Wooguil Pak

Learn More
duty cycle of a wireless sensor node is a key factor that determines the life time of a wireless sensor network. In general, sensor medium access control protocols reduce the duty cycle to achieve longer lifetime. However, we found out that their performance improvements substantially decrease under extremely low duty cycles (<0.1%). Our proposed W-MAC(More)
To support various services in the current Internet, QoS routing was proposed. QoS routing finds a path to meet the requested QoS specification for a user, reserves network resource, thereby guaranteeing the QoS for the user. Many works have been done for QoS routing in an autonomous system (AS) to make it feasible in large networks. For a large network,(More)
—Policy lookup is a very essential function in packet forwarding and network security. As it is becoming a main cause of bottleneck in many network systems, this letter introduces a new policy lookup algorithm called FRFC (Fast table building for Recursive Flow Classification). Although it is based on RFC which shows the best policy lookup speed but the(More)
Keywords: Wireless sensor network Routing protocol Ultra low duty cycle Network lifetime Multi-hop wakeup time estimation a b s t r a c t Although various medium access control (MAC) and routing protocols have been designed for WSNs (wireless sensor networks) to extend the network lifetime, their performances are significantly aggravated under extremely low(More)
—In this paper, we propose a new centralized routing protocol named WRP that aims at maximizing the network lifetime. In WRP, the sink node is assumed to be with more capabilities and basically collects each node's estimated wakeup time. This enables the sink node to estimate the wakeup times of all sensor nodes even if some of them are multi-hops away from(More)
In wireless sensor networks, the routing control overhead could be large because multiple relays are involved in the routing operation. In order to mitigate this problem, a promising solution is to use tier-based anycast protocols. The main shortcoming of these protocols is that they can consume a much greater amount of energy as compared with other(More)