| 摘要 |
Generalized Frequency Division Multiplexing (GFDM) can use a conventional QAM modulation but the required good time-frequency localization can result in distorted reconstruction of complex-valued symbols sent at Nyquist rate. To mitigate this problem the use of Offset-QAM has been proposed as solution, in particular with a non-symmetric conjugate-root pulse-shaping filter. However, the use of time shifting in conventional Offset-QAM reduces the effect of using guard sub-symbols to achieve low out-of-band radiation. Therefore the invention proposes to use a frequency-domain Offset-QAM, i.e. the real and imaginary part are shifted against each other in frequency by half a subcarrier bandwidth, which in turn allows the use of guard symbols, i.e. a cyclic prefix and/or a cyclic suffix of complex valued samples, to achieve low out-of-band emission. |
