Noncoherent Digital Network Coding Using Multi-Tone CPFSK Modulation

Digital network coding is a relaying technique that increases throughput in two-way relay networks. In contrast with analog network coding, which relays received analog signals plus noise, digital network coding relays digital code-words. The digital code-words are created by demodulation, channel decoding, and re-encoding at the relay. By using FSK and non-coherent reception, the relay may operate without knowledge of the phases of the signals transmitted by the two source terminals. In this paper, previous work on binary FSK is extended to multi-tone FSK, where the number of tones may be any power of 2. The relay receiver is formulated for any number of tones that is a power of two.