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Long Lifetime Multipath Routing in Unreliable Wireless Multimedia Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor) ; Mehri, Bahman (Co-Advisor)
Abstract
Most of the current routing protocols in the WMSNs only consider the inter-path interference and not necessarily intra-path interference factor which is considered as one of the main causes of energy consumption in these networks. Among those protocols that consider this factor, none of them has ever come up with an algorithm capable of performing the routing without the need to use either the special hardware in the nodes (referred to as the GPS or directional antennas) or with the unrealistic assumption that the interference range is equal to the transmission range. The previously mentioned factors are critical in the sense that the former assumption results in more expensive sensor nodes...
Modem based on sphere packing techniques in high-dimensional Euclidian sub-space for efficient data over voice communication through mobile voice channels
, Article IET Communications ; Volume 9, Issue 4 , 2015 , Pages 508-516 ; 17518628 (ISSN) ; Boloursaz Mashhadi, M ; Heidari Khoozani, M ; Behnia, F ; Sharif University of Technology
Institution of Engineering and Technology
2015
Abstract
The increased penetration of cellular networks has made voice channels widely available ubiquitously. On the other hand, mobile voice channels possess properties that make them an ideal choice for high priority, low-rate real-time communications. Mobile voice channel with the mentioned properties, could be utilised in emergency applications in vehicular communications area such as the standardised emergency call system planned to be launched in 2015. This study aims to investigate the challenges of data transmission through these channels and proposes an efficient data transfer structure. To this end, a proper statistical model for the channel distortion is proposed and an optimum detector...
A Cross Layer Approach for Real-Time Communication in Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor) ; Khansari, Mohammad (Supervisor)
Abstract
Most of current the MAC protocols for Wireless Sensor Networks (WSNs) concern about energy efficiency rather than low latency. The main source of energy consumption in the MAC layer is idle listening, and most of these protocols use duty cycling for reducing energy consumption. But duty cycling method increases packet delivery latency. This problem is very critical in real time applications where packets should meet their deadline. There are some solutions for this problem. For example a node forwards data packets multi hop away instead of one hop in a single cycle. In this research, an efficient cross layer MAC protocol for real time applications is proposed. In this protocol multi hop...
Efficient codebook design for digital communication through compressed voice channels
, Article IET Communications ; Volume 10, Issue 18 , 2016 , Pages 2613-2620 ; 17518628 (ISSN) ; Behnia, F ; Sharif University of Technology
Institution of Engineering and Technology
2016
Abstract
The common voice channels existing in cellular communication networks provide reliable, ubiquitously available and top priority communication mediums. These properties make voice dedicated channels an ideal choice for high priority, real time communication. However, such channels include voice codecs that hamper the data flow by compressing the waveforms prior to transmission. This study designs codebooks of speech-like symbols for reliable data transfer through the voice channel of cellular networks. An efficient algorithm is proposed to select proper codebook symbols from a database of natural speech to optimise a desired objective. Two variants of this codebook optimisation algorithm are...
R2T-DSDN: reliable real-time distributed controller-based SDN
, Article Journal of Supercomputing ; Volume 77, Issue 11 , 2021 , Pages 12420-12457 ; 09208542 (ISSN) ; Jahangir, A. H ; Sharif University of Technology
Springer
2021
Abstract
Software-defined network (SDN) is an emerging network architecture in which the network control task is separated from packet forwarding. This architecture can be considered as a suitable infrastructure for fifth-generation mobile network (5G) and Internet of things due to its flexibility and dynamism. In real-time networks, time-sensitive packets that miss their deadlines are considered useless or less worthy. As with traditional networks, SDN is expected to support real-time communications and handle a variety of failures (including local controller, switch, and link failures) simultaneously. This study focuses on real-time communication of time-sensitive applications that operate on...
FRT-SDN: an effective firm real time routing for SDN by early removal of late packets
, Article Telecommunication Systems ; Volume 80, Issue 3 , 2022 , Pages 359-382 ; 10184864 (ISSN) ; Jahangir, A. H ; Sharif University of Technology
Springer
2022
Abstract
On-time delivery of network flows is crucial to ensure the quality of service of deadline-constrained applications. Today, real time applications have various uses in multimedia communications, the Internet of Things (IoT), and 5G (5th generation mobile network) technology. In Software Defined Network (SDN) architecture, the controller has a global view of the network. Hence, it is possible to enrich the features of the controller and/or forwarding devices to support real time communication. In this paper, we propose a firm real time software-defined approach (FRT-SDN) for real time communication and present a novel solution for the real time forwarding/routing of time-sensitive applications...