Blockage Mitigation Techniques for On-the-Move Satellite Communications

During Phase 1, we designed and simulated the Spatially Redundant (SPRED) link layer protocol to overcome the problems caused by blockage in satellite on the move communication systems. Our objective during Phase 2 is to test, validate, and demonstrate the operation of the protocol on prototype hardware. The link layer protocol provides reliable and efficient communication services by overcoming the problems associated with blockage by terrain obstacles. The protocol addresses both voice and data communication. The protocol combines standard communications protocol techniques, such as forward error correction, selective acknowledgements, and repeat request retransmission with a novel fast switching algorithm to provide nearly seamless connectivity to a small cadre of cooperating satellite terminals. A military convoy equipped with several satellite communication vehicles would form such a cadre. By rapidly switching which terminal in the cadre is in active use, the protocol avoids the blockages and provides high capacity and reliability to the entire convoy. Validation of the algorithms, protocols, and actual software is necessary in advance of incorporation into satellite terminal designs and fabrication in Phase 3, both to avoid costly mistakes and to attract financing for such an endeavor. We test the system for correct operation, delivery latency, capacity, and reliability.