BACKGROUND

The following relates generally to wireless communication, and more specifically to opportunistic extended channel uplink grants for ECC.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).

In contention based wireless communication systems, a listen before talk (LBT) procedure may be performed prior to transmission. For example, a device may perform one or more clear channel assessments (CCAs) on a channel by detecting a threshold energy level. In some cases, a transmitter may perform an extended CCA (eCCA) that includes multiple CCA measurements. In some networks, a base station may perform the eCCA to determine availability of a channel for uplink transmission by a user equipment (UE). That is, the base station may attempt eCCA on each channel, and send a grant for those channels that are available. However, this process may result in occasions where the UE is unable to transmit uplink data because the eCCA fails at the base station. This may delay transmissions or reduce the effective bandwidth of a channel.

SUMMARY

A wireless communication system may utilize a listen before talk (LBT) procedure prior to transmission. A base station may perform an enhanced clear channel assessment (eCCA) on one channel and a single clear channel assessment (CCA) on another channel. The base station may then send a grant for a user equipment (UE) to transmit on both channels. The UE may receive the grant, and perform a single CCA on the first channel and an eCCA on the second channel. The UE may then transmit uplink information on both the first channel and the second channel. That is, the base station may send an opportunistic grant for transmitting on the second channel even though it may not have passed eCCA at the base station. The UE may then use the channel if it passes an eCCA.

A method of wireless communication is described. The method may include receiving a scheduling message on a first channel, the scheduling message identifying the first channel and a second channel, performing a first channel clearance procedure on the first channel based at least in part on receiving the scheduling message on the first channel and performing a second channel clearance procedure on the second channel based at least in part on determining that the scheduling message has not been received on the second channel.

An apparatus for wireless communication is described. The apparatus may include means for receiving a scheduling message on a first channel, the scheduling message identifying the first channel and a second channel, means for performing a first channel clearance procedure on the first channel based at least in part on receiving the scheduling message on the first channel and means for performing a second channel clearance procedure on the second channel based at least in part on determining that the scheduling message has not been received on the second channel.

A further apparatus is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to receive a scheduling message on a first channel, the scheduling message identifying the first channel and a second channel, perform a first channel clearance procedure on the first channel based at least in part on receiving the scheduling message on the first channel and perform a second channel clearance procedure on the second channel based at least in part on determining that the scheduling message has not been received on the second channel.

A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions to cause a processor to receive a scheduling message on a first channel, the scheduling message identifying the first channel and a second channel, perform a first channel clearance procedure on the first channel based on receiving the scheduling message on the first channel and perform a second channel clearance procedure on the second channel based on determining that the scheduling message has not been received on the second channel.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, performing the first channel clearance procedure comprises: performing a single clear channel assessment (CCA) check, and performing an extended CCA (eCCA) check if the single CCA check is unsuccessful.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, performing the single CCA check comprises: determining whether the first channel is clear based on a single CCA.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting uplink (UL) data on the first channel based on the first channel clearance procedure.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, performing the second channel clearance procedure comprises: performing an eCCA check. In some examples of the method, apparatus, or non-transitory computer-readable medium described above, performing the second channel clearance procedure comprises: determining that a single CCA check is not sufficient to gain access to the second channel.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting UL data on the second channel based on the second channel clearance procedure, where the transmitted UL data comprises an indication of whether the first channel, the second channel or both are being used.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the scheduling message comprises a first UL grant for the first channel and a second UL grant for the second channel. In some examples of the method, apparatus, or non-transitory computer-readable medium described above, a first modulation and coding scheme (MCS) of the first UL grant is different from a second MCS of the second UL grant.

A method of wireless communication is described. The method may include determining that a first eCCA check on a first channel is successful and that a second eCCA check on a second channel is unsuccessful and transmitting a scheduling message on the first channel based on the determination, the scheduling message identifying the first channel and the second channel.

An apparatus for wireless communication is described. The apparatus may include means for determining that a first eCCA check on a first channel is successful and that a second eCCA check on a second channel is unsuccessful and means for transmitting a scheduling message on the first channel based on the determination, the scheduling message identifying the first channel and the second channel.

A further apparatus is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to determine that a first eCCA check on a first channel is successful and that a second eCCA check on a second channel is unsuccessful and transmit a scheduling message on the first channel based on the determination, the scheduling message identifying the first channel and the second channel.

A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions to cause a processor to determine that a first eCCA check on a first channel is successful and that a second eCCA check on a second channel is unsuccessful and transmit a scheduling message on the first channel based on the determination, the scheduling message identifying the first channel and the second channel.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for refraining from transmitting the scheduling message on the second channel based on the second eCCA check.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for identifying whether UL data is being transmitted on the first channel or the second channel or both. Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving the UL data on the first channel or the second channel based on the scheduling message.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the scheduling message comprises a first UL grant for the first channel and a second UL grant for the second channel. In some examples of the method, apparatus, or non-transitory computer-readable medium described above, a first MCS of the first UL grant is different from a second MCS of the second UL grant.

