The Experts below are selected from a list of 49431 Experts worldwide ranked by ideXlab platform
Shivendra S Panwar - One of the best experts on this subject based on the ideXlab platform.
-
mrtp a multiflow real time Transport Protocol for ad hoc networks
IEEE Transactions on Multimedia, 2006Co-Authors: Shiwen Mao, Dennis Bushmitch, Sathya Narayanan, Shivendra S PanwarAbstract:Real-time multimedia Transport has stringent quality of service requirements, which are generally not supported by current network architectures. In emerging mobile ad hoc networks, frequent topology changes and link failures cause severe packet losses, which degrade the quality of received media. However, in such mesh networks, there usually exist multiple paths between any source and destination nodes. Such path diversity has been demonstrated to be effective in combating congestion and link failures for improved media quality. In this paper, we present a new Protocol to facilitate multipath Transport of real-time multimedia data. The proposed Protocol, the multiflow real-time Transport Protocol (MRTP), provides a convenient vehicle for real-time applications to partition and transmit data using multiple flows. We demonstrate through analysis that data partitioning, which is an essential function of MRTP, can effectively reduce the short-range dependence of multimedia data, thus improving its queueing performance in underlying networks. Furthermore, we show that a few flows are sufficient for MRTP to exploit most of the benefits of multipath Transport. Finally, we present a comprehensive simulation study on the performance of MRTP under a mobile ad hoc network. We show that with one additional path, MRTP outperformed single-flow RTP by a significant margin.
Li Gui - One of the best experts on this subject based on the ideXlab platform.
-
a conditional retransmission enabled Transport Protocol for real time networked control systems
Local Computer Networks, 2011Co-Authors: Li Gui, Yuchu Tian, Colin J FidgeAbstract:Real-time networked control systems (NCSs) over data networks are being increasingly implemented on a massive scale in industrial applications. Along with this trend, wireless network technologies have been promoted for modern wireless NCSs (WNCSs). However, popular wireless network standards such as IEEE 802.11/15/16 are not designed for real-time communications. Key issues in real-time applications include limited transmission reliability and poor transmission delay performance. Considering the unique features of real-time control systems, this paper develops a conditional retransmission enabled Transport Protocol (CRETP) to improve the delay performance of the transmission control Protocol (TCP) and also the reliability performance of the user datagram Protocol (UDP) and its variants. Key features of the CRETP include a connectionless mechanism with acknowledgment (ACK), conditional retransmission and detection of ineffective data packets on the receiver side.
-
a Transport Protocol for real time applications in wireless networked control systems
2010Co-Authors: Li GuiAbstract:A Networked Control System (NCS) is a feedback-driven control system wherein the control loops are closed through a real-time network. Control and feedback signals in an NCS are exchanged among the system’s components in the form of information packets via the network. Nowadays, wireless technologies such as IEEE802.11 are being introduced to modern NCSs as they offer better scalability, larger bandwidth and lower costs. However, this type of network is not designed for NCSs because it introduces a large amount of dropped data, and unpredictable and long transmission latencies due to the characteristics of wireless channels, which are not acceptable for real-time control systems. Real-time control is a class of time-critical application which requires lossless data transmission, small and deterministic delays and jitter. For a real-time control system, network-introduced problems may degrade the system’s performance significantly or even cause system instability. It is therefore important to develop solutions to satisfy real-time requirements in terms of delays, jitter and data losses, and guarantee high levels of performance for time-critical communications in Wireless Networked Control Systems (WNCSs). To improve or even guarantee real-time performance in wireless control systems, this thesis presents several network layout strategies and a new Transport layer Protocol. Firstly, real-time performances in regard to data transmission delays and reliability of IEEE 802.11b-based UDP/IP NCSs are evaluated through simulations. After analysis of the simulation results, some network layout strategies are presented to achieve relatively small and deterministic network-introduced latencies and reduce data loss rates. These are effective in providing better network performance without performance degradation of other services. After the investigation into the layout strategies, the thesis presents a new Transport Protocol which is more effcient than UDP and TCP for guaranteeing reliable and time-critical communications in WNCSs. From the networking perspective, introducing appropriate communication schemes, modifying existing network Protocols and devising new Protocols, have been the most effective and popular ways to improve or even guarantee real-time performance to a certain extent. Most previously proposed schemes and Protocols were designed for real-time multimedia communication and they are not suitable for real-time control systems. Therefore, devising a new network Protocol that is able to satisfy real-time requirements in WNCSs is the main objective of this research project. The Conditional Retransmission Enabled Transport Protocol (CRETP) is a new network Protocol presented in this thesis. Retransmitting unacknowledged data packets is effective in compensating for data losses. However, every data packet in realtime control systems has a deadline and data is assumed invalid or even harmful when its deadline expires. CRETP performs data retransmission only in the case that data is still valid, which guarantees data timeliness and saves memory and network resources. A trade-off between delivery reliability, transmission latency and network resources can be achieved by the conditional retransmission mechanism. Evaluation of Protocol performance was conducted through extensive simulations. Comparative studies between CRETP, UDP and TCP were also performed. These results showed that CRETP significantly: 1). improved reliability of communication, 2). guaranteed validity of received data, 3). reduced transmission latency to an acceptable value, and 4). made delays relatively deterministic and predictable. Furthermore, CRETP achieved the best overall performance in comparative studies which makes it the most suitable Transport Protocol among the three for real-time communications in a WNCS.
Kang Won Lee - One of the best experts on this subject based on the ideXlab platform.
-
Cross-layer path management in multi-path Transport Protocol for mobile devices
Proceedings - IEEE INFOCOM, 2014Co-Authors: Yeon Sup Lim, Yung-chih Chen, Erich M. Nahum, Don Towsley, Kang Won LeeAbstract:MPTCP is a new Transport Protocol that enables mobile devices to use several physical paths simultaneously through multiple network interfaces, such as WiFi and cellular. However, wireless path characteristics change frequently in mobile environments, causing challenges for MPTCP: For example, WiFi associated paths often become unavailable as devices move, since WiFi has intermittent connectivity caused by the short signal range and susceptibility to interference. In this work, we improve MPTCP to manage path usage based on the associated link status. This variant, called MPTCP-MA, uses MAC-Layer information to locally estimate path quality and connectivity. By suspending/releasing paths based on their quality, MPTCP-MA can more effectively utilize restored paths. We have implemented and deployed MPTCP-MA in Linux and Android. Our experimental results show that MPTCP-MA can efficiently utilize an intermittently available path, with Wifi throughput improvements of up to 72 percent.
Shiwen Mao - One of the best experts on this subject based on the ideXlab platform.
-
mrtp a multiflow real time Transport Protocol for ad hoc networks
IEEE Transactions on Multimedia, 2006Co-Authors: Shiwen Mao, Dennis Bushmitch, Sathya Narayanan, Shivendra S PanwarAbstract:Real-time multimedia Transport has stringent quality of service requirements, which are generally not supported by current network architectures. In emerging mobile ad hoc networks, frequent topology changes and link failures cause severe packet losses, which degrade the quality of received media. However, in such mesh networks, there usually exist multiple paths between any source and destination nodes. Such path diversity has been demonstrated to be effective in combating congestion and link failures for improved media quality. In this paper, we present a new Protocol to facilitate multipath Transport of real-time multimedia data. The proposed Protocol, the multiflow real-time Transport Protocol (MRTP), provides a convenient vehicle for real-time applications to partition and transmit data using multiple flows. We demonstrate through analysis that data partitioning, which is an essential function of MRTP, can effectively reduce the short-range dependence of multimedia data, thus improving its queueing performance in underlying networks. Furthermore, we show that a few flows are sufficient for MRTP to exploit most of the benefits of multipath Transport. Finally, we present a comprehensive simulation study on the performance of MRTP under a mobile ad hoc network. We show that with one additional path, MRTP outperformed single-flow RTP by a significant margin.
Colin J Fidge - One of the best experts on this subject based on the ideXlab platform.
-
a conditional retransmission enabled Transport Protocol for real time networked control systems
Local Computer Networks, 2011Co-Authors: Li Gui, Yuchu Tian, Colin J FidgeAbstract:Real-time networked control systems (NCSs) over data networks are being increasingly implemented on a massive scale in industrial applications. Along with this trend, wireless network technologies have been promoted for modern wireless NCSs (WNCSs). However, popular wireless network standards such as IEEE 802.11/15/16 are not designed for real-time communications. Key issues in real-time applications include limited transmission reliability and poor transmission delay performance. Considering the unique features of real-time control systems, this paper develops a conditional retransmission enabled Transport Protocol (CRETP) to improve the delay performance of the transmission control Protocol (TCP) and also the reliability performance of the user datagram Protocol (UDP) and its variants. Key features of the CRETP include a connectionless mechanism with acknowledgment (ACK), conditional retransmission and detection of ineffective data packets on the receiver side.
