A spectral efficient decode-and-forward relaying scheme for satellite broadcast networks

This paper presents a novel spectrally efficient relaying scheme for satellite broadcast networks, where two selective decode-and-forward (SDF) relays are employed to improve the performance of satellite-to-destination link. In the proposed scheme, the satellite continuously transmits the signal through an allocated satellite frequency-band. The relaying stations operate in the half-duplex mode, and share the same frequency band with the satellite to improve the spectral efficiency. A log-likelihood detector is employed at both relays and the destination to conduct joint signal detection and co-channel interference cancellation. Computer simulations are carried out to compare the proposed scheme with the conventional orthogonal-relaying scheme in various channel environments. It is shown that the proposed scheme improves by 50% spectral efficiency for loss of 1.5-5 dB in performance at the high-E_b/N_o range (> 15 dB) for the uncoded communication, and for loss of 0.7-1.2 dB in performance at the high-E_b/N_o range (> 12 dB) for the coded case, respectively.