scholarly journals MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Omar Elizarraras ◽  
Marco Panduro ◽  
Aldo L. Méndez ◽  
Alberto Reyna

The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput.

2013 ◽  
Vol 470 ◽  
pp. 611-616
Author(s):  
Xuan Jie Ning ◽  
Hai Zhao ◽  
Mao Fan Yang ◽  
Dan Wu

This paper is concerned with the capacity of ad hoc networks employing pure ALOHA medium access control (MAC) protocol under the effect of different transmission power levels and variable data rate control. The data rate of a certain link is related to the signal to interference plus noise ratio (SINR), and SINR is, in turn, related to the transmitted power and link distance. The increasing power conducts a high data rate, resulting in the high interference of networks. Consequently, the optimum power that yields maximum network throughput is a tradeoff between transmission rate and network interference. Mathematical model analysis for the ad hoc network capacity are presented in the paper. A revised expression to the approximate calculating of the capture probability in networks is proposed.


2010 ◽  
Vol 40-41 ◽  
pp. 462-468 ◽  
Author(s):  
Xiao Yun Chen ◽  
Sha Liu ◽  
Long Jie Li

The performance of backoff algorithm plays an important role in designing efficient Medium Access Protocols for Ad hoc networks. In this paper, we propose three backoff algorithms for Ad hoc networks. The first algorithm aims at higher fairness, and the second aims at stronger adaptivity. Then, we combine the first two algorithms to propose an optimized backoff algorithm. We use NS2 to simulate Ad hoc network environment to evaluate the performance of our improved backoff algorithms. The results show that our algorithms exhibit a significant improvement in throughput and fairness with the existing BEB and AASC algorithm.


2014 ◽  
Vol 644-650 ◽  
pp. 3103-3107
Author(s):  
Peng Wang ◽  
Hai Li ◽  
Ben Li Ye ◽  
Chen Chen ◽  
Yu Bao Wang

With the growing application diversification in Ad Hoc networks, it is particularly important to support prioritization of traffic and ensure that critical data can be delivered more reliably and faster in an emergency scene. We mainly study on the improvement of statistics based multi-priority medium access control (MAC) protocol, including the channel occupancy statistic and the backoff mechanism. We conduct comprehensive simulations based on the OPNET Modeler and account for the success rate results with theoretical analysis. The simulation results show that the proposed algorithm can simultaneously guarantee high success rate and low delay for high-priority packets.


Author(s):  
Abdullah Masrub

In contrast to infrastructure-based networks, in wireless ad hoc networks nodes can discover and communicate with each other directly without involving central access points. In this mode of multi-hop networks, all nodes have equal right to access the medium. Hence, the performance of wireless ad hoc networks is mostly limited by traffic congestion. To alleviate such a problem, Cognitive Radio (CR) technology can be used. In this chapter, a CR-based Medium Access Control (MAC) layer for wireless ad hoc networks is investigated. The authors focus on Cognitive MAC protocols for an unlicensed user, which can be enabled to access the large amount of unused spectrum allocated for a licensed user in an intelligent way without causing any harmful interference. They propose a cognitive MAC protocol based on the theory of the Partially Observed Markov Decision Process (POMDP), which sense the radio spectrum, detect the occupancy state of different primary channels, and then opportunistically communicate over unused channels. The objective is to benefit as much as possible from the available spectrum opportunities by making efficient decisions on which channels to access, which ensures maximization of the throughput of the secondary user.


Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2691 ◽  
Author(s):  
Yao Liu ◽  
Hongjing Zhou ◽  
Jiawei Huang

Cooperative communication is an effective method of improving the transmission performance for vehicular ad hoc networks. However, the rapid movement of vehicles leads to frequent changes in network topology and reduces the probability of successful data transmission on the medium access control (MAC) layer. In this paper, we propose an Optimal Cooperative Ad hoc MAC protocol (OCA-MAC) based on time division multiple access (TDMA). OCA-MAC utilizes multiple cooperative nodes to forward data, so as to improve the probability of successful data transmission. It chooses cooperative nodes according to direct successful transmission probability, communication range between potential helper node and destination node, and available time slot. Meanwhile, in order to avoid excessive transmission redundancy caused by multiple cooperative forwarding, the optimal number of cooperative forwarding nodes is obtained through analysis of a probabilistic model. Simulation results show that OCA-MAC improves the successful data transmission rate and reduces the number of transmission times and transmission delay compared to the multichannel TDMA MAC protocol (VeMAC) and the cooperative ad hoc MAC protocol (CAH-MAC).


2019 ◽  
Vol 8 (4) ◽  
pp. 10446-10452

In Cognitive Radio Ad Hoc Networks (CRAHNs), the Medium Access Control (MAC) protocol should handle the diverse Quality of Service (QoS) requirements of data packets of various classes generated by the nodes. The delay and reliability requirements of various applications should be considered while assigning the channels to the nodes. Hence in this paper, we propose to design a channel quality based MAC protocol for CRAHNs. In this technique, a channel with best Channel Quality Indicator (CQI) is chosen as the Common Control Channel (CCC). The CCC is assigned dynamically in each round. The channels with higher weights are assigned to higher priority traffic classes. Initially backup channels are assigned only to the nodes with higher priority real-time traffic. If a data channel is not available for any lower priority traffic, then the backup channels of higher priority traffic can be temporarily assigned to the lower priority traffic nodes. By simulation results, we show that the proposed technique reduces packet drop rate, error rate and increases packet delivery ratio and throughput.


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