Patent Description:
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Examples of multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

Examples of telecommunication standards include Long Term Evolution (LTE) and LTE-Advanced (LTE-A), which include a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE-A is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology.

However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in multiple access technologies technology. For example, the spectrum allocated to wireless communication networks employing multiple access technology is being (or is expected to be) allocated in such a way that paired carriers, utilized in many existing frequency division duplex (FDD) systems, are either not available, or not available in matched bandwidth configurations. Accordingly, time division duplex (TDD) carriers are expected to be utilized in many future deployments for wireless communication systems. <CIT> describes a mixed numerology OFDM design.

Various aspects of the present disclosure provide a time division duplex (TDD) subframe structure that supports both a single interlace mode of operation and a multiple interlace mode of operation. In the single interlace mode of operation, control information, data information corresponding to the control information and acknowledgement information corresponding to the data information are included in a single subframe. In the multiple interlace mode of operation, at least one of the control information, the data information corresponding to the control information or the acknowledgement information corresponding to the data information is included in a different subframe. Both single and multiple interlace modes can be multiplexed together within the TDD subframe structure.

In one aspect, the disclosure provides a method of wireless communication in a wireless communication network for a scheduling entity to communicate with a set of one or more subordinate entities utilizing a time division duplex (TDD) carrier, in which the TDD carrier includes a plurality of subframes, each having a TDD subframe structure. The method includes: providing a single interlace mode of operation in which control information, data information and acknowledgement information corresponding to the data information are included in a single subframe; providing a multiple interlace mode of operation in which at least one of the control information, the data information or the acknowledgement information corresponding to the data information is included in a different subframe than other ones of the control information, the data information and the acknowledgement information corresponding to the data information; determining a respective scheduling mode for each subordinate entity in the set of subordinate entities, in which the respective scheduling mode includes the single interlace mode of operation or the multiple interlace mode operation; and scheduling transmissions between the scheduling entity and the set of subordinate entities by multiplexing the respective scheduling mode of each subordinate entity of the set of subordinate entities within the TDD subframe structure.

Another aspect of the disclosure provides a scheduling entity in a wireless communication network. The scheduling entity includes a processing system configured to provide a single interlace mode of operation in which control information, data information and acknowledgement information corresponding to the data information are included in a single subframe of a time division duplex (TDD) carrier utilizing a TDD subframe structure. The processing system is further configured to provide a multiple interlace mode of operation in which at least one of the control information, the data information or the acknowledgement information corresponding to the data information is included in a different subframe than other ones of the control information, the data information and the acknowledgement information corresponding to the data information. The processing system is further configured to determine a respective scheduling mode for each subordinate entity in a set of subordinate entities, in which the respective scheduling mode includes the single interlace mode of operation or the multiple interlace mode operation, and schedule transmissions between the scheduling entity and the set of subordinate entities by multiplexing the respective scheduling mode of each subordinate entity of the set of subordinate entities within the TDD subframe structure.

Another aspect of the disclosure provides a scheduling entity apparatus in a wireless communication network. The scheduling entity apparatus includes means for providing a single interlace mode of operation in which control information, data information and acknowledgement information corresponding to the data information are included in a single subframe of a time division duplex (TDD) carrier utilizing a TDD subframe structure, means for providing a multiple interlace mode of operation in which at least one of the control information, the data information or the acknowledgement information corresponding to the data information is included in a different subframe than other ones of the control information, the data information and the acknowledgement information corresponding to the data information, means for determining a respective scheduling mode for each subordinate entity in a set of subordinate entities, in which the respective scheduling mode includes the single interlace mode of operation or the multiple interlace mode operation, and means for scheduling transmissions between the scheduling entity and the set of subordinate entities by multiplexing the respective scheduling mode of each subordinate entity of the set of subordinate entities within the TDD subframe structure.

Another aspect of the disclosure provides a non-transitory computer-readable medium including code for providing a single interlace mode of operation in which control information, data information and acknowledgement information corresponding to the data information are included in a single subframe of a time division duplex (TDD) carrier utilizing a TDD subframe structure, code for providing a multiple interlace mode of operation in which at least one of the control information, the data information or the acknowledgement information corresponding to the data information is included in a different subframe than other ones of the control information, the data information and the acknowledgement information corresponding to the data information, code for determining a respective scheduling mode for each subordinate entity in the set of subordinate entities, in which the respective scheduling mode includes the single interlace mode of operation or the multiple interlace mode operation, and code for scheduling transmissions between the scheduling entity and the set of subordinate entities by multiplexing the respective scheduling mode of each subordinate entity of the set of subordinate entities within the TDD subframe structure.

Examples of additional aspects of the disclosure follow. In some aspects, the TDD subframe structure includes at least a control portion, a data portion and an acknowledgement portion. In some aspects, in the multiple interlace mode of operation, the method further includes transmitting the control information in the control portion of a first subframe, transmitting the data information corresponding to the control information in the data portion of the first subframe, receiving the acknowledgement information corresponding to the data information in the acknowledgement portion of the first subframe, and retransmitting at least part of the data information in the data portion of an additional subframe subsequent to the first subframe, the first subframe and the additional subframe separated in time by at least one intermediate subframe.

In some aspects, in the multiple interlace mode of operation, the method further includes transmitting the control information in the control portion of a first subframe, transmitting the data information corresponding to the control information in the data portion of the first subframe, and receiving the acknowledgement information corresponding to the data information in the acknowledgement portion of a second subframe subsequent to the first subframe. In some aspects, in the multiple interlace mode of operation, the method further includes retransmitting at least part of the data information in the data portion of a third subframe subsequent to the second subframe. In some aspects, the third subframe and the second subframe are separated in time by at least one intermediate subframe.

In some aspects, in the multiple interlace mode of operation, the method further includes transmitting the control information in the control portion of a first subframe, transmitting the data information corresponding to the control information in the data portion of a second subframe subsequent to the first subframe, and receiving the acknowledgement information corresponding to the data information in the acknowledgement portion of the second subframe. In some aspects, transmitting the control information further includes transmitting the control information in both the control portion and the data portion of the first subframe.

In some aspects, in the multiple interlace mode of operation, the method further includes transmitting the control information in the control portion of a first subframe, transmitting the data information corresponding to the control information in the data portion of the first subframe, and receiving the acknowledgement information corresponding to the data information in the acknowledgement portion of the first subframe and at least one additional subframe subsequent to the first subframe. In some aspects, in the multiple interlace mode of operation, the method further includes transmitting the control information in the control portion of a downlink-centric subframe, transmitting the data information corresponding to the control information in the data portion of the downlink-centric subframe, and receiving the acknowledgement information corresponding to the data information in a data portion of an uplink-centric subframe subsequent to the downlink-centric subframe. In some aspects, receiving the acknowledgement information further includes receiving additional acknowledgement information corresponding to additional data information in the data portion of the uplink-centric subframe. In some aspects, in the multiple interlace mode of operation, the method further includes using coding to provide the acknowledgement information corresponding to the data information across one or more subframes.

In order to illustrate some of the entities or devices described throughout the present disclosure, <FIG> is a diagram illustrating a generalized example of a wireless communication network <NUM>. In this example, the wireless communication network <NUM> is divided into a number of cellular regions (cells) <NUM>. In the context of a multiple access network, channel resources may generally be scheduled, and each entity may be synchronous. That is, each node utilizing the network may coordinate its usage of the resources such that transmissions are only made during the allocated portion of the frame, and the time of each allocated portion is synchronized among the different nodes. One node in each cellular region <NUM>/<NUM> acts as a scheduling entity.

Each scheduling entity <NUM>/<NUM> may be a base station or access point, or a user equipment (UE) <NUM> in a device-to-device (D2D) and/or mesh network. The scheduling entity <NUM>/<NUM> manages the resources on the carrier and assigns resources to other users of the channel, including subordinate entities, such as one or more UEs <NUM> in the cellular network <NUM>. The scheduling entities <NUM> are responsible for all radio related functions including radio bearer control, admission control, mobility control, scheduling, security, and connectivity to a centralized controller and/or gateway. There is no centralized controller in this example of a network <NUM>, but a centralized controller may be used in alternative configurations.

One or more lower power class scheduling entities <NUM> may have a cellular region <NUM> that overlaps with one or more other cellular regions (cells) <NUM>. The lower power class scheduling entity <NUM> may be a femto cell, pico cell, micro cell, remote radio head, or in some instances, another UE <NUM>. The macro scheduling entities <NUM> are each assigned to a respective cell <NUM> and are configured to provide an access point to a core network for all the UEs <NUM> in the cells <NUM>.

The modulation and multiple access scheme employed by the network <NUM> may vary depending on the particular telecommunications standard being deployed. In some radio access networks, such as those defined in LTE standards, orthogonal frequency division multiplexing (OFDM) is used on the downlink (DL) and single carrier frequency division multiple access (SC-FDMA) is used on the uplink (UL) to support both frequency division duplexing (FDD) and time division duplexing (TDD). As those skilled in the art will readily appreciate from the detailed description to follow, the various concepts presented herein are well suited for various applications including telecommunication standards employing other modulation and multiple access techniques. By way of example, these concepts may be employed in <NUM>, LTE, or Evolution-Data Optimized (EV-DO). EV-DO is an air interface standard promulgated by the 3rd Generation Partnership Project <NUM> (3GPP2) as part of the CDMA2000 family of standards and employs CDMA to provide broadband Internet access to mobile stations. These concepts may also be extended to Universal Terrestrial Radio Access (UTRA) employing Wideband-CDMA (W-CDMA) and other variants of CDMA, such as TD-SCDMA; Global System for Mobile Communications (GSM) employing TDMA; Evolved UTRA (E-UTRA), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from the 3GPP organization. CDMA2000 is described in documents from the 3GPP2 organization. The actual wireless communication standard and the multiple access technology employed will depend on the specific application and the overall design constraints imposed on the system.

The scheduling entities <NUM> may have multiple antennas supporting MIMO technology. The use of MIMO technology enables the scheduling entities <NUM> to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data simultaneously on the same frequency. The data steams may be transmitted to a single UE <NUM> to increase the data rate or to multiple UEs <NUM> to increase the overall system capacity. This is achieved by spatially precoding each data stream (i.e., applying a scaling of an amplitude and a phase) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink (DL). The spatially precoded data streams arrive at the UE(s) <NUM> with different spatial signatures, which enables each of the UE(s) <NUM> to recover the one or more data streams destined for that UE <NUM>. On the uplink (UL), each UE <NUM> transmits a spatially precoded data stream, which enables the scheduling entity <NUM> to identify the source of each spatially precoded data stream.

Spatial multiplexing is generally used when channel conditions are good. When channel conditions are less favorable, beamforming may be used to focus the transmission energy in one or more directions. This may be achieved by spatially precoding the data for transmission through multiple antennas. To achieve good coverage at the edges of the cell, a single stream beamforming transmission may be used in combination with transmit diversity.

Certain aspects of a wireless communication network described herein may relate to a system supporting OFDM on the DL. OFDM is a spread-spectrum technique that modulates data over a number of subcarriers within an OFDM symbol. The subcarriers are spaced apart at precise frequencies. The spacing provides orthogonality that enables a receiver to recover the data from the subcarriers. In the time domain, a guard interval (e.g., cyclic prefix) may be added to each OFDM symbol to combat inter-OFDM-symbol interference. In some examples, the UL may use SC-FDMA in the form of a Discrete Fourier Transform (DFT)-spread OFDM signal to compensate for high peak-to-average power ratio (PAPR). However, those of ordinary skill in the art will recognize that any suitable modulation and multiple access scheme may be utilized for uplink and downlink communication.

Referring now to <FIG>, a block diagram illustrates an exemplary scheduling entity <NUM> in wireless communication with a plurality of subordinate entities <NUM>. The scheduling entity <NUM> transmits downlink data channel(s) <NUM> and downlink control channel(s) <NUM>, while the subordinate entities <NUM> transmit uplink data channel(s) <NUM> and uplink control channel(s) <NUM>. Of course, the channels illustrated in <FIG> are not necessarily all of the channels that may be utilized between a scheduling entity <NUM> and subordinate entities <NUM>, and those of ordinary skill in the art will recognize that other channels may be utilized in addition to those illustrated, such as other control and feedback channels.

In accordance with aspects of the present disclosure, the term downlink (DL) may refer to a point-to-multipoint transmission originating at the scheduling entity <NUM>. In addition, the term uplink (UL) may refer to a point-to-point transmission originating at a subordinate entity <NUM>.

Broadly, the scheduling entity <NUM> is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink transmissions and, in some examples, uplink data <NUM> from one or more subordinate entities <NUM> to the scheduling entity <NUM>. A scheduling entity <NUM> may be, or may reside within, a base station, a network node, a user equipment (UE), an access terminal, or any suitable node or peer in a wireless communication network.

Broadly, the subordinate entity <NUM> is a node or device that receives scheduling control information, including but not limited to scheduling grants, synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity <NUM>. A subordinate entity may be, or may reside within, a base station, a network node, a UE, an access terminal, or any suitable node or peer in a wireless communication network.

As illustrated in <FIG>, the scheduling entity <NUM> may transmit downlink data <NUM> to one or more subordinate entities <NUM>. In addition, the subordinate entities <NUM> may transmit uplink data <NUM> to the scheduling entity <NUM>. In accordance with aspects of the disclosure, the uplink data <NUM> and/or downlink data <NUM> may be transmitted in transmission time intervals (TTIs). As used herein, the term TTI refers to the period in which a block of data, corresponding to the smallest collection of symbols to be processed at the Media Access Control (MAC) layer and above, is transferred by the physical layer onto the radio interface. In accordance with aspects of the disclosure, a TTI is equal to the duration of a subframe. Thus, as further used herein, the term subframe refers to an encapsulated set of information sent within a single TTI that is capable of being independently decoded. In various aspects, multiple subframes are grouped together to form a single frame. For example, in LTE, the TTI (subframe duration) is set to <NUM>, whereas the frame duration is set to <NUM>, corresponding to <NUM> subframes. However, within the scope of the present disclosure, a subframe may have a duration of <NUM>, <NUM>, <NUM>, or any suitable duration. Similarly, any suitable number of subframes may occupy a frame. Frames are generally utilized by upper Open Systems Interconnection (OSI) layers for synchronization and other purposes.

In one example, the scheduling entity <NUM> may multiplex downlink data for a set of subordinate entities (i.e., two or more subordinate entities) within a single subframe. For example, the scheduling entity <NUM> may multiplex downlink data to the set of subordinate entities using time division multiplexing, frequency division multiplexing (e.g., OFDM), code division multiplexing, and/or any suitable multiplexing scheme known to those of ordinary skill in the art. Likewise, any suitable multiple access scheme may be utilized to combine uplink data from multiple subordinate entities <NUM> within a single subframe.

The scheduling entity <NUM> may further broadcast downlink control channel(s) <NUM> to one or more subordinate entities <NUM>. The downlink control channel(s) <NUM> may include in some examples a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH) and/or any other control channels or pilots, such as the Channel State Information - Reference Signal (CSI-RS) pilot. In still a further example, the downlink control channel(s) <NUM> may include acknowledgement information (e.g., acknowledged (ACK)/not acknowledged (NACK) packets) indicating whether the uplink data <NUM> in one or more subframes was received correctly at the scheduling entity <NUM>. For example, a data packet may include verification bits, such as a checksum and/or a cyclic redundancy check (CRC). Accordingly, a device receiving a data packet may receive and decode the data packet and verify the integrity of the received and decoded packet in accordance with the verification bits. When the verification succeeds, a positive acknowledgment (ACK) may be transmitted; whereas when the verification fails, a negative acknowledgment (NACK) may be transmitted.

Furthermore, each of the subordinate entities <NUM> may transmit uplink control channel(s) <NUM> to the scheduling entity <NUM>. The uplink control channel(s) <NUM> may include in some examples a physical uplink control channel (PUCCH), random access channel (RACH), scheduling request (SR), sounding reference signal (SRS), channel quality indicator (CQI), channel state feedback information, buffer status information, or any other suitable control information or signaling. In an aspect of the disclosure, the uplink control channel(s) <NUM> may include a request for the scheduling entity <NUM> to schedule uplink transmissions. Here, in response to the request transmitted on the uplink control channel(s) <NUM>, the scheduling entity <NUM> may transmit in the downlink control channel(s) <NUM> information that may schedule the TTI with uplink packets. In still a further example, the uplink control channel(s) <NUM> may include acknowledgement information (e.g., acknowledged (ACK)/not acknowledged (NACK) packets) indicating whether the downlink data <NUM> in one or more subframes was received correctly at the subordinate entity <NUM>.

<FIG> is a conceptual diagram illustrating an example of a hardware implementation for a scheduling entity <NUM> employing a processing system <NUM>. In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system <NUM> that includes one or more processors <NUM>.

In various aspects of the disclosure, the scheduling entity <NUM> may be any suitable radio transceiver apparatus, and in some examples, may be embodied in a base station (BS), a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B, an eNode B (eNB), mesh node, relay, or some other suitable terminology. Within the present document, a base station may be referred to as a scheduling entity, indicating that the base station provides scheduling information to one or more subordinate entities. Such a base station may provide a wireless access point to a core network for any number of subordinate entities.

In other examples, the scheduling entity <NUM> may be embodied by a wireless user equipment (UE). Examples of a UE include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a notebook, a netbook, a smartbook, a personal digital assistant (PDA), a satellite radio, a global positioning system (GPS) device, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, an entertainment device, a vehicle component, a wearable computing device (e.g., a smart watch, a health or fitness tracker, etc.), an appliance, a sensor, a vending machine, or any other similar functioning device. The UE may also be referred to by those skilled in the art as a mobile station (MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. Within the present document, a UE may be referred to either as a scheduling entity, or a subordinate entity. That is, in various aspects of the present disclosure, a wireless UE may operate as a scheduling entity providing scheduling information to one or more subordinate entities, or may operate as a subordinate entity, operating in accordance with scheduling information provided by a scheduling entity.

Examples of processors <NUM> include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. That is, the processor <NUM>, as utilized in a scheduling entity <NUM>, may be used to implement any one or more of the processes described below.

In this example, the processing system <NUM> may be implemented with a bus architecture, represented generally by the bus <NUM>. The bus <NUM> may include any number of interconnecting buses and bridges depending on the specific application of the processing system <NUM> and the overall design constraints. The bus <NUM> links together various circuits including one or more processors (represented generally by the processor <NUM>), a memory <NUM>, and computer-readable media (represented generally by the computer-readable medium <NUM>). The bus <NUM> may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface <NUM> provides an interface between the bus <NUM> and a transceiver <NUM>. The transceiver <NUM> provides a means for communicating with various other apparatus over a transmission medium. Depending upon the nature of the apparatus, a user interface <NUM> (e.g., keypad, display, speaker, microphone, joystick) may also be provided.

The computer-readable medium <NUM> may also be used for storing data that is manipulated by the processor <NUM> when executing software.

In some aspects of the disclosure, the processor <NUM> may include resource assignment and subframe generation circuitry <NUM>, configured to generate, schedule, and modify a resource assignment or grant of time-frequency resources. For example, the resource assignment and subframe control circuitry <NUM> may generate one or more time division duplex (TDD) subframes, each including time-frequency resources assigned to carry data and/or control information to and/or from multiple subordinate entities. The resource assignment and subframe generation circuitry <NUM> may operate in coordination with resource assignment and subframe generation software <NUM>.

The processor <NUM> may further include downlink (DL) data and control channel generation and transmission circuitry <NUM>, configured to generate and transmit downlink data and control channels. The DL data and control channel generation and transmission circuitry <NUM> may operate in coordination with the resource assignment and subframe control circuitry <NUM> to schedule the DL data and/or control information and to place the DL data and/or control information onto a time division duplex (TDD) carrier within one or more subframes generated by the resource assignment and subframe generation circuitry <NUM> in accordance with the resources assigned to the DL data and/or control information. The DL data and control channel generation and transmission circuitry <NUM> may further operate in coordination with DL data and control channel generation and transmission software <NUM>.

The processor <NUM> may further include uplink (UL) data and control channel reception and processing circuitry <NUM>, configured to receive and process uplink control channels and uplink data channels from one or more subordinate entities. In some examples, the UL data and control channel reception and processing circuitry <NUM> may be configured to receive scheduling requests from one or more subordinate entities, the scheduling requests being configured to request a grant of time-frequency resources for uplink user data transmissions. In other examples, the UL data and control channel reception and processing circuitry <NUM> may be configured to receive and process acknowledgement information (e.g., acknowledged/not acknowledged packets) from one or more subordinate entities. The UL data and control channel reception and processing circuitry <NUM> may operate in coordination with the resource assignment and subframe generation circuitry <NUM> to schedule UL data transmissions, DL data transmissions and/or DL data retransmissions in accordance with the received UL control channel information. The UL data and control channel reception and processing circuitry <NUM> may further operate in coordination with UL data and control channel reception and processing software <NUM>.

The processor <NUM> may further include interlace mode configuration circuitry <NUM>, configured for providing at least a single interlace mode of operation, in which control, data and acknowledgement information is self-contained within a single TTI (or TDD subframe), and a multiple interlace mode of operation, in which the control, data and acknowledgement information are contained within two or more TTIs (or TDD subframes) in an interlaced manner.

In the single interlace mode of operation, a self-contained TDD subframe structure is utilized by the resource assignment and subframe control circuitry <NUM> to generate one or more self-contained subframes. In each self-contained subframe, the control/scheduling information provides control/scheduling for all of the data packets within the subframe and the acknowledgement information includes acknowledgement/not acknowledgement (ACK/NACK) signals for all of the data packets within the subframe. Therefore, the self-contained subframe structure may include transmissions in both the uplink and the downlink directions.

In some examples, the self-contained TDD subframe structure includes DL control (scheduling) information, DL data information corresponding to the scheduling information and UL acknowledgement information corresponding to the data information. In other examples, the self-contained subframe structure includes DL control (scheduling) information, UL data information corresponding to the scheduling information and DL acknowledgement information corresponding to the data information.

In an aspect of the disclosure, a hybrid automatic repeat request (HARQ) retransmission scheme is used to retransmit data incorrectly received. Although the single interlace mode supports single HARQ interlace processing at the physical layer to enable high data rates in extreme bandwidth cases with a reasonable HARQ buffer cost, when the throughput of a subordinate entity is not at peak and/or when there is limited link budget, the processing timeline may be too tight for the subordinate entity to turn around HARQ in the same self-contained subframe. For example, when the subordinate entity is located at the edge of the cell, there may be limited downlink control and uplink ACK link budgets due to limited bandwidth on the downlink and limited symbol duration on the uplink and downlink. These link budget limitations may prevent the subordinate entity from returning the ACK/NACK within the same subframe as data reception.

Processing and/or power constraints at the scheduling entity may also prevent the scheduling entity from completing retransmissions to one or more subordinate entities in the next subframe. For example, scheduling updates for the next subframe based on ACK/NACK signals received in a current subframe may require fast processing at the scheduling entity. If there is not sufficient time to decode all of the ACK/NACK signals before the next subframe, the scheduling entity may not be able to schedule all of the necessary retransmissions in the next subframe.

Therefore, to allow for longer processing time at the scheduling entity and/or subordinate entity, the interlace mode configuration circuitry <NUM> may further provide a multiple interlace mode of operation. In the multiple interlace mode of operation, two or more TDD subframes are utilized by the resource assignment and subframe generation circuitry <NUM> to transmit the control, data (or retransmitted data) and acknowledgement information. In various aspects of the disclosure, the multiple interlace mode enables at least one of the control, data, or ACK information to be transmitted in an interlaced manner between two or more TDD subframes. In some examples, the TDD subframe structure utilized in the multiple interlace mode of operation may be the same TDD subframe structure utilized in the single interlace mode of operation. However, the TDD subframe structure may not be entirely self-contained, such that one or more of the control, data, or ACK information may be transmitted in a different subframe.

In some examples, the multiple interlace mode of operation enables data retransmission to be delayed one or more subframes. Thus, instead of scheduling retransmissions in back-to-back subframes, retransmissions may be scheduled in subsequent subframes (e.g., every other subframe or any other delayed scheduling configuration). In other examples, the ACK/NACK information may be delayed one or more subframes (e.g., the ACK/NACK portion in a particular subframe may correspond to data transmitted in a previous subframe). In still other examples, the control information may be prescheduled, such that the control portion of a particular subframe may correspond to data transmitted in a subsequent subframe. Similar multiple interlace mode arrangements may be implemented for UL data transmissions and retransmissions. The interlace mode configuration circuitry <NUM> may operate in coordination with interlace mode configuration software <NUM>.

The processor <NUM> may further include interlace mode assignment circuitry <NUM>, configured to assign a scheduling mode selected from the single and multiple interlace modes to each subordinate entity. The scheduling mode assigned to a particular subordinate entity may depend on various factors, such as the throughput, buffer (e.g., hybrid automatic repeat request (HARQ) buffer size), and/or latency requirements of the subordinate entity, the power consumption and/or processing speed of the scheduling entity and/or the subordinate entity and the link budget of the uplink/downlink. The interlace mode assignment circuitry <NUM> may operate in coordination with interlace mode assignment software <NUM>.

In an exemplary operation, the interlace mode assignment circuitry <NUM> may assign the single interlace mode of operation or the multiple interlace mode of operation to each subordinate entity for a current subframe based on the processing resources and/or constraints of the scheduling entity and/or subordinate entities, and in coordination with the interlace mode configuration circuitry <NUM>, provide the parameters defining the assigned mode(s) of operation to the resource assignment and subframe generation circuitry <NUM> for generation of the current subframe. The resource assignment and subframe generation circuitry <NUM> may multiplex both single interlace subordinate entities and multiple interlace subordinate entities within the current TDD subframe.

The resource assignment and subframe generation circuitry <NUM> may further determine a TDD subframe structure for the current subframe. In some examples, the resource assignment and subframe generation circuitry <NUM> may determine whether the current subframe should include primarily uplink (UL) data information or primarily downlink (DL) data information. When the resource assignment and subframe generation circuitry <NUM> determines that the current subframe should include primarily DL data information, the resource assignment and subframe generation circuitry <NUM> provides a TDD subframe structure that includes a DL control (scheduling) portion, a DL data portion and an UL acknowledgement portion. When the resource assignment and subframe generation circuitry <NUM> determines that the current subframe should include primarily UL data information, the resource assignment and subframe generation circuitry <NUM> provides a TDD subframe structure that includes a DL control (scheduling) portion, an UL data portion and a DL acknowledgement portion. In the single interlace mode of operation, the TDD subframe structure is self-contained. However, in the multiple interlace mode of operation, the TDD subframe structure may enable at least one of the control, data, or ACK information to be transmitted in an interlaced manner between two or more TDD subframes.

Based on the subframe structure and selected modes of operation for each subordinate entity for the current subframe, the DL data and control channel generation and transmission circuitry <NUM> may populate the current subframe with control and/or data by preparing the control and/or data information in memory <NUM> and scheduling the control and/or data information via the resource assignment and subframe generation circuitry <NUM> for transmission according to the subframe structure and respective interlace modes of each subordinate entity. The DL data and control channel generation and transmission circuitry <NUM> may further coordinate with the UL data and control reception and processing circuitry <NUM> to generate the current subframe, as described below.

In an aspect of the disclosure, when the subframe structure includes a DL data portion, the DL data and control channel generation and transmission circuitry <NUM> may include DL control (scheduling) information in the control portion and DL data information in the data portion of the subframe. For example, the DL data and control channel generation and transmission circuitry <NUM> may include DL control (scheduling) information by preparing the control (scheduling) information in memory <NUM> and loading the control (scheduling) information from memory <NUM> into the DL control portion of the subframe. The DL data and control channel generation and transmission circuitry <NUM> may further include DL data information corresponding to the control information included in the current subframe (e.g., in the single interlace mode of operation) or in a previous subframe (e.g., in the multiple interlace mode of operation) by preparing the DL data information in memory <NUM> and loading DL data information from memory <NUM> into the DL data portion of the subframe. The control (scheduling) information may include control (scheduling) information for new DL data packets and retransmitted DL data packets. As an example, the DL data and control channel generation and transmission circuitry <NUM> may further carry hybrid automatic repeat request (HARQ) configuration information within the control (scheduling) information for retransmitted DL data packets by preparing the HARQ configuration information in memory <NUM> and loading the HARQ configuration information from memory <NUM> into the DL control portion of the current subframe. The UL data and control channel reception and processing circuitry <NUM> may then include acknowledgement information in the acknowledgement portion of the current subframe by receiving and processing ACK/NACK packets sent from one or more subordinate entities in the current subframe. The ACK/NACK packets may correspond to the DL data packets included in the current subframe (e.g., in the single interlace mode of operation) or in a previous subframe (e.g., in the multiple interlace mode of operation).

In an aspect of the disclosure in which the subframe structure includes an UL data portion, the DL data and control channel generation and transmission circuitry <NUM> may include DL control (scheduling) information in the control portion of the current subframe by preparing the DL control (scheduling) information in memory <NUM> and loading the control (scheduling) information from memory <NUM> into the DL control portion. The UL data and control channel reception and processing circuitry <NUM> may then include UL data information in the data portion of the current subframe by receiving and processing the UL data information sent from one or more subordinate entities. The UL data information may correspond to the control information included in the current subframe (e.g., in the single interlace mode of operation) or in a previous subframe (e.g., in the multiple interlace mode of operation). The DL data and control channel generation and transmission circuitry <NUM> may then include acknowledgement information corresponding to UL data information received in the current subframe (e.g., in the single interlace mode of operation) or in a previous subframe (e.g., in the multiple interlace mode of operation) by preparing the acknowledgement information (ACK/NACK packets) in memory <NUM> and loading the ACK/NACK packets from memory <NUM> into the acknowledgement portion of the current subframe.

The processor <NUM> may further include modulation and coding configuration circuitry <NUM>, configured for determining a modulation and coding scheme (MCS) to utilize for downlink transmissions and/or a MCS for a subordinate entity to utilize for uplink transmissions. The modulation and coding configuration circuitry <NUM> may operate in coordination with modulation and coding configuration software <NUM>.

One or more processors <NUM> in the processing system may execute software. The software may reside on a computer-readable medium <NUM>. The computer-readable medium <NUM> may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD)), a smart card, a flash memory device (e.g., a card, a stick, or a key drive), a random access memory (RAM), a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium <NUM> may reside in the processing system <NUM>, external to the processing system <NUM>, or distributed across multiple entities including the processing system <NUM>. The computer-readable medium <NUM> may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

<FIG> is a conceptual diagram illustrating an example of a hardware implementation for an exemplary subordinate entity <NUM> employing a processing system <NUM>. In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system <NUM> that includes one or more processors <NUM>.

The processing system <NUM> may be substantially the same as the processing system <NUM> illustrated in <FIG>, including a bus interface <NUM>, a bus <NUM>, memory <NUM>, a processor <NUM>, and a computer-readable medium <NUM>. Furthermore, the subordinate entity <NUM> may include a user interface <NUM> and a transceiver <NUM> substantially similar to those described above in <FIG>. The processor <NUM>, as utilized in a subordinate entity <NUM>, may be used to implement any one or more of the processes described below.

In some aspects of the disclosure, the processor <NUM> may include uplink (UL) data and control channel generation and transmission circuitry <NUM>, configured to generate and transmit uplink data on an UL data channel, and to generate and transmit uplink control/feedback/acknowledgement information on an UL control channel. The UL data and control channel generation and transmission circuitry <NUM> may operate in coordination with UL data and control channel generation and transmission software <NUM>. The processor <NUM> may further include downlink (DL) data and control channel reception and processing circuitry <NUM>, configured for receiving and processing downlink data on a data channel, and to receive and process control information on one or more downlink control channels. In some examples, received downlink data and/or control information may be temporarily stored in a data buffer <NUM> within memory <NUM>. The DL data and control channel generation and transmission circuitry <NUM> may operate in coordination with DL data and control channel generation and transmission software <NUM>.

The processor <NUM> may further include interlace mode determination circuitry <NUM>, configured for requesting and/or determining an interlace mode assigned to the subordinate entity. In an aspect of the disclosure, the interlace mode determination circuitry <NUM> may request a multiple interlace mode of operation when the throughput of the subordinate entity is not at peak and/or when there is limited link budget. The interlace mode determination circuitry <NUM> may operate in coordination with the interlace mode determination software <NUM>.

<FIG> illustrates exemplary structures of TDD subframes <NUM> and <NUM>. The TDD subframes <NUM> and <NUM> may have a fixed duration (t), but may also be configurable and determined during network deployment and/or may be updated through control messages or system messages. In one example, the duration of the TDD subframe <NUM> may be <NUM>. Of course, any suitable subframe duration may be utilized within the scope of the present disclosure.

A transmitter-scheduled subframe, referred to herein as a downlink TTI subframe or DL-centric subframe <NUM>, may be used to carry downlink control and data information to one or more subordinate entities, which may be a UEs for example, and also to receive acknowledgement information (e.g., ACK/NACK signals) from the subordinate entity or entities. Thus, each DL-centric subframe includes both DL transmissions and UL transmissions and is divided with respect to time (t) into DL transmission and UL transmission portions. A receiver-scheduled subframe, referred to herein as an uplink TTI subframe or UL-centric subframe <NUM>, may be used to receive downlink control information from the scheduling entity, transmit uplink data to a scheduling entity, and receive a downlink ACK/NACK signal for the transmitted data from the scheduling entity. Thus, each UL-centric subframe <NUM> also includes both DL transmissions and UL transmissions and is divided with respect to time (t) into DL transmission and UL transmission portions.

In the example of the DL-centric subframe <NUM> shown in <FIG>, the DL transmission portions include a control portion <NUM> and a data portion <NUM>, and the UL transmission portions include an acknowledgement (ACK/NACK) portion <NUM>. Therefore, within the subframe structure of <FIG>, the scheduling entity first has an opportunity to transmit control/scheduling information in the control portion <NUM>, and then an opportunity to transmit data in the DL data portion <NUM>. Following a guard period (GP) portion <NUM>, the scheduling entity has an opportunity to receive acknowledged (ACK)/not acknowledged (NACK) signals (ACK/NACK packets) from subordinate entities using the carrier. This frame structure is downlink-centric, as more resources are allocated for transmissions in the downlink direction (e.g., transmissions from the scheduling entity) than for transmissions in the uplink direction (e.g., transmissions from the subordinate entities).

In one example, the control information portion <NUM> may be used to transmit a physical downlink control channel (PDCCH) indicating time-frequency assignments of data packets intended for one or more subordinate entities in the current subframe <NUM> and/or subsequent subframe(s), and the DL data portion <NUM> may be used to transmit a data payload including the data packets intended for the one or more subordinate entities within the assigned time-frequency slots of the current subframe <NUM> and/or subsequent subframe(s). Thus, each subordinate entity that will be receiving data in the data portion <NUM> of the subframe <NUM> may be individually addressed in the control portion <NUM> of the current subframe <NUM> and/or previous subframe(s), so that the subordinate entities can receive and process the correct downlink data packets. Following the GP portion <NUM>, the scheduling entity may receive an ACK signal (or a NACK signal) during the ACK/NACK portion <NUM> from each subordinate entity that received data packets during the data portion <NUM> of the current subframe and/or previous subframe(s) to indicate whether the data packets were successfully received.

In other examples, the control portion <NUM> may be used to transmit other downlink control channels and/or other downlink pilots, such as the channel state information - reference signal (CSI-RS). These additional downlink channels and/or pilots, along with any other downlink control information, may be transmitted together with the PDCCH within the control portion <NUM>. Broadly, any suitable transmission in the DL direction may be made complementary to the control information described above within the control portion <NUM>. In addition, the ACK/NACK portion <NUM> may also be used for transmission of other uplink control channels and information, such as the physical uplink control channel (PUCCH), random access channel (RACH), scheduling request (SR), sounding reference signal (SRS), channel quality indicator (CQI), channel state feedback information and buffer status. Broadly, any suitable transmission in the UL direction may be made complementary to the ACK/NACK and other information described above within the ACK/NACK portion <NUM>.

In an aspect of the disclosure, the data portion <NUM> may be used to multiplex DL data transmissions to a set of subordinate entities (i.e., two or more subordinate entities) within the subframe <NUM>. For example, the scheduling entity may multiplex downlink data to the set of subordinate entities using time division multiplexing (TDM), frequency division multiplexing (FDM) (i.e., OFDM), code division multiplexing (CDM), and/or any suitable multiplexing scheme known to those of ordinary skill in the art. Thus, the DL data portion <NUM> may include data for multiple users and up to a high order of multi-user MIMO. In addition, the control portion <NUM> and ACK/NACK portion <NUM> may also be used to multiplex control information to or from a set of subordinate entities in a TDM, FDM, CDM, and/or other suitable manner.

The GP portion <NUM> may be scheduled to accommodate variability in UL and DL timing. For example, latencies due to RF antenna direction switching (e.g., from DL to UL) and RF settling (e.g., settling of phase lock loops, filters and power amplifiers), along with transmission path latencies, may cause the subordinate entity to transmit early on the UL to match DL timing. Such early transmission may interfere with symbols received from the scheduling entity. Accordingly, the GP portion <NUM> may allow an amount of time after the DL data portion <NUM> to prevent interference, where the GP portion <NUM> may provide an appropriate amount of time for the scheduling entity to switch its RF antenna direction, for the over-the-air (OTA) transmission time, and time for ACK processing by the subordinate entity. The GP portion <NUM> may further provide an appropriate amount of time for the subordinate entity to switch its RF antenna direction (e.g., from DL to UL), to processes the data payload, and for the over-the-air (OTA) transmission time.

The duration of the GP portion <NUM> may be configurable based on, for example, the cell size and/or processing time requirements. For example, the GP portion <NUM> may have a duration of one symbol period (e.g., <NUM>). However, in accordance with aspects of the disclosure, the switch point from DL to UL transmissions may be deterministic throughout the network. Thus, although the beginning point of the GP portion <NUM> may be variable and configurable, the ending point of the GP portion <NUM> corresponding to the switch point from DL transmissions to UL transmissions may be fixed by the network to manage interference between DL and UL transmissions. In an aspect of the disclosure, the switch point may be updated by the network in a semi-static manner and indicated in the PDCCH. In addition, the GP duration and/or beginning point of the GP portion <NUM> may also be indicated in the PDCCH.

In the example of the UL-centric subframe <NUM> shown in <FIG>, the DL transmission portions include a control portion <NUM> and an acknowledgement portion <NUM>, and the UL transmission portions include a data portion <NUM>. Therefore, within the UL-centric subframe structure shown in <FIG>, the subordinate entity first has an opportunity to receive control information in the control portion <NUM>. Following a GP portion <NUM>, the subordinate entity has an opportunity to transmit data in the UL data portion <NUM>, and following another GP portion <NUM>, to receive acknowledgement information (e.g., an ACK/NACK signal) in the ACK/NACK portion <NUM>. This frame structure is uplink-centric, as more resources are allocated for transmissions in the uplink direction (e.g., transmissions from the subordinate entity) than in the downlink direction (e.g., transmissions from the scheduling entity).

In one example, the control information portion <NUM> may be used to transmit a physical downlink control channel (PDCCH) indicating time-frequency assignments of data packets to be transmitted by one or more subordinate entities in the current subframe <NUM> and/or subsequent subframe(s), and the data portion <NUM> may be used to by the subordinate entities to transmit their data packets to the scheduling entity within the assigned time-frequency slots in the current subframe <NUM> and/or subsequent subframe(s). Each subordinate entity that transmitted data within the data portion <NUM> may then receive an ACK signal (or a NACK signal) during the ACK/NACK portion <NUM> of the current subframe <NUM> and/or subsequent subframe(s) from the scheduling entity to indicate whether the data packets were successfully received at the scheduling entity.

In other examples, the control portion <NUM> and/or ACK/NACK portion <NUM> may be used to transmit other downlink control channels and information and/or data from other layers. In addition, the data portion <NUM> may also be used to transmit uplink control channels and information. For example, the control portion <NUM> of a subframe <NUM> may carry a data transmission (e.g., a small payload of data) for a subordinate entity, such as an application layer (or layer other than the physical layer) ACK from a previous subframe. The subordinate entity may then acknowledge the data transmission in the data portion <NUM> of the same subframe <NUM> and/or subsequent subframe(s).

In an aspect of the disclosure, the UL data portion <NUM> may be used to carry data transmissions from a set of subordinate entities (i.e., two or more subordinate entities) within the subframe <NUM> using one or more of TDMA, FDMA, CDMA, or any other suitable multiple access scheme. Thus, the UL data portion <NUM> may include packets from multiple users and up to a high order of multi-user MIMO. In addition, the control portion <NUM> and ACK/NACK portion <NUM> may also be used to carry control information to a set of subordinate entities in a TDMA, FDMA, CDMA, or other suitable multiple access manner. In an aspect of the disclosure, UL data processing at the scheduling entity may be amortized over the entire TTI. For example, the control portion <NUM>, the ACK/NACK portion <NUM>, and part of the GP portion <NUM> may all be used to decode UL data in the data portion <NUM>.

<FIG> is a diagram illustrating a DL-centric TDD subframe structure <NUM> implementing a single interlace mode. In the single interlace mode, downlink (DL)-centric subframes <NUM> and <NUM> are each self-contained, such that control information, data information corresponding to the control information and ACK information corresponding to the data information are all included within a single DL-centric subframe <NUM> or <NUM>. For example, control information may be transmitted by the scheduling entity in a control information portion <NUM> of a first DL-centric subframe <NUM>, data information corresponding to the control information (as indicated by the arrow pointing from the control portion <NUM> to a data portion <NUM>) may be transmitted by the scheduling entity in the data portion <NUM> of the first DL-centric subframe <NUM> and acknowledgement information corresponding to the data information (as indicated by the arrow pointing from the data portion <NUM> to an ACK/NACK portion <NUM>) may be received by the scheduling entity from subordinate entities in the ACK/NACK portion <NUM> of the first DL-centric subframe <NUM>.

Based on the ACK/NACK information received in the ACK/NACK portion <NUM> of the first DL-centric subframe <NUM>, the scheduling entity generates control information for a control portion <NUM> of a next (second) DL-centric subframe <NUM> (as indicated by the arrow pointing from the ACK/NACK portion <NUM> to the control portion <NUM>). For example, if the ACK/NACK information includes a NACK signal, at least part of the coded bits of the data information transmitted in the data portion <NUM> of the first DL-centric subframe <NUM> may be retransmitted in a data portion <NUM> of the second DL-centric subframe <NUM>.

<FIG> is a diagram illustrating a DL-centric TDD subframe structure <NUM> implementing a multiple interlace mode that provides additional processing time in the scheduling entity by delaying HARQ retransmission one or more subframes. In <FIG>, each DL-centric TDD subframe <NUM>, <NUM>, and <NUM> may be self-contained. However, retransmissions are not scheduled in back-to-back subframes. Instead, retransmissions may be scheduled in subsequent subframes (e.g., every other subframe or any other delayed scheduling configuration).

For example, the first DL-centric subframe <NUM> may be self-contained such that control information in a control information portion <NUM>, data information corresponding to the control information (as indicated by the arrow pointing from the control portion <NUM> to a data portion <NUM>) and acknowledgement information corresponding to the data information (as indicated by the arrow pointing from the data portion <NUM> to an ACK/NACK portion <NUM>) may be included in the first DL-centric subframe <NUM>. However, to allow for additional ACK/NACK processing time in the scheduling entity, instead of scheduling HARQ retransmissions in the next DL-centric subframe <NUM>, the scheduling entity can delay retransmission until DL-centric subframe <NUM> for one or more subordinate entities. For example, based on the ACK/NACK information received from one or more subordinate entities in the ACK/NACK portion <NUM> of the first DL-centric subframe <NUM>, the scheduling entity may schedule the next transmission for those one or more subordinate entities in DL-centric subframe <NUM> (as indicated by the arrow pointing from the ACK/NACK portion <NUM> to the control portion <NUM> of DL-centric subframe <NUM>).

In an aspect of the disclosure, the scheduling entity may multiplex both single interlace subordinate entities and multiple interlace subordinate entities within TDD subframes <NUM>, <NUM>, and <NUM>. For example, the scheduling entity may schedule high throughput subordinate entities in the single interlace mode and low throughput subordinate entities in the multiple interlace mode. The high throughput subordinate entities may be scheduled, for example, in DL-centric frames <NUM>, <NUM>, and <NUM>, while low throughput subordinate entities may be scheduled in DL-centric frames <NUM> and <NUM>. In an additional aspect, for one or more of the single interlace subordinate entities, the scheduling entity may utilize pre-generated waveforms for HARQ retransmission and/or new transmissions to ensure the scheduling entity meets the scheduling timeline requirements for the single interlace mode subordinate entities.

<FIG> is a diagram illustrating a TDD subframe structure <NUM> implementing a multiple interlace mode that provides additional processing time in the subordinate entity by delaying ACK/NACK information one or more subframes. In <FIG>, although the DL-centric TDD subframe structure remains the same, each DL-centric subframe <NUM>, <NUM>, and <NUM> may not be self-contained. Instead, the ACK/NACK portion in a particular subframe may correspond to data transmitted in a previous subframe.

For example, in the first DL-centric subframe <NUM>, data information in a data portion <NUM> corresponds to control information in a control portion <NUM> (as indicated by the arrow pointing from the control portion <NUM> to a data portion <NUM>). However, to allow for additional data processing time in one or more subordinate entities, instead of scheduling ACK/NACK signals for those one or more subordinate entities in the first DL-centric subframe <NUM>, the scheduling entity can schedule ACK/NACK signals in the next DL-centric subframe <NUM> or in any other subsequent DL-centric subframe. In the example shown in <FIG>, the ACK/NACK signals from those one or more subordinate entities can be received by the scheduling entity in the acknowledgement portion <NUM> of the second DL-centric subframe <NUM>. Then, based on the ACK/NACK information received in the ACK/NACK portion <NUM> of the second DL-centric subframe <NUM>, the scheduling entity may schedule the next transmission for those one or more subordinate entities in DL-centric subframe <NUM> (as indicated by the arrow pointing from the ACK/NACK portion <NUM> to the control portion <NUM> of DL-centric subframe <NUM>) or in any other subsequent DL-centric subframe.

In an aspect of the disclosure, the scheduling entity may multiplex both single interlace subordinate entities and multiple interlace subordinate entities within TDD subframes <NUM>, <NUM>, and <NUM>. For example, the scheduling entity may schedule high throughput subordinate entities in the single interlace mode and low throughput subordinate entities in the multiple interlace mode. The high throughput subordinate entities may be scheduled to transmit ACK/NACK in TDD subframes <NUM>, <NUM>, and <NUM>, while low throughput subordinate entities may be scheduled to transmit ACK/NACK in TDD subframe <NUM>. In an additional aspect, the scheduling entity may multiplex single interlace, ACK-delayed multiple interlace and control-delayed multiple interlace subordinate entities within TDD subframes <NUM>, <NUM>, and <NUM>. The scheduling entity may further delay both the control and ACK for one or more subordinate entities and multiplex such control/ACK-delayed multiple interlace subordinate entities with single interlace subordinate entities and other types of multiple interlace subordinate entities (ACK-delayed and/or control-delayed).

<FIG> is a diagram illustrating a DL-centric TDD subframe structure <NUM> implementing a multiple interlace mode in which the control information is prescheduled. In <FIG>, although the DL-centric TDD subframe structure remains the same, each DL-centric subframe <NUM> and <NUM> may not be self-contained. Instead, the control portion of a particular subframe may correspond to data transmitted in a subsequent subframe.

For example, control information in a control portion <NUM> of a first DL-centric subframe <NUM> may correspond to data information in a data portion <NUM> of a second DL-centric subframe <NUM> (as indicated by the arrow pointing from the control portion <NUM> to the data portion <NUM>). The acknowledgement information corresponding to the data information may be included in the acknowledgement portion <NUM> of the second DL-centric subframe <NUM> (as indicated by the arrow pointing from the data portion <NUM> to the acknowledgement portion <NUM>) or may be included in a subsequent subframe to extend the processing time of the subordinate entity. In addition, although not shown, retransmissions and/or new transmissions may be scheduled in a next DL-centric subframe after the second DL-centric subframe <NUM> or in any subsequent DL-centric subframe to extend the processing time of the scheduling entity.

In an aspect of the disclosure, prescheduling the control information may support efficient micro-sleep and dynamic bandwidth switching by providing a delay between the control information and the data information. This delay enables the subordinate entity to wake up and open a larger bandwidth receiver before receipt of the data. The subordinate entity may monitor the control channel and enter into a micro-sleep state when no control grant is detected.

<FIG> is a diagram illustrating a DL-centric TDD subframe structure <NUM> implementing a control-prescheduled multiple interlace mode that supports an enhanced physical downlink control channel (ePDCCH) <NUM>. With an ePDCCH, control information may be spread out, e.g., over the entire subframe to boost the downlink control channel link budget. For example, control information corresponding to an ePDCCH <NUM> may overlap, in time, both a control portion <NUM> and a data portion <NUM> of a first DL-centric subframe <NUM>. In one example, as illustrated in <FIG>, the control information in the ePDCCH <NUM> may be multiplexed with the control and data portions <NUM> and <NUM>, respectively, using Frequency Division Multiplexing (FDM) relative to the control and data portions. In other examples, the control information in the ePDCCH <NUM> may be multiplexed with the control and data portions <NUM> and <NUM> by a scrambling code using Code Division Multiplexing (CDM); or the control information in the ePDCCH <NUM> may be multiplexed with the control and data portions <NUM> and <NUM>, respectively, using Time Division Multiplexing (TDM).

Data information corresponding to the control information may then be included in a data portion <NUM> of a next (second) DL-centric subframe <NUM> (as indicated by the arrow pointing from the control portions <NUM>/<NUM> to the data portion <NUM>). The acknowledgement information corresponding to the data information may be included in the acknowledgement portion <NUM> of the second DL-centric subframe <NUM> (as indicated by the arrow pointing from the data portion <NUM> to the acknowledgement portion <NUM>) or may be included in a subsequent subframe to extend the processing time of the subordinate entity. In addition, although not shown, retransmissions and/or new transmissions may be scheduled in a next DL-centric subframe after the second DL-centric subframe <NUM> or in any subsequent DL-centric subframe to extend the processing time of the scheduling entity.

In an aspect of the disclosure, the scheduling entity may multiplex control-prescheduled multiple interlace subordinate entities with single interlace subordinate entities and other types of multiple interlace subordinate entities within the same TDD subframe structure. For example, the scheduling entity may schedule high throughput subordinate entities in the single interlace mode and low throughput subordinate entities in the control-prescheduled and/or control/ACK-delayed multiple interlace mode.

<FIG> is a diagram illustrating an UL-centric TDD subframe structure <NUM> implementing a multiple interlaced mode in which the UL ACK is channelized in an UL-centric subframe <NUM>. For example, the ACKs from one or more DL-centric subframes <NUM>, <NUM>, and <NUM> may be grouped together and transmitted within a data portion <NUM> of an UL-centric subframe <NUM>. In an aspect of the disclosure, channelizing the ACKs in some of the UL-centric subframes <NUM> may boost the ACK link budget by enabling an increase in the duration and/or number of ACK symbols. In other aspects, the ACKs may be bundled over multiple DL-centric/UL-centric subframes. For example, systematic ACKs may be sent in each DL-centric subframe, and parity ACKs (e.g., redundancy versions of the systematic ACKs) may be sent in some DL-centric subframes and/or UL-centric subframes to further improve the efficiency of the ACKs. Coding may also be used across these ACKs to improve the reliability of the ACKs.

Similarly, DL ACKs from one or more UL-centric subframes may be grouped together and transmitted within the control, data, and/or ACK portion of a DL-centric subframe. For example, the DL ACK from UL-centric subframe <NUM> may be transmitted within the control, data, and/or ACK portion of DL-centric subframe <NUM>.

In addition to acknowledgement information, data and/or scheduling information may also be transmitted between UL-centric and DL-centric subframes. In one example, a DL data retransmission corresponding to a NACK in the ACK portion of a DL-centric subframe may be included within an UL-centric subframe. Similarly, an UL data retransmission corresponding to a NACK in the ACK portion of an UL-centric subframe may be included within a DL-centric subframe. In another example, scheduling information for data to be transmitted within a DL-centric subframe may be included within a prior UL-centric subframe (and vice-versa).

<FIG> is a diagram illustrating an UL-centric TDD subframe structure <NUM> implementing a multiple interlace mode that provides additional processing time in the scheduling entity by delaying DL ACK/NACK one or more subframes. In <FIG>, although the UL-centric TDD subframe structure remains the same, each UL-centric TDD subframe <NUM> and <NUM> may not be self-contained. Instead, the DL ACK/NACK portion in a particular UL-centric subframe may correspond to data transmitted in a previous UL-centric subframe.

For example, in the first UL-centric subframe <NUM>, data information transmitted by subordinate entities in a data portion <NUM> corresponds to control information transmitted by the scheduling entity in a control portion <NUM> (as indicated by the arrow pointing from the control portion <NUM> to a data portion <NUM>). However, to allow for additional data processing time by the scheduling entity, instead of scheduling DL ACK/NACK signals transmitted by the scheduling entity in the first subframe <NUM>, the scheduling entity can schedule ACK/NACK signals in the next UL-centric subframe <NUM>. Thus, the ACK/NACK signals can be sent to the subordinate entities in the acknowledgement portion <NUM> of the second UL-centric subframe <NUM> (as indicated by the arrow pointing from the data portion <NUM> to the acknowledgement portion <NUM>).

<FIG> is a diagram illustrating an UL-centric TDD subframe structure <NUM> implementing a multiple interlace mode that provides additional processing time in the subordinate entities and relaxed scheduling in the scheduling entity by delaying UL retransmissions one or more subframes. In <FIG>, although the UL-centric TDD subframe structure remains the same, each UL-centric TDD subframe <NUM>, <NUM>, and <NUM> may not be self-contained. Instead, UL retransmissions may be scheduled in subsequent UL-centric subframes (e.g., every other UL-centric subframe or any other delayed scheduling configuration).

For example, in the first UL-centric subframe <NUM>, data information transmitted by subordinate entities in a data portion <NUM> corresponds to control information transmitted by the scheduling entity in a control portion <NUM> (as indicated by the arrow pointing from the control portion <NUM> to a data portion <NUM>). In addition, acknowledgement information transmitted by the scheduling entity and corresponding to the data information may be included in the acknowledgement (ACK/NACK) portion <NUM> of the first UL-centric subframe <NUM> (as indicated by the arrow pointing from the data portion <NUM> to the ACK/NACK portion <NUM>). However, to allow for additional ACK/NACK processing time in the subordinate entities, instead of scheduling HARQ retransmissions in the next TDD subframe <NUM>, the scheduling entity can delay retransmission until UL-centric TDD subframe <NUM> for one or more subordinate entities (as indicated by the arrow pointing from the ACK/NACK portion <NUM> to the control portion <NUM> of UL-centric subframe <NUM>).

In an aspect of the disclosure, the scheduling entity may multiplex both single interlace subordinate entities and multiple interlace subordinate entities within UL-centric TDD subframes. For example, the scheduling entity may schedule high throughput subordinate entities in the single interlace mode and low throughput subordinate entities in the multiple interlace mode. The high throughput subordinate entities may be scheduled to transmit data in UL-centric subframes <NUM>, <NUM>, and <NUM>, while low throughput subordinate entities may be scheduled to transmit data in UL-centric subframes 1301and <NUM>. In an additional aspect, the scheduling entity may multiplex single interlace, ACK-delayed multiple interlace and control-delayed multiple interlace subordinate entities within UL-centric subframes <NUM>, <NUM>, and <NUM>. The scheduling entity may further delay both the DL control and DL ACK for one or more subordinate entities and multiplex such control/ACK-delayed multiple interlace subordinate entities with single interlace subordinate entities and other types of multiple interlace subordinate entities (ACK-delayed and/or control-delayed).

<FIG> is a diagram illustrating an UL-centric TDD subframe structure <NUM> implementing a multiple interlace mode in which the control information is prescheduled to relax the control/data processing timeline in the subordinate entities. In <FIG>, although the UL-centric TDD subframe structure remains the same, each UL-centric TDD subframe <NUM> and <NUM> may not be self-contained. Instead, the control portion of a particular UL-centric subframe may correspond to data transmitted by one or more subordinate entities in a subsequent UL-centric subframe.

For example, control information transmitted by a scheduling entity in a control portion <NUM> of a first UL-centric subframe <NUM> may correspond to data information transmitted by one or more subordinate entities in a data portion <NUM> of a second UL-centric subframe <NUM> (as indicated by the arrow pointing from the control portion <NUM> to the data portion <NUM>). The acknowledgement information transmitted by the scheduling entity and corresponding to the data information may be included in the acknowledgement portion <NUM> of the second DL-centric subframe <NUM> or may be included in a subsequent UL-centric subframe to extend the processing time of the scheduling entity. In addition, although not shown, retransmissions and/or new transmissions by subordinate entities may be scheduled in a next UL-centric subframe after the second DL-centric subframe <NUM> or in a subsequent UL-centric subframe to extend the processing time of the scheduling entity.

<FIG> is a flow chart <NUM> of a method of wireless communication utilizing a TDD subframe structure. The method may be performed by a scheduling entity as described above and illustrated in <FIG> and <FIG>, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block <NUM>, the scheduling entity provides a single interlace mode of operation. For example, with reference to <FIG> and <FIG>, the single interlace mode of operation may include a self-contained UL-centric and/or DL-centric TDD subframe structure in which the control information, data information corresponding to the control information, and acknowledgement information corresponding to the data information are transmitted within a single TDD subframe.

At block <NUM>, the scheduling entity provides a multiple interlace mode of operation. In various aspects, with reference to <FIG>, the multiple interlace mode of operation may include the same basic UL-centric and/or DL-centric TDD subframe structure as the single interlace mode, but with one or more of the control, data, or acknowledgement information transmitted in a separate UL-centric or DL-centric TDD subframe.

At block <NUM>, the scheduling entity determines a respective scheduling mode for each subordinate entity from the single interlace and multiple interlace modes. In an aspect of the disclosure, the scheduling entity considers one or more factors when assigning a particular scheduling mode to a subordinate entity. Examples of factors may include, but are not limited to, throughput requirements, HARQ buffer requirements, latency requirements, processing speed of both the subordinate and scheduling entities, power consumption requirements of both the subordinate and scheduling entities, whether the subordinate entity has entered a micro-sleep mode, and the link budget of the uplink and downlink. The scheduling mode may be statically determined or dynamically updated periodically, based upon scheduling requirements of the scheduling entity, or upon request from the subordinate entity.

At block <NUM>, the scheduling entity schedules transmissions to the subordinate entities by multiplexing the scheduling modes assigned to the subordinate entities within a TDD subframe structure. For example, single interlace subordinate entities may be scheduled to transmit ACK/NACK signals in each DL-centric TDD subframe or data in each UL-centric TDD subframe, while each interlace of multiple interlace subordinate entities may be scheduled to transmit ACK/NACK signals in alternating DL-centric TDD subframes or data in alternating UL-centric subframes (with multiple interlaces alternating between adjacent subframes).

<FIG> is a flow chart <NUM> of a method of wireless communication utilizing a TDD subframe structure in a single interlace mode of operation. The method may be performed by a scheduling entity as described above and illustrated in <FIG> and <FIG>, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block <NUM>, the scheduling entity determines the scheduling mode for a subordinate entity is a single interlace mode of operation. In the single interlace mode of operation, a self-contained TDD subframe structure is utilized to generate a self-contained subframe. For example, with reference to <FIG> and <FIG>, the self-contained subframe structure may be a DL-centric subframe or an UL-centric subframe, in which the control information, data information corresponding to the control information and acknowledgement information corresponded to the data information are included within a single TDD subframe.

At block <NUM>, the scheduling entity generates a subframe having the self-contained subframe structure and includes control information in the control portion of the subframe. For a DL-centric subframe, the control information may include a PDCCH indicating the time-frequency resource assignments for data transmissions from the scheduling entity to the subordinate entity. For an UL-centric subframe, the control information may include a PDCCH indicating the time-frequency resource assignments for data transmissions from the subordinate entity to the scheduling entity. In addition, other downlink control information may also be included within the control portion.

At block <NUM>, data information corresponding to the control information is included in the data portion of the subframe. For example, in a DL-centric subframe, the data information may include data packets transmitted to the subordinate entity on a downlink data channel. In an UL-centric subframe, the data information may include data packets transmitted from the subordinate entity on an uplink data channel.

At block <NUM>, acknowledgement information corresponding to the data information is included in the acknowledgement portion of the subframe. For example, in a DL-centric subframe, an ACK/NACK message from the subordinate entity that received data in the data portion of the subframe may be included in the acknowledgement portion of the subframe to indicate whether the subordinate entity correctly received the downlink data. In an UL-centric subframe, the acknowledgement information may include an ACK/NACK message to the subordinate entity that transmitted data in the data portion of the subframe to indicate whether the scheduling entity correctly received the uplink data.

<FIG> is a flow chart <NUM> of a method of wireless communication utilizing a TDD subframe structure in a multiple interlace mode of operation. The method may be performed by a scheduling entity as described above and illustrated in <FIG> and <FIG>, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block <NUM>, the scheduling entity determines the scheduling mode for a subordinate entity is a multiple interlace mode of operation. In the multiple interlace mode of operation, two or more TDD subframes are utilized to transmit the control, data (or retransmitted data) and acknowledgement information. Although the subframe structure in the multiple interlace mode of operation may be the same as that in the single interlace mode of operation, the subframe structure may not be entirely self-contained.

At block <NUM>, the scheduling entity generates a first subframe and includes control information in the control portion of the first subframe. For a DL-centric subframe, the control information may include a PDCCH indicating the time-frequency resource assignments for data transmissions from the scheduling entity to the subordinate entity. For an UL-centric subframe, the control information may include a PDCCH indicating the time-frequency resource assignments for data transmissions from the subordinate entity to the scheduling entity. In addition, other downlink control information may also be included within the control portion.

At block <NUM>, data information corresponding to the control information is included in the data portion of the first subframe. For example, in a DL-centric subframe, the data information may include data packets transmitted to the subordinate entity on a downlink data channel. In an UL-centric subframe, the data information may include data packets transmitted from the subordinate entity on an uplink data channel.

At block <NUM>, when a NACK is included in the acknowledgement information, the scheduling entity generates a second subframe subsequent to the first subframe and retransmits the data from the first subframe in a data portion of the second subframe. As shown in <FIG> and <FIG>, the second subframe may be separated in time from the first subframe by at least one intermediate subframe.

At block <NUM>, the scheduling entity generates a second subframe subsequent to the first subframe and includes acknowledgement information corresponding to the data information in the acknowledgement portion of the second subframe. For example, in a DL-centric subframe as shown in <FIG>, an ACK/NACK message from the subordinate entity that received data in the data portion of the first subframe may be included in the acknowledgement portion of the second subframe to indicate whether the subordinate entity correctly received the downlink data. In an UL-centric subframe as shown in <FIG>, the acknowledgement information may include an ACK/NACK message to the subordinate entity that transmitted data in the data portion of the first subframe to indicate whether the scheduling entity correctly received the uplink data.

At block <NUM>, the scheduling entity generates a second subframe subsequent to the first subframe and includes data information corresponding to the control information in the data portion of the second subframe. For example, in a DL-centric subframe as shown in <FIG> and <FIG>, the data information may include data packets transmitted to the subordinate entity on a downlink data channel. In an UL-centric subframe as shown in <FIG>, the data information may include data packets transmitted from the subordinate entity on an uplink data channel.

At block <NUM>, acknowledgement information corresponding to the data information is included in the acknowledgement portion of the second subframe. For example, in a DL-centric subframe as shown in <FIG>, an ACK/NACK message from the subordinate entity that received data in the data portion of the second subframe may be included in the acknowledgement portion of the second subframe to indicate whether the subordinate entity correctly received the downlink data. In an UL-centric subframe as shown in <FIG>, the acknowledgement information may include an ACK/NACK message to the subordinate entity that transmitted data in the data portion of the first subframe to indicate whether the scheduling entity correctly received the uplink data.

At block <NUM>, the scheduling entity generates a DL-centric subframe and includes control information in the control portion of the DL-centric subframe. For example, the control information may include a PDCCH indicating the time-frequency resource assignments for data transmissions from the scheduling entity to the subordinate entity.

At block <NUM>, data information corresponding to the control information is included in the data portion of the DL-centric subframe. For example, the data information may include data packets transmitted to the subordinate entity on a downlink data channel.

At block <NUM>, the scheduling entity generates an UL-centric subsequent to the DL-centric subframe and includes acknowledgement information corresponding to the data information in the UL-centric subframe. For example, as shown in <FIG>, an ACK/NACK message from the subordinate entity that received data in the data portion of the DL-centric subframe may be included in the data portion of the UL-centric subframe to indicate whether the subordinate entity correctly received the downlink data.

As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to any suitable telecommunication system, network architecture, and communication standard. By way of example, various aspects may be applied to UMTS systems such as W-CDMA, TD-SCDMA, and TD-CDMA. Various aspects may also be applied to systems employing Long Term Evolution (LTE) (in FDD, TDD, or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems, including those described by yet-to-be defined wide area network standards.

For instance, a first die may be coupled to a second die in a package even though the first die is never directly physically in contact with the second die.

Claim 1:
A method of wireless communication in a wireless communication network performed by a scheduling entity to communicate with a set of one or more subordinate entities utilizing a time division duplex, TDD, carrier, wherein the TDD carrier comprises a plurality of subframes, each having a TDD subframe structure, the method comprising:
providing (<NUM>) a single interlace mode of operation in which control information, data information and acknowledgement information corresponding to the data information are included in a single subframe;
providing (<NUM>) a multiple interlace mode of operation in which at least one of the control information, the data information or the acknowledgement information corresponding to the data information is included in a different subframe than other ones of the control information, the data information and the acknowledgement information corresponding to the data information;
determining (<NUM>) a respective scheduling mode for each subordinate entity in the set of one or more subordinate entities for a first subframe, the respective scheduling mode including the single interlace mode of operation or the multiple interlace mode of operation; and
scheduling (<NUM>) transmissions between the scheduling entity and the set of one or more subordinate entities by multiplexing the respective scheduling mode of each subordinate entity of the set of subordinate entities to include both the single interface mode of operation and the multiple interlace mode of operation within the TDD subframe structure of the first subframe.