CN108476121B - Apparatus for physical downlink shared channel transmission with short transmission time interval - Google Patents

Abstract

Briefly, in accordance with one or more embodiments, an apparatus of a user equipment includes baseband circuitry comprising one or more processors to decode a Radio Resource Control (RRC) message from an evolved node b (eNB) to obtain information comprising a short Transmission Time Interval (TTI) configuration for a UE, demodulate a cell-specific reference signal (CRS) on two of four CRS antenna ports used by the eNB for CRS transmission, estimate a channel using the two CRS antenna ports, and encode physical uplink control channel data or physical uplink shared channel data to include channel state information based on the channel estimate. The apparatus also includes radio frequency circuitry to receive data from the eNB on a low-latency physical downlink channel via the two antenna ports.

Description

Apparatus for physical downlink shared channel transmission with short transmission time interval

Cross Reference to Related Applications

This application claims the benefit of U.S. application No.62/290,865 (attorney docket No. P95931Z), filed on 3/2/2016. Said application No.62/290,865 is hereby incorporated by reference in its entirety.

Background

Low latency is an area of concern in the development of Long Term Evolution (LTE) standards promulgated by the third generation partnership project (3 GPP). Due to the nature of the internet protocol, lower latency on the wireless interface relates to achieving higher data rates and carrier aggregation enhancements. As the data rates of the LTE standard have increased in several releases in the past, the achievable delays should evolve in a similar manner. In addition, lower latency will also be able to support applications such as traffic safety and/or control, and control of critical infrastructure and industrial processes. Therefore, the 3GPP standard will evolve to provide reduced latency.

Drawings

The claimed subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, such subject matter may be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein:

fig. 1 is a diagram of a cell-specific reference signal (CRS) pattern (pattern) for four antenna ports in accordance with one or more embodiments;

fig. 2 is a diagram of a Physical Downlink Shared Channel (PDSCH) resource block mapping pattern for four antenna ports in accordance with one or more embodiments;

fig. 3 is a diagram of Physical Downlink Shared Channel (PDSCH) transmissions on adjacent subframes in accordance with one or more embodiments;

fig. 4 is a diagram of minimum Orthogonal Frequency Division Multiplexing (OFDM) for PDSCH transmissions with short TTIs in accordance with one or more embodiments;

fig. 5 is a flow diagram of physical downlink shared channel transmission with short transmission time intervals in accordance with one or more embodiments; and

fig. 6 is an illustration of example components of a wireless device in accordance with one or more embodiments.

It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

Detailed Description

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components and/or circuits have not been described in detail.

The terms "coupled" and/or "connected," along with their derivatives, may be used in the following description and/or claims. In particular embodiments, connected may be used to indicate that two or more elements are in direct physical and/or electrical contact with each other. Coupled may mean that two or more elements are in direct physical and/or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but may still cooperate and/or interact with each other. For example, "coupled" may mean that two or more elements are not in contact with each other but are indirectly connected together via another element or intermediate elements. Finally, the terms "on …", "above …" and "above …" may be used in the following description and claims. "on …," "over …," and "over …" may be used to indicate that two or more elements are in direct physical contact with each other. However, "over …" may also mean that two or more elements are not in direct contact with each other. For example, "over …" may mean that one element is higher than another element but not touching each other, and there may be another element or elements between the two elements. Furthermore, the term "and/or" may mean "and", it may mean "or", it may mean "exclusive-or", it may mean "one", it may mean "some, but not all", it may mean "none", and/or it may mean "both", although the scope of claimed subject matter is not limited in this respect. In the following description and/or claims, the terms "include" and "comprise," along with their derivatives, may be used, and are intended as synonyms for each other.

Referring now to fig. 1, an illustration of a cell-specific reference signal (CRS) pattern for four antenna ports in accordance with one or more embodiments will be discussed. Fig. 1 shows a resource block pattern 100 of Orthogonal Frequency Division Multiple Access (OFDMA) for transmissions between an evolved node b (enb) and a User Equipment (UE) according to the third generation partnership project (3GPP) standard. The horizontal axis represents time and the vertical axis represents frequency. Each resource block represents an Orthogonal Frequency Division Multiplexing (OFDM) symbol or resource block. The first slot (e.g., slot 0) includes seven OFDM symbols totaling 0.5 milliseconds (ms) in time and 12 subcarriers totaling 180 kilohertz (kHz) in frequency. One standard Transmission Time Interval (TTI) consists of two slots with a total subframe length of 1.0ms, e.g., slot 0 and slot 1.

According to the Long Term Evolution (LTE) standard of 3GPP, different transmission schemes are supported. The most commonly deployed transmission schemes in practical deployments utilize cell-specific reference signals (CRS). The eNB may transmit CRS signals to the UE on up to four antenna ports, denoted CRS port 0, CRS port 1, CRS port 2, and CRS port 3. In the example shown in fig. 1, control signals are transmitted in resource block 112, CRS signals for CRS port 0 and CRS port 1 are transmitted in resource block 114, and CRS signals for CRS port 2 and CRS port 3 are transmitted in resource block 116. Physical Downlink Shared Channel (PDSCH) data is transmitted in resource blocks 118. The PDSCH is a downlink channel that may be used for dedicated data or common data, and/or for control signaling. With PDSCH, resources may be shared among multiple UEs, data may be sent simultaneously, and may be particularly suitable for bursty Internet Protocol (IP) traffic, for example, where traffic may be intermittent or sporadic. The CRS signal is transmitted by the eNB regardless of the presence of PDSCH traffic.

As shown in fig. 1, the density of CRS patterns for CRS port 0 and CRS port 1 is higher than the density of CRS patterns for CRS port 2 and CRS port 3. In accordance with one or more embodiments, the eNB may employ a short TTI, which is shorter than the standard 1.0ms TTI shown in fig. 1, which includes 14 resource blocks 100. For PDSCH transmissions with short TTIs, having a sufficient density of CRS ports in the time domain helps to estimate the channel early and accurately. Thus, in accordance with one or more embodiments, additional processing by UEs associated with more antenna ports may be avoided in order to reduce TTIs. Thus, to enable low-delay PDSCH, where the eNB employs four CRS ports on the Physical Broadcast Channel (PBCH), if the UE is configured for short TTI, the transmission scheme may be adapted to use only the first two CRS antenna ports, port 0 and port 1. In one or more embodiments, the length of a TTI, e.g., a short TTI or a normal length TTI, may be configured for a UE using Radio Resource Control (RRC) signaling or using a combination of RRC and physical layer (PHY) signaling, where the configuration may be separate for Downlink (DL) and Uplink (UL), although the scope of the claimed subject matter is not limited in these respects. Further, short TTI transmissions may be employed across two adjacent 1.0ms downlink subframes. Also, a predetermined minimum PDSCH starting position, e.g., the fourth OFDM symbol, for a short TTI in a 1.0ms subframe. A resource block mapping pattern using only the first two antenna ports for a short TTI is shown and described below with reference to fig. 2.

Referring now to fig. 2, an illustration of a Physical Downlink Shared Channel (PDSCH) resource block mapping pattern for four antenna ports in accordance with one or more embodiments will be discussed. As shown in fig. 2, in case the eNB uses four CRS ports for a Physical Broadcast Channel (PBCH), the CRS transmission scheme for PDSCH may be adapted to resource block mapping pattern 200 to use only the first two CRS antenna ports, CRS port 0 and CRS port 1, in case the short TTI is configured for the UE. Fig. 2 shows the physical resource blocks for this arrangement from the UE perspective. As shown in fig. 2, the control signal is transmitted in resource block 112, and the CRS signals for CRS port 0 and CRS port 1 are transmitted in resource block 114. Physical Downlink Shared Channel (PDSCH) data is transmitted in resource blocks 118. Thus, although the eNB uses four CRS ports on the PBCH, PDSCH transmission for this UE is based only on the first two CRS ports, CRS port 0 and CRS port 1, such that for PDSCH demodulation, the UE estimates the channel only from CRS signals received on CRS port 0 and CRS port 1, rather than from CRS signals on all four CRS ports. On the resource blocks corresponding to CRS port 2 and CRS port 3, the UE assumes a zero power resource block 210, i.e., the UE assumes no PDSCH transmissions for CRS port 3 and CRS port 4. In addition to or instead of employing fewer CRS ports, short TTI transmissions may be employed across two adjacent 1.0ms downlink subframes, as shown and described below with respect to fig. 3.

Referring now to fig. 3, an illustration of Physical Downlink Shared Channel (PDSCH) transmissions on adjacent subframes in accordance with one or more embodiments will be discussed. In accordance with one or more embodiments, PDSCH transmissions with the short TTI configuration pattern 200 may be used on adjacent 1.0ms subframes, e.g., subframe 1 and subframe 2. As shown in fig. 3, the control signal is transmitted in resource block 112, and the CRS signals for CRS port 0 and CRS port 1 are transmitted in resource block 114. Physical Downlink Shared Channel (PDSCH) data is transmitted in resource blocks 118. Further, the first OFDM resource block of the short TTI mode 200 may be transmitted in the first 1.0ms subframe (subframe 1), and the second OFDM symbol of the short TTI mode 200 may be transmitted on the next earliest possible second OFDM symbol of the second 1.0ms subframe (subframe 2). In addition to the benefits realized by the short TTI mode 200 itself, such a transmission arrangement for the short TTI mode 200 may further improve spectral efficiency and/or reduce transmission delay. Furthermore, the additional benefit of using a predetermined minimum PDSCH starting position for the short TTI pattern 200 in a 1.0ms subframe is shown and described below with reference to fig. 4.

Referring now to fig. 4, an illustration of minimum Orthogonal Frequency Division Multiplexing (OFDM) for PDSCH transmissions with short TTIs in accordance with one or more embodiments will be discussed. In the embodiment shown in fig. 4, the PDSCH starting point of the short TTI pattern 200 in a 1.0ms subframe may be selected as a predefined symbol number, e.g., the fourth OFDM symbol, regardless of any Control Format Indicator (CFI) indication of the Physical Control Format Indicator Channel (PCFICH). The PDSCH starting point value may be configured via higher layer signaling (higher layer signaling) or fixed in the specification. The PDSCH starting point value may be configured independently for Multicast Broadcast Single Frequency Network (MBSFN) or non-MBSFN subframes, or the other derived from one. For example, the lowest OFDM symbol index in a 1.0ms subframe may be determined as min (L, 2), where L is a higher layer configuration value for non-MBSFN subframes. Fig. 4 illustrates an example embodiment in which the smallest OFDM symbol for PDSCH with short TTI is not determined by the CFI of the PCFICH. The illustrated embodiments may be beneficial for reducing UE processing time associated with PCFICH demodulation, although the scope of the claimed subject matter is not limited in this respect.

Referring now to fig. 5, a flow diagram of physical downlink shared channel transmission with short transmission time intervals in accordance with one or more embodiments will be discussed. Method 500 may include more or fewer operations than shown in fig. 5, and/or the operations may be arranged in one or more other orders than that shown, and the scope of the claimed subject matter is not limited in these respects. Further, the method 500 may be implemented as logic circuitry and/or may be implemented as machine-readable instructions, optionally stored on a non-transitory computer-readable medium having stored thereon instructions that, if executed by a machine, such as an application processor, cause the method 500 to be implemented in whole or in part. At operation 514, the eNB 510 sends the short TTI configuration to the UE 512. In one or more embodiments, the length of the TTI may be configured for the UE 512 using Radio Resource Control (RRC) signaling or using a combination of RRC and physical layer (PHY) signaling, where the configuration may be separate for Downlink (DL) and Uplink (UL), although the scope of the claimed subject matter is not limited in these respects. In some embodiments, either the eNB 510 or the UE 512 may configure the TTI length in a flexible manner. In one embodiment, a UE-specific RRC message or a System Information Block (SIB) message may be used to select a particular DL TTI and/or paired UL TTI length configuration from one or more TTI length configurations. In such an arrangement, the UE 512 may send its TTI capability information to the eNB 510 at the time of the RRC connection establishment phase. In another embodiment, a Medium Access Control (MAC) Control Element (CE) may be used to signal the TTI length. Alternatively, a combination of RRC signaling and Downlink Control Information (DCI) formats may be employed. The UE 512 may first configure several TTI length candidates through RRC signaling. UE 512 may then determine the TTI length in each subframe by decoding a Physical Downlink Control Channel (PDCCH) with a Cyclic Redundancy Check (CRC) scrambled by a private Radio Network Temporary Identifier (RNTI) value. It should be noted that these are merely example methods of how a TTI length including a short TTI may be configured, and the scope of the claimed subject matter is not limited in these respects.

At operation 516, eNB 510 transmits CRS signals to UE 512 using four CRS antenna ports (CRS antenna port 0, CRS antenna port 1, CRS antenna port 2, and CRS antenna port 3). At operation 518, UE 512 estimates the channel using only CRS antenna port 0 and CRS antenna port 1. At operation 520, the UE 512 transmits Channel Quality Indicator (CQI) and/or Channel State Information (CSI) indicating the selected channel and/or channel equalization to the eNB 510. At operation 522, the eNB 510 modulates the data to be transmitted on the PDSCH resource blocks, and at operation 524, the eNB transmits PDSCH transmissions on the selected channel. At operation 526, UE 512 demodulates PDSCH to obtain data, wherein the demodulation of the data is performed using CRS antenna port 0 and CRS antenna port 1, although the scope of the claimed subject matter is not limited in this respect.

Referring now to fig. 6, example components of a wireless device, such as an evolved nodeb (enb) device or User Equipment (UE) device, in accordance with one or more embodiments will be discussed. In some embodiments, device 600 may include application circuitry 602, one or more computer-readable storage media 612, baseband circuitry 604, Radio Frequency (RF) circuitry 606, front-end module (FEM) circuitry 608, and one or more antennas 610 coupled together at least as shown. In other embodiments, the above-described circuitry may be included, in whole or in part, in various devices, e.g., an eNB according to a cloud RAN (C-RAN) implementation, and the scope of the claimed subject matter is not limited in these respects. One OR more computer-readable media 612 may include one OR more of various types of memory OR storage devices, including volatile memory AND/OR non-volatile memory, such as flash memory, Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), NOT OR (NOR) memory, AND/OR NOT AND (NAND) memory, AND the scope of claimed subject matter is NOT limited in this respect.

The term "circuit" as used herein may refer to, may be part of, or may include the following: an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with, one or more software or firmware modules. In some embodiments, the circuitry may comprise logic that may be operated, at least in part, in hardware. The embodiments described herein may be implemented in a system using any suitably configured hardware and/or software.

The application circuit 600 may include one or more application processors. For example, the application circuit 600 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The one or more processors 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 by the memory/storage to enable various applications and/or operating systems to run on the system.

Baseband circuitry 604 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. Baseband circuitry 604 may include one or more baseband processors and/or control logic to process baseband signals received from the receive signal path of RF circuitry 606 and to generate baseband signals for the transmit signal path of RF circuitry 606. Baseband processing circuitry 604 may interface with application circuitry 602 to generate and process baseband signals and control operation of RF circuitry 606. For example, in some embodiments, baseband circuitry 604 may include a second generation (2G) baseband processor 604a, a third (3G) baseband processor 604b, a fourth generation (4G) baseband processor 604c, and/or one or more other baseband processors 604d for other existing generations, generations in development, or generations to be developed in the future (e.g., fifth generation (5G), sixth generation (6G), etc.). Baseband circuitry 604 (e.g., one or more of baseband processors 604 a-604 d) may process various radio control functions that enable communication with one or more radio networks via RF circuitry 606. 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 604 may include Fast Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functions. In some embodiments, the encoding/decoding circuitry of baseband circuitry 604 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, baseband circuitry 604 may comprise elements of a protocol stack, e.g., elements of an Evolved Universal Terrestrial Radio Access Network (EUTRAN) protocol, including, for example: physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and/or Radio Resource Control (RRC) elements. The processor 604e of the baseband circuitry 604 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) 604 f. The one or more audio DSPs 604f may include elements for compression/decompression and/or echo cancellation, and may include other suitable processing elements in other embodiments. In some embodiments, components of the baseband circuitry may be combined as appropriate in a single chip, a single chipset, or disposed on the same circuit board. In some embodiments, some or all of the constituent components of the baseband circuitry 604 and the application circuitry 602 may be implemented together, for example, on a system on a chip (SOC). In some embodiments, computer-readable storage medium or media 612 may be disposed, in whole or at least in part, on a chip separate from application circuitry 602, and in other embodiments may be fully or at least partially integrated on application circuitry 602, although the scope of claimed subject matter is not limited in these respects.

In some embodiments, the baseband circuitry 604 may provide communications compatible with one or more radio technologies. For example, in some embodiments, baseband circuitry 604 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). In some embodiments, the baseband circuitry 604 is configured to support radio communications of multiple wireless protocols, which may be referred to as multi-mode baseband circuitry.

RF circuitry 606 may support communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, RF circuitry 606 may include switches, filters, amplifiers, and the like to facilitate communication with the wireless network. RF circuitry 606 may include a receive signal path that may include circuitry to down-convert RF signals received from FEM circuitry 608 and provide baseband signals to baseband circuitry 604. RF circuitry 606 may also include a transmit signal path, which may include circuitry to up-convert baseband signals provided by baseband circuitry 604 and provide RF output signals to FEM circuitry 608 for transmission.

In some embodiments, RF circuitry 606 may include a receive signal path and a transmit signal path. The receive signal path of RF circuitry 606 may include mixer circuitry 606a, amplifier circuitry 606b, and filter circuitry 606 c. The transmit signal path of RF circuitry 606 may include filter circuitry 606c and mixer circuitry 606 a. The RF circuitry 606 may also include synthesizer circuitry 606d for synthesizing frequencies for use by the mixer circuitry 606a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 606a of the receive signal path may be configured to down-convert the RF signal received from the FEM circuitry 608 based on the synthesized frequency provided by the synthesizer circuitry 606 d. The amplifier circuit 606b may be configured to amplify the downconverted signal, and the filter circuit 606c 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 604 for further processing. In some embodiments, the output baseband signal may be a zero frequency baseband signal, but this is optional. In some embodiments, mixer circuit 606a 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 606a of the transmit signal path may be configured to up-convert the input baseband signal based on the synthesis frequency provided by the synthesizer circuitry 606d to generate the RF output signal for the FEM circuitry 608. The baseband signal may be provided by baseband circuitry 604 and may be filtered by filter circuitry 606 c. Filter circuit 606c may include a Low Pass Filter (LPF), although the scope of the embodiments is not limited in this respect.

In some embodiments, mixer circuitry 606a of the receive signal path and mixer circuitry 606a of the transmit signal path may comprise two or more mixers and may be arranged for quadrature down-conversion and/or up-conversion, respectively. In some embodiments, the mixer circuit 606a of the receive signal path and the mixer circuit 606a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuit 606a and the mixer circuit 606a of the receive signal path may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, mixer circuit 606a of the receive signal path and mixer circuit 606a 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 606 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry, and baseband circuitry 604 may include a digital baseband interface to communicate with RF circuitry 606. In some dual-mode embodiments, separate radio Integrated Circuit (IC) circuits may be provided to process signals of one or more frequency spectrums, although the scope of the embodiments is not limited in this respect.

In some embodiments, synthesizer circuit 606d 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 suitable. For example, synthesizer circuit 606d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase locked loop with a frequency divider.

The synthesizer circuit 606d may be configured to synthesize an output frequency for use by the mixer circuit 606a of the RF circuit 606 based on the frequency input and the divider control input. In some embodiments, synthesizer circuit 606d may be a fractional-N/N +1 synthesizer.

In some illustrative embodiments, the frequency input may be provided by a Voltage Controlled Oscillator (VCO), but this is optional. The divider control input may be provided by the baseband circuitry 604 or the application processor 602 depending on the 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 602.

Synthesizer circuit 606d of RF circuit 606 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 at most 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 606d 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, etc.) and used with a quadrature generator and divider circuit to generate a plurality of signals having a plurality of mutually different phases at the carrier frequency. In some embodiments, the output frequency may be a Local Oscillator (LO) frequency (fLO). In some embodiments, RF circuit 606 may include an in-phase-quadrature (IQ)/polarity converter.

FEM circuitry 608 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 710, amplify the received signals, and provide amplified versions of the received signals to RF circuitry 606 for further processing. FEM circuitry 608 may also include a transmit signal path, which may include circuitry configured to amplify signals provided for transmission by RF circuitry 606 for transmission by one or more of one or more antennas 610.

In some embodiments, FEM circuitry 608 may include a transmit/receive (TX/RX) switch to switch between transmit mode and receive mode operation. FEM circuitry 608 may include a receive signal path and a transmit signal path. The receive signal path of FEM circuitry 608 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 RF circuitry 606). The transmit signal path of FEM circuitry 608 may include a Power Amplifier (PA) to amplify an input RF signal (e.g., provided by RF circuitry 606) and one or more filters to generate an RF signal for subsequent transmission (e.g., by one or more of one or more antennas 610). In some embodiments, device 600 may include additional elements, such as, for example, memory and/or storage, a display, a camera, a sensor, and/or an input/output (I/O) interface, although the scope of claimed subject matter is not limited in this respect.

The following are example implementations of the subject matter described herein. It should be noted that any of the examples and variations thereof described herein can be used in any permutation or combination of any other one or more examples or variations, but the scope of the claimed subject matter is not limited in these respects.

In an example one, an apparatus of a User Equipment (UE) includes baseband circuitry comprising one or more processors to: decoding a Radio Resource Control (RRC) message from an evolved node b (eNB) to obtain information including a Transmission Time Interval (TTI) configuration for the UE to use a short TTI, demodulating CRS on two of four CRS antenna ports (port 0 and port 1) used by the eNB for cell-specific reference signal (CRS) transmission (port 0, port 1, port 2, and port 3), estimating a channel using two of the four CRS antenna ports, and encoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data based on the channel estimation to include Channel State Information (CSI). In example two, the apparatus may include the subject matter of example one or any of the examples described herein, and may further include Radio Frequency (RF) circuitry to receive data from the eNB on a low latency physical downlink channel via the two antenna ports. In example three, the apparatus may include the subject matter of example one or any of the examples described herein, wherein the low latency physical downlink channel is a low latency physical downlink shared channel (L-PDSCH). In example four, the apparatus may be one or include the subject matter of any of the examples described herein, wherein the low latency physical downlink channel is a low latency physical downlink control channel (L-PDCCH). In example five, the apparatus may include the subject matter of example one or any of the examples described herein, wherein the one or more processors of the baseband circuitry are configured to assume zero power on resource elements corresponding to CRS antenna port 2 and CRS antenna port 3 to receive data on the low-latency physical channel. In example six, the apparatus may be one or include the subject matter of any of the examples described herein, wherein the data is received from the eNB via CRS antenna port 0 and CRS antenna port 1. In example seven, the apparatus may include the subject matter of example one or any of the examples described herein, wherein the CSI is estimated for CRS antenna port 0 and CRS antenna port 1. In example eight, the apparatus may include the subject matter of example one or any of the examples described herein, wherein the data is received from the eNB on Orthogonal Frequency Division Multiplexing (OFDM) symbols of two adjacent downlink subframes. In example nine, the apparatus may include the subject matter of example one or any of the examples described herein, wherein the data is received from the eNB on a predetermined starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe. In example ten, the apparatus may include the subject matter of example one or any of the examples described herein, wherein a lowest starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe is configured by higher layer signaling for the UE. In example 11, the apparatus may include the subject matter of example one or any of the examples described herein, wherein a lowest starting OFDM symbol of the subframe is different for a Multicast Broadcast Single Frequency Network (MBSFN) subframe and a non-MBSFN subframe. In example twelve, the apparatus may include the subject matter of example one or any of the examples described herein, wherein a lowest starting OFDM symbol for a subframe for MBSFN is derived from a lowest starting OFDM symbol L of a non-MBSFN subframe as a minimum value between L and 2. In example thirteen, the apparatus may include the subject matter of example one or any of the examples described herein, wherein the predetermined starting OFDM symbol of the subframe is OFDM symbol 3 or OFDM symbol 4.

In example fourteen, an apparatus of an evolved node b (enb) comprises baseband circuitry comprising one or more processors to: encoding a Radio Resource Control (RRC) message to include information for a Transmission Time Interval (TTI) configuration for a User Equipment (UE) using a short TTI, modulating CRSs on four CRS antenna ports (port 0, port 1, port 2, and port 3) for cell-specific reference signal (CRS) transmission, and decoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data to include Channel State Information (CSI) from the UE, wherein the CSI is estimated by the UE for CRS antenna port 0 and CRS antenna port 1. In example fifteen, the apparatus may include the subject matter of example fourteen or any example described herein, and may further include Radio Frequency (RF) circuitry to transmit data to the UE on the low-latency physical downlink channel via CRS antenna port 0 and CRS antenna port 1. In example sixteen, the apparatus may include the subject matter of example fourteen or any example described herein, wherein the low-latency physical downlink channel is a low-latency physical downlink shared channel (L-PDSCH). In example seventeen, the apparatus may include the subject matter of example fourteen or any example described herein, wherein the low latency physical downlink channel is a low latency physical downlink control channel (L-PDCCH). In example eighteen, the apparatus may include the subject matter of example fourteen or any example described herein, wherein the data is transmitted to the UE on Orthogonal Frequency Division Multiplexing (OFDM) symbols of two adjacent downlink subframes. In example nineteen, the apparatus may include the subject matter of example fourteen or any example described herein, wherein the data is transmitted to the UE on a predetermined starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe. In example twenty, the apparatus may include the subject matter of example fourteen or any example described herein, wherein a lowest starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe is configured by higher layer signaling for the UE. In example twenty-one, the apparatus may include the subject matter of example fourteen or any example described herein, wherein a lowest starting OFDM symbol of a subframe is different for a Multicast Broadcast Single Frequency Network (MBSFN) subframe and a non-MBSFN subframe. In example twenty-two, the apparatus may include the subject matter of example fourteen or any example described herein, wherein a lowest starting OFDM symbol for a subframe for MBSFN is derived from a lowest starting OFDM symbol L of a non-MBSFN subframe as a minimum value between L and 2. In example twenty-three, the apparatus may include the subject matter of example fourteen or any example described herein, wherein the predetermined starting OFDM symbol of the subframe is OFDM symbol 3 or OFDM symbol 4.

In example twenty-four, one or more computer-readable media may have instructions stored thereon that, when executed by a User Equipment (UE), cause: decoding a Radio Resource Control (RRC) message from an evolved node b (eNB) to obtain information including a Transmission Time Interval (TTI) configuration for the UE using a short TTI, demodulating CRS on two of four CRS antenna ports (port 0 and port 1) used by the eNB for cell-specific reference signal (CRS) transmission (port 0, port 1, port 2, and port 3), estimating a channel using two of the four CRS antenna ports, encoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data based on the channel estimation to include Channel State Information (CSI), and decoding data from the eNB on a low-latency physical downlink channel via the two antenna ports. In example twenty-five, the one or more computer-readable media may include the subject matter of example one or any of the examples described herein, wherein the low latency physical downlink channel is a low latency physical downlink shared channel (L-PDSCH) or a low latency physical downlink control channel (L-PDCCH). In example twenty-six, the one or more computer-readable media may include the subject matter of example one or any of the examples described herein, wherein the data is received from the eNB on Orthogonal Frequency Division Multiplexing (OFDM) symbols of two adjacent downlink subframes.

In example twenty-seventh, one or more computer-readable media may have instructions stored thereon that, when executed by an evolved node b (enb), cause: encoding a Radio Resource Control (RRC) message to include information for a User Equipment (UE) to use a Transmission Time Interval (TTI) configuration of a short TTI, modulating CRS on four CRS antenna ports (port 0, port 1, port 2, and port 3) for cell-specific reference signal (CRS) transmission, decoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data to include Channel State Information (CSI) from the UE, wherein the CSI is estimated by the UE for CRS antenna port 0 and CRS antenna port 1, and encoding data transmitted to the UE on a low-latency physical downlink channel via CRS antenna port 0 and CRS antenna port 1. In example twenty-eight, the one or more computer-readable media may include the subject matter of example one or any of the examples described herein, wherein the low latency physical downlink channel is a low latency physical downlink shared channel (L-PDSCH) or a low latency physical downlink control channel (L-PDCCH). In example twenty-nine, the one or more computer-readable media may include the subject matter of example one or any of the examples described herein, wherein the data is transmitted to the UE on a predetermined starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe. In example 30, the one or more computer-readable media may include the subject matter of example one or any of the examples described herein, wherein a lowest starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of the subframe is configured by higher layer signaling for the UE.

Although the claimed subject matter has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and/or scope of the claimed subject matter. It is believed that the subject matter pertaining to physical downlink shared channel transmissions with short transmission time intervals and many of its attendant utilities will be understood by the forgoing description, and it will be apparent that various changes may be made in the form, construction and/or arrangement of the components thereof without departing from the scope and/or spirit of the claimed subject matter or without sacrificing all of its material advantages, the form herein before described being merely an explanatory embodiment thereof, and/or further without providing substantial change thereto. It is the intention of the claims to encompass and/or include such changes.

Claims (25)

1. An apparatus of a User Equipment (UE), comprising baseband circuitry comprising one or more processors to:

decoding a Radio Resource Control (RRC) message from a base station to obtain information, the information comprising a Transmission Time Interval (TTI) configuration for use of a short TTI by the UE;

demodulating CRSs on two of four CRS antenna ports (port 0, port 1, port 2, and port 3) used by the base station for cell-specific reference signal (CRS) transmission;

estimating a channel using the two of the four CRS antenna ports; and

encoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data to include Channel State Information (CSI) based on the channel estimate.

2. The apparatus of claim 1, further comprising:

radio Frequency (RF) circuitry to receive data from the base station on a low-latency physical downlink channel via the two CRS antenna ports.

3. The apparatus of claim 2, wherein the low-latency physical downlink channel is a low-latency physical downlink shared channel (L-PDSCH).

4. The apparatus of any of claims 2-3, wherein the low-latency physical downlink channel is a low-latency physical downlink control channel (L-PDCCH).

5. The apparatus of any of claims 2-3, wherein the one or more processors of the baseband circuitry are configured to: assume zero power on resource elements corresponding to CRS antenna port 2 and CRS antenna port 3 to receive data on the low latency physical downlink channel.

6. The apparatus of any of claims 2-3, wherein the data is received from the base station via CRS antenna port 0 and CRS antenna port 1.

7. The apparatus of claim 1, wherein the CSI is estimated for CRS antenna port 0 and CRS antenna port 1.

8. The apparatus of any of claims 2-3 and 7, wherein the data is received from the base station on Orthogonal Frequency Division Multiplexing (OFDM) symbols of two adjacent downlink subframes.

9. The apparatus of any of claims 2-3 and 7, wherein the data is received from the base station on a predetermined starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of a subframe.

10. The apparatus of any of claims 2-3 and 7, wherein a lowest starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of a subframe is configured for the UE by higher layer signaling.

11. An apparatus of a base station, comprising baseband circuitry comprising one or more processors to:

encoding a Radio Resource Control (RRC) message to include information configured for a Transmission Time Interval (TTI) configured for a User Equipment (UE) to use a short TTI;

modulating CRSs on four CRS antenna ports (port 0, port 1, port 2 and port 3) for cell-specific reference signal (CRS) transmission; and is

Decoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data that includes Channel State Information (CSI) from the UE, wherein the CSI is estimated by the UE for CRS antenna port 0 and CRS antenna port 1.

12. The apparatus of claim 11, further comprising:

radio Frequency (RF) circuitry to transmit data to the UE on a low-latency physical downlink channel via CRS antenna port 0 and CRS antenna port 1.

13. The apparatus of claim 12, wherein the low-latency physical downlink channel is a low-latency physical downlink shared channel (L-PDSCH).

14. The apparatus of any one of claims 12-13, wherein the low-latency physical downlink channel is a low-latency physical downlink control channel (L-PDCCH).

15. The apparatus of any of claims 12-13, wherein the data is transmitted to the UE on Orthogonal Frequency Division Multiplexing (OFDM) symbols of two adjacent downlink subframes.

16. The apparatus of any of claims 12-13, wherein the data is transmitted to the UE on a predetermined starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of a subframe.

17. The apparatus of any of claims 12-13, wherein a lowest starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of a subframe is configured by higher layer signaling for the UE.

18. The apparatus of claim 17, wherein a lowest starting OFDM symbol of the subframe is different for a Multicast Broadcast Single Frequency Network (MBSFN) subframe and a non-MBSFN subframe.

19. An apparatus, comprising:

apparatus for: decoding a Radio Resource Control (RRC) message from a base station to obtain information, the information comprising a Transmission Time Interval (TTI) configuration for a UE to use a short TTI;

apparatus for: demodulating CRSs on two of four CRS antenna ports (port 0, port 1, port 2, and port 3) used by the base station for cell-specific reference signal (CRS) transmission;

apparatus for: estimating a channel using the two of the four CRS antenna ports;

apparatus for: encoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data to include Channel State Information (CSI) based on the channel estimate; and

apparatus for: decoding data from the base station on a low-latency physical downlink channel via the two antenna ports.

20. The device of claim 19, wherein the low-latency physical downlink channel is a low-latency physical downlink shared channel (L-PDSCH) or a low-latency physical downlink control channel (L-PDCCH).

21. The apparatus of any of claims 19-20, wherein the data is received from the base station on Orthogonal Frequency Division Multiplexing (OFDM) symbols of two adjacent downlink subframes.

22. An apparatus, comprising:

apparatus for: encoding a Radio Resource Control (RRC) message to include information configured for a Transmission Time Interval (TTI) configured for a User Equipment (UE) to use a short TTI;

apparatus for: modulating CRSs on four CRS antenna ports (port 0, port 1, port 2 and port 3) for cell-specific reference signal (CRS) transmission;

apparatus for: decoding Physical Uplink Control Channel (PUCCH) data or Physical Uplink Shared Channel (PUSCH) data that includes Channel State Information (CSI) from the UE, wherein the CSI is estimated by the UE for CRS antenna port 0 and CRS antenna port 1; and

apparatus for: encoding data transmitted to the UE on a low-latency physical downlink channel via CRS antenna port 0 and CRS antenna port 1.

23. The device of claim 22, wherein the low-latency physical downlink channel is a low-latency physical downlink shared channel (L-PDSCH) or a low-latency physical downlink control channel (L-PDCCH).

24. The apparatus of any of claims 22-23, wherein the data is transmitted to the UE on a predetermined starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of a subframe.

25. The apparatus of any of claims 22-23, wherein a lowest starting Orthogonal Frequency Division Multiplexing (OFDM) symbol of a subframe is configured for the UE by higher layer signaling.

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