Dynamic Slot Allocation Algorithm for R-ALOHA with Priority (PR-ALOHA)

In this work, a new approach for dynamically allocating high priority probability and high priority slots in PR-ALOHA (Reserved ALOHA with Priority) was introduced. The Dynamic Slot Allocation (DSA) algorithm in PR-ALOHA is performed by dynamically allocating the number of high priority slots and high priority probability based on the available traffic. The performance of the system with DSA algorithm was tested by simulation and compared to the performance of the system without DSA. The simulation shows that the proposed DSA algorithm provides an approach to improve performance in a controlled manner for high and low priority traffic. Two functions are proposed for DSA, the first is an exponential growth function, where the numbers of high priority slots increase with the number of terminals until it reach a maximum value. The second is a bell-shaped function where the number of high priority slots increases to a maximum and then decreases. Both functions are tested with fixed high priority probability (hpp) of 25% and dynamic hpp ranging (8%-63%). The bell shaped function provides better performance at fixed hpp, while the exponential function provides better performance with dynamic hpp. The simulation shows that the use of DSA improves the performance of PR-ALOHA.