WO2019100264A1

WO2019100264A1 - Enhancements of nb-iot for tdd operation

Info

Publication number: WO2019100264A1
Application number: PCT/CN2017/112363
Authority: WO
Inventors: Chao Wei; Alberto Rico Alvarino; Le LIU; Wanshi Chen
Original assignee: Qualcomm Incorporated
Priority date: 2017-11-22
Filing date: 2017-11-22
Publication date: 2019-05-31

Abstract

For DL in DwPTS, systems and methods herein utilize a resource mapping schemes that are dependent on whether or not cyclic repetition is used. The proposed solution is beneficial for enabling symbol level combination in case of cyclic repetition and improving the performance for non-cyclic repetition case. For supporting coexistence with eIMTA, systems and methods herein configure separate reference UL/DL configurations for DL reception, UL transmission and control monitoring. The validity window of the reference configuration may be driven by UL or DL grants and the repetition level indicated. Further, data scrambling for NB-IoT TDD may be improved by using more LSBs of the frame index and/or introducing a block counter to avoid repeating the same scrambling sequence for repetition transmissions.

Description

ENHANCEMENTS OF NB-IOT FOR TDD OPERATION

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to acquisition of radio frequency impairment parameters over the air in a wireless communication system. Certain embodiments of the technology discussed below can enable and provide efficient estimation of radio frequency (RF) link impairments, such as associated with linear and non-linear distortions, by a receiver device and acquiring RF link impairment information over the air by a transmitter device, such as to implement RF link impairments correction.

INTRODUCTION

Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources.

A wireless communication network may include a number of base stations or node Bs that can support communication for a number of user equipments (UEs) . A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlink to a UE and/or may receive data and control information on the uplink from the UE. On the downlink, a transmission from the base station may encounter interference due to transmissions from neighbor base stations or from other wireless radio frequency (RF) transmitters. On the uplink, a transmission from the UE may encounter interference from uplink transmissions of other UEs communicating with the neighbor base stations or from other wireless RF transmitters. This interference may degrade performance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, the possibilities of interference and congested networks grows with more UEs accessing the long-range wireless communication networks and more short-range wireless systems being deployed in communities. Research and development continue to advance wireless communication technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

BRIEF SUMMARY OF SOME EMBODIMENTS

The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the present disclosure may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wireless communication system according to some embodiments of the present disclosure.

FIG. 2 is a block diagram conceptually illustrating a design of a base station/gNB and a UE configured according to some embodiments of the present disclosure.

FIG. 3A is an example system diagram of example embodiments herein.

FIG. 3B is an example system diagram of example embodiments herein.

FIG. 3C is an example configuration of example embodiments herein.

FIG. 3D is an example configuration of example embodiments herein.

FIG. 3E is an example configuration of example embodiments herein.

FIG. 3F is an example diagram of example embodiments herein.

FIG. 4A is an example configuration of example embodiments herein.

FIG. 4B is an example diagram of example embodiments herein.

FIG. 4C is an example diagram of example embodiments herein.

FIG. 4D is an example diagram of example embodiments herein.

APPENDIX attached is an appendix which is incorporated herein by reference and provides additional information regarding embodiments described herein.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with the appended drawings, is intended as a description of various possible configurations and is not intended to limit the scope of the disclosure. Rather, the detailed description includes specific details for the purpose of providing a thorough understanding of the inventive subject matter. It will be apparent to those skilled in the art that these specific details are not required in every case and that, in some instances, well-known structures and components are shown in block diagram form for clarity of presentation.

This disclosure relates generally to providing or participating in communication as between two or more wireless devices in one or more wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, long term evolution (LTE) networks, Global System for Mobile Communications (GSM) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably according to the particular context.

A CDMA network, for example, may implement a radio technology such as universal terrestrial radio access (UTRA) , cdma2000, and the like. UTRA includes wideband-CDMA (W-CDMA) and low chip rate (LCR) . CDMA2000 covers IS-2000, IS-95, and IS-856 standards.

A TDMA network may, for example implement a radio technology such as GSM. 3GPP defines standards for the GSM EDGE (enhanced data rates for GSM evolution) radio access network (RAN) , also denoted as GERAN. GERAN is the radio component of GSM/EDGE, together with the network that joins the base stations (for example, the Ater and Abis interfaces) and the base station controllers (Ainterfaces, etc. ) . The radio access network represents a component of a GSM network, through which phone calls and packet data are routed from and to the public switched telephone network (PSTN) and Internet to and from subscriber handsets, also known as user terminals or user equipments (UEs) . A mobile phone operator′s network may comprise one or more GERANs, which may be coupled with Universal Terrestrial Radio Access Networks (UTRANs) in the case of a UMTS/GSM network. An operator network may also include one or more LTE networks, and/or one or more other networks. The various different network types may use different radio access technologies (RATs) and radio access networks (RANs) .

An OFDMA network may, for example, implement a radio technology such as evolved UTRA (E-UTRA) , IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and GSM are part of universal mobile telecommunication system (UMTS) . In particular, LTE is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP) , and cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . These various radio technologies and standards are known or are being developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is a 3GPP project aimed at improving the universal mobile telecommunications system (UMTS) mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices.

For clarity, certain aspects of the apparatus and techniques may be described below with reference to exemplary LTE implementations or in an LTE-centric way, and LTE terminology may be used as illustrative examples in portions of the description below; however, the description is not intended to be limited to LTE applications. Indeed, the present disclosure is concerned with shared access to wireless spectrum between networks using different radio access technologies or radio air interfaces.

Moreover, it should be understood that, in operation, wireless communication networks adapted according to the concepts herein may operate with any combination of licensed or unlicensed spectrum depending on loading and availability. Accordingly, it will be apparent to one of skill in the art that the systems, apparatus and methods described herein may be applied to other communications systems and applications than the particular examples provided.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and/or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, etc. ) . While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregated, distributed, or OEM devices or systems incorporating one or more described aspects. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. It is intended that innovations described herein may be practiced in a wide variety of implementations, including both large/small devices, chip-level components, multi-component systems (e.g. RF-chain, communication interface, processor) , distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

FIG. 1 shows wireless network 100 for communication according to some embodiments. While discussion of the technology of this disclosure is provided relative to an LTE-A network (shown in FIG. 1) , this is for illustrative purposes. Principles of the technology disclosed can be used in other network deployments, including fifth generation (5G) networks. As appreciated by those skilled in the art, components appearing in FIG. 1 are likely to have related counterparts in other network arrangements including, for example, cellular-style network arrangements and non-cellular-style-network arrangements (e.g., device to device or peer to peer or ad hoc network arrangements, etc. ) .

Turning back to FIG. 1 wireless network 100 includes a number of base stations, such as may comprise evolved node Bs (eNBs) or G node Bs (gNBs) . These may be referred to as gNBs 105. A gNB may be a station that communicates with the UEs and may also be referred to as a base station, a node B, an access point, and the like. Each gNB 105 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a gNB and/or a gNB subsystem serving the coverage area, depending on the context in which the term is used. In implementations of wireless network 100 herein, gNBs 105 may be associated with a same operator or different operators (e.g., wireless network 100 may comprise a plurality of operator wireless networks) , and may provide wireless communications using one or more of the same frequencies (e.g., one or more frequency band in licensed spectrum, unlicensed spectrum, or a combination thereof) as a neighboring cell.

A gNB may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto celt, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . A gNB for a macro cell may be referred to as a macro gNB. A gNB for a small cell may be referred to as a small cell gNB, a pico gNB, a femto gNB or a home gNB. In the example shown in FIG. 1,

gNBs

105a, 105b and 105c are macro gNBs for the

macro cells

110a, 110b and 110c, respectively.

gNBs

105x, 105y, and 105z are small cell gNBs, which may include pico or femto gNBs that provide service to

small cells

110x, 110y, and 110z, respectively. A gNB may support one or multiple (e.g., two, three, four, and the like) cells.

Wireless network 100 may support synchronous or asynchronous operation. For synchronous operation, the gNBs may have similar frame timing, and transmissions from different gNBs may be approximately aligned in time. For asynchronous operation, the gNBs may have different frame timing, and transmissions from different gNBs may not be aligned in time. In some scenarios, networks may be enabled or configured to handle dynamic switching between synchronous or asynchronous operations.

UEs 115 are dispersed throughout wireless network 100, and each UE may be stationary or mobile. It should be appreciated that, although a mobile apparatus is commonly referred to as user equipment (UE) in standards and specifications promulgated by the 3rd Generation Partnership Project (3GPP) , such apparatus may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. Within the present document, a “mobile” apparatus or UE need not necessarily have a capability to move, and may be stationary. Some non-limiting examples of a mobile apparatus, such as may comprise embodiments of one or more ofUEs 115, include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC) , a notebook, a netbook, a smart book, a tablet, and a personal digital assistant (PDA) . A mobile apparatus may additionally be an “Internet of things” (IoT) device such as an automotive or other transportation vehicle, a satellite radio, a global positioning system (GPS) device, a logistics controller, a drone, a multi-copter, a quad-copter, a smart energy or security device, a solar panel or solar array, municipal lighting, water, or other infrastructure; industrial automation and enterprise devices; consumer and wearable devices, such as eyewear, a wearable camera, a smart watch, a health or fitness tracker, a mammal implantable device, gesture tracking device, medical device, a digital audio player (e.g., MP3 player) , a camera, a game console, etc. ; and digital home or smart home devices such as a home audio, video, and multimedia device, an appliance, a sensor, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus, such as UEs 115, may be able to communicate with macro gNBs, pico gNBs, femto gNBs, relays, and the like. In FIG. 1, a lightning bolt (e.g., communication links 125) indicates wireless transmissions between a UE and a serving gNB, which is a gNB designated to serve the UE on the downlink and/or uplink, or desired transmission between gNBs. Although backhaul communication 134 is illustrated as wired backhaul communications that may occur between gNBs, it should be appreciated that backhaul communications may additionally or alternatively be provided by wireless communications.

FIG. 2 shows a block diagram of a design of base station/gNB 105 and UE 115. These can be one of the base stations/gNBs and one of the UEs in FIG. 1. For a restricted association scenario (as mentioned above) , the gNB 105 may be small cell gNB 105z in FIG. 1, and UE 115 may be UE 115z, which in order to access small cell gNB 105z, would be included in a list of accessible UEs for small cell gNB 105z. gNB 105 may also be a base station of some other type. gNB 105 may be equipped with antennas 234a through 234t, and UE 115 may be equipped with antennas 252a through 252r.

At gNB 105, transmit processor 220 may receive data from data source 212 and control information from controller/processor 240. The control information may be for the physical broadcast channel (PBCH) , physical downlink control channel (PDCCH) , etc. The data may be for the physical downlink shared channel (PDSCH) , etc. Transmit processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processor 220 may also generate reference symbols, e.g., for the primary synchronization signal (PSS) and secondary synchronization signal (SSS) . Transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or reference symbols, if applicable, and may provide output symbol streams to modulators (MODs) 232a through 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 additionally or alternatively process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a through 232t may be transmitted via antennas 234a through 234t, respectively.

At UE 115, antennas 252a through 252r may receive the downlink signals from gNB 105 and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc. ) to obtain received symbols. MIMO detector 256 may obtain received symbols from all demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 115 to data sink 260, and provide decoded control information to controller/processor 280.

On the uplink, at UE 115, transmit processor 264 may receive and process data (e.g., for the PUSCH) from data source 262 and control information (e.g., for the PUCCH) from controller/processor 280. Transmit processor 264 may also generate reference symbols for a reference signal. The symbols from transmit processor 264 may be precoded by TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for SC-FDM, etc. ) , and transmitted to gNB 105. At gNB 105, the uplink signals from UE 115 may be received by antennas 234, processed by demodulators 232, detected by MIMO detector 236 if applicable, and further processed by receive processor 238 to obtain decoded data and control information sent by UE 115. Processor 238 may provide the decoded data to data sink 239 and the decoded control information to controller/processor 240.

Controllers/

processors

240 and 280 may direct the operation at gNB 105 and UE 115, respectively. Controller/processor 240 and/or other processors and modules at gNB 105 and/or controllers/processor 280 and/or other processors and modules at UE 115 may perform or direct the execution of various processes for the techniques described herein, such as to perform or direct the execution illustrated in all of the FIGS., and/or other processes for the techniques described herein.

Memories

242 and 282 may store data and program codes for gNB 105 and UE 115, respectively. Scheduler 244 may schedule UEs for data transmission on the downlink and/or uplink.

Handling of Special Subframes

LTE TDD (Long Term Evolution Time Divisional Duplex) may use special subframes that include DwPTS (Downlink Pilot Time Slots) , GPs (gaps) , and UpPTS (Uplink Pilot Time Slots) . Special frames include DwPTS and UpPTS to increase data throughput of other subframes (e.g., normal subframes) via the use of pilot symbols. Special frames may include GPs located between DwPTSs and UpPTSs to help prevent collisions and provide overall better performance of the communication systems.

In traditional communication systems, a DwPTS transmission may occur when the number of symbols of the DwPTS reach a value larger than three. Heretofore, to simplify these traditional designs, DwPTSs have previously not been supported for NB-IoT TDD (Narrowband-Internet of Things Time Division Duplex) . However, proposals herein determined that this simplified traditional design significantly degrades DL throughput especially when the downlink subframes are limited with certain UL/DL (uplink/downlink) configuration. It is noted that special subframes include a less number of DL OFDMs (Downlink Orthogonal Frequency Division Multiplexing) as compared non-special DL frames (e.g., regular DL subframes, normal DL subframes, Further, special subframes may have a different NRS (Narrowband Reference Signal) pattern as compared to a normal subframe’s NRS. Further still, the start symbol position of a special subframe may be in a different location as compared to the start symbol position of a normal subframe.

In NB-IoT, a single transport block for NPDSCH (Narrowband Physical Downlink Shared Channel) may be mapped to multiple subframes. Part of those multiple subframes may include one or more special subframe. While such a configuration provides some advantages, the configuration comes at a cost, and that cost involves increased complexity. In the case of repetition transmission, it may also be possible that a first part of a repetition transmission may include a special subframe while another part of the repetition transmission does not include a special subframe. Again, advantages are realized from this design, but still again, the price of complexity rises further still. According to current designs, supporting the DwPTS of a special subframe is comparatively more complex than supporting DL transmissions of normal subframes.

This increased complexity cause technical problems to the wireless communication industry, especially in light of the industry’s movements to reduce the power usage of devices. Solutions herein propose technical solutions to these problems caused by the increased complexities associated with special frames. The solutions treat DwPTS of special subframes differently from the DLs of normal subframes when and/or if different treatment is determined to be appropriate.

The proposed solutions herein recognized that systems and methods herein may benefit from making resource mapping schemes dependent on whether cyclic repetition is used or not used (e.g., using simple repetition instead) .

In certain circumstances, repetition schemes other than cyclic repetition may be sufficient to transmit DwPTS of special frames. Further, certain resource mapping schemes may reduce the complexity of systems and methods of wireless communication systems. As such, making resource mapping schemes contingent on the type of repetition method employed in a given transmission provides a technical improvement to wireless communications systems by reducing processing complexity and communication traffic.

An example solution uses a simple repetition instead of cyclic repetition because in some circumstances system performance may be improved by avoiding the complexity of cyclic repetition. In a simple repetition, systems and methods may perform rate mapping around DwPTS according to different numbers of complex symbols for each repetitions (and/or some repetitions) . An illustration of a simple repetition example is shown in FIG. Ba. Certain downlink transmissions may be advantaged by avoiding cyclic repetition, for example, NPDCCHs (narrowband physical downlink control channel) without repetition. Further, it may be advantageous to avoid cyclic repetition for NPDSCH (narrowband physical downlink shared channel) without repetition. Further still, it may be advantageous to avoid cyclic repetition for an NPDSCH (narrowband physical downlink shared channel) carrying a system information broadcast (SIB) . If it is determined that an advantage may be realized by avoiding cyclic repetition, simple repetition may be used and resource mapping (RP) may be done according to all available REs (Resource Elements) of the allocated subframes. Using this solution, resource mapping for each repetition may be different based on whether a particular subframe of each repetition includes a special subframe.

In another example, it may be advantageous to use a cyclic repetition. An illustration of a cyclic repetition example is shown in FIG. Bb. Certain downlink transmissions may be advantaged by utilizing cyclic repetition, for example when an NPDSCH (narrowband physical downlink shared channel) is not carrying system information broadcast (SIB) , and further when an NPDSCH and/or NPDCCH will repeat more than once. In cyclic repetition, for each allocated subframe, the resource mapping is done similar to that of a normal DL subframe and puncturing is performed to account for the reduced number of OFDM symbols in DwPTS.

As explained above, making resource mapping schemes contingent on the type of repetition method employed in a given transmission provides a technical improvement to wireless communications systems by reducing processing complexity and communication traffic. A cyclic repetition proposed solution is beneficial in certain circumstances because it enables symbol-level combination across normal and special subframes. In embodiments, systems and method puncture the first few OFMD symbols (e.g., symbols in normal DL subframes minus the number of symbols in the special subframe) instead of the last few OFDM symbols so that identical repetition is supported for special subframe.

For NPDCCH (narrowband physical downlink control channel) monitoring, embodiments may constraint to a two CCE (control channel element) in the case of a special subframe. For example, a UE (user equipment) may limit itself to monitoring a two CCE for single repetition instead of monitoring for both a one CCE and a two CCE, as is done in a normal DL subframe. For example, the coding rate for one CCE in special subframe is higher than 0.5 thus may be difficult to decode for low SNR (signal to noise ration) . A further advantage is that for short DwPTS, embodiments may use a single pair ofNRS (narrowband reference signal) symbols at the end of the first slot, and as such, a second pair of NRS symbols may be omitted. Examples are shown in FIG. C. Embodiments, as described above, may be particularly beneficial when used with low power devices.

FIG. 3F illustrates an example method 300 being performed by a system, apparatus, and/or device that send special downlink transmissions. In this example, data is being prepared for transmission via DwPTS of a special subframe. A processor determines the type of data that will be downlinked via a special subframe. At step 301, a control processor determines what type of data will be transmitted. In examples, the subframe type may be a normal DL subframe or a special subframe. In step 303, the processor determines based on the type of data being downlinked, whether the subframe should be organized using simple repetition. Ifstep 303 determines that simple repetition should be used, then the method moves to step 305, wherein the processor applies a resource mapping specifically associated with simple repetition. The resource mapping scheme of step 305 uses all available resource elements of the allocated frames. Once the data is resource mapped, at step 306 the data is send to one or more transmitter and transmitted via one or more antenna.

If, based on the type of data being downlinked, step 303 determines that simple repetition not should be used, then the method moves to step 307, wherein the processor determines whether cyclic repetition should be used when downlinking the data. If step 307 determines that cyclic repetition should be used, then the method moves to step 309, wherein the processer applies a resource mapping scheme specifically associated with cyclic repetition. In embodiments, this resource mapping of the special frame may be the same or similar the resource mapping that is used when resource mapping normal downlinks. In embodiments, this resource mapping of the special frame may be different from the resource mapping that is used when resource mapping normal downlinks. In embodiments, the resource mapping of step 309 may include puncturing (see optional step 3011) . In embodiments, the resource mapping of step 309 may include symbol level combination (see optional step 3013) . Once the data is resource mapped, at step 310 the data is send to one or more transmitter and transmitted via one or more antenna. Method 300 may be repeated as desired when downlinking additional data in special frames.

Supporting Dynamic TDD

Supporting coexistence with enhanced interference mitigation and traffic adaptation (eIMTA) is desired. For LTE (long term evolution) inband deployment, dynamic TDD UL/DL (time division duplex uplink/downlink) reconfiguration may be used for the inband LTE system. Fig. 4a shows an example frame 400a wherein some subframes have a flexible direction and some subframes have a fix direction. In example frame 400a, subframe 401 is a fixed subframe and is fixed to be a downlink normal subframe, subframe 402 is a fixed subframe and is fixed to be a special subframe, subframe 403 is a fixed subframe and is fixed to be an uplink normal subframe, subframe 404 is a flexible subframe and may be either an uplink normal subframe or a downlink normal subframe, subframe 405 is a flexible subframe and may be either an uplink normal subframe or a downlink normal subframe, subframe 406 is a fixed subframe and is fixed to be a downlink normal subframe, subframe 407 is a flexible subframe and may be either special subframe or a downlink normal subframe, subframe 408 is an flexible subframe and may be either an uplink normal subframe or a downlink normal subframe, and subframe 410 is a fixed subframe and is fixed to be a downlink normal subframe.

However, systems and methods herein have discovered that it is difficult for NB-IoT TDD UE (Narrowband Internet of Things Time Division Duplex User Equipment) to listen to a DCI (Downlink Control Information) reconfiguration and determine direction of a given subframe. For example, a NB-IoT TTD UE may have difficulties determining the designation of subframe 407 based on the reconfigurable DCI. This may lead to misalignment between a eNB and a NB-IoT UE regarding a subframe transmission direction, which causes problems in the communication system.

Systems and methods herein propose technical solutions to the described problems. The goal is to support dynamic TDD for inband LTE system. The goal may be achieved by configuring separate reference UL/DL configurations for DL reception, UL transmission, and control monitoring.

In example, systems and methods may define a DL reference configuration for DL data reception. For example, a DL data reception may be defined as being DL heavy and or UL/DL configuration. Further, systems and methods may define an UL reference configuration for UL data transmissions. For example, an UL reference configuration may be defines as being UL heavy and or UL/DL configuration. Further still, systems and methods may define a control reference configuration for receiving control information. For example, a control reference configuration may be defined as being an UL/DL configuration in SIB 1 (system information block type 1) .

FIGS. 4b, 4c, and 4d shows an example methods, wherein the validity window of the reference configuration may be driven by UL or DL grants and the repetition level indicated. In example method 400b, a UE receives an UL grant (step 420) . In step 422, the UE determines whether the UL configuration of the grant is validated. If the UL configuration of the grant is validated, then at step 424 the UE assume the reference UL configuration for UL transmission. If the UL configuration of the grant is not validated, then at step 426, the UE uses the control reference configuration for UL transmission.

In example method 400c, a UE receives a DL grant at step 430. At step 432, the UE determines whether the DL configuration of the DL grant is indicated. If the DL configuration of the DL grant is indicated, then at step 434 the UE assumes that the DL reference configuration for receiving DL data is the DL configuration of the DL grant. If the DL configuration of the DL grant is not indicated, then at step 436 the UE may use the control reference configuration for the DL transmission.

In example 400d, the UE is monitoring for control data at step 440. In step 442, the UE assumes the control reference configuration for monitoring control data.

Data Scrambling

For HD-FDD (half-duplex frequency division duplex) , the data scrambling for NPDCCH (narrowband physical downlink control channel) and NPDSCH (Narrowband Physical Downlink Shared Channel) is often initialized at the start of every M transmission where M=4 for NPDCCH and M=min (N_rep, 4) for NPDSCH.

For NPDCCH, the scrambling sequence generation may limit itself to using the subframe index and cell ID, e.g.,:

And for NPDSCH, the scrambling sequence generation may be based on:

For TDD, with UL subffames in between NPDSCH and NPDCCH, the transmission duration over four transmission may be large.

So, if NPDCCH is transmitted on subframes {0, 4, 5, 9, 10, 14, 15, 19} , the scrambling of NPDCCH on subframes {0, 4, 5, 9} shall be based on SF#0 (subframe number 0) , and scrambling for NPDCCH on subframes {10, 14, 15, 19} is also based on SF#0 because SF#0 and SF#10 have same subframe index but are in a different frame index. Similarly, the same scrambling sequence may be used for repetition transmission of NPDSCH, but unfortunately such scrambling degrades inter-cell interference randomization because UE1 and UE2 may happen to receive the same information on a DL, and UE1 and UE2 may become confused, which is a problem with wireless systems today.

The same issue is also observed for NPUSCH (Narrowband Physical Uplink Shared Channel) where the scrambling sequence generator is initialized with

for every M transmission, (where M=1, 2 or 4) subframes dependent on the subcarrier spacing and repetition level for NPUSCH.

For half-duplex frequency division duplex (HD-FDD) , DMRS (Demodulation Reference Signal) sequence hopping can be configured for intercell interference randomization while the sequence is reinitialized at the beginning of each resource unit (which has a length of 8ms or 32ms dependent on subcarrier spacing) for single tone and every subframe for multiple tone. The sequence hopping pattern is given by

where ns is the slot number of the first slot of the resource unit.

For TDD, the number ofUL subframes per frame for some configurations is even. In such case, the same DMRS sequence is used for each RU transmission the sequence group hopping may be configured (e.g., indexed from 0 to 19) . In embodiments, the data scrambling for TDD (or the group hopping pattern) may be changed in order realize improvements to the wireless communication systems and methods.

For example, the scrambling sequence generation may use more LSBs (less significant bits) of the frame index n_f to avoid repeating the scrambling sequence. In such an example, the scrambling sequence may use mod (nf, 61) to replace mod (nf, 2) . Additionally and/or alternatively, The scrambling sequence generation may also be based on a block counter which is incremented by 1 for every M transmission. For example, the scrambling sequence generator may initialized with

Where

And i₀ is the absolute subffame number of the first transmission, N_abs is the total number of transmission subframes including all the repetitions, and M is the block size, e.g., M=min (Nrep, 2) for NPDSCH and NPUSCH and 4 for NPDCCH.

Such changes to the data scrambling helps prevent the inter-cell interference previously seen by systems and methods of wireless communications.

Those of skill in the art would understand 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 referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The functional blocks and modules described herein (e.g., the functional blocks and modules in FIG. 2) may comprise processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, etc., or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. Skilled artisans will also readily recognize that the order or combination of components, methods, or interactions that are described herein are merely examples and that the components, methods, or interactions of the various aspects of the present disclosure may be combined or performed in ways other than those illustrated and described herein.

The various illustrative logical blocks, modules, and circuits described in connection 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. A processor may also be implemented as a combination of computing devices, e.g., 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.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, 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 such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Computer-readable storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, a connection may be properly termed 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, or digital subscriber line (DSL) , then the coaxial cable, fiber optic cable, twisted pair, or DSL, are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , hard disk, solid state disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

As used herein, including in the claims, the term “and/or, ” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) or any of these in any combination thereof.

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 generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

A method of sending a special frame, the method comprising:

identifying a type of data being processed to be included in a downlink special subframe;

based on the determined type of data, deciding whether the downlink special subframe will be transmitted according to simple repetition or according to cyclic repetition; and

performing one of:

based on the decision that the downlink special subframe will be transmitted according to simple repetition, resource mapping the downlink special subframe using all available resource elements of allocated subframes;

based on the decision that the downlink special subframe will be transmitted according to cyclic repetition, resource mapping the downlink special subframe using one or more of puncturing and symbol level combining.
A method of uplink (UL) configuring, the method comprising:

receiving, via one or more antennas of a receiver of an user device (UE) , an UL grant;

determining whether the UL grant includes a validated UL configuration; and

performing one of:

based on a determination that the UL grant includes a validated UL configuration, sending an UL transmission according to the validated UL configuration; and

based on a determination that the UL grant does not includes a validated UL configuration, sending an UL transmission according control reference configuration information.
A method of downlink (DL) configuring, the method comprising:

receiving, via one or more antennas of a receiver of an user device (UE) , an DL grant;

determining whether the DL grant includes a validated DL configuration; and

performing one of:

based on a determination that the DL grant includes a validated DL configuration, sending an DL transmission according to the validated DL configuration; and

based on a deterrnination that the DL grant does not includes a validated DL configuration, sending an DL transmission according control reference configuration information.
A method of data scrambling comprising:

generating a data scrambling sequence using three or more less significant bits (LSBs) of the frame index to avoid inter-cell interference.
A method of data scrambling comprising:

using a block counter which is incremented by 1 for every M transmission;

the scrambling sequence generator performing:

wherein

wherein

and wherein i₀ is the absolute subframe number of a first transmission, N_abs is the total number of transmission subframes including all the repetitions, and M is a block size, wherein M=min (Nrep, 2) for NPDSCH and NPUSCH and 4 for NPDCCH.