An Improved Multi-Hop-Enabled Energy Efficient MAC Protocol for Underwater Acoustic Sensor Networks

Packet collisions occurred by hidden and local nodes in multi-hop enabled underwater acoustic sensor networks (UWASNs) have effect on throughput, energy efficiency and end-to-end delay. Existing Multi-HopEnabled Energy Efficient MAC Protocol for Underwater Acoustic Sensor Networks (MHEE MAC) utilized a double-phase contention resolution mechanism, which causes visit multiple time slot and energy overhead. In this paper, we propose a MAC protocol that use contention resolution mechanism with unique priority to provide energy efficiency. First, local nodes are eliminated comparing their priority and later, hidden nodes are mitigated. A simulation of proposed protocol is also developed to analyze the performance. Results obtained through simulation show that the proposed protocol achieves significantly lower energy consumption, reserve more energy and more stable throughput compared to MHEE-MAC, T-Lohi and slotted floor acquisition multiple access (S-FAMA)

A Framework for Analysis of Connectivity and Performance Bounds in Ad Hoc Networks and Its Application to a Slotted-ALOHA Scenario

In this paper, a framework is proposed to analyse the problems of connectivity and performance in ad-hoc networks through an analytical approach. To this aim, available results regarding the application of percolation theory to the study of connectivity in ad-hoc networks are exploited jointly with communication theory models in order to derive the configuration of network parameters that ensures long range connectivity among nodes and the corresponding available capacity on the wireless medium. The framework is then applied to a slotted ALOHA ad-hoc network. Theoretical and numerical results validate the approach and allow the derivation of interesting design principles for ad-hoc networks that consider the impact of physical and MAC-level parameters on network connectivity and end-to-end performance

A MAC protocol for underwater sensors networks

“The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-26401-1_37."Underwater sensor networks are becoming an important field of research, because of its everyday increasing application scope. Examples of their application areas are environmental and pollution monitoring (mainly oil spills), oceanographic data collection, support for submarine geo-localization, ocean sampling and early tsunamis alert. It is well-known the challenge that represents to perform underwater communications provided that radio signals are useless in this medium and a wired solution is too expensive. Therefore, the sensors in these network transmit their information using acoustic signals that propagate well under water. This data transmission type bring an opportunity, but also several challenges to the implementation of these networks, e.g., in terms of energy consumption, data transmission and signal interference. Few proposals are available to deal with the problem in this particular application scenario, and these proposals does not address properly the transmission of underwater acoustic signals. In order to help advance the knowledge in the design and implementation of these networks, this paper proposes a MAC protocol for acoustic communications between the nodes based on a self-organized time division multiple access mechanism. The proposal is still preliminary and it has only been evaluated in the laboratory; however, it represents a highly promising behavior that make us expect interesting results in real-world scenarios.Peer ReviewedPostprint (author's final draft

A SURVEY OF CONTENTION BASED MEDIUM ACCESS CONTROL (MAC) PROTOCOLS IN WIRELESS LAN

In wireless network, all radio nodes are tuned to the same frequency to interconnect and establish communication between each other. All nodes in the network broadcasts their packets over a common medium and in such scenario collisions are considered as instinctive attribute. Therefore, a proper method/regulation known as Medium Access Control (MAC) protocol is required to regulate and manage an efficient access to the common channel. The protocol is designed to allow radio nodes in wireless network to broadcast their packets in an orderly and efficient manner to eliminate the collision among them. It also provides a fair bandwidth sharing to all contending nodes in the network. To date, various MAC protocols was developed to regulate the communication access among all radio nodes in wireless network. This article presents an exhaustive survey of existing contention based MAC protocols, their operations, advantages and disadvantages. Other than that, a typical MAC protocol used in IEEE 802.11 wireless networks standard, such as Carrier Sense Multiple Access (CSMA) and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) also explained and presented in this article

Sualtı Akustik Algılayıcı Ağlarda Onay Paketi (ACK) Sayısının Ağ Başarımına Etkileri

Bu çalışmada sualtı akustik algılayıcı ağlar (SAAA’lar) için geliştirilen S-FAMA protokolü ile onun etkinliğini arttırmak için önerilen yaklaşımlardan olan Çoklu-ACK’daki onay (ACK) paket sayısının ağ başarımı üzerindeki etkileri ele alınmaktadır. Sualtı akustik algılayıcı ağlarda yüksek yayılım gecikmesi yüzünden bir onay (ACK) paketinin kaybının maliyeti yüksektir. Veri iletimi sırasında bir onay (ACK) paketi kaybolduğunda iletim sürecinin tekrarlanması enerji israfına neden olmaktadır. Bunu önlemek için önerilen yaklaşımlardan biri olan Çoklu-ACK sayesinde tek bir ACK yerine ACK dizisi kullanılarak bir onay paketinin başarıyla alınma olasılığı arttırılmaktadır. Bu çalışmada ACK dizisinde yer alan paket sayısının iş çıkarma oranı iyileştirmesi ve enerji verimliliği bakımından ağ başarımına etkileri matematiksel olarak analiz edilmektedir

Improving Channel Throughput of WLANs and Ad Hoc Networks Using Explicit Denial of Requests

A new Multiple Access Control scheme for wireless ad hoc networks and WLANs is proposed. This scheme uses explicit denial of channel requests and a busy tone to improve channel throughput. Performance analysis shows significant improvement when the network is under heavy traffic load

A Collision Avoidance Based Energy Efficient Medium Access Control Protocol for Clustered Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) are typically deployed in energy constrained environments where recharging energy sources and replacing batteries are not viable. This makes energy efficiency in UWSNs a crucial directive to be followed during Medium Access Control (MAC) design. Multiplexing and scheduling based protocols are not ideal for UWSNs because of their strict synchronization requirements, longer latencies and constrained bandwidth.This paper presents the development and simulation analysis of a novel cross-layer communication based MAC protocol called Energy Efficient Collision Avoidance (EECA) MAC protocol. EECA-MAC protocol works on the principle of adaptive power control, controlling the transmission power based on the signal strength at the receiver. EECA-MAC enhances the conventional 4-way handshake to reduce carrier sensing by implementing an enhanced Request to Send (RTS) and Clear to Send (CTS) handshake and an improved back-off algorithm.Simulation analysis shows that the measures taken to achieve energy efficiency have a direct effect on the number of packet retransmissions. Compared to the Medium Access with Collision Avoidance (MACA) protocol, EECA-MAC shows a 40% reduction in the number of packets that are delivered after retransmissions. This reduction, coupled with the reduced signal interference, results in a 16% drop in the energy utilized by the nodes for data transmission