Multi Objective Superposition Coding for Reliable Networks

Single objective optimization in physical layer design (maximizing rate or maximizing reliability) can potentially reduce overall network throughput. The major challenge here is to find a way to achieve a stable and reliable link without sacrificing the available channel capacity. Superposition coding with two rates allows the transmitter to superimpose a high rate and a low rate massages with different protection criteria against channel error. This naturally allows the physical layer designer to follow a multi-objective optimization strategy by providing a stable and reliable link in low rate portion of the signal and a high capacity link in high data rate portion of the signal. In fact, by using superposition coding, packets with high priority and network control packets can be encoded within the reliable portion of the superimposed signal while the less sensitive, more error tolerant data such as multimedia packets can be sent through high data rate portion of the signal. Building on the success of our Phase I results, in Phase II of this project we plan to build superposition coding transceiver on an FPGA and design a network MAC and routing protocol that exploits the superposition coding physical layer in high dynamic SNR environment. BENEFIT: The first planned product from the proposed effort will include: 1) FPGA based superposition coding transceivers; 2) superposition-aware MAC and routing protocols that take advantage of the benefits from superposition coding; and 3) a comprehensive wireless evaluation environment that can integrate simulation, hardware emulator, and hardware-in-the-loop capabilities. Put together, they form a generic toolset prototype for military as well as researchers in the networking community to investigate how to leverage superposition coding (and other related physical layer technologies) in providing more reliable wireless networking solutions, which is of critical importance for dynamic wireless networks such as Airborne Networks.