scholarly journals Dynamic Channel Assignment MAC Protocol for Cognitive Radio Ad Hoc Networks (CRAHNs)

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.

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.


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.


2014 ◽  
Vol 79 (3) ◽  
pp. 2383-2408 ◽  
Author(s):  
Ridi Hossain ◽  
Rashedul Hasan Rijul ◽  
Md. Abdur Razzaque ◽  
A. M. Jehad Sarkar

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.


IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 65781-65796 ◽  
Author(s):  
Chien-Min Wu ◽  
Meng-Sin Wu ◽  
You-Jie Yang ◽  
Cheng-Yue Sie

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