ALMA: The Agile Loss Management Approach in Wireless Networks

Tactical military wireless networks present unique challenges. They must provide the capabilities of commercially available wireless networks—under radically different conditions. Nodes are very mobile and network topologies change often. Military networks cannot use commercially available frequencies, which have line-of-sight limitations and are easily detected and jammed. Software defined radios (SDRs) provide new capabilities in which the physical layer can be controlled by software, and the underlying radio characteristics (waveforms) can be easily reconfigured by a software change. The programming of SDR networks, however, often ties higher layer performance to the physical layer characteristics. And inefficient use of the network results in suboptimal performance for both data packets, which require reliable transmission, and voice packets, which require timely transmission. The ALMA protocol will decouple the physical layer from the higher layers, and increase reliability by using redundant transmission paths. These paths occur in any combination of three ways: retransmission, simultaneous transmissions to multiple nodes (which split into multiple paths that converge on the destination), and multiple radio channels. We will demonstrate the feasibility of ALMA by creating the protocol and simulating its performance.