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IJAHUC. 01/2009; 4:54-60.
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INFOCOM 2007. 26th IEEE International Conference on Computer Communications, Joint Conference of the IEEE Computer and Communications Societies, 6-12 May 2007, Anchorage, Alaska, USA; 01/2007
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ABSTRACT: The IEEE 802.11 standard for wireless local area networks (WLANs) employs a medium access control (MAC), called distributed coordination function (DCF), which is based on carrier sense multiple access with collision avoidance (CSMA/CA). The collision avoidance mechanism utilizes the random backoff prior to each frame transmission attempt. The random nature of the backoff reduces the collision probability, but cannot completely eliminate collisions. It is known that the throughput performance of the 802.11 WLAN is significantly compromised as the number of stations increases. In this paper, we propose a novel distributed reservation-based MAC protocol, called early backoff announcement (EBA), which is backward compatible with the legacy DCF. Under EBA, a station announces its future backoff information in terms of the number of backoff slots via the MAC header of its frame being transmitted. All the stations receiving the information avoid collisions by excluding the same backoff duration when selecting their future backoff value. Through extensive simulations, EBA is found to achieve a significant increase in the throughput performance as well as a higher degree of fairness compared to the 802.11 DCF.
IEEE Transactions on Mobile Computing 08/2005; 4(4):378- 390. · 2.28 Impact Factor
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ABSTRACT: An entire network can be managed as a single mobility entity when it moves as a unit. To support network mobility (NEMO), a mobile router has been introduced to manage the mobility of whole nodes inside the network. In this mobile network, multiple mobile router (MR)s and home agent (HA)s scenarios are considered to provide reliability and load sharing. In this paper, we present a neighbor MR authentication and registration mechanism in multihomed mobile networks. Also, using registered MRs, we propose a HA-based dynamic load sharing mechanism. Using measured latency from periodic binding update (BU) messages, the HA shares traffic load with an alternative tunnel. Our proposed mechanism requires no additional signaling messages except some options in the BU message.
Communications, 2005. ICC 2005. 2005 IEEE International Conference on; 06/2005
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Information Networking, Convergence in Broadband and Mobile Networking, International Conference, ICOIN 2005, Jeju Island, Korea, January 31- February 2, 2005, Proceedings; 01/2005
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Personal Wireless Communications, IFIP TC6 9th International Conference, PWC 2004, Delft, The Netherlands, September 21-23, 2004, Proceedings; 01/2004
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ABSTRACT: Wireless data services are fundamental in ubiquitous networks. In wireless data networks, the TCP congestion mechanism can mistake a wireless channel error or blackout for congestion on the route. Several wireless TCP protocols have been proposed considering TCP performance degradation in wireless systems.
07/2003;
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ABSTRACT: Neighbour knowledge in mobile ad hoc networks provides important functionality for a number of protocols. An approach where each node acquires neighbour knowledge by observing not only hello packets but also flooded packets is presented. Analysis results show that this method offers significant improvement over the original scheme.
Electronics Letters 06/2003; · 0.96 Impact Factor
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Information Networking, Networking Technologies for Enhanced Internet Services International Conference, ICOIN 2003, Cheju Island, Korea, February 12-14, 2003, Revised Selected Papers; 01/2003
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ABSTRACT: Cyclic best-effort multicast supports reliable multicast transport by sending information repeatedly. The authors present forward error correcting (FEC) cyclic best-effort multicast which transmits FEC encoded redundant data as well as original data. FEC cyclic multicasting reduces the number of packet transmissions at least by half compared to plain cyclic multicasting.
03/2002;
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ABSTRACT: The Impatient variant of TCP NewReno responds to partial ACKs more
aggressively than the Slow-but-Steady variant. Because the Impatient
variant invokes Slow Start, its loss recovery time depends on the
pattern of packet drops. Here, the average loss recovery time of the
Impatient variant of NewReno is analysed
Electronics Letters 01/2002; · 0.96 Impact Factor
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Networking - ICN 2001, First International Conference, Colmar, France, July 9-13, 2001 Proceedings, Part 2; 01/2001
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ABSTRACT: This paper deals with the TCP bandwidth guarantee problem in a Differentiated Services (Diffserv) network. Several researches
proposed a RIO mechanism for the assured service. In RIO, IN packets experience lower drop probability than OUT packets to
guarantee the promised bandwidth even under network congestion. However a token bucket marker fails to provide adequate performance
to TCP connections because TCP generates bursty packets due to the unique TCP congestion control mechanism. We propose a new
marker that uses a data buffer as well as a token buffer. The marker with a data buffer works well with RIO because it smooths
TCP traffic. We show that the marker with a data buffer achieves the target throughput better than a marker with a token buffer
only. We also show that the optimal data buffer size is proportional to reserved throughput and RTT.
12/2000: pages 61-70;
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ABSTRACT: A new congestion control scheme denoted the instantaneous variant
of NewReno is proposed. In this method, a sender instantly enters into
the slow start phase when it receives the first partial ACK during the
fast recovery phase. Performance evaluation shows that the instantaneous
variant of NewReno expedites packet loss recovery and increases the
throughput
Electronics Letters 10/2000; · 0.96 Impact Factor
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ABSTRACT: Wireless data services are fundamental in ubiquitous networks. In wireless data networks, the TCP congestion mechanism can mistake a wireless channel error or blackout for congestion on the route. Several wireless TCP protocols have been proposed considering TCP performance degradation in wireless systems. However, these protocols are too complex to deploy in wireless systems. In this paper, we propose the ACK Pacing algorithm for long lasting loss periods like a hand-off or a blackout. By pacing ACK packets sending, we prevent bursty data delivery to the old path and a spurious timeout occurrence. Also, paced ACK packets trigger the route update to the new path faster. The proposed algorithm can be implemented in the wireless-node-side which is easily applicable to wireless systems. From simulation results, ACK Pacing improves TCP performance compared with many TCP variations. The ACK Pacing algorithm shows good performance during a long lasting loss period.
