Wireless communication in a network of mobile devices is a challenging and resource-demanding task, due to the highly dynamic network topology and the wireless channel randomness. This paper investigates information broadcast schemes in 2-D mobile ad hoc networks where nodes are initially randomly distributed and then move following a random direction mobility model. Based on an in-depth analysis of the popular susceptible-infectious-recovered epidemic broadcast scheme, this paper proposes a novel energy and bandwidth-efficient broadcast scheme, named the energy-efficient broadcast scheme, which is able to adapt to fast-changing network topology and channel randomness. Analytical results are provided to characterize the performance of the proposed scheme, including the fraction of nodes that can receive the information and the delay of the information dissemination process. The accuracy of analytical results is verified using simulations driven by both the random direction mobility model and a real-world trace.
@cite_19: Energy efficiency has gained its significance when service providers' operational costs burden with the rapidly growing data traffic demand in cellular networks. In this paper, we propose an energy efficiency model for Poisson-Voronoi tessellation (PVT) cellular networks considering spatial distributions of traffic load and power consumption. The spatial distributions of traffic load and power consumption are derived for a typical PVT cell, and can be directly extended to the whole PVT cellular network based on the Palm theory. Furthermore, the energy efficiency of PVT cellular networks is evaluated by taking into account traffic load characteristics, wireless channel effects and interference. Both numerical and Monte Carlo simulations are conducted to evaluate the performance of the energy efficiency model in PVT cellular networks. These simulation results demonstrate that there exist maximal limits for energy efficiency in PVT cellular networks for given wireless channel conditions and user intensity in a cell.
@cite_5: Unpredictable node mobility, low node density, and lack of global information make it challenging to achieve effective data forwarding in Delay-Tolerant Networks (DTNs). Most of the current data forwarding schemes choose the nodes with the best cumulative capability of contacting others as relays to carry and forward data, but these nodes may not be the best relay choices within a short time period due to the heterogeneity of transient node contact characteristics. In this paper, we propose a novel approach to improve the performance of data forwarding with a short time constraint in DTNs by exploiting the transient social contact patterns. These patterns represent the transient characteristics of contact distribution, network connectivity and social community structure in DTNs, and we provide analytical formulations on these patterns based on experimental studies of realistic DTN traces. We then propose appropriate forwarding metrics based on these patterns to improve the effectiveness of data forwarding. When applied to various data forwarding strategies, our proposed forwarding metrics achieve much better performance compared to existing schemes with similar forwarding cost.
@cite_16: Gossip protocols have emerged as a powerful technique for implementing highly scalable and robust services, such as information dissemination and aggregation. The fact that gossip protocols require very little or no structure to operate makes them particularly appealing to apply in dynamic systems, where topology changes are common (for instance, due to frequent faults or high churn rates). Therefore, gossip protocols seem particularly well fit to operate in wireless self-organizing networks. Unfortunately, these networks have a number of characteristics that impede the deployment of gossip protocols designed for wired networks. In this work we identify the inherent differences in communication between wired and wireless networks and their impact on the design and implementation of gossip protocols. In particular, our comparison includes drawing a distinction between the gossiping primitives suitable for each of these environments. In the context of this analysis, we conclude by presenting a list of open research questions.
There are other broadcast schemes for MANETs beside epidemic schemes. In @cite_16 , reviewed some gossip-based algorithms that can be suitable candidates for information dissemination in MANETs. They pointed out that the design of energy and bandwidth efficient information dissemination schemes for MANETs is a challenging and open problem. A recent work @cite_5 of proposed a novel data forwarding strategy which exploits the transient social contact patterns in social networks. They identified that the low nodal density and the lack of global information are two major challenges in effective data forwarding in delay tolerant networks. We further note that in @cite_19 , Xiang and first proposed an energy efficiency model for wireless cellular networks, and on that basis built an analytical relationship among the wireless traffic, wireless channel model and the energy efficiency. Their work suggested that the energy efficiency optimization of wireless networks should consider the wireless channel randomness. In this paper, these challenges are tackled by introducing a distributed energy-efficient broadcast scheme taking into account channel randomness.