## 2 Literature Review  
There are two primary related research areas: (1) the topology control problem; and (2) information dissemination protocols. For the topology control problem, there are two major categories for the topology control solutions: Cluster-based topology control and distributed topology control. A large variety of approaches for _ad hoc_ clustering have been proposed in the literature [13; 14; 15; 16; 17; 18]. Most of these design approaches are heuristic protocols in which each sensor must maintain knowledge of the complete network or identify a subset of sensors with a clusterhead to partition the network into clusters in heuristic ways. The authors in [13] present a novel cluster-based network topology discovery approach for VANETs by applying a cluster formation procedure similar to the one used in the max-min _d_-hop heuristic approach [14] and utilizes the advantage of a _d_-hop cluster architecture to improve the network topology scalability. However, clusters are formed heuristically without taking the cluster size and their mobility pattern into consideration. [PERSON] _et al._[15] propose a new clustering metric and a clustering algorithm with multi-homing support. It relies only on the vehicle's ability to send and receive wireless packets, which identify the vehicle relationship. Clusters are created with redundant connections between nodes to increase the communication reliability in case of topological changes. Nonetheless, this protocol design leads to high communication overheads. In [16], a clustering technique suitable for the VANET environment on highways is proposed for enhancing the stability of the network topology. This technique takes the speed difference as a parameter to create a relatively stable cluster structure. Note that the traffic pattern is limited to the roads with an uninterrupted flow of traffic. Our previous work [17] focuses on cluster-based topology management of nodes with \"low\" or \"moderate\" mobility. The mobile nodes use random timers to form clusters, including cluster heads, cluster members and gateways, in a distributed way. However, the above control scheme may not work for the nodes with high mobility (e.g., vehicles) in a highly dynamic topology. For distributed topology control, the authors in [8] propose a cone-based distributed topology-control (CBTC) algorithm with directional information and without GPS information. The authors show that taking the cone angle \(\alpha=5/6\pi\) is a necessary and sufficient condition to guarantee that network connectivity is preserved. Even though a set of refinements are further proposed to reduce power consumption and prove that they retain network connectivity, dynamic reconfiguration and complex optimizations are required to maintain the network operations. In [9], the authors utilize the geometric model in which the threshold is determined by the Euclidean distance \(D_{uv}\) between vehicle \(u\) and vehicle \(v\). The threshold is taken to be \(D_{uv}\cdot\alpha\), where \(\alpha\) is the attenuation constant associated with path loss [19]. It is assumed that each node moves at its own constant rate and direction throughout the time interval, such that the lifetime of a mobile network may be sliced into unit time intervals. Accordingly, the topology control problem for each unit time interval is investigated. Although the network is movement-connected throughout the unit time interval, the implementation complexity for solving the topology stability problem is high. Comprehensive surveys of recently proposed topology control algorithms for mobile _ad hoc_ and sensor networks can be found in [20; 21; 22]. For the information dissemination problem, several VSN routing protocols have been proposed for inter-vehicle communication in recent years. Topology-based and position-based routing are two possible strategies of data forwarding commonly adopted for multi-hop wireless networks [23; 24]. Topology-based protocols use the information of available network links for packet transmission.