Summarization: Environmental sensing applications require dense sensor deployments for precise monitoring of each plants' micro-climate; For such applications, scatter radio is a promising communication and networking technology. Since modulation is achieved by means of reflection, very low-cost and low-power RF front-ends and sensor nodes can be constructed. However, such technology has demonstrated limited range in commercial scatter radio applications, like radio frequency identification (RFID) systems. In order to alleviate that problem, the bistatic architecture has been proposed, where emitter of illuminating carrier towards the tag/sensor and reader of the modulated reflection (from tag/sensor) are dislocated. Also, frequency shift keying (FSK) modulation has been utilized for simultaneous transmission of many scatter radio sensors, through frequency division multiple access (FDMA). These schemes allow the creation of a scatter sensor network, using flexible topologies with multiple emitters and a single reader, increasing the probability for short emitter-to-tag/sensor distances. This work experimentally demonstrates the creation of such scatter radio network with low-cost 8051 micro-controller units (MCU), where sensed information is converted to digital messages using the internals analog-to-digital (ADC) converters. Furthermore, implementation of short-block length channel encoding based on Reed-Muller codes are tested experimentally. This work is a small step towards the realization of large-scale, scatter radio sensor networks.

Undergraduate Thesis, ECE Department TUC