CN107623919B - Authorization assisted access communication with dynamic request-to-send and clear-to-send messaging - Google Patents

Abstract

The invention relates to dynamically using authorization to assist access communication for request-to-send and clear-to-send messages. The present disclosure relates to performing cellular communications in unlicensed spectrum by opportunistic introduction of the use of RTS and CTS messages in a manner that takes into account hidden nodes that may be present. A listen-before-talk procedure may be performed to determine whether the wireless medium is available. When the listen-before-talk procedure is complete, an amount of time according to a timing synchronization scheme of the cellular communication system until a next possible start time for communicating in the cellular communication system may be determined; the wireless medium may be occupied until a next possible start time for communicating in the cellular communication system in a manner selected based at least in part on an amount of time until the next possible start time for communicating in the cellular communication system. Cellular communication may be performed over a wireless medium at a next possible start time for communicating in a cellular communication system.

Description

Authorization assisted access communication with dynamic request-to-send and clear-to-send messaging

Technical Field

The present application relates to wireless communications, and more particularly to systems, devices, and methods for performing LAA communications using dynamic RTS/CTS.

Background

The use of wireless communication systems is growing rapidly. In recent years, wireless devices such as smartphones and tablets have become more sophisticated. In addition to supporting telephone calls, many mobile devices (i.e., user equipment devices or UEs) now provide access to the internet, email, text messaging, and navigation using the Global Positioning System (GPS), and are capable of operating sophisticated applications that take advantage of these functions. In addition, many different wireless communication technologies and standards exist. Some examples of wireless communication standards include GSM, UMTS (e.g., associated with WCDMA or TD-SCDMA air interfaces), LTE-advanced (LTE-A), HSPA, 3GPP2CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), IEEE 802.11(WLAN or Wi-Fi),IEEE 802.16(WiMAX)、BLUETOOTH^TMAnd so on.

The introduction of an ever increasing number of features and functions in wireless communication devices has also created a continuing need for improved wireless communications and improved wireless communication devices. It is particularly important to ensure the accuracy of signals transmitted and received by User Equipment (UE) devices, for example by wireless devices such as cellular telephones, base stations and relay stations used in wireless cellular communications. Furthermore, increasing the functionality of the UE device may place significant strain on the battery life of the UE device. Therefore, it is also very important to reduce power requirements in UE device design while allowing the UE device to maintain good transmit and receive capabilities to improve communications.

In addition to the above-mentioned communication standards, there are also extended standards that aim to improve transmission coverage in certain cellular networks. For example, LTE in unlicensed spectrum (LTE-U) allows cellular carriers to improve coverage in their cellular network by transmitting in the unlicensed 5GHz band (which is also used by many Wi-Fi devices). Licensed Assisted Access (LAA) describes a similar technique that aims to standardize LTE operation in the Wi-Fi band by using a contention protocol called Listen Before Talk (LBT), which facilitates coexistence with other Wi-Fi devices in the same band. However, coexistence of cellular and Wi-Fi communications in the same frequency band may still result in reduced data throughput and/or reduced streaming application (data streaming) performance when both Wi-Fi and LAA/LTE-U signals are present.

Disclosure of Invention

Embodiments of apparatuses, systems, and methods are provided herein that handle hidden nodes that may be present when performing cellular communications in unlicensed spectrum, such as according to LTE-U or LAA.

Techniques for reducing the likelihood of collisions occurring on a shared medium may improve the efficiency and effectiveness of communications on the shared medium when cellular communications are performed in a shared unlicensed spectrum. For example, wireless devices wishing to communicate over a shared wireless medium (e.g., including devices performing cellular communication) may collectively perform a Listen Before Talk (LBT) procedure to avoid transmitting when another transmission is detectable over the medium. Since such a procedure may take an indeterminate amount of time (e.g., depending on the duration of any transmission that occurs while performing the LBT procedure), the timing at which the shared medium becomes available to the device performing the LBT procedure may be indeterminate and unpredictable. For cellular communication systems utilizing timing synchronization schemes, this may result in an interval between successful completion of the LBT procedure and the next possible start time of cellular communication according to the timing synchronization scheme of the cellular communication system.

In accordance with the techniques described herein, wireless devices operating in such cellular communication systems utilizing unlicensed spectrum may opportunistically utilize such possible intervals to implement further collision avoidance techniques, such as exchanging Request To Send (RTS)/Clear To Send (CTS) handshakes, and/or sending CTS to local (CTS-to-self) messages, and/or sending Wi-Fi preambles or Wi-Fi NAVs (e.g., indicating the duration of a media reservation) to further reduce the likelihood of collisions. For example, since the interval between successful completion of the LBT procedure and the next possible start time for cellular communication over the wireless medium may have different lengths at different times, the wireless device may perform an RTS/CTS handshake, and/or opportunistically (e.g., according to the length of the interval) send a CTS-to-self or Wi-Fi preamble/NAV message. As one such possibility, a wireless device may perform an RTS/CTS handshake if the interval is long enough for such handshake, or the device may transmit a CTS-to-self message or Wi-Fi preamble/NAV if the interval is not long enough for RTS/CTS handshake, but long enough for such message, or may forego either technique if the interval is not long enough for one of the two techniques. A wireless device may transmit a reservation signal (e.g., cell-specific reference signal (CRS), noise, etc.) to maintain control of the wireless medium for any portion of time in the interval other than for the RTS/CTS handshake or CTS-to-self or Wi-Fi preamble/NAV message.

Such opportunistic application of RTS/CTS, CTS-to-self or Wi-Fi preamble/NAV techniques may improve the coexistence characteristics of cellular communication systems operating in unlicensed spectrum. For example, the LBT procedure may help reduce the likelihood of a collision between two nodes that may detect each other, while, at least in accordance with some embodiments, adding RTS/CTS handshaking and CTS-to-self messages may help reduce the likelihood of a hidden node making a collision more effective than if the LBT procedure were present alone. As another example, if wireless devices sharing a wireless medium may utilize duration information provided in RTS/CTS handshakes and/or CTS-to-self messages to determine to enter a low power mode for the duration of cellular communication (e.g., as part of their explicit channel assessment process), this may improve the operational efficiency of such devices, at least in accordance with some embodiments.

It is noted that the techniques described herein may be implemented in and/or used with a number of different types of devices, including but not limited to base stations, access points, cellular phones, portable media players, tablets, wearable devices, and various other computing devices.

This summary is intended to provide a brief overview of some of the subject matter described in this document. Thus, it should be understood that the features described above are merely examples and should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

Fig. 1 illustrates an exemplary (and simplified) wireless communication system according to some embodiments;

fig. 2 illustrates an example base station in communication with an example wireless User Equipment (UE) device, in accordance with some embodiments;

fig. 3 illustrates an exemplary block diagram of a UE according to some embodiments;

fig. 4 illustrates an exemplary block diagram of a base station according to some embodiments;

fig. 5 illustrates an exemplary wireless communication system according to some embodiments;

fig. 6 illustrates an exemplary communication system in which a plurality of different devices may communicate with each other over a particular frequency band, such as a 2.4GHz and/or 5GHz frequency band, using Wi-Fi, according to some embodiments;

fig. 7 illustrates exemplary aspects of LAA communication according to some embodiments;

fig. 8 is a flow diagram illustrating a possible exemplary LBT procedure in accordance with some embodiments;

fig. 9 illustrates an exemplary communication system with hidden nodes according to some embodiments;

fig. 10 is a flow diagram illustrating an example method for performing LAA communications using dynamic RTS/CTS, in accordance with some embodiments;

fig. 11-13 illustrate various possible LAA communication timelines according to which wireless devices may operate, according to some embodiments.

While the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present subject matter as defined by the appended claims.

Detailed Description

Acronyms

Various acronyms are used throughout this application. The definitions of the most prominent acronyms used, which may appear throughout this application, are as follows:

UE: user equipment

RF: radio frequency

BS: base station

GSM: global mobile communication system

UMTS: universal mobile communication system

LTE: long term evolution

LTE-U: unlicensed LTE

LAA: authorizing assisted access

TDD: time division duplex

FDD: frequency division duplexing

TX: transmission/transfer

RX: receiving/accepting

LAN: local area network

WLAN: wireless LAN

LBT: listen before talk

AP: access point

RAT: radio access technology

IEEE: institute of electrical and electronics engineers

Wi-Fi: wireless Local Area Network (WLAN) RAT based on IEEE 802.11 standard

Term(s) for

The following is a glossary of terms that may appear in this application:

memory medium-any of various types of non-transitory memory devices or storage devices. The term "storage medium" is intended to include mounting media such as CD-ROM, floppy disk, or tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory, such as flash memory, magnetic media, e.g., hard disks or optical storage devices; registers, or other similar types of memory elements, etc. The memory medium may also include other types of non-transitory memory or combinations thereof. Further, the memory medium may be located in a first computer system executing the program, or may be located in a different second computer system connected to the first computer system through a network such as the internet. In the latter example, the second computer system may provide the program instructions to the first computer system for execution. The term "memory medium" may include two or more memory media that may reside in different locations, such as different computer systems connected by a network. The memory medium may store program instructions (e.g., particularly computer programs) that may be executed by one or more processors.

Carrier medium-a memory medium as described above, and a physical transmission medium such as a bus, a network, and/or other physical transmission medium that conveys signals such as electrical, electromagnetic, or digital signals.

Computer system (or computer) -any of various types of computing or processing systems, including Personal Computer Systems (PCs), mainframe computer systems, workstations, network appliances, internet appliances, Personal Digital Assistants (PDAs), television systems, grid computing systems, or other devices or combinations of devices. In general, the term "computer system" may be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

User Equipment (UE) (or "UE device") -any of various types of computer system devices that are mobile or portable and perform wireless communications. Examples of UE devices include mobile phones or smart phones (e.g., iphones)^TMBased on Android^TMTelephone), tablet (e.g., iPad)^TM、Samsung Galaxy^TM) Portable gaming device (e.g., Nintendo DS)^TM、PlayStation Portable^TM、Gameboy Advance^TM、iPhone^TM) Wearable devices (e.g., smart watches, smart glasses), laptops, PDAs, portable internet devices, music players, data storage devices, or other handheld devices, etc. In general, the term "UE" or "UE device" may be broadly defined to encompass any electronic device, computing device, and/or telecommunications device (or combination of devices) that facilitates user transportation and is capable of wireless communication.

Wireless device-any of various types of computer system devices that perform wireless communications. The wireless device may be portable (or mobile) or may be fixed or fixed at some location. A UE is one example of a wireless device.

Communication device-any of various types of computer systems or devices that perform communication, where the communication may be wired or wireless. The communication device may be portable (or mobile) or may be fixed or fixed at some location. A wireless device is one example of a communication device. A UE is another example of a communication device.

Base Station (BS) -the term "base station" has its full scope of ordinary meaning and includes at least a wireless communication station installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

Processing element-refers to various elements or combinations of elements capable of performing functions in a device (e.g., user equipment device or cellular network device). The processing elements may include, for example: a processor and associated memory, portions or circuitry of an individual processor core, an entire processor core, a processor array, circuitry such as an ASIC (application specific integrated circuit), programmable hardware elements such as Field Programmable Gate Arrays (FPGAs), and any of a variety of combinations thereof.

Wi-Fi-the term "Wi-Fi" has its full scope of ordinary meaning and includes at least a wireless communication network or RAT, which is served by wireless lan (wlan) access points and provides connectivity to the internet through these access points. Most modern Wi-Fi networks (or WLAN networks) are based on the IEEE 802.11 standard and are marketed under the name "Wi-Fi". Wi-Fi (WLAN) networks are different from cellular networks.

Auto-refers to an action or operation performed by a computer system (e.g., software executed by a computer system) or device (e.g., a circuit, programmable hardware element, ASIC, etc.) without user input directly specifying or performing the action or operation. Thus, the term "automatically" is in contrast to an operation that is manually performed or specified by a user, wherein the user provides input to directly perform the operation. An automatic process may be initiated by input provided by a user, while subsequent "automatically" performed actions are not specified by the user, i.e., are not "manually" performed, where the user specifies each action to perform. For example, by selecting each field and providing input specifying information, a user filling out an electronic form (e.g., by typing information, selecting check boxes, making radio selections, etc.) is manually filling out the form, even though the computer system must update the form in response to the user action. The form may be automatically filled in by a computer system, wherein the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills in the form without any user entering answers specifying the fields. As indicated above, the user may invoke automatic filling of the form, but not participate in the actual filling of the form (e.g., the user does not manually specify answers for the fields but rather they are automatically completed). This specification provides various examples of operations that are automatically performed in response to actions that have been taken by a user.

Configured-various components may be described as "configured to" perform one or more tasks. In such contexts, "configured to" is a broad expression generally meaning "having" a structure that performs one or more tasks during operation. Thus, a component may be configured to perform a task even when the component is not currently performing the task (e.g., a set of electrical conductors may be configured to electrically connect a module to another module even when the two modules are not connected). In some contexts, "configured to" may be a broad expression generally representing a structure "having" circuitry to perform one or more tasks during operation. As such, a component may be configured to perform a task even when the component is not currently on. In general, the circuitry forming the structure corresponding to "configured to" may comprise hardware circuitry.

For ease of description, various components may be described as performing one or more tasks. Such description should be construed to include the phrase "configured to". Expressing a component configured to perform one or more tasks is expressly intended to exclude such component from reference to the interpretation of 35u.s.c. § 112, sixth paragraph.

FIGS. 1 and 2-exemplary communication System

Fig. 1 illustrates an exemplary (and simplified) wireless communication system in which various aspects of the disclosure may be implemented, according to some embodiments. It is noted that the system of fig. 1 is merely one example of one possible system and that embodiments may be implemented in any of a variety of systems, as desired.

As shown, such an exemplary wireless communication system includes a base station 102 that communicates with one or more (e.g., any number) of user devices 106A, 106B, etc. to 106N over a transmission medium. Each user equipment may be referred to herein as a "user equipment" (UE) or UE device. Thus, the user equipment 106 is referred to as a UE or UE device.

The base station 102 may be a Base Transceiver Station (BTS) or a cell site and may include hardware and/or software that enables wireless communication with the UEs 106A-106N. If the base station 102 is applied in the context of LTE, it may be referred to as an "eNodeB". The base station 102 may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunications network such as a Public Switched Telephone Network (PSTN) and/or the internet, among various possibilities). Accordingly, the base station 102 may facilitate communication between user equipment and/or between user equipment and the network 100. The communication area (or coverage area) of a base station may be referred to as a "cell". Also as used herein, with respect to a UE, a base station may be considered to represent a network, sometimes taking into account uplink and downlink communications for the UE. Thus, a UE communicating with one or more base stations in a network may also be interpreted as a UE communicating with the network.

Base station 102 and user equipment may be configured to communicate over a transmission medium using any of a variety of Radio Access Technologies (RATs), also referred to as wireless communication technologies or telecommunication standards, such as GSM, UMTS (WCDMA), LTE advanced (LTE-a), NR, LAA/LTE-U, 3GPP2CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, WiMAX, and so forth.

Base station 102 and other similar base stations operating according to the same or different cellular communication standards may thus be provided as one or more cellular networks that may provide continuous or near-continuous overlapping service to UEs 106 and similar devices over a geographic area via one or more cellular communication standards.

It is noted that the UE 106 is capable of communicating using multiple wireless communication standards. For example, the UE 106 may be configured to use a 3GPP cellular communication standard (such as LTE) and/or a 3GPP2 cellular communication standard(s)Such as a cellular communication standard of the CDMA2000 series of cellular communication standards). In some embodiments, the UE 106 may be configured to perform LAA/LTE-U communication in a manner that takes into account the possibility of hidden nodes, at least in accordance with various methods as described herein. The UE 106 may also or alternatively be configured to use WLAN, BLUETOOTH^TMOne or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one and/or more mobile television broadcast standards (e.g., ATSC-M/H or DVB-H), and so on. Other combinations of wireless communication standards, including more than two wireless communication standards, are also possible.

Fig. 2 illustrates an example user equipment 106 (e.g., one of devices 106A-106N) in communication with a base station 102, in accordance with some embodiments. The UE 106 may be a device with wireless network connectivity, such as a mobile phone, a handheld device, a wearable device, a computer, or a tablet, or virtually any type of wireless device. The UE 106 may include a processor configured to execute program instructions stored in a memory. The UE 106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively or additionally, the UE 106 may include programmable hardware elements such as an FPGA (field programmable gate array) configured to perform any of the method embodiments described herein or any portion of any of the method embodiments described herein. The UE 106 may be configured to communicate using any of a number of wireless communication protocols. For example, the UE 106 may be configured to communicate using two or more of CDMA2000, LTE-A, WLAN, or GNSS. Other combinations of wireless communication standards are possible.

The UE 106 may include one or more antennas for communicating in accordance with one or more RAT standards using one or more wireless communication protocols. In some embodiments, the UE 106 may share one or more portions of a receive chain and/or a transmit chain among multiple wireless communication standards; the shared radio may include a single antenna, or may include multiple antennas for performing wireless communication (e.g., for MIMO). In general, the radio components may include any combination of baseband processors, analog RF signal processing circuits (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuits (e.g., for digital modulation and other digital processing). Similarly, the radio may implement one or more receive chains and transmit chains using the aforementioned hardware.

In some embodiments, the UE 106 may include separate transmit and/or receive chains (e.g., including separate antennas and other radios) for each wireless communication protocol configured to communicate therewith. As another possibility, the UE 106 may include one or more radios shared between multiple wireless communication protocols, as well as one or more radios used exclusively by a single wireless communication protocol. For example, the UE 106 may include shared radio components for communicating using any of LTE or CDMA 20001 xRTT (or LTE or GSM), as well as for communicating using Wi-Fi and BLUETOOTH^TMEach of which communicates. Other configurations are also possible.

FIG. 3-exemplary UE block diagram

Fig. 3 illustrates a block diagram of an exemplary UE 106, in accordance with some embodiments. As shown, the UE 106 may include a system on a chip (SOC)300, which may include portions for various purposes. For example, as shown, SOC 300 may include one or more processors 302 that may execute program instructions of UE 106 and display circuitry 304 that may perform graphics processing and provide display signals to display 360. The one or more processors 302 may also be coupled to a Memory Management Unit (MMU)340, which may be configured to receive addresses from the one or more processors 302 and translate those addresses to locations in memory (e.g., memory 306, Read Only Memory (ROM)350, NAND flash memory 310), and/or other circuits or devices, such as display circuitry 304, radio 330, connector I/F320, and/or display 360. MMU 340 may be configured to perform memory protections and page table translations or settings. In some embodiments, MMU 340 may be included as part of one or more processors 302.

As shown, the SOC 300 may be coupled to various other circuits of the UE 106. For example, the UE 106 may include various types of memory (e.g., including NAND flash memory 310), a connector interface 320 (e.g., for coupling to a computer system), a display 360, and wireless communication circuitry 330 (e.g., for LTE, LTE-a, NR, CDMA2000, BLUETOOTH)^TMWiFi, GPS, etc.). UE device 106 may include at least one antenna (e.g., 335a), and possibly multiple antennas (e.g., as shown by antennas 335a and 335 b) for performing wireless communications with base stations and/or other devices. Antennas 335a and 335b are shown by way of example, and UE device 106 may include fewer or more antennas. Collectively, one or more antennas are referred to as antennas 335. For example, the UE device 106 may perform wireless communications with the radio circuitry 330 using the antenna 335. As described above, in some embodiments, a UE may be configured to wirelessly communicate using multiple wireless communication standards.

As described further herein below, the UE 106 (and/or the base station 102) may include hardware components and software components for implementing the following methods: at least the UE 106 is caused to perform LAA/LTE-U communication in a manner that takes into account hidden nodes that may be present. The one or more processors 302 of the UE device 106 may be configured to implement a portion or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, the one or more processors 302 may be configured as programmable hardware elements, such as an FPGA (field programmable gate array) or as an ASIC (application specific integrated circuit). Further, as shown in fig. 3, the processor 302 may be coupled to and/or may interoperate with other components to perform LAA/LTE-U communications by the UE 106 that account for hidden nodes that may be present according to various embodiments disclosed herein. The one or more processors 302 may also implement various other applications and/or end-user applications running on the UE 106.

In some embodiments, radio 330 may includeIncluding separate controllers dedicated to controlling communications for the various respective RAT standards. For example, as shown in FIG. 3, radio 330 may include a Wi-Fi controller 350, a cellular controller (e.g., LTE controller) 352, and a BLUETOOTH^TMThe controller 354, and in at least some embodiments, one or more, or all of the controllers, can be implemented as respective integrated circuits (referred to simply as ICs or chips) that communicate with each other and with the SOC 300, and more specifically with the one or more processors 302. For example, Wi-Fi controller 350 can communicate with cellular controller 352 over a cell-ISM link or a WCI interface, and/or BLUETOOTH^TMThe controller 354 may communicate with the cellular controller 352 via a cell-ISM link or the like. Although three separate controllers are shown within the radio 330, other embodiments having fewer or more similar controllers for various different RATs may be implemented in the UE device 106.

FIG. 4-exemplary base station block diagram

Fig. 4 illustrates a block diagram of an example base station 102, in accordance with some embodiments. It is noted that the base station of fig. 4 is only one example of possible base stations. As shown, base station 102 may include one or more processors 404 that may execute program instructions for base station 102. The one or more processors 404 may also be coupled to a Memory Management Unit (MMU)440, or other circuit or device, which may be configured to receive addresses from the one or more processors 404 and translate those addresses to locations in memory (e.g., memory 460 and Read Only Memory (ROM) 450).

The base station 102 may include at least one network port 470. As described above in fig. 1 and 2, the network port 470 may be configured to couple to a telephone network and provide a plurality of devices, such as the UE device 106, with access to the telephone network. The network port 470 (or additional network port) may also or alternatively be configured to couple to a cellular network, such as a core network of a cellular service provider. The core network may provide mobile-related services and/or other services to multiple devices, such as UE device 106. In some cases, the network port 470 may be coupled to a telephone network via a core network, and/or the core network may provide the telephone network (e.g., in other UE devices served by a cellular service provider).

The base station 102 may include at least one antenna 434 and possibly multiple antennas. The one or more antennas 434 may be configured to function as wireless transceivers and may be further configured to communicate with the UE device 106 via the radio 430. One or more antennas 434 communicate with radio 430 via communication link 432. Communication chain 432 may be a receive chain, a transmit chain, or both. Radio 430 may be designed to communicate via various wireless telecommunication standards including, but not limited to, LTE-a, NR, WCDMA, CDMA2000, and the like. The processor 404 of the base station 102 may be configured to implement a portion or all of the methods described herein, such as by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium) to communicate the base station 102 with the UE device using LAA/LTE-U communication in a manner that accounts for the potential presence of hidden nodes. Alternatively, the processor 404 may be configured as a programmable hardware element, such as an FPGA (field programmable gate array), or as an ASIC (application specific integrated circuit), or a combination thereof. In the case of certain RATs (e.g., Wi-Fi), the base station 102 may be designed as an Access Point (AP), in which case the network port 470 may be implemented to provide access to a wide area network and/or one or more local area networks, e.g., it may include at least one ethernet port, and the radio 430 may be designed to communicate in accordance with the Wi-Fi standard. The base station 102 can operate in accordance with various methods disclosed herein to communicate with mobile devices using LAA/LTE-U in a manner that accounts for hidden nodes that may be present.

FIG. 5-an exemplary communication system

Fig. 5 illustrates an example wireless communication system 500 in which aspects of the disclosure may be implemented, according to some embodiments. System 500 is a system implementing an LTE access network and a Wi-Fi wireless access network. The system 500 may include the UE 106 and an LTE network 504 and a Wi-Fi network 506.

LTE access network 504 represents some embodiments of first RAT access and Wi-Fi access network 506 represents some embodiments of second RAT access. The LTE access network 504 may interact with a broader cellular network (e.g., an LTE network), and the Wi-Fi access network 506 may interact with the internet 514. More specifically, the LTE access network 504 may interact with a serving Base Station (BS)508, which in turn may provide access to a wider cellular network 516. The Wi-Fi access network 506 may interact with an Access Point (AP), which may in turn provide access to the internet 514. Thus, the UE 106 may access the internet 514 via the AP 510 and the cellular network 516 via the LTE access network 504. In some embodiments, although not shown, the UE 106 may also access the internet 514 via the LTE access network 504. More specifically, the LTE access network 504 may interact with a serving gateway, which in turn may interact with a Packet Data Network (PDN) gateway. The PDN gateway may then interact with the internet 514. Thus, the UE 106 may access the internet 514 via one or both of the LTE access network 504 and the Wi-Fi access network 506.

FIG. 6-exemplary communication System with multiple Wi-Fi devices

Fig. 6 illustrates an example communication system 650 in which multiple different devices can communicate with each other over a particular frequency band, such as 2.4GHz and/or 5GHz frequency bands, using a Wi-Fi RAT. As shown in fig. 6, devices supporting 5GHz Wi-Fi (e.g., IEEE 802.11ac/n) have become fairly common, such devices operating in peer-to-peer mode and/or infrastructure/station mode. Data communications over a particular frequency band (e.g., over the 5GHz band) may include voice, video, real-time, and best effort traffic types. The devices shown include a camera (611), a tablet (613), a speaker (615), a portable computer (605,617), an access port/router (603), a game controller (619), a mobile device such as a smart phone (607), and a smart monitor (621) or monitor having a wireless access interface (621) with a media processing device 623. As shown in fig. 6, many of these devices may communicate with each other (and/or with the internet 601, e.g., via access point 603) over the 5GHz band using Wi-Fi communication technology. In some cases, Wi-Fi communications by a device may be affected by LAA/LTE-U communications that also occur on the 5GHz band.

FIG. 7-LAA structural overview

In LTE, Carrier Aggregation (CA) refers to two or more Component Carriers (CCs) being aggregated in order to support a wider transmission bandwidth, e.g., a bandwidth of up to 100 MHz. Depending on the capability of the UE, the UE may receive or transmit simultaneously on one or more CCs. When configured as CA, the UE may maintain an RRC connection with the network. A serving cell that manages RRC connection of the UE is referred to as a primary cell (PCell), and a secondary cell (SCell) may form a set of serving cells together with the PCell. In CA, UEs may be scheduled simultaneously via PDCCHs on multiple serving cells. Cross-carrier scheduling using a Carrier Indicator Field (CIF) allows a PDCCH of a serving cell to schedule resources on another serving cell. That is, a UE receiving a downlink assignment on one CC may receive associated data on another CC.

LAA is a subcategory of LTE in-band carrier aggregation where one of the secondary carriers operates in the 5GHz unlicensed band over which communications according to another RAT (such as Wi-Fi) may also occur. The resources in the LAA carrier may be scheduled in the same way as the resources in the legacy CA. That is, the LAA carriers may be scheduled using the same carrier scheduling arrangement and/or cross-layer scheduling arrangement (e.g., using PDCCH or ePDCCH). At least according to some embodiments, the LAA Scell may operate in a frame structure 3 consisting of 20 slots and may be accessed after a successful Listen Before Talk (LBT) procedure. Fig. 7 shows an example of typical LAA control and data scheduling, providing an example of same carrier scheduling (710) (e.g., in which case the control information of the SCell may be provided using PDCCH resources of the SCell) and cross-carrier scheduling (720) (e.g., in which case the control information of the SCell may be provided using PDCCH resources of the PCell) assuming that the LBT procedure was successfully completed in the previous subframe. Note that if the start position of the RRC subframe indicates "s 07" and no DCI is received in slot 1, the UE may read the PDCCH/ePDCCH of slot 2 to check for downlink data availability, according to some embodiments.

It is noted that the LAA may be used for downlink communications and/or uplink communications (e.g., depending on the applicable standard release and/or implementation choice). For example, according to some embodiments, LAA release 13 may include standard specification details for downlink transmissions using scells, while LAA release 14 may include standard specification details for downlink and uplink transmissions using scells.

FIG. 8-LBT procedure

Fig. 8 shows an exemplary flow chart of an LBT procedure. It is noted that the process shown in fig. 8 represents one possible LBT process, and that any number of variations or alternatives to the process of fig. 8 are possible. In general, LBT procedures may be used to help avoid causing collisions on a shared wireless medium by: the wireless medium is monitored to determine if any transmissions are already in progress and if it is determined that a transmission is in progress, no transmission is made.

As shown, initially, at 802, a base station (e.g., shown as an eNB in fig. 8) may determine to initiate a downlink transmission using a shared wireless medium, such as a 5GHz unlicensed frequency band.

At 804, the eNB may monitor the availability of the wireless medium to continuously determine whether the channel is idle for a predetermined period of time. The length of time may depend on the type of communication to be transmitted (e.g., priority). For example, different lengths of time may be used for some or all of voice, video, best effort, and background communications, according to some embodiments. In the exemplary scenario illustrated in fig. 8, the time period may comprise a base length of 16 microseconds plus a variable length, the latter being 9 microseconds multiplied by a coefficient selected based on the type of communication. For example, according to some embodiments, the time period may be 43 μ s (e.g., 16+9 x 3) for best effort communications. Other values (and algorithms for determining values) may also or alternatively be used for predetermined time periods, as desired.

If the wireless medium is not continuously available for the predetermined period of time (e.g., if the wireless medium is busy or becomes busy before the predetermined period of time expires), the eNB may continue to monitor the wireless medium until the wireless medium is continuously idle for the predetermined period of time, at which point the method may proceed to step 806.

At 806, the eNB may generate a random counter N having a value within a specified Contention Window (CW) range, e.g., between 0 and a predetermined maximum possible value CW.

At 808, it may be determined whether the counter N is equal to 0. If so, the method may proceed to step 810, where the eNB may continue to transmit for its transmission opportunity. If the counter N is not equal to 0, the method may proceed to step 812, where the counter N may be decreased by 1.

At 814, it may be determined whether the wireless medium remains idle for 1 Wi-Fi slot (e.g., 9 μ β). If not, the method may proceed to step 816, where the eNB may again monitor the availability of the wireless medium (e.g., in a similar manner as in step 804) to determine whether the channel is continuously idle for a predetermined period of time. The eNB may repeat this step as needed until the channel is continuously idle for a predetermined period of time.

If the result of step 814 or step 816 is "yes," the method may return to step 808, where it may be determined whether the counter N is currently equal to 0. As previously described, once the counter N is equal to 0, the method may proceed to step 810, where the eNB may continue to transmit for its transmission opportunity. Otherwise, the method may repeat the countdown of counter N when the wireless medium is idle according to the illustrated procedure.

FIG. 9-communication system with hidden nodes

Fig. 9 shows a possible exemplary wireless communication system 900 in which hidden nodes are present. As shown, several UE devices 106A, 106B, 106C, 106D, 106E may be in proximity to each other. However, not all UE devices 106 may be within communication range of each other. For example, as shown, UE device 106A may have a communication range 902 that extends to UE 106B, UE 106C and UE 106E, but may not be able to transmit to UE 106D and/or receive from UE 106D. Similarly, UE device 106B may have a communication range 904 that extends to UE 106A, UE 106C and UE 106D, but may not be able to transmit to UE 106E and/or receive from UE 106E.

In this case, for example, where UE 106D is a hidden node with respect to UE 106A (and vice versa), a collision may occur in the wireless medium if, for example, both UE 106A and UE 106D are to transmit data to UE 106B. This, in turn, may cause interference to occur at the UE 106B such that the UE 106B may not be able to successfully decode any of the transmissions, wasting time, power, and wireless medium resources in efficiency.

Such a case and its variants may be an illustration commonly referred to as a "hidden node problem". The hidden node problem can occur both when the wireless medium is used uniformly (e.g., by devices using the same communication technology) and when the wireless medium is used in a mixture (e.g., by devices using multiple different communication technologies). For example, in some embodiments, wireless communication system 900 may represent the following system: wherein the wireless medium used comprises a mixed unlicensed spectrum. In this case, the UE devices 106A-E may include any combination of LAA/LTE devices, Wi-Fi sites, APs, and/or other devices using shared spectrum. Thus, in this scenario, a hidden node problem may arise between any combination of LAA/LTE-U and Wi-Fi stations and APs.

One approach to potentially reducing the number and/or severity of such collisions due to undetected hidden nodes may include the use of request-to-send (RTS) and clear-to-send (CTS) messages. For example, if UE 106A were to send an RTS message to UE 106B, and UE 106B responded with a CTS message that may be detected by UE 106D (and other potential nodes that may not be able to detect the RTS message transmitted by UE 106A), UE 106D may refrain from transmitting while UE 106A is transmitting to UE 106B, thereby preventing potential collisions and resulting interference. For example, LAA communication techniques that dynamically and opportunistically use RTS/CTS messages, such as those further described herein with respect to fig. 10, can be used with communication system 900 to reduce collisions and interference in unlicensed mixed spectrum scenarios.

Note that the RTS and CTS messages, in addition to helping to prevent potential collisions and resulting interference, help to improve power management and improve Clear Channel Assessment (CCA)/enhanced CCA (ecca) procedures. For example, according to some embodiments, an RTS frame may include five fields, including frame control, duration, receiver address, transmitter address, and frame check sequence. Similarly, according to some embodiments, a CTS frame may include four fields, including frame control, duration, receiver address, and frame check sequence. The duration and intended recipient information may be used to allow the receiver of the unintended recipient to put its RF into a lower power mode (e.g., sleep) for the duration of the communication and incorporate the duration of the idle mode into its CCA/eCCA procedure.

Fig. 10-LAA communication using dynamic RTS/CTS

LAA today has no inherent solution for hidden nodes and more generally provides limited functionality for assisting Wi-Fi nodes sharing a wireless medium to reduce power consumption. Thus, integrating the use of RTS/CTS into LAA communication technology may alleviate potential problems caused by hidden nodes, improve power consumption characteristics of neighboring Wi-Fi and LAA devices, and more generally improve coexistence situations between such devices. Fig. 10 is a flow diagram illustrating a method for a wireless device (e.g., a cellular base station or a wireless User Equipment (UE) device) to perform LAA communication in a manner that opportunistically introduces the use of RTS and CTS messages, in accordance with some embodiments of the present invention.

The aspects of the method of fig. 10 may be implemented by a cellular base station, such as BS 102 shown and described in the various figures herein, or more generally may be used in conjunction with any of the computer systems or devices shown in the above figures, as desired. It is noted that while at least some elements of the method of fig. 10 are described in a manner directed to using communication techniques and/or features associated with LAA and/or 3GPP specification documents, such description is not intended to limit the disclosure and aspects of the method of fig. 10 may be used in any suitable wireless communication system as desired. In various embodiments, some of the illustrated method elements may be performed concurrently, in a different order than illustrated, may be replaced by other method elements, or may be omitted. Additional method components may also be performed as desired. As shown, the method may operate as follows.

At 1002, a Listen Before Talk (LBT) procedure may be performed by a wireless device to determine whether a wireless medium is available. According to some embodiments, the wireless device may perform an LBT procedure to ensure that the wireless medium is available for LAA communication (or another cellular communication technology that communicates using unlicensed spectrum). For example, the wireless device may be a base station providing the SCell on a wireless medium, which may be a channel in a 5GHz unlicensed band or any other desired wireless medium shared with other wireless devices that communicate independently with a network operator controlling the base station.

The LBT process may operate in a similar manner as shown and described in fig. 8, or in another manner as desired. The LBT procedure may include monitoring the wireless medium to determine whether any transmissions are already in progress by: for example, by detecting that the signal strength on the wireless medium is above a certain threshold that is considered to indicate an ongoing transmission, by detecting a cyclic signal pattern associated with a preamble/prefix signal that is intended to indicate the presence of a transmission, and/or by performing other transmission detection techniques. The LBT procedure may also include not transmitting if it is determined that an existing transmission is in progress, and may be used to help reduce the number of collisions occurring on the wireless medium. According to some embodiments (e.g., according to the exemplary procedure of fig. 8), the LBT procedure may require clearing of the wireless medium for at least a minimum length of time before the procedure can be considered successful.

Once the LBT procedure is successful, the wireless device may utilize the wireless medium for wireless communication. For some wireless communication technologies, such as Wi-Fi, data transmission may begin immediately upon successful completion of LBT. However, for other wireless communication technologies, such as many cellular communication technologies (e.g., including LTE-LAA), timing synchronization schemes defining possible data communication windows may be used. For example, as previously described, in some cases, LTE-LAA communications may include a frame structure in which each frame includes 10 subframes, each subframe including 2 slots, for a total of 20 slots in each radio frame. In this case, LAA communication may start only at slot boundaries (or possibly even only at subframe boundaries) for synchronization reasons, at least according to some embodiments.

Since the LBT procedure may be started at any time and may be of an indeterminate length (e.g., since successful completion of the procedure may depend on the use of the wireless medium, or the absence of other wireless devices during the LBT procedure), it may generally happen that there is an interval between successful completion of the LBT procedure and the next possible start time for LAA communication by the wireless device. Since the wireless medium may be used by another wireless device if it is not occupied during the interval, the wireless device may occupy the wireless medium in one way or another during the time period, e.g., to effectively reserve the wireless medium until it can be used for LAA communication.

At 1004, an amount of time between successful completion of the LBT procedure and a next possible start time (e.g., a next subframe or possibly a next slot) for LAA communication may be determined. In other words, the wireless device may calculate how long the time between the point in time that the device may control the wireless medium due to successful completion of the LBT procedure and the point in time that the device may utilize the wireless medium for LAA communication.

At 1006, the wireless device can determine a manner in which the device will occupy the wireless medium between successfully completing the LBT procedure and the next possible start time for LAA communication. The manner in which the wireless medium is occupied may include transmission of a "reservation signal," which may include noise, cell-specific reference signals (CRS), and/or any other desired type of signal, which is detected to indicate that the wireless medium is occupied by other wireless devices within communication range of the wireless device.

According to some embodiments, the manner in which the wireless medium is occupied may be determined based at least in part on an amount of time between successful completion of the LBT procedure and a next possible start time for LAA communication over the wireless medium. As one possibility, the time between completing LBT and beginning LAA communication can be exploited in an opportunistic manner to help mitigate potential interference caused by hidden nodes. For example, according to some embodiments, the time between completing LBT and beginning LAA communication may be used for RTS/CTS handshaking if it is sufficient to do so, or for CTS-to-self messages if it is sufficient to transmit but not sufficient to do so.

According to some embodiments, the manner in which the wireless medium is occupied may also be determined based at least in part on whether an intended recipient of the LAA communication supports RTS/CTS handshaking (e.g., is capable of CTS signaling). For example, to enable a wireless device to initiate an RTS/CTS handshake during the interval between completion of LBT and initiation of LAA communication, it may be important that the intended recipient be able to support RTS/CTS signaling, e.g., to be able to respond to an RTS message with a CTS message. Support for such signaling may include being able to recognize that it is the intended recipient indicated in the RTS message and respond with a CTS immediately (i.e., after a short inter-frame space). The CTS may be transmitted by the LAA transmission front end using the LAA channel (e.g., after which the front end may switch back to a receive mode in order to receive a Physical Downlink Control Channel (PDCCH) and/or a Physical Downlink Shared Channel (PDSCH)). Alternatively (e.g., if the intended recipient does not have an LAA transmission front end, such as if it is configured for LAA downlink only), the intended recipient may transmit a CTS message in the LAA channel (or possibly in one of the closely corresponding Wi-Fi channels) using a Wi-Fi interface. A Wi-Fi transmission of a CTS message may be triggered after receiving an RTS message using an LAA interface using a real-time coexistence interface (e.g., between a Wi-Fi module and an LAA module). Thus, in at least some cases, the wireless device may also determine whether the intended recipient of the LAA communication supports an RTS/CTS handshake.

In this case, as an alternative example, if there is sufficient time to transmit the CTS-to-self message, and even sufficient time for the RTS/CTS handshake to proceed, the time between completing the LBT and beginning the LAA communication may be used to transmit the CTS-to-self message, e.g., if the intended recipient of the LAA communication is not configured (or unaware that it is configured) to respond with a CTS message as part of the RTS/CTS handshake (if needed). Alternatively or in addition to using the CTS-to-self message, the time between completing the LBT and beginning LAA communication may be used to send only the Wi-Fi preamble, e.g., including a PHY frame header indicating the transmission duration and potentially not requiring Media Access Control (MAC) frame header decoding (as in the case of the RTS/CTS message), or other Wi-Fi based signaling indicating the Network Allocation Vector (NAV)/duration of the transmission.

According to some embodiments, the time between completing LBT and beginning LAA communication may be occupied only by a reservation signal that does not include an RTS or CTS message or a Wi-Fi preamble/NAV if the time is not sufficient for both an RTS/CTS handshake and a CTS-to-self message or Wi-Fi preamble/NAV to be transmitted. Alternatively, if there is not enough time to perform the RTS/CTS handshake between completion of the LBT and the next possible start time for the LAA communication (or there may not be enough time to transmit the CTS-to-self or Wi-Fi preamble/NAV message), the wireless device may delay the LAA communication until the subsequent possible start time for the LAA communication and may perform the RTS/CTS handshake (or provide the CTS-to-self or Wi-Fi preamble/NAV message) using additional time to delay the LAA communication.

The overall relative frequency at which the RTS/CTS handshake is performed, the CTS-to-self message or the Wi-Fi preamble/NAV is transmitted, or neither, during the interval between completion of the LBT and commencement of the LAA communication may depend, at least in part, on the typical length of time required to perform the RTS/CTS handshake and transmit the CTS-to-self or Wi-Fi preamble/NAV messages, and the length of time between LAA communication opportunity. However, at least according to some embodiments, these variables may work together such that the RTS/CTS handshake may be performed on most (and possibly even most) occasions. For example, as one possibility, consider a case where LAA communication may begin every slot, in which case each slot may occur once every 500 μ s, and where a full preamble/RTS/SIFS/preamble/CTS exchange may typically require approximately 100-. Assuming that the LBT procedure can be completed in any number of microseconds between 0 and 500 until the next time slot has an equal probability, there may be at least a 70% chance in this case that there is sufficient time to perform the RTS/CTS handshake before the next time slot begins. This probability may rise to at least 85% if LAA communication can start every subframe, which may occur, for example, once every 1 ms. As will be appreciated, other lengths of time for the RTS/CTS handshake and CTS-to-self messages, as well as other intervals between LAA communication opportunities, and the associated likelihood that there will be sufficient time to perform the RTS/CTS handshake or CTS-to-self after the LBT procedure is completed before the next LAA communication opportunity begins, are also possible.

At 1008, the wireless medium may be engaged between successful completion of the LBT procedure and a next possible start time for LAA communication in the determined manner. For example, in accordance with at least some embodiments, if the amount of time between successful completion of the LBT procedure and the next possible start time for the LAA communication is at least equal to the amount of time to transmit a Request To Send (RTS) message and receive a Clear To Send (CTS) message after the inter-frame space, the wireless device may transmit an RTS message and receive a CTS message (e.g., from the intended recipient of the LAA communication) in response to the RTS message. Further, if the amount of time between successful completion of the LBT procedure and the next possible start time of the LAA communication is greater than the amount of time to transmit the RTS message and receive the CTS message after the inter-frame gap, the wireless device may also transmit a reservation signal until the remaining time before the next possible start time of the LAA communication is equal to the amount of time to transmit the RTS message and receive the CTS message after the inter-frame gap.

The wireless device may transmit a CTS-to-self message (or Wi-Fi preamble/NAV message) if the amount of time between successful completion of the LBT procedure and the next possible start time for the LAA communication is less than the amount of time to transmit a Request To Send (RTS) message and receive a Clear To Send (CTS) message after the inter-frame space, but at least equal to the amount of time to transmit a CTS-to-self message (or possibly at least equal to the amount of time to transmit a Wi-Fi preamble/NAV message). Further, if the amount of time between successful completion of the LBT procedure and the next possible start time of the LAA communication is less than the amount of time to transmit the RTS message and receive the CTS message after the inter-frame interval, but greater than the amount of time to transmit the CTS-to-self message (or possible Wi-Fi preamble/NAV message), the wireless device may also transmit a reservation signal until the remaining time before the next possible start time of the LAA communication is equal to the amount of time to transmit the CTS-to-self message (or Wi-Fi preamble/NAV message).

If the amount of time between successful completion of the LBT procedure and the next possible start time of the LAA communication is less than the amount of time to transmit the CTS-to-self message (or possible Wi-Fi preamble/NAV message), the wireless device may transmit a reservation signal (e.g., while not performing an RTS/CTS handshake or transmitting a CTS-to-self or Wi-Fi preamble/NAV message) until the next possible start time of the LAA communication.

At 1010, LAA communication can be performed over the wireless medium at a next possible start time of the LAA communication. This may include transmitting data to one or more receiving devices using PDSCH (and possibly PDCCH transmission signaling/control information, e.g., if scheduled using the same carrier) during one or more LAA subframes/time slots.

Since the wireless device may have exchanged RTS/CTS messages with (e.g., may be underutilized) an interval between successful completion of the LBT procedure and LAA communication, the hidden node may detect the CTS message transmitted by the intended recipient of the LAA communication, and thus the likelihood of the hidden node (i.e., with respect to the wireless device) attempting to perform a transmission during the LAA communication may be reduced, even if the hidden node itself is unable to detect the RTS message or the LAA communication. Further, since the transmissions of the RTS and CTS messages may include Wi-Fi preambles, they may be more detectable for certain nodes (e.g., capable of detecting transmissions based on cyclic prefix even though they may not be able to detect transmissions based on signal strength alone) than LAA communications. Notably, this benefit may apply even if the wireless device transmits only CTS-to-self messages or Wi-Fi preambles/NAVs during the interval, at least according to some embodiments, and thus may reduce the chance of collisions interfering with LAA communications even though it may not be as efficient as a full RTS/CTS handshake.

FIG. 11-FIG. 13-LAA communication timeline

Fig. 11-13 illustrate various possible LAA communication timelines according to which a wireless device may operate, for example, in conjunction with the method of fig. 10. Fig. 11 shows an exemplary timeline 1100 in which the interval between LAA LBTs is occupied by a wireless device (shown as an eNB in the illustrated figure) by transmitting LAA reservation signal (e.g., noise, etc.) without using RTS/CTS handshaking or CTS-to-self. This timeline may be used, for example, if there is not enough time between completion of LAA LBT and the start of PDCCH for the next LAA subframe for either the CTS-to-self message or the full RTS/CTS handshake.

Fig. 12 shows an exemplary timeline 1200 in which the wireless medium is occupied by LAA reservation signals (e.g., noise, etc.) until the time remaining until the start of the next LAA subframe is just enough to transmit a CTS-to-self, at which time the wireless device (represented as eNB in the shown figure) may transmit the CTS-to-self. The intended recipient (shown as a UE in the illustration) may receive the CTS-to-self and prepare to receive. Other wireless devices within range (shown as another Wi-Fi station in the illustrated figure) may also receive the CTS-to-self and may determine to discontinue their current LBT procedure (e.g., if applicable) and stay asleep for the duration of LAA communication (e.g., as indicated by the CTS-to-self). This timeline may be used, for example, if there is not enough time between completion of LAA LBT and the start of PDCCH for the next LAA subframe for a full RTS/CTS handshake, but enough time for transmission of CTS-to-self.

Fig. 13 illustrates an example timeline 1300 in which the wireless medium is occupied by an LAA reservation signal (e.g., noise, etc.) until the time remaining until the start of the next LAA subframe is just sufficient for an RTS/CTS handshake, e.g., including the time to transmit an RTS message (e.g., by the wireless device), a short inter-frame space (SIFS), and the time to transmit a CTS message (e.g., by the intended recipient of the LAA communication), at which time the wireless device (shown as an eNB in the illustrated figure) may transmit the RTS message. The intended recipient (denoted UE in the illustrated illustration) may receive the RTS message and may respond with a CTS message after SIFS. Other wireless devices within range (shown as another Wi-Fi station in the illustrated figure) may also receive the CTS (and/or RTS), and may determine to interrupt their current LBT procedure (e.g., if applicable) and stay asleep for the duration of LAA communications (e.g., as indicated by RTS and CTS). This timeline may be used, for example, if there is sufficient time between completion of LAA LBT and the start of PDCCH for the next LAA subframe for a full RTS/CTS handshake.

Additional exemplary embodiments are provided below.

One set of embodiments can include an apparatus comprising: a processing element configured to cause a wireless device to: performing a Listen Before Talk (LBT) procedure to determine whether a wireless medium is available, wherein the wireless medium includes an unlicensed spectrum; determining, when the LBT procedure is complete, an amount of time according to a timing synchronization scheme of the cellular communication system until a next possible start time for communicating in the cellular communication system; seizing the wireless medium until a next possible start time for communicating in the cellular communication system in a manner selected based at least in part on an amount of time until the next possible start time for communicating in the cellular communication system; and performing cellular communication over the wireless medium at a next possible start time for communicating in the cellular communication system.

According to some embodiments, the wireless medium is occupied by one or more of the following until a next possible start time for communicating in the cellular communication system: a Request To Send (RTS)/Clear To Send (CTS) handshake procedure, a CTS-to-self message, a Wi-Fi preamble/NAV, or a reservation signal.

According to some embodiments, wherein if the amount of time until the next possible start time for LAA communication is greater than the estimated amount of time to complete the RTS/CTS handshake procedure, the wireless medium is occupied by at least one RTS/CTS handshake procedure until the next possible start time for communicating in the cellular communication system.

According to some embodiments, if the amount of time until the next possible start time for communicating in the cellular communication system is greater than the estimated amount of time for transmitting the CTS-to-self or Wi-Fi preamble/NAV message and less than the estimated amount of time for completing the RTS/CTS handshake procedure, the wireless medium is occupied by at least the CTS-to-self or Wi-Fi preamble/NAV message until the next possible start time for communicating in the cellular communication system.

According to some embodiments, if the amount of time until the next possible start time for communicating in the cellular communication system is less than the estimated amount of time to complete the RTS/CTS handshake procedure or less than the estimated amount of time to send a CTS-to-self or Wi-Fi preamble/NAV, the wireless medium is occupied by a reservation signal until the next possible start time for communicating in the cellular communication system and is not occupied by the RTS/CTS handshake procedure or the CTS-to-self or Wi-Fi preamble/NAV message.

According to some embodiments, the manner in which the wireless medium is occupied until the next possible start time for communicating in the cellular communication system is further selected based at least in part on whether an intended recipient of the cellular communication supports a Request To Send (RTS)/Clear To Send (CTS) handshake procedure.

According to some embodiments, the next possible start time for communicating in the cellular communication system comprises a next subframe according to a timing synchronization scheme of the cellular communication system.

According to some embodiments, the next possible start time for communicating in the cellular communication system comprises a next time slot according to a timing synchronization scheme of the cellular communication system.

Another set of embodiments may include a method comprising: by a wireless device: performing a Listen Before Talk (LBT) procedure to determine whether a wireless medium is available; determining an amount of time between successfully completing an LBT procedure and a next possible start time for authorized assisted access (LAA) communication; determining a manner of occupying the wireless medium between successfully completing the LBT procedure and a next possible start time of the LAA communication over the wireless medium based, at least in part, on an amount of time between successfully completing the LBT procedure and the next possible start time of the LAA communication over the wireless medium; seizing the wireless medium between successful completion of the LBT procedure and a next possible start time of the LAA communication in the determined manner; and performing the LAA communication over the wireless medium at a next possible start time of the LAA communication.

According to some embodiments, if the amount of time between successful completion of the LBT procedure and the next possible start time for LAA communication is at least equal to the amount of time to transmit a Request To Send (RTS) message and receive a Clear To Send (CTS) message after an inter-frame space, the manner of determining comprises: transmitting an RTS message; and receiving the CTS message.

According to some embodiments, if the amount of time between successful completion of the LBT procedure and the next possible start time for LAA communication is greater than the amount of time to transmit the RTS message and receive the CTS message after the inter-frame space, then determining further comprises: the reservation signal is transmitted for a remaining time until the next possible start time for LAA communication equal to the amount of time to transmit the RTS message and receive the CTS message after the inter-frame space.

According to some embodiments, if the amount of time between successful completion of the LBT procedure and the next possible start time for LAA communication is less than the amount of time to transmit a Request To Send (RTS) message and receive a Clear To Send (CTS) message after an inter-frame space, but at least equal to the amount of time to transmit a CTS-to-self or Wi-Fi preamble/NAV message, then determining comprises: a CTS-to-self or Wi-Fi preamble/NAV message is transmitted.

According to some embodiments, if the amount of time between successful completion of the LBT procedure and the next possible start time for LAA communication is less than the amount of time to transmit the RTS message and receive the CTS message after the inter-frame space, but greater than the amount of time to transmit the CTS-to-self or Wi-Fi preamble/NAV message, then the manner of determining further comprises: the reservation signal is transmitted for an amount of time remaining until the next possible start time of the LAA communication equal to the amount of time the CTS-to-self or Wi-Fi preamble/NAV message is transmitted.

According to some embodiments, if the amount of time between successful completion of the LBT procedure and the next possible start time of LAA communication is less than the amount of time to transmit the CTS-to-self or Wi-Fi preamble/NAV message, the manner of determining comprises: the reservation signal is transmitted until the next possible start time of the LAA communication.

According to some embodiments, the next possible start time of LAA communication includes one or more of: the next subframe according to the LAA timing synchronization scheme, or the next slot according to the LAA timing synchronization scheme.

Yet another set of implementations can include a wireless apparatus comprising: an antenna; a radio operatively coupled to the antenna; and a processing element operatively coupled to the radio component; wherein the antenna, radio and processing element are configured to: performing a Listen Before Talk (LBT) procedure to determine whether a wireless medium is available; determining an amount of time between successful completion of an LBT procedure and a next subframe start time for a grant assisted access (LAA) communication; and transmitting a Request To Send (RTS) message prior to a next subframe start time of the LAA communication based at least in part on an amount of time between successful completion of the LBT procedure and the next subframe start time being above a first predetermined threshold, wherein the RTS message is not transmitted if the amount of time between successful completion of the LBT procedure and the next subframe start time is below the first predetermined threshold.

According to some embodiments, the antenna, the radio and the processing element are further configured to: determining whether an intended recipient of the LAA communication supports signaling of a clear-to-send (CTS) message; and further transmit an RTS message prior to a next subframe start time of the LAA communication based at least in part on the signaling that the intended recipient of the LAA communication supports the CTS message, wherein the RTS message is not transmitted if the intended recipient of the LAA communication does not support the signaling of the CTS message.

According to some embodiments, the antenna, the radio and the processing element are further configured to: a clear to send message from an intended recipient of the LAA communication is received in response to the RTS message between successful completion of the LBT procedure and the next subframe start time.

According to some embodiments, the antenna, the radio and the processing element are further configured to: transmitting a Clear To Send (CTS) to local (CTS-to-self) or Wi-Fi preamble/NAV message prior to a next subframe start time of the LAA communication based at least in part on an amount of time between successful completion of the LBT procedure and the next subframe start time being below a first predetermined threshold and above a second predetermined threshold, wherein the CTS-to-self or Wi-Fi preamble/NAV message is not transmitted if the amount of time between successful completion of the LBT procedure and the next subframe start time is below the second predetermined threshold.

According to some embodiments, the wireless device comprises a cellular base station.

Another set of exemplary embodiments may include a non-transitory computer accessible memory medium including program instructions that, when executed on a device, cause the device to implement any or all of the portions of any of the preceding examples.

Another set of exemplary embodiments may include a computer program comprising instructions for performing any or all of the portions of any of the preceding examples.

Yet another exemplary set of embodiments may comprise an apparatus comprising means for performing any or all of the elements of any of the preceding examples.

Embodiments of the invention may be implemented in any of various forms. For example, in some embodiments, the invention may be implemented as a computer-implemented method, a computer-readable memory medium, or a computer system. In other embodiments, the invention may be implemented using one or more custom designed hardware devices, such as ASICs. In other embodiments, the invention may be implemented using one or more programmable hardware elements, such as FPGAs.

In some embodiments, a non-transitory computer-readable memory medium (e.g., a non-transitory memory element) may be configured such that it stores program instructions and/or data, wherein the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets.

In some embodiments, a device (e.g., a UE) may be configured to include a processor (or a set of processors) and a memory medium (or memory element), wherein the memory medium stores program instructions, wherein the processor is configured to read and execute the program instructions from the memory medium, wherein the program instructions are executable to implement any of the various method embodiments described herein (or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets). The apparatus may be embodied in any of a variety of forms.

Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims (22)

1. An apparatus for cellular communication, comprising:

a processing element configured to cause a wireless device to:

performing a listen-before-talk, LBT, procedure that occupies an indeterminate amount of time to determine when to begin transmitting on a wireless medium, wherein the wireless medium comprises an unlicensed spectrum;

determining, when the LBT procedure is complete, an amount of time according to a timing synchronization scheme of a cellular communication system until a next possible start time for communicating in the cellular communication system;

occupying the wireless medium until the next possible start time for communicating in the cellular communication system in a manner selected based at least in part on the amount of time until the next possible start time for communicating in the cellular communication system, wherein the wireless medium is occupied at least in part by transmitting a cell-specific reference signal, CRS, until the next possible start time for communicating in the cellular communication system, wherein in response to determining that the amount of time until the next possible start time for cellular communication is greater than an estimated amount of time to complete a request to send, RTS, clear to send, CTS, handshake process, the wireless medium is also occupied by at least the RTS/CTS handshake process until the next possible start time for communicating in the cellular communication system, wherein RTS of the RTS/CTS handshake procedures is transmitted using cellular and CTS of the RTS/CTS handshake procedures is received using Wi-Fi; and

performing cellular communication over the wireless medium at the next possible start time for communicating in the cellular communication system.

2. The apparatus of claim 1, wherein the processing element is further configured to cause the wireless device to, at a later time:

performing a second LBT procedure;

determining, when the second LBT procedure is completed, an amount of time according to a timing synchronization scheme of a cellular communication system up to a further possible start time for communicating in the cellular communication system; and

occupying the wireless medium until the further possible start time for communicating in the cellular communication system by one or more of:

a second RTS/CTS handshake procedure;

a CTS-to-self message;

Wi-Fi preamble/NAV; or

The signal is reserved.

3. The apparatus of claim 2, wherein the first and second electrodes are disposed in a common plane,

wherein the wireless medium is further occupied by at least a second RTS/CTS handshake process until the further possible start time for communicating in the cellular communication system if an amount of time until the further possible start time for cellular communication is greater than an estimated amount of time to complete the second RTS/CTS handshake process.

4. The apparatus of claim 2, wherein the first and second electrodes are disposed in a common plane,

wherein the wireless medium is further occupied by at least a CTS-to-self or a Wi-Fi preamble/NAV message until the further possible start time for communicating in the cellular communication system if an amount of time until the further possible start time for communicating in the cellular communication system is greater than an estimated amount of time for transmitting the CTS-to-self or Wi-Fi preamble/NAV message and less than an estimated amount of time for completing a second RTS/CTS handshake procedure.

5. The apparatus of claim 2, wherein the first and second electrodes are disposed in a common plane,

wherein the wireless medium is further occupied by a reservation signal until the further possible start time of communicating in the cellular communication system and is not occupied by a second RTS/CTS handshake procedure or the CTS-to-self or the Wi-Fi preamble/NAV message if the amount of time until the further possible start time of communicating in the cellular communication system is less than an estimated amount of time to complete a second RTS/CTS handshake procedure or less than an estimated amount of time to transmit a CTS-to-self message or a Wi-Fi preamble/NAV.

6. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,

the manner in which the wireless medium is occupied until the next possible start time for communicating in the cellular communication system is further selected based at least in part on whether an intended recipient of the cellular communication supports the RTS/CTS handshake procedure.

7. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,

wherein the next possible start time for communicating in the cellular communication system comprises a next subframe according to the timing synchronization scheme of the cellular communication system.

8. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,

wherein the next possible start time for communicating in the cellular communication system comprises a next time slot according to the timing synchronization scheme of the cellular communication system.

9. The apparatus of claim 6, wherein the first and second electrodes are disposed on opposite sides of the substrate,

wherein the processing element is further configured to cause the wireless device to:

transmitting the RTS message prior to the next possible start time for communicating in the cellular communication system based at least in part on the intended recipient of the cellular communication supporting an RTS/CTS handshake procedure,

wherein the next possible start time for communicating in the cellular communication system comprises a next subframe.

10. The apparatus of claim 9, wherein the first and second electrodes are disposed on opposite sides of the substrate,

wherein the processing element is further configured to cause the wireless device to:

receiving a CTS message from the intended recipient of the cellular communication in response to the RTS message between successful completion of the LBT procedure and the next subframe.

11. The apparatus of claim 7, wherein the first and second electrodes are disposed on opposite sides of the substrate,

wherein the processing element is further configured to cause the wireless device to:

transmitting a clear-to-send to native CTS-to-self or Wi-Fi preamble/NAV message prior to the next subframe based, at least in part, on an amount of time between successful completion of the LBT procedure and the next possible start time for communicating in the cellular communication system being below a first predetermined threshold and above a second predetermined threshold,

wherein a CTS-to-self or Wi-Fi preamble/NAV message is not transmitted if the amount of time between successful completion of the LBT procedure and the next possible start time for communication in the cellular communication system is below the second predetermined threshold.

12. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,

wherein the wireless device comprises a cellular base station.

13. The apparatus of claim 1, further comprising:

a radio operatively connected to the processing element.

14. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,

wherein the wireless medium is further occupied by transmission of noise until the next possible start time for communication in the cellular communication system.

15. A method for cellular communications, comprising:

by a wireless device:

performing a listen-before-talk, LBT, procedure that occupies an indeterminate amount of time to determine when to begin transmitting on a wireless medium;

determining an amount of time between successful completion of the LBT procedure and a next possible start time for cellular communication;

occupying the wireless medium until the next possible start time for communicating in the cellular communication system in a manner selected based at least in part on the amount of time until the next possible start time for communicating in the cellular communication system, wherein the wireless medium is occupied at least in part by transmitting a cell-specific reference signal, CRS, until the next possible start time for communicating in the cellular communication system, wherein in response to determining that the amount of time until the next possible start time for cellular communication is greater than an estimated amount of time to complete a request to send, RTS, clear to send, CTS, handshake process, the wireless medium is also occupied at least by the RTS/CTS handshake process until the next possible start time for communicating in the cellular communication system, wherein RTS in the RTS/CTS handshake process is transmitted using cellular and the RTS/CTS is transmitted The CTS in the handshake procedure is received using Wi-Fi; and

performing cellular communication over the wireless medium at the next possible start time of cellular communication.

16. The method of claim 15, further comprising, at a later time:

performing a second LBT procedure;

determining, when the second LBT procedure is completed, an amount of time according to a timing synchronization scheme of a cellular communication system up to a further possible start time for communicating in the cellular communication system; and

based on the amount of time, determining a manner of occupying the wireless medium until the further possible start time for cellular communication.

17. The method of claim 16, wherein if an amount of time until the further possible start time for cellular communication is at least equal to an amount of time to transmit a second RTS message and receive a second CTS message after an inter-frame space, the determined manner comprises:

transmitting a second RTS message; and

a second CTS message is received.

18. The method of claim 17, wherein the first and second light sources are selected from the group consisting of,

wherein if the amount of time until the further possible start time for cellular communication is greater than the amount of time to transmit the second RTS message and receive the second CTS message after the inter-frame space, the determined manner further comprises:

transmitting a reservation signal until an amount of time remaining before the further possible start time for cellular communication equals an amount of time to transmit a second RTS message and to receive a second CTS message after an inter-frame space.

19. The method of claim 16, wherein the first and second light sources are selected from the group consisting of,

wherein if the amount of time until the further possible start time for cellular communication is less than the amount of time to transmit the second RTS message and to receive the second CTS message after the inter-frame space but at least equal to the amount of time to transmit the CTS-to-self or Wi-Fi preamble/NAV messages, the determined manner comprises:

a CTS-to-self or Wi-Fi preamble/NAV message is transmitted.

20. The method of claim 19, wherein the first and second portions are selected from the group consisting of,

wherein if the amount of time until the further possible start time for cellular communication is less than the amount of time to transmit the RTS message and to receive the CTS message after the inter-frame space but greater than the amount of time to transmit the CTS-to-self or Wi-Fi preamble/NAV messages, then the determined manner further comprises:

transmitting a reservation signal until an amount of time remaining before the yet another possible start time for cellular communication is equal to an amount of time to transmit a CTS-to-self or Wi-Fi preamble/NAV message.

21. The method of claim 16, wherein the first and second light sources are selected from the group consisting of,

wherein if the amount of time until the further possible start time for cellular communication is less than the amount of time to transmit a CTS-to-self or Wi-Fi preamble/NAV message, the determined manner comprises:

transmitting a reservation signal until the further possible start time for cellular communication.

22. The method of claim 16, wherein the first and second light sources are selected from the group consisting of,

wherein the yet another possible start time for cellular communication comprises one or more of:

next subframe according to cellular timing synchronization scheme, or

The next time slot according to the cellular timing synchronization scheme.

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