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To cope with an exponentially increasing demand on mobile data traffic in cellular networks, high-capacity WiFi and device-to-device networks can be exploited as a complementary means to offload and reduce the traffic load of cellular networks. This paper proposes a novel cooperative content dissemination strategy for a heterogeneous network consisting of different types of devices, such as WiFi access points (APs), smartphones, and intelligent vehicles. The proposed strategy offloads a significant proportion of data traffic from cellular networks to WiFi or device-to-device networks using ad hoc connections that opportunistically emerge when mobile devices move and meet one another. The strategy is particularly suited for dissemination of delay-tolerant content. Detailed analysis is provided for the content dissemination process in heterogeneous mobile networks adopting the proposed strategy. On this basis, the optimal parameter settings for the content dissemination strategy are discussed. Simulation and numerical results show that the proposed strategy significantly reduces the amount of data traffic for cellular networks while guaranteeing the successful delivery of content. [ABSTRACT FROM AUTHOR]

In this paper, we study the information propagation process in a 1-D mobile ad hoc network formed by vehicles Poissonly distributed on a highway and traveling in the same direction at randomly distributed speeds that are independent between vehicles. Considering a model in which time is divided into time slots of equal length and each vehicle changes its speed at the beginning of each time slot, independent of its speed in other time slots, we derive analytical formulas for the fundamental properties of the information propagation process and the information propagation speed (IPS). Using the formulas, one can straightforwardly study the impact on the IPS of various parameters such as radio range, vehicular traffic density, and time variation of vehicle speed. The accuracy of the results is validated using simulations. The research provides useful guidelines on the design of vehicular ad hoc networks (VANETs). [ABSTRACT FROM PUBLISHER]

In this paper, we study transmission power to secure the connectivity of a network. Instead of requiring all nodes to be connected, we require that only a large fraction (e.g., 95%) be connected, which is called the giant component. We show that, with this slightly relaxed requirement on connectivity, significant energy savings can be achieved for a large-scale network. In particular, we assume that a total of n nodes are randomly independently uniformly distributed in a unit square in R2, that each node has uniform transmission power, and that any two nodes are directly connected if and only if the power that was received by one node from the other node, as determined by the log-normal shadowing model, is larger than or equal to a given threshold. First, we derive an upper bound on the minimum transmission power at which the probability of having a giant component of order above qn for any fixed q Ȇ (0, 1) tends to one as n →∞. Second, we derive a lower bound on the minimum transmission power at which the probability of having a connected network tends to one as n →∞. We then show that the ratio of the aforementioned transmission power that was required for a giant component to the transmission power that was required for a connected network tends to zero as n →∞. This result implies significant energy savings if we require that only most nodes (e.g., 95%) be connected rather than requiring all nodes to be connected. This result is also applicable for any other arbitrary channel model that satisfies certain intuitively reasonable conditions. [ABSTRACT FROM AUTHOR]