Treffer: UCC : Update-conscious compilation for energy efficiency in wireless sensor networks

Wireless sensor networks (WSN), composed of a large number of low-cost, battery-powered sensors, have recently emerged as promising computing platforms for many non-traditional applications. The preloaded code on remote sensors often needs to be updated after deployment in order for the WSN to adapt to the changing demands from the users. Post-deployment code dissemination is challenging as the data are transmitted via battery-powered wireless communication. Recent studies show that the energy for sending a single bit is about the same as executing 1000 instructions in a WSN. Therefore it is important to achieve energy efficiency in code dissemination. In this paper, we propose novel update-conscious compilation (UCC) techniques for energy-efficient code dissemination in WSNs. An update-conscious compiler, when compiling the modified code, includes the compilation decisions that were made when generating the old binary. The compiler employs a detailed energy model and strives to match the old decisions for a more energy-efficient result. In most cases, matching the previous decisions improves the binary code similarity, reduces the amount of data to be transmitted to remote sensors, and thus, consumes less energy. In this paper, we develop update-conscious register allocation and data layout algorithms. Our experimental results show that they can achieve great improvements over the traditional, update-oblivious approaches.