Guest Editorial, Special Issue: Wireless Network Applications and Modeling
Yi‐Bing Lin · Wireless Communications and Mobile Computing · 2001
Wireless communications have made spectacular progress in recent years. In particular, the merge of various wireless communication systems and the data networks has become more critical so that users can enjoy all kinds of data services while owning mobility. For example, modern wireless networks can support Internet applications such as voice over IP (VoIP), web accessing and multimedia services. In this environment, a customer may use a wireless handheld device to access data services from the application server through the mobile network. To support the novel services mentioned above, service platforms and resource management mechanisms for existing mobile networks must be re-evaluated and enhanced. This special issue concentrates on wireless network applications and modeling. Five papers have been selected to address two major topics for supporting advanced mobile services. The first two papers investigate call admission control schemes that support users requesting various types of applications. The remaining four papers address how wireless and mobile network architectures can support Internet-based data applications. In the first paper, Bartolini and Chlamtac describe how to improve call admission control policies procedures by using handoff rate information in a wireless network. A general Markov Decision Process (MDP) model is used as an instrument to analytically compare the behavior of call admission control policies. If the handoff rate arriving to a cell is proportional to the occupancy level of the adjacent cells, then this approach allows a wide class of policies to explicitly incorporate the dependency between the handoff rate and the system state. Based on this model, some well known non-preemptive prioritization schemes are analyzed. In the second paper, Hou and Fang propose mobility-based call admission control schemes for wireless mobile networks. Multiple classes of mobile users (i.e. pedestrians and vehicular travelers) are considered in this study. The concept of influence curve is introduced to characterize the influence an ongoing call exerts on the adjacent cells for future resource usage. Based on this concept, the channel reservation can be dynamically adjusted. To overcome potential congestion, the authors also propose a new call bounding scheme to place a direct limitation on the number of new calls admitted to a cell. Four CAC schemes are proposed and analyzed by both analytical and simulation study. The results indicate that the new schemes are more effective in providing QoS than other previously known schemes. In the third paper, Pang et al. integrate the existing GSM service with Voice over IP (VoIP) features based on media gateway control protocol (MGCP). With the signaling protocol translation mechanism provided by the MGCP signaling gateway, the authors demonstrate how to interwork the MGCP elements with the home location register, visitor location register and mobile switching center in the GSM network. The message flows for GSM-IP registration, call origination, call delivery, call release and inter-system handoff procedures are implemented. The authors show the feasibility of integrating GSM with the MGCP-based VoIP network without modifying the GSM network. Performance enhancing proxies have drawn considerable interests from the network community as an effective approach to improve user experience in cellular networks. In the fourth paper, Jiang et al.. incorporate performance enhancing proxies into cellular IP networks. In this paper, the authors study the placement of proxy servers, especially the approach of incorporating proxies into cellular networks, which allows better, faster, and more secure proxy services. Various factors are discussed, including when to place proxies inside cellular networks, the information requirements of the proxies, the network requirements for supporting the proxy functions, and mobility management. Using GPRS as an example, the authors lay out a procedure for adding proxies into data transmission path in cellular networks. In the fifth paper, Misra et al.. provide application-centric analysis of IP-based mobility management techniques. The authors consider three applications: VoIP, mobile Web access and mobile server-based data transfers. Based on these applications, the authors evaluate the applicability of various IP-based mobility management mechanisms. The study indicates that diversity in the mobility-related requirements ensures that no single mobility solution is universally applicable, and the authors recommend a hierarchical mobility architecture based on Dynamic Mobility Agent (DMA). The proposed architecture efficiently manages intra-domain mobility and multiple application-based binding protocols for supporting inter-domain mobility. In the last paper, David Lee and William Lee share their experience in integrating global wireless systems with IP. They propose a standard-based all-IP wireless network architecture to support both data and voice. This architecture is wireless technology independent (can be applied for CDMA, GSM and TDMA) and can be deployed with minimum efforts with the combination of existing IETF and telecom standards. The mapping of PLMN and IP based addressing will be done through HLR to translate phone number based address (MIN) to IP based address. Vocoder issue can be resolved by using end to end solution or by providing an universal vocoder gateway in the inter-system network to minimize delay and improve performance. A trial hosted by Vodafone with Cisco, Hyundai and Telos was conducted in Reno, Nevada, USA. The trial reveals encouraging results on system integration time and performance. We would like to express our sincere thanks to all the authors who submitted papers, and the reviewers who provided revision reports for this special issue. Also, we would like to thank Mohsen Guizani, the Editor-in-Chief, and Mark Hammond, the Publishing Editor, for their assistance in editing this special issue. The work of Yi-Bing Lin was supported in part by MOE Program of Excellence Research under contract 89-E-FA04-4, CCL/ITRI, Ericsson, InterVideo, FarEastone, National Science Council under contract NSC 89-2213-E-009-203, the Lee and MTI Center for Networking Research, NCTU.