Spectrally Precoded OFDM Without Guard Insertion
US$53.15
10000 in stock
SupportDescription
The nonguarded OFDM (NG-OFDM) signaling format, which is exactly OFDM without inserting guard subintervals, is considered to avoid the spectrum expansion and combined with spectral precoding to further achieve high spectrum compactness. In particular, spectral precoders are designed for NG-OFDM to provide very small spectral side lobes, and thus extremely compact signal spectrum, and associate the transmitted waveform with low peak-to-average power ratio. To reject IBI among received NG-OFDM blocks over dispersive channels, a guard subinterval in each received block is removed at the receiver, and this turns the resultant receiver as nonorthogonal over subcarrier sub channels, thus resulting in inter carrier interference (ICI). The corresponding channel capacity and linear minimum-mean-square-error (LMMSE) data estimation are analyzed. It is shown that the proposed spectrally precoded NG-OFDM (SP-NG-OFDM) system can provide channel capacity very close to nonprecoded and spectrally precoded OFDM using the cyclic prefix (CP-OFDM) when the removal guard ratio is small, and much higher channel capacity per unit bandwidth than spectrally precoded CP-OFDM conveying the same data rate provided that a small out-of-band power proportion is required. When a sufficiently small precoding rate is adopted, the SP-NG-OFDM receiver, using guard removal and LMMSE-FDE, is also shown to counteract ICI effectively and exploit frequency diversity over dispersive channels.