Efficient Multihop Research Articles

Gateway Based Stable Election Multi Hop Routing Protocol for Wireless Sensor Networks

A gateway based energy efficient multi hop routing protocol for wireless sensor networks (WSNs) is introduced. The main aim of our paper is to design a protocol which minimizes energy consumption. Gateway nodes are deployed in sensing field. These gateway also reduce distance for reliable transmission of data. based protocol is better in terms of network lifetime protocol like SEP which is single hop

Energy Efficient Multi-Hop Wireless Sensor Networks with CMIMO-SM Scheme

Energy efficiency is one of the important hot issues in wireless sensor networks. In this paper, a multi-hop scheme based on a cooperative multi-input multi-outputspatial modulation technique is proposed in order to improve energy efficiency in WSN. In this scheme, the sensor nodes are grouped into clusters in order to achieve a multi-input multi-output system; and a simple forwarding transmission scenario is considered so that the intermediate clusters only forward packets originated from the source cluster down to the sink cluster. In order to verify the performance of the proposed system, the bit energy consumption formula is derived and the optimal number of hopsis determined. By qualitative experiments, the obtained results show that the proposed scheme can deliver the data over multiple hops consuming optimal energy consumption per bit.

A Burst Effort Broadcasting Approach of MPEG-4 Video Transmission for Intervehicle Communication

Efficient and real-time video broadcasting helps to improve driving safety and to make traveling fun for drivers. However, it is hard to structure vehicles into permanent network topologies and schedules to broadcast video streaming real-time in intervehicle communication (IVC) in a high-mobility vehicular environment. In order to achieve this, we have designed a burst effort broadcasting (BEB) approach for IVC, which considers the challenges of high mobility and multihop broadcast, as well as the features of MPEG-4 video streams to adapt to highway scenarios. The BEB approach is distributed in real time without protocol overhead and comprises a queuing procedure and a scheduling scheme. The queuing procedure consists of the preprocess of video transmission, including the video shaping of groups of pictures and sequential reordering video frames. Based on the queuing procedure, a mobility-adaptive scheduler is applied to handle the broadcast and rebroadcast of the video stream. The concept of macroscopic broadcast is utilized to increase the broadcast performance and the video perceived quality of service (PQoS), and to reduce the number of unnecessary redundant broadcasts. As an evaluation, the real MPEG-4 video was conducted in simulation and the broadcast performance was compared with another protocol by the metrics of peak-signal-to-noise ratio (PSNR) and loss of video frames in different broadcasting scenarios. Then, the results were analyzed. The simulation proved that this approach is an efficient multihop broadcast solution that does indeed provide a realistic solution to promote a higher degree of video PQoS on highways.

Efficient multihop transmission scheme for error-free relay forwarding in cooperative networks

Multihop cooperative communication is emerging as a key concept to extend the coverage area of the network and potentially increase the capacity. The spectral efficiency of such networks can be improved by adapting the transmission to time-varying channel conditions, referred to as incremental relaying. Although such incremental relaying concepts are progressively being studied, many challenges, such as erroneous transmissions by intermediate nodes and end-to-end delay of the network, limit its practical use due to lack of an efficient implementation. This paper proposes an efficient multihop incremental relaying technique. In this method, erroneous relay forwarding is mitigated, and the overhead for coordination among nodes is reduced by exploiting the implicit feedback channel available due to the broadcast nature of wireless transmissions. The proposed scheme fully leverages the benefit of overhearing and eliminates the additional feedback slots required for validation. Further, it ensures reliable forwarding of information, which optimizes the throughput of multihop networks. Thorough analysis of the proposed scheme is performed under different deployment environments, and the theoretical analyses presented in this paper are supported with results from extensive simulation studies. Copyright © 2013 John Wiley & Sons, Ltd.

EMBA: An Efficient Multihop Broadcast Protocol for Asynchronous Duty-Cycled Wireless Sensor Networks

In this paper, we propose an efficient multihop broadcast protocol for asynchronous duty-cycled wireless sensor networks (EMBA) where each node independently wakes up according to its own schedule. EMBA adopts two techniques of the forwarder's guidance and the overhearing of broadcast messages and ACKs. A node transmits broadcast messages with guidance to neighbor nodes. The guidance presents how the node forwards the broadcast message to neighbor nodes by using unicast transmissions. This technique significantly reduces redundant transmissions and collisions. The overhearing of broadcast messages and ACKs helps to reduce the number of transmissions, thus it minimizes the active time of nodes. We implement EMBA and conventional protocols of ADB and RI-MAC broadcast in ns-2 simulator to compare their performance. The simulation results show that EMBA outperforms ADB and RI-MAC broadcast in both sparse and dense networks. EMBA achieves lower message cost than the conventional protocols and significantly improves the energy efficiency in terms of both duty cycle and energy consumption.

Energy Efficient Multi-Hop Wireless Sensor Networks with Cooperative MIMO Scheme

For wireless sensor networks, energy efficiency is one of the most important subjects in recent research. In this paper, an energy-efficient multi-hop scheme based on cooperative MIMO (multiple-input multiple-output) technique is proposed for wireless sensor networks. Different from other papers, we consider a single cluster transmission scenario in which energy consumption is optimized by selecting the hop length and modulation constellation size. The optimal energy consumption formula is derived and proved mathematically. In addition, the minimum energy consumption per bit is calculated numerically.

Wireless Sensor Network Using Six Sigma Multi Hop Routing

The most significant problem in the design of wireless sensor networks is to coordinate the sensors with dynamism into a wireless communication network and route sensed data to the base station. The energy efficiency is the most important key point of the network routing designing. This paper presents the efficient multi hop routing algorithm to extend the lifetime of sensor networks and focuses by employing six sigma principles to obtain the Quality of Service. To attain QoS support, we have to find either a route to assure the application requirements or offering network response to the application when the requirements cannot be met.

An Efficient Traffic Information Forwarding Solution for Vehicle Safety Communications on Highways

Efficiently propagating adequate and effective traffic information to drivers helps increase driving safety and reduces traffic jams on highways. To achieve this, we designed an overlay solution that considers the challenges of propagating multisource information caused by vehicle mobility and multihop forwarding. The overlay solution is composed of a mobility-adaptive information reduction scheme (IR scheme) and a vehicle-adaptive cluster-to-cluster multihop forwarding method (VAC method). The IR scheme creates a mobility-adaptive cluster to represent local traffic information. The purpose of the scheme is to simplify individual high-speed movements and reduce large amounts of information broadcasts. Based on the results of the IR scheme, the VAC method selects the optimal relay node of the intercluster forwarding pair to increase the efficiency of multihop propagation. In the simulation, we compared network performance with two other protocols by defining three objective metrics of driving-perceived quality under different traffic scenarios and analyzed the results. Furthermore, we explored protocol overhead, broadcasting reduction ratio, and technological deviations to verify the advantages and efficiencies of our solution. The simulation proves that our solution is an efficient multisource and multihop forwarding framework that allows well-connected vehicular networks to disseminate a higher degree of correct traffic information, particularly for highway safety-related information.

Energy-Efficient Space-Time Coded Cooperation in Outage-Restricted Multihop Wireless Networks

Due to the limited energy supplies of nodes in many applications such as wireless sensor networks, energy efficiency is crucial for extending the lifetime of these networks. This paper addresses the cooperative transmission for outage-restricted multihop wireless ad hoc networks. The source node wants to transmit messages to a single destination. Other nodes in the network may operate as relay nodes. In this paper, new multihop cooperative protocol is proposed using the space-time codes for the purpose of energy savings, subject to a required outage probability at the destination. We restrict the cooperation to nodes along a chosen route. Two efficient power allocation schemes are derived, which depend only on the statistics of the channels. Furthermore, three efficient cooperative multihop transmissions are proposed when arbitrary distributed space-time codes are used. The proposed cooperative protocols offer different degrees of energy efficiency, spectral efficiency, complexity, and signalling overhead. Compared to non-cooperative multihop routing, an energy saving of up to 72% is achievable in line networks with 3 relays and an outage probability constraint of 10-3 at the destination.

Spectral Efficient Multihop Relaying Based on Alternate Transmission

A spectral efficient multihop relaying scheme is proposed based on scheduling the source transmission in alternate time slots. Each relay processes its received signal and forwards it in the subsequent time slot. An interference cancellation mechanism is developed to eliminate the interference term at each relay caused by the source alternate-based transmission. The frame error probability and the achievable rate of the proposed scheme are evaluated. It is shown that the individual bit-by-bit detection at the destination performs almost as well as the optimal joint detection, and achieves a data rate that approaches the Shannon channel capacity limit. In addition, the proposed scheme significantly outperforms the conventional orthogonal multihop transmission in terms of the achievable data rate, especially for larger numbers of hops, with slightly inferior frame error rate performance.

An Efficient Data Dissemination Scheme for Warning Messages in Vehicular Ad Hoc Networks

Vehicular ad hoc networks (VANETs) are expected to be used for the dissemination of emergency warning messages on the roads. The emergency warning messages such as post crash warning notification would require an efficient multi hop broadcast scheme to notify all the vehicles within a particular area about the emergency. Such emergency warning applications have low delay and transmission overhead requirements to effectively transmit the emergency notification. In this paper, an adaptive distance based backoff scheme is presented for efficient dissemination of warning messages on the road. The proposed scheme adaptively selects the furthest vehicle as the next forwarder of the emergency message based on channel conditions. The detailed performance figures of the protocol are presented in the paper using simulations in the OPNET network simulator. The proposed protocol introduces lower packet delay and broadcast overhead as compared to standard packet broadcasting protocols for vehicular networks.

Intelligent rate control for supporting real-time traffic in WLAN mesh networks

To provide high quality of service (QoS) for delay sensitive real-time traffic in wireless local area network-based (WLAN) mesh networks is a challenging task. In particular for real-time flows subject to multiple hops, mobility and time-varying channel, the performance of real-time flows will be degraded greatly. Efficient allocation and management of resources, such as transmission rate and throughput, is a crucial element and an attractive and efficient way for interconnecting access points (APs) to form an efficient multihop WLAN mesh network supporting QoS. Considering that IEEE 802.11 WLAN physical layers (PHYs) provide multiple transmission rates by employing different modulations and channel coding schemes, it is an important issue how to select the transmission rate so that the performance is improved, since each link generally has different characteristics with other links. In order to support real-time traffic, an efficient intelligent rate control algorithm is proposed in this paper, which aims to improve the system performance by adaptively adjusting the transmission rate to the current channel status. Based on the learning the local information of each node, the proposed algorithm can achieve accurate channel estimation without any extra implementation effort and modifications to the current 802.11 standard. And each node is able to select the optimized transmission rate, so that the system performance can be improved obviously. The proposed scheme also offers an appealing combination of the allocation of transmission rate and the current link condition. Based on the basic relationship between them, the intelligent rate control algorithm maximizes the throughput with periodic learning of channel variation and system status. Theoretical analysis proves that the proposed algorithm is quickly convergent. Detailed simulation and numerical results show the proposed rate control algorithm closely approximates the ideal case with the perfect knowledge about the channel. Compared with the existed schemes, the proposed algorithm can also significantly improve the system performance in terms of packet loss rate, end-to-end delay and throughput.

MobileMAN: integration and experimentation of legacy mobile multihop ad hoc networks

Although research on mobile ad hoc networks has been ongoing for some time, there are relatively few experiences with real ad hoc networks in laboratory testbeds, and users never use multihop ad hoc networks. This seems due to a gap between what end users might find useful, and what research is currently addressing. Indeed, a large portion of research activities concentrate on the development of novel solutions to optimize lower-layer protocols in often unrealistic settings, while little attention is devoted to the quality of service (QoS) these networks may provide to end users in realistic applicative scenarios. The MobileMAN project tried to contribute to reduce this gap by promoting a research plan aimed at combining theoretical research with the integration of developed solutions in prototypes to be used for validating them in realistic small- and medium-scale scenarios (few hops and 10‐20 nodes). The aim is to design and integrate a full protocol stack and experimentally quantify the QoS the system is able to provide to the users. This research approach points out that, also in this limited setting, several problems still exist to construct efficient multihop ad hoc networks. In the next article [1] we discuss how cross layering can be exploited to fix some performance problems identified in our analyses.

Design and performance of an enhanced IEEE 802.11 MAC protocol for multihop coverage extension

Ad hoc communication is gaining popularity, not only for pure ad hoc communication networks but also as a viable solution for coverage extension in wireless networks. Especially for upcoming WLAN hotspots, this is an interesting option to decrease installation costs. In this article we introduce a new MAC protocol that needs only marginal changes to the standard and enables efficient multihop networking. We advocate the use of multiple IEEE 802.11 channels, where one channel is reserved as a common signalling channel for the task of assigning the others (data channels) among wireless terminals. The proposed MAC protocols are based on a four-way handshake over the common signalling channel, while data transmission occurs on a dedicated channel. We propose a further optimization applying multiple wireless network interface cards. This improvement in performance comes at the price of a slightly more complex hardware. Two different simulation models are implemented to investigate our approach. The first model investigates the MAC protocol and its improvements, while the second model analyzes the multihop performance in terms of delivery ratio and transmission delay. BY means of numerous simulations we present the performance of our MAC approach in comparison with two standard approaches in terms of bandwidth, packet delivery, and transmission delay. For our performance evaluation we apply the IEEE 802.11a technology, but we note that our approach can also be used for IEEE 802.11b.