02248nas a2200169 4500008003900000245006400039210006200103250000800165260007700173300001400250490000600264520162100270100002201891700002101913700002001934856012401954 2015 d00aMobile Ad hoc networks (MANETs) for multimedia transmission0 aMobile Ad hoc networks MANETs for multimedia transmission a3rd bEncyclopedia of Information Science and Technology (3rd Ed.), IGI Global a6239-62480 v93 a

Mobile Ad hoc Networks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. A node in MANETs could act as a router while having also the possibility of being the sender or receiver of information. MANETs offer the freedom to use mobile devices and move independently of the location of base stations (and outside their coverage) with the help of other network devices. The ability of MANETs to be self-configured and form a mobile mesh network, by using wireless links, make them very suitable for a number of cases that other type of networks cannot operate. In addition, MANETs do not require vast technological investments. An ideal application area for the utilization of MANET technology is for instance any disaster scenario in which the fixed infrastructure is incapacitated or non-existent. In this case it is important to ensure that a suitable communication solution is established within the very first critical hours of an incident, considering national or cross-border emergency incidents. What is missing, however, from this type of networks is the so called a “killer application” that could boost its utilizations in the real world. Real time multimedia applications have the potential to turn MANETs into a very attractive solution in wireless networks taking into account its unique characteristics. Our motivation for this article is to present the shortcomings and the current state of the art in MANETs in regards to the transmission of multimedia data, which is a promising application area.

1 aGkamas, Apostolos1 aBouras, Christos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/mobile-ad-hoc-networks-manets-multimedia-transmission?language=el01507nas a2200169 4500008004100000245005300041210005300094300001200147490001300159520095000172100001701122700002101139700002201160700002301182700002001205856011201225 2014 eng d00aCross Layer Design for Video Streaming in MANETs0 aCross Layer Design for Video Streaming in MANETs a328-3380 v9, No. 23 a

Mobile Ad hoc NETworks (MANETs) are becoming more essential to wireless communications due to
growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications
and especially video transmission. In this work, we propose a cross-layer design that aims to improve the performance of video transmission using TCP Friendly Rate Control (TFRC). Our design provides priority to video packets and exploits information from the MAC layer in order to improve TFRC?s performance. The proposed cross-layer design utilizes SNR measurements along the routing path, in order to make the route reconstruction procedure more efficient. Simulation results show that both the use of traffic classification and the SNR utilization lead to important improvements in terms of end-to-end Quality of Service (QoS).

1 aAdam, George1 aBouras, Christos1 aGkamas, Apostolos1 aKapoulas, Vaggelis1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/cross-layer-design-video-streaming-manets?language=el01399nas a2200169 4500008004100000245004900041210004900090260001400139300001200153520084200165100002101007700002601028700002601054700002001080700001901100856011001119 2014 eng d00aEnhancing simulation environment with TRAFIL0 aEnhancing simulation environment with TRAFIL bCRC Press a391-4153 a

This chapter presents TRAFIL, a comprehensive tool for enhancing execution of simulations. It provides an overview of the tool, its architecture and its functionalities. It explains how TRAFIL en-hances the entire simulation procedure including graphical setup of simulation scenarios, automated execution of simulations, flexible handling and storage of simulation trace files and presentation of plots based on processing of simulation results. It presents the concept of metafiles that provides TRAFIL with the flexibility to handle heterogeneous simulation environments. The chapter also compares TRAFIL performance with other similar tools and finds that it offers significantly im-proved performance. It therefore concludes that TRAFIL offers both a rich set of simulation en-hancement functionalities and top performance.

1 aBouras, Christos1 aCharalambides, Savvas1 aDrakoulelis, Michalis1 aKioumourtzis, G1 aStamos, Kostas uhttps://telematics.upatras.gr/telematics/publications/enhancing-simulation-environment-trafil?language=el01947nas a2200181 4500008004100000245007700041210006900118260001700187300001000204520129100214100002101505700002001526700002201546700002301568700002201591700001701613856013501630 2013 eng d00aEvaluation of video transmission in emergency response ad - hoc networks0 aEvaluation of video transmission in emergency response ad hoc ne cJuly 29 - 31 a27-353 a

Mobile Ad hoc NETworks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. MANETs are also essential in Emergency Response situation where network information flow between deployed units is vital. In such cases voice and video transmission is essential to form a global view of the situation and decide on action. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. In this work we evaluate the use of multiple interfaces and multiple channels for Video Transmission in Emergency Response Ad hoc Networks. We also evaluate the video transmission with rate adaptation. Aim of this paper is to tune multiinterfaces and multi-channels video transmission mechanisms in order to support better emerging situations and offer a solution to have acceptable transmission of the necessary video streams so that the control can get a complete overall picture of the situation and decide on the action to be taken. The simulation evaluation performed shows that multi-interfaces and multi-channels video transmission offers many advantages in Video Transmission in Emergency Response Ad hoc Networks.

1 aBouras, Christos1 aKioumourtzis, G1 aGkamas, Apostolos1 aKapoulas, Vaggelis1 aPolitaki, Dimitra1 aTsanai, Enea uhttps://telematics.upatras.gr/telematics/publications/evaluation-video-transmission-emergency-response-ad-hoc-networks?language=el02076nas a2200181 4500008004100000245006100041210006000102260001800162300001600180520144600196100002101642700002301663700001901686700002001705700002201725700002401747856012301771 2013 eng d00aFeedback-based Adaptation for Improved Power Consumption0 aFeedbackbased Adaptation for Improved Power Consumption cMarch 25 - 28 a 562 - 568 3 aIn this paper we present a feedback-based adaptation mechanism that adjusts the transmission power of a wireless card on commodity PCs depending on the quality of the connection. Our purpose is to manage the available power in order to achieve lower power consumption without negatively affecting the user?s perception of connection quality. We based our implementation on an existing theoretical model and focused on resolving problems and removing assumptions which made it inefficient in real life implementation. The initial model manages to minimize the power consumption in networks with exactly two nodes. In this paper, we extend the model to consider the possibility of the existence of a base station, where any number of nodes can be connected. Our objectives for the base station are to minimize the power consumption and guarantee continuous connectivity for all mobile nodes. We implement the adaptation mechanism for a specific adapter with open sources drivers thus allowing necessary modifications. We conduct a number of real world experiments. The results indicate that power consumption can be significantly reduced for nodes that are either almost stationary or slowly moving (e.g. at walking speed), without any significant increase in packet loss. The results are quite important as nowadays mobile devices with limited battery life time use tethering to become base stations for other devices like in ad-hoc networks.1 aBouras, Christos1 aKapoulas, Vaggelis1 aStamos, Kostas1 aKioumourtzis, G1 aTavoularis, Nikos1 aStathopoulos, Nikos uhttps://telematics.upatras.gr/telematics/publications/feedback-based-adaptation-improved-power-consumption?language=el01718nas a2200169 4500008004100000245005600041210005500097260001600152300001000168520114400178100002101322700001901343700002001362700002601382700002601408856011401434 2013 eng d00aSimulation design and execution: The case of TRAFIL0 aSimulation design and execution The case of TRAFIL c29-31 July  a27-343 a

This paper presents the enhancements that we have done on the TRAFIL (TRAce FILe) framework, which significantly extend its capabilities in the areas of simulation design and execution. In particular, TRAFIL now offers the possibility to design, create, execute and review NS-2 simulation scenarios, on top of its ex-isting post-simulation trace analysis functionalities. The enhancements make TRAFIL a complete wrapper around the NS-2 simulator, allowing the user to perform all steps from pre-simulation design to actual simu-lation execution in an automated way and fast and convenient post-simulation analysis of potentially large amount of data. The paper describes the new TRAFIL architecture and how these enhancements were im-plemented with the goal of relieving NS-2 users from the often cumbersome tasks of script writing and vali-dating, while also enabling them at to go behind the TRAFIL environment and into the simulator internals at any time. The paper presents the new GUI functionalities developed for that purpose, the approach that we took for their design and how these fit in the overall TRAFIL architecture.

1 aBouras, Christos1 aStamos, Kostas1 aKioumourtzis, G1 aCharalambides, Savvas1 aDrakoulelis, Michalis uhttps://telematics.upatras.gr/telematics/publications/simulation-design-and-execution-case-trafil?language=el02675nas a2200157 4500008004100000245007800041210006900119300001400188520206500202100002102267700001902288700002002307700002602327700002602353856013802379 2013 eng d00aA tool for automatic network simulation and processing tracing data files0 atool for automatic network simulation and processing tracing dat a 90 - 1103 a

One of the most highly regarded discrete event simulators used for network simulation is NS-2 (Network Simulator). NS-2 executes simulation scenarios producing various data of which trace files are considered the most beneficial for evaluating a simulation. In this paper we present the design considerations and implementation of a new tool that can be used both in TRAce FILe analysis and execution of simulations using NS-2. Although TRAFIL is primarily based on NS-2 trace files it can be extended to support a number of different other simulation trace file formats. It aims to make the execution of a great number of network simulations quicker, and the extraction of results from a large amount of data more flexible and productive. In order to accomplish the above tasks TRAFIL presents a novel way of interpreting, parsing, reading and eventually using NS-2 trace files. It introduces the notion of ??metafiles?? and ??sub metafiles?? throughout the procedures of trace file recognition and parsing, making the overall analysis operation substantially efficient and faster than alternative approaches. Metafiles and sub metafiles are used to encode NS-2 trace file structures enabling a more abstract approach to the trace file processing operation. Furthermore, TRAFIL facilitates the overall trace file analysis task by offering the opportunity to store each trace file as well as every Quality of Service (QoS) measurement produced for each trace file. Following the trace file recognition and processing operations, the information contained in a trace file is presented through a Graphical User Interface (GUI) offered by TRAFIL along with a variety of data, metrics and statistics related to simulation results. Finally, the tool offers the opportunity to execute custom Structured Query Language (SQL) queries to the local database and to completely automate the simulation procedure by enabling the user to execute NS-2 scripts as well as perform a simulation of a video transmission using the Evalvid-RA framework.

1 aBouras, Christos1 aStamos, Kostas1 aKioumourtzis, G1 aCharalambides, Savvas1 aDrakoulelis, Michalis uhttps://telematics.upatras.gr/telematics/publications/tool-automatic-network-simulation-and-processing-tracing-data-files?language=el01688nas a2200169 4500008004100000245007000041210006600111260001500177300000900192520109400201100002101295700002301316700002201339700002001361700001701381856012001398 2012 eng d00aA cross - layer design for video transmission with TFRC in MANETS0 across layer design for video transmission with TFRC in MANETS c24-27 July a5-123 a

Mobile Ad hoc NETworks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. In this work, we propose a cross-layer design that aims to improve the performance of video transmission using TCP Friendly Rate Control (TFRC). Our design provides priority to video packets and exploits information from the MAC layer in order to improve TFRC?s performance. The proposed cross-layer mechanism utilizes Signal to Noise Ratio (SNR) measurements along the routing path, in order to make the route reconstruction procedure more efficient. Simulation results show that both the use of traffic categorization and the SNR utilization lead to important improvements of video transmission over the mobile Ad hoc network. More specifically, simulations indicate increased average Peak Signal to Noise Ratio (PSNR) for the received video, increased throughput and packet delivery ration, as well as reduced average end-to-end delay.

1 aBouras, Christos1 aKapoulas, Vaggelis1 aGkamas, Apostolos1 aKioumourtzis, G1 aAdam, George uhttps://telematics.upatras.gr/telematics/publications/cross-layer-design-video-transmission-tfrc-manets?language=el02233nas a2200133 4500008004100000245008300041210006900124300001400193520168700207100002101894700002201915700002001937856014201957 2012 eng d00aPerformance Evaluation of Ad Hoc Routing Protocols for Military Communications0 aPerformance Evaluation of Ad Hoc Routing Protocols for Military  a216 - 2343 aMobile Ad hoc networks (MANETs) are of much interest to both the research community and the military because of the potential to establish a communication network in any situation that involves emergencies. Examples are search-and-rescue operations, military deployment in hostile environment, and several types of police operations. One critical open issue is how to route messages considering the characteristics of these networks. The nodes act as routers in an environment without a fixed infrastructure, the nodes are mobile, the wireless medium has its own limitations compared to wired networks, and existing routing protocols cannot be employed at least without modifications. Over the last few years, a number of routing protocols have been proposed and enhanced to address the issue of routing in MANETs. It is not clear how those different protocols perform under different environments. One protocol may be the best in one network configuration but the worst in another. This article provides an analysis and performance evaluation of those protocols that may be suitable for military communications. The evaluation is conducted in two phases. In the first phase, we compare the protocols based on qualitative metrics to locate those that may be fit our evaluation criteria. In the second phase, we evaluate the selected protocols from the first phase based on quantitative metrics in a mobility scenario that reflects tactical military movements. The results disclose that there is no routing protocol in the current stage without modifications that can provide efficient routing to any size of network, regardless the number of nodes and the network load and mobility.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/performance-evaluation-ad-hoc-routing-protocols-military-communications?language=el01582nas a2200145 4500008004100000245006300041210006200104300001400166490000700180520106300187100002101250700002201271700002001293856012301313 2012 eng d00aTFMCC vs ASMP: Lessons learned from performance evaluation0 aTFMCC vs ASMP Lessons learned from performance evaluation a349 - 3720 v223 a

In this article we present a simulation-based comparison of one of the best-known multicast congestion control schemes—TCP-friendly Multicast Congestion Control (TFMCC)—against our proposed Adaptive Smooth Multicast Protocol (ASMP). ASMP consists of a single-rate multicast congestion control mechanism which takes advantage of the RTCP Sender (SR) and Receiver Reports (RR) in order to adjust the sender?s transmission rate in respect of the network conditions. The innovation in ASMP lays in the ?smooth? transmission rate, which is TCP-friendly and prevents oscillations. We use an integrated simulation environment named Multi- Evalvid-RA for the evaluation of the two congestion control schemes. Multi-Evalvid-RA provides all the necessary tools to perform simulation studies and assess video quality by using both network-centric metrics along with video quality measurements. Performance evaluation results show that ASMP is a very efficient solution for rate-adaptive multimedia applications and a serious competitor to well-known TFMCC.

1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/tfmcc-vs-asmp-lessons-learned-performance-evaluation?language=el01870nas a2200157 4500008004100000245006700041210006600108260001600174300001000190520130000200100002101500700001901521700002001540700002601560856012601586 2012 eng d00aTRAFIL: A tool for enhancing simulation TRAce FILes processing0 aTRAFIL A tool for enhancing simulation TRAce FILes processing c24 -27 July a61-643 aNS-2 (Network Simulator) is one of the most popular discrete event simulators used for network simulation. Trace files produced by NS-2 provide very useful information for post simulation analysis. This paper presents the architecture and development considerations for a TRAce FILe analysis tool, which intends to simplify the management of trace files generated during network simulations. The tool is focused on NS-2 trace files, but can be extended to handle a variety of simulation trace files formats. Its purpose is to make the execution of a large number of network simulations faster, and the extraction of results from a large amount of data more flexible and productive. TRAFIL introduces a novel way of interpreting, parsing, reading and eventually utilizing NS-2 trace files by using "metafiles" and "sub-metafiles" during the trace file recognition and process procedures, making the overall operations more abstract, substantially efficient and faster than alternative approaches. Furthermore, TRAFIL facilitates the whole trace file analysis task, offering the opportunity to store each trace file as well as every measurement produced for each trace file. The tool aims to aid the analysis of simulation results offering features that other tools in this area have been missing.1 aBouras, Christos1 aStamos, Kostas1 aKioumourtzis, G1 aCharalambides, Savvas uhttps://telematics.upatras.gr/telematics/publications/trafil-tool-enhancing-simulation-trace-files-processing?language=el01587nas a2200133 4500008004100000245010900041210006900150300001500219520099900234100002101233700002201254700002001276856015701296 2011 eng d00aAdaptive Smooth Simulcast Protocol (ASSP) for Video Applications: Description and Performance Evaluation0 aAdaptive Smooth Simulcast Protocol ASSP for Video Applications D a 143 - 1773 aIn this paper, we present Adaptive Smooth Simulcast Protocol (ASSP) for simulcast transmission of multimedia data over best-effort networks. ASSP is a new multiple-rate protocol that implements a single rate TCP-friendly protocol as the underlying congestion control mechanism for each simulcast stream. The key attributes of ASSP are: (a) TCP-friendly behavior, (b) adaptive per-stream trans- mission rates, (c) adaptive scalability to large sets of receivers and (d) smooth transmission rates that are suitable for multimedia applications. We evaluate the performance of ASSP under an integrated simulation environment which combines the measurements of both network and video performance metrics. We also com- pare ASSP against other proposed solutions and the results demonstrate that the performance of ASSP is significantly better than the tested solutions. Finally, ASSP is a practical solution with very low implementation complexity for video trans- mission over best-effort networks. 1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/adaptive-smooth-simulcast-protocol-assp-video-applications-description-and-performance?language=el01740nas a2200169 4500008004100000245008700041210006900128260003400197520106500231100002101296700002301317700002201340700002001362700001701382700002201399856014901421 2011 eng d00aCross-Layer Mechanism for Efficient Video Transmission over Mobile Ad Hoc Networks0 aCrossLayer Mechanism for Efficient Video Transmission over Mobil cNovember 30 – December 3 aAbstract- Mobile ad hoc networks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. This paper presents a cross-layer mechanism for efficient video transmission over this type of networks. The proposed mechanism consists of a priority-scheduling algorithm, at the network layer, and the use of the IEEE 802.11e standard at the MAC layer. The priority-scheduling algorithm takes into account the frame type of the MPEG-4 video file in order to provide different priorities to the most important video packets. At the MAC layer, the IEEE 802.11e protocol assigns the highest priority to video applications to reduce delay and packets losses due to other competing traffic. This design is easily implemented in any ad hoc wireless network as an extension on the AODV MANET routing protocol. Simulation results conducted with the network simulator ns-2 show the advantages of the proposed design.1 aBouras, Christos1 aKapoulas, Vaggelis1 aGkamas, Apostolos1 aKioumourtzis, G1 aAdam, George1 aTavoularis, Nikos uhttps://telematics.upatras.gr/telematics/publications/cross-layer-mechanism-efficient-video-transmission-over-mobile-ad-hoc-networks?language=el01878nas a2200169 4500008004100000245010300041210006900144260002600213520119000239100002101429700002301450700002201473700002001495700001701515700002201532856015401554 2011 eng d00aPerformance Evaluation of Routing Protocols for multimedia transmission over Mobile Ad hoc Network0 aPerformance Evaluation of Routing Protocols for multimedia trans cOctober 26 – 283 aAbstract— Mobile ad hoc networks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. The integration of mobile ad hoc devices inside vehicles has led to another type of networks, called Vehicular Ad hoc Networks (VANETs) which are also becoming important. These networks require specialized routing protocols due to their ad hoc nature. The performance of these protocols has been tested for the case of general traffic but not in respect with to multimedia traffic and especially video transmission. In this paper we conduct a number of simulations in order to evaluate the performance of three of the most popular routing protocols for MANETs and VANETs, namely AODV, DSR and OLSR, for different number of simultaneous video transmissions. We use the packet delivery ratio, the end-to-end delay, the packet delay variation (jitter) and the routing overhead as evaluation metrics. The results indicate that the DSR protocol outperforms AODV and OLSR in terms of end-to-end delay and packet delay variation and seems to be the most efficient routing protocol when multimedia traffic and especially video traffic is considered.1 aBouras, Christos1 aKapoulas, Vaggelis1 aGkamas, Apostolos1 aKioumourtzis, G1 aAdam, George1 aTavoularis, Nikos uhttps://telematics.upatras.gr/telematics/publications/performance-evaluation-routing-protocols-multimedia-transmission-over-mobile-ad-hoc?language=el01834nas a2200145 4500008004100000245011800041210006900159300001500228490000700243520121900250100002101469700002201490700002001512856015601532 2010 eng d00aAdaptive Smooth Multicast Protocol for Multimedia Transmission: Implementation Details and Performance Evaluation0 aAdaptive Smooth Multicast Protocol for Multimedia Transmission I a 299 - 3330 v233 a

In this article we propose a new single-rate multicast congestion control scheme named Adaptive Smooth Multicast Protocol (ASMP), for multimedia transmission over best-effort networks. The smoothness lays in the calculation and adaptation of the transmission rate, which is based on dynamic estimations of protocols? parameters and dynamic adjustment of the “smoothness factor”, as well. ASMP key attributes are: a) TCP-friendly behavior, b) adaptive scalability to large sets of receivers, c) high bandwidth utilization, and finally d) smooth transmission rates, which are suitable for multimedia applications. We evaluate the performance of ASMP and investigate its behavior under various network conditions through extensive simulations conducted with the network simulator software (ns2). Simulation results show that ASMP can be regarded as a serious competitor of TFMCC and PGMCC. In many cases, ASMP outperforms TFMCC in terms of TCP-friendliness and smooth transmission rates, while PGMCC presents lower scalability than ASMP. We have implemented ASMP on top of RTP/RTCP protocols in ns2 by adding all the RTP/RTCP protocol?s attributes that are defined in RFC 3550 and related to QoS metrics.

1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/adaptive-smooth-multicast-protocol-multimedia-transmission-implementation-details-and?language=el01355nas a2200145 4500008004100000245007400041210006900115260003400184300001300218520077900231100002101010700002201031700002001053856013601073 2010 eng d00aCross Layer Design for Multimedia Transmission over Wireless Networks0 aCross Layer Design for Multimedia Transmission over Wireless Net bInformation Science Reference a 35 - 423 a

Over the last years a number of new protocols have been developed for multimedia applications in the whole OSI layer?s scale. In addition wireless communications and networking fast occupy centre stage in research and development activity in the area of communication networks. In order to support better wireless user the cross layer design paradigm has been proposed. This chapter presents the challenges in design and implementation of cross layer adaptation schemes for multimedia transmission over wireless networks. In addition this chapter presents the most important parameters and constrains that should be taken into consideration when attempting cross layer adaptation in wireless networks that involves different protocols in the overall protocol stack.

1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/cross-layer-design-multimedia-transmission-over-wireless-networks?language=el01482nas a2200145 4500008004100000245010700041210006900148260001700217300001500234520087000249100002101119700002201140700002001162856015401182 2010 eng d00aPerformance Evaluation of MPEG-4 Video Transmission with the Adaptive Smooth Multicast Protocol (ASMP)0 aPerformance Evaluation of MPEG4 Video Transmission with the Adap cJune 22 - 25 a 540 - 5453 aWe present in this work the performance evaluation of MPEG-4 video transmission with our proposed single rate multicast protocol named Adaptive Smooth Multicast Protocol (ASMP). ASMP key attributes are: a) adaptive scalability to large sets of receivers, b) TCP- friendly behavior, c) high bandwidth utilization, and finally d) smooth transmission rates which are suitable for multimedia applications. We evaluate the performance of ASMP under an integrated simulation environment which extends ns-2 and Evalvid-RA to the multicast domain with the use of the RTP/RTCP protocols. Simulations conducted under this environment combine the measurements of network-centric along with video quality metrics. This “joint” evaluation process provides a better understanding of the benefits and limitations of any proposed protocol for multimedia data transmission.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/performance-evaluation-mpeg-4-video-transmission-adaptive-smooth-multicast-protocol?language=el01348nas a2200145 4500008004100000245006700041210006700108260001500175300001500190520080500205100002101010700002201031700002001053856012901073 2009 eng d00aAdaptive Smooth Simulcast Protocol for Multimedia Transmission0 aAdaptive Smooth Simulcast Protocol for Multimedia Transmission cJuly 5 - 8 a 437 - 4423 a

We introduce Adaptive Smooth Simulcast Protocol (ASSP) for simulcast transmission over best-effort networks. ASSP is a new multiple-rate protocol that implements a single rate TCP-friendly protocol as the underlying congestion control mechanism for each simulcast stream. ASSP is build on top of the RTP/RTCP protocol and exploits the RTCP sender and receiver reports for the dissemination of feedback information. The key attributes of ASSP are: a) TCPfriendly behavior, b) adaptive per-stream transmission rates, c) adaptive scalability to large sets of receivers and finally d) smooth transmission rates that are suitable for multimedia applications. We evaluate the performance of ASSP and investigate its behavior through simulations conducted with the network simulator software (ns2).

1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/adaptive-smooth-simulcast-protocol-multimedia-transmission?language=el01582nas a2200133 4500008004100000245009700041210006900138260001500207520100700222100002101229700002201250700002001272856015601292 2009 eng d00aEvaluation of Single Rate Multicast Congestion Control Schemes for MPEG-4 Video Transmission0 aEvaluation of Single Rate Multicast Congestion Control Schemes f cJuly 1 - 33 aWe present in this paper a simulation-based comparison of one of the best known multicast congestion control schemes - TFMCC - against our proposed Adaptive Smooth Multicast Protocol (ASMP). ASMP consists of a singlerate multicast congestion control, which takes advantage of the RTCP Sender (SR) and Receiver Reports (RR) in order to adjust the sender?s transmission rate in respect of the network conditions. The innovation in ASMP lays in the “smooth” transmission rate, which is TCP-friendly and prevent oscillations. We use an integrated simulation environment named Multi-Evalvid-RA for the evaluation of the two congestion control schemes. Multi-Evalvid-RA provides all the necessary tools to perform simulation studies and assess the video quality by using both network related metrics along with video quality measurements. The performance evaluation results show that ASMP is a very efficient solution for rate adaptive multimedia applications and a serious competitor to well know TFMCC.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/evaluation-single-rate-multicast-congestion-control-schemes-mpeg-4-video-transmission?language=el01914nas a2200145 4500008004100000245009100041210006900132260001800201300001200219520132100231100002101552700002201573700002001595856015301615 2009 eng d00aPerformance Evaluation of Simulcast vs. Layered Multicasting over Best-effort Networks0 aPerformance Evaluation of Simulcast vs Layered Multicasting over cSept. 24 - 26 a338-3483 aMulti-rate multicast schemes can be broadly classified into two categories. In layered multicast, a video file is transmitted by a base layer, which contains the most important features of the video. Additional layers, called enhancement layers, contain data that refine the quality of the base layer. In simulcast, the video file is transmitted by replicated layers that contain the same content at different quality. The benefits of layered multicast versus simulcast are still under question, as layered multicast presents higher complexity and more challenging deployment than simulcast. In this paper, two multirate multicast control schemes are compared. The layered multicast SMCC congestion control against our proposed solution for simulcast transmission, named ASSP. We compare the two schemes under a controlled simulation environment with the network simulator software (ns-2) by taking into account the evaluation criteria in RFC 5166. The results demonstrate that both SMCC and ASSP are TCP-friendly while SMCC seems to suffers from small oscillations of the transmission rate. In network topologies with low complexity ASSP consumes no more bandwidth than SMCC for the transmission of the different simulcast streams, while being a simpler solution than the more complicated SMCC.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/performance-evaluation-simulcast-vs-layered-multicasting-over-best-effort-networks?language=el01668nas a2200145 4500008004100000245011600041210006900157260001700226300001200243520104700255100002101302700002201323700002001345856015701365 2009 eng d00aSimulcast Transmission for Video Applications: Performance Evaluation with an Integrated Simulation Environment0 aSimulcast Transmission for Video Applications Performance Evalua cJuly 13 - 16 a339-3463 aThis paper presents the performance evaluation of a multi-rate multicast protocol named Adaptive Smooth Simulcast Protocol (ASSP) for simulcast video transmission. ASSP implements a single rate TCP-friendly protocol as the underlying congestion control mechanism for each simulcast stream. ASSP is built on top of the RTP/RTCP protocol and exploits the RTCP sender and receiver reports for the dissemination of feedback information. The key attributes of ASSP are: a) TCP-friendly behavior, b) adaptive per-stream transmission rates, c) adaptive scalability to large sets of receivers and finally d) smooth transmission rates that are suitable for multimedia applications. We evaluate the performance of ASSP under an integrated simulation environment, which extends ns-2 and Evalvid-RA into the multicast domain with the use of RTP/RTCP protocols. Simulations conducted under this environment combine the measurements of network metrics along with objective evaluation criteria on the perceived video quality by the end user.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/simulcast-transmission-video-applications-performance-evaluation-integrated-simulation?language=el01301nas a2200145 4500008004100000245008600041210006900127260001700196300001500213520071600228100002100944700002200965700002000987856014801007 2008 eng d00aAdaptive Smooth Multicast Congestion Control for Adaptive Multimedia Transmission0 aAdaptive Smooth Multicast Congestion Control for Adaptive Multim c16 - 18 June a 269 - 2763 aWe introduce Adaptive Smooth Multicast Protocol (ASMP), for multimedia transmission over best-effort networks. The smoothness lays in the calculation and adaptation of the transmission rate, which is based on dynamic estimation of protocol parameters and dynamic adjustment of the “smoothness factor”. ASMP key attributes are: a) adaptive scalability to large sets of receivers, b) TCP-friendly behavior, c) high bandwidth utilization, and finally d) smooth transmission rates, which are suitable for multimedia applications. We evaluate the performance of ASMP and investigate its behavior under various network conditions through extensive simulations, conducted with the network simulator software (ns2).1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/adaptive-smooth-multicast-congestion-control-adaptive-multimedia-transmission?language=el01505nas a2200145 4500008004100000245007800041210006900119260002100188300001200209520093600221100002101157700002201178700002001200856013901220 2008 eng d00aComparison of Single - Rate multicast Congestion Control protocol vs ASMP0 aComparison of Single Rate multicast Congestion Control protocol  c8 - 10 September a309-3163 a

We present in this paper a simulation-based comparison of two single-rate multicast congestion control schemes (TFMCC and PGMCC) against our proposed Adaptive Smooth Multicast Protocol (ASMP). ASMP consists of a single-rate multicast congestion control, which takes advantage of RTCP Sender (SR) and Receiver Reports (RR). The innovation in ASMP lays in the “smooth” transmission rate, which is TCP-friendly and prevent oscillations. The smooth behavior is naturally well suited to multimedia applications as high oscillations of the sending rate may create distortions of Audio-Video (AV) encoders and decoders. Simulation results, which are conducted with the network simulator ns2 software, showed that ASMP can be regarded as a serious competitor of TFMCC and PGMCC. In many cases, ASMP outperforms TFMCC in terms of TCP-friendliness and smooth transmission rates, while PGMCC presents lower scalability than ASMP.

1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/comparison-single-rate-multicast-congestion-control-protocol-vs-asmp?language=el01282nas a2200133 4500008004100000245009100041210006900132260001600201520071800217100002100935700002200956700002000978856015000998 2008 eng d00aExtending the Functionality of RTP/RTCP Implementation in Network Simulator (ns – 2)0 aExtending the Functionality of RTPRTCP Implementation in Network c3 - 7 March3 aIn this paper, we present a modification of the ns2 code for the RTP/RTCP protocols. The legacy RTP/RTCP code in ns2 has not yet been validated but it provides a framework of the protocol?s specification for experimental use. We have modified the code by adding all the RTP/RTCP protocol?s attributes that are defined in RFC 3550 and related to QoS metrics. We have also implemented additional algorithms and functions in order to enhance our modified code with TCP friendly bandwidth share behavior. Our protocol, named RTPUP (“UP” stands for the University of Patras), is offered as a package and is fully documented so that it can be used for simulations and research within the ns2 simulation environment.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/extending-functionality-rtprtcp-implementation-network-simulator-ns-%E2%80%93-2?language=el01406nas a2200133 4500008004100000245010300041210006900144260002900213520080900242100002101051700002201072700002001094856015801114 2008 eng d00aPerformance Evaluation of Cross Layer Adaptive Multimedia Transmission: The case of Wired Networks0 aPerformance Evaluation of Cross Layer Adaptive Multimedia Transm c28 September - 2 October3 aThis paper presents the performance evaluation of the wired part of a proposed framework with cross layer adaptation mechanisms, for multimedia transmission over wired and wireless networks. The performance evaluation of the proposed framework is contacted through a number of simulations with the network simulator software (ns2), which has been enhanced in order to support the functionality of the proposed framework. The performance evaluation includes various simulation scenarios in order to investigate the behavior of the proposed framework under different conditions. The proposed framework can support both wired and wireless receivers in one platform in which, cross layer information are used to support the wireless users whereas TCP friendly estimations are used to support the wired users.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/performance-evaluation-cross-layer-adaptive-multimedia-transmission-case-wired-networks?language=el01503nas a2200145 4500008004100000245007600041210006900117260001800186300001200204520094000216100002101156700002201177700002001199856013801219 2008 eng d00aSmooth Multicast Congstion Control for Adaptive Multimedia Transmission0 aSmooth Multicast Congstion Control for Adaptive Multimedia Trans c28 - 30 April a146-1523 aIn this paper we introduce an equation-based smooth multicast congestion control for adaptive multimedia transmission over best-effort wired networks. Target of the proposed schema is (a) smooth transmission rate, in order to minimize the Audio-Video (AV) encoding and decoding distortion and (b) TCP friendly transmission. The “smoothness” lays in the way the TCP-Friendly transmission rate is filtered. We integrate the congestion control functions in the RTP protocol and use the RTCP sender and receiver reports to provide the necessary feedback information for the sender?s adaptive transmission rate. The performance evaluation of the smooth adaptation and TCP-friendliness is conducted through a number of simulations with the network simulator software (ns2). Our intention is to use this congestion control in the context of a proposed framework for multimedia transmission over wired and wireless networks.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/smooth-multicast-congstion-control-adaptive-multimedia-transmission?language=el01321nas a2200145 4500008004100000245006900041210006900110260001500179300001500194520077500209100002100984700002201005700002001027856012801047 2007 eng d00aChallenges in cross layer adaptation for multimedia transmission0 aChallenges in cross layer adaptation for multimedia transmission c3 - 8 July a 129 - 1333 aOver the last years a number of new protocols have been developed for multimedia applications in the whole OSI layer?s scale. In order to support better wireless user the cross layer design paradigm has been proposed. This paper presents the challenges in designing and implementation of cross layer adaptation schemes for multimedia transmission over wired and wireless networks. In addition, the paper proposes the basic aspects of a cross-layer adaptation framework for multimedia transmission over wired and wireless networks. The main concept is based on a “holistic approach” in which all layers participate to the adaptation process and make its own contributions. Finally, the proposed framework can support both wired and wireless receivers in one platform.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/challenges-cross-layer-adaptation-multimedia-transmission?language=el01341nas a2200145 4500008004100000245010400041210006900145260001700214300001500231520073500246100002100981700002201002700002001024856015101044 2007 eng d00aA Framework for Cross Layer Adaptation for Multimedia Transmission over Wired and Wireless Networks0 aFramework for Cross Layer Adaptation for Multimedia Transmission c25 - 28 June a 153 - 1593 aThis paper proposes a framework for cross-layer adaptation for multimedia transmission over wired and wireless networks. The proposed framework consists of four entities: The sender, the proxy, which is located at the edge of the wired network, the access point, which co-located with the proxy and finally the wired and wireless receivers. The main concept is based on a “holistic approach” in which all layers participate to the adaptation process and make its own contributions. In addition, the proposed framework can support both wired and wireless receivers in one platform and cross layer information are used in order to support wireless users whereas TCP friendly estimations are used in order to support wired users.1 aBouras, Christos1 aGkamas, Apostolos1 aKioumourtzis, G uhttps://telematics.upatras.gr/telematics/publications/framework-cross-layer-adaptation-multimedia-transmission-over-wired-and-wireless?language=el