TIME-FREQUENCY DIFFERENTIAL ENCODING FOR MULTICARRIER SYSTEM

摘要

Method for transmitting blocks of data symbols via a transmission carrier divided into a plurality of parallel subcarriers spaced in frequency direction. The inventive method combines both differential encoding in frequency direction and differential encoding in time direction in order to combine the advantages of both modulation schemes. A first subset of data symbols, starting from a predefined primary subcarrier symbol position, is differentially encoded in frequency direction in order to provide primary subcarrier symbols for all subcarriers thereafter, the primary subcarrier symbols are differentially encoded in time direction with a second subset of the data symbols, thus providing secondary data symbols. Subcarrier vectors of subcarrier symbols are transformed into the time domain and transmitted via the transmission carrier. Further, a data value describing the transmission quality of the transmission channel may be periodically received via a returning channel. And the first subset of data symbols for encoding in frequency direction may be selected in accordance with these channel conditions. The channel conditions may include information on the extent of time variance of the transmission channel.