eCMT-SCTP: Improving Performance of Multipath SCTP with Erasure Coding Over Lossy Links

Performance of transport protocols on lossy links is a well-researched topic, however there are only a few proposals making use of the opportunities of erasure coding within the multipath transport protocol context. In this paper, we investigate performance improvements of multipath CMT-SCTP with the novel integration of the on-the-fly erasure code within congestion control and reliability mechanisms. Our contributions include: integration of transport protocol and erasure codes with regards to congestion control; proposal for a variable retransmission delay parameter (aRTX) adjustment; performance evaluation of CMT-SCTP with erasure coding with simulations. We have implemented the explicit congestion notification (ECN) and erasure coding schemes in NS-2, evaluated and demonstrated results of improvement both for application goodput and decline of spurious retransmission. Our results show that we can achieve from 10% to 80% improvements in goodput under lossy network conditions without a significant penalty and minimal overhead due to the encoding-decoding process

An optimized discrete wavelet transform compression technique for image transferring over wireless multimedia sensor network

Transferring images in a wireless multimedia sensor network (WMSN) knows a fast development in both research and fields of application. Nevertheless, this area of research faces many problems such as the low quality of the received images after their decompression, the limited number of reconstructed images at the base station, and the high-energy consumption used in the process of compression and decompression. In order to fix these problems, we proposed a compression method based on the classic discrete wavelet transform (DWT). Our method applies the wavelet compression technique multiple times on the same image. As a result, we found that the number of received images is higher than using the classic DWT. In addition, the quality of the received images is much higher compared to the standard DWT. Finally, the energy consumption is lower when we use our technique. Therefore, we can say that our proposed compression technique is more adapted to the WMSN environment

DONC: Delay-based Opportunistic Network Coding Protocol

International audienceGenerally, vehicular ad hoc networks (VANETs) carry information public in nature, which benefits most of the vehicular nodes involved. Therefore broadcasting data becomes an interesting option for disseminating data in VANETs. Broadcasting also offers advantages of flexibility and lack of a defined topology. However broadcasting in dense networks can cause collisions due to unnecessary packet retransmissions (broadcast storm problem). Delay-based vehicular broadcast mechanisms have been proven efficient in reducing redundant packet transmissions in dense networks. However, packet losses due to poor wireless medium quality and high mobility render delay-based mechanisms highly incapable of reducing number of packet retransmissions. In this paper, we present a Delay-based Opportunistic Network Coding protocol called 'DONC', which uses Network Coding opportunistically to improve dissemination of broadcast data in loss-prone VANETs and reduce packet retransmissions. We simulate DONC protocol in ns2 and compare it with a delay-based VANET broadcast mechanism. Results prove that DONC protocol outperforms other delay-based mechanisms, specially in the scenario of lossy VANETs

Network coding for wireless communication networks

This special issue includes a collection of 19 outstanding research papers which cover a diversity of topics on the application of network coding in wireless communication networks.published_or_final_versio

Energy Efficient and Reliable Wireless Sensor Networks - An Extension to IEEE 802.15.4e

Collecting sensor data in industrial environments from up to some tenth of battery powered sensor nodes with sampling rates up to 100Hz requires energy aware protocols, which avoid collisions and long listening phases. The IEEE 802.15.4 standard focuses on energy aware wireless sensor networks (WSNs) and the Task Group 4e has published an amendment to fulfill up to 100 sensor value transmissions per second per sensor node (Low Latency Deterministic Network (LLDN) mode) to satisfy demands of factory automation. To improve the reliability of the data collection in the star topology of the LLDN mode, we propose a relay strategy, which can be performed within the LLDN schedule. Furthermore we propose an extension of the star topology to collect data from two-hop sensor nodes. The proposed Retransmission Mode enables power savings in the sensor node of more than 33%, while reducing the packet loss by up to 50%. To reach this performance, an optimum spatial distribution is necessary, which is discussed in detail

Use of Clustering-based Routing Protocols in Low Power and Lossy Networks � A Survey

Internet of Things (IoT) is the one of the emerging field today, which consists of various resource-constrained devices that are limited in resources and work in the lossy wireless network. Therefore, IoT requires efficient routing protocol so that devices can communicate fast and power efficiently. Among different protocols available for wireless networks, Routing Protocol for Low Power and Lossy Networks (RPL) is a protocol specially standardized by IETF for efficient communication between IoT devices. Routing technique is one of the important factors of a routing protocol, which affects the performance of a protocol. In recent years, researchers contributed to improving RPL performance by providing various solutions and clustering is one of those ways to improve RPL performance by using Cluster- parent based Destination Oriented Directed Acyclic Graph (DODAG). In this paper, we discuss the various clustering-based routing protocols in a Low power and lossy networks (LLNs) and concludes that this survey might be helpful for future researchers

A Survey on Multimedia-Based Cross-Layer Optimization in Visual Sensor Networks

Visual sensor networks (VSNs) comprised of battery-operated electronic devices endowed with low-resolution cameras have expanded the applicability of a series of monitoring applications. Those types of sensors are interconnected by ad hoc error-prone wireless links, imposing stringent restrictions on available bandwidth, end-to-end delay and packet error rates. In such context, multimedia coding is required for data compression and error-resilience, also ensuring energy preservation over the path(s) toward the sink and improving the end-to-end perceptual quality of the received media. Cross-layer optimization may enhance the expected efficiency of VSNs applications, disrupting the conventional information flow of the protocol layers. When the inner characteristics of the multimedia coding techniques are exploited by cross-layer protocols and architectures, higher efficiency may be obtained in visual sensor networks. This paper surveys recent research on multimedia-based cross-layer optimization, presenting the proposed strategies and mechanisms for transmission rate adjustment, congestion control, multipath selection, energy preservation and error recovery. We note that many multimedia-based cross-layer optimization solutions have been proposed in recent years, each one bringing a wealth of contributions to visual sensor networks