A derivation method includes: a transmission step of transmitting, to a wireless terminal, a first radio-wave signal according to an optical signal with a first wavelength and a second radio-wave signal according to an optical signal with a second wavelength; a communication start time information acquisition step of acquiring information on a first communication start time and information on a second communication start time; a reception time information acquisition step of acquiring information on a first reception time and information on a second reception time; a transmission time period derivation step of deriving a first round trip time and deriving a second round trip time; and an optical fiber length derivation step of deriving an optical fiber length, based on the first round trip time, the second round trip time, a group velocity or a group delay time of the optical signal with the first wavelength, and a group velocity or a group delay time of the optical signal with the second wavelength.

The disclosure relates to method and system for providing a MIMO transceiver in high speed mobility. The method includes dividing, by the wireless MIMO transmitter, transmission data into a plurality of transmit chains corresponding to an antenna. The method further includes generating for the plurality of transmit chains, a Circularly Pulse Shaped Orthogonal Time Frequency Space (CPS-OTFS) time frequency signal based on a first primary parameter. Value of the first primary parameter is determined based on a first predefined algorithm. The method further includes converting for the plurality of transmit chains, the CPS-OTFS time frequency signal to a CPS-OTFS time domain signal based on at least one of a plurality of secondary parameters. A first plurality of N-point Inverse Fast Fourier Transform (IFFT) are employed on the CPS-OTFS time frequency signal. The first plurality corresponds to the number of sub-carriers and N corresponds to a set of time symbols.

The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). Disclosed is a method of operating a base station in a non-terrestrial network telecommunication system, comprising the steps of: the base station detecting a block fading condition in a communication channel; the base station determining an average spectral efficiency value and reporting this to a user equipment in communication with the base station; and the base station allocating a modulation and coding scheme and activating a pre-emptive HARQ operation wherein the pre-emptive HARQ operation comprises the steps of: the base station determining an average fade duration; and sending multiple copies of a given data packet separated by a time at least equal to the average fade duration, with an MCS level matching a signal level associated with a non-fading condition of the communication channel.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

A control device causes a first transmission system in a MIMO transmission device to transmit a first transmitting-end clock transmission signal (first transmission signal), causes a second transmission system to transmit a second transmission signal, and causes the first transmission system to transmit a third transmission signal. The control device acquires a first phase value and a second phase value. The first phase value is a phase value of the second transmission signal received in the second reception system operating based on a receiving-end clock signal synchronous with a transmitting-end clock signal by the first transmission signal. The second phase value is a phase value of the third transmission signal received in the second reception system in synchronous operation. The control device calculates a first correction value for correcting a first delay amount set value of a delay adjustment processing unit based on the first and second phase values.

A wireless audio system including a transmitter using multiple antenna diversity techniques for different signal types is provided. Multipath performance may be optimized, along with improved spectral efficiency of the system.

For example, a wireless station may be configured to map a plurality of data symbols to Orthogonal Frequency-Division Multiplexing (OFDM) symbols in a plurality of spatial (space-time) streams, to map a plurality of modulated pilot sequences to the OFDM symbols according to a pilot mapping scheme, and to transmit an OFDM Multiple-Input-Multiple-Output (MIMO) transmission based on the plurality of spatial streams.

In a method of sending a frame using a cyclic shift diversity (CSD) sequence, a wireless device generates a frame comprising a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG) field, a repeated legacy signal (RL-SIG) field, an extremely high throughput signal A (EHT-SIG A) field, and an extremely high throughput signal B (EHT-SIG B) field. The wire device sends the frame through a set of transmit antennas by performing cyclic shift over the fields according to a CSD sequence. The number of transmit antennas is greater than 8. The number of cyclic shift diversities in the CSD sequence is equal to a number of the transmit antennas, and each cyclic shift diversity has a value that is a multiple of 12.5.

A radio device receives data from a base station that transmits a first radio signal, carrying a first data block, in a first time window, and a second radio signal, also carrying the first data block, in a different, second time window. The radio device comprises first and second antennas, receive circuitry, and a switch for selectively connecting the receive circuitry to the first antenna or to the second antenna. It is configured to sample the first radio signal, received by the first antenna in the first time window, to generate first sampled data; disconnect the first antenna from the receive circuitry and connect the second antenna; sample the second radio signal, received by the second antenna in the second time window, to generate second sampled data; and use both the first sampled data and the second sampled data to decode the first data block.

A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.