Performance analysis on DPSK modulation using symbol repetition and interleaving

It is well known that the differential phase shift keying (DPSK) transmission does not require a reference phase and reduces the computational complexity and power consumption of the receiver at the cost of the transmission reliability. To improve the reliability of transmission under such scenario, we use a symbol repetition scheme to the DPSK modulation, such as the IEEE 802.15.6 wireless body area network and the ITU-T G.9903. However, the message symbol repetition with interleaving in conventional manner as in coherent modulation schemes may degrade the receiver performance because of the noise characteristic of the differential demodulation structure. In this work, we analyze the performance of repeated DPSK system with and without the interleaver and demonstrate which scenario is suitable for each modulation order. We propose a proper transmission setting, which achieves noticeable performance improvement at the receiver as well as enhances the energy efficiency of the communication system. Since it can be implemented with very small modification to existing systems, our results are highly applicable with negligible modification of the hardware structure and thus enable substantially low-cost implementation in future communication systems including wireless body area network internet of things applications.