CN108604964B - Self-contained TDD frame structure and DL-UL configuration in 5G systems - Google Patents

Abstract

Apparatus and methods for flexible UL/DL scheduling in a 5G system are generally described. The UE decodes the DL control information from the eNB. The control information indicates a specific UL/DL configuration including a ratio between UL and DL subframes, a position of the subframe, and a period of application for a configurable period that can be adjusted each time new control information is received. HARQ-ACK feedback is indicated in the last subframe, or in the earliest subframe (at least K subframes after the associated DL subframe), or evenly distributed over one or more subframes (at least K subframes after the associated DL subframe).

Description

Self-contained TDD frame structure and DL-UL configuration in 5G systems

Priority declaration

The present application claims priority from U.S. provisional patent application serial No. 62/302,020 entitled SELF-CONTAINED TDD FRAME STRUCTURE AND DL-UL CONFIGURATION IN 5G systems (SELF-CONTAINED TDD FRAME STRUCTURE AND DL-UL CONFIGURATION IN 5G system), filed on 3/1/2016, which is hereby incorporated by reference IN its entirety.

Technical Field

Embodiments relate to radio access networks. Some embodiments relate to providing data in cellular and Wireless Local Area Network (WLAN) networks, including third generation partnership project long term evolution (3GPP LTE) networks and LTE-advanced (LTE-a) networks, and 4 th generation (4G) networks and fifth generation (5G) networks. Some embodiments relate to Time Division Duplexing (TDD) in 5G networks.

Background

The use of 3GPP LTE systems, including LTE and LTE-advanced systems, has increased due to the increase in device types of User Equipment (UEs) that use network resources, as well as the increase in the amount of data and bandwidth used by various applications (e.g., video streams) operating on these UEs. Therefore, the 3GPP LTE system continues to be developed to improve access to information and data sharing using the next generation wireless communication system 5G. 5G desires to provide a unified network/system that is capable of meeting the vastly different and sometimes conflicting performance dimensions and services driven by different services and applications, while maintaining compatibility with legacy UEs and applications.

The increase in the number and types of UEs may help to maximize the flexibility of subframe design. In particular, when TDD is used for communication, it may be desirable for the UE to monitor and blindly decode most of the subframes. This may undesirably increase power consumption, which may be particularly important for Machine Type Communication (MTC) UEs with limited battery life, and false alarm rates between UEs.

Drawings

In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

Fig. 1 is a functional diagram of a wireless network according to some embodiments.

FIG. 2 illustrates components of a communication device according to some embodiments.

Fig. 3 illustrates a block diagram of a communication device, in accordance with some embodiments.

Fig. 4 illustrates another block diagram of a communication device in accordance with some embodiments.

Fig. 5 illustrates a frame structure supporting a variable Uplink (UL)/Downlink (DL) ratio configuration, in accordance with some embodiments.

Fig. 6 illustrates UL/DL configurations according to some embodiments.

Fig. 7 illustrates UL/DL configuration modifications according to some embodiments.

Fig. 8 illustrates a Physical Downlink Shared Channel (PDSCH) hybrid automatic repeat request (HARQ) timeline in accordance with some embodiments.

FIG. 9 illustrates a method of flexible communication, in accordance with some embodiments.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of others. Embodiments set forth in the claims encompass all available equivalents of those claims.

Fig. 1 illustrates an example of a portion of an end-to-end network architecture of a Long Term Evolution (LTE) network having various components of the network, in accordance with some embodiments. As used herein, LTE networks refer to LTE and LTE-advanced (LTE-a) networks, as well as other releases of LTE networks to be developed. Network 100 may include a Radio Access Network (RAN) (e.g., an E-UTRAN or evolved universal terrestrial radio access network as depicted) 101 and a core network 120 (e.g., shown as an Evolved Packet Core (EPC)) coupled together by an SI interface 115. For convenience and brevity, only a portion of the core network 120 and the RAN 101 are shown in this example.

The core network 120 may include a Mobility Management Entity (MME)122, a serving gateway (serving GW)124, and a packet data network gateway (PDN GW) 126. RAN 101 may include an evolved node b (enb)104 (which may serve as a base station) for communicating with User Equipment (UE) 102. The enbs 104 may include a macro eNB 104a and a Low Power (LP) eNB 104 b. The eNB 104 and the UE 102 may employ the techniques described herein.

The MME 122 may be similar in function to the control plane of a conventional Serving GPRS Support Node (SGSN). The MME 122 may manage mobility aspects in access, such as gateway selection and tracking area list management. The serving GW 124 may terminate (terminate) an interface towards the RAN 101 and route data packets between the RAN 101 and the core network 120. In addition, the serving GW 124 may be a local mobility anchor for inter-eNB handover and may also provide an anchor for inter-3 GPP mobility. Other responsibilities may include lawful interception, charging, and some policy enforcement. The serving GW 124 and MME 122 may be implemented in one physical node or in separate physical nodes.

The PDN GW 126 may terminate the SGi interface towards a Packet Data Network (PDN). The PDN GW 126 may route data packets between the EPC 120 and the external PDN, and may perform policy enforcement and charging data collection. The PDN GW 126 may also provide an anchor point for mobile devices with non-LTE access. The external PDN may be any type of IP network, as well as an IP Multimedia Subsystem (IMS) domain. The PDN GW 126 and the serving GW 124 may be implemented in one physical node or in separate physical nodes.

The enbs 104 (macro and micro enbs) may terminate the air interface protocol and may be the first contact point for the UE 102. In some embodiments, the eNB 104 may implement various logical functions of the RAN 101 including, but not limited to, RNCs (radio network controller functions), such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. According to an embodiment, the UE 102 may be configured to communicate Orthogonal Frequency Division Multiplexed (OFDM) communication signals with the eNB 104 over a multicarrier communication channel in accordance with an OFDMA communication technique. The OFDM signal may include a plurality of orthogonal subcarriers.

S1 interface 115 may be an interface separating RAN 101 and EPC 120. The S1 interface 115 may be divided into two parts: S1-U and S1-MME, where S1-U may carry traffic data between eNB 104 and serving GW 124, and S1-MME may be the signaling interface between eNB 104 and MME 122. The X2 interface may be an interface between enbs 104. The X2 interface may include two parts: X2-C and X2-U. X2-C may be a control plane interface between eNBs 104, while X2-U may be a user plane interface between eNBs 104.

With cellular networks, LP cell 104b may generally be used to extend coverage to indoor areas where outdoor signals do not reach well, or to increase network capacity in heavily used areas. In particular, it may be desirable to use different sized cells (macro, micro, pico, and femto cells) to enhance the coverage of a wireless communication system, thereby improving system performance. The different sized cells may operate on the same frequency band or may operate on different frequency bands (with each cell operating on a different frequency band or only different sized cells operating on different frequency bands). As used herein, the term LP eNB refers to any suitable opposing LP eNB for implementing a smaller cell (smaller than a macro cell), such as a femto cell, pico cell, or micro cell. A femto cell eNB may typically be provided by a mobile network operator to its residential or enterprise customers. Femto cells may typically be the size of a residential gateway or smaller and are typically connected to broadband lines. Femto cells may connect to the mobile operator's mobile network and provide additional coverage typically ranging from 30 meters to 50 meters. Thus, LP eNB 104b may be a femto cell eNB as it is coupled through PDN GW 126. Similarly, a pico cell may be a wireless communication system that typically covers a small area, e.g., in a building (office building, mall, train station, etc.), or more recently in an airplane. A picocell eNB may typically connect to another eNB, e.g., a macro eNB, through its Base Station Controller (BSC) functionality over an X2 link. Thus, because the LP eNB may be coupled to the macro eNB 104a via an X2 interface, the LP eNB may be implemented with a pico eNB. The pico eNB or other LP eNB 104b may contain some or all of the functionality of the macro eNB LP eNB 104 a. In some cases, this may be referred to as an access point base station or an enterprise femtocell.

Communications over an LTE network may be divided into 10ms radio frames, each of which may include 101 ms subframes. Each subframe in the frame may in turn comprise two 0.5ms slots. Each subframe may be used for Uplink (UL) communication from the UE 102 to the eNB 104 or Downlink (DL) communication from the eNB 104 to the UE. In one embodiment, the eNB 104 may allocate a greater number of DL communications than UL communications in a particular frame. The eNB 104 may schedule transmissions on multiple frequency bands. Each slot of a subframe may include 6-7 OFDM symbols, depending on the system used. In one embodiment, a subframe may include 12 subcarriers. However, in a 5G system, the frame size (ms) and the number of subframes within a frame may be different from those of a 4G or LTE system. The subframe size may also vary between frames in a 5G system. In some embodiments, the 5G system may span 5 times the frequency of the LTE/4G system, in which case the frame size of the 5G system may be 5 times smaller than the frame size of the LTE/4G system.

The downlink resource grid may be used for downlink transmissions from the eNB 104 to the UE 102, while the uplink resource grid may be used for uplink transmissions from the UE 102 to the eNB 104 or from the UE 102 to another UE 102. The resource grid may be a time-frequency grid, which is a physical resource in the downlink in each slot. The smallest time-frequency unit in the resource grid may be represented as a Resource Element (RE). Each column and each row of the resource grid may correspond to one OFDM symbol and one OFDM subcarrier, respectively. The resource grid may include Resource Blocks (RBs) that describe the mapping of physical channels to resource elements and physical RBs (prbs). A PRB may be the smallest resource unit that may be allocated to a UE. In some embodiments, an RB may be 180kHz wide in frequency and 1 slot long in time. In frequency, an RB may be 12x 15kHz subcarrier or 24x 7.5kHz subcarrier wide, depending on the system bandwidth. In a Frequency Division Duplex (FDD) system, both uplink and downlink frames may be 10ms and are frequency (full duplex) or time (half duplex) separated. In a TDD system, uplink and downlink subframes may be transmitted on the same frequency and multiplexed in the time domain. The duration of the resource grid 400 in the time domain corresponds to one subframe or two resource blocks. Each resource grid may include 12 (subcarriers) × 14 (symbols) ═ 168 resource elements.

Unlike FDD systems, TDD systems may include UL, DL, and special subframes due to the time division aspect of the system when switching between UL and DL subframes. In particular, the special subframe may be preceded by a DL subframe or a UL subframe (and may be followed by a subframe of the opposite type), and the special subframe may include UL and DL control regions. A guard period may be reserved at the beginning of the special subframe to allow the UE 102 to switch between the receiver chain and the transmitter chain.

Each OFDM symbol may include a Cyclic Prefix (CP), which may be used to effectively cancel inter-symbol interference (ISI), and a Fast Fourier Transform (FFT) period. The duration of the CP may be determined by the highest expected degree of delay spread. While distortion from the previous OFDM symbol may exist within the CP, the previous OFDM symbol does not enter the FFT period if the CP has sufficient duration. Once the FFT periodic signal is received and digitized, the receiver can ignore the signal in the CP.

There may be several different physical downlink channels transmitted using such resource blocks, including a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Shared Channel (PDSCH). Each downlink subframe may be divided into a PDCCH and a PDSCH. The PDCCH may typically occupy the first two symbols of each subframe and carry information about the transport format and resource allocation associated with the PDSCH channel and H-ARQ information about the uplink shared channel. The PDSCH may carry user data and higher layer signaling destined for the UE and occupy the remainder of the subframe. In general, downlink scheduling (allocation of control and shared channel resource blocks to UEs in a cell) may be performed at the eNB based on channel quality information provided to the eNB from the UEs, and then downlink resource allocation information may be transmitted to each UE on a PDCCH used for (allocated to) the UE. The PDCCH may include Downlink Control Information (DCI) in one of a plurality of formats that indicates to the UE how to find and decode data (transmitted on the PDSCH in the same subframe) from the resource grid. The DCI format may provide details such as the number of resource blocks, resource allocation type, modulation scheme, transport block, redundancy version, coding rate, and the like. Each DCI format may have a Cyclic Redundancy Code (CRC) and be scrambled with a Radio Network Temporary Identifier (RNTI) (which identifies the target UE for which the PDSCH is intended). Using UE-specific RNTIs may restrict decoding of DCI formats (and corresponding PDSCHs) to only the targeted UEs.

In addition to PDCCH, eNB 104 and UE 102 may use enhanced PDCCH (epdcch). Unlike PDCCH, EPDCCH may be arranged in resource blocks normally allocated to PDSCH. Different UEs may have different EPDCCH configurations configured by Radio Resource Control (RRC) signaling. Each UE 102 may be configured with multiple EPDCCH sets and the configuration may also be different between these sets. Each EPDCCH set may have 2, 4, or 8 PRB-pairs. In some embodiments, resource blocks configured for EPDCCH in a particular subframe may be used for PDSCH transmission if they are not used for EPDCCH transmission during the subframe.

To be able to retransmit lost or erroneous data, a hybrid automatic repeat request (HARQ) scheme may be used to provide feedback to the transmitter about the success or failure of a decoding attempt after each received data block. When eNB 104 transmits data to UE 102 in PDSCH (or 5G PDSCH, referred to as xPDSCH), data packets may be transmitted in PDCCH in the same subframe along with an indicator that informs UE 102 about the scheduling of PDSCH, including the time of transmission, and other scheduling information to transmit data. For each PDSCH codeword received by the UE 102, the UE 102 may respond with an ACK when the codeword is successfully decoded or a NACK when the codeword is not successfully decoded. The eNB 104 may expect the ACK/NACK feedback to be after a predetermined number of subframes from the subframe in which the PDSCH data is transmitted. Upon receiving a NACK from the UE 102, the eNB 104 may retransmit the transport block or skip retransmission when the number of retransmissions exceeds a maximum value. The UE may transmit ACK/NACK for the corresponding PDSCH four subframes after receiving the PDSCH from the eNB 104. The HARQ-ACK information corresponding to the PDSCH may include, for example, 1 or 2 information bits (DCI formats 1a and 1b, respectively), depending on the number of codewords present. The HARQ-ACK bits may then be processed according to the PUCCH.

The embodiments described herein may be implemented in a system using any suitably configured hardware and/or software. Fig. 2 illustrates components of a UE according to some embodiments. At least some of the components shown may be used in the UE 102 (or eNB 104) shown in fig. 1. The UE 200 and other components may be configured to use the synchronization signals described herein. The UE 200 may be one of the UEs 102 shown in fig. 1, and may be a fixed, non-mobile device, or may be a mobile device. In some embodiments, the UE 200 may include application circuitry 202, baseband circuitry 204, Radio Frequency (RF) circuitry 206, front-end module (FEM) circuitry 208, and one or more antennas 210 coupled together at least as shown. At least some of the baseband circuitry 204, RF circuitry 206, and FEM circuitry 208 may form a transceiver. In some embodiments, other network elements (e.g., enbs) may include some or all of the components shown in fig. 2. Other network elements (e.g., MME) may include an interface, such as an S1 interface, for communicating with the eNB over a wired connection with the UE.

The application or processing circuitry 202 may include one or more application processors. For example, the application circuitry 202 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, etc.). The processor may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system.

The baseband circuitry 204 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. Baseband circuitry 204 may include one or more baseband processors and/or control logic to process baseband signals received from the receive signal path of RF circuitry 206 and to generate baseband signals for the transmit signal path of RF circuitry 206. The baseband processing circuitry 204 may interface with the application circuitry 202 for the generation and processing of baseband signals and control the operation of the RF circuitry 206. For example, in some embodiments, the baseband circuitry 204 may include a second generation (2G) baseband processor 204a, a third (3G) baseband processor 204b, a fourth generation (4G) baseband processor 204c, and/or other baseband processor(s) 204d for other existing generations, generations in development, or generations to be developed in the future (e.g., fifth generation (5G), 5G, etc.). The baseband circuitry 204 (e.g., one or more of the baseband processors 204 a-d) may process various radio control functions that enable communication with one or more radio networks via the RF circuitry 206. The radio control functions may include, but are not limited to: signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, the modulation/demodulation circuitry of the baseband circuitry 204 may include FFT, precoding, and/or constellation mapping/demapping functionality. In some embodiments, the encoding/decoding circuitry of baseband circuitry 204 may include convolution, tail-biting convolution, turbo, Viterbi (Viterbi), and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functions are not limited to these examples, and other suitable functions may be included in other embodiments.

In some embodiments, the baseband circuitry 204 may include elements of a protocol stack, e.g., elements of an Evolved Universal Terrestrial Radio Access Network (EUTRAN) protocol, including, for example, Physical (PHY) elements, Medium Access Control (MAC) elements, Radio Link Control (RLC) elements, Packet Data Convergence Protocol (PDCP) elements, and/or Radio Resource Control (RRC) elements. A Central Processing Unit (CPU)204e of the baseband circuitry 204 may be configured to run elements of a protocol stack for signaling of the PHY, MAC, RLC, PDCP, and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio Digital Signal Processors (DSPs) 204 f. The audio DSP(s) 204f may be or include elements for compression/decompression and echo cancellation, and may include other suitable processing elements in other embodiments. In some embodiments, components of the baseband circuitry may be combined in a single chip or a single chipset, or arranged on the same circuit board, as appropriate. In some embodiments, some or all of the constituent components of the baseband circuitry 204 and the application circuitry 202 may be implemented together, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 204 may provide communications compatible with one or more radio technologies. For example, in some embodiments, baseband circuitry 204 may support communication with an Evolved Universal Terrestrial Radio Access Network (EUTRAN) and/or other Wireless Metropolitan Area Networks (WMANs), Wireless Local Area Networks (WLANs), Wireless Personal Area Networks (WPANs). Embodiments in which the baseband circuitry 204 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. In some embodiments, the device may be configured to operate in accordance with communication standards or other protocols or standards including Institute of Electrical and Electronics Engineers (IEEE)802.16 wireless technology (WiMax), IEEE 802.11 wireless technology (WiFi), including IEEE 802.11ad operating in the 60GHz millimeter wave spectrum, or various other wireless technologies such as global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE Radio Access Network (GERAN), Universal Mobile Telecommunications System (UMTS), UMTS Terrestrial Radio Access Network (UTRAN), or other 2G, 3G, 4G, 5G, etc. technologies that have been or will be developed.

The RF circuitry 206 may enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 206 may include switches, filters, amplifiers, and the like to facilitate communication with the wireless network. RF circuitry 206 may include a receive signal path that may include circuitry to down-convert RF signals received from FEM circuitry 208 and provide baseband signals to baseband circuitry 204. RF circuitry 206 may also include a transmit signal path that may include circuitry to up-convert baseband signals provided by baseband circuitry 204 and provide RF output signals to FEM circuitry 208 for transmission.

In some embodiments, RF circuitry 206 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 206 may include a mixer circuit 206a, an amplifier circuit 206b, and a filter circuit 206 c. The transmit signal path of the RF circuitry 206 may include filter circuitry 206c and mixer circuitry 206 a. RF circuitry 206 may also include synthesizer circuitry 206d, which synthesizer circuitry 206d is used to synthesize frequencies for use by mixer circuitry 206a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 206a of the receive signal path may be configured to down-convert the RF signal received from the FEM circuitry 208 based on the synthesized frequency provided by the synthesizer circuitry 206 d. The amplifier circuit 206b may be configured to amplify the downconverted signal, and the filter circuit 206c may be a Low Pass Filter (LPF) or a Band Pass Filter (BPF) configured to remove unwanted signals from the downconverted signal to generate an output baseband signal. The output baseband signal may be provided to baseband circuitry 204 for further processing. In some embodiments, the output baseband signal may be a zero frequency baseband signal, but this is not a requirement. In some embodiments, mixer circuit 206a of the receive signal path may comprise a passive mixer, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 206a of the transmit signal path may be configured to upconvert the input baseband signal based on a synthesis frequency provided by the synthesizer circuitry 206d to generate an RF output signal for the FEM circuitry 208. The baseband signal may be provided by the baseband circuitry 204 and may be filtered by the filter circuitry 206 c. The filter circuit 206c may include a Low Pass Filter (LPF), although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a of the transmit signal path may comprise two or more mixers and may be arranged for quadrature down-conversion and/or quadrature up-conversion, respectively. In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley (Hartley) image rejection). In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuit 206a of the receive signal path and the mixer circuit 206a of the transmit signal path may be configured for superheterodyne operation.

In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, RF circuitry 206 may include analog-to-digital converter (ADC) circuitry and digital-to-analog converter (DAC) circuitry, and baseband circuitry 204 may include a digital baseband interface to communicate with RF circuitry 206.

In some dual-mode embodiments, separate radio IC circuitry may be provided to process signals for each spectrum, although the scope of the embodiments is not limited in this respect.

In some embodiments, synthesizer circuit 206d may be a fractional-N synthesizer or a fractional-N/N +1 synthesizer, although the scope of embodiments is not limited in this respect as other types of frequency synthesizers may be appropriate. For example, synthesizer circuit 206d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase locked loop with a frequency divider.

The synthesizer circuit 206d may be configured to synthesize an output frequency based on the frequency input and the divider control input for use by the mixer circuit 206a of the RF circuit 206. In some embodiments, synthesizer circuit 206d may be a fractional-N/N +1 synthesizer.

In some embodiments, the frequency input may be provided by a Voltage Controlled Oscillator (VCO), but this is not required. The divider control input may be provided by the baseband circuitry 204 or the application processor 202 according to a desired output frequency. In some embodiments, the divider control input (e.g., N) may be determined from a look-up table based on the channel indicated by the application processor 202.

Synthesizer circuit 206d of RF circuit 206 may include a frequency divider, a Delay Locked Loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the divider may be a dual-mode divider (DMD) and the phase accumulator may be a Digital Phase Accumulator (DPA). In some embodiments, the DMD may be configured to divide an input signal by N or N +1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, a DLL may include a set of cascaded tunable delay elements, a phase detector, a charge pump, and a D-type flip-flop. In these embodiments, the delay elements may be configured to decompose the VCO period into Nd equal phase groups, where Nd is the number of delay elements in the delay line. In this manner, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuit 206d may be configured to generate a carrier frequency as the output frequency, while in other embodiments the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with a quadrature generator and divider circuit to generate multiple signals at the carrier frequency having multiple phases that are different from each other. In some embodiments, the output frequency may be the LO frequency (f)_LO). In some embodiments, the RF circuitry 206 may include an IQ/polarity converter.

FEM circuitry 208 may include a receive signal path that may include circuitry configured to operate on received RF signals from one or more antennas 210, amplify the received signals, and provide an amplified version of the received signals to RF circuitry 206 for further processing. FEM circuitry 208 may also include a transmit signal path, which may include circuitry configured to amplify signals provided by RF circuitry 206 for transmission by one or more of one or more antennas 210.

In some embodiments, FEM circuitry 208 may include TX/RX switches to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a Low Noise Amplifier (LNA) to amplify the received RF signal and provide the amplified received RF signal as an output (e.g., to the RF circuitry 206). The transmit signal path of FEM circuitry 208 may include a Power Amplifier (PA) to amplify an input RF signal (e.g., provided by RF circuitry 206), and may include one or more filters to generate an RF signal for subsequent transmission (e.g., by one or more of one or more antennas 210).

In some embodiments, the UE 200 may include additional elements, such as memory/storage, a display, a camera, sensors, and/or an input/output (I/O) interface, as described in more detail below. In some embodiments, the UE 200 described herein may be part of a portable wireless communication device, such as a Personal Digital Assistant (PDA), a laptop or portable computer with wireless communication capability, a network tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or another device that may receive and/or transmit information wirelessly. In some embodiments, the UE 200 may include one or more user interfaces designed to enable a user to interact with the system, and/or peripheral component interfaces designed to enable peripheral components to interact with the system. For example, the UE 200 may include one or more of a keyboard, keypad, touch pad, display, sensor, non-volatile memory port, Universal Serial Bus (USB) port, audio jack, power interface, one or more antennas, graphics processor, application processor, speaker, microphone, and other I/O components. The display may be an LCD or LED screen including a touch screen. The sensors may include a gyroscope sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may communicate with components of a positioning network, such as Global Positioning System (GPS) satellites.

Antenna 210 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, antennas 210 may be effectively separated to take advantage of different channel characteristics and spatial diversity that may result.

Although the UE 200 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including Digital Signal Processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Radio Frequency Integrated Circuits (RFICs), and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements.

Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device.

Fig. 3 is a block diagram of a communication device according to some embodiments. The device may be a UE or eNB (e.g., UE 102 or eNB 104 shown in fig. 1), which may be configured to track UEs as described herein. Physical layer circuitry 302 may perform various encoding and decoding functions, which may include forming a baseband signal for transmission and decoding a received signal. Communication device 300 may also include a medium access control layer (MAC) circuit 304 to control access to the wireless medium. The communication device 300 may also include processing circuitry 306 (e.g., one or more single-core or multi-core processors) and memory 308, the processing circuitry 306 and memory 308 arranged to perform the operations described herein. The physical layer circuitry 302, MAC circuitry 304, and processing circuitry 306 may handle various radio control functions that enable communication with one or more radio networks compatible with one or more radio technologies. The radio control functions may include signal modulation, encoding, decoding, radio frequency shifting, and the like. For example, similar to the device shown in fig. 2, in some embodiments, communication may be accomplished using one or more of WMAN, WLAN, and WPAN. In some embodiments, the communication device 300 may be configured to operate in accordance with 3GPP standards or other protocols or standards, including WiMax, WiFi, WiGig, GSM, EDGE, GERAN, UMTS, UTRAN, or other 2G, 3G, 4G, 5G, etc. technologies that have been or will be developed. The communication device 300 may include a transceiver circuit 312 for enabling wireless communication with other external devices and an interface 314 for enabling wired communication with other external devices. As another example, transceiver circuitry 312 may perform various transmit and receive functions, such as conversion of signals between a baseband range and a Radio Frequency (RF) range.

Antenna 301 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some MIMO embodiments, antennas 301 may be effectively separated to take advantage of different channel characteristics and spatial diversity that may result.

Although communication device 300 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements (e.g., processing elements including DSPs) and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, FPGAs, ASICs, RFICs, and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements. Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein.

Fig. 4 illustrates another block diagram of a communication device in accordance with some embodiments. In alternative embodiments, the communication device 400 may operate as a standalone device or may be connected (e.g., networked) to other communication devices. In a networked deployment, the communication device 400 may operate in the server-client network environment with the identity of a server communication device, a client communication device, or both. In an example, the communications device 400 can operate as a peer to peer communications device in a peer to peer (P2P) (or other distributed) network environment. The communication device 400 may be a UE, eNB, PC, tablet PC, STB, PDA, mobile phone, smartphone, network device, network router, switch or bridge, or any communication device capable of executing instructions (sequential or otherwise) that specify actions to be taken by the communication device. Further, while only a single communication device is shown, the term "communication device" should also be taken to include any collection of communication devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methods discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.

Examples as described herein may include, or may operate on, logic or multiple components, modules, or mechanisms. A module is a tangible entity (e.g., hardware) capable of performing specified operations and may be configured or arranged in a particular manner. In an example, the circuitry may be arranged as a module in a specified manner (e.g., internally or with respect to an external entity such as other circuitry). In an example, all or portions of one or more computer systems (e.g., a stand-alone client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application portions, or applications) to operate to perform modules of specified operations. In an example, the software may reside on a communication device readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

Thus, the term "module" is understood to encompass a tangible entity, i.e., an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., temporarily) configured (e.g., programmed) to operate in a specific manner or to perform some or all of any of the operations described herein. Considering the example where modules are temporarily configured, not every module need be instantiated at any given time. For example, where the modules include a general purpose hardware processor configured using software, the general purpose hardware processor may be configured at different times as respective different modules. The software may thus configure the hardware processor to, for example, constitute a particular module at a certain instance in time and to constitute a different module at a different instance in time.

A communication device (e.g., computer system) 400 may include a hardware processor 402 (e.g., a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a hardware processor core, or any combination thereof), a main memory 404, and a static memory 406, some or all of which may communicate with each other via an interlink (e.g., bus) 408. The communication device 400 may also include a display unit 410, an alphanumeric input device 412 (e.g., a keyboard), and a User Interface (UI) navigation device 414 (e.g., a mouse). In an example, the display unit 410, the input device 412, and the UI navigation device 414 may be a touch screen display. The communication device 400 may also include a storage device (e.g., drive unit) 416, a signal generation device 418 (e.g., a speaker), a network interface device 420, and one or more sensors 421, such as a Global Positioning System (GPS) sensor, compass, accelerometer, or other sensor. The communication device 400 may include an output controller 428, such as a serial (e.g., Universal Serial Bus (USB)), parallel, or other wired or wireless (e.g., Infrared (IR), Near Field Communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., printer, card reader, etc.).

The storage device 416 may include a communication device-readable medium 422 having stored thereon one or more sets of data structures or instructions 424 (e.g., software), the one or more sets of data structures or instructions 424 embodying or being utilized by any one or more of the techniques or functions described herein. The instructions 424 may also reside, completely or at least partially, within the main memory 404, within static memory 406, or within the hardware processor 402 during execution thereof by the communication device 400. In an example, one or any combination of the hardware processor 402, the main memory 404, the static memory 406, or the storage device 416 may constitute communication device readable media.

While the communication device-readable medium 422 is shown to be a single medium, the term "communication device-readable medium" can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 424.

The term "communication device-readable medium" can include any medium that can store, encode, or carry instructions for execution by communication device 400 and that cause communication device 400 to perform any one or more of the techniques of this disclosure, or that can store, encode, or carry data structures used by or associated with such instructions. Non-limiting examples of communication device readable media may include solid state memory, as well as optical and magnetic media. Specific examples of the communication device readable medium may include: non-volatile memories, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, e.g., internal hard disks and removable disks; magneto-optical disks; random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, the communication device readable medium may include a non-transitory communication device readable medium. In some examples, the communication device readable medium may include a communication device readable medium that is not a transitory propagating signal.

The transmission medium may also be used to send or receive instructions 424 over a communication network 426 via the network interface device 420 utilizing any one of a number of transmission protocols (e.g., frame relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), hypertext transfer protocol (HTTP), etc.). An example communication network may include: local Area Networks (LANs), Wide Area Networks (WANs), packet data networks (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., referred to as

Of the Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards, referred to as

IEEE 802.16 family of standards), IEEE 802.15.4 family of standards, Long Term Evolution (LTE) family of standards, Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, and so forth. In an example, the network interface device 420 may include one or more physical jacks (e.g., ethernet, coaxial, or telephone jacks) or one or more antennas to connect to the communication network 426. In an example, the network interface device 420 may include multiple antennas to wirelessly communicate using at least one of: single Input Multiple Output (SIMO), MIMO, or Multiple Input Single Output (MISO) techniques. In some examples, the network interface device 420 may communicate wirelessly using multi-user MIMO techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 400, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

As mentioned above, 5G systems may be FDD or TDD based. In some embodiments, the LTE system may reserve only a limited number of subframes within each radio frame as DL subframes or UL subframes, while the remaining subframes may be allocated as flexible subframes. The flexible subframes may be DL subframes or UL subframes, depending on the configuration used. To maintain maximum scheduling flexibility, instead of providing a specific configuration, the UE may simply assume that all subframes are flexible subframes (and thus may by default be used as DL subframes or as UL subframes when scheduled) -except for a small number of fixed UL subframes used for random access procedures. In this case, the UE may monitor all DL subframes and flexible subframes and blindly decode the control channel to determine, for example, whether the UE is being paged using the subframes. This may increase power consumption because the UE may decode the 5G physical downlink control channel (xPDCCH) in each flexible DL subframe. Note that although both PDCCH and xPDCCH are used for transmission of DL control information, the physical structure may be different. This may include, for example, mapping to physical resources (e.g., which REs to use, whether signals are beamformed), what type of information is encoded in the corresponding DCI. Furthermore, if the UE does not detect UL grant for a flexible subframe for a considerable time, the UE may assume that the subframe is a DL subframe and thus may blindly decode xPDCCH in the UL subframe, thereby increasing a false alarm rate.

To reduce power consumption at the UE without sacrificing UL/DL resource scheduling flexibility, certain elements in the 5G system may be considered. It is desirable to design the UL/DL configuration to support finer UL/DL ratio granularity while maximizing resource efficiency. To achieve this, in various embodiments, multiple UL/DL configurations may be used to support various UL/DL ratios. It is also desirable to dynamically signal the UL/DL configuration while minimizing control signaling overhead. To achieve this, in some embodiments, detailed signaling design mechanisms may implement dynamic UL/DL adaptation to achieve two goals: maximizing spectral efficiency and minimizing power consumption at the UE. It is also desirable to determine a detailed HARQ-ACK timeline for UL/DL configuration to guarantee Uplink Control Information (UCI) performance. To achieve this, in various embodiments, different HARQ timelines for data transmission for different use cases and requirements may be used.

To achieve the above object, a 5G system in which TDD communication is used may be designed in which a 5G transmission frame different from a typical LTE radio frame is used. In particular, the 5G transmission frame may have a different period than that of the LTE radio frame. Although the 5G transmission frame may include a plurality of 5G subframes, the number of 5G subframes within the 5G transmission frame may be the same as or different from the number of subframes in the LTE radio frame.

Fig. 5 illustrates a frame structure supporting a variable UL/DL ratio configuration according to some embodiments. Although 5G transmission frame i 502 and 5G transmission frame i + 1502 are shown, for convenience, only the details of 5G subframe 504 of one 5G transmission frame of the plurality of 5G transmission frames 502 are shown. Similarly, for convenience, only a limited number of 5G subframes 504 of 5G transmission frame i 502 are shown.

In particular, the 5G transmission frame 502 may employ one of a plurality of UL/DL configurations that specify the number and proportion of UL and DL subframes 504 within each 5G transmission frame 502. The UL/DL configuration may indicate the number of DL and UL transition periods within a particular period, which may include one or more 5G transmission frames 502. In some embodiments, two UL/DL configurations may be used, while in other embodiments, a greater number of configurations may be used. For example, 5G transmission frame 502 may have UL/DL configuration a 506, which UL/DL configuration a 506 may include two DL transmission periods 510, 516 and two UL transmission periods 514, 518, or 5G transmission frame 502 may have UL/DL configuration B508, which UL/DL configuration B508 may include two DL transmission periods 512, 516 and one UL transmission period 518.

In some embodiments, the duration of each 5G transmission frame 502 may remain the same. In such embodiments, the duration of the transmission periods (whether UL or DL) may vary between configurations, but the sum of the durations of all transmission periods may remain as the duration of the 5G transmission frame 502. Each UL or DL transmission period may include a plurality of consecutive UL or DL 5G subframes 504, respectively. Each 5G subframe 504 may have the same predetermined duration, which may be 0.2ms, for example. Thus, while the number of DL and UL 5G subframes 504 may vary, the total number of 5G subframes 504 may remain constant independent of the configuration used.

In a configuration with multiple DL transmission periods, the number of DL 5G subframes 504 may be different in one or more DL transmission periods; similarly, in a configuration with multiple UL transmission periods, the number of UL 5G subframes 504 may be different in one or more DL transmission periods. In other embodiments, the number of 5G subframes 504 may remain the same for each UL and/or DL transmission period, and may be the same or different between different types (UL/DL) of transmission periods. For example, as shown in UL/DL configuration a 506 of fig. 5, the first DL transmission period 510 has the same number of DL 5G subframes 504 as the UL 5G subframes 504 of the second UL transmission period 518 and a greater number of DL 5G subframes 504 than the UL 5G subframes 504 of the first UL transmission period 514, while the second DL transmission period 516 has the same number of DL 5G subframes 504 as the UL 5G subframes 504 of the first UL transmission period 514 and fewer DL 5G subframes 504 than the UL 5G subframes 504 of the second UL transmission period 518 (and thus fewer DL 5G subframes 504 than the first DL transmission period 510). As shown in UL/DL configuration B508 of fig. 5, the first DL transmission period 512 has a greater number of DL 5G subframes 504 than the second DL transmission period 516 or than the UL 5G subframes 504 of the UL transmission period 518, while the second DL transmission period 516 has fewer DL 5G subframes 504 than the UL 5G subframes 504 of the UL transmission period 518 (and thus fewer DL 5G subframes 504 than the first DL transmission period 512).

Guard periods (not shown in fig. 5) may be inserted to account for the time the UE uses to activate and deactivate the transmitter and receiver, as well as to account for radio propagation delays. Thus, the guard period may differ according to the activation/deactivation time of the physical components of the transmit and receive chains in the UE.

Fig. 6 illustrates UL/DL configurations according to some embodiments. More or fewer UL/DL configurations than shown may be used. Furthermore, in other embodiments, the particular UL/DL configuration may be different from that shown in fig. 6. As shown, the ratio of DL transmission periods to UL transmission periods in each 5G transmission frame (which may be, for example, 1ms or 2ms) may be independently adjusted to support applications with various traffic patterns, from symmetric (configurations 0-3) to highly asymmetric (configurations 4-7). Thus, in some embodiments, the UE may indicate to the eNB a desired mode or one or more applications that the eNB may then use to allocate a particular UL/DL configuration. Note that there may be at least one UL subframe and at least one DL subframe in each configuration. In this way, various applications can be efficiently supported using a single Component Carrier (CC). In some embodiments, when carrier aggregation is used, multiple CCs may be used to increase capacity, or to increase more flexibility, where different configurations may be used for each CC (i.e., the UL/DL configuration for each CC may be independent of each other CC).

In one embodiment, each 5G transmission frame of length X ms (e.g., 2ms) may include two half-frames of length X/2ms each. Each field may include N subframes of length X/2N ms (e.g., 0.2ms when N is 10). In TDD UL-DL configurations 0-3, two guard periods may be used (when switching from DL subframe to UL subframe); however, in configurations 4-7, only one GP is used. UL-DL configurations with X/2ms and X ms DL-to-UL switch-point periods may be supported.

In the embodiment shown in fig. 6, each half frame may include five subframes. To support different applications from symmetric services to highly asymmetric services, the ten subframes within each 5G transmission frame shown in fig. 6 may be configured in different configurations to eight different DL and UL ratios (8:2, 6:4, 4:6, 2:8, 9:1, 7:3, 5:5, and 1: 9). The frame structure allows for fast feedback between the UE and its eNB and enables the adaptive frame structure system to more efficiently use other advanced techniques such as link adaptation, hybrid ARQ, beamforming, and transmit diversity.

As shown in fig. 6, in each configuration, each 5G transmission frame may include one or more predefined DL subframes. The eNB may broadcast the ratio of UL/DL configurations during any number of these DL subframes. This configuration may be maintained for a configurable period of one or more 5G transmission frames to reduce overhead and increase overall system spectral efficiency. Fig. 7 illustrates UL/DL configuration modifications according to some embodiments. In some embodiments, the DL subframe(s) 704 (during which the eNB broadcasts the configuration) may be at the beginning of a configurable period (also referred to as a modification period 702). Thus, the duration of the modification period 702 may be fixed.

As shown in fig. 7, some modification periods 702 may have a dedicated DL subframe 704, which dedicated DL subframe 704 is reserved for eNB signaling UL/DL configuration. In other cases, multiple modification periods 702 may share the use of the same DL subframe(s) 704 used to signal the UL/DL configuration to reduce overhead and increase overall system spectral efficiency. In one embodiment, the period for applying the UL/DL configuration broadcast in the fixed DL subframe(s) may be signaled using the dedicated information element(s) (IEs) of the DCI format transmitted in the dedicated DL subframe(s) 704. In some embodiments, the modification period 702 may be a single frame, while in other embodiments, the modification period 702 may include multiple frames.

In another embodiment, instead of using fixed DL subframe(s), the use of the uplink transmission period may be controlled in whole or in part by the eNB and the scheduling information carried in the DL DCI format for the PUSCH grant. The number and duration of each DL and UL period in fig. 5 may be different across 5G transmission frames. For example, one 5G transmission frame may be reconfigured to a different UL/DL ratio by dynamically scheduling some subframes from DL in 5G transmission frame i to UL in 5G transmission frame i +1 using one or more DCI formats for UL grants when the traffic pattern changes.

As shown in fig. 6, in each configuration, each 5G transmission frame may include one or more fixed special UL subframes. During a special UL subframe, the UE may send a hybrid automatic repeat request (HARQ) acknowledgement (HARQ-ACK) in response to a previous DL transmission arriving at the UE. Further, during special UL subframes, the UE may perform functions such as random access procedures, channel sounding, to assist CSI feedback for DL scheduling or for advanced MIMO techniques, and to facilitate other radio functions. Special UL subframes may be coordinated across neighboring cells, e.g., in coordinated multipoint system (CoMP), to improve UL control channel performance and simultaneously avoid cross-linking interference between multiple cells.

Various schemes may be used to design the HARQ-ACK timeline for PDSCH transmissions. Fig. 8 illustrates a PDSCH hybrid automatic repeat request (HARQ) timeline in accordance with some embodiments. Fig. 8 shows A5G transmission frame 800, the configuration of the 5G transmission frame 800 being similar to the UL/DL configuration a 506 in fig. 5. The frame 800 includes a plurality of DL data transmission periods 802, 804 and UL data transmission periods 806. As described above, each transmission period 802, 804, 806 may include multiple subframes. A unified HARQ-ACK timeline may be designed for all UL/DL ratio configurations in fig. 6, with variations depending on the particular emphasis.

In one embodiment (scenario 1), HARQ-ACK feedback for DL subframes in the first DL transmission period 802 of the 5G transmission frame 800 may be transmitted in the UL data transmission period 806. Specifically, in some embodiments, the HARQ-ACK feedback may be sent in the last UL subframe 808 of the UL data transmission period 806. This may provide a predetermined amount of delay between DL transmission and HARQ-ACK feedback. The final UL subframe 808 of the UL data transmission period 806 may include a PUSCH in which UL data is transmitted, and also include UCI. In addition to including HARQ-ACKs, UCI may include one or both of SR (scheduling request) and Channel Quality Indicator (CQI). In one embodiment, the HARQ-ACK feedback for the DL subframes in the first DL transmission period 802 of the 5G transmission frame 800 may be sent in the UL data transmission period 806, i.e., the HARQ-ACK feedback may be sent in the same 5G transmission frame 800 as the received communication.

In other embodiments, the HARQ-ACK feedback may occur in a different UL subframe in the UL data transmission period than the last UL subframe. UL subframes for including HARQ-ACK feedback may be provided in RRC or other higher layer signaling. In other embodiments where there are multiple UL data transmission periods, the HARQ-ACK feedback may occur in the last (or another) subframe in the last or another UL data transmission period. As described above, the location of the UL subframe (and UL data transmission period) for including HARQ-ACK feedback may be provided in RRC or other higher layer signaling.

Whether a particular configuration includes a single UL data transmission period or multiple UL data transmission periods, another scheme (scheme 2) may desire to minimize HARQ-ACK feedback delay. To minimize this delay, in some embodiments, HARQ-ACK feedback for a given DL subframe (subframe n) may be transmitted in the earliest UL subframe after subframe n + K (i.e., K subframes away from the DL subframe). K may be fixed in the IEEE specification or may be provided in RRC or other higher layer signaling. For example, K may be 4 or 5 subframes.

Instead of emphasizing minimizing HARQ-ACK feedback delay, other embodiments may focus on providing maximum scheduling flexibility for the eNB (scheme 3). In such embodiments, the HARQ-ACK payload may be distributed as evenly as possible over the available UL subframes in an attempt to avoid restricting the eNB's xPUSCH scheduling.

Thus, the various embodiments described above focus on fixed subframe locations, minimizing delay, or maximizing scheduling flexibility. Details of these embodiments are described below using tables 1-3. These tables may show embodiments where xPDSCH transmissions exist with corresponding xpdcchs detected within subframe(s) n-K, where K ≧ 5, K ∈ K, and K is defined in tables 1-3 for different schemes to achieve various goals. The 5 subframes may be chosen as the minimum value (k ═ 4) so that there is enough time for the UE to decode xPDCCH. Each of tables 1-3 shows K for the UL/DL configuration shown in fig. 6, where the number of subframes, N, is 10.

Table 1: scheme 1 Downlink Association set index K: { K₀,k₁,…,k_M-1}

In table 1, the last UL subframe may include HARQ-ACK feedback. Thus, for example, in UL/DL configuration 0, where subframes 0-3 and 5-8 are DL subframes and only subframes 4 and 9 are UL subframes, K may take on the value 6-9 (since K is greater than 4), which corresponds to the previous DL subframes 0-3 (in subframe 4) and 5-8 (in subframe 9), which are located in the previous frame. Note that in any case, K does not take the value 5, since 5 subframes before subframe 4 or 9 correspond to UL subframes instead of DL subframes. In UL/DL configuration 3, where only subframes 0 and 5 are DL subframes and subframes 1-4 and 6-9 are UL subframes, K may be limited to a value of 9, which corresponds to prior DL subframe 0 (in subframe 4) and prior DL subframe 5 (in subframe 9). In UL/DL configuration 4, where subframes 0-8 are DL subframes and subframe 9 is a UL subframe, K may take values of 5-9 and 11-14, which correspond to DL subframes 0-4 and preceding DL subframes 5-8 in the current subframe, where K ═ 10 is not available because it corresponds to UL subframe 9 in the preceding frame.

Table 2: scheme 2 Downlink Association set index K: { K₀,k₁,…,k_M-1}

In table 2, the first UL subframe may include HARQ-ACK feedback. The value of K in each configuration is similar to that in table 1, but occurs in different subframes, thus generally taking slightly different values. For example, in UL/ DL configurations 0 and 4, the K value may occur in the same subframe and take one of the same available values as in table 1. However, in UL/DL configuration 6, instead of K taking on values of 5-9 only in UL subframe 9, each of UL subframes 6-9 may take on values of only 5, which corresponds to subframes 0-4 of the same frame.

Table 3: scheme 3 Downlink Association set index K: { K₀,k₁,…,k_M-1}

In table 3, the HARQ-ACK feedback is distributed as evenly as possible in the UL subframe. Thus, for example, when multiple UL subframes are available to provide HARQ-ACK feedback for multiple DL subframes, the HARQ-ACK feedback is spread out to maximize the number of UL subframes used. Thus, for example, in UL/DL configuration 1, only two UL subframes (e.g., 8 and 9) may be used to provide HARQ-ACK feedback for three DL subframes (e.g., 0-2), thus each UL subframe provides HARQ-ACK feedback for at least one DL subframe. In UL/DL configuration 2, only three UL subframes (e.g., 7-9) may be used to provide HARQ-ACK feedback for two DL subframes (e.g., 0-1), so two of the three UL subframes provide HARQ-ACK feedback for one DL subframe and one UL subframe is not used to provide HARQ-ACK feedback. In UL/DL configuration 6, with 5 UL subframes and 5 DL subframes, each UL subframe (5-9) provides HARQ-ACK feedback for a respective DL subframe (e.g., 0-4).

FIG. 9 illustrates a method of flexible communication, in accordance with some embodiments. The method may be performed by any of the UEs shown and described in fig. 1-4. Accordingly, embodiments of the method may include additional or fewer operations or processes than those shown in fig. 9. Furthermore, embodiments of the method are not necessarily limited to the temporal order shown in FIG. 9. The methods may be practiced with appropriate systems, interfaces, and components. Further, while the methods and other methods described herein may relate to UEs operating in accordance with 3GPP or other standards, embodiments of those methods are not limited to only those UEs and may also be practiced by other communication devices.

At operation 902, the UE may receive TDD control information. TDD control information may be provided by an eNB and, in some embodiments, may be coordinated with multiple cells. For example, the TDD control information may be received in a SIB or in a predetermined DL subframe. In the latter case, the TDD control information may be indicated by a DCI format carried by the xPDCCH. The DCI format may be modified from a 4G DCI format, or may be a completely new DCI format. In some embodiments, the predetermined DL subframe may be a first subframe in a configurable period. The configurable time period may be adjusted each time the UE receives new TDD control information.

At operation 904, the UE may decode the TDD control information and determine a DL/UL configuration. The predetermined DL subframe may be reserved for signaling UL/DL configuration. The predetermined DL subframe may be associated with consecutive frames such that a plurality of consecutive frames share the UL/DL configuration indicated by the predefined DL subframe. The configurable period to which the UL/DL configuration is applicable may be indicated by a dedicated information element. The DL and UL configurations may indicate a ratio between UL subframes and DL subframes and placement of UL subframes and DL subframes for a configurable period.

Once the UL/DL configuration is determined at operation 904, the UE may communicate with the eNB at operation 906. This may include receiving control and data from the eNB in a DL subframe indicated by the UL/DL configuration, and transmitting or scheduling transmissions to the eNB in a UL subframe indicated by the UL/DL configuration. The UL/DL configuration may include a transmission frame including a plurality of DL transmission periods and at least one UL transmission period. Each DL transmission period and UL transmission period may include a plurality of DL subframes and UL subframes, respectively.

At operation 908, the UE may receive data from the eNB in at least one DL subframe and then send HARQ-ACK feedback to the eNB as indicated by the TDD control information. HARQ-ACK feedback may be sent in a fixed UL subframe that is independent of which DL subframe of the frame the data is received in. In one embodiment, the fixed UL subframe may be the final UL subframe in the frame. In other embodiments, the UL subframes may vary from DL subframe to DL subframe. For example, the earliest UL subframe after a certain delay (e.g., 4 or 5 subframes, which may be set by the 5G specification) may be used to allow a UE to decode a DL subframe and determine that the data is for the UE. Alternatively, a set of UL subframes may be used over which HARQ-ACK feedback is distributed as evenly as possible.

At operation 910, the UE may determine whether the configurable period has ended and thus is time to receive a new UL/DL configuration with another configured period. If so, the UE may return to operation 902 where new TDD control information is received. The ratio of DL subframes to UL subframes in the new UL/DL configuration may depend on feedback from the UE regarding the type of running applications (where some applications require a greater number of DL subframes than UL subframes, and other applications require a greater number of UL subframes than DL subframes). This information may be provided to the eNB in a dedicated UL subframe so that the eNB may adjust the UL/DL configuration in a subsequent configurable period. If not, the UE may continue to communicate with the eNB in the next frame using the same UL/DL configuration at operation 906.

Although embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments shown are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

Such embodiments of the subject matter may be referred to herein, individually and/or collectively, by the term "embodiment" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept (in which case more than one is in fact disclosed). Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

In this document, the term "a" or "an" is used to include one or more, independently of any other instances or uses of "at least one" or "one or more," as is common in patent documents. In this document, the term "or" is used to refer to the nonexclusive, or "a or B" includes "a but not B," "B but not a," and "a and B," unless otherwise indicated. In this document, the terms "comprising" and "wherein" are used as the plain-english equivalents of the respective terms "comprising" and "wherein". Furthermore, in the following claims, the terms "comprising" and "including" are open-ended; that is, a system, UE, object, composition, formulation, or process that includes elements other than those listed after such term in a claim is still considered to fall within the scope of that claim. Furthermore, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

The abstract of the present disclosure is provided to comply with 37c.f.r. section 1.72(b) requirements for an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. The abstract is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. Furthermore, in the foregoing detailed description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims (31)

1. An apparatus for communication, comprising:

at least one processor configured to cause a user equipment, UE, to:

decoding downlink DL control information from a base station, the DL control information indicating a particular uplink UL/DL configuration selected from a set of predetermined UL/DL configurations for a configurable period of time; and

communicate with the base station based on the particular UL/DL configuration for the configurable period,

wherein the configurable period for the UL/DL configuration is indicated by the DL control information and the configurable period is different from a previous configurable period.

2. The apparatus of claim 1, wherein:

the DL control information is encoded in a system information block SIB.

3. The apparatus of claim 1, wherein:

the DL control information is encoded in a downlink control information DCI format carried by a fifth generation 5G physical downlink control channel, xPDCCH.

4. The apparatus of claim 1 or 2, wherein:

each frame comprises a predefined number of DL subframes at the beginning of the configurable period, and

the DL control information is received during the predefined number of DL subframes.

5. The apparatus of claim 1 or 2, wherein the at least one processor is further configured to determine that the UL/DL configuration for the configurable period is the same as the UL/DL configuration indicated by the DL control information.

6. The apparatus of claim 1 or 2, wherein:

the DL control information is received during predefined DL subframes reserved for signaling the UL/DL configuration, and

the predefined DL subframe is associated with a plurality of consecutive frames and is arranged in one of the plurality of consecutive frames such that the plurality of consecutive frames share the UL/DL configuration indicated by the predefined DL subframe.

7. The apparatus of claim 6, wherein:

the period for applying the UL/DL configuration indicated by the predefined DL subframe is signaled by using a dedicated information element, IE, of a DCI format.

8. The apparatus of claim 1 or 2, wherein:

the UL scheduling information is carried in a DL Downlink control information DCI format for a 5G physical uplink shared channel, xUSCH, grant, and

the UL/DL configuration between frames is independent and based on the UL scheduling information such that one of the following results:

a predetermined UL subframe in a previous frame is changed to a DL subframe in a current frame, an

A predetermined DL subframe in the previous frame is changed to an UL subframe in the current frame.

9. The apparatus of claim 1 or 2, wherein the at least one processor comprises a baseband processor configured to:

generating a hybrid automatic repeat request, HARQ, acknowledgement, HARQ-ACK in at least one UL subframe at a time indicated by the DL control information for a plurality of DL subframes depending on the UL/DL configuration.

10. The apparatus of claim 9, wherein:

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the at least one processor is further configured to generate HARQ-ACK feedback for a DL subframe in a first DL transmission period of the DL transmission periods and at least one of the DL subframes in the DL transmission periods of a previous transmission frame for transmission on a last UL subframe in the transmission frame.

11. The apparatus of claim 9, wherein:

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the at least one processor is further configured to generate HARQ-ACK feedback for a particular DL subframe in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on an earliest UL subframe in the transmission frame, the earliest UL subframe being at least K subframes from the particular DL subframe, where K is fixed by a specification.

12. The apparatus of claim 9, wherein:

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the at least one processor is further configured to generate HARQ-ACK feedback for DL subframes in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on one or more UL subframes in the transmission frame, each UL subframe being at least K subframes after the DL subframe associated with the HARQ-ACK feedback, where K is fixed by a specification, and the HARQ-ACK feedback being distributed as evenly as possible over the one or more UL subframes.

13. An apparatus for communication, comprising:

at least one processor configured to cause a base station to:

generating DL control information for transmission to a User Equipment (UE) in a predetermined Downlink (DL) subframe of a configurable period, the DL control information indicating a particular UL/DL configuration selected from a set of predetermined uplink (UL/DL) configurations for the configurable period; and

communicate with the UE based on the particular UL/DL configuration for the configurable period of time,

wherein the configurable period for the UL/DL configuration is indicated by the DL control information and the configurable period is different from a previous configurable period.

14. The apparatus of claim 13, wherein:

the DL control information generated by the at least one processor includes a configurable period independent of a previous configurable period.

15. The apparatus of claim 13 or 14, wherein:

the period for applying the UL/DL configuration indicated by the predetermined DL subframe is signaled in a dedicated information element, IE, of a DCI format.

16. The apparatus of claim 13 or 14, wherein:

the UL scheduling information is carried in a DL Downlink control information DCI format for a 5G physical uplink shared channel, xUSCH, grant, and

the UL/DL configuration between frames is independent and based on the UL scheduling information such that one of the following results:

a predetermined UL subframe in a previous frame is changed to a DL subframe in a current frame, an

A predetermined DL subframe in the previous frame is changed to an UL subframe in the current frame.

17. The apparatus of claim 13 or 14, wherein the at least one processor is further configured to:

decoding hybrid automatic repeat request, HARQ, acknowledgement, HARQ-ACK in at least one UL subframe at a time indicated by the DL control information for a plurality of DL subframes depending on UL/DL configuration.

18. The apparatus of claim 17, wherein:

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the at least one processor is further configured to decode HARQ-ACK feedback for a DL subframe in a first DL transmission period of the DL transmission periods and at least one of the DL subframes in the DL transmission periods of a previous transmission frame for transmission on a last UL subframe in the transmission frame.

19. The apparatus of claim 17, wherein:

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the at least one processor is further configured to decode HARQ-ACK feedback for a particular DL subframe in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on an earliest UL subframe in the transmission frame, the earliest UL subframe being at least K subframes from the particular DL subframe, where K is fixed by a specification.

20. The apparatus of claim 17, wherein:

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the at least one processor is further configured to generate HARQ-ACK feedback for DL subframes in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on one or more UL subframes in the transmission frame, each UL subframe being at least K subframes after the DL subframe associated with the HARQ-ACK feedback, where K is fixed by a specification, and the HARQ-ACK feedback being distributed as evenly as possible over the one or more UL subframes.

21. The apparatus of claim 13 or 14, wherein:

the DL control information is encoded in a system information block SIB or in a downlink control information DCI format carried by a fifth generation 5G physical downlink control channel, xPDCCH.

22. An apparatus of a User Equipment (UE), the apparatus comprising:

means for decoding downlink, DL, control information from a base station, the DL control information indicating a particular UL/DL configuration selected from a set of predetermined uplink UL/DL configurations; and

means for communicating with the base station based on the particular UL/DL configuration for a configurable period of time,

wherein the configurable period for the UL/DL configuration is indicated by the DL control information and the configurable period is different from a previous configurable period.

23. The apparatus of claim 22, wherein:

the DL control information is received during predefined DL subframes reserved for signaling UL/DL configuration,

the predefined DL subframe is associated with a plurality of consecutive frames and is arranged in one of the plurality of consecutive frames such that the plurality of consecutive frames share the UL/DL configuration indicated by the predefined DL subframe, and

the period for applying the UL/DL configuration indicated by the predefined DL subframe is signaled by using a dedicated information element, IE, of a DCI format.

24. The apparatus of claim 22 or 23, wherein:

the UL scheduling information is carried in a DL Downlink control information DCI format for a 5G physical uplink shared channel, xUSCH, grant, and

the UL/DL configuration between frames is independent and based on the UL scheduling information such that one of the following results:

a predetermined UL subframe in a previous frame is changed to a DL subframe in a current frame, an

A predetermined DL subframe in the previous frame is changed to an UL subframe in the current frame.

25. The apparatus of claim 22 or 23, wherein the UE further comprises:

means for generating hybrid automatic repeat request, HARQ, acknowledgement, HARQ-ACK in at least one UL subframe at a time indicated by the DL control information for a plurality of DL subframes depending on a UL/DL configuration,

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the UE further comprises means for generating one of:

HARQ-ACK feedback for at least one of a DL subframe in a first DL transmission period of the DL transmission periods and a DL subframe in a DL transmission period of a previous transmission frame for transmission on a last UL subframe in the transmission frame,

HARQ-ACK feedback for a particular DL subframe in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on an earliest UL subframe in the transmission frame, the earliest UL subframe being at least K subframes from the particular DL subframe, where K is fixed by a specification, and

HARQ-ACK feedback for a DL subframe in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on one or more UL subframes in the transmission frame, each UL subframe being at least K subframes after the DL subframe associated with the HARQ-ACK feedback, wherein K is fixed by a specification and the HARQ-ACK feedback is distributed as evenly as possible over the one or more UL subframes.

26. The apparatus of claim 22, wherein the particular UL/DL configuration indicates:

a configurable period independent of a previous configurable period, an

Location of UL subframe and DL subframe within frame.

27. A non-transitory computer-readable storage medium storing instructions executable by one or more processors of a User Equipment (UE), the one or more processors to configure the UE to:

decoding downlink DL control information from a base station, the DL control information indicating a particular UL/DL configuration selected from a set of predetermined uplink UL/DL configurations; and

communicate with the base station based on the particular UL/DL configuration for a configurable period of time,

wherein the configurable period for the UL/DL configuration is indicated by the DL control information and the configurable period is different from a previous configurable period.

28. The medium of claim 27, wherein:

the DL control information is received during predefined DL subframes reserved for signaling UL/DL configuration,

the predefined DL subframe is associated with a plurality of consecutive frames and is arranged in one of the plurality of consecutive frames such that the plurality of consecutive frames share the UL/DL configuration indicated by the predefined DL subframe, and

a period for applying the UL/DL configuration indicated by the predefined DL subframe is signaled by using a dedicated Information Element (IE) of a DCI format.

29. The medium of claim 27 or 27, wherein:

the UL scheduling information is carried in a DL Downlink control information DCI format for a 5G physical uplink shared channel, xUSCH, grant, and

the UL/DL configuration between frames is independent and based on the UL scheduling information such that one of the following results:

a predetermined UL subframe in a previous frame is changed to a DL subframe in a current frame, an

A predetermined DL subframe in the previous frame is changed to an UL subframe in the current frame.

30. The media of claim 27 or 28, wherein the one or more processors further configure the UE to:

generating hybrid automatic repeat request, HARQ, acknowledgement, HARQ-ACK in at least one UL subframe at a time indicated by the DL control information for a plurality of DL subframes depending on UL/DL configuration,

the UL/DL configuration comprises a transmission frame comprising a plurality of DL transmission periods and at least one UL transmission period, each DL transmission period and UL transmission period comprising a plurality of DL subframes and a plurality of UL subframes, respectively, and

the one or more processors configure the UE to generate one of:

HARQ-ACK feedback for at least one of a DL subframe in a first DL transmission period of the DL transmission periods and a DL subframe in a DL transmission period of a previous transmission frame for transmission on a last UL subframe in the transmission frame,

HARQ-ACK feedback for a particular DL subframe in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on an earliest UL subframe in the transmission frame, the earliest UL subframe being at least K subframes from the particular DL subframe, where K is fixed by a specification, and

HARQ-ACK feedback for a DL subframe in at least one of a DL transmission period in the transmission frame and a DL transmission period in a previous transmission frame for transmission on one or more UL subframes in the transmission frame, each UL subframe being at least K subframes after the DL subframe associated with the HARQ-ACK feedback, wherein K is fixed by a specification and the HARQ-ACK feedback is distributed as evenly as possible over the one or more UL subframes.

31. The medium of claim 27 or 28, wherein the particular UL/DL configuration indicates:

a configurable period independent of a previous configurable period, an

Location of UL subframe and DL subframe within frame.

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