission power Ptx, is: X=

[00198] Another such example is an apparatus of a second evolved node B (eNB) operating in a communication system to resolve transmit power disparity within the communication system, the apparatus comprising: means for transmitting unlicensed channel access information for an unlicensed channel to a first eNB; means for processing data for a data transmission; means for determining unlicensed channel usage for the unlicensed channel associated with the data transmission; means for generating the unlicensed channel access information based on the unlicensed channel usage and a transmit power disparity between the second eNB and the first eNB; means for transmission of the unlicensed channel access information; and means for transmission of the data transmission following transmission of the unlicensed channel access information. [00199] In Example 125, the subject matter of Example undefined optionally includes wherein the unlicensed channel access information comprises a preamble transmission by the second eNB to the first eNB prior to a data transmission by the second eNB; and wherein the preamble transmission indicates a duration of the data transmission.

[00200] In Example 126, the subject matter of Example 12S optionally includes wherein the preamble transmission comprises a cell-specific references signal (CRS), a demodulation reference signal (OMRS), or an unlicensed channel state information reference signal (CSI-RS); wherein the preamble transmission further indicates an expected number of downlink (DL) and uplink (UL) subframes in the data transmission.

[00201] Example 127 is a method for communication on shared unlicensed frequencies comprising: processing data for a data transmission on an unlicensed channel; determining unlicensed channel usage for the unlicensed channel associated with the data transmission; generating unlicensed channel access information based on the unlicensed channel usage and a transmit power disparity between the second eNB and a first eNB within a threshold distance of the second eNB; initiating transmission of the unlicensed channel access information; and initiating transmission of the data transmission on the unlicensed channel following transmission of the unlicensed channel access information.

[00202] In Example 128, me subject matter of Example 127 optionally includes wherein generating the unlicensed channel access information comprises encoding the unlicensed channel access information using tail-biting convolutional codes (TBCC) at one-third rate and with quadrature phase-shift key (QPSK) modulation.

[00203] In Example 129, the subject matter of any one or more of Examples 127-128 optionally include wherein the unlicensed channel access information comprises a primary synchronization signal (PSS) within a first physical resource block (PRB) of the preamble transmission and a secondary synchronization signal (SSS) within a second PRB of the preamble transmission. [00204] Example 130 is a computer readable storage medium comprising instructions that, when executed by one or more processors of a device, cause the device to perform operations of any method described above.

[00205] The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. Additionally, other example embodiments may include any examples described above with the individual operations or device elements repeated or ordered with intervening elements or operations in any functional order.

[00206] FIG. 6 shows an example UE 600. The TJE 600 may be an implementation of the UE 102, or any device described herein. The UE 600 can include one or more antennas 608 configured to communicate with a transmission station, such as a base station (BS), an eNB, or another type of wireless wide area network (WW AN) access point. The UE 600 can be configured to communicate using at least one wireless communication standard including 3GPP LTE, WiMAX®, High-Speed Packet Access (HSPA),

Bluetooth, and Wi-Fi®. The UE 600 can communicate using separate antennas for each wireless communication standard or shared antennas for multiple wireless communication standards. The UE 600 can communicate in a WLAN, a wireless personal area network (WPAN), and/or a WW AN.

[00207] FIG. 6 also shows a microphone 620 and one or more speakers 612 that can be used for audio input and output to and from the UE 600. A display screen 604 can be a liquid crystal display (LCD) screen, or another type of display screen such as an organic light-emitting diode (OLED) display. The display screen 604 can be configured as a touch screen. The touch screen can use capacitive, resistive, or another type of touch-screen technology. An application processor 614 and a graphics processor 618 can be coupled to an internal memory 616 to provide processing and display capabilities. A non-volatile memory port 610 can also be used to provide data I/O options to a user. The non-volatile memory port 610 can also be used to expand the memory capabilities of the UE 600. A keyboard 606 can be integrated with the UE 600 or wirelessly connected to the UE 600 to provide additional user input. A virtual keyboard can also be provided using the touch screen. A camera 622 located on the front (display screen 604) side or the rear side of the UE 600 can also be integrated into a housing 602 of the UE 600.

[00208] FIG. 7 is a block diagram illustrating an example computer system machine 700 upon which any one or more of the methodologies herein discussed can be run, and which may be used to implement the eNB 104, the UE 102, or any other device described herein. In various alternative embodiments, the computer system machine 700 operates as a standalone device or can be connected (e.g., networked) to other machines. In a networked deployment, the computer system machine 700 can operate in the capacity of either a server or a client machine in server-client network environments, or it can act as a peer machine in peer-to-peer (or distributed) network environments. The computer system machine 700 can be a personal computer (PC) that may or may not be portable (e.g., a notebook or a netbook), a tablet, a set-top box (STB), a gaming console, a Personal Digital Assistant (PDA), a mobile telephone or smartphone, a web appliance, a network router, a network switch, a network bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by mat machine. Further, while only a single computer sy stem machine 700 is illustrated, the term ''machine" shall also be taken to include any collection of machines mat individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

[00209] The exampl e computer system machine 700 includes a processor 702 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), or both), a main memory 704, and a static memory 706, which communicate with each other via an interconnect 708 (e.g., a link, a bus, etc.). The computer system machine 700 can further include a video display device 710, an alphanumeric input device 712 (e.g., a keyboard), and a user interface (UI) navigation device 714 (e.g., a mouse). In one embodiment, the video display device 710, alphanumeric input device 712, and UI navigation device 714 are a touch screen display. The computer system machine 700 can additionally include a mass storage device 716 (e.g., a drive unit), a signal generation device 718 (e.g., a speaker), an output controller 732, a power management controller 734, a network interface device 720 (which can include or operably communicate with one or more antennas 730, transceivers, or other wireless communications hardware), and one or more sensors 728, such as a GPS sensor, compass, location sensor, accelerometer, or other sensor.

[00210] The mass storage device 716 includes a machine-readable medium 722 on which is stored one or more sets of data structures and instructions 724 (e.g., software) embodying or utilized by any one or more of the methodologies or functions described herein. The instructions 724 can also reside, completely or at least partially, within the main memory 704, static memory 706, and/or processor 702 during execution thereof by the computer system machine 700, with the main memory 704, the static memory 706, and the processor 702 also constituting machine-readable media

[00211] While the machine-readable medium 722 is illustrated in an example embodiment to be a single medium, the term ''machine-readable medium" can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more instructions 724. The term ''machine-readable medium" shall also be taken to include any tangible medium that is capable of storing, encoding, or carrying instructions (e.g., instructions 724) for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure, or that is capable of storing, encoding, or carrying data structures utilized by or associated with such instructions.

[00212] The instructions 724 can further be transmitted or received over a communications network 726 using a transmission medium via the network interface device 720 utilizing any one of a number of well-known transfer protocols (e.g., hypertext transfer protocol (HTTP)). The term "transmission medium" shall be taken to include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine, and includes digital or analog communications signals or other intangible media to facilitate communication of such software.

[00213] Various techniques, or certain aspects or portions thereof, may take the form of program code (i.e., instructions 724) embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, non-transitory computer-readable storage media, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the various techniques. In the case of program code execution on programmable computers, the computer may include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. The volatile and non-volatile memory and/or storage elements may be a Random Access Memory (RAM), Erasable Programmable Read-Only Memory (EPROM), flash drive, optical drive, magnetic hard drive, or other medium for storing electronic data. The eNB and UE may also include a transceiver module, a counter module, a processing module, and/or a clock module or timer module. One or more programs mat may implement or utilize the various techniques described herein may use an application programming interface (API), reusable controls, and the like. Such programs may be implemented in a high-level procedural or object- oriented programming language to communicate with a computer system However, the program(s) may be implemented in assembly or machine language, if desired In any case, the language may be a compiled or interpreted language, and combined with hardware implementations.

[00214] Various embodiments may use 3GPP LTE/LTE-A, IEEE 602.11, and Bluetooth communication standards. Various alternative embodiments may use a variety of other WWAN, WLAN, and WPAN protocols and standards in connection with the techniques described herein. These standards include, but are not limited to, other standards from 3GPP (e.g., HSPA+, UMTS), IEEE 702.16 (e.g., 702.16p), or Bluetooth (e.g., Bluetooth 7.0, or like standards defined by the Bluetooth Special Interest Group) standards families. Other applicable network configurations can be included within the scope of the presently described communication networks. It will be understood that communications on such communication networks can be facilitated using any number of personal area networks (PANs), local area networks (LANs), and wide area networks (WANs), using any combination of wired or wireless transmission mediums [00215] Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. FIG. 8 illustrates components of aUE 800 in accordance with some embodiments. At least some of the components shown may be used in the UE 102 (or eNB 104) shown in FIG. 1. The UE 800 and other components may be configured to use the synchronization signals as described herein. The UE 800 may be one of the UEs 102 shown in FIG. 1 and may be a stationary, non-mobile device or may be a mobile device. In some embodiments, the UE 800 may include application circuitry 802, baseband circuitry 804, Radio Frequency (RF) circuitry 806, front- end module (FEM) circuitry 808, and one or more antennas 810, coupled together at least as shown. At least some of the baseband circuitry 804, RF circuitry 806, and FEM circuitry 808 may form a transceiver. In some embodiments, other network elements, such as the eNB 104, may contain some or all of the components shown in FIG. 8. Other of the network elements, such as the MME 122, may contain an interface, such as the SI interface, to communicate with the eNB 104 over a wired connection regarding the UE 800.

[00216] The application circuitry 802 may include one or more application processors. For example, the application circuitry 802 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors) 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 UE 800.

[00217] The baseband circuitry 804 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 804 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 806 and to generate baseband signals for a transmit signal path of the RF circuitry 806. The baseband circuitry 804 may interface with the application circuitry 802 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 806. For example, in some embodiments, the baseband circuitry 804 may include a second generation (2G) baseband processor 804a, third generation (3G) baseband processor 804b, fourth generation (4G) baseband processor 804c, and/or other baseband processor(s) 804d for other existing generations, generations in development, or generations to be developed in the future (e.g., fifth generation (SG), etc.). The baseband circuitry 804 (e.g., one or more of the baseband processors 804a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 806. 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 804 may include FFT, precoding, and/or constellation mapping/ demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 804 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.

[00218] In some embo(liments, the baseband circuitry 804 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 804e of the baseband circuitry 804 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 804 may include one or more audio digital signal processors) (DSPs) 804f. The audio DSP(s) 804f may be or include elements for compression/decompressi on and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry 804 may be suitably combined in a single chip or 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 804 and the application circuitry 802 may be implemented together, such as, for example, on a system on a chip (SOC).

[00219] In some embodiments, the baseband circuitry 804 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 804 may support communication with an EUTRAN and/or other wireless metropolitan area networks (WMAN), a WLAN, or a WP AN. Embodiments in which the baseband circuitry 804 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. In some embodiments, the UE 800 can be configured to operate in accordance with communication standards or other protocols or standards, including IEEE 602.16 wireless technology (WiMax®), IEEE 602.11 wireless technology (Wi-Fi®) including IEEE 602.11 ad, which operates in the 70 GHz millimeter wave spectrum, or various other wireless technologies such as global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE radio access network (GERAN), universal mobile telecommunications system (UMTS), UMTS terrestrial radio access network (UTRAN), or other 2G, 3G, 4G, SG, etc. technologies either already developed or to be developed.

[00220] The RF circuitry 806 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 806 may include switches, filters, amplifiers, etc., to facilitate the communication with the wireless network. The RF circuitry 806 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 808 and provide baseband signals to the baseband circuitry 804. The RF circuitry 806 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 804 and provide RF output signals to the FEM circuitry 808 for transmission.

[00221] In some embodiments, the RF circuitry 806 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 806 may include mixer circuitry 806a, amplifier circuitry 806b, and filter circuitry 806c. The transmit signal path of the RF circuitry 806 may include the filter circuitry 806c and the mixer circuitry 806a. The RF circuitry 806 may also include synthesizer circuitry 806d for synthesizing a frequency for use by the mixer circuitry 806a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 806a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 808 based on the synthesized frequency provided by the synthesizer circuitry 806cL The amplifier circuitry 806b may be configured to amplify the down-converted signals, and the filter circuitry 806c 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 804 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, the mixer circuitry 806a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[00222] In some embodiments, the mixer circuitry 806a of the transmit signal path may be configured to up-con vert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 806d to generate RF output signals for the FEM circuitry 808. The baseband signals may be provided by the baseband circuitry 804 and may be filtered by the filter circuitry 806c. The filter circuitry 806c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[00223] In some embodiments, the mixer circuitry 806a of the receive signal path and the mixer circuitry 806a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 806a of the receive signal path and the mixer circuitry 806a 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 806a of the receive signal path and the mixer circuitry 806a of the transmit signal path may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 806a of the receive signal path and the mixer circuitry 806a of the transmit signal path may be configured for superheterodyne operation.

[00224] 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 806 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 804 may include a digital baseband interface to communicate with the RF circuitry 806.

[00225] In some dual-mode embodiments, a separate radio integrated circuit (IC) circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[00226] In some embodiments, the synthesizer circuitry 806d 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, the synthesizer circuitry 806d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[00227] The synthesizer circuitry 806d may be configured to synthesize an output frequency for use by the mixer circuitry 806a ofthe RF circuitry 806 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 806d may be a fractional N/N+l synthesizer.

[00228] 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 804 or the application circuitry 802 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a lookup table based on a channel indicated by the application circuitry 802.

[00229] The synthesizer circuitry 806d of the RF circuitry 806 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.

[00230] In some embodiments, the synthesizer circuitry 806d 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 aLO frequency (ILO). In some embodiments, the RF circuitry 806 may include an IQ/polar converter.

[00231] The FEM circuitry 808 may include a receive signal path, which may include circuitry configured to operate on RF signals received from the one or more antennas 810, amplify the received signals, and provide the amplified versions of the received signals to the RF circuitry 806 for further processing. The FEM circuitry 808 may also include a transmit signal path, which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 806 for transmission by one or more of the one or more antennas 810.

[00232] In some embodiments, the FEM circuitry 808 may include a Tx/Rx switch to switch between transmit mode and receive mode operation. The FEM circuitry 808 may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry 808 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 806). The transmit signal path of the FEM circuitry 808 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by the RF circuitry 806), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 810).

[00233] In some embodiments, the UE 800 may include additional elements such as, for example, a memory/storage, display, camera, sensor, and/or input/output (I/O) interface as described in more detail below. In some embodiments, the UE 800 described herein may be part of a portable wireless communication device, such as a PDA, a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or another device that may receive and/or transmit information wirelessly. In some embodiments, the UE 800 may include one or more user interlaces designed to enable user interaction with the system and/or peripheral component interfaces designed to enable peripheral component interaction with the system For example, the UE 800 may include one or more of a keyboard, a keypad, a touchpad, a display, a sensor, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, a power supply interface, one or more antennas, a graphics processor, an application processor, a speaker, a microphone, and other I/O components. The display may be an LCD or light- emitting diode (LED) screen including a touch screen. The sensor may include a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite.

[00234] The antennas 810 may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, the antennas 810 may be effectively separated to benefit from spatial diversity and the different channel

characteristics that may result

[00235] Although the UE 800 is illustrated 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, such as processing elements including DSPs, and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs), and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements.

[00236] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g. , hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client, or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a communication device-readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

[00237] Accordingly, the term "module" is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using software, the general -purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time. [00238] While the communication device-readable medium is illustrated as a single medium, the term "communication device-readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions.

[00239] The term "communication device-readable medium" may include any medium mat is capable of storing, encoding, or carrying instructions for execution by the communication device and that cause the communication device to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding, or carrying data structures used by or associated with such instructions. Non-limiting communication device-readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of communication device-readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., EPROM, Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; RAM; and CD-ROM and DVD-ROM disks. In some examples, communication device-readable media may include non-transitory communication device-readable media In some examples, communication device-readable media may include communication device- readable media that is not a transitory propagating signal.

[00240] The instructions may further be transmitted or received over a communications network using a transmission medium via a network interface device utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), HTTP, etc.). Example communication networks may include a LAN, a WAN, a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone Service (POTS) networks, wireless data networks (e.g., IEEE 602.11 family of standards known as Wi-Fi®, IEEE 602.16 family of standards known as WiMAX®), IEEE 602.15.4 family of standards, an LTE family of standards, a Universal Mobile Telecommunicarj ons System (UMTS) family of standards, or peer-to-peer (P2P) networks, among others. In an example, the network interface device may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network. In an example, the network interface device may include a plurality of antennas to wirelessly communicate using single-input multiple-output (SEMO), MIMO, or multiple- input single-output (MISO) techniques. In some examples, the network interface device may wirelessly communicate using Multiple User MIMO techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the communication device, and includes digital or analog communications signals or other intangible media to facilitate communication of such software.

[00241] Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include readonly memory (ROM), RAM, magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device.

[00242] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The

accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

[00243] Such embodiments of the subject matter may be referred to herein, individually and/or collectively, by the term "embodiments" merely for convenience and without intending to voluntarily limit the scope of this application to any single inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various

embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

[00244] In mis document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In mis document, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "mcluding" and "comprising" are open-ended; that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim is still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," ''third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[00245] The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment

Claims

CLAIMS What is claimed is:

1. An apparatus of a first evolved node B (eNB) operating in a communication system to resolve transmit power disparity within the communication system, the apparatus comprising:

a communication interface configured to receive unlicensed channel access information for an unlicensed channel from a second eNB; and

processing circuitry coupled to the communication interface and configured to:

process the unlicensed channel access information;

determine an unlicensed channel usage by the second eNB based on the unlicensed channel access information; and

delay use of me unlicensed channel during the unlicensed channel usage by the second eNB based on the unlicensed channel access information,

wherein the unlicensed channel access information is processed, at least in part, according to a transmit power disparity on the unlicensed channel between the first eNB and the second eNB.

2. The apparatus of claim 1 wherein the unlicensed channel access information comprises an energy detection (ED) signal detected for the unlicensed channel, wherein a first ED threshold for the first eNB to determine unlicensed channel usage by the second eNB is different than a second ED threshold for the second eNB to determine the unlicensed channel usage by the first eNB.

3. The apparatus of claim 2 wherein the unlicensed channel is within a 3.5 GHz Citizens Broadband Radio Service (CBRS) spectrum; and wherein the ED threshold (X) for the first eNB, with the transmission power Ptx, is: X= - 72 + (23 + 10 · log10(BWMHz / 20MHz) -P_TX)_dBm

4. The apparatus of claim 2 wherein the first ED threshold is semi- statically indicated via spectrum access system (SAS) signaling.

5. The apparatus of claim 1 wherein the unlicensed channel access information comprises a preamble transmission by the second eNB to the first eNB prior to a data transmission by the second eNB;

wherein the preamble transmission indicates a duration of the data transmission.

6. The apparatus of claim 5 wherein the preamble transmission comprises a cell-specific references signal (CRS), a demodulation reference signal (DMRS), or an unlicensed channel state information reference signal (CS1-RS);

wherein the preamble transmission further indicates an expected number of downlink (DL) and uplink (UL) subframes in the data transmission; and wherein the processing circuitry is further configured to perform a blind detection of the preamble transmission.

7. The apparatus of claims 5-6 wherein the preamble transmission comprises a primary synchronization signal (PSS) within a first physical resource block (PRB) of the preamble transmissioa

8. The apparatus of claim 7 wherein the preamble transmission comprises a secondary synchronization signal (SSS) within a second PRB of the preamble transmissioa

9. The apparatus of claims 5-6 or 8 wherein the preamble transmission is encoded via tail-biting convolutional codes (TBCC) at one-third rate and with quadrature phase-shift key (QPSK) modulation.

10. The apparatus of claims 5-6 or 8 wherein the processing circuitry is configured to detect the preamble transmission using reference signal (RS) detection.

11. The apparatus of claims 5-6 or 8 wherein the processing circuitry is configured to sequence detection to detect signals;

wherein different sequences in a sequence set are used to indicate the duration of the data transmissioa

12. The apparatus of claim 1 wherein the unlicensed channel access information comprises information from a physical downlink control unlicensed channel (PDCCH) transmissioa

13. The apparatus of claim 12 wherein the processing circuitry is configured to detect the PDCCH transmission from me second eNB by blind detection of the PDCCH over a network interface device (NID) with hypothesis over scrambling for cell-specific reference signal (CRS) or cell PDCCH (cPDCCH).

14. The apparatus of claim 12 wherein the processing circuitry is configured to detect the PDCCH transmission where the PDCCH is scrambled using a default cell identifier (ID) or a cell ID signaled by SAS.

15. The apparatus of claim 1 wherein the unlicensed channel access information comprises a muting pattern broadcast;

wherein the processing circuitry is further configured to perform a listen before talk (LBT) operation in response to the unlicensed channel access information.

16. A computer-readable storage device comprising instructions mat, when executed by one or more processors of a first evolved node B (eNB), cause the first eNB to:

process unlicensed channel access information received from a second eNB;

determine unlicensed channel usage by the second eNB based on the unlicensed channel access information; and

manage use of an unlicensed channel by the first eNB during the unlicensed channel usage by the second eNB based on the unlicensed channel access information;

wherein the unlicensed channel usage by the first eNB is managed, at least in part, based on a transmit power disparity on the unlicensed channel between the first eNB and the second eNB.

17. The computer-readable storage device of claim 16 wherein the instructions further cause the first eNB to perform a listen before talk (LBT) operation in response to the unlicensed channel access information prior to using the unlicensed channel during the unlicensed channel usage by the second eNB.

18. The computer-readable storage device of claim 16 wherein the unlicensed channel access information comprises an energy detection (ED) signal detected for the unlicensed channel, wherein a first ED threshold for the first eNB to determine unlicensed channel usage by the second eNB is different than a second ED threshold for the second eNB to determine unlicensed channel usage by the first eNB;

wherein the unlicensed channel is within a 3.5 GHz Citizens Broadband Radio Service (CBRS) spectrum; and

wherein an ED threshold X for the first eNB, with the transmission power Ptx, is:

19. An apparatus of a second evolved node B (eNB) operating in a communication system to resolve transmit power disparity within the communication system, the apparatus comprising:

a communication interface configured to transmit unlicensed channel access information for an unlicensed channel to a first eNB; and processing circuitry coupled to the communication interface and configured to:

process data for a data transmission;

determine unlicensed channel usage for the unlicensed channel associated with the data transmission;

generate the unlicensed channel access information based on the unlicensed channel usage and a transmit power disparity between the second eNB and the first eNB;

initiate transmission of the unlicensed channel access information; and

initiate transmission of the data transmission following transmission of the unlicensed channel access information.

20. The apparatus of claim 19 wherein the unlicensed channel access information comprises a preamble transmission by the second eNB to the first eNB prior to a data transmission by the second eNB; and

21. The apparatus of claim 20 wherein the preamble transmission comprises a cell-specific references signal (CRS), a demodulation reference signal (DMRS), or an unlicensed channel state information reference signal (CSI-RS);

wherein the preamble transmission further indicates an expected number of downlink (DL) and uplink (UL) subframes in the data transmission

22. A computer-readable storage device comprising instructions that, when executed by one or more processors of a second evolved node B (eNB), cause the second eNB to:

process data for a data transmission on an unlicensed channel; determine unlicensed channel usage for me unlicensed channel associated with the data transmission;

generate unlicensed channel access information based on the unlicensed channel usage and a transmit power disparity between the second eNB and a first eNB within a threshold distance of the second eNB;

initiate transmission of the unlicensed channel access information; and

initiate transmission of the data transmission on the unlicensed channel following transmission of the unlicensed channel access information.

23. The computer-readable storage device of claim 22 wherein generating the unlicensed channel access information comprises encoding the unlicensed channel access information using tail-biting convolutional codes (TBCC) at one-third rate and with quadrature phase-shift key (QPSK) modulation.

24. The computer-readable storage device of claim 22 wherein the unlicensed channel access information comprises a primary synchronization signal (PSS) within a first physical resource block (PRB) of the preamble transmission and a secondary synchronization signal (SSS) within a second PRB of the preamble transmission.