Packet Position Modulation: A Technique for Enhancing Information Transfer Capacity in Ultra-low Duty Cycle Networks

Abstract

This paper presents a data packet position modulation (DPPM) paradigm to enhance information transfer capacity of communication links used by energy-constrained devices. Packet transmissions in low duty cycle networks are often scheduled as TDMA slots, whose periodicity is determined based on application sampling requirements and the energy inflow, often in the form of energy harvesting. The key idea of DPPM is to modulate the inter-packet spacing for coding additional information without incurring additional transmission energy expenditures. This paper presents a DPPM based solution for single-hop transmit-only networks in which a number of low-energy nodes transmit data to an aggregator. The architecture is first developed for a two-node point-to-point link, followed by a multipoint-to-point multiaccess network. Detailed analytical and simulation models are developed to demonstrate the performance of a symmetric and an asymmetric version DPPM. It is shown that by carefully choosing the protocol parameters, DPPM can enhance the effective information transfer capacity of an ultra-low duty cycle network by up to 65% in certain scenarios.