Abstract: A method of selecting access point, suitable for a communication device, includes following operations: (a) monitoring a channel of at least one frequency band; (b) calculating a first count that the channel is detected to be in an occupied state; (c) calculating a second count that the channel is detected to have an ambient noise; (d) repeating steps (a) through (c) to obtain the first count and the second count of each of a plurality of channels used by a plurality of access points; (e) obtaining a plurality of received signal strength indications (RSSIs) of the plurality of access points, respectively; and (f) selecting a target channel from the plurality of channels and a target access point from the plurality of access points to perform connection according to the plurality of RSSIs and the first count and the second count of each of the plurality of channels.

Abstract: A computing device includes: a storage circuit, for storing an arbitration interframe space (AIFS) time, at least one expected value of at least one backoff time, a preamble time, a short interframe space (SIFS) time and an acknowledgement (ACK) time; a first computing circuit, for computing a payload time according to a packet length and a packet rate; a second computing circuit, coupled to the storage circuit and the first computing circuit, for computing at least one packet transmission time according to the AIFS time, the at least one expected value of the at least one backoff time, the preamble time, the SIFS time, the ACK time and the payload time; and a third computing circuit, coupled to the second computing circuit, for computing a total packet transmission time according to the at least one packet transmission time and an estimated packet error rate.

Abstract: A wireless transceiver device includes a communication module and a processor. The communication module is used for receiving and demodulating a radio frequency signal from a wireless signal transmitting-receiving end into a first data frame. The processor is coupled to the communication module and used for performing the following operations: obtaining a first modulation order from the first data frame; determining a second modulation order corresponding to a second data frame that is to be transmitted by the wireless transceiver device; and determining a transmission mode from a frame transmission rate table according to a smaller one of the first modulation order and the second modulation order for the wireless transceiver device to send a response frame to the wireless signal transmitting-receiving end in response to the first data frame.

Abstract: The present application provides an unmanned aerial vehicle (UAV) for a long duration flight. An exemplary UAV may include a UAV body assembly. The UAV may also include a flight control system (FCS) coupled to the UAV body assembly. The UAV may further include a motor coupled to the UAV body assembly at one end and coupled to a propeller at the other end. The FCS is communicatively connected to the motor. A center of gravity (CG) of the UAV is at a point between 21% and 25% of a mean aerodynamic chord (MAC) of the UAV.

Abstract: The present application provides a system for unmanned aerial vehicle (UAV) parachute landing. An exemplary system includes a detector configured to detect at least one of a flight speed, a wind speed, a wind direction, a position, a height, and a voltage of a UAV. The system also includes a memory storing instructions and a processor configured to execute the instructions to cause the system to: determine whether to open a parachute of the UAV in accordance with a criterion, responsive to the determination to open the parachute of the UAV, stop a motor of the UAV that spins a propeller of the UAV, and open the parachute of the UAV after stopping the motor of the UAV for a first period.

Abstract: A computing device includes: a storage circuit, for storing an arbitration interframe space (AIFS) time, at least one expected value of at least one backoff time, a preamble time, a short interframe space (SIFS) time and an acknowledgement (ACK) time; a first computing circuit, for computing a payload time according to a packet length and a packet rate; a second computing circuit, coupled to the storage circuit and the first computing circuit, for computing at least one packet transmission time according to the AIFS time, the at least one expected value of the at least one backoff time, the preamble time, the SIFS time, the ACK time and the payload time; and a third computing circuit, coupled to the second computing circuit, for computing a total packet transmission time according to the at least one packet transmission time and an estimated packet error rate.

Abstract: The present application provides a system for unmanned aerial vehicle (UAV) parachute landing. An exemplary system includes a detector configured to detect at least one of a flight speed, a wind speed, a wind direction, a position, a height, and a voltage of a UAV. The system also includes a memory storing instructions and a processor configured to execute the instructions to cause the system to: determine whether to open a parachute of the UAV in accordance with a criterion, responsive to the determination to open the parachute of the UAV, stop a motor of the UAV that spins a propeller of the UAV, and open the parachute of the UAV after stopping the motor of the UAV for a first period.

Abstract: A method used for controlling a wireless communication system includes receiving a packet, demodulating the packet to obtain a first channel characteristic index and a second channel characteristic index of the wireless communication system, selecting a length of a guard interval according to the first channel characteristic index, and selecting a length of a long training field according to the second channel characteristic index. When signal quality corresponding to the packet is higher, the length of the guard interval is shorter, and the length of the long training field is shorter.

Abstract: A method of selecting access point, suitable for a communication device, includes following operations: (a) monitoring a channel of at least one frequency band; (b) calculating a first count that the channel is detected to be in an occupied state; (c) calculating a second count that the channel is detected to have an ambient noise; (d) repeating steps (a) through (c) to obtain the first count and the second count of each of a plurality of channels used by a plurality of access points; (e) obtaining a plurality of received signal strength indications (RSSIs) of the plurality of access points, respectively; and (f) selecting a target channel from the plurality of channels and a target access point from the plurality of access points to perform connection according to the plurality of RSSIs and the first count and the second count of each of the plurality of channels.

Abstract: A method used for controlling a wireless communication system includes receiving a packet, demodulating the packet to obtain a first channel characteristic index and a second channel characteristic index of the wireless communication system, selecting a length of a guard interval according to the first channel characteristic index, and selecting a length of a long training field according to the second channel characteristic index. When signal quality corresponding to the packet is higher, the length of the guard interval is shorter, and the length of the long training field is shorter.

Abstract: The present application provides an unmanned aerial vehicle (UAV) for a long duration flight. An exemplary UAV may include a UAV body assembly. The UAV may also include a flight control system (FCS) coupled to the UAV body assembly. The UAV may further include a motor coupled to the UAV body assembly at one end and coupled to a propeller at the other end. The FCS is communicatively connected to the motor. A center of gravity (CG) of the UAV is at a point between 21% and 25% of a mean aerodynamic chord (MAC) of the UAV.

Abstract: The present application provides an unmanned aerial vehicle (UAV) for a long duration flight. An exemplary UAV may include a UAV body assembly. The UAV may also include a flight control system (FCS) coupled to the UAV body assembly. The UAV may further include a motor coupled to the UAV body assembly at one end and coupled to a propeller at the other end. The FCS is communicatively connected to the motor. A center of gravity (CG) of the UAV is at a point between 21% and 25% of a mean aerodynamic chord (MAC) of the UAV.

Abstract: The present application provides a system for unmanned aerial vehicle (UAV) parachute landing. An exemplary system includes a detector configured to detect at least one of a flight speed, a wind speed, a wind direction, a position, a height, and a voltage of a UAV. The system also includes a memory storing instructions and a processor configured to execute the instructions to cause the system to: determine whether to open a parachute of the UAV in accordance with a criterion, responsive to the determination to open the parachute of the UAV, stop a motor of the UAV that spins a propeller of the UAV, and open the parachute of the UAV after stopping the motor of the UAV for a first period.

Abstract: The present application provides an unmanned aerial vehicle (UAV) for a long duration flight. An exemplary UAV may include a UAV body assembly. The UAV may also include a flight control system (FCS) coupled to the UAV body assembly. The UAV may further include a motor coupled to the UAV body assembly at one end and coupled to a propeller at the other end. The FCS is communicatively connected to the motor. A center of gravity (CG) of the UAV is at a point between 21% and 25% of a mean aerodynamic chord (MAC) of the UAV.