A Random Access Scheme for Satellite Packet Communication with Intentional Interference

We study a random access scheme for satellite packet communication with intentional interference. A modified Slotted ALOHA protocol is used with interferer power sensing to achieve maximum user throughput. For a malicious interferer who ignores the control parameters broadcast by the satellite (such as the back-off parameter), we show that the degradation of channel throughput is inversely proportional to the rate at which the interferer transmits on time slots. Next, we provide a new set of feedback parameters using dynamic estimates of the number of backlogged packets in the system as well as the estimated power of the interferer. We then estimate the transmission rate of the interferer using authentication and observed channel feedback. Finally, we simulate the performance of an ALOHA channel subjected to an interferer using both the original and a modified Rivest algorithm. We show that the unmodified Rivest algorithm performs close to the maximum achievable throughput for most interferer transmission rates despite an increasing overestimation of the number of backlogged packets in the system. We also show that the modified Rivest algorithm achieves slightly higher throughput and a much better estimate of the number of backlogged packets in the system under the same conditions. For the stationary interferer considered, the propagation delay of the channel has little effect on achievable throughput.