Link Stability Metrics Research Articles

Collaborative caching relay algorithm based on recursive deep reinforcement learning in mobile vehicle edge network

With the rapid development of Internet of vehicles (IoV) and the continuous emergence of vehicle information applications, the demand for content in vehicle networking is growing at an alarming speed. Mobile vehicular edge caching is regarded as a promising technology in improving Quality of Service (QoS) and reducing latency. Many caching algorithms have been proposed, which usually place contents in the Road Side Units (RSUs) to provide services to users near them. However, due to the high-speed movement of vehicles and limitations of RSU coverage, caching interrupts often occur frequently, leading to a deterioration in service quality. To deal with this problem, we make full use of Vehicle-to-Vehicle (V2V) collaboration to construct a caching system which does not require RSU support, and propose a Recursive Deep Reinforcement Learning based Collaborative Caching Relay strategy (RDRL-CR). On purpose to minimize the service delay under capacity constraints, the caching problem is formulated as an integer linear programming problem, and caching decisions are achieved through partially observable Markov Decision Process (MDP). Specifically, this strategy utilizes a Graph Neural Network (GNN) to predict vehicle trajectories, and then selects vehicles that can serve as caching nodes by calculating link stability metrics between vehicles. The Long Short Term Memory (LSTM) network is embedded into a deep deterministic strategy gradient algorithm to achieve the final caching decision. Compared with existing caching strategies, the proposed caching strategy in this paper improves the caching hit rate by about 25% and reduces content access latency by about 20%.

Novel strategies for path stability estimation under topology change using Hello messaging in MANETs

Path stability estimation due to connectivity failures is one of the key challenges for effective communication under random mobility of network nodes in mobile ad hoc networks (MANETs). Under random movement of network nodes and topology triggered reactive path distribution statistics among the neighboring nodes, there must be a unified model to determine an adequate path stability estimation strategy in MANETs. We present novel link connectivity metrics (LCM) and path distribution analysis (PDA) strategies for path stability estimation under uniform speed and random trajectory of mobile nodes. We also design an adaptive routing model that guarantees effective communication among neighboring nodes inside a cluster. We find that LCM strategy among neighboring nodes is affected by the link expiration time, relative velocity, link connectivity, and link stability metrics in terms of remaining probability for a connected link, link recovery probability, and stability of a path at different time steps of a Markov process. We also find that PDA strategy among neighboring nodes is affected by the link excess life, distribution of path durations, cluster stability, and path duration statistics in terms of throughput and overhead during Hello message(s) communication at different time steps of a Markov process. Analytical and simulation results indicate efficacy of the proposed LCM and PDA strategies by efficiently estimating path stability under topology change, thereby, increasing the global network connectivity.

Moralism: mobility prediction with link stability based multicast routing protocol in MANETs

In recent research, link stability is getting tremendous attention in mobile adhoc networks (MANETs), because of several impediments that occur in a reliable and robust network. Link stability metric is used to improve network performance in terms of end-to-end delay, data success delivery ratio (DSDR) and available route time (ART). Energy consumption, bandwidth and communication delay of major concern in ad hoc networks. A high mobility of MANET nodes reduces the reliability of network communication. In a dynamic networks, high mobility of the nodes makes it very difficult to predict the dynamic routing topology and hence cause route/link failures. Multicast in MANETs is an emerging trend that effectively improves the performance while lowering the energy consumption and bandwidth usage. Multicast routing protocol transmits a packet to multicast a group at a given time instant to achieve a better utilization of resources. In this paper, node mobility is considered to map better their movement in the network. So, the links with long active duration time can be identified as a stable link for route construction. Variation in signal strength is used to identify whether the direction of the node is towards or away from estimating node. We consider signal strength as QoS metric to calculate link stability for route construction. Efforts are made to identify the link with highly probable longer lifetime as the best suitable link between two consecutive nodes. We predict the movement time of nodes that define the route path to the node destination. Exata/cyber simulator is used for network simulation. The simulation results of the proposed routing protocol are compared with on-demand multicast routing protocol and E-ODMRP, which works on minimum hop count path. Analysis of our simulation results has shown improvement of various routing performance metrics such as DSDR, ART, routing overhead and packet drop ratio.

Link-stability and Energy Aware Multipath Routing in MANET

Energy conservation is important for mobile ad hoc networks where devices are expected to work for longer periods of time without the need for charging their batteries. Therefore there is a need of an intelligent routing protocol that can minimize overhead and ensure the use of minimum energy routes. In Progressive Energy Efficient Routing, energy efficient shortest paths are selected with minimum energy consumption. Here due to the single path routing, there occur end-to-end delay, routing overhead and packet loss. Therefore to overcome these issues, PEER can be extended for multipath routing. Link-stability metrics and energy aware metrics can be applied for path selection. By this method, stable links are selected. In this study, energy efficient routing is done with maximum life time. The proposed Link-Stability and Energy Aware Multipath Routing gives good performance results in terms of packet delivery ratio, packet drop, energy consumption and delay compared with Progressive Energy Efficient Routing.

Mobility Metrics Evaluation for Self-Adaptive Protocols

Cross-layer mechanism, for which a protocol locating at a given layer uses information issued from other layers, may enhance the mobile networks performance. Some of those mechanisms are based on mobility metrics. For example, the establishment of a route by choosing less mobile nodes could improve the routing protocol. In this paper, we study the ability of mobility metrics to reflect the mobility influence over the protocol performances. The proposed approach evaluates the ability of a metric from its capacity to indicate or predict the routing protocol performance. Three routing protocols are considered: AODV, DSR and OLSR. The studied mobility metrics are Frequency of Link State Changes (LC), Link Connectivity Duration (LD) and Link Stability Metric (LS). The metrics are evaluated by simulation, firstly in a general case then in a scenario case.