Bundling and hybrid automatic repeat request operation for enhanced machine-type communication

Methods, systems, and devices for wireless communication are described. A user equipment (UE), which may be a machine-type communication device and may have a half-duplex capability, may receive grants for uplink resources and downlink resources that overlap in time. The UE may prioritize the grants and either drop the low priority grant or may monitor a non-overlapping portion of resources assigned by the lower priority grant, for example. The UE may determine an acknowledgement mode for the downlink transmission based on one or more grants or on an explicit indication from a base station in some examples. A control format indicator may be interpreted based on the grant or on the bundling size. In some cases, the UE may identify a retuning time (e.g., for switching between transmit and receive modes or for switching frequencies) and may determine uplink and downlink bundling sizes based on the retuning time.

BACKGROUND

The following relates generally to wireless communication, and more specifically to bundling and hybrid automatic repeat request (HARQ) operation for enhanced machine-type communication (MTC).

A UE may support communication in one direction at a time (e.g., half duplexing) and may be unable to simultaneously transmit and receive. For example, machine-type communications (MTC) devices may support either uplink transmissions or downlink monitoring in a subframe. Furthermore, control information may be communicated using one or more uplink or downlink grants. If a device receives an uplink grant and a downlink grant simultaneously, the device may not be able to transmit and receive using the assigned resources.

SUMMARY

A user equipment (UE), which may be a machine-type communication (MTC) device with a half-duplexing capability, may receive grants for overlapping uplink and downlink resources. The UE may prioritize the grants and, for example, drop the low priority grant or monitor the non-overlapping portion resources assigned by the low priority grant. The UE may determine an acknowledgement mode for downlink transmissions based on one or more grants or on an explicit indication from a base station. A control format indicator may, in some cases, be interpreted based on the grant or on a bundling size of a downlink or uplink channel. In some cases the UE may also identify a retuning time (e.g., for switching between transmit and receive modes or for switching frequencies) and may determine uplink and downlink bundling sizes based on the retuning time.

A method of wireless communication is described. The method may include receiving a first grant for a first set of resources, receiving a second grant for a second set of resources, determining that a portion of the first set of resources overlaps with a portion of the second set of resources, and communicating using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant.

An apparatus for wireless communication is described. The apparatus may include means for receiving a first grant for a first set of resources, means for receiving a second grant for a second set of resources, means for determining that a portion of the first set of resources overlaps with a portion of the second set of resources, and means for communicating using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to receive a first grant for a first set of resources, receive a second grant for a second set of resources, determine that a portion of the first set of resources overlaps with a portion of the second set of resources, and communicate using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to receive a first grant for a first set of resources, receive a second grant for a second set of resources, determine that a portion of the first set of resources overlaps with a portion of the second set of resources, and communicate using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for dropping the first grant or the second grant based at least in part on the prioritization. Additionally or alternatively, in some examples communicating using the first set of resources or the second set of resources comprises communicating using the first set of resources and a non-overlapped portion of the second set of resources.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the first and second sets of resources each comprise bundled resources of an uplink channel or a downlink channel.

A method of wireless communication is described. The method may include identifying a retuning time for a UE to switch between a transmitting mode and a receiving mode based at least in part on a half-duplex communication capability of the UE, determining a first bundling size for an uplink data channel and a second bundling size for a downlink control channel based at least in part on the retuning time, and communicating according to the retuning time and the first bundling size or the second bundling size.

An apparatus for wireless communication is described. The apparatus may include means for identifying a retuning time for a UE to switch between a transmitting mode and a receiving mode based at least in part on a half-duplex communication capability of the UE, means for determining a first bundling size for an uplink data channel and a second bundling size for a downlink control channel based at least in part on the retuning time, and means for communicating according to the retuning time and the first bundling size or the second bundling size.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to identify a retuning time for a UE to switch between a transmitting mode and a receiving mode based at least in part on a half-duplex communication capability of the UE, determine a first bundling size for an uplink data channel and a second bundling size for a downlink control channel based at least in part on the retuning time, and communicate according to the retuning time and the first bundling size or the second bundling size.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to identify a retuning time for a UE to switch between a transmitting mode and a receiving mode based at least in part on a half-duplex communication capability of the UE, determine a first bundling size for an uplink data channel and a second bundling size for a downlink control channel based at least in part on the retuning time, and communicate according to the retuning time and the first bundling size or the second bundling size.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for determining for a frequency division duplexing (FDD) configuration that the downlink control channel overlaps with the retuning time, wherein the communicating comprises refraining from decoding the downlink control channel. Additionally or alternatively, in some examples determining the first bundling size comprises reducing the first bundling size or the second bundling size from a nominal bundling size based at least in part on a the retuning time.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for determining for a time division duplexing (TDD) whether the uplink data channel and the downlink control channel comprise frequency resources of a same narrowband region. Additionally or alternatively, in some examples the communicating comprises decoding the downlink control channel when the uplink data channel and the downlink control channel comprise frequency resources of the same narrowband region.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the first bundling size or the second bundling size is based at least in part on whether the uplink data channel and the downlink control channel comprise frequency resources of the same narrowband region. Additionally or alternatively, in some examples a starting time for the downlink control channel is based at least in part on the retuning time and the first bundling size.

A method of wireless communication is described. The method may include receiving a grant for a downlink transmission, and determining an acknowledgement mode for the downlink transmission based at least in part on the grant.

An apparatus for wireless communication is described. The apparatus may include means for receiving a grant for a downlink transmission, and means for determining an acknowledgement mode for the downlink transmission based at least in part on the grant.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to receive a grant for a downlink transmission, and determine an acknowledgement mode for the downlink transmission based at least in part on the grant.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to receive a grant for a downlink transmission, and determine an acknowledgement mode for the downlink transmission based at least in part on the grant.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission and an indication of a bundling configuration for the acknowledgment message. Additionally or alternatively, in some examples the grant comprises an indication that the acknowledgment message mode uses acknowledgement messages for the downlink transmission, and wherein a bundling configuration for the acknowledgment message is based at least in part on a bundling configuration for the grant.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission and an indication of resources for the acknowledgement message. Additionally or alternatively, in some examples the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission, and wherein resources for the acknowledgement message determined based at least in part on the grant and a bundling size.

A method of wireless communication is described. The method may include determining an acknowledgement message mode for a downlink transmission based at least in part on a channel condition, and transmitting a grant to assign resources for the downlink transmission, wherein the grant comprises an indication of the acknowledgement message mode.

An apparatus for wireless communication is described. The apparatus may include means for determining an acknowledgement message mode for a downlink transmission based at least in part on a channel condition, and means for transmitting a grant to assign resources for the downlink transmission, wherein the grant comprises an indication of the acknowledgement message mode.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to determine an acknowledgement message mode for a downlink transmission based at least in part on a channel condition, and transmit a grant to assign resources for the downlink transmission, wherein the grant comprises an indication of the acknowledgement message mode.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to determine an acknowledgement message mode for a downlink transmission based at least in part on a channel condition, and transmit a grant to assign resources for the downlink transmission, wherein the grant comprises an indication of the acknowledgement message mode.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission and a bundling configuration for the acknowledgment message. Additionally or alternatively, in some examples the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission, and wherein a bundling configuration for the acknowledgment message is based at least in part on a bundling configuration for the grant.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission and an indication of resources for the acknowledgement message. Additionally or alternatively, in some examples the grant comprises an indication that the acknowledgment mode uses acknowledgement messages for the downlink transmission, and wherein resources for the acknowledgement message are based at least in part on the grant and a bundling size.

A method of wireless communication is described. The method may include determining a bundling configuration for an uplink channel or a downlink channel, receiving a first control format indicator, and communicating according to the first control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

An apparatus for wireless communication is described. The apparatus may include means for determining a bundling configuration for an uplink channel or a downlink channel, means for receiving a first control format indicator, and means for communicating according to the first control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to determine a bundling configuration for an uplink channel or a downlink channel, receive a first control format indicator, and communicate according to the first control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to determine a bundling configuration for an uplink channel or a downlink channel, receive a first control format indicator, and communicate according to the first control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for receiving a second control format indicator in a downlink grant, wherein the first control format indicator is received in system information or higher layer signaling, and wherein the communicating according to the first control format indicator is based at least in part on the second control format indicator.

A method of wireless communication is described. The method may include determining a bundling configuration for an uplink channel or a downlink channel, transmitting a first control format indicator, and communicating according to the first control format indicator or a second control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

An apparatus for wireless communication is described. The apparatus may include means for determining a bundling configuration for an uplink channel or a downlink channel, means for transmitting a first control format indicator, and means for communicating according to the first control format indicator or a second control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to determine a bundling configuration for an uplink channel or a downlink channel, transmit a first control format indicator, and communicate according to the first control format indicator or a second control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to determine a bundling configuration for an uplink channel or a downlink channel, transmit a first control format indicator, and communicate according to the first control format indicator or a second control format indicator based at least in part on the bundling configuration for the uplink channel or the downlink channel.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for transmitting the second control format indicator in a downlink grant, wherein the first control format indicator is transmitted in system information or higher layer signaling.

A method of wireless communication is described. The method may include identifying a downlink bundling configuration and an uplink bundling configuration for a UE, determining a resource configuration for uplink and downlink communications, wherein the resource configuration comprises a first set of resources associated with the downlink bundling configuration interleaved with a second set of resources associated with the uplink bundling configuration, and communicating using the first set of resources or the second set of resources according to the resource configuration.

An apparatus for wireless communication is described. The apparatus may include means for identifying a downlink bundling configuration and an uplink bundling configuration for a UE, means for determining a resource configuration for uplink and downlink communications, wherein the resource configuration comprises a first set of resources associated with the downlink bundling configuration interleaved with a second set of resources associated with the uplink bundling configuration, and means for communicating using the first set of resources or the second set of resources according to the resource configuration.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to identify a downlink bundling configuration and an uplink bundling configuration for a UE, determine a resource configuration for uplink and downlink communications, wherein the resource configuration comprises a first set of resources associated with the downlink bundling configuration interleaved with a second set of resources associated with the uplink bundling configuration, and communicate using the first set of resources or the second set of resources according to the resource configuration.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to identify a downlink bundling configuration and an uplink bundling configuration for a UE, determine a resource configuration for uplink and downlink communications, wherein the resource configuration comprises a first set of resources associated with the downlink bundling configuration interleaved with a second set of resources associated with the uplink bundling configuration, and communicate using the first set of resources or the second set of resources according to the resource configuration.

A method of wireless communication is described. The method may include communicating using a first set of bundled resources for an uplink data channel, determining that a second set of bundled resources for a downlink control channel comprises an uplink grant with a same hybrid automatic repeat request (HARQ) process identifier as the uplink data channel, an uplink grant with a different hybrid automatic repeat request (HARQ) process identifier than the uplink data channel, or a downlink grant, identifying a time difference between the first set of bundled resources and the second set of bundled resources, and communicating using the second set of bundled resources based at least in part on the determining and the identifying.

An apparatus for wireless communication is described. The apparatus may include means for communicating using a first set of bundled resources of an uplink data channel, means for determining that a second set of bundled resources for a downlink control channel comprises an uplink grant with a same hybrid automatic repeat request (HARQ) process identifier as the uplink data channel, an uplink grant with a different HARQ process identifier than the uplink data channel, or a downlink grant, means for identifying a time difference between the first set of bundled resources and the second set of bundled resources, and means for communicating using the second set of bundled resources based at least in part on the determining and the identifying.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to communicate using a first set of bundled resources of an uplink data channel, determine that a second set of bundled resources for a downlink control channel comprises an uplink grant with a same hybrid automatic repeat request (HARQ) process identifier as the uplink data channel, an uplink grant with a different HARQ process identifier than the uplink data channel, or a downlink grant, identify a time difference between the first set of bundled resources and the second set of bundled resources, and communicate using the second set of bundled resources based at least in part on the determination and the identification.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to communicate using a first set of bundled resources of an uplink data channel, determine that a second set of bundled resources for a downlink control channel comprises an uplink grant with a same HARQ process identifier as the uplink data channel, an uplink grant with a different HARQ process identifier than the uplink data channel, or a downlink grant, identify a time difference between the first set of bundled resources and the second set of bundled resources, and communicate using the second set of bundled resources based at least in part on the determination and the identification.

In some examples of the method, apparatuses, or non-transitory computer-readable medium described herein, the first set of bundled resources comprises a first bundling size that is less than or equal to a first threshold and the second set of bundled resources comprises a second bundling size that is less than or equal to a second threshold, and wherein the first and second thresholds are known a priori to a user equipment or base station. Additionally or alternatively, in some examples the determination of whether the second set of bundled resources comprises the uplink grant is based at least in part on a periodicity of the second set of bundled resources or a maximum bundle size of the first set of bundled resources.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for determining that a third set of bundled resources assigned by a grant in the second set of bundled resources overlaps in time with a fourth set of bundled resources for another downlink control channel, wherein communicating using the second set of bundled resources comprises dropping the grant in the second set of bundled resources. Additionally or alternatively, some examples may include processes, features, means, or instructions for determining that the second set of bundled resources comprises the uplink grant with the same HARQ process identifier as the uplink data channel, wherein communicating using the second set of bundled resources comprises dropping the uplink grant based at least on identifying the time difference.

A method of wireless communication is described. The method may include communicating using a first set of bundled resources for an uplink control channel, determining that a second set of bundled resources for a downlink control channel comprises an uplink grant or a downlink grant based at least in part on a time difference between the first set of bundled resources and the second set of bundled resources, and communicating using the second set of bundled resources based at least in part on the determination.

An apparatus for wireless communication is described. The apparatus may include means for communicating using a first set of bundled resources for an uplink control channel, means for determining that a second set of bundled resources for a downlink control channel comprises an uplink grant or a downlink grant based at least in part on a time difference between the first set of bundled resources and the second set of bundled resources, and means for communicating using the second set of bundled resources based at least in part on the determination.

A further apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to communicate using a first set of bundled resources for an uplink control channel, determine that a second set of bundled resources for a downlink control channel comprises an uplink grant or a downlink grant based at least in part on a time difference between the first set of bundled resources and the second set of bundled resources, and communicate using the second set of bundled resources based at least in part on the determination.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable to communicate using a first set of bundled resources for an uplink control channel, determine that a second set of bundled resources for a downlink control channel comprises an uplink grant or a downlink grant based at least in part on a time difference between the first set of bundled resources and the second set of bundled resources, and communicate using the second set of bundled resources based at least in part on the determination.

Some examples of the method, apparatuses, or non-transitory computer-readable medium described herein may further include processes, features, means, or instructions for determining that the second set of bundled resources overlaps in time with the first set of bundled resources, wherein communicating using the second set of bundled resources comprises prioritizing the first set of bundled resources over the second set of bundled resources.

DETAILED DESCRIPTION

Some wireless systems support data communication technologies that allow devices to communicate with one another or a base station without human intervention. This type of communication may be referred to as machine-type communication (MTC), and systems that include MTC devices may employ techniques to facilitate communication with MTC devices. This may include applying coverage enhancement techniques and scheduling or prioritizing resources assignments to MTC devices to account for the device's capability. Wireless communication systems, including those with MTC devices, may support bundling of uplink and downlink resources in a subframe, which may provide coverage enhancements for some devices. A MTC device, for example, may transmit control signals on the uplink and monitor for control signals on the downlink. Additionally, a system may coordinate hybrid automatic repeat request (HARQ) timing with uplink transmissions and downlink monitoring.

A user equipment (UE), such as an MTC device, may be a low complexity, low cost device—relative to other UEs—and may be characterized by features such as low power operation, duplexing capability (e.g., half-duplexing), and operation in environments with poor radio link conditions. A low complexity UE may be referred to as a category 0 UE, and other, more complex UEs may be different categories of UEs. In some cases, techniques or features employed for the purpose of improving operation of MTC may be referred to as enhanced MTC (eMTC). Some MTC UEs may also be configured to operate using a narrow bandwidth, as compared with bandwidth used by other UEs or as compared with a total available system bandwidth. These MTC UEs may use modified DL control channels such as a MTC physical downlink control channel (MPDCCH).

To support MTC, systems may thus be configured to account for operating characteristics of MTC devices, which may be different from other user equipment (UE). This may include broadcasting certain MTC-specific system information using various repetition levels (e.g., bundling) or transport block sizes. These repetition levels may represent the number of retransmissions that a MTC device may receive before decoding the data.

In some cases, a MTC UE may support half duplexing, and may receive downlink and uplink grants simultaneously. So, as discussed below, priority rules may be established for uplink and downlink grants in these cases. Additionally or alternatively, bundled MPDCCH and HARQ may be monitored in a coordinated fashion. In some examples, timing for UL transmissions, DL monitoring, and HARQ processes may also be coordinated.

A wireless system may also use a Control Format Indicator (CFI) to indicate how many orthogonal frequency division multiplexing (OFDM) symbols are used for carrying control channels (e.g., PDCCH, etc.) during each subframe. CFI may be signaled in a system information message, with higher layer signaling, or with dynamic resource grants. In some cases, a MTC UE may receive multiple CFIs and may select the appropriate one based on a bundling configuration.

In some cases, a base station may schedule transmissions for a MTC UE for downlink and uplink with various bundle sizes. A base station may also establish a switching time between narrowband regions, half-duplex switching, or both. In some cases, various resources or types of communications may be prioritized—for instance, an ongoing transmission may receive higher priority (e.g., PUCCH over M-PDCCH, MPDCCH containing ACK over PUSCH, PDSCH over MPDCCH for a grant, etc.). For unicast messages, and as discussed below, even under early termination, timing may be defined for a nominal bundle by counting from the end of the bundle.

Aspects of the disclosure introduced above are described below in the context of an exemplary wireless communication system. Specific examples are then described for timing configuration consistent with MTC operation. These and other aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to bundling operation and hybrid automatic repeat request for enhanced machine-type communication.

FIG. 1illustrates an example of a wireless communications system100in accordance with various aspects of the present disclosure. The wireless communications system100includes base stations105, UEs115, and a core network130. In some examples, the wireless communications system100may be a Long Term Evolution (LTE)/LTE-Advanced (LTE-A) network. Wireless communications system100may support MTC operations, including timing configurations based on half-duplex operation and transmission bundling.

Base stations105may wirelessly communicate with UEs115using one or more base station antennas. Each base station105may provide communication coverage for a respective geographic coverage area110. Communication links125shown in wireless communications system100may include uplink (UL) transmissions from a UE115to a base station105, or downlink (DL) transmissions, from a base station105to a UE115. UEs115may be dispersed throughout the wireless communications system100, and each UE115may be stationary or mobile. A UE115may also be referred to as a mobile station, a subscriber station, a remote unit, a wireless device, an access terminal, a handset, a user agent, a client, or some other suitable terminology. A UE115may also be a cellular phone, a wireless modem, a handheld device, a personal computer, a tablet, a personal electronic device, an MTC device or the like.

As mentioned above, some types of wireless devices may provide for automated communication, including those implementing Machine-to-Machine (M2M) communication or MTC. M2M or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to users interacting with the program or application. Some UEs115may be MTC devices, such as those designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices may include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging. A MTC device may operate using half-duplex (one-way) communications at a reduced peak rate. MTC devices may also be configured to enter a power saving “deep sleep” mode when not engaging in active communications, during which they may power off some componentry for relatively long periods of time (e.g., tens of milliseconds, hundreds of milliseconds, seconds, minutes, or the like).

Time resources may be organized according to radio frames of length of 10 ms, which may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include ten 1 ms subframes numbered from 0 to 9. A subframe may be further divided into two 0.5 ms slots, each of which contains 6 or 7 modulation symbol periods (depending on the length of the cyclic prefix prepended to each symbol). Excluding the cyclic prefix, each symbol contains 2048 sample periods. In some cases the subframe may be the smallest scheduling unit, also known as a TTI. In other cases, a TTI may be shorter than a subframe or may be dynamically selected (e.g., in short TTI bursts or in selected component carriers using short TTIs). In some cases, time intervals in LTE may be expressed in multiples of a basic time unit (e.g., the sampling period, Ts=1/30,720,000 seconds).

A TTI (e.g., 1 ms in LTE, the equivalent of one subframe) may be defined as the smallest unit of time in which a base station105may schedule a UE115for UL or DL transmission. For example, if a UE115is receiving DL data, then during each 1 ms interval a base station105may assign resources and indicate (via PDCCH transmissions) to the UE115where to look for its DL data. If a transmission is unsuccessful, a UE115(or a base station105) may respond with a negative acknowledgment (NACK) in accordance with a HARQ procedure. In some cases, HARQ procedures may result in multiple retransmissions of data, which may result in delays and an impaired user experience. The degradation in service may be particularly significant in poor radio conditions (e.g., near the edge of a cell). The degradation may not be acceptable for certain time-sensitive user services such as VoIP (or VoLTE). TTI bundling may be used to improve communication link125in such radio conditions. TTI bundling may involve sending multiple copies of the same information in a group of consecutive subframes (TTIs) rather than waiting for a NACK before retransmitting redundancy versions as in typical HARQ operation.

HARQ may be a method of ensuring that data is received correctly over a communication link125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the medium access control (MAC) layer in poor radio conditions (e.g., signal-to-noise conditions). In Incremental Redundancy HARQ, incorrectly received data may be stored in a buffer and combined with subsequent transmissions to improve the overall likelihood of successfully decoding the data. In some cases, redundancy bits are added to each message prior to transmission. This may be especially useful in poor conditions. In other cases, redundancy bits are not added to each transmission, but are retransmitted after the transmitter of the original message receives a negative acknowledgement (NACK) indicating a failed attempt to decode the information. The chain of transmission, response and retransmission may be referred to as a HARQ process. In some cases, a limited number of HARQ processes may be used for a given communication link125. For MTC devices, HARQ timing combined with bundling and half-duplex operation may impact scheduling and prioritization of transmissions. For example, PDCCH and PUCCH grants may be prioritized by an MTC UE115.

PDCCH may carry downlink control information (DCI) in control channel elements (CCEs), which may consist of nine logically contiguous resource element groups (REGs), where each REG contains 4 resource elements (REs). DCI includes information regarding downlink (DL) scheduling assignments, uplink (UL) resource grants, transmission scheme, UL power control, HARQ information, modulation and coding scheme (MCS) and other information. The size and format of the DCI messages can differ depending on the type and amount of information that is carried by the DCI. For example, if spatial multiplexing is supported, the size of the DCI message is large compared to contiguous frequency allocations. Similarly, for a system that employs multiple input multiple output (MIMO), the DCI may include additional signaling information. DCI size and format depend on the amount of information as well as factors such as bandwidth, the number of antenna ports, and duplexing mode. PDCCH can carry DCI messages associated with multiple users, and each UE115may decode the DCI messages that are intended for it. For example, each UE115may be assigned a cell radio network temporary identity (C-RNTI) and CRC bits attached to each DCI may be scrambled based on the C-RNTI.

To reduce power consumption and overhead at the user equipment, a limited set of CCE locations can be specified for DCI associated with a specific UE115. CCEs may be grouped (e.g., in groups of 1, 2, 4 and 8 CCEs), and a set of CCE locations in which the user equipment may find relevant DCI may be specified. These CCEs may be known as a search space. The search space can be partitioned into two regions: a common CCE region or search space and a UE-specific (dedicated) CCE region or search space. The common CCE region is monitored by all UEs served by a base station105and may include information such as paging information, system information, random access procedures and the like. The UE-specific search space may include user-specific control information. CCEs may be indexed, and the common search space may start from CCE 0. The starting index for a UE specific search space depends on the C-RNTI, the subframe index, the CCE aggregation level and a random seed. A UE115may attempt to decode DCI by performing a process known as a blind decode, during which search spaces are randomly decoded until the DCI is detected. During a blind decode, the UE115may attempt to descramble all potential DCI messages using its C-RNTI, and perform a CRC check to determine whether the attempt was successful.

PUCCH may be used for UL acknowledgements (ACKs), scheduling requests (SRs) and channel quality indicators (CQI), and other UL control information. A physical uplink control channel (PUCCH) may be mapped to a control channel defined by a code and two consecutive resource blocks. UL control signaling may depend on the presence of timing synchronization for a cell. PUCCH resources for scheduling request (SR) and channel quality indicator (CQI) reporting may be assigned (and revoked) through radio resource control (RRC) signaling. In some cases, resources for SR may be assigned after acquiring synchronization through a random access channel (RACH) procedure. In other cases, an SR may not be assigned to a UE115through the RACH (i.e., synchronized UEs may or may not have a dedicated SR channel). PUCCH resources for SR and CQI may be lost when the UE is no longer synchronized.

Wireless communications system100may include a radio link control (RLC) layer that connects higher layers (e.g., RRC and packet data convergence protocol (PDCP)) to the lower layers (e.g., the MAC layer). An RLC entity in a base station105or a UE115may ensure that transmission packets are organized into appropriately sized blocks (corresponding to the MAC layer transport block size). If an incoming data packet (i.e., a PDCP or RRC service data unit (SDU)) is too big for transmission, the RLC layer may segment it into several smaller RLC protocol data unit (PDUs). If the incoming packets are too small, the RLC layer may concatenate several of them into a single, larger RLC PDU. Each RLC PDU may include a header including information about how to reassemble the data. The RLC layer may also ensure that packets are reliably transmitted. The transmitter may keep a buffer of indexed RLC PDUs, and continue retransmission of each PDU until it receives the corresponding acknowledgement (ACK). In some cases, the transmitter may send a Poll Request to determine which PDU's have been received and the receiver may respond with a Status Report.

Unlike the MAC layer HARQ, RLC automatic repeat request (ARQ) may not include a forward error correction function. A RLC entity may operate in one of three modes. In acknowledged mode (AM), unacknowledged mode (UM) and transparent mode (TM). In AM, the RLC entity may perform segmentation/concatenation and ARQ. This mode may be appropriate for delay tolerant or error sensitive transmissions. In UM, the RLC entity may perform segmentation/concatenation but not ARQ. This may be appropriate for delay sensitive or error tolerant traffic (e.g., voice over Long Term evolution (VoLTE)). TM performs data buffering, and does not include either concatenation/segmentation or ARQ. TM may be used primarily for sending broadcast control information (e.g., the master information block (MIB) and system information block (SIBs)), paging messages, and RRC connection messages. Some transmissions may be sent without RLC (e.g., a RACH preamble and response).

Carriers may transmit bidirectional communications (e.g., using communications links125) using frequency division duplex (FDD) (e.g., using paired spectrum resources) or time division duplex (TDD) operation (e.g., using unpaired spectrum resources). Frame structures for FDD (e.g., frame structure type1) and TDD (e.g., frame structure type2) may be defined. For TDD frame structures, each subframe may carry UL or DL traffic, and special subframes may be used to switch between DL and UL transmission. Allocation of UL and DL subframes within radio frames may be symmetric or asymmetric and may be statically determined or may be reconfigured semi-statically. Special subframes may carry DL or UL traffic and may include a Guard Period (GP) between DL and UL traffic. Switching from UL to DL traffic may be achieved by setting a timing advance at the UE115without the use of special subframes or a guard period. UL-DL configurations with switch-point periodicity equal to the frame period (e.g., 10 ms) or half of the frame period (e.g., 5 ms) may also be supported. For example, TDD frames may include one or more special frames, and the period between special frames may determine the TDD DL-to-UL switch-point periodicity for the frame.

Use of TDD may offer flexible deployments without paired UL-DL spectrum resources. In some TDD network deployments, interference may be caused between UL and DL communications (e.g., interference between UL and DL communication from different base stations, interference between UL and DL communications from base stations and UEs, etc.). For example, where different base stations105serve different UEs115within overlapping coverage areas according to different TDD UL-DL configurations, a UE115attempting to receive and decode a DL transmission from a serving base station105can experience interference from UL transmissions from other, proximately located UEs115.

A UE115, such as a half-duplex capable MTC device, may receive grants for overlapping uplink and downlink resources. The UE115may then prioritize the grants and either drop or, in some cases, monitor the non-overlapping portion of the low priority channel associated with a grant. The UE115may also determine an acknowledgement mode for the downlink transmission based on one or more grants or on an explicit indication from a base station105. A control format indicator (CFI) may also be interpreted based on the grant or on the bundling size. In some cases, the UE115may also identify a retuning time and may determine uplink and downlink bundling sizes accordingly.

FIG. 2illustrates an example of a wireless communications system200for bundling operation and hybrid automatic repeat request for enhanced machine-type communication in accordance with various aspects of the present disclosure. Wireless communications system200may include a UE115-aand a base station105-a, which may be examples of a UE115and base station105described with reference toFIG. 1. Wireless communications system200may support MTC operations, including timing configurations based on half-duplex operation and transmission bundling.

Wireless communications system200may support MTC operations to enable operation of low cost and low complexity devices. For example, in the context of LTE systems, these low cost UEs or MTC UEs115may be referred to as category 0 UEs, which may be characterized by reduced peak data rates (e.g., a possible maximum of 1000 bits for a transport block size), rank one transmission, one receive antenna, and, if half-duplex, relaxed switching timing (from transmission to reception or vice versa) from, for example, 20 μs for regular UEs to 1 ms for MTC UEs. These MTC UEs115may monitor DL control channels in a manner similar to other UEs115, including PDCCH and MTC PDCCH (MPDCCH).

Additional MTC enhancements (referred to as eMTC in some cases) may be supported as well. For example, narrowband operation may be supported, such that MTC UE115-amay be able to operate in a wider system bandwidth. The system200may support operation in multiple system bandwidth ranges (e.g., 1.4/3/5/10/15/20 MHz) using 1.4 MHz or 6 RBs, as described above. Additionally, wireless communications systems may support coverage enhancements up to 15 dB.

MTC UE115-amay support half duplexing (HD) where communication is possible in two directions (e.g., uplink and downlink) but in one direction at a time (e.g., uplink or downlink). Frequency Division Duplexing (FDD) HD, for instance, supports transmission and reception of signals in one direction at a time using two different frequencies. Time Division Duplexing (TDD) HD may support transmitting a short amount of data in separate timeslots, in one direction at a time. MTC UE115-amay support FDD HD and TDD HD for communication with base station105-a.

Wireless communications system200may also support or employ a common search space where Control Channel Elements (CCEs) are allocated and used for communicating control information for a group of UEs. Information on the CCE aggregation level and the number of repetition for data transmission may be fixed in the specification or configured by the network. In some cases, a subset of these resources may be semi-statically configured for constructing a UE-specific search space for MPDCCH by higher-layer signaling. In these cases, UE-specific CCEs can be decoded by a specific UE (e.g., UE115-a), and a predetermined number of repetitions may be specified for the UE. Also, a starting subframe of an M-PDCCH UE-specific search space may be configured for enhanced coverage.

Wireless communications system200, in some examples, may support a frame and subframe structure in which a frame includes 10 subframes. MTC UE115-amay monitor for messages from base station105-ain a set of subframes of a frame, and may transmit messages to base station105-ain another set of subframes of the same frame, a different frame, or both. In some cases, MTC UE115-amay support half duplexing, and may receive downlink and uplink grants simultaneously. In these cases, priority rules may be established for the uplink and downlink grants. Additionally, in some cases, bundled MPDCCH monitoring is combined with HARQ monitoring, and timing for UL transmissions, DL monitoring, and HARQ processes are coordinated.

By way of example, for FDD HD, if uplink and downlink are bundled, then PUSCH and PDSCH assignments may overlap in time. For example, MTC UE115-amay receive a downlink grant, indicated to begin at subframe N, and an uplink grant, indicated to begin at subframe N+4, both with a bundle size of 8. This type of operation may be unsupported in HD mode. Alternatively, if the bundle size for DL is small (e.g.,2), there may be time to retune to uplink and base station105-amay transmit both grants in the same subframe.

For FDD with long bundle sizes, base station105-amay be configured to not transmit both grants in the same subframe. For example, if aggregation level24is monitored, base station105-amay send one grant. For TDD with long bundle sizes, transmission of UL messages and reception of DL messages may be combined. Additionally, if MTC UE115-areceives both DL and UL grants that overlap, it may be appropriate to signal rules for MTC UE115-a. In some cases, one of the grants may be dropped (e.g., keep DL, drop UL), and, in other cases, one grant or may receive priority (e.g., finish the UL transmission before monitoring for DL messages).

MTC UE115-amay transmit an uplink message and then monitor for downlink messages using, for example, MPDCCH. In these cases, the system200may account for time between UL transmission and DL monitoring for MTC UE115-ato retune (e.g., lms for FDD and 1-3 symbols for TDD) aspects of its RF chain. Alternatively, for FDD HD, MTC UE115-amay be configured to not monitor MPDCCH when there is insufficient time to retune. Also, MTC UE115-amay use a shortened bundle size for either PUSCH or MPDCCH to allow time to retune.

For TDD, MTC UE115-amay monitor MPDCCH when in the same narrowband as PUSCH. If narrowband allocations for DL and UL are different, MTC UE115-amay discard the MPDCCH grant. Additionally, MTC UE115-amay monitor for a full format if the same narrowband is used, and a shortened format if a different narrowband is used. For example, a shortened format may include a subframe with3control symbols for retuning. In some cases, the full format may include the signaled number of control symbols. Base station105-amay also be configured to schedule MPDCCH and PUSCH grants so as to allow time for retuning between transmissions and monitoring.

The transmission of PUCCH for HARQ feedback may reduce the downlink data rate. In some cases, the reduction in downlink data rate may be significant. MTC UE115-amay thus rely on MAC processes instead of HARQ processes when there is low or an acceptably low likelihood of error in a communication system. In some cases, a bundle size for PUCCH may be signaled to MTC UE115-a. Base station105-amay indicate, e.g., in a DL grant, whether MTC UE115-ashould send an ACK/NAK. If an ACK/NAK is requested, base station105-amay indicate the repetition length for the PUCCH. Alternatively, the bundling length of PUCCH may be included with MPDCCH or the corresponding PDSCH transmission, whose bundling length may be dynamic. Also, the PUCCH resource may be implicitly or explicitly signaled. For example, MTC UE115-amay be configured with4PUCCH resources, each one with a different bundle size. As such, the DL grant may include 2 bits to select one of these resources.

Wireless communications system200may support a CFI used to indicate how many OFDM symbols (e.g., control symbols) are used for carrying control channels (e.g., PDCCH, etc.) at each subframe. MTC UE115-amay determine that those symbols carrying control channels are unusable for the MTC UE115-a—e.g., because the control symbols use a wide frequency band, while the MTE UE115-ais capable of narrowband operation. MTC UE115-amay thus refrain from monitoring during symbols signaled or indicated to contain PDCCH.

The number of control symbols may be signaled by system information (e.g., SIB1) or higher layer signaling (e.g., RRC signaling). For example, a cell may signal 2 control symbols if the cell is configured to or otherwise supports use of one or two control symbols. When one control symbol is used, OFDM symbol may be wasted if a UE115expects that additional control symbols include control information. So, in some cases, if a cell signals CFI=1, then there may be less flexibility for base station105-ato include more control symbols, but also there may be fewer unused resources.

In some cases, system200, through base station105-a, may coordinate resources and grants for MTC UE115-abased on the CFI. In some examples, an MTC UE115-awith a large bundle size may follow the signaled CFI. Base station105-amay signal the CFI in a downlink grant for UE115-ain normal coverage. For example, system information block 1 (SIB1) may contain CFI=3, but DCI may contain the true CFI (e.g., CFI=1). In some cases, MPDCCH may be decoded based on the CFI signaled in SIB1. In such cases, the corresponding PDSCH may use the CFI signaled in the grant. Additionally, CFI may be signaled in a grant, but may not depend on the value in SIB1. For example, if SIB1 signals CFI=1, DCI may not include CFI so the minimum value may be 1. Also, the signaling may be 1 bit, and the final CFI value may depend on the SIB1 value. For example, if SIB1=1 then there may be no signaling in DCI, if SIB1=2 then DCI may select between 1 and 2, and if SIB1=3 then DCI may select between 2 and 3.

By way of example, for TDD, simultaneous bundled uplink and downlink channels may be supported (e.g., transmitting PUSCH and monitoring MPDCCH simultaneously). Additionally or alternatively, system200and base station105-aor MTC UE115-amay employ rules for reducing the number of subframes used when monitoring MPDCCH. For example, if a PUSCH transmission is ongoing, and decoding MPDCCH grant schedules PUSCH that overlaps in time with ongoing PUSCH, then the MPDCCH grant may be discarded. Further, base station105-amay be configured to avoid sending UL grants for PUSCH that may overlap with current PUSCH transmission.

In FDD configurations, the time between uplink scheduling may not, without additional coordination by system200, correspond with HARQ timing. For example, the starting MPDCCH subframe may be every 10 subframes, the MPDCCH bundle size may be 6, and the PUSCH bundle size may be 9. So the time between PUSCH transmission and MPDCCH monitoring may not correspond to HARQ timing.

If uplink scheduling does not correspond with HARQ timing, the starting subframe for MPDCCH may allow for HARQ timing, for example. Additionally, MPDCCH may be monitored in cases when HARQ timing may not be met. Alternatively, if no ACK is transmitted (e.g., grant-based HARQ), the MPDCCH starting at a subframe before the end of the HARQ process may not schedule the same HARQ process. For asynchronous HARQ processes, MTC UE115-amay receive a grant with the same HARQ ID as the previous transmission. In these cases, it may be appropriate to prune out the grant, or follow the grant.

In some examples, for downlink, after PDSCH reception, MTC UE115-amay transmit PUCCH. In such cases, the next MPDCCH may not meet HARQ timing after the PUCCH transmission. If the second monitoring instant (e.g., MPDCCH) is right after PUCCH, base station105-amay not have time to process PUCCH to decide on the MPDCCH grant. In such cases, it may be appropriate to count from the end of the bundle to ensure sufficient processing time. Further, MTC UE115-amay be configured to not schedule the same HARQ process from an MPDCCH. However, if MTC UE115-aschedules the same HARQ process from the MPDCCH, MTC UE115-amay either follow or discard the grant. In such cases, base station105-amay reuse the same HARQ process.

In some cases, such as for some downlink communications, MTC UE115-amay monitor MPDCCH every 10 subframes. If an MPDCCH schedules PDSCH, it may overlap with PUCCH of the previous PDSCH. Further, if the MPDCCH schedules PUSCH, it may also overlap with PUCCH of the previous PDSCH. In these cases, the PUCCH transmission may be given priority. MTC UE115-amay drop any assignment that may overlap with PUCCH (e.g., half duplex FDD MTC UE115-a).

Thus, base station105-amay schedule transmissions for MTC UE115-afor DL and UL with various bundle sizes. Also, base station105-amay establish a switching time between narrowband regions, half duplex switching, or both. In some cases, for HARQ processes performed over MPDCCH in a first monitoring instant, the ACK/NAK message may be transmitted in the next monitoring instant. Further, an ongoing transmission may receive higher priority (e.g., PUCCH over M-PDCCH, MPDCCH containing ACK over PUSCH, PDSCH over MPDCCH for a grant, etc.). For unicast messages, including those under early termination, the timing may be defined for a nominal bundle by counting from the end of the bundle. For example, if MTC UE115-ais able to decode PDSCH in 4 subframes, and the bundle size is 8, the HARQ timing and application of rules may be done by assuming 8 subframes.

FIGS. 3A, 3B, 3C, 3D and 3Eillustrate example bundling and HARQ operation timing schemes300-a,300-b,300-c,300-d, and300-ethat support uplink transmissions and downlink monitoring for MTC in accordance with various aspects of the present disclosure. Timing schemes300-a,300-b,300-c,300-d, and300-emay be based on a bundling scheme for a MTC device consistent with HARQ timing and control channel scheduling and may illustrate methods to avoid overlapping of uplink and downlink processes.

As depicted inFIG. 3A, timing scheme300-amay represent back-to-back transmission of downlink and uplink channels for MTC. During MPDCCH period305-a, a device may monitor MPDCCH in a first set of subframes. Additionally, a device may identify a scheduled gap310-ato switch between a transmitting mode and a receiving mode based on a half-duplex communication capability. The device may receive a first grant for a set of resources (e.g., at PUSCH period315-a), and may have to monitor a second set of resources (e.g., during MPDCCH period310-b). In some cases, the device may determine that a portion of the first set of resources overlaps with a portion of the second set of resources or with the scheduled gap310-a. Additionally, the device may determine that the second set of resources is contiguous to the first set of resources, so the device may not have time to retune from a transmitting mode to a receiving mode. In some cases, the device may determine a first bundling size for PUSCH period315-a, and may determine a second bundling size for MPDCCH period310-bbased on the retuning time. The device may then communicate according to the retuning time and the first bundling size or the second bundling size.

Thus, the device may communicate using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant. This prioritization may include dropping the first grant or the second grant. The device may also communicate using the first set of resources and a non-overlapped portion of the second set of resources. For example, the UE might communicate using the whole of the first set of resources, but a subset of the second set of resources (e.g. by monitoring subframes1-5in310-b). The first and second sets of resources may include bundled resources of an uplink channel or a downlink channel.

In some cases, a device may determine that MPDCCH overlaps with the retuning time for a frequency division duplexing (FDD) configuration. As such, the device may refrain from decoding an MPDCCH. In some cases, the first bundling size or the second bundling size may be reduced from a nominal bundling size based on the retuning time.

The device may also determine whether PUSCH period315-aand MPDCCH period310-binclude scheduled resources with frequencies in the same narrowband region. In some examples, MPDCCH may be decoded when PUSCH and MPDCCH include frequency resources of the same narrowband region. In some cases, the first bundling size or the second bundling size may be based on whether PUSCH and MPDCCH include frequency resources of the same narrowband region. Additionally, a starting time for MPDCCH may be based on the retuning time and the first bundling size.

Timing scheme300-bofFIG. 3Bmay represent interleaved uplink and downlink bundling for a device. The device may identify a downlink bundling configuration and an uplink bundling configuration. The device may then determine a resource configuration for uplink and downlink communications. In some cases, the resource configuration may include a first set of resources associated with the downlink bundling configuration (e.g., at MPDCCH periods305-c) interleaved with a second set of resources associated with the uplink bundling configuration, (e.g., at PUSCH periods315-b). The device may then communicate using the first set of resources or the second set of resources according to the resource configuration. In some cases, the MPDCCH monitoring and the PUSCH transmissions may be separated by a guard band320.

Additionally, the device may determine a bundling configuration for an uplink channel or a downlink channel. The device may receive a first CFI, and communicate according to the first CFI based on the bundling configuration for PUSCH periods315-cor MPDCCH periods305-dand305-e. The device may receive a second CFI in a downlink grant, and may receive the first CFI in system information or higher layer signaling. In such cases, the device may communicate according to the first CFI based on the second CFI.

Timing scheme300-cofFIG. 3Cmay represent uplink and downlink scheduling where HARQ timing may be uncoordinated with MPDCCH monitoring and PUSCH transmissions. A device may receive a grant for a downlink transmission during MPDCCH period305-dand may determine an acknowledgement mode for the downlink transmission based on the grant. In some cases, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for MPDCCH period305-d, and an indication of a bundling configuration for the acknowledgement message.

In some examples, for FDD, the starting MPDCCH subframe may be every 10 subframes (e.g., between MPDCCH period305-dand MPDCCH period305-e), and at scheduled gap310-cthe time between PUSCH periods315-cand MPDCCH period305-emay not correspond to HARQ timing. If uplink scheduling does not correspond with HARQ timing, the starting subframe for MPDCCH period305-emay be modified to allow for HARQ timing. For example, if the MPDCCH bundle size is 2 and the maximum PUSCH bundle size is 10, the total timing may be 2 (from MPDCCH)+3 (from retuning/scheduling timing)+10 (from PUSCH)+3 (for HARQ timing), and the MPDCCH period may be greater than 18 subframes (not shown). In other cases, a device may support different MPDCCH monitoring subframes for uplink and downlink. In some examples, if the MPDCCH bundle size is 2 and the maximum PUSCH bundle size is 10, the total timing for an uplink cycle may be greater than 18 subframes, and the total timing for a downlink cycle may be 10 subframes (e.g., 2 (MPDCCH)+2 (PDSCH)+3 (HARQ timing)+3 (PUCCH)). Accordingly, the device may monitor MPDCCH for downlink every 10 ms and MPDCCH for uplink every 20 ms.

Additionally, a device may monitor MPDCCH in cases when HARQ timing may not be met. For example, at scheduled gap310-c, the time between PUSCH period315-c(e.g., starting at subframe N) and MPDCCH period305-e(e.g., starting at subframe N+K) may be less than HARQ timing (e.g., K<KHARQ). In such cases, if an explicit ACK is expected for PUSCH315-c, it may be transmitted at MPDCCH period305-f(in the next monitoring instant). Further, if MPDCCH period305-econtains a PDSCH assignment that overlaps with MPDCCH period305-f, the device may ignore the assignment. In some cases, a base station may be configured to refrain from simultaneous transmission of MPDCCH and unassociated PDSCH.

Alternatively, if no ACK is transmitted (e.g., grant-based HARQ), the MPDCCH period305-emay not schedule the same HARQ process. For asynchronous HARQ processes, a device may receive a grant with the same HARQ ID as the previous transmission. In such cases, it may be appropriate to prune out or follow the grant. As for synchronous HARQ processes, MPDCCH period305-dmay schedule a different HARQ process (e.g., for at least 2 HARQ processes).

This bundling configuration for the acknowledgement message may be based on a bundling configuration for the grant. Additionally, the grant may include an indication of resources for an acknowledgement messages. In some cases, the time between PUSCH period315-cand MPDCCH period305-eat scheduled gap310-cmay not be coordinated with HARQ timing. As such, the resources for the acknowledgement message may be determined based on the grant and a bundling size.

In other cases, a scheduling device may determine an acknowledgement mode for a downlink transmission based on a channel condition, and transmit a grant to assign resources for the downlink transmission (i.e., MPDCCH) that includes an indication of the acknowledgement mode. The grant may also include an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission, and a bundling configuration for the acknowledgement message.

The bundling configuration for the acknowledgement message may be based on a bundling configuration for the grant. The grant may also include an indication of resources for an acknowledgement message. In some examples, the resources for the acknowledgement may be based on the grant and bundling size.

Timing scheme300-dofFIG. 3Dmay represent uplink and downlink scheduling where a set of resources used to transmit PUCCH may overlap with or be contiguous to a set of resources used to monitor MPDCCH. At PDSCH period316-a, a device may communicate using a first set of bundled resources for PDSCH. The device may determine that a second set of bundled resources for MPDCCH period305-gincludes an uplink grant with a same HARQ process identifier as PDSCH, an uplink grant with a different HARQ process identifier than PDSCH, or a downlink grant based on a time difference between the first set of bundled resources and the second set of bundled resources. The device may then communicate using the second set of bundled resources based on the determination.

In some examples, for downlink, after PDSCH reception, an MTC may transmit PUCCH at325-a. In such cases, the MPDCCH period305-hmay not meet HARQ timing after the PUCCH transmission. For example, the starting subframe may be every 10 subframes, the bundle size may be 4 for MPDCCH periods305-gand305-h, the bundle size may be 8 for PDSCH period316-a, and the PUCCH period325-abundle size (e.g., used to send ACK) may be 4. If the second monitoring instant at MPDCCH period305-his right after PUCCH period325-a, a base station105may not have time to process PUCCH to decide on the MPDCCH grant. In such cases, it may be appropriate to count from the end of the bundle to ensure sufficient processing time. Further, a MTC may be configured to refrain from scheduling the same HARQ process from MPDCCH period305-g. However, if a device schedules the same HARQ process from MPDCCH period305-g, the device may either follow or discard the grant. In such cases, a base station may reuse the same HARQ process.

A device may determine that a third set of bundled resources assigned by a grant in the second set of bundled resources at PUCCH period325-aoverlaps in time with a fourth set of bundled resources for MPDCCH period305-h. In such cases, the device may drop the grant in the second set of bundled resources. Additionally, the device may determine that the second set of bundled resources includes the uplink grant with the same HARQ process identifier as a PDSCH. As such, the device may drop the uplink grant.

Timing scheme300-eofFIG. 3Emay represent uplink and downlink scheduling where a device may monitor MPDCCH using separate sets of subframes. At PUCCH period325-b, a device may communicate using a first set of bundled resources for PUCCH. The device may determine that a second set of resources for MPDCCH period305-jincludes an uplink grant or a downlink grant based on a time difference between the first set of bundled resources and the second set of bundled resources. This uplink grant indicates the communication over a third set of resources (not shown in Figure), e.g. to transmit PUSCH or to receive PDSCH. In some cases, the device may determine that the second set of bundled resources overlaps in time with the first set of bundled resources at PUCCH period325-b(or a scheduled gap310-e), and may prioritize the first set of bundled resources over the second set of bundled resources.

In some examples, a device may monitor MPDCCH every 10 subframes. For example, if MPDCCH period305-ischedules PUSCH, it may overlap with PUCCH period325-bof the previous PDSCH. Further, if MPDCCH period305-ior305-jschedules PUSCH (not shown), it may also overlap with PUCCH period325-bof the previous PDSCH. In such cases, PUCCH period325-bmay be given priority. The device may drop any assignment that may overlap with PUCCH period325-b(e.g., half duplex FDD).

In some cases, a first set of bundled resources may include a first bundling size that is less than or equal to a first threshold, and the second set of resources includes a second bundling size that is less than or equal to a second threshold. In some cases, the first and second thresholds may be known a priori to the device or a base station. Additionally, the determination of whether the second set of bundled resources includes the uplink grant may be based on a periodicity of the second set of bundled resources or a maximum bundle size of the first set of bundled resources.

FIG. 4shows a block diagram of a wireless device400that supports bundling and HARQ operation for enhanced machine-type communication in accordance with various aspects of the present disclosure. Wireless device400may be an example of aspects of a UE115described with reference toFIGS. 1-3. Wireless device400may include a receiver405, a half-duplex timing module410, or a transmitter415. Wireless device400may also include a processor. Each of these components may be in communication with one another.

The receiver405may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to bundling operation and hybrid automatic repeat request for enhanced machine-type communication, etc.). Information may be passed on to the half-duplex timing module410, and to other components of wireless device400.

The half-duplex timing module410, in combination with receiver405for instance, may receive a first grant for a first set of resources, receive a second grant for a second set of resources, determine that a portion of the first set of resources overlaps with a portion of the second set of resources, and communicate using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant.

The transmitter415may transmit signals received from other components of wireless device400. In some examples, the transmitter415may be collocated with the receiver405in a transceiver module. The transmitter415may include a single antenna, or it may include a plurality of antennas.

FIG. 5shows a block diagram of a wireless device500that supports bundling and HARQ operation for enhanced machine-type communication in accordance with various aspects of the present disclosure. Wireless device500may be an example of aspects of a wireless device400or a UE115described with reference toFIGS. 1-4. Wireless device500may include a receiver405-a, a half-duplex timing module410-a, or a transmitter415-a. Wireless device500may also include a processor. Each of these components may be in communication with one another. The half-duplex timing module410-amay also include a resource identification module505, an overlap identification module510, and a communication module515.

The receiver405-amay receive information which may be passed on to half-duplex timing module410-a, and to other components of wireless device500. The half-duplex timing module410-amay perform the operations described with reference toFIG. 4. The transmitter415-amay transmit signals received from other components of wireless device500.

The resource identification module505may, in combination with receiver405-a, receive various signals. The resource identification module505may receive a first grant for a first set of resources as described with reference toFIGS. 2-3. The resource identification module505may also receive a second grant for a second set of resources. The resource identification module505may, in some cases, drop the first grant or the second grant based on the prioritization. In some examples, the first and second sets of resources each includes bundled resources of an uplink channel or a downlink channel. The resource identification module505may also determine for a TDD configuration whether the uplink data channel and the downlink control channel includes frequency resources of a same narrowband region.

The resource identification module505may also receive a grant for a downlink transmission. The resource identification module505may, in combination with transmitter415-afor instance, transmit a grant to assign resources for the downlink transmission including an indication of the acknowledgement mode. The resource identification module505may also determine a resource configuration for uplink and downlink communications including a first set of resources associated with the downlink bundling configuration interleaved with a second set of resources associated with the uplink bundling configuration. The resource identification module505may also determine that a second set of bundled resources for a downlink control channel includes an uplink grant with a same HARQ process identifier as the uplink data channel, an uplink grant with a different HARQ process identifier than the uplink data channel, or a downlink grant based on a time difference between the first set of bundled resources and the second set of bundled resources.

In some examples, the first set of bundled resources includes a first bundling size that is less than or equal to a first threshold and the second set of bundled resources includes a second bundling size that is less than or equal to a second threshold. In some cases, the first and second thresholds are known a priori to a user equipment or base station. In some examples, the determination of whether the second set of bundled resources includes the uplink grant may be based on a periodicity of the second set of bundled resources or a maximum bundle size of the first set of bundled resources. The resource identification module505may also determine that a third set of bundled resources assigned by a grant in the second set of bundled resources overlaps in time with a fourth set of bundled resources for another downlink control channel, where communicating using the second set of bundled resources includes dropping the grant in the second set of bundled resources.

The resource identification module505may also determine that the second set of bundled resources includes the uplink grant with the same HARQ process identifier as the uplink data channel, where communicating using the second set of bundled resources includes dropping the uplink grant. The resource identification module505may also determine that a second set of bundled resources for a downlink control channel includes an uplink grant or a downlink grant based on a time difference between the first set of bundled resources and the second set of bundled resources.

The overlap identification module510may determine that a portion of the first set of resources overlaps with a portion of the second set of resources as described with reference toFIGS. 2-3. The overlap identification module510may also determine for a frequency division duplexing (FDD) configuration that the downlink control channel overlaps with the retuning time, where the communicating includes refraining from decoding the downlink control channel. The overlap identification module510may also determine that the second set of bundled resources overlaps in time with the first set of bundled resources, where communicating using the second set of bundled resources includes prioritizing the first set of bundled resources over the second set of bundled resources.

The communication module515may, in combination with receiver405-aor transmitter415-a, or both, communicate using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant as described with reference toFIGS. 2-3. In some examples, communicating using the first set of resources or the second set of resources includes communicating using the first set of resources and a non-overlapped portion of the second set of resources. The communication module515may also communicate according to the retuning time and the first bundling size or the second bundling size. In some examples, the communicating includes decoding the downlink control channel when the uplink data channel and the downlink control channel includes frequency resources of the same narrowband region. The communication module515may also communicate according to the first control format indicator based on the bundling configuration for the uplink channel or the downlink channel.

The communication module515may communicate according to the first control format indicator or a second control format indicator based on the bundling configuration for the uplink channel or the downlink channel. The communication module515may also communicate using the first set of resources or the second set of resources according to the resource configuration. The communication module515may also communicate using a first set of bundled resources for an uplink data channel. The communication module515may also communicate using the second set of bundled resources based on the determination. The communication module515may also communicate using a first set of bundled resources for an uplink control channel. In some cases, the communication module515communicates using the second set of bundled resources based on the determination.

FIG. 6shows a block diagram600of a half-duplex timing module410-bwhich may be a component of a wireless device400or a wireless device500that supports bundling and HARQ operation for enhanced machine-type communication in accordance with various aspects of the present disclosure. The half-duplex timing module410-bmay be an example of aspects of a half-duplex timing module410described with reference toFIGS. 4-5. The half-duplex timing module410-bmay include a resource identification module505-a, an overlap identification module510-a, and a communication module515-a. Each of these modules may perform the functions described with reference toFIG. 5. The half-duplex timing module410-bmay also include a retuning module605, a bundling module610, an acknowledgement mode module615, and a channel format indicator (CFI) module620.

The retuning module605may identify a retuning time for a UE to switch between a transmitting mode and a receiving mode based on a half-duplex communication capability of the UE as described with reference toFIGS. 2-3. In some examples, a starting time for the downlink control channel may be based on the retuning time and the first bundling size.

The bundling module610may determine a first bundling size for an uplink data channel and a second bundling size for a downlink control channel based on the retuning time as described with reference toFIGS. 2-3. In some examples, determining the first bundling size includes reducing the first bundling size or the second bundling size from a nominal bundling size based on a the retuning time. In some examples, the first bundling size or the second bundling size may be based on whether the uplink data channel and the downlink control channel includes frequency resources of the same narrowband region. The bundling module610may also determine a bundling configuration for an uplink channel or a downlink channel. The bundling module610may also determine a bundling configuration for an uplink channel or a downlink channel. The bundling module610may also identify a downlink bundling configuration and an uplink bundling configuration for a UE.

The acknowledgement mode module615may determine an acknowledgement mode for the downlink transmission based on the grant as described with reference toFIGS. 2-3. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission and an indication of a bundling configuration for an acknowledgement message. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission, and where a bundling configuration for the acknowledgement message may be based on a bundling configuration for the grant. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission and an indication of resources for an acknowledgement message. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission, and resources for an acknowledgement message may be determined based on the grant and a bundling size. The acknowledgement mode module615may also determine an acknowledgement mode for a downlink transmission based on a channel condition. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission and a bundling configuration for an acknowledgement message.

In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission, and a bundling configuration for the acknowledgement message may be based on a bundling configuration for the grant. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission and an indication of resources for an acknowledgement message. In some examples, the grant includes an indication that the acknowledgement mode uses acknowledgement messages for the downlink transmission; resources for an acknowledgement message may be based on the grant and a bundling size.

The CFI module620may receive a first control format indicator as described with reference toFIGS. 2-3. The CFI module620may also receive a second control format indicator in a downlink grant, where the first control format indicator is received in system information or higher layer signaling, and where the communicating according to the first control format indicator is based on the second control format indicator. The CFI module620may also transmit a first CFI. The CFI module620may also transmit the second CFI in a downlink grant, and the first control format indicator may be transmitted in system information or higher layer signaling.

FIG. 7shows a diagram of a system700, including a UE that supports bundling and HARQ operation for enhanced machine-type communication in accordance with various aspects of the present disclosure. System700may include UE115-b, which may be an example of a wireless device400, a wireless device500, or a UE115described with reference toFIGS. 1, 2 and 4-6. UE115-bmay include a half-duplex timing module710, which may be an example of a half-duplex timing module410described with reference toFIGS. 4-6. UE115-bmay also include an MTC module725which may enable MTC operations such as half-duplex and narrowband communication. UE115-bmay also include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications.

UE115-bmay also include a processor705, and memory715(including software (SW)720), a transceiver735, and one or more antenna(s)740, each of which may communicate, directly or indirectly, with one another (e.g., via buses745). The transceiver735may communicate bi-directionally, via the antenna(s)740or wired or wireless links, with one or more networks, as described above. For example, the transceiver735may communicate bi-directionally with a base station105or another UE115. The transceiver735may include a modem to modulate the packets and provide the modulated packets to the antenna(s)740for transmission, and to demodulate packets received from the antenna(s)740. While UE115-bmay include a single antenna740, UE115-bmay also have multiple antennas740capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory715may include random access memory (RAM) and read only memory (ROM). The memory715may store computer-readable, computer-executable software/firmware code720including instructions that, when executed, cause the processor705to perform various functions described herein (e.g., bundling operation and hybrid automatic repeat request for enhanced machine-type communication, etc.). Alternatively, the software/firmware code720may not be directly executable by the processor705but cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor705may include an intelligent hardware device, (e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc.)

FIG. 8shows a diagram of a system800, including a base station105that supports bundling and HARQ operation for enhanced machine-type communication in accordance with various aspects of the present disclosure. System800may include base station105-c, which may be an example of a wireless device400, a wireless device500, or a base station105described with reference toFIGS. 1, 2 and 5-7. Base Station105-cmay include a base station half-duplex timing module810, which may be an example of a base station half-duplex timing module810described with reference toFIGS. 5-7. Base Station105-cmay also include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. For example, base station105-cmay communicate bi-directionally with UE115-cor UE115-d.

In some cases, base station105-cmay have one or more wired backhaul links. Base station105-cmay have a wired backhaul link (e.g., S1 interface, etc.) to the core network130. Base station105-cmay also communicate with other base stations105, such as base station105-dand base station105-evia inter-base station backhaul links (e.g., an X2 interface). Each of the base stations105may communicate with UEs115using the same or different wireless communications technologies. In some cases, base station105-cmay communicate with other base stations such as105-dor105-eutilizing base station communication module825. In some examples, base station communication module825may provide an X2 interface within a Long Term Evolution (LTE)/LTE-A wireless communication network technology to provide communication between some of the base stations105. In some examples, base station105-cmay communicate with other base stations through core network130. In some cases, base station105-cmay communicate with the core network130through network communications module830.

The base station105-cmay include a processor805, memory815(including software (SW)820), transceiver835, and antenna(s)840, which each may be in communication, directly or indirectly, with one another (e.g., over bus system845). The transceivers835may be configured to communicate bi-directionally, via the antenna(s)840, with the UEs115, which may be multi-mode devices. The transceiver835(or other components of the base station105-c) may also be configured to communicate bi-directionally, via the antennas840, with one or more other base stations (not shown). The transceiver835may include a modem configured to modulate the packets and provide the modulated packets to the antennas840for transmission, and to demodulate packets received from the antennas840. The base station105-cmay include multiple transceivers835, each with one or more associated antennas840. The transceiver may be an example of a combined receiver405and transmitter415ofFIG. 4.

The memory815may include RAM and ROM. The memory815may also store computer-readable, computer-executable software code820containing instructions that are configured to, when executed, cause the processor805to perform various functions described herein (e.g., bundling operation and hybrid automatic repeat request for enhanced machine-type communication, selecting coverage enhancement techniques, call processing, database management, message routing, etc.). Alternatively, the software820may not be directly executable by the processor805but be configured to cause the computer, e.g., when compiled and executed, to perform functions described herein. The processor805may include an intelligent hardware device, e.g., a CPU, a microcontroller, an ASIC, etc. The processor805may include various special purpose processors such as encoders, queue processing modules, base band processors, radio head controllers, digital signal processor (DSPs), and the like.

The base station communications module825may manage communications with other base stations105. In some cases, a communications management module may include a controller or scheduler for controlling communications with UEs115in cooperation with other base stations105. For example, the base station communications module825may coordinate scheduling for transmissions to UEs115for various interference mitigation techniques such as beamforming or joint transmission.

FIG. 9shows a flowchart illustrating a method900for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method900may be implemented by a UE115or its components as described with reference toFIGS. 1-8. For example, the operations of method900may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115may execute a set of codes to control the functional elements of the UE115to perform the functions described below. Additionally or alternatively, the UE115may perform aspects the functions described below using special-purpose hardware.

At block905, the UE115may receive a first grant for a first set of resources as described with reference toFIGS. 2-3. In certain examples, the operations of block905may be performed by the resource identification module505as described with reference toFIG. 5.

At block910, the UE115may receive a second grant for a second set of resources as described with reference toFIGS. 2-3. In certain examples, the operations of block910may be performed by the resource identification module505as described with reference toFIG. 5.

At block915, the UE115may determine that a portion of the first set of resources overlaps with a portion of the second set of resources as described with reference toFIGS. 2-3. In certain examples, the operations of block915may be performed by the overlap identification module510as described with reference toFIG. 5.

At block920, the UE115may communicate using the first set of resources or the second set of resources according to a prioritization between the first grant and the second grant as described with reference toFIGS. 2-3. In certain examples, the operations of block920may be performed by the communication module515as described with reference toFIG. 5.

FIG. 10shows a flowchart illustrating a method1000for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1000may be implemented by a UE115or its components as described with reference toFIGS. 1-8. For example, the operations of method1000may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115may execute a set of codes to control the functional elements of the UE115to perform the functions described below. Additionally or alternatively, the UE115may perform aspects the functions described below using special-purpose hardware. The method1000may also incorporate aspects of method900ofFIG. 9.

At block1005, the UE115may receive a first grant for a first set of resources as described with reference toFIGS. 2-3. In certain examples, the operations of block1005may be performed by the resource identification module505as described with reference toFIG. 5.

At block1010, the UE115may receive a second grant for a second set of resources as described with reference toFIGS. 2-3. In certain examples, the operations of block1010may be performed by the resource identification module505as described with reference toFIG. 5.

At block1015, the UE115may determine that a portion of the first set of resources overlaps with a portion of the second set of resources as described with reference toFIGS. 2-3. In certain examples, the operations of block1015may be performed by the overlap identification module510as described with reference toFIG. 5.

At block1020, the UE115may drop the first grant or the second grant based on a prioritization as described with reference toFIGS. 2-3. In certain examples, the operations of block1020may be performed by the resource identification module505as described with reference toFIG. 5.

At block1025, the UE115may communicate using the first set of resources or the second set of resources according to the prioritization between the first grant and the second grant as described with reference toFIGS. 2-3. In certain examples, the operations of block1025may be performed by the communication module515as described with reference toFIG. 5.

FIG. 11shows a flowchart illustrating a method1100for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1100may be implemented by a UE115or base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1100may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115or base station105may execute a set of codes to control the functional elements of the UE115or base station105to perform the functions described below. Additionally or alternatively, the UE115or base station105may perform aspects the functions described below using special-purpose hardware.

At block1105, the UE115or base station105may identify a retuning time for a UE to switch between a transmitting mode and a receiving mode based on a half-duplex communication capability of the UE as described with reference toFIGS. 2-3. In certain examples, the operations of block1105may be performed by the retuning module605as described with reference toFIG. 6.

At block1110, the UE115or base station105may determine a first bundling size for an uplink data channel and a second bundling size for a downlink control channel based on the retuning time as described with reference toFIGS. 2-3. In certain examples, the operations of block1110may be performed by the bundling module610as described with reference toFIG. 6.

At block1115, the UE115or base station105may communicate according to the retuning time and the first bundling size or the second bundling size as described with reference toFIGS. 2-3. In certain examples, the operations of block1115may be performed by the communication module515as described with reference toFIG. 5.

FIG. 12shows a flowchart illustrating a method1200for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1200may be implemented by a UE115or its components as described with reference toFIGS. 1-8. For example, the operations of method1200may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115may execute a set of codes to control the functional elements of the UE115to perform the functions described below. Additionally or alternatively, the UE115may perform aspects the functions described below using special-purpose hardware.

At block1205, the UE115may receive a grant for a downlink transmission as described with reference toFIGS. 2-3. In certain examples, the operations of block1205may be performed by the resource identification module505as described with reference toFIG. 5.

At block1210, the UE115may determine an acknowledgement mode for the downlink transmission based on the grant as described with reference toFIGS. 2-3. In certain examples, the operations of block1210may be performed by the acknowledgement mode module615as described with reference toFIG. 6.

FIG. 13shows a flowchart illustrating a method1300for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1300may be implemented by a base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1300may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a base station105may execute a set of codes to control the functional elements of the base station105to perform the functions described below. Additionally or alternatively, the base station105may perform aspects the functions described below using special-purpose hardware.

At block1305, the base station105may determine an acknowledgement mode for a downlink transmission based on a channel condition as described with reference toFIGS. 2-3. In certain examples, the operations of block1305may be performed by the acknowledgement mode module615as described with reference toFIG. 6.

At block1310, the base station105may transmit a grant to assign resources for the downlink transmission, where the grant includes an indication of the acknowledgement mode as described with reference toFIGS. 2-3. In certain examples, the operations of block1310may be performed by the resource identification module505as described with reference toFIG. 5.

FIG. 14shows a flowchart illustrating a method1400for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1400may be implemented by a UE115or its components as described with reference toFIGS. 1-8. For example, the operations of method1400may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115may execute a set of codes to control the functional elements of the UE115to perform the functions described below. Additionally or alternatively, the UE115may perform aspects the functions described below using special-purpose hardware.

At block1405, the UE115may determine a bundling configuration for an uplink channel or a downlink channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1405may be performed by the bundling module610as described with reference toFIG. 6.

At block1410, the UE115may receive a first control format indicator as described with reference toFIGS. 2-3. In certain examples, the operations of block1410may be performed by the CFI module620as described with reference toFIG. 6.

At block1415, the UE115may communicate according to the first control format indicator based on the bundling configuration for the uplink channel or the downlink channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1415may be performed by the communication module515as described with reference toFIG. 5.

FIG. 15shows a flowchart illustrating a method1500for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1500may be implemented by a base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1500may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a base station105may execute a set of codes to control the functional elements of the base station105to perform the functions described below. Additionally or alternatively, the base station105may perform aspects the functions described below using special-purpose hardware. The method1500may also incorporate aspects of method1400ofFIG. 14.

At block1505, the base station105may determine a bundling configuration for an uplink channel or a downlink channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1505may be performed by the bundling module610as described with reference toFIG. 6.

At block1510, the base station105may transmit a first control format indicator as described with reference toFIGS. 2-3. In certain examples, the operations of block1510may be performed by the CFI module620as described with reference toFIG. 6.

At block1515, the base station105may communicate according to the first control format indicator or a second control format indicator based on the bundling configuration for the uplink channel or the downlink channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1515may be performed by the communication module515as described with reference toFIG. 5.

FIG. 16shows a flowchart illustrating a method1600for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1600may be implemented by a UE115or base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1600may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115or base station105may execute a set of codes to control the functional elements of the UE115or base station105to perform the functions described below. Additionally or alternatively, the UE115or base station105may perform aspects the functions described below using special-purpose hardware.

At block1605, the UE115or base station105may identify a downlink bundling configuration and an uplink bundling configuration for a UE as described with reference toFIGS. 2-3. In certain examples, the operations of block1605may be performed by the bundling module610as described with reference toFIG. 6.

At block1610, the UE115or base station105may determine a resource configuration for uplink and downlink communications including a first set of resources associated with the downlink bundling configuration interleaved with a second set of resources associated with the uplink bundling configuration as described with reference toFIGS. 2-3. In certain examples, the operations of block1610may be performed by the resource identification module505as described with reference toFIG. 5.

At block1615, the UE115or base station105may communicate using the first set of resources or the second set of resources according to the resource configuration as described with reference toFIGS. 2-3. In certain examples, the operations of block1615may be performed by the communication module515as described with reference toFIG. 5.

FIG. 17shows a flowchart illustrating a method1700for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1700may be implemented by a UE115or base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1700may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115or base station105may execute a set of codes to control the functional elements of the UE115or base station105to perform the functions described below. Additionally or alternatively, the UE115or base station105may perform aspects the functions described below using special-purpose hardware.

At block1705, the UE115or base station105may communicate using a first set of bundled resources for an uplink data channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1705may be performed by the communication module515as described with reference toFIG. 5.

At block1710, the UE115or base station105may determine that a second set of bundled resources for a downlink control channel includes an uplink grant with a same HARQ process identifier as the uplink data channel, an uplink grant with a different HARQ process identifier than the uplink data channel, or a downlink grant as described with reference toFIGS. 2-3. In certain examples, the operations of block1710may be performed by the resource identification module505as described with reference toFIG. 5.

At block1715, the UE115or base station105may communicate using the second set of bundled resources based on the determination as described with reference toFIGS. 2-3. In certain examples, the operations of block1715may be performed by the communication module515as described with reference toFIG. 5.

FIG. 18shows a flowchart illustrating a method1800for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1800may be implemented by a UE115or base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1800may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115or base station105may execute a set of codes to control the functional elements of the UE115or base station105to perform the functions described below. Additionally or alternatively, the UE115or base station105may perform aspects the functions described below using special-purpose hardware. The method1800may also incorporate aspects of method1700ofFIG. 17.

At block1805, the UE115or base station105may communicate using a first set of bundled resources for an uplink data channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1805may be performed by the communication module515as described with reference toFIG. 5.

At block1810, the UE115or base station105may determine that a second set of bundled resources for a downlink control channel includes an uplink grant with a same HARQ process identifier as the uplink data channel, an uplink grant with a different HARQ process identifier than the uplink data channel, or a downlink grant based on a time difference between the first set of bundled resources and the second set of bundled resources as described with reference toFIGS. 2-3. In certain examples, the operations of block1810may be performed by the resource identification module505as described with reference toFIG. 5.

At block1815, the UE115or base station105may determine that a third set of bundled resources assigned by a grant in the second set of bundled resources overlaps in time with a fourth set of bundled resources for another downlink control channel, and may drop the grant in the second set of bundled resources as described with reference toFIGS. 2-3. In certain examples, the operations of block1815may be performed by the resource identification module505as described with reference toFIG. 5.

At block1820, the UE115or base station105may communicate using the second set of bundled resources based on the determinations as described with reference toFIGS. 2-3. In certain examples, the operations of block1820may be performed by the communication module515as described with reference toFIG. 5.

FIG. 19shows a flowchart illustrating a method1900for bundling or HARQ operation, or both, for enhanced machine-type communication in accordance with various aspects of the present disclosure. The operations of method1900may be implemented by a UE115or base station105or its components as described with reference toFIGS. 1-8. For example, the operations of method1900may be performed by the half-duplex timing module410as described with reference toFIGS. 4-7. In some examples, a UE115or base station105may execute a set of codes to control the functional elements of the UE115or base station105to perform the functions described below. Additionally or alternatively, the UE115or base station105may perform aspects the functions described below using special-purpose hardware.

At block1905, the UE115or base station105may communicate using a first set of bundled resources for an uplink control channel as described with reference toFIGS. 2-3. In certain examples, the operations of block1905may be performed by the communication module515as described with reference toFIG. 5.

At block1910, the UE115or base station105may determine that a second set of bundled resources for a downlink control channel includes an uplink grant or a downlink grant based on a time difference between the first set of bundled resources and the second set of bundled resources as described with reference toFIGS. 2-3. In certain examples, the operations of block1910may be performed by the resource identification module505as described with reference toFIG. 5.

At block1915, the UE115or base station105may communicate using the second set of bundled resources based on the determination as described with reference toFIGS. 2-3. In certain examples, the operations of block1915may be performed by the communication module515as described with reference toFIG. 5.

Thus, methods900,1000,1100,1200,1300,1400,1500,1600,1700,1800, and1900may provide for bundling or HARQ operation for enhanced machine-type communication. It should be noted that methods900,1000,1100,1200,1300,1400,1500,1600,1700,1800, and1900describe possible implementation, and that the operations and the steps may be rearranged or otherwise modified such that other implementations are possible. In some examples, aspects from two or more of the methods900,1000,1100,1200,1300,1400,1500,1600,1700,1800, and1900may be combined.

The description herein provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. Also, features described with respect to some examples may be combined in other examples.

The downlink transmissions described herein may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each communication link described herein—including, for example, wireless communications system100and200ofFIGS. 1 and 2—may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent on a different sub-carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc.