The method involves sequentially encoding the plurality of data packets, which involves, for a data packet, obtaining a reference data packet, obtaining a mask packet indicative of which of the bits in the data packet are predictable and which of the bits in the data packet are not predictable obtaining change history data indicative of previously changed bits of the mask packet, determining an updated mask packet based on the mask packet, the data packet, and the reference data packet, determining updated change history data based on the change history data, the mask packet, and the updated mask packet, determining, as unpredictable bits, all those bits of the data packet that are indicated as not predictable by the updated mask packet, and generating an encoded data packet including a representation of the updated change history data and a representation of values of the unpredictable bits of the data packet.

A first value of a first data element in a first set of data elements is obtained, the first set of data elements being based on a first time sample of a signal. A second value of a second data element in a second set of data elements is obtained, the second set of data elements being based on a second, later time sample of the signal. A measure of similarity is derived between the first value and the second value. Based on the derived measure, a quantisation parameter useable in performing quantisation on data based on the first time sample of the signal is determined. Output data is generated using the quantisation parameter.

The method involves sequentially encoding the plurality of data packets, which involves, for a data packet, obtaining a reference data packet, obtaining a mask packet indicative of which of the bits in the data packet are predictable and which of the bits in the data packet are not predictable obtaining change history data indicative of previously changed bits of the mask packet, determining an updated mask packet based on the mask packet, the data packet, and the reference data packet, determining updated change history data based on the change history data, the mask packet, and the updated mask packet, determining, as unpredictable bits, all those bits of the data packet that are indicated as not predictable by the updated mask packet, and generating an encoded data packet including a representation of the updated change history data and a representation of values of the unpredictable bits of the data packet.

A first value of a first data element in a first set of data elements is obtained, the first set of data elements being based on a first time sample of a signal. A second value of a second data element in a second set of data elements is obtained, the second set of data elements being based on a second, later time sample of the signal. A measure of similarity is derived between the first value and the second value. Based on the derived measure, a quantisation parameter useable in performing quantisation on data based on the first time sample of the signal is determined. Output data is generated using the quantisation parameter.

A first value of a first data element in a first set of data elements is obtained, the first set of data elements being based on a first time sample of a signal. A second value of a second data element in a second set of data elements is obtained, the second set of data elements being based on a second, later time sample of the signal. A measure of similarity is derived between the first value and the second value. Based on the derived measure, a quantisation parameter useable in performing quantisation on data based on the first time sample of the signal is determined. Output data is generated using the quantisation parameter.

A first value of a first data element in a first set of data elements is obtained, the first set of data elements being based on a first time sample of a signal. A second value of a second data element in a second set of data elements is obtained, the second set of data elements being based on a second, later time sample of the signal. A measure of similarity is derived between the first value and the second value. Based on the derived measure, a quantisation parameter useable in performing quantisation on data based on the first time sample of the signal is determined. Output data is generated using the quantisation parameter.

A first value of a first data element in a first set of data elements is obtained, the first set of data elements being based on a first time sample of a signal. A second value of a second data element in a second set of data elements is obtained, the second set of data elements being based on a second, later time sample of the signal. A measure of similarity is derived between the first value and the second value. Based on the derived measure, a quantisation parameter useable in performing quantisation on data based on the first time sample of the signal is determined. Output data is generated using the quantisation parameter.

A first value of a first data element in a first set of data elements is obtained, the first set of data elements being based on a first time sample of a signal. A second value of a second data element in a second set of data elements is obtained, the second set of data elements being based on a second, later time sample of the signal. A measure of similarity is derived between the first value and the second value. Based on the derived measure, a quantisation parameter useable in performing quantisation on data based on the first time sample of the signal is determined. Output data is generated using the quantisation parameter.

New techniques are provided which reduce communication in private federated learning without the need for setting or tuning compression rates. Example on-the-fly methods automatically adjust the compression rate based on the error induced during training, while maintaining provable privacy guarantees through the use of secure aggregation and differential privacy.

A pre-equalized waveform generation device includes: a calibration waveform data outputting unit to output first waveform data for calibration and second waveform data for calibration represented by an expression having a different order of a time variable from an expression representing the first waveform data; a compression waveform data acquiring unit to acquire first compression waveform data modulated using the first waveform data and compressed via a compression transmission path and to acquire second compression waveform data modulated using the second waveform data and compressed via the compression transmission path; a compression characteristic estimating unit to estimate a compression characteristic of the compression transmission path by using the first compression waveform data and the second compression waveform data; and a pre-equalization calculation unit to calculate pre-equalized waveform data by using ideal compression waveform data generated on the basis of a signal waveform and the compression characteristic.