Yoshihiro Hase

A novel broadband all-wireless access network using stratospheric platforms

This paper proposes a novel broadband access network using a number of stratospheric platforms. This is a new wireless infrastructure, and consists of wireless access links between the platform and terminals in the Ka-band and a mesh-like network using optical inter-platform links. One platform covers a 40 km/spl times/40 km area with 64 beams of an onboard multi-beam antenna. Thus, the cell size is almost as same as that of current cellular systems. This network can provide 25 Mbps to more than 156 Mbps access links and a flexible wireless ATM network to subscribers.

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.

Performance analysis of interference between UWB and SS signals

Much attention has been paid to a new form of spread spectrum technique called ultra wideband (UWB) impulse radio system for future high speed wireless communication services. In this paper, we derive some expressions which quantify UWB interference to SS signal and vice-versa. This theoretical analysis is then compared with computer simulations.

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.

Land mobile communication experiments with ETS-V satellite

A geostationary satellite named ETS-V is scheduled to be launched in the summer of 1987. With this satellite, experiments on mobile satellite services will be performed to study basic technology for future integrated mobile satellite systems through the Experimental Mobile Satellite System (EMSS) by L-band frequencies (1.6/1.5GHz). Several kinds of land mobile earth stations are provided for the experiments. G/T and EIRP of these earth stations range from -20dBK to -18dBK and from 6dBW to 20dBW respectively. Automobile earth stations with voice or data terminal employ ACSSB and 2.4kbps BPSK-SSMA as the modulation technique. A hand-held earth station is prepared as bi-directional low speed message communication terminal which employ 100bps Digital FM (CPFSK). Field tests will be carried out from the autumn of 1987. Experimental results of the EMSS will contribute to future operational mobile satellite systems.

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.

R&D of Mobile Communications Systems Using Stratospheric Platforms

A new national R&D project on novel communication systems using a number of high altitude large airships(stratospheric platform). The pla t form will be used as base station and switching center for various types of communication systems. The goal of the national project is to develop key technology for stratospheric platform system in several years and to demonstrate it using airship in stratosphere . [1] This paper describes various ap plications and network system design of IMT2000 mobile communications system using stratospheric plat form (SPF) and plan of mission flight tests 2002. INTRODUCTION Research on the use of stratospheric platforms (SPFs) for wireless communication is being con ducted in Japan jointly by the Ministry of Education , Culture, Sports, Science and Technology (MEXT) and the Ministry of Public Management, Home Affairs, Posts and Telecommunications (MPMHAPT). An SPF is an unmanned airship kept at a stratospheric altitude and used for radio communications, broadcasting, earth observation, and monitoring. [1] The requirements for an SPF are station-keeping efficiency, long period undisturbed operation , [mission payload and power supply capability], mission recovery (reuse), and stratospheric environment-friendly. Therefore an unmanned large airship type is the most promising candidate . The Telecommunications Advancement Organization of Japan ( TAO) [2] and The Communication * Researcher, Yokosuka Stratospheric Platform Research Center, TAO of Japan, Yokosuka, Japan † General Manager, Yokosuka Stratospheric Platform Research Center, TAO of Japan, Yokosuka, Japan ‡ Head, Research Planning Office, Communications Research Laboratory, Japan § Group Leader, Senior Researcher, Communications Research Laboratory, Yokosuka, Japan ¶ Executive Director Business Operation Division NEC TOSHIBA Space Systems, Ltd . Research Laboratory (CRL) are research ing and developing a radio communications system and a broadcast ing system that use SPFs. In this article we will describe characteristics and various applications and network system designs for mobile communications (IMT2000 system) that use SPFs. We also describe the flight tests planned for 2002. Experiments and demonstrations will be conducted using a helicopter flying 3 km high. Finally, we describe a stratospheric communication experiment planned for 2002 that will use a so lar-powered stratospheric plane, the “Pathfinder Plus”, and be conducted in cooperation with NASA. R&D SCHEDULE & PROGRESS (1998-2004) (1) 1998: Conceptual design of mobile communications systems using SPFs (2) 1999: Basic design of mobile communications systems using experimental airship (3) 2000: Design and manufacture of on -board mobile communications system for preliminary experiment (4) 2001: Design and manufacture of IMT2000 base station system for preliminary exp eriment (5) 2002: 1) Preliminary experiment using helicopter 2) Stratospheric communication experiment us ing solar-powered stratospheric plane deve loped by NASA (6) 2003: Design and manufacture of IMT2000 test system for low-altitude position-controlled airship test (7) 2004: Low-altitude position-controlled airship test The R&D schedule for the mobile communic ation system using SPFs is shown in t able 1. [2] 20th AIAA International Communication Satellite Systems Conference and Exhibit 12-15 May 2002, Montreal, Quebec, Canada AIAA 2002-2002 Copyright

Dynamic resource assignment for stratospheric platform communication system with multibeam antenna

A novel radio resource management approach composed of the space division multiple access (SDMA) strategy and the dynamic resource assignment for the stratospheric platform (SPF) communication system is proposed. Since the whole channel resource is shared with each beam of the digital beamforming (DBF) multibeam onboard antenna, it realizes our objective by making good use of the spectrum resource to meet the increasing demand of mobile communications and broadband fixed wireless access (FWA) services within the limited spectrum. Computer simulation result illustrate that the communication capacity of an SPF communication system increases significantly.

156 Mbps ultrahigh-speed wireless LAN prototype in the 38 GHz band

This paper presents a 156 Mbps ultrahigh-speed wireless LAN in the 38 GHz millimeter (mm)-wave band. The system is the third prototype developed at the Communications Research Laboratory since 1998. Compared with the previous prototypes, the system has the following characteristics: higher speed (156 Mbps), smaller size (volume of radio transceiver < 1000 cc), larger service area (two overlapping basic service sets), and longer transmission distance (the protocol can support a distance of more than two hundred meters). The development is focused on the physical layer and data link control layer, and thus a GMSK-based mm-wave transceiver and an enhanced RS-ISMA (reservation-based slotted idle signal multiple access) are the key development points. This paper covers the prototype systems design, configuration, and implementation.