A secure medium access control protocol: Security versus performances

This paper discusses an application of a neural network in wireless sensor network security. It presents a multilayer perceptron (MLP) based media access control protocol (MAC) to secure a CSMA-based wireless sensor network against the denial-of-service attacks launched by adversaries. The MLP enhances the security of a WSN by constantly monitoring the parameters that exhibit unusual variations in case of an attack. The MLP shuts down the MAC layer and the physical layer of the sensor node when the suspicion factor, the output of the MLP, exceeds a preset threshold level. Backpropagation and particle swarm optimization algorithms are used for training the MLP. The MLP-guarded secure WSN is implemented using the Vanderbilt Prowler simulator. Simulation results show that the MLP helps in extending the lifetime of the WSN.

This paper studies the performance of the IEEE 802.11 standard MAC protocol for integrated H.263 video and data transmission in a single BSA (basic service area) of an infrastructure network. Data traffic is transmitted with the DCF (distributed coordination function), while video transmission is carried out with the PCF (point coordination function). By simulation, we evaluate the throughput and average MPDU (MAC protocol data unit) delay for various values of the CFP (contention free period) repetition interval and the CFP maximum duration. Numerical results show that if the CFP repetition interval is set too long, video-delay performance deteriorates drastically. We also study how channel transmission errors affect the performance of the protocol.

Abstract: Various medical applications consisting of heterogeneous requirements are supported by WBA networks. For reliable data transmission it is required to use an efficient medium access control protocol. Here, in this project, a dynamic Super frame structure-based MAC protocol is proposed by extending the standard principles from IEEE 802.15.6 which is a standard protocol, a mechanism for allocating dedicated slots with prioritization is used which is known to be Criteria Importance Through Inter-criteria Correlation, inorderto assign the allocation of slots for every sensor device. Values of sensor devices are calculated based on different sensors parameters by using CRITIC method. There by we compare our proposed work with the standard IEEE 802.15.6 MAC and other MAC protocols. By simulating it is shown that our proposed MAC protocol has performed better in Reliability, Throughput, Energy Efficiency and also Packet Delivery Delay. In the results it is shown that Reliability of data transmission has increased over more than 50% over the standard IEEE 802.15.6 MAC

Passive RFID systems typically utilize contention-based MAC protocols, such as the standard C1G2 protocol. While these protocols are easy to implement, they suffer from unfairness and low throughput. This paper proposes a token-based MAC protocol called Token-MAC for passive RFID systems. Token-MAC is designed to enable fair access to the medium for all tags without requiring a-priori knowledge of the tags or synchronization of the tags. We implement Token-MAC as well as a TDMA-based protocol and compare these approaches with the standard C1G2 protocol. Our experiments show that Token-MAC has a higher tag rate and better fairness than C1G2, and can achieve good performance over a longer range than the TDMA-based protocol. Token-MAC is therefore a viable solution for many passive RFID systems.

在分层移动节点的无线传感器网络中，网络的信息采集常常具有突发性和集中性。对低速无线个人区域网络IEEE802.15.4 MAC进行研究，针对采用直接数据传输的CSMA-CA机制在用户发送查询指令时，路由节点附近的传感器节点几乎同时进行数据采集和汇报，造成在传感器节点汇报数据时期出现大量的数据碰撞，导致传感器节点能量的大量损耗的问题，提出了一种基于IEEE802.15.4的能量高效的移动MAC协议。该协议采用带时隙的CSMA-CA机制，将超帧激活期划分成竞争期与非竞争期。竞争期内，传感器节点申请数据收发安排权，非竞争内进行无竞争的数据传输，减少了数据碰撞的概率，仿真实验表明基于IEEE802.15.4的能量高效的移动MAC协议具有能量高效性。 In hierarchical architecture for wireless sensor network with the mobile nodes, network information collected often has the sudden and concentration. IEEE802.15.4 MAC protocol is introduced In this paper .When the users send queries in their command, the sensor nodes near routing node almost simultaneously collect and report the sensing data, which will result in a large number of data crash and energy loss. To address this issue, we propose an energy-efficient mobile MAC protocol which is based on IEEE802.15.4. This protocol use CSMA-CA mechanism with the time slot to divide the super frame into the competition period and free period. In competition period, the sensor node arrangement to apply the right to send and receive data, while transmitting data using the form of competition-free in free period, which will reduce the probability of data collision. The simulation results show that our MAC protocol has a high per- formance.

With the onset of multimedia applications, Quality of Service (QoS) in 802.11-based wireless ad hoc networks has been an essential area to look into. Standard wireless protocols such as IEEE 802.11b and IEEE 802.11e have been deemed unsuitable for multimedia traffic transmission in an ad hoc (multihop) network environment due to the unique network characteristics. As an ad hoc network is infrastructureless and distributed in nature, it gives rise to several challenges in QoS provisioning. In this thesis, we focus on the research of three key areas on QoS in ad hoc networks namely, buffer management in the medium access control (MAC) layer, cross-layer design and flow admission control. Firstly, we study MAC layer buffer management in the IEEE 802.11e protocol. The IEEE 802.11e MAC protocol provides QoS for multimedia traffic by probabilistic priority queueing. Ad hoc networks tend to generate a large volume of network control packets for route maintenance and these control packets are typically queued in the highest priority queue. As a result, higher priority control traffic is always being served, consuming most of the bandwidth and results in poor network performance for data traffic. We examine this problem and propose a dynamic buffer management scheme to mitigate it. By setting different threshold levels in different priority queues, we allow lower priority data traffic to be served when the higher priority control traffic is deemed to be excessive. Simulation of our proposed scheme has shown that our approach yielded better network performance compared to the standard protocol in terms of packet delivery ratio and average delay. Secondly, we study the cross-layer interaction between the MAC and Network layers to identify its impact on QoS. We select the IEEE 802.11e MAC protocol and Ad-hoc On Demand Distance Vector (AODV) routing protocol in our study since they are standardized protocols for wireless networks. In IEEE 802.11e MAC protocol, lower priority traffic has a higher probability of being blocked. Hence, the MAC layer will inform the Network layer of a broken link through the link notification function. In this case, AODV will re-route the paths that traverse this link. As a result, higher priority traffic which shares the same link as the lower priority traffic will undergo the same re-routing procedures. We termed this phenomenon path correlation effect. Under high traffic load, the path correlation effect will be more intense and hence degrade the QoS of higher priority traffic. To break the path correlation effect, we propose a cross-layer design called the Bundled Virtual Circuit (BVC). Our proposed BVC scheme not only addresses the path correlation issues, but also provides priority treatment from the Network layer to the MAC layer. Through our simulations, our proposed cross-layer design approach is proven to provide better network performance than the 802.11e/AODV protocols in terms of packet delivery ratio and delay. Finally, we examine flow admission control at the routing layer in ad hoc networks. Standard routing protocols such as AODV performs routing on a shortest path basis. In the presence of multiple routes, hotspots are likely to form among the intermediate nodes and thus lead to network congestion. In addition, existing routes are not well-protected from the introduction of new routes. We propose a flow admission control algorithm to be used with AODV. Our algorithm allows routes to be created through available bandwidth and congestion estimation. During the route discovery phase, each node will be gauged on its estimated available bandwidth and its backlog of packets in the MAC buffer. If a node does not have sufficient bandwidth, or has too many backlogged packets compared to the requested flow rate, it will not participate in the route discovery process. From simulations, our new scheme is able to provide better network performance than the standard AODV protocol in terms of delay. Our work in this thesis focuses on QoS provisioning in ad hoc networks from the MAC and network layer perspectives. By studying the network characteristics and protocols’ behavior, we investigate the various problems of providing QoS in an ad hoc network environment and propose three different schemes to improve the QoS provisioning at the MAC and network layers. We believe that our work is able to provide some insights to the research area on QoS in ad hoc networks.

In a wireless body area network (WBAN), wireless biomedical sensors are placed around, on, or inside the human body. Given specific requirements, WBANs can significantly improve healthcare, diagnostic monitoring, and other medical services. However, the existing standards such as IEEE 802.11 and IEEE 802.15.4 have some limitations to meet all the requirements of WBANs. Many medium access control (MAC) protocols have been studied so far, most of which are derived from the IEEE 802.15.4 superframe structure with some improvements and adjustments. However, the MAC protocols do not provide the required quality of service (QoS) for various types of traffic in a WBAN. In this paper, a traffic-aware MAC (TA-MAC) protocol for WBANs is proposed, in which time slots are dynamically allocated on the basis of traffic priority, providing the required QoS. According to the performance evaluation results, the proposed TA-MAC is better than IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of transmission time, system throughput, energy efficiency, and collision ratio.

Several feedback-based mechanisms have been proposed to maximize the IEEE 802.11 MAC protocol efficiency by guaranteeing an optimal time-spreading of users' channel accesses. However, these solutions suffer from a significant unfairness problem in the presence of stations adopting the standard binary exponential backoff algorithm. Generally, a few legacy stations are sufficient to completely starve enhanced stations employing a modified 802.11 MAC protocol that adapts the backoff to the network contention level. In this paper we propose a credit-based scheme to enforce fairness in heterogeneous networks. Specifically, enhanced stations earn credits when releasing transmission opportunities granted by the standard protocol. The credits are a virtual currency spent by the enhanced stations to reclaim new transmission opportunities. In this paper, we apply our solution to the distributed mechanism for contention control named AOB L. Bononi et al. (2004). Simulation results show the effectiveness of the proposed mechanism in all the network scenarios considered.

The emergence of optical wireless networks (OWNs) is a potential solution to the quest for the increasing bandwidth demand. Existing bandwidth assignment strategies are not suitable for OWNs, considering factors such as differences between the physical properties of radio networks and OWNs. In order to eliminate collision, minimize delay and enhance system utilization and fairness, we propose the non-contention bandwidth assignment protocol called adaptive polling medium access control (APMAC) protocol for OWNs. The APMAC protocol involves association, data transmission and dissociation phases. Moreover, the APMAC protocol exploits features of the IEEE 802.15.7 visible light communication (VLC) standard. While assigning bandwidth to the visible light nodes (VLNs), the visible light access point (VLAP) establishes a polling table that contains the identity, buffer size and round-trip time of each VLN that issued bandwidth request. The contents of the polling table enable the computation of the maximum transmission unit and time-slot for each VLN that requests bandwidth assignment. In order to achieve convincing results, we simulate the protocol under varying network sizes ranging from 1 to 10 VLNs per access point, then we compare the results against the medium transparent medium access control (MT–MAC) protocol that is a non-contention MAC protocol. We demonstrate numerical results of our study considering average waiting time, packet collision, system utilization and fairness. Numerical results reveal that the APMAC protocol outperforms the MT–MAC protocol.

We propose a novel architecture, MAC protocol and admission control for high-capacity packet-switched ring networks. Nodes access the entire link capacity by transmitting and receiving packets in parallel on all available wavelengths. Packets are added to and dropped from the ring by 2/spl times/2 optical switches. The network control is simple since the load is balanced over the wavelengths at the physical layer. The proposed MAC protocol is based on credits. The admission control algorithm requires minimal processing complexity, and can follow fast traffic changes typical in data networks.

With the extensive application of wireless sensor networks, low energy consumption of nodes is the most important consideration.The medium access control MAC protocol is an important technology that structures first floor foundation network architecture. In this article by comparing the domestic and foreign research results, current several kinds of quite typical MAC protocol is analyzed according to the energy saved aspect. According to the special environment of coal mine, we got a MAC protocol which was suitable to mine.

Hierarchical cooperation (HC) has been proven in linear capacity scaling for ad hoc networks when density of nodes exists. This technology has recently been studied as a new generation network architecture (i.e., 5G). However, for cellular networks, there have been few studies on MAC protocols for HC in relation to signaling. In particular, energy consumption due to frequently changed clusters for maintaining consecutive ad hoc networks, and with respect to limited battery supply, is an important issue that should be addressed. In this paper, we propose an energy efficient HC based (EEHC-) TDMA MAC protocol aimed at alleviating energy depletion. Through a simulation, we analyze the EEHC-TDMA MAC protocol considering hierarchy, density, and distance. Finally, we show that an EEHC-TDMA MAC with hierarchy reduces energy consumption and also achieves maximum throughput close to the linear capacity scaling.

In recent years, spatio-temporal uncertainty has been a great challenge in the Media Access Control (MAC) protocol design for underwater acoustic networks (UANs). In this paper, a slotted based MAC protocol for UANs is proposed, called RV-SFAMA-MA, in order to solve the specific problems of UANs, such as long propagation, low channel utilization and luxurious underwater energy consumption. First, the sending time slot of the acknowledgment (ACK) control message is scheduled to avoid collision, and the appropriate ACK scheduling algorithm is selected by calculating the optimum capacity of UANs to solve the exposed terminal problem. Second, a multiple reception mechanism is introduced to improve the channel utilization, in which a novel RTS-VBF competition algorithm is proposed to determine the sending sequence of each node, so as to reduce the sum of network transmission delay and alleviate the funneling effect. The experiments show that compared with broadcast mac (BC-MAC) protocol and slotted floor acquisition multiple access (SFAMA) protocol, our RV-SFAMA-MA can achieve 25.44%-43.98% higher throughput and much lower energy consumption in a minitype UANs topology.

Ultrawide band (UWB) radio transmission scheme uses extremely low power and low duration pulses resulting in the use of extremely large transmission bandwidth. UWB has several advantages over conventional continuous wave radio communications like support for high data rates over short ranges, robustness to multipath interference and lack of significant fading. This technique based on impulse radio paradigm, offers great flexibility and enormous potential for future broadband wireless accessibility. In this work, an UWB based multiple access scheme is proposed. The potential of UWB is exploited within a distributed ad-hoc wireless system. A new medium access control protocol is designed for mobile computing applications taking into account, significant parameters needed for a reliable UWB communication. The model of ad-hoc system is simulated and the protocol implemented. The performance results derived from simulations are analyzed in terms of number of packets sent, number of packets received and efficiency. By implementing the proposed MAC protocol in a real ad-hoc network, the performance of the network can be improved significantly.

This era is witnessing a rising compulsion on the quality of healthcare. With the Wireless Body Area Networks, health monitoring has become more convenient and profitable since it consists of tiny wearable or implanted sensors deployed to monitor the health status of a person. Now, health can be continuously and effectively monitored where doctors can access the data and diagnose patients based on this data. Quality of service (Q.o.S) should be emphasized because data is of great significance. Considering this, many Q.o.S-aware Medium Access Control protocols or M.A.C protocols are developed concentrating on the different Q.o.S parameters like reliability, throughput, and delay. This paper provides a complete survey on the different Q.o.S-aware MAC protocols that exist for W.B.A.N’s.