GENERAL WAKE-UP RADIO MODULE FOR ISM BAND

Abstract: With the word of smart, the whole world is running on the smart technologies and smart devices which are fairly constructed by wireless sensors networks. The heart of the WSNs are nodes, which are deployed in different environmental conditions with different applications.‘Power constraint’ is a major challenge faced by all manufacturers of nodes, as all the components of the nodes are running just with a single source battery.The work presented in this thesis is an attempt to reduce the power consumption of WSNsby developing a unique Wake-Up Radio system that is super-efficient in power consumption when one compares it to duty cycling method. This paper presents a simple wake-up radio architecture with easily available Off the shelf components and operating in ISM band.At the transmitting end, a receiver with 125 KHz baseband signal is modulated on an 868MHz frequency carrier and is transmitted with the help of homemade dipole antenna. The wake-up radio receiver is constructed with a receiving antenna of 868 MHz and a network that matches good impedance to reduce the power loss of received signal, followed by a demodulation circuit with HSMS-285C zero bias Schottky diode to retrieve the baseband signal and to increase the sensitivity of the device. Later, the retrieved baseband signal is received by AS3933 low frequency wake-up receiver. The AS933 works like a comparator which compares the incoming address with the stored address to generate wake-up interrupt over node’s microcontroller activating it to perform its function.Measurements were made with the help of AS3933 demo board. The proposed system has a current consumption of 42.74μA including the current consumption of the components deployed in the demo board. In an ideal case, wake-up radio can be constructed without usingAS3933 demo board by using only AS3933 IC that gives current consumption of 2.8μA. The developed prototype has a sensitivity of -40 dBm which resulted in a wake-up distance of 20meters at an output power of -5 dBm from the transmitting antenna. This justifies that the proposed system lowers power consumption in wireless sensor networks when compared to duty cycling.