A QoS-aware, energy-efficient wireless node architecture

As we enter the post-PC era, we begin to see the proliferation of wireless-connected, battery-operated, multimedia devices distributed throughout our environment. Scaling down the shared-bus personal computer architecture and using it as a template for these devices, even for very thin clients, appears to be the logical "next step" in computer evolution. However, these devices experience a different set of operating constraints and serve a different function than the general purpose PC, indicating the need for a fresh approach. Specifically, a general purpose communication architecture is needed to supplant that of the prevailing general purpose computation device. This paper presents such an architecture with two key enabling features. First, an intra-node router replaces the shared microprocessor bus to enforce the efficient movement of data among task-specific computation elements. Second, a new functional partitioning places link and network layer decision making closer to where it is needed in the common case while still supporting the adaptivity required of a wireless device. Both techniques significantly boost performance, whose benefits may be reaped as either increased throughput, or as is typically more useful in battery-operated devices, improved energy efficiency, Finally, the paper concludes with a description of the wireless adaptive network device (WAND), a printed circuit board constructed to demonstrate these ideas.