Abstract—In Content-Based Mobile Ad-hoc Networks (CB-MANETs), random linear Network Coding (NC) can be used to efficiently and reliably disseminate large files under intermittent connectivity. Conventional NC involves unrestricted re-encoding at intermediate nodes, and consequently is vulnerable to pollution attacks. To avoid pollution attacks, the most computationally- and energy- efficient approach is to restrict the encoding at the source. However, source restricted encoding generally reduces the robustness of the code in the face of errors, losses and mobility induced intermittence. CB-MANETs introduce a new option. In CB-MANET, intermediate nodes can cache a file and exploit their processing power, storage space, and content awareness to forward the cached file with their own signature after the file is fully reassembled in their caches as if they were new sources for that file. Thus, NC packets can be encoded not only at the originator but also at the intermediate caches while still providing full protection from pollution. In fact, this approach, which is referred to as full cache coding, allows us to identify polluters by examining their signatures. The hypothesis we wish to test in this paper is whether in CB-MANETs with pervasive caching, coding restricted to full caches can perform as well as unrestricted coding. In the paper, we examine and compare unrestricted coding to full cache coding, source only coding, and no coding. Our results show that full cache coding performs almost as well as unrestricted coding while maintaining full protection against pollution attacks.

Index Terms—MANET, content-based, network coding

Cite: Joshua Joy, Yu-Ting Yu, Victor Perez, Dennis Lu, and Mario Gerla, "A New Approach to Coding in Content-Based MANETs," Journal of Communications, vol. 9, no. 8, pp. 588-596, 2014. Doi: 10.12720/jcm.9.8.588-596