Modeling data transactions with standard protocols for low power wireless sensor links

The cost of a data transaction measured in terms of energy consumption is very important in wireless sensor networks. The sensors are battery- or solar cell powered, must have long lifetime and must operate reliably under various conditions. Various proprietary hardware and software systems have been developed that optimize the power consumption of a node. However, using standard Protocols requires that the energy consumption of data transactions is well known. We present analytical models of data transactions with standard protocols taking into consideration channel quality and the whole transaction cycle. With these models it is possible to compare transaction costs of different protocols, measure the impact of the channel quality and the sensor cell size on the energy consumption of a sensor. Transactions with Bluetooth and a nonpersistent CSMA protocol are studied in the model framework, which shows that both protocol types can meet requirements of low energy sensor cells.