A GSM satellite communication system is in communication with a first satellite having a first field of view including a first plurality of cells in which a plurality of active User Equipment (UEs) is located. The plurality of active UEs is in direct communication with the first satellite. The satellite communication system includes a first feeder link and a first tracking antenna configured to communicate with the plurality of active UEs via the first satellite directly serving the first plurality of cells; a first processing device configured to communicate with the plurality of active UEs; and a second processing device configured to normalize delay for a plurality of beam centers of the first plurality of cells, and provide the normalized delay to the first processing device.

A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.

A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect that at least a portion of reference signaling expected in a channel is not present in the channel. The UE may modify a Doppler estimation computation associated with the reference signaling based at least in part on detecting that at least the portion of the reference signaling is not present in the channel. Numerous other aspects are described.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect that at least a portion of reference signaling expected in a channel is not present in the channel. The UE may modify a Doppler estimation computation associated with the reference signaling based at least in part on detecting that at least the portion of the reference signaling is not present in the channel. Numerous other aspects are described.

A communication device providing CSI feedback in a wireless communication system includes a transceiver to receive downlink reference signals and downlink signals including a reference signal configuration. A processor estimates an explicit CSI in the frequency domain. The processor selects a Doppler-delay-beam precoder matrix for a composite Doppler-delay-beam three-stage precoder, which is based on one or more codebooks including one or more transmit-side spatial beam components, one or more delay components, and one or more Doppler-frequency components,

The processor calculates a CQI and/or a PMI and/or a rank indicator, RI, using the explicit CSI and the composite Doppler-delay-beam three-stage precoder, and reports the CSI feedback including the CQI, and/or the PMI and/or the RI. The one or more delay and/or Doppler-frequency components are defined by one or more sub-matrices of a DFT matrix or an oversampled DFT matrix.

A communication device providing CSI feedback in a wireless communication system includes a transceiver to receive downlink reference signals and downlink signals including a reference signal configuration. A processor estimates an explicit CSI in the frequency domain. The processor selects a Doppler-delay-beam precoder matrix for a composite Doppler-delay-beam three-stage precoder, which is based on one or more codebooks including one or more transmit-side spatial beam components, one or more delay components, and one or more Doppler-frequency components,

The processor calculates a CQI and/or a PMI and/or a rank indicator, RI, using the explicit CSI and the composite Doppler-delay-beam three-stage precoder, and reports the CSI feedback including the CQI, and/or the PMI and/or the RI. The one or more delay and/or Doppler-frequency components are defined by one or more sub-matrices of a DFT matrix or an oversampled DFT matrix.

Aspects of the subject disclosure may include, for example, a method, includes coordinating relay transmission of a modulated signal via relay links of a distributed antenna system to reduce an accumulated forwarding delay in forwarding the modulated signal through the relay links. One of the relay links of the distributed antenna system reconverts the spectral segment of the modulated signal for transmission to a communication device to which the modulated signal is directed.

Methods and apparatus reducing or eliminating the number of multipliers in Schnorr-Euchner expansion algorithms are disclosed. Methods and apparatus for implementing Schnorr-Euchner expansion algorithms with a reduced number of multipliers or without any multipliers are also disclosed. Also disclosed is a Schnorr-Euchner expansion method for a multiple-input multiple-output communication system. The method includes receiving, by a plurality of input terminals, a plurality of input signals. The method also includes detecting a symbol transmitted by each input signal. The detection includes identifying a list of possible symbols that may be transmitted by each input signal. A cost value for each possible symbol is determined based on a cost function. The cost function is implemented without requiring a multiplier. The possible symbol with a lowest cost value is identified as the transmitted symbol.

Methods and apparatus reducing or eliminating the number of multipliers in Schnorr-Euchner expansion algorithms are disclosed. Methods and apparatus for implementing Schnorr-Euchner expansion algorithms with a reduced number of multipliers or without any multipliers are also disclosed. Also disclosed is a Schnorr-Euchner expansion method for a multiple-input multiple-output communication system. The method includes receiving, by a plurality of input terminals, a plurality of input signals. The method also includes detecting a symbol transmitted by each input signal. The detection includes identifying a list of possible symbols that may be transmitted by each input signal. A cost value for each possible symbol is determined based on a cost function. The cost function is implemented without requiring a multiplier. The possible symbol with a lowest cost value is identified as the transmitted symbol.