WO2016204714A1

WO2016204714A1 - Frame structure and hybrid automatic retransmission request procedure

Info

Publication number: WO2016204714A1
Application number: PCT/US2015/000449
Authority: WO
Inventors: Senjie Zhang; Hong Cheng; Jong-Kae Fwu
Original assignee: Intel Corporation
Priority date: 2015-06-18
Filing date: 2015-12-23
Publication date: 2016-12-22

Abstract

An architecture is configured to be employed within one or more user evolved node Bs (eNodeBs). The architecture includes frame logic and a transmit component. The frame logic is configured to generate a frame using time division duplexing (TDD) and a frame having a plurality of subframes. The subframes include a special subframe having a downlink/uplink proportional configuration. The transmit component is configured to transmit the frame as part of a transmit signal using time division duplexing (TDD).

Description

FRAME STRUCTURE AND HYBRID AUTOMATIC RETRANSMISSION REQUEST

PROCEDURE

REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. provisional application 62/181 ,653, filed June 18, 2015, the contents of which are herein incorporated by reference in their entirety.

FIELD

[0002] The present disclosure relates to mobile wireless communication and to a frame structure and a hybrid automatic retransmission request procedure.

BACKGROUND

[0003] Cellular communications are an increasingly important form of communicating and transferring information. One important characteristic of cellular communication is latency. Generally, latency is a transit time from one entity to another entity. The latency includes transmission time along a medium, processing time and the like.

Having a relatively high latency leads to delayed communications, pauses during voice communications, delayed response times and the like.

[0004] Another important characteristic of cellular communication is error correction. Errors can occur through data corruption, interference and the like. Errors can sometimes be corrected using a technique, such as a forward error correction code (FEC), where parity bits are sent along with a message or in response to a request. The correction technique may be able to correct the error(s). If not, retransmission of the data is requested, which takes extra time. Additionally, if high latency is present, the retransmission takes even more time further delaying communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Fig. 1 is a diagram illustrating an architecture using an enhanced frame structure and an enhanced retransmission procedure according to various aspects.

[0006] Fig. 2 is a diagram illustrating subframe types in accordance with various aspects.

[0007] Fig. 3A is a table illustrating example system parameters considered for a HARQ or retransmission procedure.

[0008] Fig. 3B is a table illustrating retransmission parameters based on a set of system parameters.

[0009] Fig. 4 is table showing a set of example DUUL frame configurations based on system parameters.

[0010] Fig. 5 is a flow diagram illustrating a method of performing cellular

communication including enhanced retransmission and an enhanced frame structure.

[0011] FIG. 6 illustrates, for one embodiment, example components of a User Equipment (UE) device.

DETAILED DESCRIPTION

[0012] The present disclosure will now be described with reference to the attached drawing figures, wherein like reference numerals are used to refer to like elements throughout, and wherein the illustrated structures and devices are not necessarily drawn to scale. As utilized herein, terms "component," "system," "interface," and the like are intended to refer to a computer-related entity, hardware, software (e.g., in execution), and/or firmware. For example, a component can be a processor (e.g., a

microprocessor, a controller, or other processing device), a process running on a processor, a controller, an object, an executable, a program, a storage device, a computer, a tablet PC, an electronic circuit and/or a mobile phone with a processing device. By way of illustration, an application running on a server and the server can also be a component. One or more components can reside within a process, and a component can be localized on one computer and/or distributed between two or more computers. A set of elements or a set of other components can be described herein, in which the term "set" can be interpreted as "one or more."

[0013] Further, these components can execute from various computer readable storage media having various data structures stored thereon such as with a module, for example. The components can communicate via local and/or remote processes such as in accordance with a signal having one or more data packets (e.g. , data from one component interacting with another component in a local system, distributed system, and/or across a network, such as, the Internet, a local area network, a wide area network, or similar network with other systems via the signal).

[0014] As another example, a component can be an apparatus with specific functionality provided by mechanical parts operated by electric or electronic circuitry, in which the electric or electronic circuitry can be operated by a software application or a firmware application executed by one or more processors. The one or more processors can be internal or external to the apparatus and can execute at least a part of the software or firmware application. As yet another example, a component can be an apparatus that provides specific functionality through electronic components without mechanical parts; the electronic components can include one or more processors therein to execute software and/or firmware that confer(s), at least in part, the

functionality of the electronic components.

[0015] Use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied under any of the foregoing instances. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form. Furthermore, to the extent that the terms "including", "includes", "having", "has", "with", or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term

"comprising".

[0016] As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute 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 the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware. [0017] Latency is an important characteristic for cellular communications and cellular systems. Generally, latency is a transit time from one entity to another. For 5G cellular systems, user latency is defined as a one way transit time between a service data unit (SDU) packet being available at an internet protocol (IP) layer in a user equipment (UE) or enhanced node B (eNodeB) and the availability of this packet at an IP layer in another UE or eNodeB. Typically, for 5G systems, the user plane latency is expected to be less than about 1 ms.

[0018] Some factors that impact latency include frame structure and error correction. The frame structure, also referred to as a radio frame structure, includes a plurality of subframes. Each subframe typically includes a downlink transmission or uplink transmission and a guard period (GP) to enhance communications. The uplink transmission is in a direction from a UE to eNodeB whereas the downlink transmission is in a direction from eNodeB to UE. The uplink and downlink transmissions generally include data packets, control information, supporting signals, reference signals and the like. The control information includes, for example, acknowledgement (ACK), not acknowledgement, and the like. The number of subframes within the frame structure can vary. In one example, the number of subframes N_sf is 8 or 10 and the subframes are indexed as 0, 1 , 2, N_sf - 1.

[0019] The GP is a burst period where transmission is not permitted. The GP is used to protect adjacent bursts from transmission overlap due to, for example, propagation time from the UE to the eNodeB or base station. A GP is typically placed at the end of a subframe to mitigate interference from a subsequent subframe.

[0020] However, a GP is helpful when there is a transition or change in direction of transmission. However, if a downlink frame follows another downlink from or an uplink frame follows another uplink frame, the GP is not needed. The length of the GP unnecessarily adds to the user plane latency and degrades cellular communication.

[0021] Additionally, special subframes exist that allow both downlink and uplink within the same subframe. However, these subframes have rigid fields or lengths that can require additional subframes or leave portions of the rigid fields unused.

[0022] Errors can occur through data corruption, interference and the like. Errors can sometimes be corrected using a technique, such as a forward error correction code (FEC), where parity bits are sent along with a message or in response to a request. One technique involves automatic retransmission request (ARQ), where retransmission of data is automatically requested upon detection of an error. Another technique involves hybrid automatic retransmission request (HARQ), where an attempt is made to correct an error and retransmission is requested if the error cannot be corrected.

[0023] Thus, in either technique, retransmission can be requested due to the error. This retransmission takes extra time. Additionally, if high user plane latency is present, the retransmission takes even more time further degrading communications.

[0024] The present disclosure includes various aspects/embodiments that facilitate cellular communications and enhance latency. The aspects include a frame structure and hybrid automatic retransmission request (HARQ) procedure for 5G time division duplexing (TDD) systems. The various aspects provide relatively low latency while providing low GP overhead, traffic adaptation, relatively low processing delay and the like.

[0025] Fig. 1 is a diagram illustrating an architecture 100 using an enhanced frame structure and an enhanced retransmission procedure according to various aspects or embodiments. The architecture 100 mitigates latency and enhances cellular

communication. The architecture 100 is incorporated into a network entity, such as a base station, eNodeB, mobile device, user equipment and the like.

[0026] The architecture 100 includes frame logic 102, retransmission logic 108 and a transmit component 104. The frame logic 102 and the retransmission logic can, for example, be implemented in circuitry and/or logic. The frame logic 102 is configured to generate a frame 110 using time division duplexing (TDD). The frame, also referred to as a radio frame, includes a plurality or number of subframes. In one example, a frame includes ten subframes and each subframe includes 14 OFDM/SC-FDMA symbols.

[0027] The frame logic 102 configures the types of subframes used in the frame 1 10. The configuration of subframes within a radio frame is referred to as a frame

downlink/uplink (DL/UL) configuration. The DIJUL configuration is based on

transmission needs, expected transmission needs and the like.

[0028] The subframes generally include 3 types, a downlink subframe, an uplink subframe and a special subframe. The downlink subframe includes a downlink transmission field and a GP. The downlink field is for downlink transmission or communication from a base station, such as an eNodeB, to a mobile device, such as a UE. The uplink subframe includes an uplink transmission field and a GP. The uplink field is for uplink transmission or communication from a mobile device, such as a UE, to a base station, such as an eNodeB. [0029] The special subframe includes a downlink/uplink proportional configuration. The special subframe includes a special downlink transmission field, a first GP, a special uplink transmission field, and a second GP. The lengths of the special downlink field and the special uplink field can be varied and defined by a ratio with respect to each other from 0% to 100%. Thus, for example, the special subframe can set the special downlink field to length of 0 and set the special uplink field to a maximum length. The length, in one example, is in terms of symbols.

[0030] The uplink and downlink transmissions generally include data packets, control information, supporting signals, reference signals and the like. The control information includes, for example, acknowledgement (ACK), not acknowledgement, and the like. The number of subframes within the frame structure can vary. The length of the subframes are typically fixed to a set length. The number of subframes within the frame structure can vary. In one example, the number of subframes N_sr is 8 or 10 and the subframes are indexed as 0, 1 , 2, N_sf - 1. Each subframe is used by one or more UEs.

[0031] The frame logic 102 is configured to allocate or control lengths of the various fields or portions in the subframes. The frame logic 102 allocates the length of GPs based on succeeding subframes and reduces the length of the GPs where the GPs are not needed or required. The unused lengths are reallocated to downlink and/or uplink fields.

[0032] For example, a GP of a downlink subframe is set to a length of zero upon a subsequent subframe also being a downlink subframe or a special subframe. The downlink transmission field is allocated additional lengths or symbols. A GP of an uplink subframe is set to a length of zero upon a subsequent subframe also being an uplink subframe. Similarly, the uplink transmission field length is increased to make use of the extra available portion of the subframe not used by the GP. A first guard period of a special subframe can be set to zero if the special uplink transmission field is set to zero. A second guard period of the special subframe can be set to zero if the subsequent subframe is an uplink subframe.

[0033] The frame logic 102 is also configured to set the downlink/uplink proportion configuration for the special subframe based on expected need, established

communications and the like. The downlink/uplink proportion configuration defines a ratio or percentage of length of the special downlink transmission field to the special uplink transmission field. [0034] The retransmission logic 108 is configured to determine retransmission parameters based on system parameters. Then, the retransmission logic 108 initiates a retransmission procedure and sets subframes according to the determined

retransmission parameters. The retransmission procedure, in this example, is a HARQ retransmission procedure. Generally, the retransmission logic sets the retransmission procedure according to one or more factors, such as the frame DL/UL configuration, subframe length, processing delay and the like.

[0035] The HARQ or retransmission procedure depends on system parameters including DL/UL configuration, number of subframes, subframe duration, transmitter processing delay, receiver processing delay, frame duration, number of GP, allowed or maximum GP overhead and the like.

[0036] Generally, the retransmission procedure involves detecting an error in a received subframe at a receiving network entity, such as a UE or an eNodeB. The network entity notifies that transmitting network entity and requests retransmission of the errored subframe. The transmitting network entity can be an eNodeB or the UE. The transmitting network entity retransmits a corrected subframe. The corrected subframe is received and the receiving network entity. The number of frames or delay for each portion depends on the system parameters.

[0037] For a downlink transmission from an eNodeB to a UE, upon the detection and cyclic redundancy checking (CRC) checking result of data packet at subframe n - K_d, the UE transmits ACK/NACK at subframe n; upon the detection of

ACK/NACK at subframe n, the eNodeB should re-transmit the corresponding data packet at subframe n + Q_d, or later subframes.

[0038] For uplink transmission from the UE to the eNodeB, upon the detection and CRC checking result of data packet at subframe n - K_u, the eNodeB should transmit ACK/NACK at subframe n; upon the detection of ACK/NACK and scheduling information at subframe n, the UE can re-transmit the corresponding data packet at subframe n + Q_u, or later subframes.

[0039] The retransmission parameters K_dl Q_d, K_u and Q_u vary according to the radio frame configuration, including the subframes. For downlink transmissions from an eNodeB to a UE, the parameter K_d indicates an offset for ACK provided at a current frame by the UE, frame n. The parameter Q_d indicates an offset for a retransmission by the eNodeB provided at a current frame n by the eNodeB. [0040] For uplink transmissions, the parameter K_u indicates an offset for ACK provided at a current frame n by an eNodeB. The parameter Q_u indicates an offset for a retransmission by the UE provided at the current frame n.

[0041] The transmit component 104 is configured to process the frame 1 10 from the frame logic 102 and generate a transmission signal. Additionally, the transmit component is configured to perform the retransmission procedure as determined by the retransmission component 108. One or more antenna 106 provide the transmission signal and also receive signals. The transmission signal is received and utilized by one or more network entities 112. The network entities 1 12 can include, for example, one or more UE, one or more eNodeB, and the like.

[0042] Fig. 2 is a diagram illustrating subframe types 200 in accordance with various aspects or embodiments. The subframe types are controlled and allocated by frame logic, such as the frame logic 102, to enhance communication and mitigate user plane latency. It is appreciated that variations in the shown subframe types 200 are contemplated.

[0043] A downlink subframe type 201 is a subframe for downlink transmission, which includes transmissions from an eNodeB to a UE. The downlink subframe type 201 has a fixed length and includes a downlink field and a GP. The length of the downlink field and the GP can vary dynamically as determined by the frame logic. When one is decreased, the other field is increased.

[0044] An uplink subframe type 202 is a subframe used for uplink transmission, such as transmissions from a UE to an eNodeB. The uplink subframe type 202 has a fixed length and includes an uplink field and a GP. The length of the uplink field and the GP can vary dynamically as determined by the frame logic. When one field is decreased, the other field is increased.

[0045] A special subframe type 203 is a special subframe that can be used for both downstream and upstream transmission. The special subframe type 203 includes a special downlink field, a first GP, a special uplink field, and a second GP. The length of the special downlink field, the first GP, the special uplink field and the second GP can vary dynamically as determined by the frame logic. In one example, the special downlink field and/or the special uplink field can be adjusted to a length of zero or one symbol.

[0046] Fig. 3A is a table illustrating example system parameters 300 considered for a HARQ or retransmission procedure. Retransmission parameters, described above, are determined based on the system parameters 300. Then, the HARQ procedure is followed using the determined retransmission parameters.

[0047] It is appreciated that the shown system parameters 300 are provided for illustrative purposes. Various aspects can utilize additional parameters and/or omit some of the shown parameters. Further, the values provided are for illustrative purposes and to aid understanding. It is appreciated that the system parameters 300 can have other values. The system parameters 300 are for one or more frames used in cellular communication.

[0048] The table depicts the system parameters 300 for a single radio frame. The frame has a duration, in time, of 1 ms. There are 10 subframes, thuse each subframe has a duration of 0.1 ms. There are 2 guard periods (GP). The maximum GP overhead is set to 4 percent. The transmitter has a processing delay of 0.2 ms. The transmitter processing delay corresponds to twice a transmission time interval (TTI), which is twice the subframe duration. The receiver has a processing delay of 0.3 ms. The receiver processing delay is three times the transmission time interval, which is three times the subframe duration.

[0049] Fig. 3B is a table illustrating retransmission parameters 301 based on a set of system parameters 300. The retransmission parameters 301 are provided for illustrative purposes. It is appreciated that the retransmission parameters 301 can have other suitable values in various aspects.

[0050] The retransmission parameters 301 of Fig. 3B are based on the system parameters 300 shown in Fig. 3A. The retransmission parameters 301 are shown for an example frame that complies with the system parameters 300.

[0051] A DUUL configureation index is provided in a first column. A second column provides details and labels for subframe type and the retransmission parameters. The retransmission parameters include K_d, Q_d, K_u and Q_u, which identify frame offsets as shown above. There are 10 columns provided for various subframes according to subframe index. Each subframe column indicates a type of subframe, offset for ACK K_d for downlink transmission, an offset for retransmission Q_d for a downlink transmission, an offset for ACK K_u for an uplink transmission and an offset for retransmission Q_u for an uplink transmission.

[0052] An example 302 is provided for illustrative purposes assuming that a current subframe is index 7. The subframe type is an uplink (U) transmission frame. Thus, transmission is from a UE to an eNodeB. The UE provides an ACK, as K_d, which has a value of 7. Thus, the ACK is indicating that an error occurred 7 subframes earlier, on subframe 0. The UE also provides the retransmission offset Q_d, here shown as 13. The retransmission offset informs the sender of subframe 0 that subframe 7 should be retransmitted 13 or more subframes from the current subframe.

[0053] A second example 303 is described where a current subframe is subframe index 1 . The subframe type is a downlink (D) transmission frame. Thus, transmission is from an eNodeB to a UE. The eNodeB provides multiple ACKs, as K_u, which has a values of 8, 12 and 9. Thus, the ACKs are indicating that an errors occurred 8, 12 and 9 subframes earlier. The eNodeB also provides the

retransmission offset Q_u, here shown as 1 1. The retransmission offset informs the sender, here the UE, of the error occurring subframes and that the subframes should be retransmitted 1 1 or more subframes from or after the current subframe.

[0054] The average frame alignment time for downlink and uplink, noted as T_fad and T_fau, are determined by the radio frame DL/UL configuration.

[0055] The average HARQ RTT for downlink and uplink, noted as T_md and T_rttu, are determined by the HARQ procedure (indirectly by the DL/UL configuration).

[0056] Fig. 3B shows the value of T_fad, T_fau, T_rttd and T_rttu in unit of micro seconds (ms).

[0057] The overall downlink latency can be calculated as:

[0058]

L_d = TX processing delay + Tf_ad + TTI duration + RX processnig delay + T_rttd x BIER

[0059] The overall uplink latency can be calculated as:

L_u = TX processing delay + T_fau + TTI duration + RX processnig delay + T_rttu x BIER

[0060] Assuming BLER=0, the value of L_d and L_u for all DL/U L configurations and HARQ procedures can be determined.

[0061] For the example shown in Fig. 3B, the downlink latency L_d is shown as 0.93 ms and the uplink latency L_u is shown as 0.68 ms.

[0062] Fig. 4 is table showing a set of example DUUL frame configurations based on system parameters. The configurations include the example from Fig. 3B and includes additional configurations from AO to A9. The DL/UL frame configurations are based on the system parameters of Fig. 3A. Each configuration provides retransmission parameters, if any, for each subframe as shown. [0063] Fig. 5 is a flow diagram illustrating a method 500 of performing cellular communication including enhanced retransmission and an enhanced frame structure.

[0064] A downlink/uplink frame configuration is selected from a plurality of frame configurations based on system parameters at block 502. The frame configuration includes sub frame types, including downlink, uplink and special subframes. The plurality of frame configurations can be in accordance with the system parameters. Further, the plurality of frame configurations have varied downlink/uplink ratios and the like.

[0065] Lengths for various fields and guard periods for a plurality of subframes are configured or allocated at block 504. For example, a guard period for a downlink subframe with a subsequent adjacent downlink subframe can be set to a length of zero.

[0066] Retransmission parameters are determined based on the system parameters at block 506. The retransmission parameters include downlink ACK offset, downlink retransmission offset, uplink ACK offset, and uplink retransmission offset.

[0067] A retransmission or HARQ procedure is performed at block 508 according to the retransmission parameters.

[0068] While the methods described within this disclosure are illustrated in and described herein as a series of acts or events, it will be appreciated that the illustrated ordering of such acts or events are not to be interpreted in a limiting sense. For example, some acts may occur in different orders and/or concurrently with other acts or events apart from those illustrated and/or described herein. In addition, not all illustrated acts may be required to implement one or more aspects or embodiments of the description herein. Further, one or more of the acts depicted herein may be carried out in one or more separate acts and/or phases.

[0069] As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute 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 the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware.

[0070] Embodiments described herein can be implemented into a system using any suitably configured hardware and/or software. FIG. 6 illustrates, for one embodiment, example components of a User Equipment (UE) device 600. In some embodiments, the UE device 600 (e.g., the wireless communication device 101) can include application circuitry 602, baseband circuitry 604, Radio Frequency (RF) circuitry 606, front-end module (FEM) circuitry 608 and one or more antennas 680, coupled together at least as shown.

[0071] The application circuitry 602 can include one or more application processors. For example, the application circuitry 602 can include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) can include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors can be coupled with and/or can include memory/storage and can be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system.

[0072] The baseband circuitry 604 can include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 604 can include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 606 and to generate baseband signals for a transmit signal path of the RF circuitry 606. Baseband processing circuity 604 can interface with the application circuitry 602 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 606. For example, in some embodiments, the baseband circuitry 604 can include a second generation (2G) baseband processor 604a, third generation (3G) baseband processor 604b, fourth generation (4G) baseband processor 604c, and/or other baseband processor(s) 604d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 604 (e.g., one or more of baseband processors 604a-d) can handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 606. The radio control functions can include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 604 can include Fast-Fourier Transform (FFT), precoding, and/or constellation

mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 604 can include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and can include other suitable functionality in other embodiments.

[0073] In some embodiments, the baseband circuitry 604 can include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 604e of the baseband circuitry 604 can be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry can include one or more audio digital signal processor(s) (DSP) 604f. The audio DSP(s) 604f can be include elements for compression/decompression and echo cancellation and can include other suitable processing elements in other embodiments. Components of the baseband circuitry can be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 604 and the application circuitry 602 can be implemented together such as, for example, on a system on a chip (SOC).

[0074] In some embodiments, the baseband circuitry 604 can provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 604 can support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 604 is configured to support radio communications of more than one wireless protocol can be referred to as multi-mode baseband circuitry.

[0075] RF circuitry 606 can enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 606 can include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 606 can include a receive signal path which can include circuitry to down-convert RF signals received from the FEM circuitry 608 and provide baseband signals to the baseband circuitry 604. RF circuitry 606 can also include a transmit signal path which can include circuitry to up- convert baseband signals provided by the baseband circuitry 604 and provide RF output signals to the FEM circuitry 608 for transmission.

[0076] In some embodiments, the RF circuitry 606 can include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 606 can include mixer circuitry 606a, amplifier circuitry 606b and filter circuitry 606c. The transmit signal path of the RF circuitry 606 can include filter circuitry 606c and mixer circuitry 606a. RF circuitry 606 can also include synthesizer circuitry 606d for synthesizing a frequency 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 can be configured to down-convert RF signals received from the FEM circuitry 608 based on the synthesized frequency provided by synthesizer circuitry 606d. The amplifier circuitry 606b can be configured to amplify the down-converted signals and the filter circuitry 606c can be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals can be provided to the baseband circuitry 604 for further processing. In some embodiments, the output baseband signals can be zero- frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 606a of the receive signal path can comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0077] In some embodiments, the mixer circuitry 606a of the transmit signal path can be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 606d to generate RF output signals for the FEM circuitry 608. The baseband signals can be provided by the baseband circuitry 604 and can be filtered by filter circuitry 606c. The filter circuitry 606c can include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[0078] In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path can include two or more mixers and can be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path can include two or more mixers and can be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a can be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path can be configured for super-heterodyne operation.

[0079] In some embodiments, the output baseband signals and the input baseband signals can be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals can be digital baseband signals. In these alternate embodiments, the RF circuitry 606 can include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 604 can include a digital baseband interface to communicate with the RF circuitry 606.

[0080] In some dual-mode embodiments, a separate radio IC circuitry can be provided for processing signals for each spectrum, although the scope of the

embodiments is not limited in this respect.

[0081] In some embodiments, the synthesizer circuitry 606d can be a fractional-N synthesizer or a fractional N/N+8 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers can be suitable. For example, synthesizer circuitry 606d can be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[0082] The synthesizer circuitry 606d can be configured to synthesize an output frequency for use by the mixer circuitry 606a of the RF circuitry 606 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 606d can be a fractional N/N+8 synthesizer.

[0083] In some embodiments, frequency input can be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input can be provided by either the baseband circuitry 604 or the applications processor 602 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) can be determined from a look-up table based on a channel indicated by the applications processor 602.

[0084] Synthesizer circuitry 606d of the RF circuitry 606 can include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some

embodiments, the divider can be a dual modulus divider (DMD) and the phase accumulator can be a digital phase accumulator (DPA). In some embodiments, the DMD can be configured to divide the input signal by either N or N+8 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL can 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 can be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0085] In some embodiments, synthesizer circuitry 606d can be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency can be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency can be a LO frequency (f_Lo)- In some embodiments, the RF circuitry 606 can include an IQ/polar converter.

[0086] FEM circuitry 608 can include a receive signal path which can include circuitry configured to operate on RF signals received from one or more antennas 680, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 606 for further processing. FEM circuitry 608 can also include a transmit signal path which can include circuitry configured to amplify signals for transmission provided by the RF circuitry 606 for transmission by one or more of the one or more antennas 680.

[0087] In some embodiments, the FEM circuitry 608 can include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry can include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry can include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 606). The transmit signal path of the FEM circuitry 608 can include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 606), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 680.

[0088] In some embodiments, the UE device 600 can include additional elements such as, for example, memory/storage, display, camera, sensor, and/or input/output (I/O) interface.

[0089] Examples herein can include subject matter such as a method, means for performing acts or blocks of the method, at least one machine-readable medium including executable instructions that, when performed by a machine (e.g., a processor with memory or the like) cause the machine to perform acts of the method or of an apparatus or system for concurrent communication using multiple communication technologies according to embodiments and examples described.

[0090] Example 1 is an architecture configured to be employed within one or more user evolved node Bs (eNodeBs). The architecture includes frame logic and a transmit component. The frame logic is configured to generate a frame using time division duplexing (TDD) and a frame having a plurality of subframes. The subframes include a special subframe having a downlink/uplink proportional configuration. The transmit component is configured to transmit the frame as part of a transmit signal using time division duplexing (TDD).

[0091] Example 2 includes the subject matter of Example 1 , including or omitting optional elements, where the special subframe has downlink and uplink fields in accordance with the downlink/uplink proportional configuration.

[0092] Example 3 includes the subject matter of any one of Examples 1-2, including or omitting optional elements, where the special subframe includes one or more guard periods separating the downlink and uplink fields.

[0093] Example 4 includes the subject matter of any one of Examples 1-3, including or omitting optional elements, where the guard periods have a length based on adjacent portions of the special subframe.

[0094] Example 5 includes the subject matter of any one of Examples 1-4, including or omitting optional elements, where the guard periods have a length equal to a transmitter transient period upon transitions, wherein the transitions include a transition from an uplink field to a downlink field.

[0095] Example 6 includes the subject matter of any one of Examples 1-5, including or omitting optional elements, where the uplink fields and the downlink fields have varied lengths.

[0096] Example 7 includes the subject matter of any one of Examples 1-6, including or omitting optional elements, where a guard period after and adjacent to a downlink field and prior to and adjacent to an uplink field is set to a length of zero.

[0097] Example 8 includes the subject matter of any one of Examples 1-7, including or omitting optional elements, further including retransmission logic configured to determine retransmission parameters based on system parameters. [0098] Example 9 includes the subject matter of any one of Examples 1-8, including or omitting optional elements, where the system parameters include a number of subframes, a transmitter processing delay and a receiver processing delay.

[0099] Example 10 includes the subject matter of any one of Examples 1-9, including or omitting optional elements, where the retransmission parameters include a downlink ACK offset, a downlink retransmission offset, an uplink ACK offset and an uplink retransmission offset.

[00100] Example 11 is an architecture configured to be employed within one or more evolved node Bs (eNodeBs). The architecture includes frame logic, retransmission logic, and a transmit component. The frame logic is configured to generate a frame having a downlink/uplink proportional configuration and associated with system parameters. The system parameters include a number of subframes and a processing delay. The retransmission logic is configured to determine retransmission parameters based on the system parameters and to perform retransmission based on the determined retransmission parameters. The transmit component is configured to transmit the frame and retransmitted subframes as part of a transmit signal using time division duplexing (TDD).

[00101] Example 12 includes the subject matter of Examples 11 , including or omitting optional elements, where the retransmission parameters include a downlink ACK offset, which is based at least partially on a receiver processing delay.

[00102] Example 13 includes the subject matter of any one of Examples 11-12, including or omitting optional elements, where the retransmission parameters include a downlink retransmission offset, which is at least partially based on a transmitter processing delay.

[00103] Example 14 includes the subject matter of any one of Examples 11-13, including or omitting optional elements, where the retransmission parameters include an uplink ACK offset, which is based at least partially on a transmitter processing delay.

[00104] Example 15 includes the subject matter of any one of Examples 11-14, including or omitting optional elements, where the retransmission parameters include an uplink retransmission offset, which is based at least partially on a receiver processing delay.

[00105] Example 16 includes the subject matter of any one of Examples 11-15, including or omitting optional elements, where the retransmission logic is configured to select the downlink/uplink proportional configuration from a plurality of frame

downlink/uplink proportional configurations.

[00106] Example 17 is one or more computer-readable media having instructions that, when executed, cause one or more user equipment (UEs) to perform operations. The operations cause the one or more UEs to select a downlink/uplink frame configuration from a plurality of frame configurations based on system parameters, configure lengths for downlink transmission fields, uplink transmission fields and guard periods in a plurality of subframes for a frame having the selected downlink/uplink frame

configuration, and determine retransmission parameters based on the system

parameters.

[00107] Example 18 includes the subject matter of Example 17, including or omitting optional elements, where the downlink/uplink frame configuration is selected according to a downlink/uplink ratio.

[00108] Example 19 includes the subject matter of any one of Examples 17-18, including or omitting optional elements, where the instructions further cause the eNodeB to retransmit subframes according to the determined retransmission parameters.

[00109] Example 20 includes the subject matter of any one of Examples 17- 9, including or omitting optional elements, where the selected downlink/uplink frame configuration includes a special frame having a downlink to uplink ratio of more than 90 percent.

[00110] Example 21 includes the subject matter of any one of Examples 17-20, including or omitting optional elements, where the guard periods are allocated a length based on prior and subsequent adjacent transmission fields.

[00111] Example 22 is an apparatus to be employed within an evolved node B

(eNodeB). The apparatus includes a means for selecting a downlink/uplink frame configuration from a plurality of frame configurations based on system parameters; a means for configuring frame lengths for downlink transmission fields, uplink

transmission fields and guard periods in a plurality of subframes for a frame having the selected downlink/uplink frame configuration; and a means for determining

retransmission parameters based on the system parameters.

[00112] The above description of illustrated embodiments of the subject disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the disclosed embodiments to the precise forms disclosed. While specific embodiments and examples are described herein for illustrative purposes, various modifications are possible that are considered within the scope of such embodiments and examples, as those skilled in the relevant art can recognize.

[00113] In this regard, while the disclosed subject matter has been described in connection with various embodiments and corresponding Figures, where applicable, it is to be understood that other similar embodiments can be used or modifications and additions can be made to the described embodiments for performing the same, similar, alternative, or substitute function of the disclosed subject matter without deviating therefrom. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but rather should be construed in breadth and scope in accordance with the appended claims below.

[00114] In particular regard to the various functions performed by the above described components or structures (assemblies, devices, circuits, systems, etc.), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component or structure which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the invention. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.

Claims

CLAIMS What is claimed is:

1. An architecture configured to be employed within one or more user evolved node Bs (eNodeBs), the architecture comprising:

frame logic configured to generate a frame using time division duplexing (TDD) and a frame having a plurality of subframes, wherein the subframes include a special subframe having a downlink/uplink proportional configuration; and

a transmit component configured to transmit the frame as part of a transmit signal using time division duplexing (TDD).

2. The architecture of claim 1 , wherein the special subframe has downlink and uplink fields in accordance with the downlink/uplink proportional configuration.

3. The architecture of claim 2, wherein the special subframe includes one or more guard periods separating the downlink and uplink fields.

4. The architecture of claim 3, wherein the guard periods have a length based on adjacent portions of the special subframe.

5. The architecture of claim 3, wherein the guard periods have a length equal to a transmitter transient period upon transitions, wherein the transitions include a transition from an uplink field to a downlink field.

6. The architecture of claim 3, wherein the uplink fields and the downlink fields have varied lengths.

7. The architecture of claim 3, wherein a guard period after and adjacent to a downlink field and prior to and adjacent to an uplink field is set to a length of zero.

8. The architecture of any one of claims 1-3, further comprising retransmission logic configured to determine retransmission parameters based on system parameters.

9. The architecture of claim 8, wherein the system parameters include a number of subframes, a transmitter processing delay and a receiver processing delay.

10. The architecture of claim 8, wherein the retransmission parameters include a downlink ACK offset, a downlink retransmission offset, an uplink ACK offset and an uplink retransmission offset.

11. An architecture configured to be employed within one or more evolved node Bs (eNodeBs), the architecture comprising:

frame logic configured to generate a frame having a downlink/uplink proportional configuration and associated with system parameters, wherein the system parameters include a number of subframes and a processing delay;

retransmission logic configured to determine retransmission parameters based on the system parameters and to perform retransmission based on the determined retransmission parameters; and

a transmit component configured to transmit the frame and retransmitted subframes as part of a transmit signal using time division duplexing (TDD).

12. The architecture of claim 11 , wherein the retransmission parameters include a downlink ACK offset, based at least partially on a receiver processing delay.

13. The architecture of claim 11 , wherein the retransmission parameters include a downlink retransmission offset, based at least partially on a transmitter processing delay.

14. The architecture of any one of claim 11-13, wherein the retransmission parameters include an uplink ACK offset, based at least partially on a transmitter processing delay.

15. The architecture of claim 14, wherein the retransmission parameters include an uplink retransmission offset, based at least partially on a receiver processing delay.

16. The architecture of claim 11 , where the retransmission logic is configured to select the downlink/uplink proportional configuration from a plurality of frame

downlink/uplink proportional configurations.

17. One or more computer-readable media having instructions that, when executed, cause an eNodeB to:

select a downlink/uplink frame configuration from a plurality of frame

configurations based on system parameters; configure lengths for downlink transmission fields, uplink transmission fields and guard periods in a plurality of subframes for a frame having the selected downlink/uplink frame configuration; and

determine retransmission parameters based on the system parameters.

18. The computer-readable media of claim 17, wherein the downlink/uplink frame configuration is selected according to a downlink/uplink ratio.

19. The computer-readable media of claim 17, where the instructions further cause the eNodeB to retransmit subframes according to the determined retransmission parameters.

20. The computer-readable media of any one of claims 7-19, wherein the selected downlink/uplink frame configuration includes a special frame having a downlink to uplink ratio of more than 90 percent.

21. The computer-readable media of any one of claims 17-19, wherein the guard periods are allocated a length based on prior and subsequent adjacent transmission fields.

22. An apparatus to be employed within an eNodeB, the apparatus comprising: a means for selecting a downlink/uplink frame configuration from a plurality of frame configurations based on system parameters;

a means for configuring frame lengths for downlink transmission fields, uplink transmission fields and guard periods in a plurality of subframes for a frame having the selected downlink/uplink frame configuration; and

a means for determining retransmission parameters based on the system parameters.