Frequency Packing and Multiuser Detection for CPMs: How to Improve the Spectral Efficiency of DVB-RCS2 Systems

• We consider a frequency division multiplexed systemwhere each user adopts a continuous phase modulation (CPM)and multiuser detection is employed at the receiver side. Thespectral efficiency (SE) is used as a performance measure tocompare, from an information-theoretic point of view, differentmodulation formats. More precisely, we consider the newCPM formats recently included in the DVB-RCS2 standard.We describe a framework for computing the information rate(IR) and the SE of such systems, and use it for optimizing thechannel spacing between adjacent users and the CPM phaseresponse. Our analysis reveals that modulation formats adoptedin the DVB-RCS2 standard are suboptimal in terms of SE, whileif we allow multiuser detection excellent performance can beachieved by using simple binary formats and highly frequencypacked signals. Furthermore, we consider practical schemes,where CPMs are serially concatenated with an outer code, and alow-complexity multiuser receiver is employed, showing that thetheoretical limits predicted by the IR analysis can be approached.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Kommunikationssystem (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Communication Systems (hsv//eng)

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