A data transmission method and an apparatus relate to the communications field and are applied to data transmission to effectively reduce a collision reoccurrence probability after a device in a licensed-assisted access using Long Term Evolution (LAA-LTE) system preempts an unlicensed spectrum and collides with another device. A first device adjusts a detection moment or a quantity of detection times of clear channel assessment (CCA) of a channel in an unlicensed spectrum after the first device determines that the first device collides with another device when occupying the channel in the unlicensed spectrum to transmit data, and the first device occupies, according to an adjusted detection moment or an adjusted quantity of detection times of CCA of the channel in the unlicensed spectrum, the channel in the unlicensed spectrum to transmit data.

The present invention relates to wireless networks and more specifically to systems and methods for selecting available channels free of radar signals from a plurality of 5 GHz radio frequency channels. In non-limiting embodiments, exemplary systems, methods, and apparatuses are provided that can facilitate reducing false detections and/or network downtime in exemplary mesh networks employing dynamic frequency selection (DFS) channels. In a non-limiting aspect, radar information can be propagated among exemplary mesh nodes, including location information, to facilitate reducing false detections and/or network downtime in exemplary mesh networks. In addition, in further non-limiting aspects, exemplary embodiments can transmit signals to facilitate silencing one or more DFS channels and/or collaborative mesh node identification and/or discrimination of radar signals and false detections, among other non-limiting aspects provided.

Systems and methods are disclosed herein that relate to multiple candidate starting points for a transmit burst in unlicensed spectrum. In some embodiments, a method of operation of a radio access node for performing a transmit burst in an unlicensed spectrum comprises transmitting a transmit burst in an unlicensed spectrum, wherein the transmit burst spans multiple subframes/slots and the transmitting of the transmit burst starts at one of a plurality of candidate starting points defined in at least a first subframe/slot of the transmit burst that occurs after successful completion of a Listen-Before-Talk (LBT) procedure for the transmit burst. In this manner, a radio access node (e.g., an enhanced or evolved Node B (eNB) in Long Term Evolution (LTE)) has flexibility to transmit a downlink transmit burst starting at different starting positions based on LBT outcome.

A first wireless device may determine a bandwidth for transmitting a frame, calculate two or more Spatial Reuse (SR) parameter values for the bandwidth, set, using the SR parameter values, first and second SR fields of the frame based on the bandwidth and a channel center frequency in which the bandwidth is carried, and transmit the frame to a second wireless device on the bandwidth. The first and second SR fields may be set to a first value when the bandwidth is a 40 MHz bandwidth and the channel center frequency is in a 2.4 GHz band. The first and second SR fields may be set to the first value when the bandwidth is an 80+80 MHz bandwidth and the channel center frequency is in a 5 GHz band. The first value may be a minimum of SR parameter values for first and second bandwidths in the bandwidth.

A method for transmitting a physical layer protocol data unit (PPDU) and a device using the same are provided. The device receives a trigger frame for requesting a transmission of a high efficiency (HE) trigger-based (TB) PPDU and transmits the HE TB PPDU. A duration of the HE TB PPDU is calculated based on a duration of the trigger frame.

A wireless device generating a High-Efficiency (HE) PHY Protocol Data Unit (PPDU) for transmission sets a Packet Extension Disambiguity bit of an HE Signal-A (HE-SIG-A) field of the HE PPDU based on respective durations of a packet extension of the HE PPDU and a signal extension of the HE PPDU. The wireless device may determine whether a relationship

[00001]$T_{\mathrm{PE}}+\left(4\times .Math.\frac{\mathrm{TXTIME}-T_{\mathrm{SE}}-20}{4}.Math.-\left(\mathrm{TXTIME}-T_{\mathrm{SE}}-20\right)\right)\ge T_{\mathrm{SYM}}$

is satisfied, where T.sub.PE is the duration of the packet extension, TXTIME is a transmission time of the HE PPDU, T.sub.SE is the duration of the signal extension, and T.sub.SYM is a duration of symbols in a data field of the HE PPDU. The wireless device may set the Packet Extension Disambiguity bit to one when the relationship is satisfied; and to zero when the relationship is not satisfied.

The application provide an access method, including: sending, to an access point, a first frame that carries uplink transmission requirement information; and if a second frame that carries information about an uplink transmission resource is received from the access point within agreed time period, sending uplink multi-user transmission data to the access point, where the uplink multi-user transmission data is transmitted on the uplink transmission resource; or if the second frame is not received within an agreed time period, accessing, by a station, a channel in a contention access manner that is based on carrier sense CSMA/CA.

Disclosed are a method, an apparatus, and a system for performing channel access. In detail, provided are a method including: receiving uplink scheduling information; and when the user equipment has stopped an uplink transmission during the uplink transmission being performed according to the uplink scheduling information, to resume the uplink transmission, performing a second type channel access when a channel sensed by the user equipment is continuously idle after the uplink transmission has been stopped, and performing a first type channel access when the channel sensed by the user equipment is not continuously idle after the uplink transmission has been stopped, wherein the first type channel access comprises performing a random backoff after a channel sensing, and the second type channel access only comprises performing a channel sensing and an apparatus and a system therefor.

Wireless communications systems and methods related to sidelink communications in an unlicensed frequency band are provided. A user equipment (UE) receives, from a base station (BS), a first downlink control information (DCI) associated with a first listen-before-talk (LBT) time. The UE determines a first sidelink transmission opportunity for communicating in an unlicensed frequency band at the first LBT time based on the first DCI.

In a communication system having a plurality of user equipment (UE) devices that are operating in a contention based mode for device-to-device (D2D) communication, each UE device transmits a preferred transmission indicator when a condition for preferred transmission is met at the UE device. If a UE device receives a preferred transmission indicator, the UE device delays transmission of a D2D scheduling assignment (SA) to contend for communication resources for D2D communication. The length of the delay can be based on a number of preferred transmission indicators that are received. The preferred transmission indicator is based on a buffer size in one example.