On the feasibility of high-power radios in sensor networks

Wireless sensor nodes are constrained by limited energy resources. A significant portion of this limited energy is spent in communication, making energy efficiency of the radio a very important factor in increasing the overall lifetime of a sensor node. An ideal radio, in terms of energy efficiency (ignoring issues of transmission range and delay), should satisfy two requirements. First, it should minimize the energy used per bit when transmitting or receiving. Second, its idle time energy consumption should be minimal. Unfortunately, no such "ideal" radio exists. Current sensor radios (e.g., CC2420) meet the second requirement - the energy consumption in the inactive states is very low in comparison to IEEE 802.11 radios, which are comparatively energy-inefficient due to high switching-on cost and idle state energy consumption. On the other hand, IEEE 802.11 radios perform much better when it comes to energy consumption per bit. So the natural question to ask is whether there exists a way to combine the positive features of these two types of radios leading to increased energy conservation. We argue that this objective can indeed be achieved by adding a high-power IEEE 802.11 radio to the mote platform alongside the already existing sensor radio and managing them by an energy-efficient scheme as proposed in this work.