Receiver Harvests 21-Hz Clock Signal From GSM Band

July 30, 2013

To conserve energy in wireless sensor networks, the wake-up receiver can harvest a digital clock signal from an existing wireless standard (i.e., a clock-harvesting receiver).

Nancy Friedrich

With the growing popularity of environmental, health-monitoring, and infrastructure applications, wireless sensor networks are being deployed ever-more widely. Low power consumption is, of course, critical to these applications. To conserve energy, one approach is to replace the accurate on-node timer for an always-on wake-up receiver. Such receivers allow the wireless sensor network to operate in a low-power sleep mode. Here, a wireless signal is used to awaken the nodes. At the University of Michigan, Jonathan Brown and David Wentzloff have taken this approach one step further with their clock-harvesting receiver (CRX).

This receiver extracts a 21-Hz clock signal, which is embedded within the GSM standard, for the wake-up of a wireless sensor network. As a result, it does not have to generate that clock within the network. To reduce the energy required for network synchronization, the receiver was designed for heavily duty-cycled operation in a tiered synchronization strategy. It boasts sensitivity of -87 dBm with 57 μs of jitter while consuming just 126 μW power. In sleep mode, the receiver consumes just 81 pW. See “A GSM-Based Clock-Harvesting Receiver with -87 dBm Sensitivity for Sensor Network Wake-Up,” IEEE Journal Of Solid-State Circuits, March 2013, p. 661.

About the Author

Nancy Friedrich | RF Product Marketing Manager for Aerospace Defense, Keysight Technologies

Nancy Friedrich is RF Product Marketing Manager for Aerospace Defense at Keysight Technologies. Nancy Friedrich started a career in engineering media about two decades ago with a stint editing copy and writing news for Electronic Design. A few years later, she began writing full time as technology editor at Wireless Systems Design. In 2005, Nancy was named editor-in-chief of Microwaves & RF, a position she held (along with other positions as group content head) until 2018. Nancy then moved to a position at UBM, where she was editor-in-chief of Design News and content director for tradeshows including DesignCon, ESC, and the Smart Manufacturing shows.