A method for reference signal configuration of a wireless communication system is provided. The method includes the following actions. An uplink channel is received by a base station from a user equipment (UE). A frequency offset and a coherence time effected by a phase noise and a Doppler shift are estimated by the base station in response to the uplink channel. A reference signal format is configured by the base station in response to the frequency offset and the coherence time effected by the phase noise and the Doppler shift. A physical uplink shared channel is configured by the UE in response to the reference signal format.

A method for reference signal configuration of a wireless communication system is provided. The method includes the following actions. An uplink channel is received by a base station from a user equipment (UE). A frequency offset and a coherence time effected by a phase noise and a Doppler shift are estimated by the base station in response to the uplink channel. A reference signal format is configured by the base station in response to the frequency offset and the coherence time effected by the phase noise and the Doppler shift. A physical uplink shared channel is configured by the UE in response to the reference signal format.

A method includes receiving a first signal pulse and determining a first frequency band and a first value of a first signal property that are associated with the first signal pulse. The method includes, in accordance with a determination that the first frequency band is a respective frequency band in a first predefined set of frequency bands, determining first data that is associated with the first frequency band. The method includes, in accordance with a determination that the first value of the first signal property is a respective value in a first predefined set of values of the first signal property, determining second data that is associated with the first value of the first signal property. The first signal pulse represents the first data and the second data. The first predefined set of frequency bands, in aggregate, are not contiguous.

A method includes receiving a first signal pulse and determining a first frequency band and a first value of a first signal property that are associated with the first signal pulse. The method includes, in accordance with a determination that the first frequency band is a respective frequency band in a first predefined set of frequency bands, determining first data that is associated with the first frequency band. The method includes, in accordance with a determination that the first value of the first signal property is a respective value in a first predefined set of values of the first signal property, determining second data that is associated with the first value of the first signal property. The first signal pulse represents the first data and the second data. The first predefined set of frequency bands, in aggregate, are not contiguous.

An illustrative embodiment disclosed herein is a method including estimating, by an endpoint, a first rate of change of a Doppler frequency offset during a downlink reception from a satellite associated with the Doppler frequency offset and applying, by the endpoint, a second rate of change of the Doppler frequency offset to an uplink transmission to the satellite. The second rate of change of the Doppler frequency offset compensates the first rate of change of the Doppler frequency offset.

An illustrative embodiment disclosed herein is a method including estimating, by an endpoint, a first rate of change of a Doppler frequency offset during a downlink reception from a satellite associated with the Doppler frequency offset and applying, by the endpoint, a second rate of change of the Doppler frequency offset to an uplink transmission to the satellite. The second rate of change of the Doppler frequency offset compensates the first rate of change of the Doppler frequency offset.

An illustrative embodiment disclosed herein is a satellite including a transceiver, a first antenna, a second antenna, and a switch to enable only the first antenna by electrically coupling the first antenna to the transceiver responsive to a satellite constellation having less than a threshold number of satellites and enable only the second antenna by electrically coupling the second antenna to the transceiver responsive to the satellite constellation having greater than the threshold number of satellites.

An illustrative embodiment disclosed herein is a method including determining, by a location server, a satellite constellation, a location of a target endpoint, and a next available time of the target endpoint. The method further includes determining, by the location server, a plurality of candidate satellites based on the satellite constellation, the location of the target endpoint, and the next available time of the target endpoint. The method further includes instructing, by the location server, a ground station to broadcast a downlink signal to the plurality of candidate satellites.

An illustrative embodiment disclosed herein is a method, by a satellite, including sending a downlink signal to a first endpoint and a second endpoint at a first time and receiving a first uplink signal from the first endpoint at a second time. The second time is based on a first delay value calculated by the first endpoint. The method further includes receiving a second uplink signal from the second endpoint at a third time. The third time is based on a second delay value calculated by the second endpoint. The method further includes calculating the first delay value and the second delay value based on one or more identifiers of the first endpoint and the second endpoint, respectively, and an algorithm and determining a first distance between the satellite and the first endpoint and a second distance between the satellite and the second endpoint.

A method and a device for pre-correction of a downlink signal are provided. The method comprises: on the basis of an obtained uplink frequency offset value of a first RRU and a second RRU corresponding to each client, determining a set of uplink frequency offset values corresponding to each RRU; when a downlink pre-correction period is reached, calculating an average uplink frequency offset value of the RRU; and on the basis of the average uplink frequency offset value of the RRU and a downlink pre-correction value in a previous pre-correction period, determining a downlink pre-correction value of the RRU in the current downlink pre-correction period.