In the operation of hierarchical mobile IPv6 (HMIP) (H. Soliman, et al., 2003), a mobile node (MN) is supposed to send binding updates (BUs) to the home agent (HA) and a mobility anchor point (MAP); therefore, a MAP discovery protocol is needed to facilitate MN discovery of MAPs. Two protocols were previously proposed in (H. Soliman, et al., 2003) for MAP discovery, however, in both protocols, all access routers (ARs) must issue router advertisements (RAs) with MAP information option fields in order for the MNs to receive them. In such MAP discovery protocols, ARs must be aware of HMIP operation for the advertising of MAP information. In this paper, we introduce a new MAP discovery protocol that is transparent to ARs. Such transparency would bring about wider applicability for HMIP than previously achieved, which is important from industrial and commercial viewpoints. In addition, we confirm that the proposed protocol meets the requirements, and we evaluate its performance by computer simulation.

Mobility support for mobile networks will be more important as the mobile Internet becomes increasingly popular. To support mobile networks, the concept of prefix scope binding (PSB) is being discussed in IETF; however, by only applying this concept to Mobile IPv6 (MIP), the problem of packet loss still remains. In this paper, we apply the PSB concept to our proposed protocol, the hierarchical Mobile IPv6 extension with buffering function (HMIP-B), in which mobility anchor points buffer packets destined to the mobile hosts during handoff. We compare MIP and HMIP-B based on the handoff performance related to mobile networks by computer simulation. The simulation results indicate that our proposal improves the handoff performance in both TCP and UDP communications.

With the rapidly increasing demand for high-speed mobile multimedia and the need to support diversified requirements of users by packet communication systems, wireless quality of service (QoS) resource management becomes more and more indispensable, especially for the IMT-2000 system and beyond. In previous researches, QoS controls carried out independently at base stations have been proposed. However, in a CDMA packet communication system where channel capacity varies dynamically due to the variant interference level, QoS satisfaction and the system capacity may not be optimised while considering the entire system. In this paper, the essential factors of wireless QoS control are denoted and a wireless QoS resource management for packet mobile communications with base station power resource cooperation control is proposed. Computer simulation indicates that the QoS satisfaction rate and the system capacity are improved remarkably by the proposed scheme with base station power resource cooperation control. The improvement becomes ever larger when real-time and nonreal-time traffic distributed in an unbalanced manner, which further elucidates the effectiveness of the proposed resource cooperative control scheme.

With the rapidly increasing demand for providing highspeed mobile multimedia and supporting diversified requirements of users, wireless quality of service (QoS) resource management becomes more and more indispensable, especially for the upcoming IMT-2000 system and beyond. In this paper, a wireless QoS architecture and two QoS resource allocation algorithms for CDMA cellular systems are proposed to meet these requirements. Based on the proposed QoS architecture, an adaptive QoS resource management is proposed to assign radio resource corresponding to its availability and the users' maximum and minimum QoS requirements. A service-rank-based QoS resource management is further proposed to satisfy more high-rank users as much as possible while maintaining the minimum requirement of low-rank users. Computer simulations indicate that the proposed QoS resource management algorithms exhibit superior performance with respect to dropping probability, rate of satisfied users and necessary transmission time, which indicate higher satisfaction rate of users and better performance.

This paper presents a system architecture for mobile communications systems beyond IMT-2000 (4G system). Considering the growth of data communications through mobile networks, the 4G system should offer higher bit rate channels and accommodate a significantly larger amount of traffic. To meet these requirements, the 4G system may use higher frequency bands. This paper first considers objectives of the 4G system and it proposes a system architecture that meets the objectives. The architecture proposed in this paper comprises core networks that will accommodate multiple types of radio access networks (RAN). The 4G RAN is constructed by distributed controlled base stations that are connected to each other by a multi-hop wireless network.

Mobile IPv6 supports packet routing for hosts moving on the Internet, but lacks support for networks moving on the Internet. For example, a network comprising a set of hosts and routers in a train can be a mobile network. While the mobile network is moving, a router in the network changes its point of connection to the Internet. This paper proposes an architecture and Mobile IPv6 extensions that support packet routing for mobile networks. The proposed scheme enables any host on a mobile network to communicate with any host connected to the Internet.

Since code-division multiple-access (CDMA) capacity is interference limited, call admission control (CAC) must guarantee both a grade of service (GoS), i.e., the blocking rate, and a quality of service (QoS), i.e., the loss probability of communication quality. This paper describes the development of a new capacity design method based on these two concepts. Theoretical expressions for GoS and QoS as functions of traffic intensity and CAC thresholds are first derived from the traffic theory viewpoint, and then a design method using these expressions is presented. At that time, two strategies for CAC are assumed. One is based on the number of users, and the other is based on the interference level. Computer simulation results are presented that strongly support the proposed design method. Furthermore, numerical examples and a performance comparison of the two strategies considering various propagation parameters, nonuniform traffic distributions, and various transmission rates are shown.