Wireless Sensor Networks in Residential Layouts

In recent years, Wireless Sensor Networks (WSNs) have gathered a lot of attention as an important research domain. A typical WSN is a multi-hop wireless network consisting of small sensor devices that are capable of sensing, processing (computing), and communicating. These devices sense the environment (temperature, pressure, vibration, acoustics, etc.), process the sensed data often in a distributed fashion, and wirelessly communicates the outcome of processing to a base station. Figure 1 shows a diminutive exemplar of a typical WSN. The viability of WSNs is entirely depends on the small physical size and low cost of the sensor devices. Consequently, sensor devices are severely constrained by the resources. A typical sensor node is built of a 8-bit microcontroller, 4-16 MHz crystal oscillator, few hundred Kbytes of program memory, 4-10 Kbytes of data memory (RAM), radio-chip with data rates between 10-250 Kbps, typically a 10-bit ADC, and two AA batteries. Because of these constraints, even simple protocols and algorithms may not perform to the expectation when actually implemented on the sensor devices − this is the major challenge driving all the current research in WSNs.