Conference Paper

Dynamic Adaptation of Joint Transmission Power and Contention Window in VANET

Dept. of Electr. & Comput. Eng., Old Dominion Univ., Norfolk, VA, USA
DOI: 10.1109/VETECF.2009.5378793 Conference: Vehicular Technology Conference Fall (VTC 2009-Fall), 2009 IEEE 70th
Source: IEEE Xplore


In this paper, we propose an algorithm for joint adaptation of transmission power and contention window to improve the performance of vehicular network in a cross layer approach. The high mobility of vehicles in vehicular communication results in the change in topology of the Vehicular Ad-hoc Network (VANET) dynamically, and the communication link between two vehicles might remain active only for short duration of time. In order for VANET to make a connection for long time and to mitigate adverse effects due to high and fixed transmission power, the proposed algorithm adapts transmission power dynamically based on estimated local traffic density. In addition to that, the prioritization of messages according to their urgency is performed for timely propagation of high priority messages to the destination region. In this paper, we incorporate the contention based MAC protocol 802.11e enhanced distributed channel access (EDCA) mechanism to implement a priority-based vehicle-to-vehicle (V2V) communication. Simulation results show that the proposed algorithm is successful in getting better throughput with lower average end-to-end delay than the algorithm with static/default parameters.

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    • "It can risk to deliver the Emergency Safety Application (ESA) messages because they are queued when the congestion in channel occurs or message rate reaches its maximum threshold. As the threshold values are used for the density of vehicles and also for the collision in the channel, the protocol proposed in [7] does not seem to be scalable. Anyhow, the simulation results show the lower delays by prioritizing the different type of message and high throughput. "
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    ABSTRACT: In vehicular ad hoc networks, the dynamic change in transmission power is very effective to increase the throughput of the wireless vehicular network and decrease the delay of the message communication between vehicular nodes on the highway. Transmission range is directly proportional to the transmission power the moving node. If the transmission power will be high, the interference increases that can cause higher delay in message reception at receiver end, hence the performance of the network decreased. In this paper, it is analyzed that how transmission power can be controlled by considering other different parameter of the network such as; density, distance between moving nodes, different types of messages dissemination with their priority, selection of an antenna also affects on the transmission power. The dynamic control of transmission power in VANETs serves also for the optimization of the resources where it needs, can be decreased and increased depending on the circumstances of the network. Different applications and events of different types also cause changes in transmission power to enhance the reach-ability. The analysis in this paper is comprised of density, distance with single hop and multi-hop message broadcasting based dynamic transmission power control as well as antenna selection and applications based. Some summarized tables are produced according to the respective parameters of the vehicular network. At the end some valuable observations are made and discussed in detail. This paper concludes with a grand summary of all the protocols discussed in it.
    10/2013; 5(3). DOI:10.5121/ijngn.2013.5301
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    • "Several studies (e.g., [10] and [11]) have illustrated the suitability of IEEE 802.11p for highway applications , and in [12]–[14], proxy vehicles are used to improve RSU utilization and decrease vehicle contention. Vehicle transmitter power control has been used as a mechanism for trading-off network connectivity and reduced interference levels between vehicles (e.g., [9], [15], and [16]). The energy efficiency for VANETs, however, has typically not been an issue as vehicles are usually assumed to have unlimited energy reserves. "
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    ABSTRACT: In this paper we consider the problem of scheduling for energy-efficient roadside infrastructure. In certain scenarios, vehicle locations can be predicted with a high degree of accuracy, and this information can be used to reduce downlink infrastructure-to-vehicle energy communication costs. Offline scheduling results are first presented that provide lower bounds on the energy needed to satisfy arriving vehicular communication requirements. We show that the packet-based scheduling case can be formulated as a generalization of the classical single-machine job scheduling problem with a tardiness penalty, which is referred to as α-Earliness-Tardiness. A proof is given that shows that even under a simple distance-dependent exponential radio path loss assumption, the problem is NP-complete. The remainder of the paper then focuses on timeslot-based scheduling. We formulate this problem as a Mixed-Integer Linear Program (MILP) that is shown to be solvable in polynomial time using a proposed minimum cost flow graph construction. Three energy-efficient online traffic scheduling algorithms are then introduced for common vehicular scenarios where vehicle position is strongly deterministic. The first, i.e., Greedy Minimum Cost Flow (GMCF), is motivated by our minimum cost flow graph formulation. The other two algorithms have reduced complexity compared with GMCF. The Nearest Fastest Set (NFS) scheduler uses vehicle location and velocity inputs to dynamically schedule communication activity. The Static Scheduler (SS) performs the same task using a simple position-based weighting function. Results from a variety of experiments show that the proposed scheduling algorithms perform well when compared with the energy lower bounds in vehicular situations where path loss has a dominant deterministic component so that energy costs can be estimated. Our results also show that near-optimal results are possible but come with increased computation times compared with our heuristic - lgorithms.
    IEEE Transactions on Vehicular Technology 03/2013; 62(3):1289-1302. DOI:10.1109/TVT.2012.2227071 · 1.98 Impact Factor
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    • "NCL i,t is set to 1 if Vehicle i would like to communicate to the AP at time t and is set to 0 otherwise. If Vehicle i has remaining communication requirements , Line [4], the algorithm selects a number of candidate communication locations where Vehicle i is closest to the AP, i.e., Lines [6] to [10]. In Line [6], the number of these candidate communication locations is limited by the minimum of size of the window, t ws , or remaining communication requirement, R i . "
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    ABSTRACT: Roadside infrastructure can be used provide a wide variety of commercial services in vehicular ad hoc networks. One particular challenge is that of providing roadside radio coverage in highway locations where wired electricity is not available. In this case, roadside access points (APs) powered by renewable energy such as solar power, is a viable alternative. The cost of provisioning this type of roadside infrastructure is dependent on the average power consumption of the AP, and can be reduced by energy efficient scheduling. In this paper, we consider the problem of satisfying vehicle communication requirements while minimizing the energy needed by the roadside access point. The problem is formulated as a Mixed Integer Linear Program (MILP) which provides an upper bound for the performance of any realizable scheduling algorithm. We then propose a Nearest Fastest Set (NFS) scheduler that uses vehicle location and velocity inputs to address the problem. Results from a variety of experiments show that the proposed scheduling algorithm performs well when compared to the performance bound.
    Proceedings of the Global Communications Conference, 2010. GLOBECOM 2010, 6-10 December 2010, Miami, Florida, USA; 01/2010
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