Analysis of IEEE 802.15.4 Beacon-Enabled MAC Protocol

This paper aims to develop several mathematical models to study medium access control (MAC) protocol in the IEEE 802.15.4 beacon-enabled mode with star topology. In particular, the MAC protocol which employs a slotted carrier-sense multiple access with collision avoidance (CSMA/CA) algorithm used in the contention access period (CAP) of a superframe is modelled. The analysis studies the effectiveness of the CSMA/CA algorithm and provides explicit mathematical expressions for power consumption, access delay, and data frame drop probability. The proposed models precisely follow CSMA/CA algorithm in MAC protocol of beacon-enabled mode and differ from those previously published in the literature as 1) they are derived based on data frame generation rate of end devices, 2) they provide a completed expression for frame access delay, and 3) lowpower states of end devices are considered for power efficiency evaluations. The paper shows how power consumption of end devices is improved on the balance with data frame delay. The validity of the proposed models is confirmed and complemented by extensive simulations

The impact of incapacitation of multiple critial sensor nodes on wireless sensor network lifetime

Kablosuz Algılayıcı Aglar (KAA) askeri güvenlik ve çevre gözetleme vb. kritik kontrol etme uygulamalarında sıkça kullanılmaktadır. Bu tip kritik uygulamarda algılayıcı dügümler ? düsman saldırıları için potansiyel birer hedeftir. KAA'ların en önemli performans ölçütlerinden birisi ag yasam süresi oldugu için çe¸sitli saldırılarla algılayıcı dügümlerden en kritik olanlarının ele geçirilmesi ve i¸slevsiz hale getirilmesi ag yasam süresini ciddi miktarda etkilemektedir. Bu çalı¸smada Dogrusal Programlama (DP) tabanlı iki tane özgün algoritma geli¸stirilmis olup kritik dügümlerin ele geçirilmesinin KAA ya¸sam süresine olan etkileri sistematik biçimde ele alınmı¸stır. Bu çalısma sonucunda kritik dügümlerin ele geçirilmesinin ag yasam süresini ciddi ölçüde düsürdügü sonuçlarına varılmıstır.Wireless Sensor Networks (WSNs) are envisioned to be utilized in many application areas such as critical infrastructure monitoring, therefore, WSN nodes are potential targets for adversaries. Network lifetime is one of the most important performance indicators in WSNs. Possibility of reducing the network lifetime significantly by eliminating a certain subset of nodes through various attacks will create the opportunity for the adversaries to hamper the performance of WSNs with a low risk of detection. However, the extent of reduction in network lifetime due to elimination of a group of critical sensor nodes has never been investigated in the literature. Therefore, in this study , we created a novel Linear Programming (LP) framework to model the impact of critical node elimination attacks on WSNs and explored the parameter space through numerical evaluations of the LP model. Our results show that critical node elimination attacks can shorten the network lifetime significantly

Scenario Based Study of On-demand reactive routing protocol for IEEE-802.11 and 802.15.4 standards

Routing data from source to destination is hard in Mobile Ad-Hoc Networks (MANET) due to the mobility of the network elements and lack of central administration. The main method for evaluating the performance of MANETs is simulation. In this paper performance of Ad-hoc On-demand Distance Vector (AODV) reactive routing protocol is studied by considering IEEE 802.11 and IEEE 802.15.4 standards. Metrics like average end-to-end delay, packet delivery ratio, total bytes received and throughput are considered for investigating simulation scenario by varying network size with 10 mps node mobility. Also simulation has been carried out by varying mobility for scenario with 50 nodes

An efficient MAC protocol based on hybrid superframe for Wireless Sensor Networks

The usage of wireless channels is based on Media Access Control (MAC) protocols, which allocate wireless resources and control the way that sensors access a shared radio channel to communicate with their neighbors. Designing low energy consumption, high efficiency MAC protocols is one of the most important directions in Wireless Sensor Networks (WSN). So far, MAC protocols in WSN are usually divided into two categories: contention-based MAC protocols and schedule-based MAC protocols. However, both protocols have their own advantages and disadvantages that sometimes it is hard to decide which one is better than the other one. A hybrid protocol is concerned a lot now in WSN, which is IEEE 802.15.4. It integrates the advantages of both contention-based and schedule-based mechanisms. However, this protocol has some improving spaces as well, which motivated us to further study it and proposed a new contention reserve MAC protocol, named CRMAC, under the inspiration of IEEE 802.15.4's superframe structure. Through a series of theoretical and simulation analysis, we show that CRMAC performs better in energy consumption, system delay and network throughput than IEEE 802.15.4 and LEACH (Low Energy Adaptive Clustering Hierarchy). CRMAC is especially suitable for short packet transmission under logy traffic networks, which is the main situation in WSN, so this protocol is practical in WSN

Data Aggregation and Cross-layer Design in WSNs

Over the past few years, advances in electrical engineering have allowed electronic devices to shrink in both size and cost. It has become possible to incorporate environmental sensors into a single device with a microprocessor and memory to interpret the data and wireless transceivers to communicate the data. These sensor nodes have become small and cheap enough that they can be distributed in very large numbers into the area to be monitored and can be considered disposable. Once deployed, these sensor nodes should be able to self-organize themselves into a usable network. These wireless sensor networks, or WSNs, differ from other ad hoc networks mainly in the way that they are used. For example, in ad hoc networks of personal computers, messages are addressed from one PC to another. If a message cannot be routed, the network has failed. In WSNs, data about the environment is requested by the data sink. If any or multiple sensor nodes can return an informative response to this request, the network has succeeded. A network that is viewed in terms of the data it can deliver as opposed to the individual devices that make it up has been termed a data-centric network [26]. The individual sensor nodes may fail to respond to a query, or even die, as long as the final result is valid. The network is only considered useless when no usable data can be delivered. In this thesis, we focus on two aspects. The first is data aggregation with accurate timing control. In order to maintain a certain degree of service quality and a reasonable system lifetime, energy needs to be optimized at every stage of system operation. Because wireless communication consumes a major amount of the limited battery power for these sensor nodes, we propose to limit the amount of data transmitted by combining redundant and complimentary data as much as possible in order to transmit smaller and fewer messages. By using mathematical models and computer simulations, we will show that our aggregation-focused protocol does, indeed, extend system lifetime. Our secondary focus is a study of cross-layer design. We argue that the extremely specialized use of WSNs should convince us not to adhere to the traditional OSI networking model. Through our experiments, we will show that significant energy savings are possible when a custom cross-layer communication model is used