Table of contents
1. Introduction……….. 1
2. Sensor Networks ………. 4
2.1. What is a sensor networks………. 5
2.2. WSNs and traditional ah-hoc networks……… 6
2.3. Applications……….. 6
2.4. Issues………. 11
2.5. Architectural Layer Model……… 14
3. The Berkeley motes environment ………... 17
3.1. Hardware………... 17 3.1.1. Overview……… 17 3.1.2. Processor……… 19 3.1.3. Leds……… 20 3.1.4. Flash Memory……… 20 3.1.5. Radio……….. 21 3.1.6. Sensing Hardware……….. 23 3.2. Software……… 27 3.2.1. Traditional OS architectures……….. 27 3.2.2. Introduction to TinyOS……….. 27 3.2.3. TinyOS design……… 29 3.2.4. Communication……….. 32 3.2.5. Active Message……….. 34 3.2.6. nesC……… 36 3.2.7. TinyOS application……… 39
4. Measurements ………. 52 4.1. Performance indices……….. 52 4.2. Test modality……… 53 4.3. Transmission Range……….. 54 4.4. Power Consumption………...……... 68 4.5. Throughput……… 76
4.6. Software overhead and time analysis……… 81
5. System Model ………. 86
6. Conclusion ………...………... 89
7. Appendix ………...……….. 91
7.1. Indoor Tests………...………... 91
7.2. Rayleigh Fading………...………. 92
7.3. Minimum horizontal distance………...……… 95
7.4. Rain…...……… 96
7.5. Fog………...………. 97
7.6. Height from ground………... 98
7.7. Random antenna disposition………...……….. 100
7.8. Power consumption………... 101
