Gang Wu

A broadband wireless access system using stratospheric platforms

A Japanese national project for the development of stratospheric platforms (SPF) started in 1998 with the goal of constructing a new communications infrastructure. This paper describes this project, including the purpose, organizational structure, and current R and D activities. It focuses on the SPF-based broadband wireless access systems including the system scenario, system configuration, and services to be supported. Key technologies, such as the onboard multibeam antenna system and channel access schemes, are described.

An R-ISMA integrated voice/data wireless information system with different packet generation rates

To realize wireless multimedia communication networks, new MAC (medium access control) protocols are required and the MAC protocols for the integration of voice/data are now being studied. This paper proposes a MAC protocol called R-ISMA (reserved idle signal multiple access) for the integration of voice/data in wireless information networks. To meet the requirements of wireless multimedia communication, the R-ISMA protocol can handle both voice traffic and data traffic from various sources, i.e., from terminals with different generation rates. We describe this protocol, then evaluate the system performance by using the TFA (transient fluid approximation) analysis. The R-ISMA is shown to perform better than the I-ISMA (ISMA for integrated services) protocol.

A wireless ATM oriented MAC protocol for high-speed wireless LAN

Developments in new frequency bands for wireless communications make it possible to provide a broadband channel for new services. In order to implement integrated multimedia transmissions in a wireless environment without losing compatibility with the wired network, the concept of wireless ATM (WATM) is proposed. Compared with wired ATM, wireless access and mobility management are two major R&D topics for implementation of WATM. In this paper, we focus on the topic of wireless access and propose an integrated multimedia transmission protocol, which is based on the MAC protocol RS-ISMA (slotted idle signal multiple access with reservation), to support CBR, VBR, ABR and UBR transmissions as well as to provide immediate retransmissions. An RS-ISMA based prototype full-duplex high-speed wireless LAN in the 60 GHz band is under development.

Channel state dependent resource scheduling for wireless message transport

This paper discusses radio resource scheduling algorithms for wireless message transport over a burst-error channel. In high-speed wireless access networks, multipath fading or shadowing would cause burst packet errors which are no longer recovered by retransmissions or forward error corrections, thereby imposing a serious impact on the utilization of the wireless channel. Channel state dependent (CSD) resource scheduling algorithms are designed to utilize the channel status to improve the comprehensive performance. Computer simulations are carried out to evaluate the scheduling algorithms in terms of the average of allocation plus transfer delay, the average of throughput, the variance of throughput, and the utilization of resources. Our results show that by employing the CSD mechanism, significant improvement in the performance can be achieved.

An integrated transmission protocol for broadband mobile multimedia communication systems

This paper presents an integrated multimedia transmission protocol for future broadband mobile communication systems in the microwave band. The protocol is designed based on the physical layer devices using the CDM-(code division multiplexing) based parallel transmission scheme. Since the time-code-slicing technique is used, the proposed protocol is a joint CDMA (code division multiple access) and TDMA (time division multiple access). The protocol can allocate channel resources on demand of users with different information media and different QoS (quality of services) requirements and support wireless ATM system architecture. Since the protocol is based on the parallel transmissions, the SR-ARQ (selective repeat automatic repeat request) scheme is easily included in the protocol.

Performance Evaluation of Reserved Idle Signal Multiple Access with Collision Resolution

Medium access control (MAC) protocols have proposed since 1970’s for wireless communications networks. Idle Signal Multiple Access (ISMA) [1] and Reserved Idle Signal Multiple Access (R-ISMA) [2] were proposed as the examples of those MAC protocols. However, these protocols suffer from the system instability due to the random access mechanism. The instability problem can be found in most of MAC protocols using simple random access such as an ALOHA type with a fixed transmission probability.

Mobility management by basic access network in MIRAI architecture for heterogeneous wireless systems

A novel architecture for future integrated wireless network is proposed in MIRAI (Multimedia Integrated network by Radio Access Innovation) where a dedicated network takes care of the mobility functionalities of the participant wireless networks in the integration. The dedicated network, called Basic Access Network (BAN) is used primarily for wireless system discovery and paging whenever a call is initiated or a call arrives for the mobile user for any of the wireless interfaces of the users multi-module, multi-service terminal. In this paper, we analyze a model for using the BAN channel, and associated network to perform mobility functionalities of the integrated network environment in a seamless fashion.

A novel mobility management framework for future generation integrated wireless networks

The concept of using a separate network to carry signaling packets related to some basic mobility management functions in a heterogeneous wireless network environment has been proposed in MIRAI (multimedia integrated network by radio access innovation) architecture (see Wu, G. et al., IEEE Commun. Mag., p.126-34, 2002). In MIRAI architecture, a dedicated network takes care of the mobility functionalities of the participant wireless access networks. The dedicated network, called basic access network (BAN), is primarily used for paging whenever a call arrives for the mobile user for any of the wireless interfaces of the users multi-service terminal, and for wireless system discovery when the user wants to initiate a call/session. We present the operation of the BAN in concert with the rest of the IP-based network, to realize a common signaling framework for heterogeneous mobility.

Basic access network - the signaling-only network for power-efficient mobile multiservice terminals in MIRAI architecture

In MIRAI (Multimedia Integrated network by Radio Access Innovation) architecture, proposed by Wu, Havinga and Mizuno (see IEEE Commun. Mag., p.126-134, Feb. 2002), a dedicated network takes care of the mobility functionalities of the participant wireless access networks in an integrated wireless networks environment. This paper presents the dedicated network, called basic access network (BAN), which is primarily used for paging whenever a call arrives for the mobile user for any of the wireless interfaces of the users multiservice terminal, and for wireless system discovery when the user wants to initiate a call/session. The resultant improvement in network signaling and terminal power usage efficiency is discussed. The paper also outlines the implementation issues of the air interface of this unique network, with specific focus on the system capacity, coverage and power usage.

RS-ISMA with multimedia traffic in BRAIN

Developments in new frequency bands for wireless communications make it possible to provide a broadband channel for new services. The concept of BRAIN (broadband radio access integrated network in MM-wave band) comes about due to recent R&D activities in MM-wave communications. In order to implement integrated multimedia transmissions in a wireless environment without losing the compatibility with wired networks, the concept of wireless ATM (WATM) has been proposed. Compared with wired ATM, wireless access and mobility management are two major topics for implementation of WATM. In this paper, we focus on the topic of wireless access and propose an integrated multimedia transmission protocol, which is based on RS-ISMA (slotted idle signal multiple access with reservation), to support CBR, VBR, ABR and UBR service categories as well as to provide adaptive retransmissions for indoor systems of BRAIN.