Synchronization for standalone LTE broadcast

Abstract

Synchronization for Standalone LTE Broadcasts. Various aspects of this disclosure relate to wireless communications, and more particularly to synchronization for standalone LTE broadcasts. In one aspect, a method is provided that can be performed by a wireless device such as a base station (BS). The method generally includes: providing unicast coverage to one or more user equipment (UEs) in a unicast coverage area within a larger coverage area; transmitting unicast data in one or more subframes; and transmitting a synchronization signal within one or more broadcast subframes, wherein the broadcast signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area.

Description

[0001] This application is a divisional application of the patent application filed on April 5, 2017, with international application number PCT / US2017 / 026191, Chinese application number 201780022592.9, and entitled "Synchronization for Independent LTE Broadcast".

[0002] Priority claim according to 35 USC §119

[0003] This application claims priority to U.S. Application No. 15 / 479,210, filed April 4, 2017, which claims the benefit of U.S. Provisional Patent Applications S / N. 62 / 320,953 and 62 / 336,353, filed April 11, 2016 and May 13, 2016, respectively, the entire contents of which are incorporated herein by reference.

[0004] open field

[0005] Certain aspects of this disclosure generally relate to wireless communications, and in particular to synchronization for independent LTE broadcasting.

[0006] background

[0007] Wireless communication systems are widely deployed to provide various types of communication content, such as voice and data. These systems can 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, 3GPP Long Term Evolution (LTE) / LTE-Advanced systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.

[0008] Generally, a wireless multiple access communication system can support communication from multiple wireless terminals simultaneously. Each terminal communicates with one or more base stations via forward and reverse links. The forward link (or downlink) is the communication link from the base station to the terminal, while the reverse link (or uplink) is 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] The wireless communication network may include several base stations capable of supporting communication between several wireless devices. Wireless devices may include user equipment (UE). Machine-type communication (MTC) can refer to communication involving at least one remote device at at least one end of the communication, and may include forms of data communication involving one or more entities that do not necessarily require human interaction. An MTC UE may include a UE capable of MTC communication with an MTC server and / or other MTC devices via, for example, a Public Land Mobile Network (PLMN).

[0010] Overview

[0011] The systems, methods, and apparatus of this disclosure each have several aspects, and their desired properties are not solely attributed to any single aspect. Without limiting the scope of this disclosure as set forth in the appended claims, some features will now be briefly discussed. Upon consideration of this discussion, and especially after reading the section entitled "Detailed Description," it will be understood how the features of this disclosure provide advantages including improved communication between access points and stations in a wireless network.

[0012] Certain aspects of this disclosure provide a wireless communication method performed by a wireless node, such as a base station (BS). The method generally includes: providing unicast coverage to one or more user equipment (UEs) in a unicast coverage area within a larger coverage area; transmitting unicast data in one or more subframes; and transmitting a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area.

[0013] Certain aspects of this disclosure provide an apparatus for wireless communication. The apparatus generally includes at least one processor configured to: provide unicast coverage to one or more user equipment (UEs) in a unicast coverage area within a larger coverage area; transmit unicast data in one or more subframes; and transmit a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area. The apparatus generally also includes a memory coupled to the at least one processor.

[0014] Certain aspects of this disclosure provide an apparatus for wireless communication. The apparatus generally includes: means for providing unicast coverage to one or more user equipment (UEs) in a unicast coverage area within a larger coverage area; means for transmitting unicast data in one or more subframes; and means for transmitting a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area.

[0015] Certain aspects of this disclosure provide a non-transient computer-readable medium for wireless communication. The non-transient computer-readable medium generally includes instructions that, when executed by at least one processor, configure the at least one processor to: provide unicast coverage to one or more user equipment (UEs) in a unicast coverage area within a larger coverage area; transmit unicast data in one or more subframes; and transmit a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area.

[0016] Certain aspects of this disclosure provide a method for wireless communication performed by a wireless node (such as a base station (BS)). The method generally includes: transmitting a synchronization signal of a first type within anchor frames that occur periodically in a first periodic manner; providing indications of one or more unicast subframes scheduled to occur between anchor frames; providing indications of one or more broadcast subframes scheduled to occur between anchor frames; and transmitting a plurality of different system information blocks (SIBs) in at least one of the first anchor frame of the anchor frame or the first unicast subframe of the one or more unicast subframes.

[0017] Certain aspects of this disclosure provide an apparatus for wireless communication. The apparatus generally includes at least one processor configured to: transmit a synchronization signal of a first type within anchor frames occurring at a first periodicity; provide indications of one or more unicast subframes scheduled to occur between anchor frames; provide indications of one or more broadcast subframes scheduled to occur between anchor frames; and transmit a plurality of different system information blocks (SIBs) in at least one of a first anchor frame of an anchor frame or a first unicast subframe of one or more unicast subframes. The apparatus generally also includes a memory coupled to the at least one processor.

[0018] This disclosure provides an apparatus for wireless communication. The apparatus generally includes: means for transmitting a synchronization signal of a first type within anchor frames that occur periodically in a first periodic manner; means for providing an indication of one or more unicast subframes scheduled to occur between anchor frames; means for providing an indication of one or more broadcast subframes scheduled to occur between anchor frames; and means for transmitting a plurality of different system information blocks (SIBs) in at least one of a first anchor frame of an anchor frame or a first unicast subframe of one or more unicast subframes.

[0019] Certain aspects of this disclosure provide a non-transient computer-readable medium for wireless communication. The non-transient computer-readable medium generally includes instructions that, when executed by at least one processor, configure the at least one processor to: transmit a synchronization signal of a first type within anchor frames that occur at a first periodicity; provide indications of one or more unicast subframes scheduled to occur between anchor frames; provide indications of one or more broadcast subframes scheduled to occur between anchor frames; and transmit a plurality of different system information blocks (SIBs) in at least one of a first anchor frame of an anchor frame or a first unicast subframe of one or more unicast subframes.

[0020] Certain aspects of this disclosure provide a method for wireless communication performed by a wireless node, such as a user equipment (UE). The method generally includes: monitoring a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage over a larger coverage area; performing acquisition based on the synchronization signal; and monitoring unicast data within the one or more subframes.

[0021] Certain aspects of this disclosure provide an apparatus for wireless communication. The apparatus generally includes at least one processor configured to: monitor a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage over a larger coverage area; perform acquisition based on the synchronization signal; and monitor unicast data within the one or more subframes. The apparatus generally also includes a memory coupled to the at least one processor.

[0022] Certain aspects of this disclosure provide an apparatus for wireless communication. The apparatus generally includes: means for monitoring a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage over a larger coverage area; means for performing acquisition based on the synchronization signal; and means for monitoring unicast data within the one or more subframes.

[0023] Certain aspects of this disclosure provide a non-transient computer-readable medium for wireless communication. The non-transient computer-readable medium generally includes instructions that, when executed by at least one processor, configure the at least one processor to: monitor a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage over a larger coverage area; perform acquisition based on the synchronization signal; and monitor unicast data in one or more subframes.

[0024] Certain aspects of this disclosure provide a method for wireless communication performed by a wireless node (such as a user equipment (UE)). The method generally includes: monitoring a synchronization signal of a first type within an anchor subframe that occurs periodically in a first periodic manner; obtaining an indication of one or more unicast subframes scheduled to occur between anchor frames; obtaining an indication of one or more broadcast subframes scheduled to occur between anchor frames; and obtaining a plurality of distinct system information blocks (SIBs) in at least one of the first anchor frame or the first unicast subframe of the one or more unicast subframes.

[0025] Certain aspects of this disclosure provide an apparatus for wireless communication. The apparatus generally includes at least one processor configured to: monitor a synchronization signal of a first type within anchor frames that occur periodically in a first periodic manner; obtain indications of one or more unicast subframes scheduled to occur between anchor frames; obtain indications of one or more broadcast subframes scheduled to occur between anchor frames; and obtain a plurality of distinct system information blocks (SIBs) in at least one of the first anchor frame or the first unicast subframe of the one or more unicast subframes. The apparatus generally also includes a memory coupled to the at least one processor.

[0026] This disclosure provides an apparatus for wireless communication. The apparatus generally includes: means for monitoring a first type of synchronization signal within an anchor frame that occurs periodically in a first periodic manner; means for obtaining an indication of one or more unicast subframes scheduled to occur between anchor frames; means for obtaining an indication of one or more broadcast subframes scheduled to occur between anchor frames; and means for obtaining a plurality of different system information blocks (SIBs) in at least one of the first anchor frame or the first unicast subframe of one or more unicast subframes.

[0027] Certain aspects of this disclosure provide a non-transient computer-readable medium for wireless communication. The non-transient computer-readable medium generally includes instructions that, when executed by at least one processor, configure the at least one processor to: monitor a synchronization signal of a first type within an anchor frame that occurs periodically in a first periodic manner; obtain an indication of one or more unicast subframes scheduled to occur between anchor frames; obtain an indication of one or more broadcast subframes scheduled to occur between anchor frames; and obtain a plurality of different system information blocks (SIBs) in at least one of the first anchor frame or the first unicast subframe of the one or more unicast subframes.

[0028] Other aspects, features, and embodiments of the invention will become apparent to those skilled in the art after reading the following description of specific exemplary aspects of the invention in conjunction with the accompanying drawings. Although features of this disclosure may be discussed hereinafter with respect to certain aspects and drawings, all embodiments of this disclosure may include one or more of the advantageous features discussed herein. In other words, while one or more aspects may be discussed having certain advantageous features, one or more such features may also be used according to various aspects of this disclosure discussed herein. Similarly, although exemplary aspects may be discussed hereinafter as aspects of an apparatus, system, or method, it should be understood that such exemplary aspects may be implemented in various apparatuses, systems, and methods. Brief description of the attached diagram

[0030] To gain a more detailed understanding of the manner in which the features described above are presented in this disclosure, reference can be made to various aspects of the above brief overview, some of which are illustrated in the accompanying drawings. However, the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as other equivalent aspects are permissible in this description.

[0031] Figure 1 It is a block diagram that conceptually illustrates an example of a wireless communication network according to certain aspects of this disclosure.

[0032] Figure 2 A block diagram is shown that illustrates a conceptual example of a base station and a user equipment (UE) communicating in a wireless communication network according to certain aspects of this disclosure.

[0033] Figure 3 It is a block diagram that conceptually illustrates an example of a frame structure in a wireless communication network according to certain aspects of this disclosure.

[0034] Figure 4 It is a block diagram that conceptually explains two exemplary subframe formats with a normal cyclic prefix.

[0035] Figure 5 Various components that can be used in wireless devices according to certain aspects of this disclosure are explained.

[0036] Figure 6 This is a flowchart illustrating an example operation of wireless communication by a base station (BS) according to certain aspects of this disclosure.

[0037] Figure 7 This is a flowchart illustrating example operations of wireless communication performed by a user equipment (UE) according to certain aspects of this disclosure.

[0038] Figure 8 An example timeline for LTE standalone broadcasting based on certain aspects of this disclosure is explained.

[0039] Figure 9 An example deployment scenario is described, illustrating that some of the user equipment (UE) may be unable to receive unicast synchronization signals according to certain aspects of this disclosure.

[0040] Figure 10 This is a flowchart illustrating an example operation of wireless communication by a base station (BS) according to certain aspects of this disclosure.

[0041] Figure 11 This is a flowchart illustrating example operations of wireless communication performed by a user equipment (UE) according to certain aspects of this disclosure.

[0042] Figure 12 The use of the broadcast MBSFN portion of a transmission frame for transmitting synchronization signals, according to certain aspects of this disclosure, is explained.

[0043] Figure 13 This is a flowchart illustrating an example operation of wireless communication by a base station (BS) according to certain aspects of this disclosure.

[0044] Figure 14 This is a flowchart illustrating example operations of wireless communication performed by a user equipment (UE) according to certain aspects of this disclosure.

[0045] To facilitate understanding, the same reference numerals are used where possible to designate common elements across the figures. Elements disclosed in one embodiment are contemplated for use in other embodiments without specific reference.

[0046] Detailed description

[0047] Certain aspects of this disclosure generally relate to wireless communications, and in particular to synchronization for independent LTE broadcasting.

[0048] The technologies described herein can be used in various wireless communication networks, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and others. The terms “network” and “system” are often used interchangeably. CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA), Time Division Synchronous CDMA (TD-SCDMA), and other variants of CDMA. cdma2000 encompasses the IS-2000, IS-95, and IS-856 standards. TDMA networks can implement radio technologies such as the Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and others. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). Frequency Division Duplex (FDD) and Time Division Duplex (TDD) technologies, specifically 3GPP Long Term Evolution (LTE) and LTE-A Advanced (LTE-A), are newer versions of UMTS using E-UTRA, employing 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 called the 3rd Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). The technologies described herein can be used with the aforementioned wireless networks and radio technologies, as well as other wireless networks and radio technologies. For clarity, certain aspects of these technologies are described below in reference to LTE / LTE-A Advanced, and the term LTE / LTE-A Advanced is used in most of the following description. LTE and LTE-A are generally referred to as LTE.

[0049] Examples of UEs may include cellular phones, smartphones, personal digital assistants (PDAs), wireless modems, handheld devices, tablets, laptops, netbooks, smartbooks, ultrabooks, medical devices or equipment, biometric sensors / devices, wearable devices (smartwatches, smart clothing, smart glasses, smart wristbands, smart jewelry (e.g., smart rings, smart necklaces)), entertainment devices (e.g., music or video devices, or satellite radios), vehicle components or sensors, smart meters / sensors, industrial manufacturing equipment, GPS devices, or any other suitable device configured to communicate via wireless or wired media. Some UEs may be considered evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices such as sensors, meters, monitors, location tags, etc., which can communicate with a base station, another device (e.g., a remote device), or some other entity. Wireless nodes may provide connectivity to or to a network (e.g., a wide area network, such as the Internet or cellular networks) via wired or wireless communication links.

[0050] It should be noted that although the aspects herein may be described using terms commonly associated with 3G and / or 4G wireless technologies, the aspects of this disclosure may be applied in communication systems based on other generations, such as 5G and later.

[0051] Example wireless communication network

[0052] Figure 1 An example wireless communication network 100 in which various aspects of this disclosure can be practiced is explained. The techniques presented herein can be used for synchronization in standalone LTE broadcast systems.

[0053] Wireless communication network 100 may be an LTE network or some other wireless network. Wireless communication network 100 may include several evolved B-nodes (eNBs) 110 and other network entities. An eNB is an entity that communicates with user equipment (UE) and may also be referred to as a base station, B-node, access point, etc. Each eNB can provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to the coverage area of ​​an eNB and / or the eNB subsystem serving that coverage area, depending on the context in which the term is used.

[0054] An eNB can provide communication coverage for macrocells, picocells, femtocells, and / or other types of cells. Macrocells can cover relatively large geographic areas (e.g., radius of several kilometers) and allow unrestricted access by UEs with service subscriptions. Picocells can cover relatively small geographic areas and allow unrestricted access by UEs with service subscriptions. Femtocells can cover relatively small geographic areas (e.g., residential areas) and allow restricted access by UEs associated with that femtocell (e.g., UEs in a Closed Subscriber Group (CSG)). An eNB used for macrocells may be referred to as a macro eNB. An eNB used for picocells may be referred to as a pico eNB. An eNB used for femtocells may be referred to as a femto eNB or a home eNB (HeNB). Figure 1 In the example shown, eNB 110a can be a macro eNB for macro cell 102a, eNB 110b can be a pico eNB for pico cell 102b, and eNB 110c can be a femto eNB for femto cell 102c. An eNB can support one or more (e.g., three) cells. The terms “eNB,” “base station,” and “cell” are used interchangeably herein.

[0055] The wireless communication network 100 may also include relay stations. A relay station is an entity capable of receiving data transmissions from an upstream station (e.g., an eNB or a UE) and transmitting those data to a downstream station (e.g., a UE or an eNB). A relay station can also be a UE capable of relaying transmissions for other UEs. Figure 1 In the example shown, relay station 110d can communicate with macro eNB 110a and UE 120d to facilitate communication between eNB 110a and UE 120d. A relay station may also be referred to as a relay eNB, relay base station, relay, etc.

[0056] The wireless communication network 100 can be a heterogeneous network comprising different types of eNBs (e.g., macro eNBs, pico eNBs, femto eNBs, repeater eNBs, etc.). These different types of eNBs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless communication network 100. For example, macro eNBs may have high transmit power levels (e.g., 5 to 40 watts), while pico eNBs, femto eNBs, and repeater eNBs may have lower transmit power levels (e.g., 0.1 to 2 watts).

[0057] Network controller 130 can be coupled to a group of eNBs and can provide coordination and control over these eNBs. Network controller 130 can communicate with each eNB via backhaul. These eNBs can also communicate with each other directly or indirectly, for example, via wireless or wired backhaul.

[0058] UE 120 (e.g., 120a, 120b, 120c) can be distributed throughout the wireless communication network 100, and each UE can be stationary or mobile. A UE can also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. A UE can be a cellular phone (e.g., a smartphone), personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet device, camera, gaming device, netbook, smartbook, ultrabook, etc. Figure 1 In the diagram, a solid line with a double-headed arrow indicates a desired transmission between the UE and the serving eNB, which is the eNB designated to serve the UE on the downlink and / or uplink. A dashed line with a double-headed arrow indicates a potential interference transmission between the UE and the eNB.

[0059] Figure 2 The base station / eNB 110 and UE 120 are shown (which can be...). Figure 1 A block diagram of the design of each base station / eNB and each UE. Base station 110 may be equipped with T antennas 234a to 234t, and UE 120 may be equipped with R antennas 252a to 252r, wherein generally... ,and .

[0060] At base station 110, transmit processor 220 can receive data destined for one or more UEs from data source 212, select one or more modulation and coding schemes (MCS) for each UE based on CQI received from each UE, process (e.g., encode and modulate) the data destined for each UE based on the selected MCS(s) for each UE, and provide data symbols for all UEs. Transmit processor 220 can 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. Transmit processor 220 can also generate reference symbols for reference signals (e.g., CRS) and synchronization signals (e.g., PSS and SSS). Transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols where applicable, and can provide T output symbol streams to T modulators (MODs) of demodulators / modulators 232a to 232t. Each modulator of demodulator / modulator 232 can process its own output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator of demodulator / modulator 232 can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. T downlink signals from the modulators of demodulators / modulators 232a to 232t can be transmitted via T antennas 234a to 234t respectively.

[0061] At UE 120, antennas 252a to 252r can receive downlink signals from base station 110 and / or other base stations and can provide the received signals to the demodulators (DEMODs) of demodulators / modulators 254a to 254r, respectively. Each demodulator / modulator 254 can condition (e.g., filter, amplify, down-convert, and digitize) its received signal to obtain an input sample. Each demodulator / modulator 254 can further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 can obtain the received symbols from all R demodulators / modulators 254a to 254r, perform MIMO detection on these received symbols where applicable, and provide detected symbols. The receiver processor 258 can process (e.g., demodulate and decode) these detected symbols, provide the decoded data for the UE 120 to the data trap 260, and provide the decoded control information and system information to the controller / processor 280. The channel processor can determine RSRP, RSSI, RSRQ, CQI, etc.

[0062] On the uplink, at UE 120, transmit processor 264 can receive and process data from data source 262 and control information from controller / processor 280 (e.g., reports including RSRP, RSSI, RSRQ, CQI, etc.). Transmit processor 264 can also generate reference symbols for one or more reference signals. Symbols from transmit processor 264 can be pre-encoded by TX MIMO processor 266 where applicable, further processed by modulators of demodulators / modulators 254a to 254r (e.g., for SC-FDM, OFDM, etc.), and transmitted to base station 110. At base station 110, uplink signals from UE 120 and other UEs can be received by antenna 234, processed by demodulator of demodulator / modulator 232, detected by MIMO detector 236 where applicable, and further processed by receive processor 238 to obtain decoded data and control information transmitted by UE 120. The receiver processor 238 can provide decoded data to the 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.

[0063] Controllers / processors 240 and 280 can respectively direct operations at base station 110 and UE 120 to perform the techniques described herein for defining narrowband areas for enhanced machine-type communication (eMTC) for communication between a UE (e.g., an eMTC UE) and a base station (e.g., an eNodeB). For example, processor 240 and / or other processors and modules at base station 110, and processor 280 and / or other processors and modules at UE 120 can respectively execute or direct operations at base station 110 and UE 120. For example, controllers / processors 280 and / or other controllers / processors and modules at UE 120, and controllers / processors 240 and / or other controllers / processors and modules at BS 110 can respectively execute or direct operations. Figure 6 , 7 Operations 600, 700, 1000, 1100, 1300, and 1400 are shown in 10, 11, 13, and 14. Memory 242 and 282 can store data and program code for base station 110 and UE 120, respectively. Scheduler 246 can schedule the UE for data transmission on the downlink and / or uplink.

[0064] Figure 3An exemplary frame structure 300 for FDD in LTE is shown. The transmission timeline of each of the downlink and uplink can 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 Each symbol period, for example, for a normal cyclic prefix (such as...) Figure 3 (As shown in the diagram) is 7 symbol periods, or 6 symbol periods for the extended cyclic prefix. The 2L symbol periods in each subframe can be assigned indices from 0 to 2L-1.

[0065] In LTE, an eNB can transmit the Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) on the downlink at the center of the system bandwidth used for each cell supported by that eNB. The PSS and SSS can be transmitted in subframes 0 and 5 of each radio frame with a normal cyclic prefix, respectively, in symbol periods 6 and 5, as follows: Figure 3 As shown in the diagram. The PSS and SSS can be used by the UE for cell search and acquisition. The eNB can transmit a cell-specific Reference Signal (CRS) across the system bandwidth used for each cell supported by the eNB. The 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 the Physical Broadcast Channel (PBCH) in symbol periods 0 to 3 of slot 1 in certain radio frames. The PBCH can carry some system information. The eNB can transmit other system information in certain subframes, such as System Information Blocks (SIBs) on the Physical Downlink Shared Channel (PDSCH). The eNB can transmit control information / data on the Physical Downlink Control Channel (PDCCH) for 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 for the remaining symbol periods of each subframe.

[0066] 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 may include several resource elements. Each resource element can cover one subcarrier in a symbol period and can be used to transmit a modulation symbol that can be a real or complex value.

[0067] Subframe format 410 can be used with two antennas. The CRS can be transmitted from antennas 0 and 1 during symbol periods 0, 4, 7, and 11. The reference signal is a signal known a priori to both the transmitter and receiver and may also be referred to as a pilot. The CRS is a cell-specific reference signal, for example, generated based on the cell identity (ID). Figure 4 In this configuration, for a given resource element with a marker Ra, modulated symbols can be transmitted from antenna a on that resource element, and modulated symbols may not be transmitted from other antennas on that resource element. Subframe format 420 can be used with four antennas. CRS can 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 can be transmitted on uniformly spaced subcarriers, which can be determined based on the cell ID. Depending on its cell ID, CRS can be transmitted on the same or different subcarriers. For both subframe formats 410 and 420, resource elements not used for CRS can be used to transmit data (e.g., traffic data, control data, and / or other data).

[0068] The PSS, SSS, CRS, and PBCH in LTE are described in 3GPP TS 36.211, which is publicly available, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation”.

[0069] For FDD in LTE, the interleaving structure can be used in both the downlink and uplink. For example, a Q-strand interleaving can be defined with indices 0 to Q-1, where Q can be equal to 4, 6, 8, 10, or some other value. Each interleaving may include subframes spaced Q frames apart. Specifically, interleaving q may include subframes q, q+Q, q+2Q, etc., where q∈{0, …, Q-1}.

[0070] Wireless networks can support Hybrid Automatic Repeat Request (HARQ) for data transmission on both downlink and uplink. For HARQ, a transmitter (e.g., an eNB) can send one or more transmissions of a packet until the packet is correctly decoded by a receiver (e.g., a UE) or encounters some other termination condition. For synchronous HARQ, all transmissions of the packet can be sent in single-stranded subframes. For asynchronous HARQ, each transmission of the packet can be sent in any subframe.

[0071] The UE may be located within the coverage of multiple eNBs. One of these eNBs can be selected to serve the UE. The serving eNB can be selected based on various criteria, such as received signal strength, received signal quality, path loss, etc. Received signal quality can be quantified by signal-to-noise ratio (SINR), reference signal received quality (RSRQ), or some other metric. The UE may operate in a strong interference scenario, in which the UE may observe severe interference from one or more interfering eNBs.

[0072] Evolved Multimedia Broadcast and Multicast Services (eMBMS) can be formed in a Multimedia Broadcast Single Frequency Network (MBSFN) by eNBs in a cellular cell to create an MBSFN area. An eNB can be associated with multiple MBSFN areas, for example, up to a total of eight MBSFN areas. Each eNB in ​​an MBSFN area synchronously transmits the same eMBMS control information and data.

[0073] Each area can support broadcast, multicast, and unicast services. Unicast services are services intended for a specific user, such as voice calls. Multicast services are services that can be received by a group of users, such as video subscription services. Broadcast services are services that can be received by all users, such as news broadcasts. Thus, the first MBSFN area can support a first eMBMS broadcast service (such as by providing a specific news broadcast to the UE), while the second MBSFN area can support a second eMBMS broadcast service (such as by providing a different news broadcast to a second UE).

[0074] Each MBSFN area supports multiple physical multicast channels (PMCHs) (e.g., 15 PMCHs). Each PMCH corresponds to a multicast channel (MCH). Each MCH can multiplex multiple (e.g., 29) multicast logical channels. Each MBSFN area can have one multicast control channel (MCCH). Thus, one MCH can multiplex one MCCH and multiple multicast traffic channels (MTCHs), and the remaining MCHs can multiplex multiple MTCHs. The subframes configured to carry MBSFN information can vary depending on the cell's diversity mode. Generally, MBSFNs can be carried in all subframes except those that are only available for DL ​​to the UE and special subframes. For example, when the cell is configured for FDD, MBSFNs can be configured in all subframes except 0, 4, 5, and 9. For TDD operation, MBSFNs can be configured in all subframes except 0, 1, 5, and 6.

[0075] Figure 5 The explanation can be found Figure 1The wireless communication network 100 described herein employs various components available in the wireless device 502. The wireless device 502 is an example of a device that can be configured to implement the various methods described herein. The wireless device 502 can be a base station 110 or any wireless node (e.g., 120). For example, the wireless device 502 can be configured to perform actions respectively in... Figure 6 , 7 Operations 600, 700, 1000, 1100, 1300, and 1400 (as well as other operations described herein) are shown in 10, 11, 13, and 14.

[0076] Wireless device 502 may include processor 504 that controls the operation of wireless device 502. Processor 504 may also be referred to as a central processing unit (CPU). Memory 506 (which may include read-only memory (ROM) and random access memory (RAM)) provides instructions and data to processor 504. A portion of memory 506 may also include non-volatile random access memory (NVRAM). Processor 504 typically performs logical and arithmetic operations based on program instructions stored in memory 506. Instructions in memory 506 can be executed to implement the methods described herein, such as allowing the UE to efficiently transmit data during connectionless access. Some non-limiting examples of processor 504 may include Snapdragon processors, application-specific integrated circuits (ASICs), programmable logic, and so on.

[0077] The wireless device 502 may also include a housing 508, which may include a transmitter 510 and a receiver 512 to allow data transmission and reception between the wireless device 502 and a remote location. The transmitter 510 and receiver 512 may be combined into a transceiver 514. A single transmitting antenna or multiple transmitting antennas 516 may be attached to the housing 508 and electrically coupled to the transceiver 514. The wireless device 502 may also include (not shown) multiple transmitters, multiple receivers, and multiple transceivers. The wireless device 502 may also include wireless battery charging equipment.

[0078] Wireless device 502 may also include a signal detector 518, which can be used to detect and quantize the signal level received by transceiver 514. Signal detector 518 can detect signals such as total energy, energy per symbol per subcarrier, power spectral density, and other signals. Wireless device 502 may also include a digital signal processor (DSP) 520 for processing signals.

[0079] The various components of the wireless device 502 may be coupled together by a bus system 522, which may include, in addition to a data bus, a power bus, a control signal bus, and a status signal bus. According to aspects of this disclosure discussed below, the processor 504 may be configured to access instructions stored in memory 506 to perform connectionless access.

[0080] Example synchronization for standalone LTE broadcast

[0081] In LTE, carriers are introduced for the purpose of transmitting LTE Multimedia Broadcast Multicast Service (MBMS) data. Previously, only broadcast-only LTE subframes were defined, which did not include the Physical Downlink Control Channel (PDCCH) (i.e., the control channel was removed from broadcast-only LTE subframes) and included little or no unicast traffic (i.e., all or most subframes were configured for broadcast-only). LTE MBMS carriers are independent carriers, meaning that broadcast functionality includes synchronization, channel setup, and broadcast data reception must be completed within that single MBMS carrier. That is, there is no assistance from the anchor cell for synchronization or control information used on the MBMS carrier.

[0082] In the current eMBMS structure, the synchronization signal can occur once every 5ms. For example, subframes 0 and 5 are ensured to be unicast so that the primary synchronization signal (PSS) / secondary synchronization signal (SSS) can be transmitted. However, converting these subframes (i.e., subframes 0 and 5 carrying PSS and SSS) into broadcast-only subframes removes the synchronization capability based on PSS and SSS.

[0083] Therefore, aspects of this disclosure provide methods for mitigating synchronization problems caused by the lack of synchronization signals for standalone LTE broadcast systems. For example, one potential method for assisting synchronization in a standalone LTE broadcast system could be generating modified PSS and SSS signals (e.g., PSS broadcast signal, SSS broadcast signal). According to some aspects, the PSS broadcast signal and SSS broadcast signal can be transmitted by the base station within a broadcast subframe in the system number (SFN) configuration (i.e., a synchronization sequence that is conventionally the same for multiple cells). However, several disadvantages may be associated with modifying the PSS / SSS signals. For example, the PSS broadcast signal and SSS broadcast signal can increase signaling overhead and consume resources that should be allocated to broadcast data. Furthermore, these signals may differ from the legacy PSS / SSS. For example, the parameter design of the standalone LTE broadcast subframe (e.g., symbol and CP duration, frequency modulation interval, pilot placement) may be very different from legacy unicast. These significant differences between the broadcast and unicast versions of the synchronization signal may require a new set of synchronization reception procedures.

[0084] Another method for assisted synchronization in standalone LTE broadcast systems involves time-division multiplexing (TDM) low-periodic unicast subframe bursts within the broadcast transmission, which allows the use of legacy LTE PSS / SSS to assist the LTE broadcast channel. As mentioned above, these unicast subframes can be transmitted sporadically with low periodicity (e.g., 80ms or 160ms) and can include PSS / SSS and Physical Broadcast Channel (PBCH) synchronization signals. Depending on some aspects, this technique allows most traffic to remain in LTE broadcast transmission, however at the cost of slower channel synchronization time.

[0085] Figure 6 The present disclosure describes example operations 600 for wireless communication that can be performed by, for example, a base station (e.g., base station 110). The eNB may include, for example... Figure 2 and 5 The components described herein, which can be configured to perform the operations described herein. For example, such as... Figure 2 The antenna 234, demodulator / modulator 232, controller / processor 240, and / or memory 242 described herein may perform the operations described herein. Additionally or alternatively, such as Figure 5 One or more of the processor 504, memory 506, transceiver 514, and / or antenna 516 described herein may be configured to perform the operations described herein.

[0086] Operation 600 begins at 602, transmitting a synchronization signal of the first type within anchor frames that occur periodically in the first period. At 604, the base station provides an indication of one or more unicast subframes scheduled to occur between anchor frames. At 606, the base station provides an indication of one or more broadcast subframes scheduled to occur between anchor frames.

[0087] Figure 7 Example operations 700 for wireless communication, which can be performed by, for example, user equipment (e.g., UE 120), according to various aspects of this disclosure, are explained. The UE may include, for example, user equipment (e.g., UE 120). Figure 2 and 5 The components described herein, which can be configured to perform the operations described herein. For example, such as... Figure 2 The antenna 252, demodulator / modulator 254, controller / processor 280, and / or memory 282 described herein may perform the operations described herein. Additionally or alternatively, such as Figure 5 One or more of the processor 504, memory 506, transceiver 514, and / or antenna 516 described herein may be configured to perform the operations described herein.

[0088] Operation 700 begins at 702, monitoring a synchronization signal of the first type within anchor subframes that occur periodically in the first period. At 704, the UE receives an indication of one or more unicast subframes scheduled to occur between anchor frames. At 706, the UE receives an indication of one or more broadcast subframes scheduled to occur between anchor frames. Depending on some aspects, the UE may receive both indications via, for example, one or more antennas 252. Although not shown, operation 700 may also include the UE receiving one or more unicast subframes and one or more broadcast subframes.

[0089] As described above, to help alleviate synchronization problems in standalone LTE broadcast systems, one or more legacy subframes can be transmitted with low periodicity for channel synchronization purposes. Depending on certain aspects, these legacy subframes can be represented as anchor frames and can be transmitted with a specific predefined periodicity (e.g., 80ms or 160ms). Additionally, anchor frames can carry PSS / SSS signals, which can be transmitted by the base station in known symbols within the subframe. For example, PSS / SSS signals used for broadcast synchronization can use the same assignments as legacy PSS / SSS signals. For instance, for frequency division duplex (FDD), the PSS can occupy the central 62 frequency moduli in the last symbol of the first time slot of the anchor frame, and the SSS can occupy the central 62 frequency moduli in the penultimate symbol of the first time slot of the anchor frame. Furthermore, for example, for time division duplex (TDD), the PSS can occupy the central 62 frequency moduli in the third symbol of the first time slot of the second anchor frame, and the SSS can occupy the central 62 frequency moduli in the last symbol of the second time slot of the first anchor frame. Although specific frequency modulation / symbol positions are provided, it should be understood that PSS / SSS frequency modulation / symbols can be located anywhere within the anchor frame.

[0090] Depending on certain aspects, the PBCH can also be transmitted by the base station within the anchor frame in a pre-defined resource allocation. For example, the PBCH can be transmitted in a manner similar to the legacy PBCH (i.e., non-standalone LTE broadcast), for instance, within the central 72 frequency modulations of the first four symbols in the second time slot of the anchor frame. Similarly, while specific frequency modulation / symbol locations are provided, it should be understood that the PBCH frequency modulations / symbols can be located anywhere within the anchor frame.

[0091] Additionally, according to certain aspects, by using PDCCH permission, the base station can transmit System Information Block (SIB) information and unicast PDSCH data within the anchor subframe, as well as any additional subframes allocated as unicast subframes, which will be described in more detail below.

[0092] Figure 8An example subframe transmission format for LTE standalone broadcasting is explained. As explained, an anchor frame (e.g., denoted as "A") may be transmitted first and may contain PSS / SSS, PBCH, SIB scheduling based on the Physical Downlink Control Channel (PDCCH), and PDCCH-based unicast transmission scheduling (e.g., indicating the number of unicast subframes to be transmitted after the anchor frame). Depending on some aspects, the transmission periodicity of the anchor frame (e.g., 80-160 ms) may be aligned with the radio frame, as explained. After the base station transmits the anchor frame, several unicast subframes (e.g., denoted as "U") may follow (e.g., as indicated by the scheduling information in the anchor frame). These unicast subframes may contain repetitions of the PSS / SSS and / or PBCH transmitted in the anchor frame, PDCCH-based SIB scheduling, and unicast transmission / data. Depending on some aspects, the duration of the unicast area may be defined in the master information block transmitted by the base station and monitored by the UE. Additionally, as explained, several broadcast subframes (e.g., denoted as "B") can be transmitted after a unicast subframe. Broadcast subframes may not have a PDCCH allocation and may have a large cyclic prefix (CP). Depending on various aspects, broadcast subframes may contain broadcast data, such as (e)MBMS data.

[0093] Depending on certain aspects, in order to successfully receive unicast and broadcast subframes, the MIB transmitted by the base station may need to include indications of unicast and broadcast subframes (e.g., Figure 8 The MIB (Mean Interchange Block) contains information about when unicast and broadcast subframes are scheduled. For example, the MIB may include system bandwidth, system frame number, and an indication of the subframe mode for unicast and broadcast subframe transmission. Additionally, for TDD, the MIB may include DL / UL configuration for unicast areas, as explained in more detail below. Depending on some aspects, upon receiving the MIB, the UE can determine the location of unicast subframes (e.g., for receiving additional SIB information and unicast traffic) and broadcast subframes, and monitor and receive / acquire these subframes within the determined locations.

[0094] Depending on certain aspects, repetition of the PSS / SSS synchronization signal and the PBCH can be required (e.g., similar to legacy systems) to achieve, for example, acceptable synchronization and performance metrics. For instance, a known fixed number of repetitions of the PSS / SSS and PBCH can be allowed periodically between a first anchor subframe and its repetitions. For example, refer to... Figure 8 A fixed number of repetitions of PSS / SSS and PBCH (e.g., transmitted within a unicast subframe) can be allowed between the first transmission 802 of the anchor frame and the second (repeated) transmission 804 of the anchor frame.

[0095] In some cases, the number of repetitions for each of the PSS, SSS, and / or PBCH can be changed independently, for example, to meet performance requirements. According to certain aspects, upon receiving the MIB, the UE can know the exact configuration and allocation of the PSS / SSS and the PBCH instance / repetition, and modify its receiver algorithm accordingly, for example, to improve reception performance. That is, the UE can modify its receiver algorithm to monitor and receive PSS / SSS / PBCH repetitions to improve reception performance.

[0096] In addition to receiving MIBs, the UE can also acquire one or more SIB transmissions, which can be transmitted by the base station in anchor and unicast subframes, for example... Figure 8 As explained, SIB transmissions can be scheduled by the base station via PDCCH (e.g., within anchor frames), and for each SIB (e.g., SIB1-SIB17), a different periodicity can be scheduled, which can be a multiple of the anchor frame periodicity. For example, SIB1 can be scheduled within each anchor frame transmission, while SIB3 can be scheduled every other anchor frame transmission.

[0097] Additionally, anchor frames and / or unicast subframes can be used by base stations to transmit other types of signals. For example, base stations can use anchor frames and / or unicast subframes to transmit legacy eMBMS broadcast signals, single-cell point-to-multipoint (SC-PTM) signals, and / or tilted carrier-new carrier type (NC) signals. In some cases, subscriber information or authentication / key information can be sent to specific users or specific user groups in these unicast subframes (e.g., acting as side channels).

[0098] The aspects presented below provide further details of the TDD implementation of independent LTE broadcast synchronization. For example, according to some aspects, after decoding the anchor subframe, the UE can know the DL / UL configuration of the unicast subframe based on the indication provided by the base station DL / UL subframe indication, as described above. For example, the UE can know a configurable number of DL subframes preceding a specific subframe, which may include a DL portion, a guard interval, and a UL portion, followed by a configurable number of UL subframes. This set of subframes may be followed by the broadcast portion.

[0099] Furthermore, within the UL portion of the unicast area, the base station can signal the configurable number of uplink subframes that can be converted into DL broadcast subframes on a per-cell basis, and can dynamically switch this based on broadcast load in each anchor subframe period. In other words, if a threshold amount of broadcast data needs to be transmitted, the base station can indicate to the UE that certain UL unicast subframes will be converted into broadcast subframes. The UE can then reconfigure its reception algorithm accordingly to receive the additional broadcast data. In some respects, this can be similar to LTE TDD Enhanced Interference Mitigation and Traffic Adaptation (eIMTA), where subframe configuration can be dynamically changed based on traffic load.

[0100] Synchronization options

[0101] It should be noted that while the above-mentioned techniques reduce synchronization problems in standalone LTE broadcast systems, these problems may still exist for some UEs in the wireless network. For example, in some cases, a UE may be within range of the transmitted single-frequency network (SFN) broadcast portion but unable to receive the transmitted unicast portion (e.g., the portion carrying the synchronization signal required by the UE to synchronize with the network).

[0102] For example, such as Figure 9 As explained, in some deployments where the inter-site distances of eNB 902 are relatively large (e.g., rural areas), coverage gaps may exist between unicast transmissions that vary depending on the cell (e.g., unicast coverage area 904) and SFN transmissions of eMBMS broadcast data (e.g., MBSFN coverage area 906). In other words, a UE outside the unicast coverage area may not be able to obtain a synchronization signal, even though it is within the coverage area of ​​the SFN eMBMS broadcast subframe. Therefore, aspects of this disclosure propose techniques for addressing synchronization problems in LTE standalone broadcast networks, for example, in cases where a UE is within broadcast transmission range but outside unicast transmission coverage.

[0103] Figure 10 The present disclosure describes example operations 1000 for wireless communication that can be performed by, for example, a base station (e.g., base station 110). The eNB may include, for example... Figure 2 and 5 The components described herein, which can be configured to perform the operations described herein. For example, such as... Figure 2 The antenna 234, demodulator / modulator 232, controller / processor 240, and / or memory 242 described herein may perform the operations described herein. Additionally or alternatively, such as Figure 5 One or more of the processor 504, memory 506, transceiver 514, and / or antenna 516 described herein may be configured to perform the operations described herein.

[0104] Operation 1000 begins at 1002, providing unicast coverage to one or more User Equipments (UEs) in a unicast coverage area within a larger coverage area. At 1004, the base station transmits unicast data in one or more subframes. At 1006, the base station transmits a synchronization signal in one or more broadcast subframes, wherein the broadcast signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area.

[0105] Figure 11 Example operations 1100 for wireless communication, which can be performed by, for example, user equipment (e.g., UE 120), according to various aspects of this disclosure, are explained. The UE may include, for example, user equipment (e.g., UE 120). Figure 2 and 5 The components described herein, which can be configured to perform the operations described herein. For example, such as... Figure 2 The antenna 252, demodulator / modulator 254, controller / processor 280, and / or memory 282 described herein may perform the operations described herein. Additionally or alternatively, such as Figure 5 One or more of the processor 504, memory 506, transceiver 514, and / or antenna 516 described herein may be configured to perform the operations described herein.

[0106] Operation 1100 begins at 1102, monitoring a synchronization signal within one or more broadcast subframes, wherein the synchronization signal is transmitted as a single-frequency network (SFN) transmission synchronized with transmissions from one or more other base stations providing unicast coverage over a larger coverage area. At 1104, the UE performs acquisition based on this synchronization signal. At 1106, the UE monitors unicast data in one or more subframes. Depending on some aspects, monitoring unicast data in one or more subframes may include monitoring unicast data in one or more unicast subframes occurring between broadcast subframes.

[0107] According to certain aspects, one way to address the problem that some UEs cannot receive the portion of unicast data carrying synchronization signals required for network synchronization during transmission is to transmit all or part of the unicast data in an SFN manner (e.g., where multiple cells simultaneously transmit the same signal / unicast transmission on the same frequency channel). For example, according to certain aspects, the base station can transmit all or part of the unicast data (e.g., including synchronization signals) in one or more broadcast subframes in an SFN manner.

[0108] In this scenario, the unicast portion transmitted via SFN can maintain legacy LTE parameter designs (e.g., the same legacy cyclic prefix length). Furthermore, all cells (e.g., base stations) in the LTE broadcast system can transmit the same PSS / SSS, ensuring that the signal carrying the unicast subframe is SFN. Depending on certain aspects, other unicast data can vary from cell to cell or can be the same across the MBSFN coverage area (i.e., SFN). Therefore, in certain deployment scenarios, these techniques can improve the UE's ability to acquire synchronization signals. For example, if the signal is transmitted via SFN, the UE can receive signals with diversity, which can significantly reduce interference because the UE no longer receives interference from distant cells.

[0109] According to certain aspects, another way to address the problem of some UEs being unable to receive the transmitted unicast portion could be to use broadcast SFN subframes to transmit synchronization signals (e.g., PSS / SSS) and / or MIB / SIB (e.g., as a supplement to the synchronization signals transmitted in the transmitted unicast portion). In this case, the SFN eMBMS broadcast synchronization signals can be periodically transmitted by the base station within the broadcast SFN subframe. For example, as Figure 12 As explained, synchronization signals and / or MIB / SIB can be periodically transmitted in broadcast SFN subframe 1202. Depending on various aspects, these SFN eMBMS synchronization signals can be designed using new eMBMS LTE parameters (e.g., a longer cyclic prefix length for eMBMS data, for example, the opposite of the cyclic prefix length for unicast data). Depending on various aspects, although... Figure 12 It is explained that multiple SFN eMBMS synchronization signals are transmitted within a broadcast SFN subframe (e.g., in 1202), but any number of SFN eMBMS synchronization signals (e.g., one) can be transmitted.

[0110] Additionally, in this configuration (i.e., using SFN eMBMS broadcast synchronization signals), the unicast portion 1204 can be maintained in the TDM structure along with the eMBMSSFN data, such as... Figure 12 As explained. For example, unicast portion 1204 can still be used to transmit unicast, cell-specific data (e.g., data specific to a particular cell). In some cases, the unicast portion can be eliminated by the base station (not explained). In this case, when the transmitted unicast portion is eliminated, the UE can be configured to use a broadcast synchronization signal (e.g., an SFN eMBMS broadcast synchronization signal) to obtain cell coverage. Additionally, in this case, since the unicast portion carrying cell-specific information is eliminated, non-cell-specific information can be transmitted.

[0111] According to certain aspects, in some situations, the UE may attempt cell acquisition based on one or both of a unicast synchronization signal and a broadcast synchronization signal. For example, in some situations, the UE may attempt to acquire the unicast synchronization signal. However, if the UE cannot acquire the unicast synchronization signal, the UE may then attempt to acquire the broadcast synchronization signal. According to certain aspects, the UE may perform the acquisition of the broadcast synchronization signal by blind decoding. Alternatively, the UE may attempt to acquire both the unicast synchronization signal and the broadcast synchronization signal simultaneously. Furthermore, in some situations, the UE may use the broadcast synchronization signal to assist (e.g., supplement) the unicast synchronization signal. For example, if there is a known alignment between the broadcast synchronization signal and the unicast synchronization signal, the timing associated with the broadcast synchronization signal, for example, can help determine the timing of the unicast synchronization signal.

[0112] Additionally, the UE can use the results of previous acquisition attempts to determine the acquisition type (e.g., determining which synchronization signal (broadcast and / or unicast) to attempt to acquire). For example, a static remote user who rarely or never accesses unicast synchronization signals can be configured to reduce attempts to acquire unicast synchronization signals and instead primarily attempt to acquire broadcast synchronization signals. That is, a UE that knows it typically cannot acquire unicast synchronization signals can abandon attempts to acquire unicast synchronization signals (e.g., for a period of time) and immediately attempt to acquire broadcast synchronization signals instead.

[0113] Transmission of multiple SIBs in a subframe

[0114] In some situations, subframes containing discovery and synchronization may need to convey multiple System Information Blocks (SIBs). For example, if discovery is performed every 40 ms (e.g., SIB reception), time-division multiplexing (TDM) of the SIBs may not be feasible without causing significant delays. Therefore, it may be necessary for subframes carrying discovery and synchronization signals to convey multiple SIBs, which may not be supported by current standards.

[0115] For example, SIB1 can be scheduled at a predetermined time, while other SIBs (e.g., SIB2, SIB3, etc.) are scheduled starting with SIB1 so that their transmissions do not overlap. Depending on the circumstances, each SIB can be addressed by the same System Information Radio Network Temporary Identifier (SI RNTI). Furthermore, since each SIB transmission does not overlap with any other SIB transmission, HARQ combining can be performed because there is no confusion about which SIB the UE is receiving (e.g., the UE can perform blind decoding based on the SI RNTI to determine which SIB is being received).

[0116] However, if multiple SI-RNTIs (i.e., multiple SIBs) are transmitted in the same subframe, the UE may become confused about which SIBs it is receiving. Therefore, aspects of this disclosure provide techniques for enabling multiple SIBs to be transmitted within the same subframe (e.g., a subframe carrying a synchronization signal as described above) so that there is no confusion about which SIB is being transmitted / received at any given time.

[0117] Figure 13 Example operations 1300 for wireless communication, which can be performed by, for example, a base station (e.g., base station 110), according to various aspects of this disclosure, are explained. The eNB may include, for example, Figure 2 and 5 The components described herein, which can be configured to perform the operations described herein. For example, such as... Figure 2 The antenna 234, demodulator / modulator 232, controller / processor 240, and / or memory 242 described herein may perform the operations described herein. Additionally or alternatively, such as Figure 5 One or more of the processor 504, memory 506, transceiver 514, and / or antenna 516 described herein may be configured to perform the operations described herein.

[0118] Operation 1300 begins at 1302, transmitting a synchronization signal of the first type within anchor subframes that occur periodically in the first period. At 1304, the base station provides an indication of one or more unicast subframes scheduled to occur between anchor frames. At 1306, the base station provides an indication of one or more broadcast subframes scheduled to occur between anchor frames. At 1308, the base station transmits a plurality of System Information Blocks (SIBs) in at least one of the first anchor frame of the anchor frames or the first unicast subframe of the one or more unicast subframes. Although not shown, operation 1300 may also include transmitting a synchronization signal within one or more broadcast subframes, and transmitting at least one of unicast data or broadcast data in one or more corresponding unicast or broadcast subframes.

[0119] Figure 14 Example operations 1400 for wireless communication, which can be performed by, for example, user equipment (e.g., UE 120), according to various aspects of this disclosure, are explained. The UE may include, for example, user equipment (e.g., UE 120). Figure 2 and 5 The components described herein, which can be configured to perform the operations described herein. For example, such as... Figure 2 The antenna 252, demodulator / modulator 254, controller / processor 280, and / or memory 282 described herein may perform the operations described herein. Additionally or alternatively, such as Figure 5 One or more of the processor 504, memory 506, transceiver 514, and / or antenna 516 described herein may be configured to perform the operations described herein.

[0120] Operation 1400 begins at 1402, monitoring a first type of synchronization signal within an anchor subframe that occurs periodically. At 1404, the UE receives an indication of one or more unicast subframes scheduled to occur between anchor frames. At 1406, the UE receives an indication of one or more broadcast subframes scheduled to occur between anchor frames. At 1408, the UE receives multiple System Information Blocks (SIBs) within at least one of the first anchor frame of the anchor frame or the first unicast subframe of the one or more unicast subframes. Although not shown, operation 1400 may also include monitoring synchronization signals within one or more broadcast subframes, and monitoring at least one of unicast data or broadcast data within one or more corresponding unicast or broadcast subframes.

[0121] As mentioned above, multiple SIBs can be transmitted / received within the same subframe, which can be achieved, for example, by configuring the UE to monitor different permissions corresponding to different SIBs within the same subframe.

[0122] In some respects, to distinguish between different SIBs, the base station can generate (and transmit) each SIB with a different SI-RNTI. The base station can then transmit multiple downlink grants, including SI-RNTIs for each different SIB to be transmitted. The UE can then monitor the downlink grants with different SI-RNTIs to find different SIBs. Based on the downlink grants, the UE can monitor (and receive in the same subframe) the SIBs corresponding to the SI-RNTI identified in the downlink grant. Furthermore, since each received SIB is identified by a unique SI-RNTI, for example, when multiple SIBs are received in the same subframe, the UE can determine the type of the received SIB (e.g., SIB1, SIB2, etc.) based on this unique SI-RNTI.

[0123] In some cases, the SI-RNTI of SIB1 can be fixed in the specification or may depend on the Physical Cell Identifier (PCID). According to certain aspects, when SIB1 schedules other SIBs, it can also signal the corresponding SI-RNTI of those other SIBs. For example, assuming SIB1 and SIB2 are transmitted by a base station in the same subframe, SIB1 and SIB2 can use different SI-RNTIs, where the SI-RNTI of SIB1 can be fixed (e.g., in the standard) or based on the PCID, and the SI-RNTI of SIB2 can be signaled in SIB1. According to certain aspects, if SIBs are time-division multiplexed (TDM), the same SI-RNTI can be used for SIBs in different subframes. For example, assuming SIB19 is TDM-multiplexed with the SIBs preceding it, SIB19 can reuse, for example, the SI-RNTI of SIB1, because there will be no confusion at the UE. For example, since SI-RNTIs can be mapped to specific subframes, the UE can determine the actual SIB being transmitted. In other words, knowledge of subframe timing allows the UE to potentially use the same SI-RNTI without any confusion in determining which SIB was transmitted. Additionally, according to certain aspects, instead of semi-static signaling for SI-RNTI (e.g., in SIB1), standard documentation can contain fixed SI-RNTIs for each SIB after SIB1.

[0124] According to some aspects, another way to distinguish SIBs transmitted in the same subframe is for the base station to provide an indication in a field of the (e.g., permitted) downlink control information (DCI) which SIBs are being transmitted in the subframe. According to some aspects, this field can be a new field or use some reserved bits in the permitted field. Additionally, according to some aspects, the SIB1 value of this field can be defined in the specification document (or depending on the PCID). Field values ​​for other SIBs can be fixed in the specification document or indicated by signaling in SIB1. According to some aspects, if SIBs are time-division multiplexed (TDM), the same SI-RNTI can be used for SIBs in different subframes. For example, assuming SIB19 is TDM with the SIBs preceding it, SIB19 can reuse, for example, the SIB1 SI-RNTI because there will be no confusion at the UE, as stated above. Additionally, according to some aspects, instead of semi-static signaling for SI-RNTIs (e.g., in SIB1), the standard document can include fixed SI-RNTIs for each SIB after SIB1.

[0125] According to some sources, even when the base station transmits multiple SIBs simultaneously, the UE may not be required to monitor each SIB at the same time, for example, because not all SIBs are required to be processed at the same rate.

[0126] Depending on certain aspects, additional information may be carried in the synchronization channel (e.g., carrying the synchronization signal as described above) or in the physical broadcast channel (PBCH) indicating the scheduling of the SIB (especially SIB1). For example, the PBCH or synchronization channel may include bits indicating whether the base station is an independent MBMS or a subcell (Scell) MBMS. In such cases, the SIB1 periodicity and subframe allocation may change every 40ms from subframe 5 to subframe 0.

[0127] As used herein, the phrase “at least one of” refers to any combination of these items, including a single member. As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbb, cc, and ccc, or any other ordering of a, b, and c).

[0128] As used herein, the term "identifier" encompasses a wide variety of actions. For example, "identifier" can include calculation, computation, processing, derivation, research, searching (e.g., searching in a table, database, or other data structure), discovery, and the like. Furthermore, "identifier" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and similar actions. Moreover, "identifier" can also include parsing, selecting, choosing, establishing, and similar actions.

[0129] In some cases, instead of actually transmitting frames, a device may have an interface for transmitting or receiving frames. For example, a processor may output frames to an RF front end for transmission via a bus interface. Similarly, a device may not actually receive frames, but may have an interface for obtaining frames received from another device. For example, a processor may obtain (or receive) frames from an RF front end for transmission via a bus interface.

[0130] The methods disclosed herein include one or more steps or actions for achieving the described methods. These method steps and / or actions may be interchanged with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims.

[0131] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means may include various hardware and / or software / firmware components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. Generally, where the operations illustrated in the accompanying drawings are present, these operations may have corresponding paired means plus functional components.

[0132] The various operations of the methods described above can be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software / firmware components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. Generally, in the context of operations illustrated in the accompanying drawings, those operations can be performed by any suitable corresponding paired device plus functional components.

[0133] For example, means for transmitting, means for retransmitting, means for sending, and / or means for providing may include a transmitter, which may include... Figure 2 The base station 110 described in the text includes a transmit processor 220, a TX MIMO processor 230, a demodulator / modulator 232a-232t, and / or an antenna 234a-234t. Figure 2 The user equipment 120 described in the middle includes a transmitter processor 264, a TX MIMO processor 266, a demodulator / modulator 254a-254r, and / or an antenna 252a-252r; and / or Figure 5 The wireless device 502 described in the text includes a transmitter 510, a DSP 520, and / or an antenna 516.

[0134] The means for receiving and / or the means for acquiring may include a receiver, which may include Figure 2 The base station 110 described in the text includes a receiver processor 238, a MIMO detector 236, a demodulator / modulator 232a-232t, and / or an antenna 234a-234t. Figure 2 The user equipment 120 provided in the middle of the package includes a receiver processor 258, a MIMO detector 256, a demodulator / modulator 254a-254r, and / or an antenna 252a-252r; and / or Figure 5 The wireless device 502 described in the text includes a receiver 512, a DSP 520, a signal detector 518, and / or an antenna 516.

[0135] The means for determining, the means for performing, the means for monitoring, and / or the means for changing may include a processing system, which may include... Figure 2 The controller / processor 240 and / or other processors of the base station 110 described in the text; Figure 2The user equipment described in the middle has 120 controllers / processors 280 and / or other processors; and / or Figure 5 The processor 504 of the wireless device 502 explained in the text.

[0136] Those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and skills. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or light particles, or combinations thereof.

[0137] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with this disclosure can be implemented as electronic hardware, software / firmware, or a combination thereof. To clearly illustrate this interchangeability between hardware and software / firmware, the various illustrative components, blocks, modules, circuits, and steps are described above in a generalized manner in terms of their functionality. Whether such functionality is implemented as hardware or software / firmware depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be construed as departing from the scope of this disclosure.

[0138] The various illustrative logic blocks, modules, and circuits described herein can be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), 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. The general-purpose processor may be a microprocessor, but in alternatives, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0139] The steps of the methods or algorithms described herein may be embodied directly in hardware, in a software / firmware module executed by a processor, or in a combination thereof. The software / firmware module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, phase-change memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. Alternatively, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0140] In one or more exemplary designs, the described functionality may be implemented in hardware, software / firmware, or a combination thereof. If implemented in software / firmware, the functionality may be stored or transmitted as one or more instructions or code on or through a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a general-purpose or special-purpose computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD / DVD or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software / firmware is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then those coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media. As used herein, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

[0141] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication by a wireless node, comprising: Transmit a first type of synchronization signal within an anchor frame that occurs periodically in the first period; Provides an indication of one or more unicast subframes scheduled to occur between anchor subframes; Provides an indication of one or more broadcast subframes scheduled to occur between anchor subframes; Multiple different System Information Blocks (SIBs) are transmitted in at least one of the first anchor frame of the anchor subframe or the first unicast subframe of the one or more unicast subframes. The plurality of different SIBs do not include the main information block (MIB), each of the plurality of different SIBs is associated with a different identifier, and at least one identifier associated with one of the plurality of different SIBs is signaled in another of the plurality of different SIBs.

2. The method as described in claim 1, wherein, At least one of the different identifiers depends on the cell identifier.

3. The method as described in claim 1, wherein, At least one of the identifiers used for a first type of SIB among the plurality of different SIBs is reused from a previous subframe, in which the same identifier was used for a second type of SIB that is different from the first type of SIB.

4. The method of claim 1, further comprising providing an indication of the SIB type being transmitted via downlink control information (DCI).

5. A method for wireless communication by a user equipment (UE), comprising: Monitor the first type of synchronization signal within the anchor frame that occurs in the first periodicity; Obtain an indication of one or more unicast subframes scheduled to occur between anchor subframes; Obtain an indication of one or more broadcast subframes scheduled to occur between anchor subframes; as well as Obtain multiple different System Information Blocks (SIBs) in at least one of the first anchor frame of the anchor subframe or the first unicast subframe of the one or more unicast subframes. The plurality of different SIBs do not include the main information block (MIB), each of the plurality of different SIBs is associated with a different identifier, and at least one identifier associated with one of the plurality of different SIBs is signaled in another of the plurality of different SIBs.

6. The method of claim 5, wherein, At least one of the different identifiers depends on the cell identifier.

7. The method of claim 5, wherein, At least one of the aforementioned identifiers is specified in the standard.

8. The method of claim 5, wherein, At least one of the identifiers used for a first type of SIB among the plurality of different SIBs is reused from a previous subframe, in which the same identifier was used for a second type of SIB that is different from the first type of SIB.

9. The method of claim 5, further comprising determining the type of the first SIB based at least in part on an identifier associated with a first SIB among the plurality of different SIBs.

10. The method of claim 5, further comprising providing an indication of the SIB type being transmitted via downlink control information (DCI).

11. An apparatus for wireless communication, the apparatus comprising: At least one processor; as well as A memory coupled to the at least one processor, the memory including instructions executable by the at least one processor to cause the device to perform the following operations: Transmit a first type of synchronization signal within an anchor frame that occurs periodically in the first period; Provides an indication of one or more unicast subframes scheduled to occur between anchor subframes; Provides an indication of one or more broadcast subframes scheduled to occur between anchor subframes; Multiple different System Information Blocks (SIBs) are transmitted in at least one of the first anchor frame of the anchor subframe or the first unicast subframe of the one or more unicast subframes. The plurality of different SIBs do not include the main information block (MIB), each of the plurality of different SIBs is associated with a different identifier, and at least one identifier associated with one of the plurality of different SIBs is signaled in another of the plurality of different SIBs.

12. The apparatus of claim 11, wherein the memory further comprises instructions executable by the at least one processor to cause the apparatus to perform the method of any one of claims 2-4.

13. An apparatus for wireless communication, the apparatus comprising: At least one processor; as well as A memory coupled to the at least one processor, the memory including instructions executable by the at least one processor to cause the device to perform the following operations: Monitor the first type of synchronization signal within the anchor frame that occurs in the first periodicity; Obtain an indication of one or more unicast subframes scheduled to occur between anchor subframes; Obtain an indication of one or more broadcast subframes scheduled to occur between anchor subframes; as well as Obtain multiple different System Information Blocks (SIBs) in at least one of the first anchor frame of the anchor subframe or the first unicast subframe of the one or more unicast subframes. The plurality of different SIBs do not include the main information block (MIB), each of the plurality of different SIBs is associated with a different identifier, and at least one identifier associated with one of the plurality of different SIBs is signaled in another of the plurality of different SIBs.

14. The apparatus of claim 13, wherein the memory further comprises instructions executable by the at least one processor to cause the apparatus to perform the method of any one of claims 6-10.

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