Evolved Machine Type Communication Design for Shared RF Spectrum Operation

Abstract

Various aspects of the present disclosure provide techniques for utilizing a shared radio frequency spectrum (SRFS) for certain devices, such as machine type communication (MTC) user equipment (UE) and evolved or enhanced MTC (eMTC) UE. An exemplary method, for example, performed by a base station (BS), includes: performing a channel clearness assessment (CCA) for at least a portion of the SRFS including one or more narrowband areas; and after performing the CCA, communicating with at least one MTC UE on at least one of the narrowband areas. A second exemplary method, for example, performed by an MTC UE, generally includes: receiving a resource assignment in a narrowband area of ​​a SRFS frequency band from a BS for the MTC UE to use for communicating with the BS; and communicating with the BS on the narrowband area without performing a CCA for the narrowband area.

Description

[0001] This application is a divisional application of the invention patent application entitled “Evolved Machine Type Communication Design for Shared Radio Frequency Spectrum Operations” with an international application date of March 15, 2016 and application number 201680023196.3 (international application number PCT / US2016 / 022444).

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Application No. 15 / 068,789, filed on March 14, 2016, which in turn claims priority to U.S. Provisional Application No. 62 / 152,768, filed on April 24, 2015, both of which are expressly incorporated herein by reference in their entirety. background

[0004] Public domain

[0005] Certain aspects of the present disclosure relate generally to wireless communications and, more particularly, to evolved or enhanced machine type communication (eMTC) operations in a shared radio frequency spectrum (SRFS).

[0006] Related technical description

[0007] Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, etc. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, third generation partnership project (3GPP) long term evolution (LTE) / LTE-Advanced systems, and orthogonal frequency division multiple access (OFDMA) systems.

[0008] In general, a wireless multiple access communication system can support the communication of multiple wireless terminals simultaneously. Each terminal communicates with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from the base station to the terminal, while the reverse link (or uplink) refers to the communication link from the terminal to the base station. Such communication links can be established via single-input single-output, multiple-input single-output, or multiple-input multiple-output (MIMO) systems.

[0009] A wireless communication network may include several base stations that can support communications for several wireless devices. The wireless devices may include user equipment (UE). Some UEs may be considered machine type communication (MTC) UEs, which may include remote devices that can communicate with a base station, another remote device, or some other entity. Machine type communication (MTC) may refer to communication involving at least one remote device on at least one end of the communication, and may include a form of data communication involving one or more entities that do not necessarily require human-computer interaction. MTC UEs may include UEs capable of MTC communications with an MTC server and / or other MTC devices via, for example, a public land mobile network (PLMN).

[0010] Shared Radio Frequency Spectrum (SRFS) includes unlicensed radio frequency spectrum and can therefore be used by a large and diverse range of devices, including, for example, Wi-Fi devices operating according to versions of the IEEE 802.11 standard. Devices utilizing SRFS can perform listen-before-talk (LBT) operations. LBT is generally an operation of receiving on a frequency band for a short period of time and determining that no other device is transmitting on the frequency band before transmitting on the frequency band.

[0011] Overview

[0012] Certain aspects of the present disclosure provide techniques and apparatus for utilizing shared radio frequency spectrum (SRFS) for certain devices, such as machine type communication (MTC) UEs and evolved machine type communication (eMTC) UEs.

[0013] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS) using a shared radio frequency spectrum (SRFS) band. The method generally includes: performing a channel clearness assessment (CCA) for at least a portion of the SRFS including one or more narrowband areas; and after performing the CCA, communicating with at least one machine type communication (MTC) user equipment (UE) on at least one of the narrowband areas.

[0014] Certain aspects of the present disclosure provide a method for wireless communication by a machine type communication (MTC) user equipment (UE) using a shared radio frequency spectrum (SRFS) band. The method generally includes: receiving a resource assignment in a narrowband region of the SRFS band from a base station (BS) for the MTC UE to use for communicating with the BS; and communicating with the BS over the narrowband region without performing a clear channel assessment (CCA) for the narrowband region.

[0015] Certain aspects of the present disclosure provide a method for wireless communication by a machine type communication (MTC) user equipment (UE) using a shared radio frequency spectrum (SRFS) band. The method generally includes: performing a clear channel assessment (CCA) for a narrowband region of the SRFS band; and communicating with a base station (BS) over the narrowband region.

[0016] Certain aspects of the present disclosure provide an apparatus for wireless communication using a shared radio frequency spectrum (SRFS) band. The apparatus generally includes at least one processor configured to: perform a channel clear assessment (CCA) for at least a portion of the SRFS including one or more narrowband areas; and after performing the CCA, communicate with at least one machine type communication (MTC) user equipment (UE) on at least one of the narrowband areas. The apparatus may further include a memory coupled to the at least one processor.

[0017] Certain aspects of the present disclosure provide an apparatus for wireless communication using a shared radio frequency spectrum (SRFS) band. The apparatus generally includes at least one processor configured to: receive a resource assignment in a narrowband region of the SRFS band from a base station (BS) for an MTC UE to use for communicating with the BS; and communicate with the BS over the narrowband region without performing a clear channel assessment (CCA) for the narrowband region. The apparatus may further include a memory coupled to the at least one processor.

[0018] Certain aspects of the present disclosure provide an apparatus for wireless communication using a shared radio frequency spectrum (SRFS) band. The apparatus generally includes at least one processor configured to: perform a clear channel assessment (CCA) for a narrowband region of the SRFS band; and communicate with a base station (BS) over the narrowband region. The apparatus may further include a memory coupled to the at least one processor.

[0019] Certain aspects of the present disclosure provide an apparatus for wireless communication using a shared radio frequency spectrum (SRFS) band. The apparatus generally includes: a device for performing a channel clear assessment (CCA) for at least a portion of the SRFS including one or more narrowband areas; and a device for communicating with at least one machine type communication (MTC) user equipment (UE) on at least one of the narrowband areas after performing the CCA.

[0020] Certain aspects of the present disclosure provide an apparatus for wireless communication using a shared radio frequency spectrum (SRFS) band. The apparatus generally includes: a device for receiving a resource assignment in a narrowband region of the SRFS band from a base station (BS) for an MTC UE to use for communicating with the BS; and a device for communicating with the BS over the narrowband region without performing a clear channel assessment (CCA) for the narrowband region.

[0021] Certain aspects of the present disclosure provide an apparatus for wireless communication using a shared radio frequency spectrum (SRFS) band. The apparatus generally includes: a device for performing a clear channel assessment (CCA) for a narrowband region of the SRFS band; and a device for communicating with a base station (BS) over the narrowband region.

[0022] Certain aspects of the present disclosure provide a computer-readable medium storing computer executable code. The computer executable code generally includes: code for performing a channel clear assessment (CCA) for at least a portion of an SRFS including one or more narrowband areas; and code for communicating with at least one machine type communication (MTC) user equipment (UE) on at least one of the narrowband areas after performing the CCA.

[0023] Certain aspects of the present disclosure provide a computer-readable medium storing computer-executable code. The computer-executable code generally includes: code for receiving a resource assignment in a narrowband region of an SRFS frequency band from a base station (BS) for an MTC UE to communicate with the BS; and code for communicating with the BS over the narrowband region without performing a clear channel assessment (CCA) for the narrowband region.

[0024] Certain aspects of the present disclosure provide a computer-readable medium storing computer-executable code. The computer-executable code generally includes: code for performing a clear channel assessment (CCA) for a narrowband region of an SRFS frequency band; and code for communicating with a base station (BS) over the narrowband region. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with certain aspects of the present disclosure.

[0026] Figure 2 Shown is a block diagram conceptually illustrating an example of a base station in communication with a user equipment (UE) in a wireless communication network in accordance with certain aspects of the present disclosure.

[0027] Figure 3 is a block diagram conceptually illustrating an example of a frame structure in a wireless communication network in accordance with certain aspects of the present disclosure.

[0028] Figure 4 is a block diagram conceptually illustrating two exemplary subframe formats with a normal cyclic prefix.

[0029] Figure 5 Exemplary subframe configurations for eMTC are illustrated in accordance with certain aspects of the present disclosure.

[0030] Fig. 6A and 6B An example of MTC coexistence within a broadband system, such as LTE, in accordance with certain aspects of the present disclosure is illustrated.

[0031] Figure 7

[0013] Example operations for wireless communications by a base station (BS) are illustrated in accordance with certain aspects of the present disclosure.

[0032] Figure 8 Example operations for wireless communications by an MTC user equipment (UE) are illustrated in accordance with certain aspects of the present disclosure.

[0033] Fig. 9

[0013] Example operations for wireless communications by an MTC user equipment (UE) are illustrated in accordance with certain aspects of the present disclosure. Detailed Description

[0034] Various aspects of the present disclosure provide techniques that can help enable communication between a base station (BS) and a machine type communication (MTC) based user equipment (UE) using a shared radio frequency spectrum (SRFS). For example, the techniques can provide techniques for reserving a narrowband (e.g., six physical resource blocks (PRBs)) region for communication between the BS and the MTC UE. Techniques for performing a clear channel assessment (CCA) (a type of LBT) when communicating in a narrowband region of the SRFS are also provided.

[0035] As used herein, a "narrowband region" may refer to a 1.08 MHz (e.g., 6 resource blocks (RBs)) narrowband region of a larger system bandwidth and / or a smaller narrowband region (e.g., 180 kHz) of a wider system bandwidth. As used herein, LTE Release 13 (Rel-13) Narrowband Internet of Things (NB-IOT) may refer to a 180 kHz narrowband region of a wider system bandwidth.

[0036] As used herein, "MTC" may refer to machine type communications (such as NB-IOT) or the Internet of Things. MTC UEs generally refer to UEs that communicate via a radio network but are not regularly used to deliver communications directly to users (such as an electric meter that reports electricity usage data to a billing system computer). As used herein, the term "MTC UE" may refer to an MTC UE that utilizes the entire system bandwidth (e.g., an LTE Release 12 (Rel-12) MTC UE), an MTC UE that utilizes a 1.08 MHz narrowband area of ​​a larger system bandwidth (e.g., an LTE Release 13 (Rel-13) enhanced or evolved MTC (eMTC) UE), and / or an MTC UE that utilizes a smaller narrowband area (e.g., 180 kHz) of a wider system bandwidth (e.g., a Rel-13 NB-IOT MTC UE). Although for convenience, various aspects of the present disclosure are described in the form of an MTC UE that utilizes a 1.08 MHz (e.g., 6 RBs) narrowband area of ​​a larger system bandwidth, these descriptions do not limit the present disclosure. Aspects of the present disclosure may be used with MTC UEs utilizing the entire system bandwidth, MTC UEs utilizing 1.08 MHz narrowband regions of a larger system bandwidth, and MTC UEs utilizing smaller narrowband regions (e.g., 180 kHz) of a wider system bandwidth. MTC UEs include devices such as sensors, monitors, meters, location tags, security devices, robots / robotic devices, drones, and the like. To enhance coverage for certain devices (such as MTC UEs), "bundling" may be utilized, where certain transmissions are sent as a transmission bundle (e.g., the same information is transmitted over multiple subframes).

[0037] The techniques described herein may be used for various wireless communication networks, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA), Time Division Synchronous CDMA (TD-SCDMA), and other CDMA variants. cdma200 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network may implement radio technologies such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash- Radio technologies such as LTE and SC-FDMA are used in the UTRA and E-UTRA technologies. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and Advanced LTE (LTE-A) in both frequency division duplex (FDD) and time division duplex (TDD) are new releases of UMTS using E-UTRA, which adopt OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). Cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The technology described herein can be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, certain aspects of these technologies are described below for LTE / Advanced LTE, and LTE / Advanced LTE terms are used in most of the following descriptions. LTE and LTE-A are generally referred to as LTE.

[0038] Figure 1 An example wireless communication network 100 is illustrated in which aspects of the present disclosure may be practiced. For example, the techniques presented herein may be used to assist Figure 1 The UE and the BS shown in FIG. 4 communicate on a machine-type physical downlink control channel (mPDCCH) using a narrowband (eg, six PRBs) based search space.

[0039] The network 100 may be an LTE network or some other wireless network. The wireless network 100 may include a number of evolved Node Bs (eNBs) 110 and other network entities. An eNB is an entity that communicates with a user equipment (UE) and may also be referred to as a base station, a Node B, an access point, etc. Each eNB may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​an eNB and / or an eNB subsystem serving the coverage area, depending on the context in which the term is used.

[0040] An eNB may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a pico cell may be referred to as a pico eNB. An eNB for a femto cell may be referred to as a femto eNB or a home eNB (HeNB). In Figure 1 In the example shown in , eNB 110a may be a macro eNB for macro cell 102a, eNB 110b may be a pico eNB for pico cell 102b, and eNB 110c may be a femto eNB for femto cell 102c. An eNB may support one or more (e.g., three) cells. The terms "eNB," "base station," and "cell" may be used interchangeably herein.

[0041] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., an eNB or UE) and send transmissions of the data to a downstream station (e.g., a UE or eNB). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown in FIG. 1 , a relay station 110 d may communicate with macro eNB 110 a and UE 120 d to facilitate communication between eNB 110 a and UE 120 d. A relay station may also be referred to as a relay eNB, a relay base station, a relay, etc.

[0042] The wireless network 100 may be a heterogeneous network including different types of eNBs (e.g., macro eNBs, pico eNBs, femto eNBs, relay eNBs, etc.). These different types of eNBs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless network 100. For example, a macro eNB may have a high transmit power level (e.g., 5 to 40 watts), while a pico eNB, a femto eNB, and a relay eNB may have a lower transmit power level (e.g., 0.1 to 2 watts).

[0043] A network controller 130 may be coupled to a set of eNBs and may provide coordination and control for these eNBs. The network controller 130 may communicate with each eNB via a backhaul. The eNBs may also communicate with each other, for example, directly or indirectly via a wireless or wired backhaul.

[0044] UE 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. Some examples of UE may include a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a handheld device, a tablet device, a laptop computer, a netbook, a smartbook, an ultrabook, a wearable device (e.g., a smart watch, a smart bracelet, smart clothing, smart glasses, smart goggles, a head-up display), a robot / robotic device, a drone, an entertainment device (e.g., a music player, a gaming device), a camera, a navigation device, a vehicle-mounted device, a medical device, a healthcare device, etc. In Figure 1 In FIG. 1 , a solid line with double arrows indicates desired transmissions between a UE and a serving eNB, which is an eNB designated to serve the UE on the downlink and / or uplink. A dashed line with double arrows indicates potentially interfering transmissions between a UE and an eNB.

[0045] Figure 2 It shows that it can be Figure 1 1. Block diagram of a design of base station / eNB 110 and UE 120 for one of the base stations / eNBs and one of the UEs in the network. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0046] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based on the CQI received from the UE, process (e.g., encode and modulate) the data for the UE based on the MCS selected for each UE, and provide data symbols to all UEs. The transmit processor 220 may also process system information (e.g., for SRPI, etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The processor 220 may also generate reference symbols for reference signals (e.g., CRS) and synchronization signals (e.g., PSS and SSS). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols where applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively.

[0047] At UE 120, antennas 252a to 252r may receive downlink signals from base station 110 and / or other base stations and may provide received signals to demodulators (DEMOD) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) its received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive (RX) processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. A channel processor may determine RSRP, RSSI, RSRQ, CQI, etc.

[0048] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266, where applicable, further processed by modulators 254a through 254r (e.g., for SC-FDM, OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by MIMO detectors 236, where applicable, and further processed by receive processors 238 to obtain decoded data and control information sent by the UE 120. The processor 238 may provide decoded data to a data sink 239 and decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0049] Controllers / processors 240 and 280 may direct the operations at base station 110 and UE 120, respectively. For example, controller / processor 240 and / or other controllers, processors, and modules at base station 110 may perform operations such as directing Figure 7 Similarly, the controller / processor 280 and / or other controllers, processors, and modules at the UE 120 may, for example, perform or direct the operations 700 shown in FIG. Figure 8 The operations 800 and Fig. 9 Operations 900 are shown in FIG. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. Scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0050] Figure 3 An exemplary frame structure 300 for FDD in LTE is shown. The transmission timeline for each of the downlink and uplink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be divided into 10 subframes with indices 0 to 9. Each subframe may include two time slots. Each radio frame may thus include 20 time slots with indices 0 to 19. Each time slot may include L symbol periods, e.g., for a normal cyclic prefix (e.g., Figure 3, or six symbol periods for an extended cyclic prefix. The 2L symbol periods in each subframe may be assigned indices 0 to 2L-1.

[0051] In LTE, an eNB may transmit a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) on the downlink at the center of the system bandwidth for each cell supported by the eNB. The PSS and SSS may be transmitted in symbol periods 6 and 5, respectively, in subframes 0 and 5 of each radio frame with a normal cyclic prefix, as shown in FIG. Figure 3 As shown in . PSS and SSS can be used by UE for cell search and acquisition. The eNB can transmit a cell-specific reference signal (CRS) across the system bandwidth for each cell supported by the eNB. CRS can be transmitted in certain symbol periods of each subframe and can be used by the UE to perform channel estimation, channel quality measurement, and / or other functions. The eNB can also transmit a physical broadcast channel (PBCH) in symbol periods 0 to 3 in slot 1 of certain radio frames. PBCH can carry some system information. The eNB can transmit other system information in certain subframes, such as a system information block (SIB) on a physical downlink shared channel (PDSCH). The eNB can transmit control information / data on a physical downlink control channel (PDCCH) in the first B symbol periods of a subframe, where B can be configurable for each subframe. The eNB can transmit traffic data and / or other data on the PDSCH in the remaining symbol periods of each subframe.

[0052] Figure 4 Two exemplary subframe formats 410 and 420 with normal cyclic prefixes are shown. Available time-frequency resources can be divided into resource blocks. Each resource block can cover 12 subcarriers in a time slot and can include several resource elements. Each resource element can cover one subcarrier in a symbol period and can be used to send a modulation symbol that can be a real value or a complex value.

[0053] Subframe format 410 may be used for two antennas. CRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7, and 11. A reference signal is a signal known a priori to the transmitter and receiver and may also be referred to as a pilot. CRS is a cell-specific reference signal, for example, generated based on a cell identity (ID). Figure 4, for a given resource element with label Ra, a modulation symbol may be transmitted from antenna a on the resource element, and no modulation symbol may be transmitted from other antennas on the resource element. Subframe format 420 may be used with four antennas. CRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7, and 11 and from antennas 2 and 3 in symbol periods 1 and 8. For both subframe formats 410 and 420, CRS may be transmitted on uniformly spaced subcarriers, which may be determined based on the cell ID. CRS may be transmitted on the same or different subcarriers depending on its cell ID. For both subframe formats 410 and 420, resource elements not used for CRS may be used to transmit data (e.g., traffic data, control data, and / or other data).

[0054] The PSS, SSS, CRS and PBCH in LTE are described in the publicly available 3GPP TS 36.211 entitled "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation."

[0055] For FDD in LTE, an interlace structure may be used for each of the downlink and uplink. For example, Q interlaces with indices 0 to Q–1 may be defined, where Q may be equal to 4, 6, 8, 10, or some other value. Each interlace may include subframes spaced apart by Q frames. Specifically, interlace q may include subframes q, q+Q, q+2Q, etc., where q∈{0,…,Q–1}.

[0056] The wireless network may support hybrid automatic repeat request (HARQ) for data transmission on the downlink and uplink. For HARQ, a transmitter (e.g., an eNB) may send one or more transmissions of a packet until the packet is correctly decoded by a receiver (e.g., a UE) or some other termination condition is encountered. For synchronous HARQ, all transmissions of the packet may be sent in each subframe of a single interlace. For asynchronous HARQ, each transmission of the packet may be sent in any subframe.

[0057] A UE may be located within the coverage of multiple eNBs. One of these eNBs may be selected to serve the UE. The serving eNB may be selected based on various criteria such as received signal strength, received signal quality, path loss, etc. Received signal quality may be quantified by signal-to-noise-and-interference ratio (SINR), or reference signal received quality (RSRQ), or some other metric. A UE may operate in a strong interference scenario, where the UE may observe severe interference from one or more interfering eNBs.

[0058] Example control channel design for machine type communications

[0059] As mentioned above, aspects of the present disclosure provide techniques for signaling control channels to machine type communication (MTC) devices that can use narrowband regions of larger system bandwidths. Such narrowband regions can be, for example, Rel-13 eMTC narrowband with a bandwidth of 1.08 MHz (e.g., six RBs) or Rel-13 NB-IOT narrowband with a bandwidth of 180 kHz (e.g., one RB).

[0060] The focus of traditional LTE design (e.g., for legacy "non-MTC" devices) is on improving spectral efficiency, ubiquitous coverage, and enhanced Quality of Service (QoS) support. Current LTE system downlink (DL) and uplink (UL) link budgets are designed for coverage of high-end devices (such as the most advanced smartphones and tablets) that can support relatively high DL and UL link budgets.

[0061] However, it is also desirable to support low-cost, low-rate devices. For example, certain standards (e.g., LTE Release 12) have introduced new UEs (referred to as Category 0 UEs) that are typically designed for low-cost or machine-type communications. For machine-type communications (MTC), various requirements may be relaxed because only a limited amount of information may need to be exchanged. For example, the maximum bandwidth may be reduced (relative to legacy UEs), a single receive radio frequency (RF) chain may be used, the peak rate may be reduced (e.g., the transport block size may be a maximum of 100 bits), the transmit power may be reduced, rank 1 transmission may be used, and half-duplex operation may be performed.

[0062] In some cases, if half-duplex operation is performed, the MTC UE may have a relaxed switching time from transmission to reception (or vice versa). For example, the switching time may be relaxed from 20 μs for conventional UEs to 1 ms for MTC UEs. Release 12 MTC UEs may still monitor downlink (DL) control channels in the same manner as conventional UEs, for example, monitoring wideband control channels (e.g., PDCCH) in the first few symbols and narrowband control channels (e.g., ePDCCH) that occupy a relatively narrowband but span the length of a subframe.

[0063] Certain standards (e.g., LTE Release 13) may introduce support for various additional MTC enhancements, referred to herein as enhanced MTC (or eMTC). For example, eMTC may provide up to 15 dB of coverage enhancement to MTC UEs, which may be achieved, for example, through transmission time interval (TTI) bundling of various channels (e.g., PDSCH, PUSCH, PRACH, and / or MPDCCH).

[0064] like Figure 5 As illustrated in the subframe structure 500 of FIG. 5 , an eMTC UE may support narrowband operation while operating in a wider system bandwidth (eg, 1.4 / 3 / 5 / 10 / 15 / 20 MHz). Figure 5 In the example illustrated in , the conventional legacy control region 510 may span the system bandwidth for the first few symbols, while a narrowband region 530 of the system bandwidth (spanning a narrow portion of the data region 520) may be reserved for an MTC physical downlink control channel (referred to herein as mPDCCH) and for an MTC physical downlink shared channel (referred to herein as mPDSCH). In some cases, an MTC UE monitoring the narrowband region may operate at 1.4 MHz or 6 resource blocks (RBs) and may use a demodulation reference signal (DM-RS) for demodulation.

[0065] However, as mentioned above, eMTC UEs may be able to operate in cells with bandwidths greater than 6 RBs. Within this larger bandwidth, each eMTC UE may still operate (e.g., monitor / receive / transmit) while complying with the 6 physical resource block (PRB) constraint. In some cases, different eMTC UEs may be served by different narrowband regions (e.g., each narrowband region spans 6 PRB blocks).

[0066] In Release 11, an enhanced physical downlink control channel (ePDCCH) was introduced. In contrast to the PDCCH, which spans the first few symbols in a subframe, the ePDCCH is based on frequency division multiplexing (FDM) and spans the entire subframe (of symbols). In addition, the ePDCCH can only support DM-RS, compared to the conventional PDCCH CRS support.

[0067] In some cases, ePDCCH can be configured differently for each UE. For example, each UE in the network can be configured to monitor a different set of resources to find an ePDCCH directed to that UE. In addition, ePDCCH supports two modes of operation: localized ePDCCH, where a single precoder is applied to each PRB; and distributed ePDCCH, where two precoders cycle through the allocated resources within each PRB pair.

[0068] The ePDCCH can be constructed based on enhanced resource element groups (eREGs) and enhanced control channel elements (eCCEs). In general, eREGs are defined by excluding DM-RS REs (assuming a maximum amount of DM-RS (e.g., 24 DM-RS REs in a subframe using a normal cyclic prefix and 16 DM-RS REs in a subframe using an extended cyclic prefix)) and including any non-DM-RS REs (REs that do not carry DM-RS). Thus, in a subframe using a normal cyclic prefix, the number of eREGs available for ePDCCH is 144 (12 subcarriers x 14 symbols - 24 DM-RS = 144 REs), while for an extended cyclic prefix, the number of REs available for ePDCCH is 128 (12 subcarriers x 12 symbols - 16 DM-RS = 128 REs).

[0069] In some cases, a PRB pair is divided into 16 eREGs, regardless of the subframe type, cyclic prefix type, PRB pair index, subframe index, etc. Thus, in a subframe using a normal cyclic prefix, there are 9 REs per eREG, and in a subframe using an extended cyclic prefix, there are 8 REs per eREG. In some cases, the eREG to RE mapping may follow a cyclic / sequential and frequency first time second approach, which may be beneficial for equalizing the number of available REs per eREG. In addition, due to the presence of other signals, the number of REs available for ePDCCH may not be fixed and may be different for different eREGs in a PRB pair.

[0070] As mentioned above, MTC and / or eMTC operations may be supported in a wireless communication network (e.g., co-existing with LTE or some other RAT). Fig. 6A and 6B An example of how MTC UEs in MTC operation may co-exist within a broadband system such as LTE is illustrated.

[0071] like Fig. 6A As illustrated in the example frame structure of , subframes 610 associated with MTC and / or eMTC operations may be time division multiplexed (TDM) with regular subframes 620 associated with LTE (or some other RAT).

[0072] Additionally or alternatively, such as Figure 6BAs illustrated in the example frame structure of , one or more narrowbands 650 used by MTC UEs in MTC can be frequency-division multiplexed (FDM) within a wider bandwidth 660 supported by LTE. Multiple narrowband areas can be supported for MTC and / or eMTC operations, wherein each narrowband area spans a bandwidth of no more than 6 RBs in total. In some cases, each MTC UE in MTC operation can operate in one narrowband area (e.g., at 1.4MHz or 6 RBs) at a time. However, at any given time, the MTC UE in MTC operation can be retuned to other narrowband areas in the wider system bandwidth. In some examples, multiple MTC UEs can be served by the same narrowband area. In other examples, multiple MTC UEs can be served by different narrowband areas (e.g., each narrowband area spans 6 RBs, or as mentioned above, a smaller number of RBs). In yet other examples, different combinations of MTC UEs can be served by one or more of the same narrowband areas and / or one or more different narrowband areas.

[0073] MTC UEs can operate in the narrowband region for various operations (e.g., monitoring / receiving / transmitting). Figure 6B As shown in , a first narrowband region of a subframe (e.g., spanning no more than 6 RBs of wideband data) may be monitored by one or more MTC UEs to look for PSS, SSS, PBCH, MTC signaling, or paging transmissions from a BS in a wireless communication network. Figure 6B As shown in , the second narrowband region of the subframe (e.g., also spanning no more than 6 RBs of wideband data) may be used by the MTC UE to transmit RACH or data previously configured in signaling received from the BS. In some cases, the second narrowband region may be utilized by the same MTC UE that utilizes the first narrowband region (e.g., the MTC UE may have retuned to the second narrowband region for transmission after monitoring in the first narrowband region). In some cases (although not shown), the second narrowband region may be utilized by a different MTC UE than the MTC UE that utilizes the first narrowband region.

[0074] Although the examples described herein assume a narrowband of 6 RBs, those skilled in the art will recognize that the techniques presented herein may also be applied to narrowband regions of different sizes (eg, 1 RB, etc.).

[0075] Example machine type communication operations utilizing shared RF spectrum

[0076] As mentioned above, devices operating in SRFS perform LBT. An MTC UE may not be able to simultaneously receive on multiple narrowband areas of the SRFS band. Such an MTC UE should detect transmissions occupying a wideband (e.g., 20 MHz wideband) area of ​​the SRFS band while receiving from one narrowband area of ​​the wideband area. The amount of energy in the narrowband area is less than the total transmission energy spread over the entire wideband area. According to aspects of the present disclosure, a technique is provided for an MTC UE to perform energy detection on a narrowband area of ​​the SRFS band as part of CCA.

[0077] As previously mentioned, MTC devices may transmit and receive bundled transmissions for coverage enhancement and other reasons. Previously used LBT techniques (e.g., IEEE 802.11 CCA) may not receive for a sufficiently long period of time to determine that the frequency band will not be used by another device over the entire length of the bundled transmission. According to aspects of the present disclosure, techniques are provided for a BS or UE performing MTC operations to perform CCA over a longer period of time to accommodate the duration of the bundled transmission.

[0078] According to aspects of the present disclosure, a BS (e.g., an eNB) acting as a controller of a cellular cell supporting MTC UEs may perform CCA or enhanced CCA (eCCA) on an SRFS band and subsequently transmit a Wi-Fi (e.g., IEEE 802.11ax) preamble that reserves the SRFS band for a period of time equal to the sum of the time for the BS to transmit transmission resource assignments to one or more UEs and the time for the UEs to follow these assignments (e.g., by transmitting or receiving according to these assignments). These assignments may be communicated via one or more PDCCHs and / or ePDCCHs that may be bundled. Bundling (e.g., of transmissions made by the BS and transmissions made by the UEs) may be accounted for when the BS calculates the period of time to reserve the SRFS band. These assignments may be for one or more MTC UEs to transmit or receive bundled and / or non-bundled transmissions on a narrowband region of the SRFS band. These MTC UEs may follow the one or more assignments without performing CCA because the Wi-Fi preamble transmitted by the BS reserves the SRFS band for the duration that these MTC UEs operate.

[0079] According to aspects of the present disclosure, the preamble transmitted by the BS may be a broadband (e.g., 20 MHz wideband) preamble. The broadband preamble may be detectable by both MTC UE and non-MTC UE. The broadband preamble may be decodable by a device (e.g., non-MTC UE and BS) that can receive broadband signals and may reserve a broadband region of the SRFS band for a period of time.

[0080] According to various aspects of the present disclosure, a BS may transmit a narrowband preamble on a narrowband region of an SRFS band after transmitting a wideband preamble. The wideband preamble may be decodable by a device that can receive a wideband signal (e.g., a non-MTC UE and a BS) and reserve a wideband region of the SRFS band for a period of time. The narrowband preamble may be decodable by both a device that can receive a wideband signal and a device that cannot receive a wideband signal (e.g., an MTC UE). The narrowband preamble may reserve a narrowband region of the SRFS band for a period of time. A device that decodes either a wideband preamble or a narrowband preamble may refrain from transmitting on the reserved region (either wideband or narrowband) for the period of time indicated by these preambles.

[0081] According to various aspects of the present disclosure, a device (e.g., a BS, a non-MTC UE, or an MTC UE) may perform a CCA before transmitting a bundled transmission on a narrowband region of an SRFS band, and may calculate a duration for the CCA based on the duration of the bundled transmission. The duration of the bundled transmission may be calculated as the number of transmission time intervals (TTIs) used to transmit the bundled transmission. The calculated duration for the CCA may be only a fraction (e.g., 1 / 20) of the duration of the bundled transmission. For example, the BS may determine to transmit a bundled PDCCH on a narrowband region of the SRFS band over eight TTIs (e.g., milliseconds). In this example, the BS may calculate the duration of the CCA to be performed before starting the transmission of the bundled PDCCH as 8 / 20 of the TTI.

[0082] According to various aspects of the present disclosure, a BS may transmit an indication of a downlink transmission on a narrowband region of an SRFS band before transmitting a downlink transmission. That is, the BS may transmit an indication of a downlink transmission to be transmitted on the narrowband region on a narrowband region. The BS may transmit the indication before performing CCA for the indicated downlink transmission. The indication may be, for example, an M sequence, a Chu sequence, or a downlink channel use beacon signal (D-CUBS). A UE receiving the indication may keep the UE's receiver powered on and active for a duration exceeding the calculated duration of the CCA to be performed by the BS. The UE may start searching for the indicated DL signal at the end of the calculated duration of the CCA. If the UE starts receiving a signal from the BS before the end of the duration, the UE may continue to power on the receiver and be active at least until the UE has received a DL transmission. For example, a UE may operate in a coverage enhancement state, in which transmissions from the UE's serving BS are bundled over four TTIs. In this example, the serving BS may transmit a Chu sequence in a narrowband region of the SRFS band to indicate that the serving BS will transmit a DL signal to the UE. Still in this example, the UE decodes the Chu sequence and calculates that the CCA performed by the BS will have a duration of 4 / 20 of the TTI. Still in this example, the UE determines to activate the UE's receiver and start searching for DL ​​signals from the BS after 4 / 20 of the TTI after receiving the Chu sequence. The indication may be transmitted in a narrowband that the UE is expected to monitor, for example, a narrowband PCFICH. The narrowband PCFICH signal may further indicate downlink and uplink channel splitting, PLMN information, and / or other information.

[0083] According to various aspects of the present disclosure, a BS may provide an indication of one or more TTIs to be used by a UE to transmit a random access channel (RACH) signal to the BS over a narrowband region of an SRFS frequency band. A UE receiving the indication may determine to delay transmitting a RACH signal to the BS over the narrowband region until the indicated TTI.

[0084] According to various aspects of the present disclosure, a UE may transmit a channel state indicator (CSI) feedback to a BS over a narrowband region of an SRFS band. For non-periodic CSI feedback to a BS, the BS may trigger the UE to provide non-periodic CSI feedback about a narrowband region by requesting CSI feedback in a grant transmitted to the UE. The BS may reserve a wideband region including a narrowband region or only the narrowband region by transmitting a preamble, as described above. The UE may transmit non-periodic CSI feedback over a narrowband region according to a grant received from the BS without performing CCA. For periodic CSI feedback, the BS may indicate a periodic opportunity window for the UE to transmit periodic CSI feedback over a narrowband region of an SRFS band. The UE may perform CCA on the narrowband region before transmitting a periodic CSI feedback report to the BS over the narrowband region of the SRFS band.

[0085] According to aspects of the present disclosure, a BS (eg, eNB) acting as a controller of a cell supporting MTC UEs may perform CCA or enhanced CCA (eCCA) on the SRFS frequency band before transmitting to the MTC UEs on a narrowband region of the SRFS frequency band.

[0086] According to aspects of the present disclosure, an MTC UE may perform CCA or eCCA on a narrowband region of the SRFS band before transmitting on the narrowband region of the SRFS band. The UE that performs CCA or eCCA on the narrowband region of the SRFS band may calculate a threshold energy level to be used in the CCA or eCCA based on the size of the narrowband region and the size of the broadband region including the narrowband region. For example, if the UE is performing CCA for a 1.08 MHz (e.g., 6 RBs) narrowband region included in a 20 MHz (e.g., 110 RBs) broadband region, the UE may calculate a threshold energy level for the CCA that is different from a threshold energy level for the 20 MHz channel. In this example, the UE may determine (e.g., by looking up in a table) a threshold energy level of -62 dBm for the 20 MHz channel. Still in this example, the UE may calculate a threshold energy level for the CCA by using the following formula:

[0087] E CCA,NB =E CCA,WB –10 log 10 (WB / NB) (1),

[0088] Where E CCA,NB is the threshold energy level for narrowband CCA,

[0089] E CCA,WB is the threshold energy level for wideband CCA,

[0090] WB is the bandwidth of the broadband region, and

[0091] NB is the bandwidth of the narrowband region.

[0092] Still in this example, the UE may calculate the threshold energy level for the CCA as -75dBm = -62dBm - 10log 10 (20MHz / 1.08MHz).

[0093] Figure 7 1 illustrates example operations 700 for wireless communications by a base station (BS) using a shared radio frequency spectrum (SRFS) band in accordance with certain aspects of the present disclosure described above. Operations 700 may be performed by a BS such as Figure 1 The eNB 110a shown in FIG. 1 is used for execution.

[0094] Operations 700 begin at 702 by performing a channel clearness assessment (CCA) for at least a portion of the SRFS including one or more narrowband areas. Operations continue at 704 by the BS communicating with at least one machine type communication (MTC) user equipment (UE) on at least one of the narrowband areas after performing the CCA.

[0095] Figure 8 Example operations 800 are illustrated for wireless communications by a machine type communication (MTC) user equipment (UE) using a shared radio frequency spectrum (SRFS) band in accordance with certain aspects of the present disclosure described above. Operations 800 may be performed by an MTC UE, such as a Figure 1 120d) shown in FIG.

[0096] Operations 800 begin at 802 with an MTC UE receiving a resource assignment in a narrowband region of an SRFS frequency band from a base station (BS) for the MTC UE to use for communicating with the BS. Operations continue at 804 with the MTC UE communicating with the BS over the narrowband region without performing a clear channel assessment (CCA) for the narrowband region.

[0097] Fig. 9 Example operations 900 are illustrated for wireless communications by a machine type communication (MTC) user equipment (UE) using a shared radio frequency spectrum (SRFS) band in accordance with certain aspects of the present disclosure described above. Operations 900 may be performed by an MTC UE, such as a Figure 1 120d) shown in FIG.

[0098] Operations 900 begin at 902 with the MTC UE performing a clear channel assessment (CCA) for a narrowband region of the SRFS frequency band. Operations continue at 904 with the MTC UE communicating with a base station (BS) over the narrowband region.

[0099] In the current (e.g., Release 12) LTE wireless communication protocol, a BS (e.g., Figure 1 The eNB 110a shown in FIG. 110a ) may transmit a discovery reference signal (DRS). The DRS may include the previously mentioned PSS, SSS, CRS, and CSI-RS. The discovery reference signal may permit UEs served in neighboring cells to measure the strength of signals (e.g., DRS), which the UEs may use to determine whether to reselect to a cell served by the BS. The UE may be configured (e.g., by the UE's serving BS) with a bandwidth in which the UE measures the DRS. For example, the UE may be configured to measure the DRS in the bandwidth of a neighboring cell to determine whether the UE should reselect to the neighboring cell. The bandwidth configured for the UE may be 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz.

[0100] According to aspects of the present disclosure, a BS may configure a narrowband DRS and transmit the narrowband DRS in one or more narrowband regions of a wider system bandwidth. The narrowband DRS may be transmitted in the same frequency band as a normal (non-narrowband) DRS or in a different frequency band. The narrowband DRS may use a different periodicity and / or subframe offset than a normal DRS. For example and with reference to Figure 3 , the BS may transmit normal PSS and normal SSS in symbols 6 and 5 of subframes 0 and 5 of each frame, respectively. Still in this example, the BS may configure and transmit narrowband PSS and narrowband SSS in symbols 9 and 8 of subframes 2 and 7 of each frame, respectively. Still in this example and referring to Figure 5 , normal PSS and normal SSS can be transmitted in the center 6 RBs of the wider system bandwidth, while narrowband PSS and narrowband SSS can be transmitted in the narrowband region 530.

[0101] According to various aspects of the present disclosure, a UE (e.g., an MTC UE) may be configured (e.g., by a serving BS of the UE) to search for and / or measure a narrowband DRS in a narrowband region of a wider system bandwidth. The narrowband region may be, for example, a Rel-13eMTC narrowband having a bandwidth of 1.08 MHz (e.g., six RBs) or a Rel-13 NB-IOT narrowband having a bandwidth of 180 kHz (e.g., one RB). The UE may measure the narrowband DRS and report the measurement to the serving BS. For example and with reference to Figure 5 , the MTC UE may be configured to measure the narrowband CRS in the narrowband area 530 and report the measurement to the serving BS of the UE.

[0102] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to cover: a, b, c, ab, ac, bc, and abc.

[0103] The various operations of the methods described above may be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Software should be broadly interpreted to mean instructions, data, code, or any combination thereof, whether referred to as software, firmware, middleware, code, microcode, hardware description language, machine language, or other. In general, where operations are illustrated in the accompanying drawings, those operations may be performed by any suitable corresponding device plus functional components.

[0104] For example, a means for performing may include one or more controllers or processors, such as Figure 2 The receiving processor 258 and / or the controller / processor 280 of the user terminal 120 illustrated in Figure 2 1 and / or the controller / processor 240 of the base station 110 illustrated in FIG. Means for receiving and / or means for communicating may include, for example, Figure 2 The receive processor 258 and / or antenna(s) 252 of the user terminal 120 illustrated in Figure 2 The transmit processor 220 and / or the antenna(s) 234 of the eNB 110 illustrated in FIG. The means for transmitting and / or the means for sending may include, for example Figure 2 The transmit processor 220 and / or antenna(s) 234 of the eNB illustrated in FIG. The means for determining may include, for example Figure 2 The controller / processor 280 and memory 282 of the user terminal 120 illustrated in Figure 2 Controller processor 240 and memory 242 of base station 110 illustrated in FIG.

[0105] 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, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or a combination thereof.

[0106] The skilled person will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the disclosure herein may be implemented as hardware, software, or a combination thereof. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The skilled person may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0107] The various illustrative logical blocks, modules, and circuits described in conjunction with the disclosure herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0108] The steps of the method or algorithm described in conjunction with the disclosure herein can be implemented directly in hardware, in a software module executed by a processor, or in a combination thereof. The software module can reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a phase change memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read / write information from / to the storage medium. In an alternative, the storage medium can be integrated into the processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In an alternative, the processor and the storage medium can reside in a user terminal as discrete components.

[0109] In one or more exemplary designs, the functions described can be implemented in hardware, software, or a combination thereof. If implemented in software, each function can be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any media that facilitates the transfer of a computer program from one place to another. Storage media can be any available media that can be accessed by a general or special-purpose computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD / DVD or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code means in the form of instructions or data structures and can be accessed by a general or special-purpose computer, or a general or special-purpose processor. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0110] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the universal principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Therefore, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication by a user equipment (UE) using a shared radio frequency spectrum (SRFS) band, the UE supporting narrowband operation, the method comprising: receiving a resource assignment in a narrowband region reserved for a period of time in the SRFS frequency band from a base station (BS) via a preamble transmission; as well as Communicating with the BS over the narrowband area during at least a portion of the time period without performing a clear channel assessment (CCA) on the narrowband area.

2. The method of claim 1, wherein: Communicating with the BS includes transmitting an uplink transmission to the BS.

3. The method of claim 1, wherein: Communicating with the BS includes receiving a downlink transmission from the BS; and the method further includes receiving an indication of the downlink transmission in the narrowband region prior to receiving the downlink transmission.

4. The method of claim 3, wherein the indication comprises at least one of an M sequence, a Chu sequence, or a downlink channel usage beacon signal (D-CUBS).

5. The method of claim 1, wherein: Communicating with the BS includes transmitting channel state information (CSI) feedback to the BS.

6. The method of claim 1, further comprising: At least one discovery reference signal (DRS) is received over at least one of the narrowband region or another narrowband region of the SRFS frequency band.

7. The method of claim 6, further comprising: A configuration is received from the BS, wherein the configuration configures the UE to receive at least one discovery reference signal (DRS) over at least one of the narrowband region or another narrowband region of the SRFS frequency band.

8. The method of claim 1, wherein the time period corresponds to a sum of a time for the BS to transmit the resource assignment and a time for the UE to transmit or receive according to the resource assignment.

9. The method of claim 1, wherein the resource assignment is associated with a bundled transmission.

10. The method of claim 1, wherein the preamble transmission corresponds to a wideband preamble transmission, a narrowband preamble transmission, or both.

11. An apparatus for wireless communication, comprising: at least one processor; as well as a memory coupled to the at least one processor, the memory comprising instructions executable by the at least one processor to cause the apparatus to: receiving a resource assignment in a narrowband region reserved for a period of time in a shared radio frequency spectrum (SRFS) band from a base station (BS) via a preamble transmission; as well as Communicating with the BS over the narrowband area during at least a portion of the time period without performing a clear channel assessment (CCA) on the narrowband area.

12. The apparatus of claim 11, wherein the processor is configured to communicate with the BS by transmitting an uplink transmission to the BS.

13. The apparatus of claim 11, wherein the processor is configured to: communicate with the BS by receiving a downlink transmission from the BS; and receive an indication of the downlink transmission in the narrowband region before receiving the downlink transmission.

14. The apparatus of claim 13, wherein the indication comprises at least one of an M sequence, a Chu sequence, or a downlink channel usage beacon signal (D-CUBS).

15. The apparatus of claim 11, wherein the processor is configured to communicate with the BS by transmitting channel state information (CSI) feedback to the BS.

16. The apparatus of claim 11, wherein the processor is configured to receive at least one discovery reference signal (DRS) over at least one of the narrowband region or another narrowband region of the SRFS frequency band.

17. The apparatus of claim 16, wherein the processor is configured to: receive a configuration from the BS, wherein the configuration configures the apparatus to receive at least one discovery reference signal (DRS) over at least one of the narrowband region or another narrowband region of the SRFS frequency band.

18. The apparatus of claim 11, wherein the time period corresponds to a sum of time for the BS to transmit the resource assignment and time for the apparatus to transmit or receive according to the resource assignment.

19. The apparatus of claim 11, wherein the resource assignment is associated with a bundled transmission.

20. The apparatus of claim 11, wherein the preamble transmission corresponds to a wideband preamble transmission, a narrowband preamble transmission, or both.

21. A device for wireless communication, comprising: means for receiving, via a preamble transmission, from a base station (BS) a resource assignment in a narrowband region of a shared radio frequency spectrum (SRFS) band reserved for a period of time; as well as Means for communicating with the BS over the narrowband area during at least a portion of the time period without performing a clear channel assessment (CCA) on the narrowband area.

22. The apparatus of claim 21, wherein the time period corresponds to a sum of time for the BS to transmit the resource assignment and time for the device to transmit or receive according to the resource assignment.

23. The apparatus of claim 21, wherein the resource assignment is associated with a bundled transmission.

24. The apparatus of claim 21, wherein the preamble transmission corresponds to a wideband preamble transmission, a narrowband preamble transmission, or both.

25. A non-transitory computer-readable medium for wireless communications comprising instructions that, when executed by a processing system of a user equipment (UE) supporting narrowband operation, cause the UE to perform operations comprising: receiving a resource assignment in a narrowband region reserved for a period of time in a shared radio frequency spectrum (SRFS) band from a base station (BS) via a preamble transmission; as well as Communicating with the BS over the narrowband area during at least a portion of the time period without performing a clear channel assessment (CCA) on the narrowband area.

26. The non-transitory computer-readable medium of claim 25, wherein the time period corresponds to a sum of time for the BS to transmit the resource assignment and for the UE to transmit or receive according to the resource assignment.

27. The non-transitory computer readable medium of claim 25, wherein the resource assignment is associated with a bundled transmission.

28. The non-transitory computer-readable medium of claim 25, wherein the preamble transmission corresponds to a wideband preamble transmission, a narrowband preamble transmission, or both.

Images