A crucial factor in numerous Wireless Sensor Networks (WSNs) is the security they provide. A promising approach for providing high-levels of security at a low energy cost is the low-power reconfigurable Complex Programmable Logic Devices (CPLDs). This paper presents a pioneering WSN platform which embeds a CPLD in a standard WSN node. This platform, as our realworld experiments demonstrate, accelerates one of the most widely used authentication algorithms by more than 3000 times. Moreover, the proposed system can accelerate by three orders of magnitude the header checksum calculation scheme that needs high processing power. At the same time the overall energy consumption of the new node is reduced up to to 98%, when compared with the consumption of a standard CPU-based WSN node executing those security algorithms in software.

Abstract:The motivation of this research was to evaluate the main memory performance of a hybrid super computer such as the Convey HC-x, and ascertain how the controller performs in several access scenarios, vis-à-vis hand-coded memory prefetches. Such memory patterns are very useful in stencil computations. The theoretical bandwidth of the memory of the Convey is compared with the results of our measurements. The accurate study of the memory subsystem is particularly useful for users when they are developing their application-specific personality. Experiments were performed to measure the bandwidth between the coprocessor and the memory subsystem. The experiments aimed mainly at measuring the reading access speed of the memory from Application Engines (FPGAs). Different ways of accessing data were used in order to find the most efficient way to access memory. This way was proposed for future work in the Convey HC-x. When performing a series of accesses to memory, non-uniform latencies occur. The Memory Controller of the Convey HC-x in the coprocessor attempts to cover this latency. We measure memory efficiency as a ratio of the number of memory accesses and the number of execution cycles. The result of this measurement converges to one in most cases. In addition, we performed experiments with hand-coded memory accesses. The analysis of the experimental results shows how the memory subsystem and Memory Controllers work. From this work we conclude that the memory controllers do an excellent job, largely because (transparently to the user) they seem to cache large amounts of data, and hence hand-coding is not needed in most situations.