Multiple IEEE Research Articles

On Striping Traffic over Multiple IEEE 802.11(b) Wireless Channels

Due to interference, path loss, multipath fading, background noise, and many other factors, wireless communication normally cannot provide a wireless link with both a high data rate and a long transmission range. To address this problem, striping network traffic in parallel over multiple lower-data-rate but longer-transmission-range wireless channels may be used. In this paper, we propose a new striping method and evaluate its performances over multiple IEEE 802.11(b) channels under various conditions. Our extensive simulation results show that this method is quite effective for such an application.

Design and performance of an enhanced IEEE 802.11 MAC protocol for multihop coverage extension

Ad hoc communication is gaining popularity, not only for pure ad hoc communication networks but also as a viable solution for coverage extension in wireless networks. Especially for upcoming WLAN hotspots, this is an interesting option to decrease installation costs. In this article we introduce a new MAC protocol that needs only marginal changes to the standard and enables efficient multihop networking. We advocate the use of multiple IEEE 802.11 channels, where one channel is reserved as a common signalling channel for the task of assigning the others (data channels) among wireless terminals. The proposed MAC protocols are based on a four-way handshake over the common signalling channel, while data transmission occurs on a dedicated channel. We propose a further optimization applying multiple wireless network interface cards. This improvement in performance comes at the price of a slightly more complex hardware. Two different simulation models are implemented to investigate our approach. The first model investigates the MAC protocol and its improvements, while the second model analyzes the multihop performance in terms of delivery ratio and transmission delay. BY means of numerous simulations we present the performance of our MAC approach in comparison with two standard approaches in terms of bandwidth, packet delivery, and transmission delay. For our performance evaluation we apply the IEEE 802.11a technology, but we note that our approach can also be used for IEEE 802.11b.

Multi-TAP Controller Architecture for Digital System Chips

This paper describes an architecture for controlling multiple IEEE 1149.1 compliant TAP controllers on a single digital system chip. The key feature of this architecture is the compatibility with the IEEE 1149.1 standard, and existing debugger software. Results are presented, obtained from an experiment, in which the proposed architecture is mapped on an FPGA to control multiple existing designs with TAP controllers.

Sequential simulation applied to composite system reliability evaluation

The paper extends the application of sequential simulation to the analysis of composite generation and transmission systems. Most previous papers have described the application of sequential simulation to the generation system only. The paper summarises the basic characteristics of sequential simulation and describes theoretical and computational techniques that include models for the transmission system within the simulation process itself. It shows how the very nature of sequential simulation can be used with advantage to reduce significantly the computational effort that the simulation of composite systems originally involves. Algorithms based on the sensitivity of system busbars to overloads have been developed to simulate generation redispatch and load-shedding procedures. The feasibility of these reliability assessments for composite systems is demonstrated by applying the techniques to single and multiple IEEE reliability test systems.