A Backoff Algorithm for LOWPAN Based on the Dynamically Backoff Exponent

2015 ◽  
Vol 713-715 ◽  
pp. 1389-1393
Author(s):  
Ya Jun Zhang ◽  
Jin Liang Shi ◽  
Guo Rong Chen
Keyword(s):  
Ieee 802.15.4 ◽  
Mac Protocol ◽  
Markov Chain Model ◽  
Poor Performance ◽  
System Throughput ◽  
Chain Model ◽  
Backoff Algorithm ◽  
The Poor ◽  
Mathematical Derivation ◽  
Transmission Status

A mechanism that the backoff exponent changes dynamically was proposed aiming at the poor performance of backoff algorithm in IEEE 802.15.4 MAC protocol. The algorithm could adjust the initial backoff exponent according to the previous transmission status and the backoff exponent. A Markov chain model for the algorithm was established and the mathematical derivation for the model was carried out. The theoretical analysis and simulation results show that the model increases the channel access probability and system throughput. The optimized algorithm improves the performance of LOWPAN effectively.

scholarly journals Performance Analysis of WBAN MAC Protocol under Different Access Periods

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Pervez Khan ◽  
Niamat Ullah ◽  
Md. Nasre Alam ◽  
Kyung Sup Kwak
Keyword(s):  
Performance Metrics ◽  
Mac Protocol ◽  
Markov Chain Model ◽  
Wireless Body Area Network ◽  
Heterogeneous Traffic ◽  
System Throughput ◽  
Area Network ◽  
Chain Model ◽  
Access Methods ◽  
Qos Differentiation

The IEEE 802.15.6 is a new standard on wireless body area network (WBAN) for short-range, extremely low power wireless communication with high data rates in the vicinity of, or inside, a human body. The standard defines two contention-based channel access schemes: slotted ALOHA and carrier sense multiple access with collision avoidance (CSMA/CA) using an alternative binary exponential backoff procedure. The standard supports quality of service (QoS) differentiation through user priorities and access phases. In this study, we develop an analytical model for the estimation of performance metrics such as energy consumption, normalized throughput, and mean frame service time, employing a Markov chain model under nonsaturated heterogeneous traffic scenarios including different access phases specified in the standard for different user priorities and access methods. We conclude that the deployment of exclusive access phase (EAP) is not necessary in a typical WBAN using CSMA/CA because it degrades the overall system throughput, consumes more energy per packet, and results in higher delay for nonemergency nodes.

scholarly journals Modeling and Analysis of Additional Clear Channel Assessment to Improve Performance of IEEE 802.15.4-based MAC Protocol

2020 ◽  
Vol 3 ◽  
pp. 10-21
Author(s):  
Manjunath G. Asuti ◽  
Prabhugoud I. Basarkod
Keyword(s):  
Ieee 802.15.4 ◽  
Performance Metrics ◽  
Mac Protocol ◽  
Markov Chain Model ◽  
Wireless Channel ◽  
Chain Model ◽  
Clear Channel Assessment ◽  
Ieee 802.15.4 Standard ◽  
The Impact ◽  
Clear Channel

Design of the MAC protocol is crucial in all wireless sensor networks (WSNs) due to its influence on the performance of the transceiver, i.e. the most energy-consuming component of each sensor node. A mechanism known as “carrier sense multiple access with collision avoidance” (CSMA/CA) is used for accessing the wireless channel in the IEEE 802.15.4 standard-based MAC protocol in order to avoid collisions between the network’s communicating nodes. CSMA/CA relies on two clear channel assessments (CCA=2) for checking the status of the channel. In this paper, we develop an additional CCA algorithm for the two scenarios encountered in star topology-enabled WSNs. Next, we investigate the impact of an additional clear channel assessment (CCA=3) on performance in IEEE 802.15.4. We develop a Markov chain model for the proposed methodology, and validate it using Matlab. Simulation results show that there is a significant improvement of performance metrics in the IEEE 802.15.4 standard-based MAC protocol with an additional CCA

scholarly journals A Novel Cooperative ARQ Method for Wireless Sensor Networks

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Haiyong Wang ◽  
Geng Yang ◽  
Yiran Gu ◽  
Jian Xu ◽  
Zhixin Sun
Keyword(s):  
Energy Efficiency ◽  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Markov Chain Model ◽  
Relay Node ◽  
Wireless Sensor ◽  
System Throughput ◽  
Chain Model ◽  
Channel Fading ◽  
Relay Nodes

In wireless sensor networks, cooperative communication can combat the effects of channel fading by exploiting diversity gain achieved via cooperation communication among the relay nodes. A cooperative automatic retransmission request (ARQ) protocol based on two-relay node selection was proposed in this paper. A novel discrete time Markov chain model in order to analyze the throughput and energy efficiency was built, and system throughput and energy efficiency performance of proposed protocol and traditional ARQ protocol were studied based on such model. The numerical results reveal that the throughput and energy efficiency of the proposed protocol could perform better when compared with the traditional ARQ protocol.

scholarly journals Design and Modeling of Self-Adapting MAC (SaMAC) Protocol with Inconstant Contention Loss Probabilities

2018 ◽  
Vol 2018 ◽  
pp. 1-25
Author(s):  
Ante Kristić ◽  
Julije Ožegović ◽  
Ivan Kedžo
Keyword(s):  
Wireless Networks ◽  
Mac Protocol ◽  
Markov Chain Model ◽  
Loss Probability ◽  
Chain Model ◽  
Industrial Wireless Networks ◽  
802.11 Dcf ◽  
Loss Probabilities ◽  
Congested Networks ◽  
A Chain

Networks based on IEEE 802.11 standard are one of the main options for deployment in industrial environment. Degradation of throughput in congested networks and short-term unfairness are well-known drawbacks of 802.11 DCF and similar MAC protocols. Those shortcomings represent significant limitation in forecasted growth of wireless usage. This is especially important in industrial wireless networks (IWN) where the scalability of wireless MAC is one of the main requirements. In this paper, a novel self-adapting MAC protocol (SaMAC) is defined and mathematically modeled. SaMAC employs constrained countdown freezing enhanced with shifted window mechanism. As a result, the protocol outperforms 802.11 DCF standard as well as shifted contention window (SCW) and constrained countdown freezing (CPCF) protocols in achieved throughput, fairness, and jitter, while keeping simple implementation. Despite protocol’s simple design, it is shown that its mathematical model is extremely complex. For proposed protocol, the assumption of constant contention loss probability, which is normally used for modeling of MAC schemes, does not hold. In the presented multidimensional Markov chain model, a unique iterative method for determining contention loss probability is developed as well as a method for throughput calculation based on such a chain. Accuracy of the presented model is verified in several network scenarios. Considering the performance of the proposed protocol, authors believe that it could be of benefit to deploy it in heavily loaded wireless networks with timing constraints, such as IWNs.

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