Kamrok Lee

Aggregation Time Control Algorithm for Time constrained Data Delivery in Wireless Sensor Networks

This paper proposes and evaluates a new aggregation algorithm in wireless sensor networks with time constraint. In the proposed algorithm, each aggregation node controls its aggregation time in order to aggregate and transfer data from child nodes within a given deadline of the sink node. The objective of the algorithm is to deliver the time constrained data within time bound while reducing the energy consumption resulted from the number of transmissions. Based on the aggregation tree, the proposed algorithm considers the number of the child nodes to determine the aggregation time. The performance of the proposed algorithm is evaluated using both the miss ratio and the aggregation gain

A new home network protocol for controlling and monitoring home appliances - HNCP

In this paper, a new control network protocol, HNCP (home network control protocol), is proposed for controlling and monitoring home appliances. HNCP is a four-layered protocol and the standard message set is specified to guarantee interoperability between different home appliances and vendors. HNCP also specifies a detailed device-modem interface structure that guarantees the flexibility of modems.

Adaptive Channel State Routing for Home Network Systems Using Power Line Communications

In this paper, an adaptive channel state routing (ACSR) algorithm is proposed for home network systems based on power line communications (PLCs). The ACSR uses two metrics of channel state indicator (CSI) and distance to detect the state of a power line channel dynamically changed due to harsh power line environments with unstable and asymmetric paths. For decreasing network traffic, the ACSR provides each node with a probabilistic flooding method according to the number of neighboring nodes. For the performance evaluation of the A CSR, a test-bed that includes PLC modems with the ACSR is set up in a noisy environment. Experimental results show the feasibility of the ACSR algorithm.

Design and Implementation of Convergence sub-layer for a Heterogeneous Home Network

In this paper, a heterogeneous home network is designed and implemented using power line communications and IEEE 802.15.4. This paper presents the need of the heterogeneous home network in which IEEE 802.15.4 compensates for limitations of PLC based home networks. The convergence sub-layer (Cs-layer) is designed and implemented to enable a heterogeneous home network on the power line communication modem with IEEE 802.15.4 communication module. The main functions of Cs-layer are medium information management and medium selection. We built a test-bed and conducted experiments. Implementation and experimental results validate the feasibility of the Cs-layer to extend the PLC based home network to the heterogeneous home network.

An Energy-efficient Contention-based MAC Protocol for Wireless Ad Hoc Networks

In this paper, an energy-efficient contention-based MAC protocol (ECM) for wireless ad hoc networks is proposed. The ECM is the combined protocol of the power management scheme and the collision avoidance scheme of the IEEE 802.11 DCF to reduce the energy consumption of a node. The proposed ECM enhances power saving effects of the legacy IEEE 802.11 DCF, provides longer network lifetime, and delivers more packets than the power management scheme of the legacy IEEE 802.11 DCF. These results are shown throughout the simulation

Adaptive Channel State Routing Algorithm for Power line communication

In this paper, an adaptive channel state routing algorithm is proposed for power line communication. To consider the channel state which is dynamically changed due to unstable and asymmetric path, CSI (channel state indicator) and distance are used. To decrease network traffic, a probabilistic flooding method is used according to the number of neighboring nodes. In this paper, a test-bed is set up to evaluate the performance of the proposed routing algorithm. As performance measures, throughput, delay, path set-up time and average traffic are used. Experimental results show that the proposed routing algorithm has better performance than the previous shortest path routing algorithm without considering the power line channel state

Design and Implementation of Monitoring Software for Heterogeneous Control Network

XCP (extended control protocol) is an information oriented protocol which delivers information with high reliability according to the predefined rule. XCP network system can be implemented on top of several physical layer such as power line, IEEE 802.15.4 and so on. In this paper, a monitoring software that evaluates the reliability and performance of the XCP network is designed and implemented. This paper presents the structure and method of the packet monitoring in the network through several interfaces such as RS-232, ethernet. The feasibility of the implemented software is verified through the experimental evaluation.

Throughput and optimal ATIM window of IEEE 802.11 distributed coordination function in power saving mode

This paper analyzes the throughput and the optimal announcement traffic indication message (ATIM) window of the IEEE 802.11 Distributed Coordination Function (DCF) in the power saving mode. An analytical model based on Markov chain model is proposed to express the throughput and the optimal ATIM window in a mathematical form; it is validated by the simulation. The optimal ATIM window size is obtained to maximize the throughput and minimize the power consumption while solving the fairness problem.