EA043472B1 - METHOD AND DEVICE FOR DETECTING SYNCHRONIZATION INFORMATION IN AN UNLICENSED RANGE OF THE RADIO FREQUENCY SPECTRUM WHEN IMPLEMENTING WIRELESS COMMUNICATIONS - Google Patents

Description

This application claims the benefit of U.S. Provisional Application No. 62/109504, entitled TIMING INFORMATION FOR DISCOVERY IN UNLICENSED SPECTRUM, filed Jan. 29, 2015, and U.S. Patent Application No. 15/009730, entitled TIMING INFORMATION FOR DISCOVERY IN UNLICENSED SPECTRUM, filed Jan. 28, 2015. 16 g., both applications assigned to the assignee of this agreement and both applications are expressly incorporated herein by reference in their entirety.

State of the art

Aspects of the subject matter of the present invention relate generally to telecommunications and, in particular, to methods for transmitting and receiving synchronization signals over an unlicensed range of the radio frequency spectrum.

A wireless communications network can be deployed to provide various types of services (eg, voice, data services, multimedia, and so on) to users within the network's coverage area. In some implementations, one or more access points (eg, corresponding to different cells) provide wireless connectivity to access terminals (eg, cellular phones) that operate within the coverage area of the access point(s). In some implementations, peer devices provide a wireless connection to communicate with each other.

Communication between devices on a wireless network may be subject to radio interference. When a first network device communicates with a second network device, radio frequency (RF) energy from a nearby device may interfere with the second network device's reception of signals. For example, a Long Term Evolution (LTE) device operating in an unlicensed RF band that is also used by a Wi-Fi device may experience significant interference from the Wi-Fi device and/or may cause significant interference to the Wi-Fi device.

Some communication methods may enable communication between a base station and a user equipment (UE) over an unlicensed radio frequency spectrum band or over other radio frequency spectrum bands (eg, a licensed radio frequency spectrum band and/or an unlicensed radio frequency spectrum band) of a cellular network. As data traffic increases on cellular networks that use licensed radio spectrum, offloading at least some of the data traffic into unlicensed radio spectrum may provide the cellular operator with opportunities to increase data throughput. Unlicensed radio spectrum can also provide service in areas where access to licensed radio spectrum is not available.

Some wireless networks may not allow certain transmission procedures over unlicensed spectrum. As such, the UE may not be able to correctly receive and determine timing information for the network entity and/or cell. As a result, the UE may be unable to properly connect to the network entity and/or cell. Therefore, improvements in discovery and synchronization procedures may be required.

The essence of the invention

The following is a summary of one or more aspects to provide a basic understanding of such aspects. This summary is not a comprehensive overview of all aspects covered and is not intended to identify key or particularly important elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented below.

In accordance with one aspect, the present method relates to detecting timing information in wireless communications. Aspects described include the implementation of monitoring on a user equipment (UE) over an unlicensed range of the radio frequency spectrum for a detection signal from a network entity. The described aspects further include receiving a discovery signal during a subframe from a network entity. The described aspects further include determining the location of the current subframe of the network entity based on the discovery signal, wherein the discovery signal includes timing information corresponding to the location of the current subframe.

In another aspect, a computer-readable medium stores computer executable code related to detecting timing information in wireless communications. The described aspects further include code for monitoring the UE over an unlicensed range of the radio frequency spectrum for a detection signal from a network entity. The described aspects further include code for receiving an acquisition signal during a subframe from a network entity. The described aspects further include code for determining the location of a current subframe of a network entity based on a discovery signal, wherein the discovery signal includes timing information corresponding to the location of the current subframe.

In other aspects, the present apparatus relates to detecting timing information in wireless communications. The aspects described include a mechanism for implementing

- 1 043472 monitoring on the UE over an unlicensed range of the radio frequency spectrum for a detection signal from a network entity. The described aspects further include a mechanism for receiving a discovery signal during a subframe from a network entity. The described aspects further include a mechanism for determining the location of a current subframe of a network entity based on a discovery signal, wherein the discovery signal includes timing information corresponding to the location of the current subframe.

In a further aspect, the present apparatus relates to detecting timing information in wireless communications. Aspects described include a memory configured to store data and one or more processors communicatively coupled to the memory, wherein the one or more processors and memory are configured to monitor the UE over an unlicensed band of the radio frequency spectrum for a detection signal from a network entity. The described aspects further receive a discovery signal during a subframe from the network entity. The described aspects further determine the location of the current subframe of the network entity based on the discovery signal, wherein the discovery signal includes timing information corresponding to the location of the current subframe.

In another aspect, the present method relates to transmitting timing information in wireless communications. Aspects described include establishing, at the network entity, timing information for the discovery signal, wherein the timing information corresponds to the location of a current subframe of the network entity. The described aspects further include transmitting an acquisition signal during a subframe over an unlicensed band of the radio frequency spectrum to the UE.

In additional aspects, the present computer-readable medium stores computer executable code related to transmitting timing information in wireless communications. The described aspects include code for establishing, on a network entity, timing information for a discovery signal, wherein the timing information corresponds to the location of a current subframe of the network entity. The described aspects further include code for transmitting an acquisition signal during a subframe over an unlicensed band of the radio frequency spectrum to the UE.

In another aspect, the present apparatus relates to transmitting timing information in wireless communications. The described aspects include a mechanism for establishing, on a network entity, timing information for a discovery signal, wherein the timing information corresponds to the location of a current subframe of the network entity. The described aspects further include a mechanism for transmitting a discovery signal during a subframe over an unlicensed band of the radio frequency spectrum to the UE.

In a further aspect, the present apparatus relates to transmitting timing information in wireless communications. Aspects described include a memory configured to store data and one or more processors communicatively coupled to the memory, wherein the one or more processors and the memory are configured to establish, on a network entity, timing information for a discovery signal, wherein the timing information corresponds to the location of a current network subframe. object. The described aspects further include transmitting an acquisition signal during a subframe over an unlicensed band of the radio frequency spectrum to the UE.

Various aspects and features of the subject matter of the present invention are described in more detail below with reference to various examples, as shown in the accompanying drawings. Although the present disclosure of the subject matter of the present invention is given below with reference to various examples, it should be understood that the present disclosure of the subject matter of the present invention is not limited to this. Those skilled in the art having access to the teachings presented herein will recognize additional implementations, modifications and examples, as well as other uses, that are part of the disclosure of the subject matter of the present invention as described herein and with respect to which the disclosure the subject matter of the present invention may have significant benefits.

Brief description of drawings

A further understanding of the contents and advantages of the present invention can be realized with reference to the following drawings. In the accompanying drawings, similar components or functions may have the same reference label. In addition, different components of the same type may be distinguished by a subsequent reference mark by a second mark that distinguishes similar components. If a first reference mark is used in the description, the description is applicable to any of the like components having the same first reference mark regardless of the second reference mark.

In fig. 1 is a block diagram illustrating an example of several aspects of a communications system using co-located communications media.

In fig. 2 depicts the downlink frame structure used in LTE.

- 2 043472

In fig. 3 is a diagram illustrating an example of cyclic carrier sense adaptive transmission (CSAT) with time division multiplexing (TDM).

In fig. 4 is a schematic diagram illustrating an example of a communication network including an aspect of transmission and detection of synchronization information in wireless communication.

In fig. 5A and 5B are block diagrams illustrating an example of a method for detecting timing information in wireless communications.

In fig. 6 is a flowchart illustrating another example of a method for transmitting timing information in wireless communication.

In fig. 7 is a conceptual diagram illustrating an example of a discovery procedure between a UE and a network entity.

In fig. 8 is a simplified block diagram of several selected aspects of components that may be used in communication nodes.

In fig. Figure 9 is a simplified diagram of a wireless communication system.

In fig. 10 is a simplified diagram of a wireless communication system including small cells.

In fig. 11 is a simplified diagram illustrating wireless coverage areas.

In fig. 12 is a simplified block diagram of several selected aspects of communication components.

Detailed description

The present aspects generally relate to the transmission and detection of timing information in wireless communications. For example, prior to accessing, and exchanging information over, an unlicensed band of the radio spectrum, a base station or UE may perform a wait-before-answer (LBT) procedure to compete for access to the unlicensed band of the radio spectrum. The LBT procedure may include performing a channel unoccupied detection (CAD) procedure to determine whether an unlicensed radio frequency spectrum channel is available. The SCA procedure consists of two related functions, carrier sensing (CS) and energy detection (ED). Carrier sensing refers to the receiver's ability to detect and decode the incoming initial Wi-Fi signal. Energy Detection (ED) refers to the ability of a receiver to detect the non-Wi-Fi level of energy present on the current channel (frequency range) based on noise levels, environmental energy, sources of radio interference and unidentifiable Wi-Fi transmissions that may be damaged or more cannot be decoded. Unlike carrier sensing, which can determine the exact time interval during which the medium will be occupied by the current frame, energy detection must analyze the medium every time interval to determine whether energy is still present. After determining that the unlicensed RF spectrum channel is unavailable (eg, because another device is already using the unlicensed RF spectrum channel), the CCA procedure for the channel can be performed again at a later date.

Before a UE can communicate with a base station, the UE may need to discover or communicate with the base station (or cell). After a UE detects a base station or cell, the UE may need to periodically synchronize with the base station or cell in order to properly communicate and decode communications with the base station. In some examples, a base station may transmit a synchronization signal and the UE may receive and decode the synchronization signal to acquire and/or synchronize with the base station (or cell). Most transmissions on unlicensed communications equipment on unlicensed spectrum networks are made by transmitters after first complying with LBT protocols. However, certain transfers are performed without first checking to see if the channel is idle. CCA-exempt transmissions (CET) occur on both the downlink and uplink. In one aspect, the network may inhibit the CET and/or the detection signal transmitted to the CET may not be decodable due to interference. As a result, the timing information may not be known to the UE and, therefore, the UE may not be able to properly connect to the network.

Accordingly, in some aspects, the present methods and devices can provide an efficient solution over current solutions by transmitting and detecting timing information when conducting wireless communications over an unlicensed frequency spectrum. In cases where the network may disable the CET and/or the discovery signal transmitted to the CET cannot be decoded due to interference, the present methods and apparatus ensure that timing information can be transmitted as part of the discovery signal, instead of the CET. Essentially, the timing information allows the UE to determine the location of the current subframe in which the acquisition signal is present, which in turn causes the UE to determine the acquisition window, acquisition period, and radio frame boundaries.

Aspects of the disclosure of the subject matter of the present invention set forth in the following description and accompanying drawings are directed to the specific aspects disclosed. Alternative aspects may be developed without departing from the scope of the disclosure of the subject matter of the present invention. In addition, well-known aspects of the disclosure of the subject matter of the present invention may not be described in detail or may be omitted so as not to obscure more significant details. In addition, many aspects are described in terms of sequences of actions to be performed, for example, by elements of a computing device. It will be appreciated that the various actions described herein may be performed by specific circuits (eg, application specific integrated circuits (ASICs)), by software instructions executed by one or more processors, or by a combination of both. Further, the sequence of actions described herein may be considered to be fully embodied in any form of computer-readable storage medium storing thereon a corresponding set of machine instructions which, when executed, may cause the associated processor to perform the functionality described in this document. Thus, various aspects of the present invention may be embodied in a variety of different forms, all of which are considered to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspects may be described herein as, for example, a logical configuration for performing the described action.

In fig. 1 illustrates several nodes of an example communication system 100 (e.g., part of a communications network), where an access terminal may include a subframe component 420 (FIG. 4) and, where an access point may include a corresponding subframe component 460 (FIG. 4), wherein the respective components of the subframe operate to allow the access terminal to detect and/or synchronize with the access point when the access terminal is operating offline in an unlicensed range of the radio frequency spectrum. Details of the operation of the subframe component 420 and the subframe component 460 are described below with reference to FIG. 4-8. For purposes of illustration, various aspects of the subject matter of the present invention will be described in the context of one or more access terminals, access points, and network entities that communicate with each other. It should be noted, however, that the ideas presented herein may be applicable to other types of devices or other similar devices referred to by different terminology. For example, in various implementations, access points may refer to or be implemented as base stations, NodeB, eNodeB, Home NodeB, Home eNodeB, small cells, macro cells, femto cells, and so on, while access terminals may refer to or be implemented as user equipment (UE), mobile stations and so on.

Access points, which may correspond to a network entity 404 including a subframe component 420 (FIG. 4), in the system 100 provide access to one or more services (eg, a network connection) for one or more wireless terminals (eg, access terminal 102 or access terminal 104) that may be installed in or that may move throughout the coverage area of system 100. For example, at various times, access terminal 102 may be connected to access point 106 or to some other access point in system 100 ( not shown). Likewise, access terminal 104 may connect to access point 108 or some other access point.

One or more access points may communicate with one or more network entities (represented for convenience as network entities 110) including each other to facilitate connectivity to the wide area network. Two or more such network objects may be co-located and/or two or more such network objects may be distributed throughout the network.

A network entity may take various forms, such as, for example, one or more radios and/or core network entities. Thus, in various implementations, network entities 110 may represent functionality such as at least one of: network management (e.g., through an operating, administering, managing, and initializing entity), call management, session management, mobility management, gateway functions, interworking functions, or some other suitable network functionality. In some aspects, mobility management refers to: tracking the current location of access terminals using tracking zones, location zones, routing zones, or some other suitable method; managing paging for access terminals and providing access control for access terminals.

When access point 106 (or any other devices in system 100) uses the first RAT to communicate on a given resource, that communication may be subject to interference from nearby devices (e.g., access point 108 and/or access terminal 104) that use the second RAT to interaction on this resource. For example, communications using an LTE access point 106 in a particular unlicensed RF band may be subject to interference from Wi-Fi devices operating in that band. For convenience, LTE in the unlicensed RF spectrum may be referred to herein as Enhanced LTE/LTE in the unlicensed spectrum or simply LTE in context. In addition, a network or device that provides, adapts, or extends

Enhanced LTE/LTE in unlicensed spectrum may refer to a network or device that is configured to operate in a contented radio frequency band or spectrum.

In some systems, LTE in the unlicensed spectrum can be used in a standalone configuration, with all communications devices operating exclusively in the unlicensed portion of the wireless spectrum (for example, Standalone LTE). In other systems, LTE in the unlicensed spectrum may be used in a manner that is complementary to operation in the licensed spectrum by providing one or more unlicensed communications devices operating in the unlicensed portion of the wireless spectrum in combination with an assigned licensed communications device operating in the licensed portion of the wireless spectrum (eg Supplemental LTE Downlink (SDL)). In any case, communication equipment aggregation can be used to manage different components of communication equipment, with one communication device serving as the Primary Cell (PCell) for the corresponding UE (for example, an assigned licensed communication device in LTE SDL or a designated one of the unlicensed communication devices in Standalone LTE), and the remaining communication devices serve as corresponding Secondary Cells (SCells). Thus, the PCell can provide paired downlink and FDD uplink (licensed or unlicensed) and each SCell can provide additional downlink capacity as desired.

In general, LTE uses orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into several (K) orthogonal subcarriers, which are also commonly called tones, cells, and so on. Each subcarrier can be modulated with data. In general, modulation symbols are sent in a frequency domain with OFDM and a time domain with SC-FDM. The interval between adjacent subcarriers may be fixed and the total number of subcarriers (K) may depend on the system bandwidth. For example, K could be 128, 256, 512, 1024, or 2048 for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth can also be divided into subbands. For example, a subband may span 1.08 MHz and there may be 1, 2, 4, 8, or 16 subbands for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

In fig. 2 shows a downlink frame structure 200 used in LTE that can be used when sending messages from a subframe component 460 (FIG. 4) to a subframe component 420 (FIG. 4). The transmission timeline for the downlink may be divided into blocks of radio frames 202, 204, 206. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be divided into 10 subframes 208 with indices 0 to 9. Each subframe may include two slots, for example, slots 210. Each radio frame may thus include 20 slots with indices from 0 to 19. Each slot may include L symbol periods, for example, 7 symbol periods 212 for normal cyclic prefix (CP), as shown in FIG. 2, or 6 character periods for the extended cyclic prefix. Normal CP and extended CP may be referred to herein as different types of CP. The 2L symbol periods in each subframe may be assigned indices from 0 to 2L-1. Available time-frequency resources can be divided into resource blocks. Each resource block can span N subcarriers (eg, 12 subcarriers) in one slot.

In LTE, an access point (referred to as an eNB), which may correspond to a network entity 404 including a subframe component 420 (FIG. 4), may transmit a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) for each cell in the eNB. The primary and secondary synchronization signals may be sent in symbol periods 6 and 5, respectively, in each of subframes 0 and 5 of each normal cyclic prefix radio frame, as shown in FIG. 2. Synchronization signals can be used by access terminals (referred to as UEs) to detect and acquire a cell signal. The eNB may transmit a Physical Broadcast Channel (PBCH) during symbol periods 0-3 in slot 1 of subframe 0. The PBC may carry certain system information.

The eNB may transmit a specific Cell Pilot Signal (CRS) for each cell to the eNB. The CRS may be sent with symbols 0, 1, and 4 of each slot in the case of a normal cyclic prefix, and with symbols 0, 1, and 3 of each slot in the case of an extended cyclic prefix. CRS can be used by multiple UEs for coherent demodulation of physical channels, timing and frequency tracking, Radio Link Monitoring (RLM), Pilot Received Power (RSRP) and Pilot Received Quality (RSRQ) measurements and so on. The eNB can send a Physical Format Transfer Channel (PCFICH) ) only in part of the first symbol period of each subframe, although it is depicted in the entire first symbol period in FIG. 2. PCFICH may convey the number of symbol periods (M) used to control channels, where M may be 1, 2, or 3 and may vary from subframe to subframe. M can also be equal to 4 for a low system bandwidth, for example, with less than 10 resource blocks. In the example shown in FIG. 2, M=3. eNB may

- 5 043472 send a Physical HARQ Channel (PHICH) and a Physical Down Control Channel (PDCCH) in the first M symbol periods of each subframe (M=3 in FIG. 2). The PHICH may contain information to support Hybrid Automatic Retransmission (HARQ). The PDCCH may carry resource allocation information for multiple UEs and control information for downlink channels. Although this is not shown in the first symbol period in FIG. 2, it is understood that PDCCH and PHICH may also be included in the first symbol period. Likewise, the PHICH and PDCCH may also be in both the second and third symbol periods, although this is not shown in FIG. 2. The eNB may send a Physical Downstream Data Sharing Channel (PDSCH) in the remaining symbol periods of each subframe. The PDSCH may carry data for multiple UEs scheduled to transmit data on the downlink. The various signals and channels in LTE are described in 3GPP TS 36.211 entitled Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation, which is publicly available.

The eNB can send PSS, SSS and Strategic Missile Forces at the center of the 1.08 MHz system bandwidth used by the eNB. The eNB may send PCFICH and PHICH over the entire available system bandwidth in each symbol period in which these channels are sent. The eNB may send PDCCHs to groups of multiple UEs in certain portions of the system bandwidth. The eNB may send PDSCHs to specific UEs in certain portions of the system bandwidth. The eNB may broadcast PSS, SSS, PBCH, PCFICH, and PHICH to all UEs, may unicast PDCCH to specific UEs, and may also unicast PDSCH to specific UEs.

Multiple resource elements may be available in each symbol period. Each resource element can span one subcarrier in one symbol period and can be used to send one modulation symbol, which can be a real or complex value. Resource elements not used for the pilot in each symbol period may be organized into resource element groups (REGs). Each REG may include four resource elements in one symbol period. The PCFICH may occupy four REGs, which may be spaced approximately equally in frequency in symbol period 0. The PHICH may occupy three REGs, which may be spaced in frequency in one or more configurable symbol periods. For example, all three REGs for a PHICH may be part of symbol period 0 or may be distributed across symbol periods 0, 1, and 2. The PDCCH may occupy 9, 18, 32, or 64 REGs, which may be selected from the available REGs, in the first M periods characters. Only certain REG combinations may be allowed for the PDCCH.

The UE may know the specific REGs used for PHICH and PCFICH. The UE may search for different REG combinations for the PDCCH. The number of combinations to search is usually less than the number of allowed combinations for the PDCCH. The eNB may send PDCCH to the UE in any of the combinations that the UE will search for. A UE may be within the coverage area of multiple eNBs. One of the specified eNBs may be selected to serve the UE. The serving eNB may be selected based on various criteria such as received power, path loss, signal-to-interference ratio (SNR), and so on.

Returning to FIG. 1, the disclosure of the subject matter of the present invention relates in some aspects to techniques referred to herein as Carrier Sense Adaptive Transmission (CSAT), which can be used to facilitate coexistence between different technologies operating on a commonly used resource (eg, a particular unlicensed RF band or combined channel). Access point 106 includes co-located radios (eg, transceivers) 112 and 114. Radios 112 use a second RAT (eg, LTE) to communicate. Radio equipment 114 is able to receive signals using a first RAT (eg, Wi-Fi). In addition, interface 116 allows radio equipment 112 and 114 to communicate with each other.

This co-channel radio equipment is used to provide carrier sense multiple access (CSMA-like) operation, whereby the radio equipment 114 repeatedly (eg, periodically) takes measurements on the co-channel. Based on the measurement data, radio equipment 112 determines the extent of co-channel utilization by devices operating on the first RAT. Thus, radio equipment 112 is able to adapt its communication on the channel (using the second RAT) according to resource usage.

For example, if resource usage by Wi-Fi devices is heavy, the LTE radio equipment may adjust one or more transmission parameters that the LTE radio equipment uses for co-channel communications such that co-channel utilization by the LTE radio equipment is reduced. For example, LTE radio equipment may reduce its transmit duty cycle, transmit power, or frequency allocation. Conversely, if resource utilization by Wi-Fi devices is low, the LTE radio equipment may adjust one or more transmission parameters that the LTE radio equipment uses for co-channel communications, such that co-channel use by the LTE radio equipment

- 6 043472 increases. For example, LTE radio equipment may increase its transmission duty cycle, transmission power, or frequency allocation.

The disclosed circuitry may provide several advantages. For example, by adapting communications based on signals associated with the first RAT, the second RAT can be configured to respond only to co-channel use by devices that use the first RAT. Thus, interference from other devices (eg, non-Wi-Fi devices) or adjacent channel interference can be ignored if desired. As another example, the circuit allows a device that uses a given RAT to control the extent to which protection should be provided for co-channel communications by devices that use a different RAT. Moreover, such a scheme can be implemented in an LTE system without changing the LTE PHY or MAC. For example, these changes can be implemented by simply changing the LTE software.

In some aspects, the benefits discussed herein can be achieved by adding a Wi-Fi integrated circuit or similar functionality to an LTE access point. If necessary, a low-functionality Wi-Fi scheme can be used to reduce costs (for example, the Wi-Fi scheme simply provides low-level analysis).

As used herein, the term co-located (eg, radios, access points, transceivers, etc.) may include, in various aspects, one or more of the following, for example: components that are housed in a single package; components that are located in one processor; components that are located at a certain distance from each other or components that are connected through an interface (for example, an Ethernet switch), where the interface satisfies the latency requirements of any required intercomponent communication (for example, messaging).

Although aspects of the disclosure of the subject matter of the present invention are described with reference to adaptive carrier sense transmission, the disclosure of the subject matter of the present invention is not intended to be limited. The same and/or different aspects or methods described herein may, in some cases, be implemented using other mechanisms configured to allow coexistence between different technologies operating on a commonly used resource (eg, unlicensed spectrum).

In fig. 3 illustrates an example of a cyclic CSAT Time Division Multiplexing (TDM) mode for LTE in unlicensed spectrum transmitted by an access terminal, where the access terminal may include a subframe component 420 (FIG. 4) and, where the access point may include a corresponding subframe component 460 (FIG. 4), wherein the corresponding components of the subframe operate to allow the access terminal to detect and/or enable synchronization with the access point when the access terminal is operating offline in an unlicensed range of the radio frequency spectrum. Details of the operation of the subframe component 420 and the subframe component 460 are described below with reference to FIG. 4-8. During the TON time, transmission over the unlicensed RF band is permitted, which may be referred to as the CSAT ON period. During the TOFF time, transmission over the unlicensed RF band is disabled, which may be referred to as the CSAT OFF period, to allow the co-located Wi-Fi radio equipment to take measurements. Thus, round-robin TDM communication mode for LTE in unlicensed spectrum can be implemented to create adaptive TDM transmission patterns.

Fig. 4 is a diagram illustrating an example of a telecommunications network system 400 in accordance with an aspect of the subject matter disclosure of the present invention, including at least one UE 402 in a communications coverage area, at least one network entity 404 (e.g., a base state or Node B ). UE 402 may interact with network 406 through network entity 404. In one aspect, UE 402 may include one or more processors 456 and, in some cases, memory 458, which may operate in combination with subframe component 420 to detect timing information during implementation wireless communication.

Likewise, network entity 404 may include one or more processors 482 and, in some cases, memory 484, which may operate in combination with subframe component 460 to convey timing information in wireless communications. In other words, the corresponding components of the subframe operate to allow the UE or access terminal to detect and/or synchronize with the eNodeB or access point when the UE or access terminal is operating in standalone and/or communications equipment aggregation mode in the unlicensed frequency spectrum. Accordingly, the present aspects may allow the UE 402 to detect timing information in situations in which the network may inhibit the CET and/or the acquisition signal transmitted to the CET cannot be decoded due to interference.

In one aspect, network entity 404 may be a base station such as a NodeB in a UMTS network. UE 402 communicates with network 406 through network entity 404. In some aspects, multiple UEs, including UE 402, may be in communication coverage with one or more network entities, including network entity 404. In an example, UE 402 may transmit and/or or receive wireless communications 408/410 to and/or from network entity 404. In some aspects, UE 402 may interact with network entity 404 in licensed and/or unlicensed spectrum using communication channel 408 (eg, both uplink and and downlink) and downlink 410.

In one aspect, each network entity 404 may include a subframe component 460 that may be configured to transmit one or more discovery signals 432 including unlicensed radio spectrum timing information 434 to a UE, e.g., UE 402, which may be configured with the component subframe 420 to monitor one or more discovery signals 432. For example, in one aspect, discovery signal 432 may include, but is not limited to, a transmitted signal on a physical channel configured to provide information to the UE 402 for connection to network entity 404. In addition Moreover, for example, in one aspect, the synchronization information may include, but is not limited to, one or more bits indicating the location of the current subframe relative to the radio frame. In some cases, unlicensed spectrum may be considered to be any part of the radio frequency spectrum (eg, part of a shared channel in the radio frequency spectrum) whose use is not restricted by a spectrum licensing approach. In some cases, the network 406 may be allowed to operate with transmissions exempt (CET) from channel idle detection (CCA) and/or the detection signal 432 transmitted in the case of CET unable to be decoded due to interference. In one aspect, the CCA procedure determines whether an unlicensed radio frequency spectrum channel is available. In the previous examples, when CETs cannot be transmitted and/or received, timing information for network entity 404 may be difficult to obtain or otherwise determine. As such, the subframe component 460 of the network entity 404 may transmit a discovery signal 432 via the downlink 410 to the UE 402 without the need for a CET because the discovery signal 432 includes timing information 434 corresponding to the location of the current subframe of the network entity 404. For example, in one In an aspect, the subframe component 460 may transmit downlink control information (DCI) on a physical downlink control channel (PDCCH) and/or an extended PDCCH (ePDCCH) including timing information 434.

In one aspect, the subframe component 420 related to the UE 402 may include a monitoring component 430 that may be configured to monitor over an unlicensed radio spectrum band the discovery signal 432 from the network entity 404. In addition, the subframe component 420 related to the UE 402 may include a receive component 440 that may be configured to receive a discovery signal 432 during subframe 452 from network entity 404. Additionally, a subframe component 420 related to UE 402 may include a determine component 450 that may be configured to determine the location of the current subframe (corresponding to subframe 452) of the network entity 404 based on the discovery signal 432, wherein the discovery signal 432 includes timing information 434 corresponding to the location of the current subframe. As a result of determining the location of the current subframe, the UE 402 may determine timing information corresponding to a radio frame boundary of the network entity 404 and synchronize with the network entity 404. The subframe component 420 may be further configured to include a demodulation component 454, which may be configured to demodulate the ePDCCH based on the information about the timing included in the 432 detection signal.

In another aspect, the subframe component 460 of the network entity 404 may include an establishment component 470, which may be configured to establish timing information 434 for inclusion in the discovery signal 432. In some cases, the timing information 434 corresponds to the location of the current subframe of the network entity 404. In addition, subframe component 460 of network entity 404 may include a transmission component 480 that may be configured to transmit discovery signal 432 during subframe 452 over an unlicensed band of radio frequency spectrum to UE 402. As such, network entity 404 may transmit discovery signal 432 without the need for a CET .

Additionally, for example, telecommunications network system 400 may be an LTE network. The telecommunications network system 400 may include a number of enhanced NodeBs (eNodeBs) (eg, network entity 404) and multiple UEs 402 and other network entities. An eNodeB may be a station that communicates with multiple UEs 402 and may also be referred to as a base station, access point, and so on. NodeB is another example of a station that communicates with multiple UEs 402.

Each eNodeB (eg, network entity 404) may provide communications coverage for a specific geographic area. In 3GPP, the term cell may refer to the coverage area of an eNodeB and/or the eNodeB subsystem serving the coverage area, depending on the context in which the term is used.

The eNodeB (eg, network entity 404) may provide communications coverage for a small cell and/or other cell types. The term small cell (or small area cell) as used in

- 8 043472 herein, may refer to an access point or to a corresponding coverage area of an access point, where the access point in this case has a relatively low transmit power or a relatively small coverage area compared to, for example, the transmit power or coverage area of a macro access point network or macro cell. For example, a macro cell may cover a relatively large geographic area, such as, but not limited to, a radius of several kilometers. In contrast, a small cell may cover a relatively small geographic area, such as, but not limited to, a house, building, or floor of a building. As such, a small cell may include, but is not limited to, a device such as a base station (BS), access point, femto node, femtocell, pico node, micro node, NodeB, enhanced NodeB (eNB), home NodeB (HNB), or home advanced NodeB (HeNB). Thus, the term small cell, as used herein, refers to the relatively low transmit power and/or relatively small coverage area of a cell compared to a macro cell. The eNodeB for a macro cell may be referred to as a macro eNodeB. The eNodeB for a pico cell may be referred to as a pico eNodeB. The eNodeB for a femtocell may be referred to as a femto eNodeB or a home eNodeB.

In some aspects, UE 402 may also be referred to by those skilled in the art (also interchangeably herein) as a mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, portable telephone, terminal, user agent, mobile client, client, or any other terminology. The UE 402 may be a cellular telephone, a personal digital assistant (PDA), a wireless modem, a wireless communications device, a handheld device, a tablet computer, a laptop computer, a cordless telephone, a local radio station (WLL), a global positioning system (GPS) device, a multimedia device. , video device, digital audio player (e.g., MP3 player), camera, game console, wearable computing device (e.g., smart watch, smart glasses, health or exercise monitoring device, etc.), instrument, sensor, in-vehicle communication system , medical device, vending machine, Internet of Things device, or any other device with similar functionality. In addition, network entity 404 may be a macrocell, picocell, femtocell, relay, NodeB, mobile NodeB, UE (e.g., communicating in peer-to-peer or ad hoc mode with UE 402), or virtually any type of component that can interact with UE 402 to provide wireless network access on the UE 402.

As shown in FIG. 5, in operation, a UE such as UE 402 (FIG. 4) may perform an aspect of method 500A for detecting timing information while performing wireless communications. However, for the purpose of ease of explanation, the methods shown and described herein as sequences of actions should be understood and regarded as methods not limited by the order of actions, since some actions may, in accordance with one or more aspects, occur in a different order and /or in parallel with other actions that are shown and described in this document. For example, it should be understood that methods may alternatively be represented as sequences of interrelated states or events, such as in a state diagram. In addition, not all of the illustrated steps may be required to implement a method in accordance with one or more of the features described herein.

In one aspect, at block 510, method 500A includes monitoring the UE over an unlicensed band of radio frequency spectrum for a discovery signal from a network entity. For example, as described herein, the subframe component 420 may include a monitoring component 430 (FIG. 4) for monitoring at a UE (eg, UE 402) over an unlicensed radio frequency spectrum band the detection signal 432 from the network entity 404. In some cases discovery signal 432 includes an extended system information block (eSIB), wherein the eSIB includes SIB1, SIB2, and a MIB, which are parameters that allow the UE 402 to connect to network entity 404. In some examples, the discovery signal 432 includes timing information corresponding to a primary synchronization signal (PSS) and a secondary synchronization signal (SSS).

At block 520, method 500A includes receiving a discovery signal during a subframe from a network entity. For example, as described herein, subframe component 420 may include a receive component 440 (FIG. 4) for receiving an acquisition signal during the subframe from a network entity. In some cases, discovery signal 432 is received on a physical downlink control channel (PDCCH) and/or an extended PDCCH (ePDCCH) (eg, downlink channel 410 in FIG. 4) from network entity 404 during a CCA procedure to establish whether or not it is available. whether the channel is an unlicensed range of the radio frequency spectrum.

Additionally, at block 530, method 500A includes determining the location of a current subframe of a network entity based on a detection signal, wherein the detection signal includes

- 9 043472 timing information corresponding to the location of the current subframe. For example, as described herein, subframe component 420 may include a determination component 450 (FIG. 4) for determining the location of a current subframe of a network entity based on a discovery signal, wherein the discovery signal includes timing information corresponding to the location of the current subframe. In some aspects, method 500A may proceed to block 540 in FIG. 5V.

As shown in FIG. 5B, in one aspect, at block 540, method 500B includes demodulating a downlink control channel. For example, as described herein, subframe component 420 may include a demodulation component 454 (FIG. 4) for demodulating a downlink control channel. In some aspects, the downlink control channel may correspond to either a PDCCH or an ePDCCH. In some cases, subframe component 420 and/or demodulation component 454 may be configured to demodulate the ePDCCH based on timing information included in acquisition signal 432. Subframe component 420 may demodulate the ePDCCH without a cell-specific pilot signal (CRS).

In one aspect, at block 550, method 500B includes locating an eSIB in a subframe in response to demodulation of a downlink control channel. For example, as described herein, subframe component 420 may include a determination component 450 (FIG. 4) for determining the location of an eSIB in subframe 452 in response to ePDCCH demodulation.

In one aspect, at block 560, method 500B includes determining radio frame boundaries (RFBs) based on the location of the current subframe of a network entity. For example, as described herein, subframe component 420 may include a determiner component 450 (FIG. 4) to determine an RFB based on the location of the current subframe of network entity 404.

In one aspect, at block 570, method 500B includes determining a detection window and a detection period based on the location of the current subframe of the network entity. For example, as described herein, the subframe component 420 may include a determination component 450 (FIG. 4) for determining a detection window and a detection period based on the location of the current subframe of the network entity 404. In some cases, the size of the detection window and the value of the detection period are pre-configured. In other cases, the time indicator may be received by a component of the subframe 420 corresponding to timing information for the detection window. The detection signal 432 may be received as a non-periodic opportunistic signal during the detection window.

As shown in FIG. 6, during operation, a network entity such as network entity 404 (FIG. 4) may perform an aspect of method 600 for transmitting synchronization information in wireless communication. However, for the purpose of ease of explanation, the methods shown and described herein as sequences of actions should be understood and regarded as not limited by the order of actions, since some actions may, in accordance with one or more aspects, occur in a different order and/or in parallel with other activities shown and described herein. For example, it should be appreciated that the methods may alternatively be represented as a sequence of interrelated states or events, such as a state diagram. In addition, not all of the illustrated steps may be required to implement a method in accordance with one or more of the features described herein.

In one aspect, at block 610, method 600 includes establishing, in a network entity, timing information for signal detection, wherein the timing information corresponds to the location of a current subframe of the network entity. For example, as described herein, subframe component 460 may include establishment component 470 (FIG. 4) for establishing timing information on a network entity for a discovery signal, wherein the timing information corresponds to the location of the current subframe of the network entity. In some cases, discovery signal 432 includes an extended system information block (eSIB), wherein the eSIB includes at least one or more SIB1, SIB2, and a MIB, which are parameters used by the UE 402 to connect to network object 404.

In addition, subframe component 460 sets timing information 434 for detection signal 432 by determining the number of detection windows present during each detection period; and calculating the number of bits to include in the detection signal 432 based on determining the number of detection windows present during each detection period. In some cases, calculating the number of bits included in the detection signal 432 further includes calculating the number of bits based on the size of the detection window when one detection window is present during each detection period. In other cases, calculating the number of bits included in the detection signal 432 further includes calculating the number of bits based on the size of the detection period when more than one detection window is present during each detection period.

Additionally, at block 620, method 600 includes transmitting a detection signal during a subframe over an unlicensed band of radio frequency spectrum to user equipment.

- 10 043472 (UE). For example, as described herein, the subframe component 460 may include a transmission component 480 (FIG. 4) for transmitting an acquisition signal during the subframe over an unlicensed band of the radio frequency spectrum to a user equipment (UE). In some cases, a detection signal 432 is transmitted on the extended physical downlink control channel (ePDCCH) to the UE 402 during a channel unoccupied detection (CCA) procedure to determine whether an unlicensed radio frequency spectrum channel is available. As such, acquisition signal 432 includes timing information used for demodulating the ePDCCH and where the location of the eSIB in the subframe is determined in response to the demodulation of the ePDCCH. The timing information may include a primary timing signal (PSS) and a secondary timing signal (SSS). Moreover, in some cases, for example, the acquisition signal may be transmitted without a cell-specific pilot signal (CRS). The detection signal may also be transmitted by the subframe component 460 as a non-periodic opportunistic signal during the detection window.

In fig. 7 shows an example 700 of transmissions made by a network entity over an unlicensed portion of the radio frequency spectrum, in accordance with various aspects of the subject matter disclosure of the present invention. In some examples, the network entity making the transmissions may be an example of aspects of the network entity 404 described with reference to FIG. 4.

As an example, FIG. 7 illustrates transmissions over time performed by a network entity over time in three adjacent detection periods. The three adjacent detection periods include a first detection period 705, a second detection period 710, and a third detection period 715.

Transmissions performed by the network entity may include synchronous transmissions performed during downlink SETs (SET 720) of the network entity, synchronous transmissions performed during non-periodic subframe locations (eg, following successful SCA 725), and asynchronous transmissions performed during the discovery window 730.

A detection window 730 may be provided in each of a first detection period 705, a second detection period 710, and a third detection period 715; once every N detection periods (where N>1); or in one or more detection periods on a dynamic basis. The length or duration of the detection window 730 may be shorter or longer than shown. In some examples, detection window 730 may overlap in time with at least one non-periodic subframe location (eg, at least one subframe subsequent to CCA 725). In some examples, discovery window 730 may be associated with a different set of subcarrier frequencies in the unlicensed range of the radio frequency spectrum than the set of subcarrier frequencies included in CET 720, CCA 725, or the periodic fixed subframe subsequent to CCA 725.

In some aspects, a synchronization signal may be transmitted by a network entity during one or more CETs 720, during one or more periodic fixed subframe locations (e.g., the next one or more successful CETs 720), and/or during a discovery window 730. Transmission of the synchronization signal in during CET 720 or during a periodic fixed subframe may be considered synchronous transmission, while transmission of the synchronization signal during detection window 730 may be considered asynchronous transmission. In some examples, the transmitted synchronization signal may be used for discovery, cell synchronization, and/or other purposes. In some examples, the transmitted synchronization signal may include PSS and/or SSS.

In some aspects, a network entity may attempt to transmit an opportunistic discovery signal (eg, one or more CCAs 725) during discovery window 730. In certain cases, the network may be denied transmission of CET 720 and/or the discovery signal sent to CET 720 is unable to be decoded due to interference. As such, a network entity may transmit one or more CCAs 725, outside of the time period for transmitting CET 720, during discovery window 730, where one or more CCAs 725 may be discovery signals, such as discovery signal 432 in FIG. 4. CCA 725 may include timing information that the UE can use to determine the location of the current subframe in which the discovery signal was transmitted. Based on the timing information, the UE may be able to determine detection window boundaries 730 and/or detection period boundaries 705 or 710 or 715 and/or radio frame boundaries and essentially synchronize with the network entity and/or cell. Thus, receipt of CET 720 is no longer necessary for the UE to be able to properly synchronize with the network entity.

In fig. 8 illustrates several simple components (represented by respective blocks) that may be embedded in a device 802 (eg, an access terminal), which may correspond to a UE 402 (FIG. 4), which may correspond to a UE 4 02 including a subframe component 420 ( 4), both device 804 and device 806 (e.g., an access point and a network entity, respectively), where one or both of which may correspond to a network entity 404, including

- 11 043472 incorporating a subframe component 460 (FIG. 4) to support operation as described herein. It should be noted that these components can be implemented in different types of devices in different implementations (for example, in ASIC, in S°C, and so on). The components described may also be integrated into other devices in the communication system. For example, other devices in the system may include components similar to those described to provide similar functionality. In addition, the device may include one or more of the components described. For example, a device may include a plurality of transceiver components that allow the device to operate on multiple carriers and/or communicate using different technologies.

Device 802 and device 804 each include at least one wireless communications device (represented by communications devices 808 and 814 (and communications device 820 if device 804 is a repeater)) for communicating with other nodes through at least one provided technology with radio access. Each communications device 808 includes at least one transmitter (represented by transmitter 810) for transmitting and encoding signals (e.g., messages, display information, information, etc.) and at least one receiver (represented by receiver 812) to receive and decode signals (such as messages, display information, information, pilot signals, and so on). Likewise, each communication device 814 includes at least one transmitter (represented by transmitter 816) for transmitting signals (e.g., messages, information displays, information, pilot signals, and so on) and at least one receiver (represented by receiver 818) to receive signals (such as messages, display information, information, and so on). If device 804 is a repeater access point, each communication device 820 may include at least one transmitter (represented by transmitter 822) for transmitting signals (e.g., messages, display information, information, pilot signals, and so on) and, at least one receiver (represented by receiver 824) for receiving signals (eg, messages, display information, information, and so on).

The transmitter and receiver may include an integrated device (e.g., embodied as transmitter circuitry and receiver circuitry for a single communication device) in some implementations, may include a separate transmitter device and a separate receiver device in some implementations, or may be implemented in other ways in other implementations. In some aspects, the wireless communications device (eg, one of a plurality of wireless communications devices) of device 804 includes a network sniffing module.

Device 806 (and device 804 if it is not a relay access point) includes at least one communications device (represented by communications device 826 and, in some cases, 820) for communicating with other nodes. For example, communications device 826 may include a network interface that is configured to communicate with one or more network entities via wired or wireless transmission. In some aspects, communications device 826 may be implemented as a transceiver configured to support wired or wireless signaling. This communication system includes, for example, the transmission and reception of: messages, parameters or other types of information. Accordingly, in the example of FIG. 8, communications device 826 is shown to include a transmitter 828 and receiver 830. Likewise, if device 804 is not a repeater access point, communications device 820 may include a network interface that is configured to communicate with one or more network entities via a wired or wireless transmission. As communication device 826, communication device 820 is shown as including a transmitter 822 and a receiver 824.

Devices 802, 804, and 806 also include other components that may be used in conjunction with communication adaptation operations as described herein. Apparatus 802 includes one processor or more processors 456 to provide functionality related, for example, to communication with a communication adaptation support access point as described herein, and to provide other processing functionality. Apparatus 804 includes a processing system 834 to provide functionality related, for example, to communication adaptation as described herein, and to provide other processing functionality. Apparatus 806 includes one processor or more processors 482 to provide functionality related, for example, to communication adaptation as described herein, and to provide other processing functionality. Devices 802, 804, and 806 include memory devices 458, 840, and 484 (eg, each includes a memory device), respectively, for storing information (eg, information indicating reserved resources, thresholds, parameters, and so on). In addition, devices 802, 804, and 806 include a user interface for devices 844, 846, and 848, respectively, to provide display of information (e.g., audio and/or visual presentation of information) to the user and/or to receive user input (e.g., when user actions on a touch device such as a keypad, touch screen, microphone, etc.).

- 12 043472

For convenience, device 802 is shown in FIG. 8 as including components that may be used in the various examples described herein. In practice, the illustrated blocks may have different functionality in different aspects.

Components in FIG. 8 can be implemented in various ways. In some implementations, the components in FIG. 8 may be implemented in one or more circuits, such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or include at least one memory component for storing information or executable code used by the circuit to provide functionality. For example, some or all of the functionality represented by blocks 808, 832, 838 and 844 may be implemented by the processor and memory component(s) of device 802 (eg, through the execution of appropriate code and/or appropriate configuration of processor components). Likewise, some or all of the functionality represented by blocks 814, 820, 834, 840, and 846 may be implemented by the processor and memory component(s) of device 804 (eg, by executing appropriate code and/or by appropriate configuration of processor components). In addition, some or all of the functionality represented by blocks 826, 836, 842 and 848 may be implemented by the processor and memory component(s) of device 806 (eg, by executing appropriate code and/or by appropriate configuration of processor components).

Some of the access points mentioned in this document may include low power access points. In a typical network, low power access points (e.g., femtocells) are deployed to add conventional network access points (e.g., macro access points). For example, a low-power access point installed in a user's home or corporate environment (such as commercial buildings) can provide voice and high-speed data service to access terminals that support cellular radio communications (such as CDMA, WCDMA, UMTS, LTE, etc. ). In general, these low power access points provide more reliable coverage and higher throughput for access terminals in close proximity to the low power access points.

As used herein, the term low power access point refers to an access point having transmit power (e.g., one or more of: maximum transmit power, instantaneous transmit power, normal transmit power, average transmit power, or some other form of transmit power) , which is less than the transmit power (eg, as defined above) of any macro access point in the coverage area. In some implementations, each low power access point has a transmit power (eg, as defined above) that is less than the transmit power (eg, as defined above) of the macro access point by a relative power headroom (eg, 10 dBm or more). In some implementations, low power access points such as femtocells may have a maximum transmit power of 20 dBm or less. In some implementations, low power access points such as picocells may have a maximum transmit power of 24 dBm or less. Keep in mind, however, that data or other types of low-power access points may have higher or lower maximum transmit power in other implementations (e.g., up to 1 W in some cases, up to 10 W in some cases, and so on).

Typically, low-power access points connect to the Internet through a broadband connection (such as a digital subscriber line (DSL) router, cable modem, or some other type of modem) that communicates back to the mobile network operator. Thus, a low-power access point deployed in a user's home or business provides mobile network access to one or more devices via a broadband connection.

Various types of low power access points can be used in this system. For example, low power access points may be implemented as or referred to as femto cells, femto access points, small cells, femto nodes, home NodeBs (HNBs), home eNodeBs (HeNBs), access point base stations, pico cells, pico nodes, or micro cells.

For convenience, low power access points may be referred to simply as small cells in the discussion that follows. Thus, it should be understood that any discussion regarding small cells herein may be equally applicable to low power access points in general (eg, femtocells, microcells, picocells, etc.).

Small cells can be configured to support different types of access modes. For example, in open access mode, small cells can allow any access terminal to receive any type of service through the small cell. In a restricted (or closed) access mode, the small cell may allow only authorized access terminals to receive service through the small cell. For example, a small cell may allow only access terminals (eg, so-called home access terminals) belonging to a certain group of subscribers (eg, a closed subscriber group (CSG)) to receive service through the small cell. In hybrid access mode, third-party access terminals (eg, non-home access terminals, non-CSG access terminals) may provide limited access to the small cell. For example, a macro access terminal that does not belong to a small cell CSG may be allowed access to the small cell only if sufficient resources are available for all home access terminals that are currently served by the small cell.

Thus, operating small cells in one or more of these access modes can be used to provide indoor coverage and/or extended outdoor coverage. By providing access to users by adopting a desired access mode of operation, small cells can provide improved service within a coverage area and potentially expand service coverage for macro network users.

Thus, in some aspects, the ideas presented herein can be used in a network that includes a macro-scale coverage area (for example, a large-scale cellular network such as a third generation (3G) network, commonly referred to as a macrocellular network or WAN) and smaller coverage area (for example, a residential or building network environment, commonly called a LAN). When an access terminal (AT) roams in such a network, the access terminal may be served in certain locations by access points that provide macro coverage, while the access terminal may be served in other locations by access points that provide smaller coverage. In some aspects, smaller node coverage areas can be used to provide increased volume, in-building coverage, and various services (eg, a more reliable user experience).

As used herein, a node (e.g., an access point) that provides coverage over a relatively large area may be referred to as a macro access point, while a node that provides coverage over a relatively small area (e.g., a residence) , may be called a small cell. It should be understood that the ideas expressed herein may be applied to nodes associated with other types of coverage areas. For example, a pico access point may provide coverage (eg, coverage inside a commercial building) over an area that is smaller than the area of a macro and larger than the area of a femtocell. Different applications may use different terminology to refer to a macro access point, small cell, or other type of access point node. For example, a macro access point may be configured or referred to as an access node, base station, access point, eNodeB, macro cell, and so on. In some implementations, a node may be associated with (eg, named as, or subdivided into) one or more cells or sectors. A cell or sector associated with a macro access point, femto access point, or pico access point may be referred to as a macro cell, femto cell, or pico cell, respectively.

In fig. 9 illustrates a wireless communications system 900 configured to support a plurality of users, including one or more access terminals and access points having corresponding subframe components that operate to allow the access terminal to detect and/or synchronize with the access point when the access terminal is operating. offline in unlicensed frequency spectrum. System 900 provides communications for a plurality of cells 902 such as, for example, macro cells 9O2A-9O2G, with each cell served by a corresponding access point 904 (eg, access points 904A to 904G), which may correspond to a network entity 404 including a subframe component 460 ( Fig. 4). As shown in FIG. 9, access terminals 906 (eg, access terminals 906A - 906L), which may correspond to UE 402, including a subframe component 420 (FIG. 4), may be distributed to various locations throughout the system over time. Each access terminal 90 6 may communicate with one or more access points 904 on the forward link (FL) and/or reverse link (RL) at a given time, depending on whether the access terminal 906 is active and in soft switching, for example. The wireless communications system 900 can provide service over a large geographic area. For example, macro cells 902A-902G can cover several blocks in a neighborhood or several miles in a rural area.

In fig. 10 illustrates an example of a communications system 1000 where one or more small cells are deployed in a network environment. In particular, system 1000 includes a plurality of small cells 1010 (e.g., small cells 1010A and 1010B) that may correspond to a network entity 404 including a subframe component 460 (FIG. 4) installed in a relatively small-scale network environment (e.g. , in one or more places of residence of the user 1030). Each small cell 1010 may be connected to a wide area network 1040 (eg, the Internet) and a mobile carrier core network 1050 via a DSL router, cable modem, wireless link, or other communications device (not shown). As will be described below, each small cell 1010 may be configured to serve associated access terminals 1020 (e.g., access terminal 1020A) and, in some cases, other (e.g., hybrid or third-party) access terminals 1020 (e.g., access terminal 1020B), where each access terminal may correspond to a network UE 402 including a subframe component 420 (FIG. 4). In other words, access to small cells 1010 may be limited such that a given access terminal 1020 may be served by a set of assigned (eg, home) small cell(s) 1010, but may not be served by any unassigned small cells 1010 ( for example, neighbor small cell 1010). In fig. 11 illustrates an example coverage area map 1100 where multiple tracking areas 1102 (or routing areas or location areas) are defined, each of which includes multiple macro coverage areas 1104. Here, coverage areas associated with tracking areas 1102A, 1102B, and 1102C , are demarcated by thick lines and the macro coverage areas 1104 are represented by large hexagons. Tracking areas 1102 also include femto coverage areas 1106. In this example, each of the femto coverage areas 1106 (e.g., femto coverage areas 1106B and 1106C) are depicted within one or more macro coverage areas 1104 (e.g., macro coverage areas 1104A and 1104B). However, it should be understood that some or all of the femto coverage areas 1106 may not be within the macro coverage area 1104. In practice, a large number of femto coverage areas 1106 (eg, femto coverage areas 1106A and 1106D) may be defined within a given tracking area. 1102 or macro coverage area 1104. Additionally, one or more pico coverage areas (not shown) may be defined within a given tracking area 1102 or macro coverage area 1104.

Again with reference to FIG. 10, the owner of small cell 1010 may subscribe to a mobile service, such as, for example, a 3G mobile service offered through the mobile operator core network 1050. Additionally, access terminal 1020 may be capable of operating in both macro environments and network environments. small scale (for example, residential buildings). In other words, depending on the current location of the access terminal 1020, the access terminal 1020 may be served by a macro cell of the access point 1060 associated with the mobile operator core network 1050 or any of the set of small cells 1010 (for example, small cells 1010A and 1010B, which are located in within the corresponding place of residence of the user 1030). For example, when a subscriber is away from his home, he is served by a standard macro access point (eg, a 1060 access point) and, when the subscriber is at home, he is served by a small cell (eg, a 1010A small cell). Here, small cell 1010 may be backwards compatible with legacy access terminals 1020.

Small cell 1010 may be deployed on a single frequency or, alternatively, on multiple frequencies. Depending on the specific configuration, a single frequency or one or more of a plurality of frequencies may overlap with one or more frequencies used by a macro access point (eg, a 1060 access point).

In some aspects, access terminal 1020 may be configured to connect to a preferred small cell (eg, the home small cell of access terminal 1020) when such communication capability is available. For example, whenever access terminal 1020A is located within the residence of user 1030, access terminal 1020A may be required to communicate only with home small cell 1010A or 1010B.

In some aspects, if the access terminal 1020 operates within a macro cellular network 1050 but is not located in its most preferred network (e.g., as defined in a preferred roaming list), the access terminal 1020 may continue to search for a most preferred network (e.g., a preferred small-scale network). cell 1010) using a more advanced system reselection (BSR) procedure, which may include periodically scanning available systems to determine if better systems are currently available, and subsequently communicating with such preferred systems. The access terminal 1020 may limit the search to a specific band and channel. For example, one or more femto channels may be defined, whereby all small cells (or all limited small cells) operate in an area on the femto channel(s). The search for the most preferred system may be repeated periodically. After detecting the preferred small cell 1010, the access terminal 1020 selects the small cell 1010 and registers it for use when it is within its coverage area.

Access to a small cell may be limited in some aspects. For example, a given small cell may only provide certain services to certain access terminals. In a so-called limited (or closed) access deployment, a given access terminal can only be served by a mobile network with macro cells and a specific set of small cells (eg, small cells 1010 that are located within the respective residence of the user 1030). In some implementations, the access point may be limited to not provide, for at least one node (eg, an access terminal), at least one of signaling, data access, registration, paging, or service.

In some aspects, a limited small cell (which may also be referred to as a Closed Subscriber Group NodeB) is one that provides service to a limited designated set of access terminals. This set can be temporarily or permanently expanded as needed. In some aspects, a Closed Subscriber Group (CSG) can be defined as a set of access points (eg, small cells) that share a common access control list of access terminals.

- 15 043472

Thus, various relationships may exist between the small cell and a given access terminal. For example, from an access terminal's perspective, an open small cell may refer to a small cell with unrestricted access (eg, a small cell allows access to any access terminal). A restricted small cell may refer to a small cell that is restricted in some way (eg, restricted from access and/or registration). A home small cell may refer to a small cell on which an access terminal is authorized to access and operate (eg, persistent access is granted to a specific set of one or more access terminals). A hybrid (or guest) small cell may refer to a small cell in which different access terminals are provided with different levels of service (for example, some access terminals may be allowed partial and/or temporary access, while other access terminals may be allowed full access ). A third-party small cell may refer to a small cell on which the access terminal is not authorized to access or operate, except perhaps in emergency situations (eg, 911 emergency calls).

With respect to a restricted small cell, a home access terminal may refer to an access terminal that has rights to access a restricted small cell installed at the residence of the owner of said access terminal (usually the home access terminal has continuous access to the small cell). A guest access terminal may refer to an access terminal with temporary access to a small cell with restrictions (eg, limited based on a time-of-use deadline, bytes, number of connections, or some other criterion or criteria). A third-party access terminal may refer to an access terminal that does not have permission to access a limited small cell, except possibly in emergency situations such as calling 911 (for example, an access terminal that does not have credentials or permission to register on a small cell with restrictions).

For convenience of describing the subject matter of the present invention, various functionality is described herein in the context of a small cell. It should be understood, however, that a pico access point may provide the same or similar functionality over a larger coverage area. For example, a pico access point may be restricted, a home pico access point may be defined for a given access terminal, and so on.

The ideas set forth herein can be used in a multiple access wireless communication system that simultaneously supports communications for multiple wireless access terminals. Here, each terminal can communicate with one or more access points through forward and reverse link transmissions. The forward link (or downlink) refers to the communication link from the access points to the terminals and the reverse link (or uplink) refers to the communication link from the terminals to the access points. This communication link may be established through a single-input-single-output system, a multiple-input-multiple-output (MIMO) system, or some other type of system.

The MIMO system uses multiple (NT) transmit antennas and multiple (NR) receive antennas to transmit data. The MIMO channel formed by the NT transmit and NR receive antennas can be decomposed into independent NS channels, which are also called spatial channels, where NS<min{NT,NR}. Each of the independent NS channels corresponds to a measurement. A MIMO system can provide improved performance (eg, greater throughput and/or greater reliability) if the additional measurements created by multiple transmit and receive antennas are used.

A MIMO system can support Time Division Duplex (TDD) and Frequency Division Duplex (FDD). In a TDD system, the forward and reverse links are in the same frequency range so that the principle of reciprocity allows estimation of the forward link channel from the reverse link channel. This approach allows the access point to extract the transmit beamforming gain on the forward link when multiple antennas are available at the access point.

In fig. 12 illustrates in more detail the components of a wireless device 1210, which may correspond to a network entity 404 including a subframe component 460 (FIG. 4), and a wireless device 1250 (eg, a UE), which may correspond to a UE 402 including a subframe component 420 (FIG. 4), a typical communication system 1200, which may be adapted as described herein. At device 1210, traffic data for a number of data streams is provided from a data source 1212 to a transmission (TX) data processor 1214. Each data stream may then be transmitted through a corresponding transmit antenna.

TX data processor 1214 generates, encodes, and interleaves traffic data for each data stream based on the particular encoding scheme selected for that data stream to provide encoded data. The encoded data for each data stream may be multiplexed with the pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and can be used by the receiver system to estimate the channel response. Then the multiplexed pilot signal and

- 16 043472 the encoded data for each stream is modulated (that is, symbolically mapped) based on the particular modulation scheme (eg, BPSK, QSPK, M-PSK or M-QAM) selected for that data stream to provide modulation symbols. The data rate, encoding, and modulation for each data stream may be determined by instructions executed by processor 482. Data memory 484 may store program code, data, and other information used by processor 482 or other components of device 1210.

The modulation symbols for all data streams are then provided to the TX MIMO processor 1220, which may further process the modulation symbols (eg, for OFDM). The TX MIMO processor 1220 then provides the NT modulation symbol streams to the NT transceivers (XCVR) 1222A1222T. In some aspects, the TX MIMO processor 1220 applies beamforming weights to the symbols of the data streams and the antenna from which the symbol is transmitted.

Each transceiver 1222 receives and processes a corresponding symbol stream to provide one or more analog signals and additional conditions (eg, amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over a MIMO channel. The modulated NT signals from the 1222A-1222T transceivers are then transmitted from the NT 1224A-1224T antennas, respectively.

At apparatus 1250, transmitted modulated signals are received by NR antennas 1252A1252R and the received signal from each antenna 1252 is provided to a corresponding transceiver (XCVR) 1254A-1254R. Each transceiver 1254 processes (eg, filters, amplifies, and downconverts) a corresponding received signal, digitizes the processed signal to provide samples, and further processes the samples to provide a corresponding received symbol stream.

The receive (RX) data processor 1260 then receives and processes the received NR symbol stream from the NR transceivers 1254 based on the specific receiver processing technique to provide detected NT symbol streams. RX data processor 1260 then demodulates, deinterleavers, and decodes each detected symbol stream to reconstruct traffic data for the data stream. The RX processor's processing of data 1260 complements the processing that is performed by the TX MIMO processor 1220 and the TX data processor 1214 on device 1210.

Processor 456 periodically determines which precoding matrix to use (discussed below). Processor 456 generates a reverse link message including a matrix index portion and an estimated value portion. Data memory 458 may store program code, data, and other information used by processor 456 or other components of device 1250.

The reverse link message may include various types of information regarding the link and/or the received data stream. The reverse link message is then processed by TX data processor 1238, which also receives traffic data for a number of data streams from data source 1236, modulated by modulator 1280, conditioned by transceivers 1254A-1254R, and transmitted back to device 1210.

At device 1210, modulated signals from device 1250 are received by antennas 1224 driven by transceivers 1222, demodulated by demodulator (DEMOD) 1240, and processed by RX data processor 1242 to extract the reverse link message transmitted by device 1250. Processor 482 then determines which precoding matrix to use to determine the beamforming weights, then process the extracted message.

It should be noted that for each device 1210 and 1250, the functionality of two or more of the described components may be provided by a single component. It should also be noted that the various communication components illustrated in FIG. 12 and those described above may further be configured, if necessary, to implement communication adaptation as described herein. For example, processors 482/456 may interact with memory 484/458 and/or other components of corresponding devices 1210/1250 to implement communication adaptation, as described herein.

In some aspects, a device or any component of a device may be configured to (or configured to, or adapted to) provide functionality as described herein. This may be achieved, for example: by manufacturing (eg, manufacturing) the device or component so that it provides functionality; by programming a device or component to provide functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be manufactured to provide the required functionality. As another example, an integrated circuit may be manufactured to support desired functionality and then configured (eg, through programming) to provide the desired functionality. As another example, the processor circuitry may execute code to provide the required functionality.

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It should be understood that any reference to an element herein using a designation such as first, second, and so on generally does not limit the number or order of those elements. Rather, these designations may be used herein as a convenient way to distinguish between two or more elements or instances of an element. Thus, referring to the first and second elements does not mean that only two elements can be used there or that the first element must somehow precede the second element. In addition, unless otherwise indicated, the set of elements may include one or more elements. In addition, terminology of the form at least one of A, B or C, or one or more of A, B or C, or at least one of the group consisting of A, B and C, used in the description or claims , means A or B or C or any combination of these elements. For example, this terminology may include A, or B, or C, or A and B, or A and C, or A and B and C, or 2A, or 2B, or 2C, and so on.

Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, statements, information, signals, bits, symbols, and integrated circuits that may be referenced in the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields, or particles or any combination thereof.

In addition, those skilled in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic equipment, computer software, or combinations thereof. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are described above primarily in terms of their functionality. Whether such functionality is implemented in hardware or software, specific application and design constraints are imposed on the entire system. One skilled in the art may implement the described functionality in a variety of ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the subject matter of the present invention.

The methods, sequences, and/or algorithms described in connection with aspects disclosed herein may be implemented directly in hardware, in software modules executed by a processor, or combinations thereof. The software module may be located in RAM memory, flash memory, ROM memory, EEPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage media known in the art. An exemplary storage medium coupled to a processor such that the processor can read information from and write information to the storage medium. Alternatively, the storage medium may be integrated into the processor.

Accordingly, an aspect of the present invention may include a computer-readable medium including a method for scheduling a first set of subframes in a frame duration for traffic based at least in part on a first configuration for communications in an unlicensed frequency band; scheduling, based at least in part on the first configuration, a second set of subframes in the frame duration for detecting a primary user of the unlicensed frequency band (eg, detecting a radar installation); and adjusting the number of subframes in the first and second set of subframes based on the second communication configuration, wherein the second communication configuration is identified based on the type of primary user that is detected (eg, the type of radar installation). Accordingly, the disclosure of the subject matter of the present invention is not limited to the illustrated examples.

Although the foregoing disclosure of the subject matter of the present invention shows illustrative aspects, it should be noted that various changes and modifications may be made herein without departing from the scope of the disclosure of the subject matter of the present invention as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects of the subject matter disclosure described herein do not need to be performed in any particular order. In addition, although certain aspects may be described or stated in the singular, the plural is intended unless a limitation to the singular is expressly stated.

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Claims (24)

CLAIM 1. A method for detecting synchronization information in wireless communication, including the following operations: monitoring on a user equipment (UE) in an unlicensed range of the radio frequency spectrum a detection signal transmitted by a network entity on a downlink control channel, the detection signal comprising a timing signal and an extended system information block (eSIB) containing timing information corresponding to a non-periodic location of the current subframe a network object in at least one or more of a system information block 1 (SIB1), a system information block 2 (SIB2) or a service information block (MIB); receiving at the user equipment (UE) a discovery signal transmitted by the network entity on a downlink control channel, wherein the discovery signal is sent after performing a channel availability detection (CAD) procedure in an unlicensed range of the radio frequency spectrum; determining at the user equipment (UE) a non-periodic location of the current subframe received from the network entity based on the detection signal, wherein the detection signal includes timing information corresponding to the non-periodic location of the current subframe, and demodulating a downlink control channel based on the non-periodic location of the current subframe . 2. The method of claim 1, wherein the detection signal includes timing information corresponding to a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). 3. The method of claim 1, further comprising determining a radio frame boundary (RFB) based on the non-periodic location of the current subframe of the network entity. 4. The method of claim 1, further comprising determining a detection window and a detection period based on the non-periodic location of the current subframe of the network entity. 5. The method according to claim 4, wherein the first detection window value and the second detection period value are configured in advance. 6. The method of claim 4, wherein the detection signal is received as a non-periodic opportunistic signal during the detection window. 7. The method of claim 1, further comprising synchronizing with the network entity based on the non-periodic location of the current subframe corresponding to the subframe. 8. A device for detecting synchronization information in wireless communications, including a memory configured to store data, and one or more processors communicatively associated with the memory for monitoring on a user equipment (UE) in the unlicensed range of the radio frequency spectrum of the detection signal, transmitted by the network entity on a downlink control channel, wherein the detection signal comprises a synchronization signal and an extended system information block (eSIB) containing synchronization information corresponding to the non-periodic location of the current subframe of the network entity in at least one or more of the system information block 1 ( SIB1), system information block 2 (SIB2) or service information block (MIB); receiving at the user equipment (UE) a discovery signal transmitted by the network entity on a downlink control channel, wherein the discovery signal is sent after performing a channel availability detection (CAD) procedure in an unlicensed range of the radio frequency spectrum; determining at the user equipment (UE) a non-periodic location of the current subframe received from the network entity based on the discovery signal, wherein the discovery signal includes timing information corresponding to the non-periodic location of the current subframe; and demodulating the downlink channel based on the non-periodic location of the current frame. 9. The apparatus of claim 8, wherein the detection signal includes timing information of a corresponding primary synchronization signal (PSS) and a secondary synchronization signal (SSS). 10. The apparatus of claim 8, wherein the one or more processors and memory are configured to determine a radio frame boundary (RFB) based on the non-periodic location of the current subframe of the network entity. 11. The apparatus of claim 8, wherein the one or more processors and memory are configured to determine a detection window and a detection period based on the non-periodic location of the current subframe of the network entity. - 19 043472 12. The apparatus of claim 11, wherein the first detection window value and the second detection period value are pre-configured. 13. The apparatus of claim 11, wherein the detection signal is received as a non-periodic opportunistic signal during the detection window. 14. The apparatus of claim 8, wherein the one or more processors and memory are configured to synchronize with the network entity based on the non-periodic location of the current subframe corresponding to the subframe. 15. A machine-readable medium storing computer executable code for carrying out by one or more processors of the device according to claim 8, the operations of the method according to claims 1-7. 16. A method for detecting synchronization information in wireless communication, including the following steps: monitoring on user equipment (UE) in the unlicensed range of the radio frequency spectrum of the detection signal transmitted by the network object; receiving a detection signal on a user equipment (UE) transmitted by a network entity on a downlink control channel after performing a channel availability detection (CDA) procedure in an unlicensed radio frequency spectrum band; determining at the user equipment (UE) a non-periodic location of the current subframe received from the network entity based on the discovery signal, wherein the discovery signal includes timing information corresponding to the non-periodic location of the current subframe and an extended system information block (eSIB) containing timing information of at least at least one or more of a system information block 1 (SIB1), a system information block 2 (SIB2) or a service information block (MIB); and demodulating the downlink control channel based on the non-periodic location of the current subframe. 17. The method of claim 16, further including demodulating the downlink control channel and locating the eSIB in the subframe in response to demodulating the downlink control channel. 18. The method of claim 16, wherein the downlink control channel corresponds to either a physical downlink control channel (PDCCH) or an enhanced downlink control channel (ePDCCH). 19. The method of claim 16, further comprising synchronizing with the network entity based on the non-periodic location of the current subframe corresponding to the subframe of the network entity. 20. A device for detecting synchronization information during wireless communications, including a memory configured to store data, and one or more processors communicatively associated with the memory for monitoring on a user equipment (UE) in the unlicensed range of the radio frequency spectrum of the detection signal transmitted by the network object; the field of learning a detection signal on a user equipment (UE) from a network entity on a downlink control channel after a channel availability detection (CDA) procedure in an unlicensed range of the radio frequency spectrum; determining at the user equipment (UE) the non-periodic location of the current subframe of the network entity based on the discovery signal, wherein the discovery signal includes timing information corresponding to the non-periodic location of the current subframe, and an extended system information block (eSIB) containing timing information in at least one or more of a system information block 1 (SIB1), a system information block 2 (SIB2) or a service information block (MIB); and demodulating the downlink control channel based on the non-periodic location of the current subframe. 21. The apparatus of claim 20, wherein the one or more processors and memory are configured to demodulate the downlink control channel and locate the eSIB in a subframe in response to the demodulation of the downlink control channel. 22. The apparatus of claim 20, wherein the downlink control channel corresponds to either a physical downlink control channel (PDCCH) or an extended downlink control channel (ePDCCH). 23. The apparatus of claim 20, wherein the one or more processors and memory are configured to synchronize with the network entity based on the non-periodic location of the current subframe corresponding to the subframe. 24. A machine-readable medium storing computer executable code for carrying out by one or more processors of the device according to claim 20 the operations of the method according to claims 16-19. -