Cooperative transmission with continuous phase modulation and phase-only forward relays

We propose in the thesis the concept of Phase-Only Forward (PF) as a possible relay strategy for cooperative communication involving CPFSK and GMSK modulations. The technique enables the relay nodes to maintain constant envelop signaling without the need to perform decoding and signal regeneration. The bit-error-probability (BEP) of this PF scheme in a time-selective Rayleigh fading environment, with noncoherent discriminator detection, was analyzed. Both cases of with and without antenna selection at the relay were considered. In the former case, a clever phase-adjustment scheme that allows the relay to maintain phase continuity at the antenna switching instants was proposed. From the performance analysis it can be concluded that PF is a cost-effective alternative to AF and DF, since we no longer need signal regeneration nor expensive linear amplifiers at the relays to support non-constant envelop transmission.