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This paper proposes a MAC protocol for ad hoc networks using In-band Full-duplex (IBFD) wireless communications, which are named as AdHoc-FDMAC. To utilize IBFD communications in ad hoc networks, this protocol modifies a number of control frames in the IEEE 802.11 Distributed Coordination Function (DCF) MAC standard. Here, the detailed time sequences for all types of IBFD communications are shown for the data transmission and routing. In this paper, the probability and throughput equations for IBFD communications in different situations have been derived. The performance of the proposed AdHoc-FDMAC has been analysed in terms of probability, throughput, and routing time. The Maximum throughput of AdHoc-FDMAC has been found to be 48.34 Mbps, and it is compared with a recently published ad hoc MAC as well as with the conventional HD MAC. The AdHoc-FDMAC outperforms the recently published ad hoc MAC and conventional HD MAC by 16.80% and 66.50% throughput gain, respectively. AdHoc-FDMAC incorporates the existing Ad hoc On-demand Distance Vector (AODV) routing protocol, but this AODV routing is utilized here using IBFD communications. This paper also compares the routing time of the IBFD-based AODV with the conventional AODV. The result shows that the IBFD-based AODV requires 33.33% less routing time than that of the conventional AODV for 3-hop distance between the transmitter and receiver. This paper suggests that the AdHoc-FDMAC protocol provides much more throughput in ad hoc networks by utilizing IBFD communications. [ABSTRACT FROM AUTHOR]

In view of the security threats posed inside and outside the network due to the weaknesses of network protocols and systems, power line and wireless converged communications have security problems in communication connections that appear in environments where heterogeneous networks overlap. In order to cope with the problems of network delay and data transmission security in smart grid, this paper proposes an online monitoring security protection method based on edge nodes, which manages user trust under the premise of not leaking grid user data, and establishes a personalized machine learning model. This method not only guarantees users a secure communication experience, but also ensures users' real-time network connection and content acquisition, and can obtain a fast and personalized user experience. [ABSTRACT FROM AUTHOR]

Summary: Wireless sensor networks (WSN) have high value in the field of wireless communications. As the earliest WSN clustering protocol, Low Energy Adaptive Clustering Hierarchy (LEACH) can effectively reduce the energy consumption of data transmission in sensor networks. However, LEACH has some problems such as cluster head nodes are unevenly distributed. In this paper, a unified heuristic bat algorithm (UHBA) is proposed to optimize elections in cluster heads. This algorithm guarantees that the election of cluster heads can freely transform both global search and local search. Meanwhile, comparing with several other variants of the bat algorithm in CEC2013 test suite, it can be seen from results that UHBA has better performance. Moreover, the application of the algorithm on LEACH is better than other algorithms, which further proves that the algorithm has better results. [ABSTRACT FROM AUTHOR]

Networks consisting of wireless sensors are extensively used in many applications. Decentralized Erasure Codes (DEC) were introduced to store the sensed data in the wireless sensor network itself before transmitting the sensed data from wireless nodes to gateway or query nodes. Data at the failed nodes can be reconstructed by accessing other nodes in the network in DEC setup. In a traditional DEC setup, it is required to access k nodes out of n nodes to reconstruct the data at the failed node. Also, the reconstruction at failed node is subjected to intruder attacks raising security concerns. To reduce the number of nodes required to reconstruct the data at failed nodes and to ensure communication security, in this paper, decentralized erasure codes were constructed from optimal locally recoverable codes and Blom's key pre-distribution protocol, which exploits the generator matrix nature of constructed code, was implemented. From the simulations, we can infer that the proposed scheme performs better than other existing methods that use Reed–Solomon codes in terms of network load and error count per sent packet. Furthermore, it is shown that the proposed scheme ensures secure and efficient communication between nodes to overcome intruder interference. [ABSTRACT FROM AUTHOR]

Secure data communication is the need of hour today specifically when the wireless communication channel is insecure. We are proposing a protocol which can be customized in variety of situations. We want to use steganography as a complementary tool for cryptography. The protocol utilizes the nature of communication protocol and it is even useful for places where data hiding and cryptography is illegal or can't be performed because of various reasons. We are giving a name to these kinds of networks as disturbed networks. The proposed peer to peer protocol is very useful for insecure channels and disturbed networks and we provide complete analysis to validate its utility. The method is a convenient stop and wait protocol which provides unbeatable security and suitable for mobile phones as well. At the same time, for intruder's perspective, there is no encryption involved which is a very important aspect. [ABSTRACT FROM AUTHOR]

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Recent research in mobile ad-hoc networks (MANETs) mostly deals to minimize the broadcast expenses of route discovery by controlling the query-broadcast. In this regard, a variety of broadcast-repealing schemes have been proposed, and employed to improve effectiveness and efficiency in various aspects of route-discovery considering time and energy. These schemes mainly focus on reducing unnecessary propagation of route-query by repealing the query-broadcast. Time-to-live based broadcast is the most common controlled-flooding scheme widely used in routing protocols. Recently some other broadcast-repealing schemes are proposed which work based on chasing-policy. The critical and analytical assessment to evaluate these schemes such aspects is of great importance. In this paper, we investigate their query-diffusion process, and their merits and demerits. [ABSTRACT FROM AUTHOR]

An opportunistic network is a wireless ad hoc network that has frequently intermittent connectivity due to nodes’ mobility. These spare, unpredictable networks aim to solve the prolonged delay paths by a store-carry-forward scheme. It is difficult to determine the appropriate nodes to forward the messages since there are few opportunistic contacts. The nodes might decide based on the obtained data of the network as a guide to reach a destination. The aforementioned technique is not helpful in case the rate of change in the network topology is higher than the rate of data gathering due to usage restrictions and uncertain available information/knowledge of the future contacts. In this paper, to cope with the challenges imposed by the un-deterministic environment, a risk assessment strategy is considered to evaluate the short and long-term impact of each decision to find the optimal node/paths. This routing scheme can take advantage of the unanticipated connection to make the routing more flexible in short time and with less buffer usage. Our proposed risk assessment algorithms that are based on MALP are mixed with the knowledge about buffer management and network capacity. The prioritized messages to be disseminated as well as better decision to take a risk are the main contributions of this paper. Moreover, the self-adaptive threshold, distributed PID controller, is considered to tackle different threshold levels for each node individually. Numerical results prove that the proposed method drastically increases the delivery ratio and also minimizes the risk of exceeding resource consumption and packet loss. [ABSTRACT FROM AUTHOR]

A cooperative wireless-powered communication network protocol is proposed, in which user far away from a hybrid access point (H-AP) is capable of harvesting wireless powers by overhearing the uplink signals of users that are relatively nearer to the H-AP, in addition to downlink signal broadcast by the H-AP. In this setting, time allocations for the downlink transmission of the H-AP and the uplink transmission for the users are jointly optimized for two different purposes. First, the weighted sum-rate maximization problem is solved for a given total transmission time. Then, the total transmission time is minimized under a minimum rate constraint, and an efficient algorithm is also presented to solve the optimal solution by a line search strategy. Numerical results demonstrate that the proposed schemes significantly increase the far user's rate, which in turn improves user fairness and transmission delay. [ABSTRACT FROM PUBLISHER]

Fiber-Wireless (FiWi) networks typically combine an optical access network with a wireless access network so as to build on the respective strengths of the optical and wireless network technologies. Prior analytical throughput-delay studies of FiWi networks have typically considered heavy-loaded traffic models, i.e., constantly backlogged source nodes. In contrast, in this paper we present a more general comprehensive FiWi network throughput-delay analysis that encompasses Poisson (non-heavy) as well as heavy-loaded input traffic models. In addition, our analysis covers bandwidth assignments of wireless channels both at the hop distance level and at the node level, as well as a queuing model of dynamic bandwidth allocation in the optical access network. Our analysis provides insightful guidelines for setting the channel access probabilities for source traffic and relay traffic in FiWi networks. Our numerical evaluations demonstrate that prior studies which considered only heavy traffic loads gave misleading results for the delay performance of well-known access probability assignments. We correct and clarify these misleading results with our more general analysis for non-heavy traffic. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are mobile networks, which are automatically outspread on a geographically limited region, without requiring any preexisting infrastructure. Mostly, nodes are both self-governed and self-organized without requiring a central monitoring. Because of their distributed characteristic, MANETs are vulnerable to a particular routing misbehavior, called wormhole attack. In wormhole attack, one attacker node tunnels packet from its position to the other attacker nodes. Such wormhole attack results in a fake route with fewer hop count. If source node selects this fictitious route, attacker nodes have the options of delivering the packets or dropping them. For this reason, this paper proposes an improvement over AODV routing protocol to design a wormhole-immune routing protocol. The proposed protocol called defending against wormhole attack (DAWA) employs fuzzy logic system and artificial immune system to defend against wormhole attacks. DAWA is evaluated through extensive simulations in the NS-2 environment. The results show that DAWA outperforms other existing solutions in terms of false negative ratio, false positive ratio, detection ratio, packet delivery ratio, packets loss ratio and packets drop ratio. [ABSTRACT FROM AUTHOR]

Three factors have been often shown to significantly affect the reliability of real-time transmission in wireless local area networks-transmission rate, power, and packet size. We analyze these factors and determine the optimal combination of factors subject to time constraints that yields the most reliable transmission of real-time data. We propose a cross-layer framework to jointly design the routing and MAC protocol combined with our optimization approach. The approach under a non-real-time routing protocol that produces a path metric is compared with a real-time routing protocol. Additionally, the real-time routing protocol enhances a guaranteed rate with our approach. Our experiments reveal that real-time performance in terms of miss ratio and throughput is significantly increased in lossy link and heavy traffic environments. Miss ratio and average throughput are improved by up to 30% over a state-of-the art routing protocol and 35% over a MAC protocol, respectively. [ABSTRACT FROM AUTHOR]

This paper proposes to increase the efficiency energy of nodes which rapidly drops during the transmission of the LEACH (Low Energy Adaptive Clustering Hierarchy), using the method of the dual-hop layered in the sensor field. By introducing dual-hop method in the data transmission, the proposed single-hop method for short-range transmission and multi-hop transmission method between the cluster heads for remote transmission was introduce. By introducing a partial multi-hop method in the data transmission, a single-hop method for short range transmission method between the cluster heads for remote transmission was introduces. In the proposed DL-LEACH, the energy consumption of cluster head for remote transmission reduces and increases the energy efficiency of sensor node by reducing the transmission distance and simplifying the transmission routine for short-range transmission. As compared the general LEACH, it was adapted to a wider sensor field. [ABSTRACT FROM AUTHOR]

Abstract: Full duplex wireless communication is one of the enabling technologies of the fifth generation (5G) mobile telecommunication networks. It boosts up the bandwidth by enabling simultaneous data transmission and reception on a single channel. In this paper, we design a suitable medium access control (MAC) protocol for 5G networks to realize the benefit of full duplex communication. We also develop an analytical model to evaluate the performance of our proposed MAC protocol. [ABSTRACT FROM AUTHOR]

With the rapid increase of space applications, the amount of information to be transmitted between spacecrafts and ground stations increases exponentially and space–sky–ground Transport Control Protocol (TCP) network is highly demanded. However, the traditional TCP cannot be directly applied to space data communication. This article deeply studies the TCP/Network Coding (NC), which can effectively improve terrestrial wireless communication system throughput. Combined with characteristics of Space Communication Protocol Specification-Transport Protocol (SCPS-TP) and advantages of terrestrial TCP/NC, an improved protocol referred to as SCPS-TP/NC, is proposed for space data communication. This article provides detailed process of protocol design, mathematical modelling and throughput analysis of the proposed SCPS-TP/NC. Finally, we implement the SCPS-TP/NC protocol and evaluate its performance by Network Simulator (Version 2). Simulation results show that SCPS-TP/NC can effectively increase the end-to-end system throughput, reduce the packet loss rate, shorten the transmission delay and improve the Quality of Service (QoS) of space data communication to a certain degree. [ABSTRACT FROM AUTHOR]

Energy conserving MAC protocols performing adaptive duty-cycling mechanism have been widely studied to improve the energy efficiency in Wireless Sensor Networks (WSNs). In particular, several asynchronous low power listening (LPL) MAC protocols such as B-MAC, X-MAC and ContikiMAC transmit a long preamble or consecutive data packets for an efficient rendezvous between senders and receivers. However, the rendezvous results in the challenging problem of unnecessary channel utilization since the senders occupy a large portion of the medium. Furthermore, when a traffic generation time overlaps with other neighbouring nodes, they frequently encounter spatially-correlated contention incurring excessive channel contention. In this paper, we propose a novel traffic distribution scheme called an Energy Efficient Transmission Alignment (EETA), that shifts a traffic generation time of the application layer. By using a MAC layer feedback including contention information, the cross-layer framework determines whether the node delays its transmission or not. EETA is robust from the heavy contending environment due to its traffic distribution feature. We evaluate the performance of EETA through diverse experiments on the TelosB platform. The results show that EETA improves the overall energy efficiency by up to 35%, and reduces the latency by up to 48% compared to the existing scheme. [ABSTRACT FROM AUTHOR]

Transmission of system-critical control information plays a key role in efficient management of limited wireless network resources and successful reception of payload data information. This paper uses an orthogonal frequency division multiplexing (OFDM) architecture to investigate the detection performance of a time-domain approach used to detect deterministic control signalling information. It considers a type of control information chosen from a finite set of information, which is known at both transmitting and receiving wireless terminals. Unlike the maximum likelihood (ML) estimation method, which is often used, the time-domain detection technique requires no channel estimation and no pilots as it uses a form of time-domain correlation as the means of detection. Results show that when compared with the ML method, the time-domain approach improves detection performance even in the presence of synchronisation error caused by carrier frequency offset. [ABSTRACT FROM AUTHOR]

VANETs have emerged as an exciting research and application area. Increasingly vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened a myriad of possibilities for powerful and potential life-changing applications on safety, efficiency, comfort, public collaboration and participation, while they are on the road. Although, considered as a special case of a Mobile Ad Hoc Network, the high but constrained mobility of vehicles bring new challenges to data communication and application design in VANETs. This is due to their highly dynamic and intermittent connected topology and different application’s QoS requirements. In this work, we survey VANETs focusing on their communication and application challenges. In particular, we discuss the protocol stack of this type of network, and provide a qualitative comparison between most common protocols in the literature. We then present a detailed discussion of different categories of VANET applications. Finally, we discuss open research problems to encourage the design of new VANET solutions. [ABSTRACT FROM AUTHOR]

Buffer sizing is an important network configuration parameter that impacts the quality of service characteristics of data traffic. With falling memory costs and the fallacy that "more is better," network devices are being overprovisioned with large buffers. This may increase queueing delays experienced by a packet and subsequently impact stability of core protocols such as TCP. The problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environments such as time-varying channel capacity, variable packet inter-service time, and packet aggregation, among others. In this article we discuss these challenges, classify the current state-of-the-art solutions, discuss their limitations, and provide directions for future research in the area. [ABSTRACT FROM PUBLISHER]

Among synchronization protocols applied in wireless sensor network, reference broadcast synchronization (RBS) is one prominent protocol achieving very high accuracy of synchronization given that the broadcasting medium is available. However, that the protocol lacks packet loss tolerance brings about degraded performance in severe conditions of wireless channel. Also, the instantaneous synchronization used in this protocol results in time discontinuity, which might cause serious faults in the distributed system. In this study, we propose a packet loss tolerance and continuous synchronization mechanism for RBS. Then we verified the result through simulations. [ABSTRACT FROM AUTHOR]

Liu, Y.; Xu, Y.; Zhang, K., and Feng, Y., 2019. Hardware design of marine buoy data communication terminal based on the 1st generation Beidou navigation positioning system. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 639–645. Coconut Creek (Florida), ISSN 0749-0208. Aiming at the actual situation of marine buoy data monitoring and the problems of poor anti-interference performance, low fault tolerance coefficient and high energy consumption in current communication system, the hardware design of marine buoy data communication terminal based on the 1st generation Beidou navigation positioning system is proposed. Based on the marine buoy system, the overall structure of communication terminal is designed. The main components of the hardware are Beidou communication module and wireless network communication module, and the auxiliary parts are antenna and power supply module. The long-distance part uses the inherent data transmission mode of Beidou navigation system to communicate, while the short-range part uses the radio network communication protocol to complete the data transmission. There are two UART interfaces in the hardware, one is connected with the auxiliary cabin, which is responsible for receiving the related data of the auxiliary cabin, including azimuth, attitude and pressure sensing, and the other UART interface is connected with the Beidou communication module, which is responsible for receiving positioning and navigation data and transmitting remote data. The experimental results show that the design has high signal-to-noise ratio, strong fault-tolerant performance, high positioning accuracy and communication success rate, low energy consumption and perfect performance. [ABSTRACT FROM AUTHOR]

There is a significant interest in new wireless multiple access protocols that adaptively split a wide frequency channel into multiple sub-channels—perhaps of varying widths—and assign these sub-channels to competing transmissions. Existing protocols suffer from various limitations such as considerable protocol overhead, dependence on a centralized controller, and use of fixed-size channels. We introduce Ez-Channel, a novel MAC protocol that parsimoniously utilizes the OFDM sub-carriers to perform channelization and assignment of sub-channels to competing links. In addition to circumventing hidden and exposed terminal problems, Ez-Channel adapts channel assignments to the network topology. To eliminate the need for a centralized controller and to avoid an overwhelming amount of information exchange, the protocol uses a randomization technique enabling provably efficient localized decision making. Our extensive analytical and simulation studies show that Ez-Channel yields significant throughput improvements as compared to the state-of-the-art protocols. [ABSTRACT FROM AUTHOR]

Transmission Control Protocol (TCP) performs poorly over wireless networks. Some research indicates that the TCP congestion control mechanism may cause burstiness in the traffic flow. Numerous TCP segments are delivered simultaneously, while an acknowledgement of a retransmission is successfully received. Burstiness leads to a highly contentious network, which markedly increases the probability of packet loss on wireless networks. TCP pacing is a possible solutions for TCP burstiness on multi-hop networks. In this algorithm, TCP segment transmissions are distributed over the whole Round Trip Time. Most pacing protocols attempt to insert a delay interval into the TCP transmissions. However, there is a similar pacing algorithm in IEEE802.11, known as the contention window mechanism. In this paper, we first measure and analyze the way that the contention window size affects TCP throughput in different scenarios. We propose a cross-layer TCP pacing protocol by contention control in the MAC layer, called TCP Contention Control (TCP-CC). It adjusts the lower bound of the contention window in order to optimize the overall TCP throughput in both one-hop and multi-hop topology. Finally, comparative simulations are conducted in order to verify the improvements of our protocol on both TCP Reno and TCP Vegas. [ABSTRACT FROM AUTHOR]

IP-enabled sensors can be globally addressable by any Internet-connected entity, and therefore, their protection presents different challenges than that of traditional sensors, as they are subject to any potential attacker in the Internet. For this reason, specific security protocols must be developed to address the security requirements of IP-enabled sensors. An interesting approach to achieve this aim is the Ladon security protocol, which allows resource-deprived devices to efficiently implement end-to-end authentication, authorisation and key establishment mechanisms. However, in so limited environments such as sensor networks, not only efficient protocols must be defined, but they must also be optimally parameterised. This paper constitutes a step forward in this direction. First, a state transition model of the Ladon protocol is presented to analytically describe its behaviour. Then, this model is used to select the most effective parameterisation of the protocol in terms of message retransmissions and execution of cryptographic operations. The obtained results show that the selected parameterisation allows maximising the probability of a successful secure session establishment, while keeping the overhead introduced by the protocol low. Additionally, the performance comparison carried out shows that Ladon outperforms alternative approaches to achieve the same objective in terms of message transmission and reception operations. [ABSTRACT FROM AUTHOR]

It is widely known that Control Area Networks (CAN) are used in real-time, distributed and parallel processing which cover manufacture plants, humanoid robots, networking fields, etc., In applications where wireless conditions are encountered it is convenient to continue the exchange of CAN frames within the Wireless CAN (WCAN). The WCAN considered in this research is based on wireless token ring protocol (WTRP); a MAC protocol for wireless networks to reduce the number of retransmissions due to collision and the wired counterpart CAN attribute on message based communication. WCAN uses token frame method to provide channel access to the nodes in the system. This method allow all the nodes to share common broadcast channel by taken turns in transmitting upon receiving the token frame which is circulating within the network for specified amount of time. This method provides high throughput in bounded latency environment, consistent and predictable delays and good packet delivery ratio. The most important factor to consider when evaluating a control network is the end-to-end time delay between sensors, controllers, and actuators. The correct operation of a control system depends on the timeliness of the data coming over the network, and thus, a control network should be able to guarantee message delivery within a bounded transmission time. The proposed WCAN is modeled and simulated using QualNet, and its average end to end delay and packet delivery ratio (PDR) are calculated. The parameters boundaries of WCAN are evaluated to guarantee a maximum throughput and a minimum latency time, in the case of wireless communications, precisely WCAN. [ABSTRACT FROM AUTHOR]

Mobile ad-hoc network has limited battery power. Power consumption control is the main issue in mobile ad-hoc network. Node battery power is a precious resource that should be used in order to avoid the early termination of nodes. Energy management model and power consumption control flow chart is proposed to control power consumption by reducing data transmit time in mobile ad-hoc network. Simulation model has been used to analysis the energy consumption of a node. This has been achieved by estimating the time spent in transmission of data by node. The proposed model has been simulated using OMNET $$++$$ simulator. Simulation results show significant energy savings after applying the proposed model and flow chart. [ABSTRACT FROM AUTHOR]

Wireless sensor networks with mobile sinks, mWSNs, have attracted a lot of attention recently. This is because sink mobility can greatly alleviate the hotspot issue in WSNs and further prolong the network lifetime. However, sink mobility also causes unexpected changes in network topology and data routing paths, which can largely affect the routing performance in such networks. Design of efficient routing protocols for mWSNs has been a critical issue, and much work has been carried out in this aspect. In this article, we first classify existing protocols based on different design criteria and then present a survey of the state-of-the-art routing protocols in this area. We illustrate how each of the protocols works, and discuss their advantages and disadvantages. Finally, we point out some future directions for efficient routing in mWSNs. [ABSTRACT FROM AUTHOR]

Abstract: DCCP (Datagram Congestion Control Protocol) is a transport layer protocol that provides congestion control for unreliable data transmission. The congestion control mechanism embedded in DCCP adjusts the packet sending rate according to network condition. However, DCCP does not discriminate congestion losses and wireless link errors resulted from fading and thus it leads to unnecessary rate adjustment. In this paper, we proposed a mechanism to enhance bandwidth utilization of DCCP over wireless network. We employed a cross-layer loss discrimination scheme to distinguish congestion loss and fading loss. The cross-layer based mechanism detects frame loss in the data link layer in real-time to infer the actual fading loss rate. Thereafter, the fading loss can be excluded from the packet loss observed in the transport layer. Once the accurate congestion loss rate is calculated, the sender can make appropriate adjustment on the transmission rate that reflects the current congestion state along the transmitting path using the DCCP rate control procedure. Simulation results show that DCCP with our proposed CCID 3 rate control scheme can discriminate fading loss and achieve from 4.7% to 15.5% improvement on transmission throughput when the fading loss rate varies from 5% to 15% in wireless network. [Copyright &y& Elsevier]

Selection cooperation is an attractive cooperative strategy for wireless networks due to its simplicity and efficiency. In this paper, we consider a heterogeneous cooperative network consisting of different kinds of nodes with low-cost radios where the activities of one kind of nodes are triggered by the other kinds of nodes. This is a common scenario for many networks, such as wireless sensor networks. By exploiting the transmission relationship between heterogeneous nodes, we propose a selection cooperation protocol where inducing nodes can cooperate with the following nodes after their own transmissions for improving the communication reliability of the latter nodes. Through performance analysis, we show an interesting feature that the diversity-multiplexing tradeoff of the proposed protocol does not rely on the best relay selection method and the protocol always achieves the full diversity gain. We further develop an energy-efficient best relay selection method based on power control where the power consumption is minimized without decreasing the full diversity order. Simulation results demonstrate the good performance of the protocol and the remarkable energy reduction of the proposed best relay selection method. [ABSTRACT FROM AUTHOR]

The increased demand for wireless connectivity emphasizes the necessity of efficient wireless communication as resources such as the available spectrum and energy reserves become limiting factors for network proliferation. Recent advancements in software-defined radio enable high flexibility of the physical layer allowing fine grained transmission adjustments. Although communication efficiency can greatly benefit from physical layer flexibility, modern wireless protocols can neither handle these new opportunities nor allocate resources according to the overlying application needs. In this work we develop WhiteRate, a method for physical layer parameter adaptation that efficiently utilizes available energy and spectrum resources, while maintaining the desired quality of communication. Our solution adjusts the modulation and coding scheme, and channel width to achieve a communication profile that matches application requirements. We implement WhiteRate in GNUradio and evaluate it in both indoor and outdoor environments. We demonstrate improvements on two important fronts: spectrum utilization and energy efficiency. Moreover, we show that by using WhiteRate, both benefits can be achieved simultaneously. [ABSTRACT FROM AUTHOR]

Contemporary wireless multihop networks operate much below their capacity due to the poor coordination among transmitting nodes. In this paper, we present XPRESS, a cross-layer backpressure architecture designed to reach the capacity of wireless multihop networks. Instead of a collection of poorly coordinated wireless routers, XPRESS turns a mesh network into a wireless switch. Transmissions over the network are scheduled using a throughput-optimal backpressure algorithm. Realizing this theoretical concept entails several challenges, which we identify and address with a cross-layer design and implementation on top of our wireless hardware platform. In contrast to previous work, we implement and evaluate backpressure scheduling over a TDMA MAC protocol, as it was originally proposed in theory. Our experiments in an indoor testbed show that XPRESS can yield up to 128% throughput gains over 802.11. [ABSTRACT FROM AUTHOR]

Network mobility (NEMO) enables a group of nodes to connect to the back-end infrastructure during the movement. Because a vehicle must provide passengers good enough transmission quality, various access techniques, for example, 3 G/3.5 G, Wi-Fi or dedicated short range communication, can be simultaneously equipped to aggregate bandwidth and tolerate link failure. This paper extends the Session Initiation Protocol (SIP)-based NEMO framework to support multihoming. First, IEEE 802.21 Media Independent Handover (MIH) is integrated to manage multiple egress interfaces in an on-board unit (OBU). Second, a dynamic synchronization mechanism using the SIP SUBSCRIBE and NOTIFY methods is proposed to manage multiple OBUs in a vehicle. Furthermore, the framework is applied to public transportation systems, for example, bus, train, or mass rapid transit. Passengers may need to transit several times during their journeys. The transit behavior must induce a flood of signaling messages for location update. In this paper, the SIP REFER method is exploited to reduce signaling messages while a group of passengers have scheduled their transit in advance. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A wireless sensor network generally consists of huge range of inexpensive densely deployed detector nodes that have strictly forced sensing, computation, and communication capabilities. Due to resource restricted detector nodes, it is necessary to scale back the number of data transmission in order that average time period of detector and so the information measure consumption square measure improved. Knowledge aggregation is that the strategy of summarizing and mixing detector knowledge thus on minimizes the number of data transmission within the network. Wireless sensor networks square measure generally deployed in remote and hostile environments to transmit sensitive knowledge, detector nodes square measure in peril of node compromise attacks and security problems like knowledge confidentiality and integrity square measure very necessary. Therefore, wireless sensor network protocols, e.g., knowledge aggregation protocol, need to be designed with security. During this paper we have a tendency to investigate the link between security and knowledge aggregation methodology in wireless detector networks. [ABSTRACT FROM AUTHOR]

Medium access control overhead is the primary reason for low throughput in wireless networks. Performing blind contentions, contentions without any information of other contenders, and exchanging control message are time-consuming control operations. In this study, we propose a new MAC protocol called distributed sequential access MAC (DSA-MAC) which provides the transmission order without any explicit control operations. It may induce very light control overhead; therefore, compared to existing wireless MAC protocols, DSA-MAC can remarkably enhance network throughput. [ABSTRACT FROM AUTHOR]

In this paper, a proposed new wireless protocol so-called wireless controller area network is introduced. WCAN is an adaptation of its wired cousin, controller area network protocol. The proposed WCAN uses token frame scheme in providing channel access to nodes in the system. This token frame method follows the example used in wireless token ring protocol which is a wireless network protocol that reduces the number of retransmissions as a result of collisions. This scheme based on CAN protocol allows nodes to share a common broadcast channel by taking turns in transmitting upon receiving the token frame that circulates around the network for a specified amount of time. The token frame allows nodes to access the network one at a time, giving 'fair' chance to all nodes instead of competing against one another. This method provides high throughput in a bounded latency environment. The proposed WCAN protocol has been developed and simulated by means of QualNet simulator. The performances of this proposed protocol are evaluated from the perspective of throughput, end-to-end delay and packet delivery ratio, and are compared against the IEEE 802.11 protocol. Simulation results show that the proposed WCAN outperforms IEEE 802.11 based protocol by 62.5 % in terms of throughput with increasing network size. Also, it shows an improvement of 6 % compared to IEEE 802.11 standard at a higher data interval rate. [ABSTRACT FROM AUTHOR]

We consider an erasure multi-way relay channel (EMWRC) in which several users share their data through a relay over erasure links. Assuming no feedback channel between the users and the relay, we first identify the challenges for designing a data sharing scheme over an EMWRC. Then, to overcome these challenges, we propose practical low-latency and low-complexity data sharing schemes based on fountain coding. Later, we introduce the notion of end-to-end erasure rate (EEER) and analytically derive it for the proposed schemes. EEER is then used to calculate the achievable rate and transmission overhead of the proposed schemes. Using EEER and computer simulations, the achievable rates and transmission overhead of our proposed schemes are compared with the ones of one-way relaying. This comparison implies that when the number of users and the channel erasure rates are not large, our proposed schemes outperform one-way relaying. We also find an upper bound on the achievable rates of EMWRC and observe that depending on the number of users and channel erasure rates, our proposed solutions can perform very close to this bound. [ABSTRACT FROM AUTHOR]

Wireless sensor networks have found their way to countless applications in many different fields. Due to the restricted power availability these systems are faced with, custom wireless protocols have been designed. Many different protocols have already been conceived, yet each application will impose different requirements. In inertial motion tracking, sensor nodes are applied on the body allowing full body posture reconstruction. These nodes must not hinder or restrict the movements of the user in any way, meaning that a wireless approach is desirable. A suiting protocol that insures robust simultaneous functionality of at least 15 nodes at a rate of 100Hz is required. A TDMA based protocol with master/slave hierarchy is presented for the application at hand. Nodes dynamically decide on their role within the network at startup and reassess the network state regularly. Conflicting situations are handled whenever they arise and nodes react accordingly creating a fully plug-and-play system. Careful implementation of the protocol in embedded software allows data transmission of 19 nodes while each of them consumes an average current of only 3mA. [ABSTRACT FROM AUTHOR]