We present a numerical analysis of the optimal number of groups for minimizing the average paging delay. In the analysis, we consider uniform distributions for location probability conditions and apply the M/D/1 queueing model to paging message queues of cells. We also compute the lower bounds of group numbers and investigate the minimum transmission capacity under average paging delay constraints.

Ad-hoc networks do not need any preexisting network infrastructure and have been developed as temporal networks in various fields. An infostation is a system to relay information that is not delay-sensitive. In this paper, we propose an early disaster warning system built on infostations and an adhoc network composed of sensors attached to moving animals. We analyze the performance of the proposed system by simulation. The analysis results show that the proposed system will be very useful in the early detection of big forest fires which occur frequently in Korea mountain areas.

In this letter, we propose an enhanced time-based registration method and analyze the performance numerically. In the analysis, we assume Poisson call arrival distribution and exponential cell resident time. The performance of the enhanced time-based registration method is compared with the performance of the original time-based registration method. In the comparisons, we see that in a certain range of parameters, the enhanced time-based registration method has better performance.

In the virtual home environment (VHE), which was proposed to offer global roaming and personal service environment portability, user's profiles and service logics are conveyed from home network to visited network to provide services at the visited network. Because user's profiles and service logics may contain confidential information, some procedures for mutual authentication among entities for offering confidence are needed. For these issues, we propose and analyze 3 party mutual authentication protocols adaptable to the VHE in 3G.

Due to the proliferation of mobile devices connected to the Internet, implementing a secure and practical Mobile IP has become an important goal. A mobile IP can not work properly without authentication between the mobile node (MN), the home agent (HA) and the foreign agent (FA). In this paper, we propose a practical Mobile IP authentication protocol that uses public key cryptography only during the initial authentication. The proposed scheme is compatible with the conventional Mobile IP protocol and provides scalability against the number of MN's. We also show that the proposed protocol offers secure operation.

Mobile Multi-hop Relay (MMR) technology is usually used to increase the transmission rate or to extend communication coverage. In this work, we show that MMR technology can also be used to raise the network capacity. Because Relay Stations (RS) are connected to the Base Station (BS) wirelessly and controlled by the BS, an MMR network can easily be deployed when necessary. High capacity MMR networks thus provide a good candidate solution for coping with temporary traffic surges. For the capacity enhancement of the MMR network, we suggest a novel scheme to parallelize cell transmissions while controlling the interference between transmissions. Using a numerical example for a typical network that is conformant to the IEEE 802.16j, we find that the network capacity increases by 88 percent.

A packet diversity scheme is introduced to increase uplink channel efficiency in a wireless network where forward error correction is used. The packet diversity allows neighbor base stations to receive uplink packets from a mobile terminal in order to increase the efficiency of the uplink channel. By allowing multiple base stations to receive the same packets, we can improve the error correction capability in an uplink channel. By incorporating the packet diversity we can reduce the parity overhead of each packet for a given tolerable loss probability, which improves the link efficiency.

In this letter, we propose a hybrid authentication algorithm to alleviate the latent security problems of mobile multi-hop networks. The proposed scheme uses centralized authentication when a node first joins the network, and uses distributed authentication for the hop-by-hop authentication among multi-hop nodes. We also analyze performance of the proposed scheme.