Wireless personal area networks (WPANs) are used to convey information over relatively short distances. A WPAN may transfer data at a relatively low rate to minimize power consumption. Unlike wireless local area networks (WLANs), WPANs employ little or no infrastructure. Consequently, WPANS allow small, power-efficient, and inexpensive solutions to be implemented for a wide range of devices.
Smart Utility Networks (SUNs) are one application of WPAN technology. A SUN may operate either over short ranges such as in a mesh network where utility meter information is sent from one utility meter to another, or over longer ranges such as in a star topology where utility meter information is sent to a pole-top collection point. The terms WPAN and SUN are used interchangeably herein.
Devices that communicate via a WPAN, or other type of wireless network, include oscillators that determine the carrier frequencies of the network. The frequencies of the oscillators drift over time. The drift can cause frequency and/or phase errors between the oscillators of communicating wireless devices. Such errors can cause errors in symbol decoding due to rotation of the symbol constellation in the receiving device. Some wireless devices may include a phase-locking loop to lock the receiver frequency to the carrier frequency of a transmission.