Patrachart Komolkiti

Game-based analysis of eavesdropping defense strategy in WMN with directional antenna

This paper is concerned with the framework for finding the optimal stochastic routing to defend intelligent eavesdropping attacks in the Wireless Mesh Network (WMN) with a cone-based, directional antenna. A game-theoretical model is used to find the best strategy to maximize the expected number of secure sessions (ES) under the most severe circumstance. In particular, the WMN has been modeled by the two-person constant-sum game with two players, namely, a network defender and a network eavesdropper. Numerical results show that the enhancement of antenna directionality by decreasing the beamwidth can help improve ESS only in the sufficiently large network case of downlink. In addition, the optimal defending strategy at the proposed game equilibrium has been found to give a better ESS improvement in the downlink case than in the uplink case.

CTM-based evaluation for heterogeneous wireless network selection strategy

In this paper, an analytical framework has been proposed for performance evaluation of heterogeneous wireless network selection strategy. Its analysability is herein derived from the basis of a well established macroscopic model, called cell transmission model (CTM). With this approach, traffic sources have been modelled as deterministic fluid flow of moving users travelling on their vehicles along a road. In contrast to the approaches with microsopic user mobility model often used in the past, user individuality has been well hidden by the proposed framework. The proposed framework has consequently its inherent advantage of computability. Therefore, it is well suited for further extension towards the adaptive optimisation of heterogeneous wireless network selection strategies. In this regard, numerical results have been given on a simple 1-dimensional road network settings with choices of moving users in making their connections via micro and macro cells in both direct and ad hoc modes.

Cooperative and non-cooperative power control games in downlink cognitive radio network with primary user protection

In cognitive radio network, transmission power must be carefully controlled to maximize the channel usage. This paper investigates the relationship of transmission power among primary and secondary users under the game theory framework. Both cooperative and non-cooperative games are considered. Particularly, two variations of cooperative games are formulated, differed by the total utility functions. In all cases, QoS protection of the primary users is embedded in the utility functions. The results show the existence of Nash equilibrium in each case, as well as the trade-off among the total capacity, power consumption, and fairness.

Game theoretic analysis of jamming attack in wireless mesh network with delay tolerance

This paper proposes a framework for studying the impact of a smart attacker in a wireless mesh network that is used to provide delay-tolerant internet connectivity. Non-cooperative game theory is used to define the defending player strategy in terms of network tree routing as well as the attacking player strategy in terms of the varying position of communication signal jammer. To evaluate the game value, the payoff is captured by the expected number of backlogged packets, based on the assumption of network of M/M/1 queues. This game is solved by the well-known method of successive average. And a preliminary experimental result has been reported on a small 2×2 grid network. The finding sheds insights on three scenarios reflecting different intelligence levels inherited by the attacker and the defender in comparison with the equivalent settings without the attacker. Finally, future work worth investigating has been given.

Impact Analysis of Start-Up Lost Time at Major Intersections on Sathorn Road Using a Synchro Optimization and a Microscopic SUMO Traffic Simulation

Start-up lost time is the time lost in the starting of the green time interval when a traffic signal phase changes from red to green and previously stopped vehicles in the curb line queue need time to accelerate to the desired speed. Actual traffic data analytics from newly installed loop coil detectors at all approaching upstream road segments of major intersections on Sathorn Road in Bangkok, Thailand, are used to confirm that the vehicle flow is obstructed considerably by the large start-up lost time. In this paper, the effect of a large start-up lost time is evaluated in terms of the travel time of passenger cars in a calibrated microscopic traffic simulation. The evaluation is based on the simulation of the urban mobility platform, while the traffic signal lights at major intersections are based on the standard Synchro optimization software. By the simulation, the average travel time per vehicle increases from 4% to 37% when the start-up lost time is varied from a baseline value of 1 s to the maximum value of 15 s, which potentially occurred in the actual traffic data collection in this paper. In addition, the optimal traffic signal green phase lengths increase from 2% to 42%, depending on the volume-to-capacity ratio. The similar increasing trend of optimal green time and average travel time per vehicle is observed using theoretical analysis based on M/M/1 and D/D/1 queues to support the results from Synchro. Findings of this paper are beneficial for understanding the impact of start-up lost time at signalized intersections.

Counter-intuitive channel allocation improvement in distributed cognitive radio networks by adding optimal interference in user's utility

Cognitive Radio Network (CRN) is a promising wireless communication solution whereby radio resources are automatically varied to optimize performance in the changing wireless environment. Our work focuses on distributed CRN with rational and independent users. The eventual state often reached in such a system is Nash Equilibrium (NE); multiple NEs with different performance exists. In this paper we segregate the data; individual users-throughput and interference received, at maximum total throughput and different grades of NE. Based on the characteristics of these metrics we develop policies for individual users which are implemented through their utility functions. Counter-intuitive policy is inferred and implemented; adding optimal amount of interference received by a user in its utility enhances the CRN performance measured in the form of normalized cumulative total throughput. At the optimal addition the CRN performance increases by 23% which is illustrated by the simulation results obtained from an average of 1,000 random scenarios.

Performance measurement of maritime ad hoc network testbed in realistic offshore scenario

This work intends to investigate the impact of transmissions between shore and sea, referred to as offshore, using IEEE 802.11 operating in ISM band, in maritime ad hoc networks. Measurements involving offshore transmissions are carried out in the gulf of Thailand. Results are shown in terms of the received signal strength and throughput at various distances. Particularly, the received signal strength agrees with the log-distance path loss model. The parameters are then estimated. The results are also compared with the measurements from an onshore scenario. The outcome of this work can be useful for simulation models to obtain more accurate results in maritime scenarios.

Scheduling rate computing parallelisation in WMN routing game with signal jammer and user priority

This paper is concerned with the study of packet scheduling rate assignment in a wireless mesh network (WMN) with priority-based users under signal jamming attacks. The situation of network router fighting against a malicious signal jammer is formulated as a two-player, non-cooperative game. Parallel computing is introduced to deal with the resultantly large game strategy sets as well as to find empirically the proper scheduling rate assignment. Based on the reported experimental results, the speed-up of algorithmic execution has been confirmed with the computational time savings proportional up to the number of parallel computing workers employed in the cluster machine. Interesting effects of various packet scheduling rates have then been highlighted to evaluate the expected number of backlogged packets in WMN with grid-style topologies and multiple gateways.

Capacity and Fairness Analysis of Game Theoretic Power Controlled Wireless Access Network

In wireless networks, transmission power has adverse effects. With low transmission power, the received signal may be eclipsed by the noise and interference from other transmitters, resulting in low SINR. On the other hand, with high transmission power, the interference seen at other receivers could be too large, also resulting in low SINR. This paper aims to address this problem by using the game theory. Particularly, the scenario of wireless access network with two transmitters, each with two intended receivers, is considered. Selection of transmission power of the two transmitters is modeled as the two-person game, which would lead to a Nash Equilibrium in a non-cooperative scenario. However, with a proper power control, the scenario can become a cooperative game, with a possibility of operating at a Pareto optimum. Three utility functions are investigated, and the trade-off between capacity and fairness is analyzed.

Per-Hop Condition for Optimal End-to-End Capacity of 1-Dimensional Wireless Ad Hoc Networks

The aim of this paper is to disclose the physical constraints that govern the capacity of the multi-hop ad hoc communications in homogeneous interference environment. Based on the Shannon capacity theorem, the end-to-end capacity is analytically derived. The final result is shown as the optimal per-hop condition, a criterion in choosing relay nodes that maximize the end-to-end capacity. Particularly, it has been here found that the optimal next-hop node can be solely determined by the local information of SINR, independent of the distance to reach final destinations. The results can provide valuable insights to WMN relay placement design and wireless ad hoc routing protocols for bandwidth-sensitive applications.