A Space-based Information Port Access Algorithm Based on Enhanced Contention Resolution

• 1、School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876
• 2、School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876
• 3、Communications and Navigation Satellite General Department, China Academy of Space Technology, Beijing 100094

Abstract：When the system load is too high, the existing competitively based random access algorithm is prone to multiple user terminals preempting the same channel resource, resulting in packet collision and reduced channel utilization. Therefore, it cannot be directly applied to the space-based information port system. Aiming at the problem that high dynamic terminals need fast access, this paper proposes an improved ECRA access algorithm based on the enhancing contention resolution Aloha (ECRA) access algorithm. The algorithm takes advantage of the multi-star coverage of the space-based information port system in the communication process of the user terminal, improves the iterative interference cancellation in the ECRA algorithm, and optimizes the system throughput and packet loss rate. On this basis, priority access control is introduced to optimize the success rate of the first access of highly dynamic terminals. The simulation results show that the peak throughput rate of the improved algorithm can reach 1.1bits/symbol, which is better than the 0.7bits/symbol of the ECRA algorithm without considering the power imbalance. The success rate of the first access of the highly dynamic terminal can be maintained at more than 99%, avoiding the problem of the decline of the access success rate of the ECRA algorithm when the data packet arrival rate is too high.

Keywords： space-based information port high dynamic terminal random access