| 摘要 |
A receiver receives a received signal from a communication link, the received signal comprising a stream of symbols modulated onto a carrier, each of the stream symbols selected from a constellation of symbols to represent a plurality of encoded data bits. The receiver comprises a demodulator to produce a stream of received symbols derived from the received signal; a channel decoder to produce a received stream of data bits derived from the stream of received symbols; and a memory device to store information related to the plurality of symbols in the constellation. For each of the symbols in the stream of received symbols, the demodulator: determines which of the plurality of symbols in the constellation is a respective closest symbol to that received symbol; identifies a respective nearest neighbor symbol for each data bit represented by the closest symbol for that received symbol based on the information stored in the memory device; and for each data bit represented by the respective closest symbol for that received symbol, subtracts the distance between the respective closest symbol and that received symbol from the distance between the respective nearest neighbor symbol and that received symbol in order to produce respective soft bits for that received symbol.
|
