The data recovery from sub-carriers gradients (DRSG) of a received OFDM signal affected by deterministic and random distortions introduced by a transmission link, contributes a method and a circuit for utilizing gradients characterizing shapes of OFDM sub-carriers comprised in such OFDM signal for recovering data symbols transmitted originally.

Certain aspects of the present disclosure relate to methods and apparatus for performing one or more over the air calibration procedures for reciprocity based uplink MIMO transmissions, for example, in new radio (NR).

A method in a communication network includes an access point, using a multiple input multiple output antenna configuration, sending out a sounding packet to a plurality of client stations. The client stations determine a channel estimation of the sounding packet, but only a channel estimation of a portion of the entire sounding packet to avoid processing the entire packet. The resulting partial estimation is sent to the access point for using in transmit beamforming. In other examples, the client station sends a reverse link sounding packet over a portion a channel having a bandwidth less than the sounding packet, and from this the access point determines partial channel estimations and transmit beamforming conditions.

The Data Recovery with Inverse Transformation (DRIT) comprises methods and systems for reversing transmission channel transfer function in order to achieve a direct recovery of original data from a received signal distorted by a transmission link.

This application presents a direct data recovery from subspaces or parameters subranges of a received OFDM signal preidentified as corresponding to specific data symbols, by applying adaptive inverse signal transformation (AIST) method for reversing both original data coding and deterministic and random distortions introduced by a transmission channel, wherein both reversals are achieved by the same conversion of the subspaces or parameter subranges into data transmitted originally in order to eliminate an intermediate recovery of signals or parameters transmitted originally within the received OFDM signal. The AIST includes using both amplitudes and gradients of amplitudes of OFDM tone signals.

The data recovery from gradients (DRG) of sub-carriers of a received OFDM signal affected by deterministic and random distortions introduced by a transmission link, contributes a method and a system for utilizing gradients characterizing shapes of OFDM sub-carriers comprised in such OFDM signal for recovering data symbols transmitted originally.

A wireless cellular base station (BS) transmitter transmits a downlink calibration pilot symbol. A receiver receives from a user equipment (UE) an uplink calibration pilot symbol and an effective downlink channel estimate transmitted by the UE. The effective downlink channel estimate is computed by the UE using the downlink calibration pilot symbol received from the BS. Processing devices compute an effective uplink channel estimate using the uplink calibration pilot symbol received from the UE and compute channel reciprocity calibration coefficients using the effective downlink channel estimate received from the UE and the effective uplink channel estimate computed by the BS. The BS includes multiple antennas, and the BS computes the channel reciprocity calibration coefficients for each antenna. Alternatively, the uplink channel estimate received by the BS is an inverted version of the effective downlink channel estimate, which the processing devices use for channel reciprocity compensation.

The data recovery from sub-carriers gradients (DRSG) of a received OFDM signal affected by deterministic and random distortions introduced by a transmission link, contributes a method and a circuit for utilizing gradients characterizing shapes of OFDM sub-carriers comprised in such OFDM signal for recovering data symbols transmitted originally.

A method, system, or transmitting device including at least two antennas (e.g., orthogonally polarized antennas) that derives the precoding for each of the at least two antennas. The transmission signal provided to each antenna is based on an individual precoder for each antenna that is based on the signals received by the particular antenna.

The data recovery from sub-carriers (DRSC) of a received OFDM signal, contributes a method and a circuit for utilizing parameters of OFDM sub-carriers comprised in the received OFDM signal or subspaces comprising the OFDM sub-carriers for recovering transmitted data symbols from the received OFDM signal affected by deterministic and random distortions introduced by a transmission link.