Prawit Chumchu

A new MAC address spoofing detection algorithm using PLCP header

This paper presents a new MAC (Medium Access Control) spoofing detection algorithm in IEEE 802.11 networks. The proposed algorithm utilizes PLCP (Physical Layer Convergence Protocol) header of IEEE 802.11 frames to differentiate an attacker station from a genuine station. PLCP header of IEEE 802.11 frames maybe change for each frame. It depends on transmission rate adaptation algorithm which is designed by vendors of wireless interfaces driver. The rate adaptation of an attacker station and a genuine station is different depending on adaptive algorithm and environments; therefore it is much harder to forge PLCP header. The experimental results show that the percent of correct detection is 100 percent when the number of monitoring stations located in appropriate positions are only two.

The reduction of gradient noise in gradient-based algorithm by using variable step-size technique

This paper proposes a different approach to control step-size adaptation. The objective is to ensure large step-size when the algorithm is far from the optimum with step-size decreasing as we approach the optimum. The proposed algorithm achieves this objective by employing the output signal energy to control step-size update. In the early stage of adaptation the estimate of the output signal energy is large, resulting in a large step-size. As we approach the optimal, the output signal energy approaches zero, resulting in a small step-size. This provides the fast convergence due to large initial step-size while ensuring low gradient noise due to the small final step-size, resulting in low variance of the filter coefficient.

Simplify adaptive IIR notch filter based on least mean p-power error criterion

In this paper, a simplify second order IIR adaptive notch (ANF) algorithm based on least mean p-power (LMP) error criterion is presented. The quantizing gradient technique is used to detect high convergence speed and high impulsive noise robustness. This algorithm reduces an amount of multiplication computational equal to the length of input data. It is proved here that the convergence speed, variance, bias and noise robustness do not depend on p values. For practical application with most desirable purposes, the value of p=1 is chosen, the results of computer simulation and application on TMS320C50 digital signal processing starter kit are given to demonstrate the convergence speed and noise robustness performance.

Design and implementation of micro mobile MPLS for NS-2

In this paper, we extend NS-2 to simulate Micro-Mobile MPLS frameworks. The extension supports most of the important mechanisms used in the literature. The simulator is based on IEEE 802.11. The important mechanisms for IEEE 802.11 in our module are multi-channel, directional antennas, multiple interfaces, L2-handoff, L2-trigger, bicasting, pre-established LSP, and buffering mechanism. MPLS modules used in this simulator is based on MPLS module (MNS) [8]-[10]. This simulator could be configured to assess performance of Mobile MPLS protocols such as micro mobility-enabled multiprotocol label switching (M-MPLS) [21], fast handoff (FH) and master forwarding chain (MFC)-Micro Mobile MPLS [2], [23] and MiM-MPLS [30]. The simulator is validated for each mechanism. The validation results follow to the theory.

A Model-Based Scalable Reliable Multicast Transport Protocol for Wireless/Mobile Networks

In this paper, we propose the design of a scalable reliable mobile multicast scheme-SRMoM. SRMoM uses well-known Scalable Reliable Multicast (SRM) in the wired networks and a NAK-based ARQ with adaptive Forward Error Correction (AFEC) in the wireless networks. In AFEC, the probability of needing retransmission of original multicast packets after FEC recovery is selectable. This selective property enables the control of channel utilization in the wireless segment for different numbers of Mobile Hosts (MHs). Using this property, the channel utilization of SRMoM is made to be virtually independent of the number of MHs, thus making it extremely scalable. The performance of SRMoM is analyzed with three adaptive FEC algorithms based on three wireless loss models, namely a Gilbert-Elliott channel, a simplified Cilbert-Elliott channel, and a binary symmetric channel, analytically as well as through simulation. Furthermore, the performance of SRMoM is compared with SRM and MRMoM (NAK-based protocol without FEC) through simulation. Using the average number of transmissions per original multicast packet, and wireless link utilization as metrics, we demonstrate that the performance of SRMoM is indeed virtually independent of the number of MHs, and that it results in the lowest number of packet transmissions and lowest channel utilization of reliable mobile multicast protocols thai have been proposed to date.

Performance analysis of reliable multicast transport protocols for GEO satellite networks

We present a comparison of reliable multicast transport protocols for GEO satellite networks. The performance is analyzed using the general design principle of end-to-end transport protocols, mathematical model and simulation model. The mathematical model is used to present approximated performance. The simulator is implemented to support 3 types of medium access control protocols and 3 types of loss models. We consider 3 end-to-end reliable multicast transport protocols. These protocols present most of the reliable multicast transport protocol design issues for satellite networks, such as forward error correction, congestion control, feedback control, feedback adaptation. Our goal is to understand the performance in several aspects of reliable multicast transport protocols in different environments.

Mobile MPLS with route optimization: The proposed protocol and simulation study

Mobile MPLS, as the integration of Mobile IP and MPLS (Multiprotocol Label Switching), has the benefits of having mobility support from Mobile IP and quality of service support from MPLS. These benefits are important to mobile networks carrying various Internet services to mobile users. Nevertheless, Mobile MPLS inherits a problem of routing inefficiency called triangle routing from Mobile IP. This paper proposes a route optimization protocol to overcome this problem in Mobile MPLS. By adding a correspondent agent function to Mobile MPLSs edge routers, the mobility binding of a mobile node can be cached by the edge routers and the packet routing to the mobile node can be route-optimized. We evaluate our proposal by implementing it on the Network Simulator (NS-2). The simulation results indicate that the proposed route optimization has improved the performance of Mobile MPLS by reducing its end-to-end delay.

Mobility support in private networks using RPX

The limited IPv4 address space has driven the cellular industry to start using IPv6 addresses for mobile users in 3G-networks. However, there is a potential threat to the success of 3G-network deployment, as the success will depend on the services offering to the end users. Currently, the overwhelming proportion of services resides in the IPv4 address space, which makes them inaccessible to users in the IPv6 address space. Thus, users cannot directly communicate with and access services without an intermediate translation mechanism. Previous studies on network address translation methods have shown that REBEKAH-IP with Port Extension, RPX is promising in that it provides excellent theoretical maximum scalability while supporting all types of services without limitations for the users in the network. However, the initial RPX proposal does not support host mobility to different networks, despite the fact that mobility is the most important feature of a wireless communication system. In this paper, we propose to extend the RPX scheme with a mobility support scheme based on mobile IP. RPX allows more than one host to use a single IPv4 address and therefore we have augmented Mobile IP with a new tunneling mechanism called IP-in-FQDN tunneling. The mechanism allows for unique mapping despite the sharing of IP addresses while maintaining the scalability of RPX. In addition, we present simulation results that indicate that the proposed scheme performs well in terms of scalability, connection request delay and packet transmission delay compared to mobile IP

Convergence speed improvement for a variable step-size plain gradient algorithm by using variable notch bandwidth technique

A novel adaptive algorithm for a second order adaptive lattice notch filter is represented. It is established based on a robust variable step-size plain gradient algorithm (VSPG) and the proposed time-varying notch bandwidth technique. This technique can improve the convergence speed of the VSPG up to many times. The time-varying notch bandwidth is adjusted to be wide when the algorithm is far from the optimum. As algorithm approaches the optimum, the notch bandwidth is automatically adjusted to be narrow. In the early stage of adaptation, the proposed algorithm has high speed due to the wide bandwidth while ensuring high accuracy in the desired parameter due to the final narrow bandwidth. Extensive simulations are provided to show the performances of the novel adaptive algorithm. In addition, the coefficient bias and mean square error (MSE) are also revealed.

Performance analysis and improvement of mobile MPLS

This paper proposes a new protocol to integrate the Mobile IP and MPLS protocols called B-MPLS. The proposed protocol is based on L2 information and a simple buffer technique. Performance analysis of proposed protocol is simulated by the Network Simulator (NS2). The primarily results show that the proposed mechanism grants seamless handover. The packet lost rate is much lower than that of mobile MPLS without buffering.