Topology Control (TC) is one of the most important techniques used in wireless ad hoc and sensor networks to reduce energy consumption (which is essential to extend the network operational time) and radio interference (with a positive effect on the network traffic carrying capacity). The goal of this technique is to control the topology of the graph representing the communication links between network nodes with the purpose of maintaining some global graph property (e.g., connectivity), while reducing energy consumption and/or interference that are strictly related to the nodes’ transmitting range. In this article, we state several problems related to topology control in wireless ad hoc and sensor networks, and we survey state-of-the-art solutions which have been proposed to tackle them. We also outline several directions for further research which we hope will motivate researchers to undertake additional studies in this field.
The recent emergence of affordable, portable, wireless communication and
computation devices and concomitant advances in the communication infrastructure have resulted in the rapid growth of mobile wireless networks. On one hand, this has led to the exponential growth of cellular networks which are based on the combination of wired and wireless technologies. On the other hand, this has renewed the interest of the scientific and industrial community in the more challenging scenario in which a group of mobile units equipped with radio transceivers communicate without the assistance of any fixed infrastructure.
Networks composed of mobile, untethered units communicating with each other via radio transceivers, typically along multihop paths, have been called ad hoc networks in the literature.1 Ad hoc networks can be used wherever a wired backbone is infeasible and/or economically in convenient, for example, to provide communications during emergencies, special events (expos, concerts, etc.), or in hostile environments. Wireless sensor networks (WSNs) are a special class of ad hoc networks. In a WSN, the interconnected units are battery-operated microsensors, each of which is integrated in a single package with low-power signal processing, computation, and a wireless transceiver. Sensor nodes collect the data of interest (e.g., temperature, pressure, soil makeup, etc.), and transmit them, possibly compressed and/or aggregated with those of neighboring nodes, to the other nodes. In this way, every node in the network acquires a global view of the monitored area that can be accessed by the external user connected to the WSN through one or more gateway nodes. Potential applications of sensor networks abound; they can be used to monitor remote and/or hostile geographical regions, to trace animals movement, to improve weather forecast, and so on. The following aspects that have to be carefully taken into account in the design stage are peculiar to wireless ad hoc networks.

r u doing research on ad hoc or WSN? or r u going to do your graduate design on this topic ：）it helps but except topology control, there are many other things, such as energy control, sleep control, routing protocols etc, needed to concentrate on. i think if you choose WSN as your topic, it is really a challenge :)


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