Disclosed are a method and an apparatus for transmitting and receiving a synchronization signal in a communication system. According to an exemplary embodiment of the present disclosure, a method of transmitting a first synchronization signal, performed by a base station in the communication system, may comprise generating a base sequence; generating a modified sequence by inverting polarity of the base sequence; mapping the base sequence and the modified sequence to a first frequency region having a frequency higher than a center subcarrier and a second frequency region having a frequency lower the center subcarrier, so that the base sequence and the modified sequence are symmetric centering the center subcarrier located at a center frequency of a frequency domain of the synchronization signal; and transmitting the synchronization signal comprising the base sequence and the modified sequence to a terminal. Therefore, performance of the communication system can be improved.

A user terminal (UT) to transmit small amounts of data, the UT including: a packet including the data, where the packet is less than 128 bytes; a frequency synchronizer to synchronize a transmission frequency of an ASCMA return link connecting the UT with a satellite gateway; and an ASCMA transmitter to transmit, without acquiring timing synchronization with the satellite gateway from the UT, the packet modulated over the synchronized transmission frequency as an ASCMA waveform including a preamble to indicate a start of a transmission. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

A radio link monitoring method, the method includes: generating an indication indicating that a reference signal is not detected if the reference signal is not detected; and performing radio link monitoring according to the indication.

Disclosed are a method and apparatus for processing an uplink frequency offset of a communication system. The method on a base station side includes: demodulating a random access message sent by a terminal to obtain an initial Doppler frequency offset of the terminal and delivering the initial Doppler frequency offset to the terminal; receiving an uplink subframe signal sent by the terminal, estimating a residual Doppler frequency offset of the terminal on an uplink, obtaining a frequency retuning amount according to the residual Doppler frequency offset and delivering the frequency retuning amount to the terminal. The method on a terminal side includes: receiving an initial Doppler frequency offset sent by a base station, obtaining an initial uplink transmission frequency according to an initial downlink transmission frequency and the initial Doppler frequency offset and sending an uplink subframe signal; and receiving a frequency retuning amount sent by the base station, and obtaining a transmission frequency of a next uplink transmission according to the frequency retuning amount.

Control information (126) related to the reception of data (128) within a subframe (116) is transmitted over multiple subframes (113, 116) over multiple carrier (107, 108) from communication system infrastructure (102). A controller (134) in a mobile wireless communication device (104) reconstructs the control information (126) received over multiple subframes (113, 116) based on at least some control information (130) in a first physical control channel (118) in a first subframe (113) transmitted over a first carrier (107) and at least some other control information (132) in a second physical control channel (120) in a second subframe (116) transmitted over a second carrier (108).

In retrodirective wireless power delivery environments wireless power receivers generate and send beacon signals that are received by multiple antennas of a wireless power transmission system. The beacon signals provide the charger with timing information for wireless power transfers and also indicate directionality of the incoming signal. As discussed herein, the directionality information is employed when transmitting in order to focus energy (e.g., power wave delivery) on individual wireless power receiver clients. Techniques are described herein for reducing the burden of sampling the beacon signals across the multiple antennas and determining the directionality of the incoming wave. In some embodiments, the techniques leverage previously calculated values to simplify the receiver sampling.

A method for determining an angle of arrival (AOA) of a received signal is disclosed, comprising: generating a baseband information signal by mixing a received signal with a local oscillator (LO) signal, the received signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets; obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample; determining a transmitter phase offset based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; performing a plurality of phase measurements using a plurality of antennas to obtain a plurality of phase measurements; correcting the plurality of phase measurements based on the transmitter phase offset to produce a plurality of corrected phase measurement; and calculating an AOA of the received signal based on the difference between the plurality of corrected phase measurements.

Techniques are described for wireless communication at a wireless device. One method includes transmitting, during a TTI, a first message using a first MCS; and transmitting, during the TTI, a second message using a second MCS. The first message includes indications of a location, a heading, and a speed of the wireless device, and the second MCS is higher than the first MCS. Another method includes decoding a first message received during a TTI; performing a Doppler effect compensation for a second message based at least in part on the first message; and decoding the second message based at least in part on the Doppler effect compensation. The second message is also received during the TTI. The first message is decoded in accordance with a first MCS, and the second message is decoded in accordance with a second MCS, with the second MCS being higher than the first MCS.

A terminal is disclosed including a receiver that receives configuration information indicating a gap offset in subframe units related to a measurement gap (MG), and a shift time shorter than one subframe and related to the MG. The terminal further includes a processor that determines a timing of the MG based on the gap offset and the shift time. In other aspects, a radio communication method for a terminal and a base station are also disclosed.

Embodiments of this application provide a communication method, a communications apparatus, and a communications system, to determine a physical resource block (PRB) grid when a center frequency of a synchronization signal (SS) is inconsistent with a center frequency of a carrier. The method includes: receiving, by a terminal, an SS from a network device; determining, by the terminal, a first PRB grid based on the SS; receiving, by the terminal, first indication information from the network device, where the first indication information is used to indicate a first frequency offset between the first PRB grid and a second PRB grid; and determining, by the terminal, the second PRB grid based on the first PRB grid and the first frequency offset.