The fundamental access mode of the IEEE 802.11 MAC protocol is contention based. If the traffic l... more The fundamental access mode of the IEEE 802.11 MAC protocol is contention based. If the traffic load is heavy or the number of contending station is large, the number of collisions is increased and it leads to the performance degradation. In this paper, we propose a mechanism that tries to reduce the number of collisions by separating and grouping the
As handoff latency increases, mobile hosts experience performance and service quality degradation... more As handoff latency increases, mobile hosts experience performance and service quality degradations. Typically, it gives a significant impact on the performance of real-time multimedia applications. In this paper, an efficient handoff mechanism that reduces the handoff latency in HMIPv6 is proposed. In the proposed handoff mechanism, each access router learns its neighboring access router information. For this, a neighbor access router discovery scheme is proposed. When a mobile host senses that it will perform a handoff to a new network, it performs an Address Auto-configuration procedure for its LCoA (RCoA and LCoA in case of the handoff to a new MAP domain) in advance using the neighbor access router information received from the current access router. These features give us the reduction of latency both in intra-MAP and inter-MAP handoffs. The simulation results using ns-2 show that the proposed handoff mechanism reduces handoff latency.
This paper presents a bidirectional data transfer protocol to improve the capacity and throughput... more This paper presents a bidirectional data transfer protocol to improve the capacity and throughput in wireless local area networks (WLANs). By reducing the number of contentions among stations as much as possible, a large portion of time wasted for contentions can be used for actual data transfer. The approach proposed in this paper assumes a multi-rate WLANs environment where a
... Therefore, it is necessary to find out the method to reduce a handover latency. For this reas... more ... Therefore, it is necessary to find out the method to reduce a handover latency. For this reason,Fast Handovers for Mobile IPv6 (FMIPv6) protocol has been proposed to reduce the MIPv6 ... it tries to acquire a new CoA (NCoA) in the manner of stateless [4] or stateful (eg DHCPv6 [5 ...
The 7th International Conference on Advanced Communication Technology, 2005, ICACT 2005., 2005
Recently, motivated by users demands for higher mobility and bandwidth, there are active research... more Recently, motivated by users demands for higher mobility and bandwidth, there are active researches on 4G systems. The requirements of 4G systems are all-IP based networks with cellular architecture and IP mobility supports to users. In this network, the L2 handoff scheme should be designed carefully and consider the L3 handoff scheme to reduce the handoff latency. The L2 and L3 handoff schemes in current wireless networks are performed separately, keeping the layer independence, which results in longer handoff latency. In this paper, we analyze handoff schemes of current wireless networks and design the handoff scheme for a 4G system including a handoff detection method. An integration method of the FMIPv6 protocol with the proposed L2 handoff scheme is also proposed, which can reduce the handoff latency and the number of control messages exchanged between the MN and the network
Sixth IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks
There has been much research effort to exploit the multi-rate capability of WLANs to improve perf... more There has been much research effort to exploit the multi-rate capability of WLANs to improve performance. While these approaches focused on exploiting good channel conditions for direct transmission between stations, there are no considerations of performance degradation by low rate transmissions due to poor channel conditions. Thus, we propose a frame relay based MAC protocol, termed FR-MAC, to tackle this issue and to improve network performance. The key idea of FR-MAC is that the time required to transmit a frame using an intermediate station as a relay can be much smaller than the direct transmission at a lower rate, if the intermediate station between the source and the receiver can relay the frame at higher rates. Simulation results show that the proposed protocol improves network performance and the amount of improvement significantly increases as the number of relayed stations and the payload size are increased.
... Chapter 5. Performance Analysis of Wireless Ad Hoc Networks Anurag Kumar, Aditya Karnik Abstr... more ... Chapter 5. Performance Analysis of Wireless Ad Hoc Networks Anurag Kumar, Aditya Karnik Abstract - Hi-Res PDF (398 KB) - PDF ... Structured Proactive and Reactive Routing for Wireless Mobile Ad Hoc Networks Ahmed M. Safwat, Hossam S. Hassane, Hussein T. Mouftah ...
Providing multicast service to mobile hosts in wireless mobile networking environments is difficu... more Providing multicast service to mobile hosts in wireless mobile networking environments is difficult due to frequent changes of mobile host location and group membership. If a conventional multicast routing protocol is used in wireless mobile networks, several problems may be experienced since existing multicast routing protocols assume static hosts when they construct the multicast delivery tree. To overcome the problems,
Proceedings 2000 International Conference on Parallel Processing
Providing multicast service to mobile hosts is difficult due to frequent changes of mobile host l... more Providing multicast service to mobile hosts is difficult due to frequent changes of mobile host location and group membership. To overcome the difficulty, several multicast protocols for mobile hosts have been proposed. Although the protocols solve several problems inherent in multicast routing proposals for static hosts, they still have problems such as non-optimal delivery path, datagram duplication, etc. In this paper, we summarize these problems of multicast routing protocols and propose an efficient multicast protocol using a multicast agent in wireless mobile networks, where a mobile host receives a tunneled multicast datagram from a multicast agent located in a network close to it or directly from the multicast router in the current network. While receiving a tunneled multicast datagram from a remote multicast agent, the local multicast agent starts multicast join process, which makes the multicast delivery route optimal. The proposed protocol reduces data delivery path length and decreases not only the amount of duplicate copies of multicast datagrams but also multicast traffic load. We examined and compared the performance of the proposed protocol and existing protocols by simulation under various environments and we got an improved performance over the existing proposals
As the increase of wireless network applications based on TCP/IP, many researchers have been tryi... more As the increase of wireless network applications based on TCP/IP, many researchers have been trying to develop TCP according to wireless environments. However, most of the proposed schemes do not consider the multi-rate capability of WLANs. In this paper, through experiments in 802.11b WLAN based multi-rate environments having data rates of 2Mbps, 5Mbps, and 11Mbps, we show that total throughput
The fundamental access mode of the IEEE 802.11 MAC protocol is contention based. If the traffic l... more The fundamental access mode of the IEEE 802.11 MAC protocol is contention based. If the traffic load is heavy or the number of contending station is large, the number of collisions is increased and it leads to the performance degradation. In this paper, we propose a mechanism that tries to reduce the number of collisions by separating and grouping the
As handoff latency increases, mobile hosts experience performance and service quality degradation... more As handoff latency increases, mobile hosts experience performance and service quality degradations. Typically, it gives a significant impact on the performance of real-time multimedia applications. In this paper, an efficient handoff mechanism that reduces the handoff latency in HMIPv6 is proposed. In the proposed handoff mechanism, each access router learns its neighboring access router information. For this, a neighbor access router discovery scheme is proposed. When a mobile host senses that it will perform a handoff to a new network, it performs an Address Auto-configuration procedure for its LCoA (RCoA and LCoA in case of the handoff to a new MAP domain) in advance using the neighbor access router information received from the current access router. These features give us the reduction of latency both in intra-MAP and inter-MAP handoffs. The simulation results using ns-2 show that the proposed handoff mechanism reduces handoff latency.
This paper presents a bidirectional data transfer protocol to improve the capacity and throughput... more This paper presents a bidirectional data transfer protocol to improve the capacity and throughput in wireless local area networks (WLANs). By reducing the number of contentions among stations as much as possible, a large portion of time wasted for contentions can be used for actual data transfer. The approach proposed in this paper assumes a multi-rate WLANs environment where a
... Therefore, it is necessary to find out the method to reduce a handover latency. For this reas... more ... Therefore, it is necessary to find out the method to reduce a handover latency. For this reason,Fast Handovers for Mobile IPv6 (FMIPv6) protocol has been proposed to reduce the MIPv6 ... it tries to acquire a new CoA (NCoA) in the manner of stateless [4] or stateful (eg DHCPv6 [5 ...
The 7th International Conference on Advanced Communication Technology, 2005, ICACT 2005., 2005
Recently, motivated by users demands for higher mobility and bandwidth, there are active research... more Recently, motivated by users demands for higher mobility and bandwidth, there are active researches on 4G systems. The requirements of 4G systems are all-IP based networks with cellular architecture and IP mobility supports to users. In this network, the L2 handoff scheme should be designed carefully and consider the L3 handoff scheme to reduce the handoff latency. The L2 and L3 handoff schemes in current wireless networks are performed separately, keeping the layer independence, which results in longer handoff latency. In this paper, we analyze handoff schemes of current wireless networks and design the handoff scheme for a 4G system including a handoff detection method. An integration method of the FMIPv6 protocol with the proposed L2 handoff scheme is also proposed, which can reduce the handoff latency and the number of control messages exchanged between the MN and the network
Sixth IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks
There has been much research effort to exploit the multi-rate capability of WLANs to improve perf... more There has been much research effort to exploit the multi-rate capability of WLANs to improve performance. While these approaches focused on exploiting good channel conditions for direct transmission between stations, there are no considerations of performance degradation by low rate transmissions due to poor channel conditions. Thus, we propose a frame relay based MAC protocol, termed FR-MAC, to tackle this issue and to improve network performance. The key idea of FR-MAC is that the time required to transmit a frame using an intermediate station as a relay can be much smaller than the direct transmission at a lower rate, if the intermediate station between the source and the receiver can relay the frame at higher rates. Simulation results show that the proposed protocol improves network performance and the amount of improvement significantly increases as the number of relayed stations and the payload size are increased.
... Chapter 5. Performance Analysis of Wireless Ad Hoc Networks Anurag Kumar, Aditya Karnik Abstr... more ... Chapter 5. Performance Analysis of Wireless Ad Hoc Networks Anurag Kumar, Aditya Karnik Abstract - Hi-Res PDF (398 KB) - PDF ... Structured Proactive and Reactive Routing for Wireless Mobile Ad Hoc Networks Ahmed M. Safwat, Hossam S. Hassane, Hussein T. Mouftah ...
Providing multicast service to mobile hosts in wireless mobile networking environments is difficu... more Providing multicast service to mobile hosts in wireless mobile networking environments is difficult due to frequent changes of mobile host location and group membership. If a conventional multicast routing protocol is used in wireless mobile networks, several problems may be experienced since existing multicast routing protocols assume static hosts when they construct the multicast delivery tree. To overcome the problems,
Proceedings 2000 International Conference on Parallel Processing
Providing multicast service to mobile hosts is difficult due to frequent changes of mobile host l... more Providing multicast service to mobile hosts is difficult due to frequent changes of mobile host location and group membership. To overcome the difficulty, several multicast protocols for mobile hosts have been proposed. Although the protocols solve several problems inherent in multicast routing proposals for static hosts, they still have problems such as non-optimal delivery path, datagram duplication, etc. In this paper, we summarize these problems of multicast routing protocols and propose an efficient multicast protocol using a multicast agent in wireless mobile networks, where a mobile host receives a tunneled multicast datagram from a multicast agent located in a network close to it or directly from the multicast router in the current network. While receiving a tunneled multicast datagram from a remote multicast agent, the local multicast agent starts multicast join process, which makes the multicast delivery route optimal. The proposed protocol reduces data delivery path length and decreases not only the amount of duplicate copies of multicast datagrams but also multicast traffic load. We examined and compared the performance of the proposed protocol and existing protocols by simulation under various environments and we got an improved performance over the existing proposals
As the increase of wireless network applications based on TCP/IP, many researchers have been tryi... more As the increase of wireless network applications based on TCP/IP, many researchers have been trying to develop TCP according to wireless environments. However, most of the proposed schemes do not consider the multi-rate capability of WLANs. In this paper, through experiments in 802.11b WLAN based multi-rate environments having data rates of 2Mbps, 5Mbps, and 11Mbps, we show that total throughput
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