A DTN System for Nanosatellite-based Sensor Networks using a New ALOHA Multiple Access with Gateway Priority

Abstract

This paper presents and evaluates a new communications architecture to provide services to terrestrial sensor networks using a space delay-tolerant networking (DTN)?based solution. We propose a new multiple access mechanism based on extended unslotted ALOHA that takes into account the priority of gateway traffic, which we call ALOHA multiple access with gateway priority (ALOHAGP). We assume a finite sensor population model and a saturated traffic condition where every sensor always has frames to transmit. The performance was evaluated in terms of effective throughput, delay and system fairness. In addition, a DTN convergence layer (ALOHAGP-CL) has been defined as a subset of the standard TCP-CL (Transmission Control Protocol-Convergence Layer). Through simulations, this paper reveals that ALOHAGP/CL adequately supports the proposed DTN scenario, mainly when reactive fragmentation is used.