Techniques for reducing latency in a wireless communication system

Methods, systems, and devices are described for wireless communication. In one method, a first transmission may be transmitted on a contention-based channel, and a scheduling request for the first transmission may be transmitted on a scheduled channel. The scheduling request may be transmitted prior to determining that an acknowledgment (ACK) message has been received for the first transmission. In another method, a scheduling request for a first transmission may be received on a scheduled channel from a wireless device. Upon decoding a reception of the first transmission on a contention-based channel, transmission of a transmission grant to the wireless device may be withheld. Upon failing to decode the reception of the first transmission on the contention-based channel, the transmission grant may be transmitted to the wireless device.

BACKGROUND

Field of the Disclosure

The present disclosure, for example, relates to wireless communication systems, and more particularly to reducing the latency in a wireless communication system.

Description of Related Art

By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).

In some cases, a wireless multiple-access communication system may be used for mission critical transmissions. Mission critical transmissions may include, for example, high-reliability moderate latency (HRML) transmissions or high-reliability low latency (HRLL) transmissions. HRML transmissions may include transmissions for which the latency expectation is order of magnitudes higher than a transmission time interval (TTI; e.g., a symbol duration) of the system. Examples of HRML transmissions include health care remote monitoring/treatment applications, or real-time process automation applications. HRLL transmissions may include transmissions for which the latency expectation is comparable to a TTI (e.g., a symbol duration) of the system. Examples of HRLL transmissions include tactile internet applications, closed loop control applications, drone flying applications, or smart grid system protection applications.

SUMMARY

The present disclosure generally relates to wireless communication systems, and more particularly to improved systems, methods, and devices for reducing the latency of uplink transmissions in a wireless communication system. In a Long Term Evolution (LTE) or LTE-Advanced (LTE-A) communication systems, a user equipment (UE) may initiate an uplink transmission by transmitting a scheduling request to a base station. The base station may process the scheduling request and, upon allocating resources for the uplink transmission, transmit an uplink grant to the UE. In response to receiving the uplink grant, the UE may transmit the uplink transmission to the base station according to the uplink grant. Subsequently, the base station may transmit an acknowledgement (ACK) message or non-acknowledgement (NAK) message to the UE, indicating whether the uplink transmission was successfully received and decoded. Upon receiving an uplink grant with the NAK message, the UE may retransmit the first transmission. A scheduling request delay is therefore incurred when a UE initiates an uplink transmission.

The present disclosure describes techniques in which a scheduling request delay may be eliminated, under some scenarios, by 1) transmitting a first transmission (e.g., a first uplink transmission) on a contention-based channel (e.g., a channel over which two or more devices may transmit in an unscheduled manner, possibly leading to transmission collisions), and 2) prior to determining that an acknowledgement (ACK) message has been received for the first transmission, transmitting a scheduling request for the first transmission on a scheduled channel. When a base station receives and decodes the first transmission, the base station may transmit an ACK message for the first transmission and ignore the scheduling request. Thus, a scheduling request delay may not be incurred, and the latency of the uplink transmission may be reduced, when the base station is able to decode a reception of the first transmission on the contention-based channel. When a base station receives the scheduling request, the base station may transmit a transmission grant (e.g., an uplink grant) to the UE, thus incurring a scheduling request delay.

In a first set of illustrative examples, a method for wireless communication is described. In one configuration, the method includes transmitting a first transmission on a contention-based channel, and transmitting a scheduling request for the first transmission on a scheduled channel. The scheduling request may be transmitted prior to determining that an ACK message has been received for the first transmission.

In some examples of the method, the first transmission and the scheduling request for the first transmission may be transmitted simultaneously. In some examples, the method may include receiving an ACK message for the first transmission subsequent to transmitting the scheduling request. In some examples, the method may include receiving a transmission grant in response to transmitting the scheduling request, and retransmitting the first transmission on the scheduled channel according to the transmission grant.

In some examples, the method may include repeating transmission of the first transmission on the contention-based channel following expiration of a wait time, and repeating transmission of the scheduling request for the first transmission on the scheduled channel in accordance with at least one of: contemporaneously with repeating transmission of the first transmission or a scheduling request transmission periodicity. In some examples, transmitting the first transmission on the contention-based channel and repeating transmission of the first transmission on the contention-based channel may be performed using different transmission parameters. In some examples, the wait time may commence based at least in part on one of: transmitting the first transmission or transmitting the scheduling request. In some examples, the expiration of the wait time may occur prior to receiving at least one of: an ACK message for the first transmission or a transmission grant.

In some examples, the method may include transmitting as part of the first transmission, on the contention-based channel, a request for transmission of a second transmission; receiving an ACK message for the first transmission; receiving a transmission grant in response to transmitting the request for transmission of the second transmission; and transmitting the second transmission on the scheduled channel according to the transmission grant. In some examples of the method, the scheduled channel may be a narrow-band channel. In some examples of the method, the first transmission on the contention-based channel may include at least one of: an orthogonal frequency division multiple access (OFDMA) transmission, a code division multiple access (CDMA) transmission, or a spatial division multiple access (SDMA) transmission. In some examples of the method, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In some examples of the method, the contention-based channel may not overlap, in time or frequency, a channel available for scheduled transmissions.

In a second set of illustrative examples, an apparatus for wireless communication is described. In one configuration, the apparatus may include means for transmitting a first transmission on a contention-based channel, and means for transmitting a scheduling request for the first transmission on a scheduled channel. The scheduling request may be transmitted prior to determining that an ACK message has been received for the first transmission. In some examples, the apparatus may further include means for implementing one or more aspects of the method for wireless communication described above with respect to the first set of illustrative examples.

In a third set of illustrative examples, another apparatus for wireless communication is described. In one configuration, the apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to transmit a first transmission on a contention-based channel, and to transmit a scheduling request for the first transmission on a scheduled channel. The scheduling request may be transmitted prior to determining that an ACK message has been received for the first transmission. In some examples, the instructions may also be executable by the processor to implement one or more aspects of the method for wireless communication described above with respect to the first set of illustrative examples.

In a fourth set of illustrative examples, a non-transitory computer-readable medium storing computer-executable code for wireless communication is described. In one configuration, the code may be executable by a processor to transmit a first transmission on a contention-based channel, and to transmit a scheduling request for the first transmission on a scheduled channel. The scheduling request may be transmitted prior to determining that an ACK message has been received for the first transmission. In some examples, the code may also be executable by the processor to implement one or more aspects of the method for wireless communication described above with respect to the first set of illustrative examples.

In a fifth set of illustrative examples, another method for wireless communication is described. In one configuration, the method may include receiving on a scheduled channel, from a wireless device, a scheduling request for a first transmission; withholding transmission of a transmission grant to the wireless device upon decoding a reception of the first transmission on a contention-based channel; and transmitting the transmission grant to the wireless device upon failing to decode the reception of the first transmission on the contention-based channel.

In some examples of the method, the reception of the first transmission may be decoded during a second attempt to decode the first transmission, and the method may further include withholding transmission of the transmission grant to the wireless device after failing a first attempt to decode the first transmission. In some examples of the method, the transmission grant may be transmitted to the wireless device upon failing to decode the reception of the first transmission during a second attempt to decode the first transmission, and the method may further include withholding transmission of the transmission grant to the wireless device after failing a first attempt to decode the first transmission.

In some examples, the method may include transmitting an ACK message for the first transmission upon decoding the reception of the first transmission on the contention-based channel. In some examples, the method may include receiving a retransmission of the first transmission, on the scheduled channel, according to the transmission grant.

In a sixth set of illustrative examples, an apparatus for wireless communication is described. In one configuration, the apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to receive on a scheduled channel, from a wireless device, a scheduling request for a first transmission, to withhold transmission of a transmission grant to the wireless device upon decoding a reception of the first transmission on a contention-based channel, and to transmit the transmission grant to the wireless device upon failing to decode the reception of the first transmission on the contention-based channel. In some examples, the instructions may also be executable by the processor to implement one or more aspects of the method for wireless communication described above with respect to the fifth set of illustrative examples.

In a seventh set of illustrative examples, another method for wireless communication is described. In one configuration, the method may include receiving on a contention-based channel, from a wireless device, a first transmission, the first transmission including a request for transmission of a second transmission. The method may also include transmitting, to the wireless device, an ACK message for the first transmission, and a transmission grant for transmission of the second transmission on a scheduled channel.

In an eighth set of illustrative examples, an apparatus for wireless communication is described. In one configuration, the apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to receive on a contention-based channel, from a wireless device, a first transmission, the first transmission including a request for transmission of a second transmission, and to transmit, to the wireless device, an ACK message for the first transmission and a transmission grant for transmission of the second transmission on a scheduled channel. In some examples, the instructions may also be executable by the processor to implement one or more aspects of the method for wireless communication described above with respect to the seventh set of illustrative examples.

DETAILED DESCRIPTION

The described features generally relate to improved systems, methods, or devices for low latency communication in a wireless communication system. More particularly, and to avoid the delay introduced by a scheduling request during certain types of transmissions (e.g., hybrid automatic repeat request (HARQ)-based uplink transmissions), a transmission (e.g., from a user equipment (UE) to a base station) may be made on a contention-based channel. However, because there is a chance (e.g., an x % probability) that the transmission will collide with another transmission on the contention-based channel, thus requiring a retransmission, increasing latency, and decreasing reliability, a scheduling request for the transmission may be made, and sometimes simultaneously made, on a scheduled channel. When the transmission is received and decoded (e.g., by a base station), the scheduling request may be ignored and does not add a scheduling request delay to the transmission. When the transmission is not received or not decoded (e.g., because of a collision on the contention-based channel, or for other reasons), a transmission grant may be provided for retransmission of the transmission on the scheduled channel. Thus, the latency of the transmission may be decreased under some scenarios, and in a worst case scenario is no greater than the latency would have been without implementing one or more of the techniques described herein.

FIG. 1illustrates an example of a wireless communication system100in accordance with various aspects of the present disclosure. The wireless communication system100may include one or more base stations105, one or more UEs115, and a core network130. The core network130may provide user authentication, access authorization, tracking, internet protocol (IP) connectivity, and other access, routing, or mobility functions. The base stations105may interface with the core network130through backhaul links132(e.g., S1, etc.). The base stations105may perform radio configuration and scheduling for communication with the UEs115, or may operate under the control of a base station controller (not shown). In various examples, the base stations105may communicate, either directly or indirectly (e.g., through core network130), with one another over backhaul links134(e.g., X1, etc.), which may be wired or wireless communication links.

In some examples, the wireless communication system100may be or include a Long Term Evolution (LTE) or LTE-Advanced (LTE-A) network. In LTE/LTE-A networks, the term evolved node B (eNB) may be generally used to describe the base stations105, while the term UE may be generally used to describe the UEs115. The wireless communication system100may be a heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographical regions. For example, each eNB or base station105may provide communication coverage for a macro cell, a small cell, or other types of cell. The term “cell” is a 3GPP term that can be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context.

A macro cell may generally cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs115with service subscriptions with the network provider. A small cell may include a lower-powered base station, as compared with a macro cell, that may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs115with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs115having an association with the femto cell (e.g., UEs115in a closed subscriber group (CSG), UEs115for users in the home, and the like). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells (e.g., component carriers).

The communication networks that may accommodate some of the various disclosed examples may be packet-based networks that operate according to a layered protocol stack and data in the user plane may be based on the IP. A radio link control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A medium access control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use HARQ to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE115and the base stations105. The RRC protocol layer may also be used for core network130support of radio bearers for the user plane data. At the physical (PHY) layer, the transport channels may be mapped to physical channels.

The use of HARQ may help ensure that data is received correctly over a wireless 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 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 may not be added to each transmission, but may be retransmitted after the transmitter of the original message receives a NAK message indicating a failed attempt to decode a transmission.

The wireless communication links125shown in wireless communication system100may carry UL transmissions from a UE115to a base station105, or downlink (DL) transmissions, from a base station105to a UE115. The downlink transmissions may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each wireless communication link125may 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) modulated according to the various radio technologies described above. 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. The communication links125may transmit bidirectional communications 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 may be defined for FDD (e.g., frame structure type 1) and TDD (e.g., frame structure type 2).

In some embodiments of the wireless communication system100, base stations105or UEs115may include multiple antennas for employing antenna diversity schemes to improve communication quality and reliability between base stations105and UEs115. Additionally or alternatively, base stations105or UEs115may employ multiple input multiple output (MIMO) techniques that may take advantage of multi-path environments to transmit multiple spatial layers carrying the same or different coded data.

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). Time resources may be organized according to radio frames of length of 10 ms (Tf=307200·Ts), 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 transmission time interval (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).

FIG. 2shows an exemplary timeline200of a round trip communication between a UE and an application server, in accordance with various aspects of the present disclosure. In some examples, the round trip communication may be initiated by one of the UEs115described with reference toFIG. 1. The communication may begin with an input205being received or applied to a UE. By way of example, the input205may include a sensor reading, a photo, a video frame, or user input (e.g., a keyboard entry or touchscreen selection). The input205may be processed at an application layer210. The application layer210may, in turn, invoke an air interface215to make an uplink transmission to an application server. In some examples, the application server may be an entity within the cloud225.

The air interface215may include an interface between the UE and a base station (e.g., one of the base stations105described with reference toFIG. 1). By way of example, the air interface215is shown inFIG. 2to include a transmit portion and a receive portion. The transmit portion (e.g., at the UE) may include an upper layer230, transmission baseband (Tx BB) resources235, and a PHY layer frame240through which the uplink transmission may be processed. Similarly, the receive portion (e.g., at the base station) may include a PHY layer frame245, reception baseband (Rx BB) resources250, and an upper layer255through which the uplink transmission may be processed. After receiving and decoding the uplink transmission at the base station, the base station may forward the uplink transmission to a core network (e.g., part or all of the cloud225) over a backhaul link220. The backhaul link220may be an example of one of the backhaul links132described with reference toFIG. 1, and the core network may be an example of the core network130described with reference toFIG. 1. Upon receiving the uplink transmission, an application server or other entity within the cloud225may generate a response (e.g., a response to the input205). The response may then be forwarded back to the base station over the backhaul link220, for transmission to the UE in a downlink transmission over the air interface215. The application layer210may then apply the response at the UE.

In the case of some round trip communications, such as high-reliability moderate latency (HRML) and high-reliability low latency (HRLL) communications, it may be desirable to reduce the end-to-end latency of the round trip communication. It may also be desirable to reduce the end-to-end latency of round trip communications between the UE and the base station. The present disclosure therefore describes techniques for reducing latency in the air interface215, and more particularly, techniques for reducing latency in the air interface215when transmitting an uplink transmission from the UE to the cloud225.

As previously discussed, a UE operating in an LTE/LTE-A communication system may initiate an uplink transmission (e.g., a HARQ-based uplink transmission) by transmitting a scheduling request to a base station. The base station may process the scheduling request and, upon allocating resources for the uplink transmission, transmit an uplink grant to the UE. In response to receiving the uplink grant, the UE may transmit the uplink transmission to the base station according to the uplink grant. Subsequently, the base station may transmit an acknowledgement (ACK) message or non-acknowledgement (NAK) message to the UE, indicating whether the uplink transmission was successfully received and decoded. Upon receiving an uplink grant with the NAK message, the UE may retransmit the first transmission. A scheduling request delay is therefore incurred when a UE initiates an uplink transmission. One way to reduce latency in the air interface215is to eliminate the scheduling request delay. Techniques for eliminating the scheduling request delay under at least some scenarios are described in the present disclosure.

FIG. 3shows an exemplary timeline300of a HARQ-based uplink transmission, from a UE to a base station, in accordance with various aspects of the present disclosure. In some examples, the UE may be one of the UEs115described with reference toFIG. 1, and the base station may be one of the base stations105described with reference toFIG. 1. In some examples, the UE and base station may communicate using an air interface such as the air interface215described with reference toFIG. 2.

The timeline300includes a base station scheduling/processing timeline305and a UE scheduling request/processing timeline310. Each of the base station scheduling/processing timeline305and the UE scheduling request/processing timeline310may be divided into a plurality of transmission time intervals (TTIs) over an air interface. In some examples, the TTIs may correspond to subframes of a radio frame (e.g., subframes of an LTE/LTE-A radio frame). In other examples, the TTIs may correspond to symbols of one or more subframes of a radio frame. In other examples, some of the TTIs may have durations that differ from the durations of other TTIs.

By way of example, the UE may transmit a scheduling request320during a first TTI325. The base station may receive and process the scheduling request320during a second TTI330following the first TTI325. The base station may transmit an uplink grant (UL Grant)370to the UE during a third TTI335following the second TTI330. The UE may receive and decode the uplink grant370during a fourth TTI340following the third TTI335. The UE may transmit a first uplink transmission (UL Tx)375during a fifth TTI345following the fourth TTI340. The base station may receive and process the first uplink transmission375during a sixth TTI350following the fifth TTI345. The base station may transmit an ACK message or NAK message (ACK/NAK)380, and when necessary, an additional uplink grant, to the UE during a seventh TTI355following the sixth TTI350. The UE may receive and decode the ACK message or NAK message, and optionally the additional uplink grant, during an eighth TTI360following the seventh TTI355. When the UE receives an ACK message during the eighth TTI360, the UE may transmit a second uplink transmission to the base station during a ninth TTI365following the eighth TTI360. When the UE receives a NAK message during the eighth TTI360, the UE may retransmit the first transmission to the base station during the ninth TTI365. The base station may receive and process the second uplink transmission or retransmission of the first uplink transmission during a tenth TTI385following the ninth TTI365. The UE and base station may continue in such a manner until the UE has completed its uplink transmissions, or until an uplink transmission period has expired.

Under a best case scenario, the HARQ-based uplink transmission described with reference toFIG. 3is associated with a six TTI delay (e.g., from transmission of the scheduling request by the UE to receipt of the first uplink transmission by the base station). Under a best case one retransmission scenario, the HARQ-based uplink transmission described with reference toFIG. 3is associated with a ten TTI delay. Under scenarios in which the first uplink transmission spans more than one TTI, these delays could be longer.

Under any scenario, the HARQ-based uplink transmission described with reference toFIG. 3is associated with a scheduling request delay (i.e., the delay before transmitting the first uplink transmission) of four TTIs.FIGS. 4-21describe techniques, including systems, methods, and devices, for eliminating the scheduling request delay under some scenarios. With reference to the exemplary timeline300described with reference toFIG. 3, this reduces the delay before the base station receives the first transmission of the UE to one TTI.

FIGS. 4-9describe various scenarios in which a scheduling request delay may (FIGS. 4, 7, and 8) or may not (FIGS. 5, 6, and 9) be eliminated prior to transmitting a first transmission. In some examples, the techniques described with reference to the various scenarios may be applied to HMRL or HRLL transmissions. In some examples, the techniques may be applied to uplink transmissions. In some examples, the techniques may be applied to HARQ-based transmissions. In some examples, the techniques may be applied to LTE/LTE-A transmissions. The techniques may also or alternatively be applied to other types of transmissions.

FIG. 4shows a communication flow400between a UE115-aand a base station105-a, in accordance with various aspects of the present disclosure. The UE115-amay be an example of aspects of one or more of the UEs115described with reference toFIG. 1. The base station105-amay be an example of aspects of one or more of the base stations105described with reference toFIG. 1.

The communication flow400may begin with the UE115-atransmitting a first transmission405, and a scheduling request410for the first transmission, to the base station105-a. The first transmission405may be transmitted on a contention-based channel.

The scheduling request410may be transmitted on a scheduled channel. The scheduling request410may be transmitted before, after, or simultaneously with the first transmission405, but prior to determining that an ACK message has been received for the first transmission405. In some configurations, the scheduled channel may be a narrow-band channel (e.g., a channel having a payload that is substantially smaller than the payload of the first transmission405, regardless of the physical bandwidth of the narrow-band channel (which physical bandwidth may be narrow or wide)).

At block415, the base station105-amay receive and decode the first transmission405. Upon receiving and decoding the first transmission405, the scheduling request410for the first transmission is rendered moot and may be ignored by the base station105-a.

At block420, the base station105-amay determine that the first transmission405did not include a request for transmission of a second transmission (e.g., that the first transmission405did not include a scheduling request).

In response to receiving and decoding the first transmission405, and determining that the first transmission405did not include a request for transmission of a second transmission, the base station105-amay transmit an acknowledgement (ACK) message425to the UE115-a. Subsequent to transmission of the ACK message425, the communication flow400may end or continue with the performance of other operations by the UE115-aor base station105-a.

FIG. 5shows a communication flow500between a UE115-band a base station105-b, in accordance with various aspects of the present disclosure. The UE115-bmay be an example of aspects of one or more of the UEs115described with reference toFIG. 1 or 4. The base station105-bmay be an example of aspects of one or more of the base stations105described with reference toFIG. 1 or 4.

The communication flow500may begin with the UE115-btransmitting a first transmission505, and a scheduling request510for the first transmission, to the base station105-b. The first transmission505may be transmitted on a contention-based channel.

The scheduling request510may be transmitted on a scheduled channel. The scheduling request510may be transmitted before, after, or simultaneously with the first transmission505, but prior to determining that an ACK message has been received for the first transmission505. In some configurations, the scheduled channel may be a narrow-band channel (e.g., a channel having a payload that is substantially smaller than the payload of the first transmission505, regardless of the physical bandwidth of the narrow-band channel (which physical bandwidth may be narrow or wide)).

At block515, the base station105-bmay not receive, or receive and be unable to decode, the first transmission505. However, the base station105-bmay receive and decode the scheduling request510for the first transmission.

In response to receiving and decoding the scheduling request510, the base station105-bmay transmit a transmission grant (e.g., an uplink grant)520to the UE115-b. The transmission grant520may allocate resources for retransmitting the first transmission on the scheduled channel.

At block525, the UE115-bmay receive and decode the transmission grant520. The UE115-bmay then retransmit the first transmission on the scheduled channel, according to the transmission grant (e.g., as retransmission530). Subsequent to the retransmission530, the communication flow500may end or continue with the performance of other operations (e.g., HARQ operations) by the UE115-bor base station105-b.

FIG. 6shows a communication flow600between a UE115-cand a base station105-c, in accordance with various aspects of the present disclosure. The UE115-cmay be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, or5. The base station105-cmay be an example of aspects of one or more of the base stations105described with reference toFIG. 1, 4, or5.

The communication flow600may begin with the UE115-ctransmitting a first transmission605, and a scheduling request610for the first transmission, to the base station105-c. The first transmission605may be transmitted on a contention-based channel.

The scheduling request610may be transmitted on a scheduled channel. The scheduling request610may be transmitted before, after, or simultaneously with the first transmission605, but prior to determining that an ACK message has been received for the first transmission605. In some configurations, the scheduled channel may be a narrow-band channel (e.g., a channel having a payload that is substantially smaller than the payload of the first transmission605, regardless of the physical bandwidth of the narrow-band channel (which physical bandwidth may be narrow or wide)).

At block615, the base station105-cmay fail to receive, or receive and be unable to decode, the first transmission605. The base station105-cmay also fail to receive, or receive and be unable to decode, the scheduling request610for the first transmission. As a result, the base station105-cmay not transmit, to the UE115-c, an ACK message for the first transmission or a transmission grant for the first transmission.

At block620, the UE115-cmay determine that a wait time has expired prior to receiving at least one of an ACK message for the first transmission or a transmission grant for the first transmission. In some embodiments, the wait time may commence based at least in part on transmitting the first transmission605or transmitting the scheduling request610.

In response to expiration of the wait time, the UE115-cmay retransmit the first transmission605on the contention-based channel (e.g., as retransmission625) and retransmit the scheduling request610on the scheduled channel (e.g., as retransmission630). In some instances, the scheduling request may be retransmitted on the scheduled channel contemporaneously with repeating transmission of the first transmission. In other instances, the scheduling request may be retransmitted in accordance with a scheduling request transmission periodicity. In some cases, the UE115-cmay select different transmission parameters for retransmitting the first transmission or the scheduling request. Subsequent to transmitting the retransmissions625and630, the communication flow600may end or continue with the performance of other operations by the UE115-cor base station105-c.

FIG. 7shows a communication flow700between a UE115-dand a base station105-d, in accordance with various aspects of the present disclosure. The UE115-dmay be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, or6. The base station105-dmay be an example of aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, or6.

The communication flow700may begin with the UE115-dtransmitting a first transmission705, and a scheduling request710for the first transmission, to the base station105-d. The first transmission705may be transmitted on a contention-based channel.

The scheduling request710may be transmitted on a scheduled channel. The scheduling request710may be transmitted before, after, or simultaneously with the first transmission705, but prior to determining that an ACK message has been received for the first transmission705. In some configurations, the scheduled channel may be a narrow-band contention-free channel (e.g., a channel having a payload that is substantially smaller than the payload of the first transmission705, regardless of the physical bandwidth of the narrow-band channel (which physical bandwidth may be narrow or wide)).

At block715, the base station105-dmay receive and decode the first transmission705. Upon receiving and decoding the first transmission705, the scheduling request710for the first transmission is rendered moot and may be ignored by the base station105-d.

At block720, the base station105-dmay determine that a request for transmission of a second transmission (e.g., a scheduling request) was transmitted as part of the first transmission705(e.g., transmitted in a MAC header of the first transmission705).

In response to receiving and decoding the first transmission705, and determining that the first transmission705includes a request for transmission of a second transmission, the base station105-dmay transmit an acknowledgement (ACK) message725, and a transmission grant730for the second transmission, to the UE115-d.

At block735, the UE115-dmay receive and decode the transmission grant730. The UE115-dmay then transmit the second transmission740on the scheduled channel, according to the transmission grant. Subsequent to transmitting the second transmission740, the communication flow700may end or continue with the performance of other operations (e.g., HARQ operations) by the UE115-dor base station105-d.

FIG. 8shows a communication flow800between a UE115-eand a base station105-e, in accordance with various aspects of the present disclosure. The UE115-emay be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, or7. The base station105-emay be an example of aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, or7.

The communication flow800may begin with the UE115-etransmitting a first transmission805, and a scheduling request810for the first transmission, to the base station105-e. The first transmission805may be transmitted on a contention-based channel.

The scheduling request810may be transmitted on a scheduled channel. The scheduling request810may be transmitted before, after, or simultaneously with the first transmission805, but prior to determining that an ACK message has been received for the first transmission805. In some configurations, the scheduled channel may be a narrow-band channel (e.g., a channel having a payload that is substantially smaller than the payload of the first transmission805, regardless of the physical bandwidth of the narrow-band channel (which physical bandwidth may be narrow or wide)).

At block815, the base station105-emay fail to receive, or receive and be unable to decode, the first transmission805. However, the base station105-emay receive and decode the scheduling request810for the first transmission.

At block820, the base station105-emay withhold transmission of a transmission grant to the UE115-ewhile the base station105-emakes another attempt to decode the first transmission805. In some cases, information obtained from the scheduling request810may assist the base station105-ein decoding the first transmission805.

At block825, it may be determined that the further attempt to decode the first transmission805succeeded, in which case the base station105-emay withhold transmission of the transmission grant and transmit an acknowledgement (ACK) message830to the UE115-e. When the first transmission805includes a request for transmission of a second transmission (e.g., a scheduling request), the base station105-emay also transmit a transmission grant for the second transmission to the UE115-e. Subsequent to transmission of the ACK message830, the communication flow800may end or continue with the performance of other operations by the UE115-eor base station105-e.

FIG. 9shows a communication flow900between a UE115-fand a base station105-f, in accordance with various aspects of the present disclosure. The UE115-fmay be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, or8. The base station105-fmay be an example of aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, or8.

The communication flow900may begin with the UE115-ftransmitting a first transmission905, and a scheduling request910for the first transmission, to the base station105-f. The first transmission905may be transmitted on a contention-based channel.

The scheduling request910may be transmitted on a scheduled channel. The scheduling request910may be transmitted before, after, or simultaneously with the first transmission905, but prior to determining that an ACK message has been received for the first transmission905. In some configurations, the scheduled channel may be a narrow-band channel (e.g., a channel having a payload that is substantially smaller than the payload of the first transmission905, regardless of the physical bandwidth of the narrow-band channel (which physical bandwidth may be narrow or wide)).

At block915, the base station105-fmay fail to receive, or receive and be unable to decode, the first transmission905. However, the base station105-fmay receive and decode the scheduling request910for the first transmission.

At block920, the base station105-fmay withhold transmission of a transmission grant to the UE115-fwhile the base station105-fmakes another attempt to decode the first transmission905. In some cases, information obtained from the scheduling request910may assist the base station105-fin decoding the first transmission905.

At block925, it may be determined that the further attempt to decode the first transmission905failed, in which case the base station105-fmay transmit a transmission grant (e.g., an uplink grant)930to the UE115-f. The transmission grant930may allocate resources for retransmitting the first transmission on the scheduled channel.

At block935, the UE115-fmay receive and decode the transmission grant930. The UE115-fmay then retransmit the first transmission on the scheduled channel, according to the transmission grant (e.g., as retransmission940). Subsequent to the retransmission940, the communication flow900may end or continue with the performance of other operations (e.g., HARQ operations) by the UE115-for base station105-f.

In some embodiments of the communication flow described with reference toFIG. 4, 5, 6, 7, 8, or9, the first transmission may be transmitted as an OFDMA transmission, a CDMA transmission, or a spatial division multiple access (SDMA) transmission. An OFDMA transmission may be useful when transmitting a large payload with light loading. A CDMA transmission may be useful when transmitting a small payload, and may enable a multiplexing of parallel transmissions. In some embodiments, the first transmission may be transmitted as a CDMA transmission, and a retransmission of the first transmission, when transmitted, may be transmitted as an OFDMA transmission.

In some embodiments of the communications flow described with reference toFIG. 4, 5, 6, 7, 8, or9, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. When the contention-based channel is only used for HRLL transmissions, the HRLL transmissions may occur at a relative low duty cycle, and thus, the channel may be available for scheduled transmissions much of the time. Resources may be selected or allocated for the contention-based channel such that the likelihood of a transmission on the contention-based resources being received and decoded by a base station is increased. Power control and rate control (e.g., a low rate modulation and coding scheme (MCS) may also, or alternatively, be used to increase the chance that a transmission on the contention-based channel will be received and decoded by a base station. In some cases, resources with a low rise over thermal (ROT) may be prioritized for the contention-based channel. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions.

In some embodiments of the communication flow described with reference toFIG. 5, 7, or9, an indication may be used to identify a need for the retransmission of the first transmission, so that the retransmission of the first transmission (which first transmission was initially transmitted on a contention-based channel) does not collide with a regularly-scheduled transmission or retransmission on a scheduled channel. In some cases, the indication may cause the regularly-scheduled transmission or retransmission to be suspended in favor or first retransmitting the first transmission (e.g., because the first transmission may be an HRML or HRLL transmission and the regularly-scheduled transmission may be assumed to be of less importance). In other cases, the indication may cause a UE to multiplex the retransmission of the first transmission with regularly-scheduled transmissions or retransmissions.

FIG. 10shows a block diagram1000of a device1015for use in wireless communication, in accordance with various aspects of the present disclosure. The device1015may be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, or9. The device1015may also be or include a processor. The device1015may include a receiver module1010, a wireless communication management module1020, or a transmitter module1030. Each of these modules may be in communication with each other.

In some examples, the receiver module1010may include at least one radio frequency (RF) receiver. The receiver module1010or RF receiver may be used to receive various types of data or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links of the wireless communication system100described with reference toFIG. 1.

In some examples, the transmitter module1030may include at least one RF transmitter. The transmitter module1030or RF transmitter may be used to transmit various types of data or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links of the wireless communication system100described with reference toFIG. 1.

In some configurations, the communication links over which the receiver module1010or transmitter module1030receive/transmit transmissions may carry one or more contention-based channels or scheduled channels, such as the contention-based channels or scheduled channels described with reference toFIG. 4, 5, 6, 7, 8, or9.

The wireless communication management module1020may be used to manage one or more aspects of wireless communication for the device1015. In some examples, the wireless communication management module1020may include a contention-based transmission management module1035or a scheduled transmission management module1040.

The contention-based transmission management module1035may be used to transmit a first transmission, via the transmitter module1030, on a contention-based channel. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions.

The scheduled transmission management module1040may be used to transmit a scheduling request for the first transmission on a scheduled channel. The scheduling request may also be transmitted via the transmitter module1030. The scheduled transmission management module1040may transmit the scheduling request prior to determining that an ACK message has been received for the first transmission. In some configurations, the scheduled channel may be a narrow-band channel.

In some embodiments of the wireless communication management module1020, the contention-based transmission management module1035and scheduled transmission management module1040may transmit the first transmission and scheduling request simultaneously.

FIG. 11shows a block diagram1100of a device1015-afor use in wireless communication, in accordance with various aspects of the present disclosure. The device1015-amay be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, or9, or aspects of the device1015described with reference toFIG. 10. The device1015-amay also be or include a processor. The device1015-amay include a receiver module1010, a wireless communication management module1020-a, or a transmitter module1030. Each of these modules may be in communication with each other.

In some embodiments, the receiver module1010or transmitter module1030may be configured as described with reference toFIG. 10.

The wireless communication management module1020-amay be used to manage one or more aspects of wireless communication for the device1015-a. In some examples, the wireless communication management module1020-amay include a contention-based transmission management module1035-a, a scheduled transmission management module1040-a, an ACK processing module1135, a transmission grant processing module1140, a transmission parameter selection module1145, or a wait time management module1150.

The contention-based transmission management module1035-amay be used to transmit a first transmission, via the transmitter module1030, on a contention-based channel. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions. When the size of a transmission to be made exceeds a maximum size of the first transmission, a request for transmission of a second transmission (e.g., a scheduling request) may be transmitted as part of the first transmission (e.g., a scheduling request for the second transmission may be transmitted in a MAC header of the first transmission).

The scheduled transmission management module1040may be used to transmit a scheduling request for the first transmission on a scheduled channel. The scheduling request may also be transmitted via the transmitter module1030. The scheduled transmission management module1040may transmit the scheduling request prior to determining that an ACK message has been received for the first transmission. In some configurations, the scheduled channel may be a narrow-band channel.

In some embodiments of the wireless communication management module1020, the contention-based transmission management module1035-aand scheduled transmission management module1040-amay transmit the first transmission and scheduling request simultaneously.

The ACK processing module1135may be used to determine whether an ACK message is received for the first transmission. In some configurations, the determination made by the ACK processing module1135may be made at a scheduled time, upon expiration of a timer, or repeatedly (e.g., repeatedly within a defined time period or repeatedly for a defined number of times).

The transmission grant processing module1140may be used to determine whether a transmission grant (e.g., an uplink grant) is received in response to transmitting the scheduling request. In some configurations, the determination made by the transmission grant processing module1140may be made at a scheduled time, upon expiration of a timer, or repeatedly (e.g., repeatedly within a defined time period or repeatedly for a defined number of times). When the transmission grant processing module1140determines that a transmission grant is received in response to transmitting the scheduling request, the scheduled transmission management module1040may be used to retransmit the first transmission according to the transmission grant.

The transmission grant processing module1140may also be used to determine whether a transmission grant (e.g., an uplink grant) is received in response to transmitting a request for transmission of a second transmission (e.g., a scheduling request). In some cases, an ACK message and the transmission grant may be received as part of a single transmission. When the transmission grant processing module1140determines that a transmission grant is received in response to transmitting a request for transmission of a second transmission, the scheduled transmission management module1040may be used to transmit the second transmission according to the transmission grant.

When the ACK processing module1135determines that an ACK message for the first transmission has not been received, and when the transmission grant processing module1140determines that a transmission grant for the first transmission has not been received, e.g., after expiration of a wait time, the contention-based transmission management module1035-aand scheduled transmission management module1040-amay be used, respectively, to retransmit the first transmission and the scheduling request. In some instances, the scheduling request may be retransmitted on the scheduled channel contemporaneously with repeating transmission of the first transmission. In other instances, the scheduling request may be retransmitted in accordance with a scheduling request transmission periodicity.

The wait time management module1150may be used to manage the wait time on which retransmission of the first transmission and scheduling request are based. In some examples, the wait time may commence based at least in part on transmitting the first transmission or transmitting the scheduling request.

FIG. 12shows a block diagram1200of a device1205for use in wireless communication, in accordance with various aspects of the present disclosure. The device1205may be an example of aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, 8, or9. The device1205may also be or include a processor. The device1205may include a receiver module1210, a wireless communication management module1220, or a transmitter module1230. Each of these modules may be in communication with each other.

In some examples, the receiver module1210may include at least one RF receiver. The receiver module1210or RF receiver may be used to receive various types of data or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links of the wireless communication system100described with reference toFIG. 1.

In some examples, the transmitter module1230may include at least one RF transmitter. The transmitter module1230or RF transmitter may be used to transmit various types of data or control signals (i.e., transmissions) over one or more communication links of a wireless communication system, such as one or more communication links of the wireless communication system100described with reference toFIG. 1.

In some configurations, the communication links over which the receiver module1210or transmitter module1230receive/transmit transmissions may carry one or more contention-based channels or scheduled channels, such as the contention-based channels or scheduled channels described with reference toFIG. 4, 5, 6, 7, 8, or9.

The wireless communication management module1220may be used to manage one or more aspects of wireless communication for the device1205. In some examples, the wireless communication management module1220may include a contention-based transmission reception management module1235, a scheduled transmission reception management module1240, an ACK management module1245, or a transmission grant management module1250.

The contention-based transmission reception management module1235may be used to receive a first transmission, on a contention-based channel, from a wireless device (e.g., a UE). In some cases, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission. In some cases, a request for transmission of a second transmission (e.g., a scheduling request) may be received as part of the first transmission (e.g., a scheduling request for the second transmission may be received in a MAC header of the first transmission). In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions.

The scheduled transmission reception management module1240may be used to receive a scheduling request for the first transmission, on a scheduled channel, from the wireless device. In some configurations, the scheduled channel may be a narrow-band channel whose payload is substantially smaller than the payload of the first transmission, regardless of the physical bandwidth of the narrow-band channel.

The contention-based transmission reception management module1235and scheduled transmission reception management module1240may, under some scenarios, receive the first transmission and the scheduling request simultaneously. In other scenarios, the contention-based transmission reception management module1235may fail to receive, or receive and fail to decode, the first transmission, but the scheduled transmission reception management module1240may receive the scheduling request. In other scenarios, the contention-based transmission reception management module1235may receive the first transmission, but the scheduled transmission reception management module1240may fail to receive the scheduling request.

Upon receiving the first transmission, the ACK management module1245may be used to transmit, to the wireless device, an ACK message for the first transmission.

Upon failing to receive, or to receive and decode, the first transmission, and upon receiving the scheduling request, the transmission grant management module1250may be used to transmit, to the wireless device, a transmission grant for transmission of the first transmission on the scheduled channel. Upon receiving the first transmission and determining the first transmission includes a request for transmission of a second transmission, the transmission grant management module1250may transmit, to the wireless device, a transmission grant for transmission of the second transmission on the scheduled channel.

FIG. 13shows a block diagram1300of a device1205-afor use in wireless communication, in accordance with various aspects of the present disclosure. The device1205-amay be an example of aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, or aspects of the device1205described with reference toFIG. 12. The device1205-amay also be or include a processor. The device1205-amay include a receiver module1210, a wireless communication management module1220-a, or a transmitter module1230. Each of these modules may be in communication with each other.

In some embodiments, the receiver module1210or transmitter module1230may be configured as described with reference toFIG. 12.

The wireless communication management module1220-amay be used to manage one or more aspects of wireless communication for the device1205-a. In some examples, the wireless communication management module1220-amay include a contention-based transmission reception management module1235-a, a scheduled transmission reception management module1240-a, an ACK management module1245-a, or a transmission grant management module1250-a.

The contention-based transmission reception management module1235-amay be used to receive a first transmission, on a contention-based channel, from a wireless device (e.g., a UE). In some cases, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission. In some cases, a request for transmission of a second transmission (e.g., a scheduling request) may be received as part of the first transmission (e.g., received in a MAC header of the first transmission). In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions.

In some embodiments, the contention-based transmission reception management module1235-amay include a decoding management module1335. The decoding management module1335may be used to decode (or attempt to decode) the first transmission.

The scheduled transmission reception management module1240-amay be used to receive a scheduling request for the first transmission, on a scheduled channel, from the wireless device. In some configurations, the scheduled channel may be a narrow-band channel.

The contention-based transmission reception management module1235-aand scheduled transmission reception management module1240-amay, under some scenarios, receive the first transmission and the scheduling request simultaneously. In other scenarios, the contention-based transmission reception management module1235-amay fail to receive, or receive and fail to decode, the first transmission, but the scheduled transmission reception management module1240-amay receive the scheduling request. In other scenarios, the contention-based transmission reception management module1235-amay receive the first transmission, but the scheduled transmission reception management module1240-amay fail to receive the scheduling request.

Upon decoding the first transmission, the ACK management module1245-amay be used to transmit, to the wireless device, an ACK message for the first transmission.

Upon failing to receive the first transmission, and upon receiving the scheduling request, the transmission grant management module1250-amay be used to transmit, to the wireless device, a transmission grant for transmission of the first transmission on the scheduled channel. Upon failing to decode the first transmission, and upon receiving the scheduling request, the transmission grant management module1250-amay cause the decoding management module1335to make an additional attempt to decode the first transmission. When the additional attempt to decode the first transmission is successful, the transmission grant management module1250-amay withhold transmission of (i.e., not transmit) a transmission grant for transmission of the first transmission on the scheduled channel, and cause the ACK management module1245-ato transmit, to the wireless device, an ACK message for the first transmission. When the additional attempt to decode the first transmission is not successful, the transmission grant management module1250-amay transmit, to the wireless device, a transmission grant for transmission of the first transmission on the scheduled channel. Upon decoding the first transmission and determining the first transmission includes a scheduling request for a second transmission, the transmission grant management module1250-amay transmit, to the wireless device, a transmission grant for transmission of the second transmission on the scheduled channel.

FIG. 14shows a block diagram1400of a UE115-gfor use in wireless communication, in accordance with various aspects of the present disclosure. The UE115-gmay have various configurations and may be included or be part of a personal computer (e.g., a laptop computer, a netbook computer, a tablet computer, etc.), a cellular telephone, a PDA, a digital video recorder (DVR), an internet appliance, a gaming console, an e-reader, etc. The UE115-gmay, in some examples, have an internal power supply (not shown), such as a small battery, to facilitate mobile operation. In some examples, the UE115-gmay be an example of aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, or9, or aspects of one or more of the devices1015described with reference toFIG. 10 or 11. The UE115-gmay be configured to implement at least some of the UE or device features and functions described with reference toFIG. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or11.

The UE115-gmay include a UE processor module1410, a UE memory module1420, at least one UE transceiver module (represented by UE transceiver module(s)1430), at least one UE antenna (represented by UE antenna(s)1440), or a UE wireless communication management module1020-b. Each of these components may be in communication with each other, directly or indirectly, over one or more buses1435.

The UE memory module1420may include random access memory (RAM) or read-only memory (ROM). The UE memory module1420may store computer-readable, computer-executable code1425containing instructions that are configured to, when executed, cause the UE processor module1410to perform various functions described herein related to wireless communication, including, for example, transmissions on one or more contention-based channels and one or more scheduled channels. Alternatively, the code1425may not be directly executable by the UE processor module1410but be configured to cause the UE115-g(e.g., when compiled and executed) to perform various of the functions described herein.

The UE processor module1410may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an ASIC, etc. The UE processor module1410may process information received through the UE transceiver module(s)1430or information to be sent to the UE transceiver module(s)1430for transmission through the UE antenna(s)1440. The UE processor module1410may handle, alone or in connection with the UE wireless communication management module1020-b, various aspects of communicating over (or managing communications over) a contention-based channel or a scheduled channel.

The UE transceiver module(s)1430may include a modem configured to modulate packets and provide the modulated packets to the UE antenna(s)1440for transmission, and to demodulate packets received from the UE antenna(s)1440. The UE transceiver module(s)1430may, in some examples, be implemented as one or more UE transmitter modules and one or more separate UE receiver modules. The UE transceiver module(s)1430may support communications on one or more contention-based channels or one or more scheduled channels. The UE transceiver module(s)1430may be configured to communicate bi-directionally, via the UE antenna(s)1440, with one or more of the base stations, such as one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, 8, or9, or one or more devices, such as one or more of the devices1015described with reference toFIG. 10 or 11. While the UE115-gmay include a single UE antenna, there may be examples in which the UE115-gmay include multiple UE antennas1440.

The UE wireless communication management module1020-bmay be configured to perform or control some or all of the UE115or device1015features or functions described with reference toFIG. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or11related to wireless communication over one or more contention-based channels or one or more scheduled channels. The UE wireless communication management module1020-b, or portions of it, may include a processor, or some or all of the functions of the UE wireless communication management module1020-bmay be performed by the UE processor module1410or in connection with the UE processor module1410. In some examples, the UE wireless communication management module1020-bmay be an example of the wireless communication management module1020described with reference toFIG. 10 or 11.

FIG. 15shows a block diagram1500of a base station105-g(e.g., a base station forming part or all of an eNB) for use in wireless communication, in accordance with various aspects of the present disclosure. In some examples, the base station105-gmay be an example of one or more aspects of the base station105described with reference toFIG. 1, 4, 5, 6, 7, 8, or9, or aspects of the device1205described with reference toFIG. 12 or 13. The base station105-gmay be configured to implement or facilitate at least some of the base station features and functions described with reference toFIG. 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, or13.

The base station105-gmay include a base station processor module1510, a base station memory module1520, at least one base station transceiver module (represented by base station transceiver module(s)1550), at least one base station antenna (represented by base station antenna(s)1555), or a base station wireless communication management module1220-b. The base station105-gmay also include one or more of a base station communications module1530or a network communications module1540. Each of these components may be in communication with each other, directly or indirectly, over one or more buses1535.

The base station memory module1520may include RAM or ROM. The base station memory module1520may store computer-readable, computer-executable code1525containing instructions that are configured to, when executed, cause the base station processor module1510to perform various functions described herein related to wireless communication, including, for example, receptions of transmissions on one or more contention-based channels and one or more scheduled channels. Alternatively, the code1525may not be directly executable by the base station processor module1510but be configured to cause the base station105-g(e.g., when compiled and executed) to perform various of the functions described herein.

The base station processor module1510may include an intelligent hardware device, e.g., a CPU, a microcontroller, an ASIC, etc. The base station processor module1510may process information received through the base station transceiver module(s)1550, the base station communications module1530, or the network communications module1540. The base station processor module1510may also process information to be sent to the transceiver module(s)1550for transmission through the base station antenna(s)1555, to the base station communications module1530, for transmission to one or more other base stations105-hand105-i, or to the network communications module1540for transmission to a core network1545, which may be an example of one or more aspects of the core network130described with reference toFIG. 1. The base station processor module1510may handle, alone or in connection with the base station wireless communication management module1220-b, various aspects of communicating over (or managing communications over) a contention-based channel or a scheduled channel.

The base station transceiver module(s)1550may include a modem configured to modulate packets and provide the modulated packets to the base station antenna(s)1555for transmission, and to demodulate packets received from the base station antenna(s)1555. The base station transceiver module(s)1550may, in some examples, be implemented as one or more base station transmitter modules and one or more separate base station receiver modules. The base station transceiver module(s)1550may support communications on one or more contention-based channels or one or more scheduled channels. The base station transceiver module(s)1550may be configured to communicate bi-directionally, via the base station antenna(s)1555, with one or more UEs or devices, such as one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, or14, or one or more of the devices1015described with reference toFIG. 10 or 11. The base station105-gmay, for example, include multiple base station antennas1555(e.g., an antenna array). The base station105-gmay communicate with the core network1545through the network communications module1540. The base station105-gmay also communicate with other base stations, such as the base stations105-hand105-i, using the base station communications module1530.

The base station wireless communication management module1220-bmay be configured to perform or control some or all of the features or functions described with reference toFIG. 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, or13related to wireless communication over one or more contention-based channels or one or more scheduled channels. The base station wireless communication management module1220-b, or portions of it, may include a processor, or some or all of the functions of the base station wireless communication management module1220-bmay be performed by the base station processor module1510or in connection with the base station processor module1510. In some examples, the base station wireless communication management module1220-bmay be an example of the wireless communication management module1220described with reference toFIG. 12 or 13.

FIG. 16is a block diagram of a MIMO communication system1600including a base station105-jand a UE115-h, in accordance with various aspects of the present disclosure. The MIMO communication system1600may illustrate aspects of the wireless communication system100described with reference toFIG. 1. The base station105-jmay be an example of aspects of the base station105described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, or15, or aspects of the device1205described with reference toFIG. 12 or 13. The base station105-jmay be equipped with antennas1634through1635, and the UE115-hmay be equipped with antennas1652through1653. In the MIMO communication system1600, the base station105-jmay be able to send data over multiple communication links at the same time. Each communication link may be called a “layer” and the “rank” of the communication link may indicate the number of layers used for communication. For example, in a 2×2 MIMO communication system where base station105-jtransmits two “layers,” the rank of the communication link between the base station105-jand the UE115-his two.

At the base station105-j, a transmit (Tx) processor1620may receive data from a data source. The transmit processor1620may process the data. The transmit processor1620may also generate control symbols or reference symbols. A transmit MIMO processor1630may perform spatial processing (e.g., precoding) on data symbols, control symbols, or reference symbols, if applicable, and may provide output symbol streams to the transmit modulators1632through1633. Each modulator1632through1633may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator1632through1633may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink (DL) signal. In one example, DL signals from modulators1632through1633may be transmitted via the antennas1634through1635, respectively.

The UE115-hmay be an example of aspects of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, or14, or aspects of the device1015described with reference toFIG. 10 or 11. At the UE115-h, the UE antennas1652through1653may receive the DL signals from the base station105-jand may provide the received signals to the modulator/demodulators1654through1655, respectively. Each modulator/demodulator1654through1655may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each modulator/demodulator1654through1655may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector1656may obtain received symbols from all the modulator/demodulators1654through1655, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive (Rx) processor1658may process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the UE115-hto a data output, and provide decoded control information to a processor1680, or memory1682.

The processor1680may in some cases execute stored instructions to instantiate a UE wireless communication management module1020-c. The UE wireless communication management module1020-cmay be an example of aspects of the wireless communication management module1020described with reference toFIG. 10, 11, or14.

On the uplink (UL), at the UE115-h, a transmit processor1664may receive and process data from a data source. The transmit processor1664may also generate reference symbols for a reference signal. The symbols from the transmit processor1664may be precoded by a transmit MIMO processor1666if applicable, further processed by the modulator/demodulators1654through1655(e.g., for SC-FDMA, etc.), and be transmitted to the base station105-jin accordance with the transmission parameters received from the base station105-j. At the base station105-j, the UL signals from the UE115-hmay be received by the antennas1634through1635, processed by the demodulators1632through1633, detected by a MIMO detector1636if applicable, and further processed by a receive processor1638. The receive processor1638may provide decoded data to a data output and to the processor1640or memory1642.

The processor1640may in some cases execute stored instructions to instantiate a base station wireless communication management module1220-c. The base station wireless communication management module1220-cmay be an example of aspects of the wireless communication management module1220described with reference toFIG. 12, 13, or15.

The components of the UE115-hmay, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted modules may be a means for performing one or more functions related to operation of the MIMO communication system1600. Similarly, the components of the base station105-jmay, individually or collectively, be implemented with one or more ASICs adapted to perform some or all of the applicable functions in hardware. Each of the noted components may be a means for performing one or more functions related to operation of the MIMO communication system1600.

FIG. 17is a flow chart illustrating an exemplary method1700for wireless communication, in accordance with various aspects of the present disclosure. For clarity, the method1700is described below with reference to aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, 14, or16, or aspects of one or more of the devices1015described with reference toFIG. 10 or 11. In some examples, a UE or device may execute one or more sets of codes to control the functional elements of the UE or device to perform the functions described below. Additionally or alternatively, the UE or device may perform one or more of the functions described below using special-purpose hardware.

At block1705, a first transmission may be transmitted on a contention-based channel. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions. The operation(s) at block1705may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the contention-based transmission management module1035described with reference toFIG. 10 or 11.

At block1710, a scheduling request for the first transmission may be transmitted on a scheduled channel. The scheduling request may be transmitted prior to determining that an ACK message has been received for the first transmission. In some configurations, the scheduled channel may be a contention-free narrow-band channel whose payload is substantially smaller than the payload of the first transmission, regardless of the physical bandwidth of the narrow-band channel. The operation(s) at block1710may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the scheduled transmission management module1040described with reference toFIG. 10 or 11.

In some embodiments of the method1700, the first transmission and the scheduling request may be transmitted simultaneously. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission.

Thus, the method1700may provide for wireless communication. It should be noted that the method1700is just one implementation and that the operations of the method1700may be rearranged or otherwise modified such that other implementations are possible.

FIG. 18is a flow chart illustrating an exemplary method1800for wireless communication, in accordance with various aspects of the present disclosure. For clarity, the method1800is described below with reference to aspects of one or more of the UEs115described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, 14, or16, or aspects of one or more of the devices1015described with reference toFIG. 10 or 11. In some examples, a UE or device may execute one or more sets of codes to control the functional elements of the UE or device to perform the functions described below. Additionally or alternatively, the UE or device may perform one or more of the functions described below using special-purpose hardware.

At block1805, a first transmission may be transmitted on a contention-based channel. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions. When the size of a transmission to be made exceeds a maximum size of the first transmission, a request for transmission of a second transmission (e.g., a scheduling request) may be transmitted as part of the first transmission (e.g., a scheduling request for the second transmission may be transmitted in a MAC header of the first transmission). The operation(s) at block1805may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the contention-based transmission management module1035described with reference toFIG. 10 or 11.

At block1810, a scheduling request for the first transmission may be transmitted on a scheduled channel. The scheduling request may be transmitted prior to determining that an ACK message has been received for the first transmission. In some configurations, the scheduled channel may be a narrow-band channel. The operation(s) at block1810may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the scheduled transmission management module1040described with reference toFIG. 10 or 11.

In some embodiments of the method1800, the first transmission and the scheduling request may be transmitted simultaneously. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission.

At block1815, it may be determined whether an ACK message for the first transmission is received subsequent to transmitting the scheduling request at block1810. In some configurations, the determination made at block1825may be made at a scheduled time, upon expiration of a timer, or repeatedly (e.g., repeatedly within a defined time period or repeatedly for a defined number of times). When it is determined that the ACK message is received, the method1800may continue at block1820. When it is determined that the ACK message is not received, the method1800may continue at block1835. The operation(s) at block1815may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the ACK processing module1135described with reference toFIG. 11.

At block1820, it may be determined whether a transmission grant (e.g., an uplink grant) is received in response to transmitting a request for transmission of a second transmission at block1805. In some cases, the ACK message and the transmission grant may be received as part of a single transmission. When it is determined that the transmission grant is received, the method1800may continue at block1825. When it is determined that the transmission grant is not received, the method1800may continue at block1830. The operation(s) at block1820may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the transmission grant processing module1140described with reference toFIG. 11.

At block1825, a second transmission may be transmitted on the scheduled channel according to the transmission grant. The method1800may then end or continue with the performance of other operations at block1830. The operation(s) at block1825may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the scheduled transmission management module1040described with reference toFIG. 10 or 11.

At block1830, the method1800may end or continue with the performance of other operations. The operation(s) at block1830may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16.

Additional details of the operations performed at blocks1805,1810,1815,1820,1825, and/or1830are described with reference toFIG. 10. Additional details of the operations performed at blocks1805,1810,1815,1820, and/or1830are described with reference toFIG. 4 or 8.

At block1835, it may be determined whether a transmission grant (e.g., an uplink grant) is received in response to transmitting the scheduling request. In some configurations, the determination made at block1835may be made at a scheduled time, upon expiration of a timer, or repeatedly (e.g., repeatedly within a defined time period or repeatedly for a defined number of times). When it is determined that the transmission grant is received, the method1800may continue at block1840. When it is determined that the transmission grant is not received, the method1800may be repeated (e.g., the flow of the method1800may be redirected to block1805, or the flow of the method1800may be directed to block1845). When repeating the method1800in some instances, the scheduling request may be retransmitted on the scheduled channel contemporaneously with repeating transmission of the first transmission. When repeating the method1800in other instances, the scheduling request may be retransmitted in accordance with a scheduling request transmission periodicity. The operation(s) at block1835may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the transmission grant processing module1140described with reference toFIG. 11.

At block1840, the first transmission may be retransmitted on the scheduled channel according to the transmission grant. The method1800may then end or continue with the performance of other operations at block1830. The operation(s) at block1840may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the scheduled transmission management module1040described with reference toFIG. 10 or 11.

Additional details of the operations performed at blocks1805,1810,1815,1835,1840, and/or1830are described with reference toFIG. 5 or 9.

At block1845, different transmission parameters may be selected for transmitting the first transmission on the contention-based channel or for retransmitting the scheduling request on the scheduled channel, such that the first transmission or scheduling request is retransmitted using different transmission parameters during a repetition of the method1800. Alternatively, the first transmission or scheduling request may be transmitted using the same transmission parameters used for a previous transmission of the first transmission or scheduling request. The operation(s) at block1845may be performed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the transmission parameter selection module1145described with reference toFIG. 11.

In some configurations, the flow of the method1800may be redirected to block1805or directed to block1845, from block1835, following expiration of a wait time (e.g., expiration of wait time prior to receiving at least one of an ACK message or a transmission grant). In some examples, the wait time may commence based at least in part on one of transmitting the first transmission at block1805, or transmitting the scheduling request at block1810. The wait time may be managed using the wireless communication management module1020described with reference toFIG. 10, 11, 14, or16, or the wait time management module1150described with reference toFIG. 11.

Additional details of the operations performed at blocks1805,1810,1815,1835,1845, and/or1830are described with reference toFIG. 6.

Thus, the method1800may provide for wireless communication. It should be noted that the method1800is just one implementation and that the operations of the method1800may be rearranged or otherwise modified such that other implementations are possible.

In some embodiments, aspects of the methods1700and1800described with reference toFIGS. 17 and 18may be combined.

FIG. 19is a flow chart illustrating an exemplary method1900for wireless communication, in accordance with various aspects of the present disclosure. For clarity, the method1900is described below with reference to aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, 15, or16, or aspects of one or more of the devices1205described with reference toFIG. 12 or 13. In some examples, a base station or device may execute one or more sets of codes to control the functional elements of the base station or device to perform the functions described below. Additionally or alternatively, the base station or device may perform one or more of the functions described below using special-purpose hardware.

At block1905, a scheduling request for a first transmission may be received on a scheduled channel from a wireless device (e.g., a UE). In some configurations, the scheduled channel may be a narrow-band channel. The operation(s) at block1905may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the scheduled transmission reception management module1240described with reference toFIG. 12 or 13.

At block1910, a transmission of a transmission grant to the wireless device may be withheld upon decoding a reception of the first transmission on a contention-based channel. At block1915, the transmission grant may be transmitted to the wireless device upon failing to decode the reception of the first transmission on the contention-based channel. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions. The operation(s) at block1910or1915may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the transmission grant management module1250described with reference toFIG. 12 or 13.

In some embodiments of the method1900, the first transmission and the scheduling request may be received simultaneously. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission.

Thus, the method1900may provide for wireless communication. It should be noted that the method1900is just one implementation and that the operations of the method1900may be rearranged or otherwise modified such that other implementations are possible.

FIG. 20is a flow chart illustrating an exemplary method2000for wireless communication, in accordance with various aspects of the present disclosure. For clarity, the method2000is described below with reference to aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, 15, or16, or aspects of one or more of the devices1205described with reference toFIG. 12 or 13. In some examples, a base station or device may execute one or more sets of codes to control the functional elements of the base station or device to perform the functions described below. Additionally or alternatively, the base station or device may perform one or more of the functions described below using special-purpose hardware.

At block2005, it may be determined whether a first transmission is received on a contention-based channel from a wireless device (e.g., a UE). When it is determined that the first transmission is received, the method2000may continue at block2010. When it is determined that the first transmission is not received, the method2000may continue at block2030. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions. The operation(s) at block2005may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the contention-based transmission reception management module1235described with reference toFIG. 12 or 13.

At block2010, an attempt to decode the reception of the first transmission (e.g., a first attempt to decode the first transmission) may be made. At block2015, it may be determined whether the reception of the first transmission was decoded at block2010. When the reception of the first transmission is decoded, the method2000may continue at block2020. When the reception of the first transmission is not decoded (i.e., after failing the first attempt to decode the first transmission), the method2000may continue at block2030. The operation(s) at block2010or2015may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the decoding management module1335described with reference toFIG. 13.

At block2020, an ACK message for the first transmission may be transmitted upon decoding the reception of the first transmission. The operation(s) at block2020may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the ACK management module1245described with reference toFIG. 12 or 13.

At block2025, the method2000may end or continue with the performance of other operations. The operation(s) at block2025may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16.

At block2030, it may be determined whether a scheduling request for the first transmission is received on a scheduled channel from the wireless device. When it is determined that the scheduling request is received (e.g., after the scheduling request is decoded), the method2000may include withholding transmission of a transmission grant to the wireless device and continuing at block2035. When it is determined that the scheduling request is not received, the method2000may continue at block2025. In some configurations, the scheduled channel may be a narrow-band channel. The operation(s) at block2230may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the scheduled transmission reception management module1240described with reference toFIG. 12 or 13.

At block2035, the flow of the method2000may be directed based on reception of the first transmission at block2005. When it is determined at block2005that the first transmission is received, block2035may direct the flow of the method2000to block2040. When it is determined at block2005that the first transmission is not received, block2035may direct the flow of the method2000to block2050. The operation(s) at block2035may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16.

At block2040, and after decoding the scheduling request at block2030, an attempt to decode the reception of the first transmission (e.g., a second attempt to decode the first transmission (e.g., the contention based transmission) may be made. At block2045, it may be determined whether the reception of the first transmission was decoded at block2040. When the reception of the first transmission is decoded, transmission of a transmission grant to the wireless device may be withheld, and the method2000may continue at block2020. When the reception of the first transmission is not decoded (i.e., after failing the second attempt to decode the first transmission), the method2000may continue at block2050. The operation(s) at block2040may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the decoding management module1335described with reference toFIG. 13.

At block2050, a transmission grant for the first transmission may be transmitted to the wireless device upon failing to decode the reception of the first transmission on the contention-based channel. The operation(s) at block2050may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the transmission grant management module1250described with reference toFIG. 12 or 13.

In some embodiments of the method2000, the first transmission and the scheduling request may be received simultaneously. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission.

Thus, the method2000may provide for wireless communication. It should be noted that the method2000is just one implementation and that the operations of the method2000may be rearranged or otherwise modified such that other implementations are possible.

FIG. 21is a flow chart illustrating an exemplary method2100for wireless communication, in accordance with various aspects of the present disclosure. For clarity, the method2100is described below with reference to aspects of one or more of the base stations105described with reference toFIG. 1, 4, 5, 6, 7, 8, 9, 15, or16, or aspects of one or more of the devices1205described with reference toFIG. 12 or 13. In some examples, a base station or device may execute one or more sets of codes to control the functional elements of the base station or device to perform the functions described below. Additionally or alternatively, the base station or device may perform one or more of the functions described below using special-purpose hardware.

At block2105, a first transmission may be received on a contention-based channel from a wireless device (e.g., a UE). The first transmission may include a request for transmission of a second transmission. In some configurations, the contention-based channel may at least partially overlap, in time or frequency, a channel available for scheduled transmissions. In other configurations, the contention-based channel may include a channel that does not overlap, in time or frequency, a channel available for scheduled transmissions. The operation(s) at block2105may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the contention-based transmission reception management module1235described with reference toFIG. 12 or 13.

At block2110, an ACK message for the first transmission, and a transmission grant for transmission of the second transmission on a scheduled channel, may be transmitted to the wireless device. In some configurations, the scheduled channel may be a narrow-band channel. The operation(s) at block2110may be performed using the wireless communication management module1220described with reference toFIG. 12, 13, 15, or16, or the ACK management module1245or transmission grant management module1250described with reference toFIG. 12 or 13.

In some embodiments of the method2200, the first transmission and the scheduling request may be received simultaneously. In some embodiments, the first transmission may include at least one of an OFDMA transmission, a CDMA transmission, or an SDMA transmission.

Thus, the method2100may provide for wireless communication. It should be noted that the method2100is just one implementation and that the operations of the method2100may be rearranged or otherwise modified such that other implementations are possible.

In some embodiments, aspects of two or more of the methods1900,2000, or2100described with reference toFIG. 19, 20, or21may be combined.