Seongkwan Kim

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— Today's IEEE 802.11 WLANs (Wireless LANs) provide multiple transmission rates so that different rates can be exploited in an adaptive manner depending on the underlying channel condition in order to maximize the system performance. Many rate adaptation schemes have been proposed so far while most (if not all) of the commercial devices implement a simple(More)
Many rate adaptation algorithms have been proposed for IEEE 802.11 Wireless LAN devices and most of them operate in an open-loop manner, i.e., the transmitter adapts its transmission rate without using the feedback from the receiver. A key problem with such transmitter based rate adaptation schemes is that they do not consider the collision effect.(More)
WLAN technology has been shown a revolutionary development during the last decade. Recently popularized IEEE 802.11a/g-based products can support up to 54 Mbps PHY (Physical layer) rate and give much freedom to access the Internet wirelessly. However, the 802.11 MAC (Medium Access Control) protocol has relatively large overhead in order to robustly deal(More)
The performance of an IEEE 802.11 station heavily depends on the selection of an AP (Access Point) that the station is associated with to access the Internet. The conventional approach to the AP selection is based on the received signal strength called RSSI (Received Signal Strength Indication) from APs within the transmission range. This approach however,(More)
Today, IEEE 802.11 Wireless LAN (WLAN) has emerged as a prevailing technology for the broadband wireless networking. Along with many emerging applications and services over WLANs, the demands for faster and higher-capacity WLANs have been growing fast. In this paper, we propose a new medium access control (MAC) scheme for the next-generation high-speed(More)
While many existing rate adaptation schemes in IEEE 802.11 Wireless LANs result in severe throughput degradation since they do not consider the collision effect when selecting the transmission rate, CARA (Collision-Aware Rate Adaptation) [1] shows improved system performance thanks to its collision-awareness capability. In this paper, we propose two(More)
We present a transmission rate adaptation algorithm called AGILE (ACK-Guided Immediate Link rate Estimation) for IEEE 802.11 networks. The key idea of AGILE is that the transmitter adjusts the transmission rate by means of measuring the SNR (Signal-to-Noise Ratio) during any frame reception including the ACK (Acknowledgment) frame, and estimating the(More)
We provide a comparative analysis of various routing strategies that affect the end-to-end performance in wireless mesh networks. We first improve well-known link quality metrics and routing algorithms to enhance performance in wireless mesh environments. We then investigate the route optimality, i.e., whether the best end-to-end route with respect to a(More)
—We provide a comparative analysis of various routing strategies that affect the end-to-end performance in wireless mesh networks. We first improve well-known link quality metrics and routing algorithms to better operate in wireless mesh environments. We then investigate the route optimality and its impact on the network performance by comparing the(More)