Listen-before-talk for LTE direct on unlicensed radio frequency spectrum band
First Claim
Patent Images
1. A method for wireless communication, comprising:
- performing, during a first subframe, a listen-before-talk (LBT) procedure on a channel in an unlicensed radio frequency spectrum band;
identifying a time period between completion of the LBT procedure and a boundary of a second subframe;
selecting a duration of a variable length message based at least in part on a fixed LBT procedure time, an actual LBT procedure time, and a Wi-Fi preamble time, the selected duration establishing synchronization to time align frames transmitted on the channel with licensed frames transmitted on a licensed channel of a licensed radio frequency spectrum band; and
transmitting, on the channel during the identified time period, a Wi-Fi preamble and the variable length message according to the selected duration such that the variable length message is time aligned with the boundary of the second subframe.
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Abstract
Methods, systems, and devices are described for direct device-to-device (D2D) communications in a subframe on a channel in an unlicensed radio frequency spectrum band. A user equipment (UE) may perform a listen-before-talk (LBT) procedure on the channel in the unlicensed radio frequency spectrum band. The UE may identify a time period between a completion of the LBT procedure and a boundary of a second subframe. The UE may transmit a Wi-Fi preamble and a variable length message on the channel during the identified timer period. The variable length message may include a duration that is time aligned with the boundary of the second subframe.
15 Citations
34 Claims
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1. A method for wireless communication, comprising:
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performing, during a first subframe, a listen-before-talk (LBT) procedure on a channel in an unlicensed radio frequency spectrum band; identifying a time period between completion of the LBT procedure and a boundary of a second subframe; selecting a duration of a variable length message based at least in part on a fixed LBT procedure time, an actual LBT procedure time, and a Wi-Fi preamble time, the selected duration establishing synchronization to time align frames transmitted on the channel with licensed frames transmitted on a licensed channel of a licensed radio frequency spectrum band; and transmitting, on the channel during the identified time period, a Wi-Fi preamble and the variable length message according to the selected duration such that the variable length message is time aligned with the boundary of the second subframe. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for wireless communication, comprising:
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a processor; memory in electronic communication with the processor; and instructions stored in the memory, the instructions being executable by the processor to; perform, during a first subframe, a listen-before-talk (LBT) procedure on a channel in an unlicensed radio frequency spectrum band; identify a time period between completion of the LBT procedure and a boundary of a second subframe; select a duration of a variable length message based at least in part on a fixed LBT procedure time, an actual LBT procedure time, and a Wi-Fi preamble time, the selected duration establishing synchronization to time align frames transmitted on the channel with licensed frames transmitted on a licensed channel in a licensed radio frequency spectrum band; and transmit, on the channel during the identified time period, a Wi-Fi preamble and the variable length message according to the selected duration such that the variable length message is time aligned with the boundary of the second subframe. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An apparatus for wireless communication, comprising:
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means for performing, during a first subframe, a listen-before-talk (LBT) procedure on a channel in an unlicensed radio frequency spectrum band; means for identifying a time period between completion of the LBT procedure and a boundary of a second subframe; means for selecting a duration of a variable length message based at least in part on a fixed LBT procedure time, an actual LBT procedure time, and a Wi-Fi preamble time, the selected duration establishing synchronization to time align frames transmitted on the channel with licensed frames transmitted on a licensed channel in a licensed radio frequency spectrum band; and means for transmitting, on the channel during the identified time period, a Wi-Fi preamble and the variable length message according to the selected duration such that the variable length message is time aligned with the boundary of the second subframe. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A non-transitory computer-readable medium storing code for wireless communication, the code executable by a processor to:
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perform, during a first subframe, a listen-before-talk (LBT) procedure on a channel in an unlicensed radio frequency spectrum band; identify a time period between completion of the LBT procedure and a boundary of a second subframe; select a duration of a variable length message based at least in part on a fixed LBT procedure time, an actual LBT procedure time, and a Wi-Fi preamble time, the selected duration establishing synchronization to time align frames transmitted on the channel with licensed frames transmitted on a licensed channel in a licensed radio frequency spectrum band; and transmit, on the channel during the identified time period, a Wi-Fi preamble and the variable length message according to the selected duration such that the variable length message is time aligned with the boundary of the second subframe. - View Dependent Claims (29, 30, 31, 32, 33, 34)
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Specification