Much attention has been paid to WSNs due to their capability of serving a variety of purposes. Time synchronization is a significant factor in WSNs, and a number of fundamental operations, such as data fusion, power management, and transmission scheduling, require accurate time synchronization. Since the conventional time synchronization protocol for the Internet cannot be directly applied to WSNs, a number of synchronization protocols have been proposed to meet the unique requirements of sensor network applications.

The importance of time synchronization also comes from the evolution of WSNs which has been driven by technological advances in diverse areas. For instance, unlike the currently deployed WSNs, the next generation of sensor networks may consist of dynamic mobile sensors or a mixture of static and dynamic sensors. In this scenario, far more sophisticated time synchronization protocols that efficiently deal with the mobility of sensors will be required. Indeed, as the sensor network becomes more complicated, the role of time synchronization will become much more important.

In this book, the basic features and theoretical background of the time synchronization problem in WSNs were introduced and then the basic approaches were analyzed and compared to reveal the general ideas and features of time synchronization protocols in WSNs. In addition, a survey of existing time synchronization protocols in the literature was provided including the most recent results.

As a main feature of this book, the problem of time synchronization was studied from a statistical signal processing point of view. This book targeted the clock synchronization problem in a general sender–receiver and receiver–receiver timing packet exchange scenario.