Continuous phase modulation for satellite communications

摘要

A new coded continuous phase modulation (CPM) scheme is proposed to enhance physical layer performance of the current DVB-RCS standard for a satellite communication system. The proposed CPM scheme uses a phase pulse design and combination of modulation parameters to shape the power spectrum of CPM signal in order to improve resilience to adjacent channel interference (ACI). Additionally, it uses a low complexity binary convolutional codes and S-random bit interleaving. Phase response using the proposed CPM scheme is a weighted average of the conventional rectangular and raised-cosine responses and provides optimum response to minimize frame error rate for a given data rate.

主权项

1. A device comprising:
a bit-to-symbol generator operable to generate a symbol stream comprising a plurality of symbols, the symbol stream being based on a source data stream; and a continuous phase modulator operable to modulate the symbol stream, based on a plurality of modulator code parameters, including an alphabet size M indicating a maximum number of transmission symbols, a modulation index h, a pulse width L, a target pulse reflecting a combination of a raised-cosine pulse and a rectangular pulse, a forward error correction (FEC), a code rate R, and a symbol spacing ΔfT, wherein qAV is a continuous phase modulation phase response of the target pulse as a function of time, wherein qRC is a continuous phase modulation phase response of the raised-cosine pulse as a function of time, wherein qRE is a continuous phase modulation phase response of the rectangular pulse as a function of time, and wherein qAV comprises a weighted average combination of qRC and qRE based on respective weighting factors ∝RC and ∝RE, wherein, for a given throughput (bits/sec/Hz), the weighting factor ∝RC is determined to optimize a width of a main lobe for qRC and the weighting factor ∝RE is determined to optimize a level of side lobes for qRE.