This application provides a communication method for a wireless fidelity Wi-Fi system and an apparatus, and relates to the field of communication technologies, to improve an anti-interference capability of an IoT device, and improve a coverage capability and a wall penetration capability. The communication method for a wireless fidelity Wi-Fi system includes: generating a Wi-Fi frame including a preamble, where a synchronization sequence of the preamble includes at least one extension code, and the extension code includes N symbols generated based on a Barker code, where N=?*M, M is a chip length of the Barker code, and ? is a positive integer; and transmitting the Wi-Fi frame.

A method and apparatus may be used in wireless communications. The apparatus may be an access point (AP), and may transmit a power save frame. The power save frame may include one or more Uplink (UL) Transmission Times (ULT)s. The apparatus may determine that a station (STA) did not transmit during its respective ULT. The AP may transmit another power save frame. The other power save frame may include a modified ULT. The modified ULT may be for a STA that did not transmit during its respective ULT. The other power save frame may include an unmodified ULT. The unmodified ULT may be for a STA that did not transmit.

The invention relates to a technique for performing a random access procedure over a radio interface, for example between a mobile terminal and a radio base station of a mobile network. A method aspect of the invention comprises the steps of transmitting a synchronization request for synchronization information; receiving synchronization information in response to the synchronization request; and transmitting, based on at least one transmission parameter adjusted in accordance with the synchronization information, a resource request for data transmission resources.

A method and apparatus may be used in wireless communications. The apparatus may be an access point (AP), and may transmit a power save frame. The power save frame may include one or more Uplink (UL) Transmission Times (ULT)s. The apparatus may determine that a station (STA) did not transmit during its respective ULT. The AP may transmit another power save frame. The other power save frame may include a modified ULT. The modified ULT may be for a STA that did not transmit during its respective ULT. The other power save frame may include an unmodified ULT. The unmodified ULT may be for a STA that did not transmit.

Methods, systems, and devices for wireless communication are described. A wireless communications system may support techniques for using non-staggered reference signals to increase the efficiency of the system and reduce the complexity of channel estimation. A base station may schedule a transmission to a user equipment (UE) including pilot tones mapped to a first symbol and a second symbol. In some cases, the pilot tones on the first and second symbols may be non-contiguous, and the base station may scramble the pilot tones on the first and second symbols according to the same scrambling sequence. In other cases, the pilot tones on the first and second symbols may be contiguous, and the pilot tones may be scrambled according to the same or different scrambling sequences. These techniques may result in reduced complexity for interference estimation and channel estimation at a UE.

A method for transmitting a signal for cell searching in a mobile communication system having a multi-cell environment includes transmitting the signal to one or more receiving party devices within a cell, wherein the signal is used for a synchronization of the one or more receiving party devices within the cell, the signal is defined by a combination of a first code sequence derived from a first index and a second code sequence derived from a second index, and an identity of the cell is used for defining the combination of the first code sequence and the second code sequence.

A data transmission switch configured to be carried onboard an aircraft comprises: at least one input configured to receive data from a flight management computer on a first transmission channel, the channel functioning in multidirectional mode; at least one output configured to transmit the data to at least one avionic equipment on a second transmission channel, the switch further comprising a transducer configured to generate instructions for synchronization of the second transmission channel. The invention enables retrofitting to aircraft with an old avionic system under very economic conditions.

A method and apparatus may be used in wireless communications. The apparatus may he an access point (AP), and may transmit a power save frame. The power save frame may include one or more Uplink (UL) Transmission Times (ULT)s. The apparatus may determine that a station (STA) did not transmit during its respective ULT. The AP may transmit another power save frame. The other power save frame may include a modified ULT. The modified ULT may be for a STA that did not transmit during its respective ULT. The other power save frame may include an unmodified ULT. The unmodified ULT may be for a STA that did not transmit.

A communication device has a transmission/reception unit and a communication processing unit. The transmission/reception unit is configured to conform to a plurality of communication methods. The communication processing unit selects one of the plurality of communication methods with respect to each time slot based on device time in accordance with a predetermined selection rule, to perform communication via the transmission/reception unit by the selected communication method. In time synchronization master processing, a first communication device gives device time of the device itself as a time stamp to a time synchronization request signal and transmits the time synchronization request signal. In time synchronization slave processing, a second communication device receives the time synchronization request signal and calibrates the device time of the device itself based on the time stamp in the time synchronization request signal.

Methods and apparatus that may be used to provide timestamps to physical layer devices are provided. One method includes obtaining a time value from a clock associated with a physical layer device that is communicatively coupled to a primary data packet switch. The method further includes adding a processing time to the time value to generate a timestamp and transmitting the timestamp to a multiplexer circuit. The method further includes writing the timestamp in parallel from the multiplexer circuit to a plurality of external physical layer devices that are communicatively coupled to a secondary data packet switch and are located external to a housing of the secondary data packet switch.