Receiver Harvests 21-Hz Clock Signal From GSM Band
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).
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.
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.
