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A b s t r I c t -Two con&ol techniques are proposed for assigning radio channels i n order to increase the spectrum eficiency.One is an autonomous channel assignment control for reusing radio channels at shorter distances according to the conditions of channels. The other is a control for assigning the channel of a nelghboring cell when there is no available channel in the closest cell. It is shown that these techniques are significant in mobile radio systems using sector cells and TDMA channels, and the spectrum eficiency is clarified by comparison of system capacity. I n t r o d u c t i o nThe demand for mobile communications is rapidly increasing.In order to cope with the demand, system operators need to achieve high capacity by increasing spectrum efficiency. Cell size reduction and scctor cells are often used to increase capacity.However, it is difficult to obtain the maximum potential only by reducing cell size or dividing an omni-cell into sectors. This i s because irregularities and variations of interference conditions increase in such systems, and more margins of conditions to assign a channel that decrease spectrum efficiency are nceded in order to deal with the variations.One method of solving this problem is channel assignment control. This selects a channel for a mobile and base station requiring radio communication in order to prevent interference and to increase spectrum efficiency. In conventional systems using usual cells, it is not necessary to apply advanced channel assignment techniques because channels are allocated with fixed reuse distances including sufficient margins. This paper proposes channel assignment control techniques which are unrestricted within a fixed channel allocation.The carrier to interference ratio (CIR) of both uplink (mobile-to-base) and downlink (base-to-mobile) requiring radio communication is detected and the transmission power control of mobile stations is used in order to increase the reliability of the CIR detection.If interference conditions could be estimated more accurately. channels reused at shorter distances could be selected. (This is called "flexible reuse"[l].)Moreover. it is shown that a technique to assign a neighboring cell's channel when there is no available channel in the closest cell of a mobile station is useful for increasing spectrum efficiency.Performance evaluations of the proposed techniques are carried out especially for a time division multiple access (TDMA) system using Sector cells. 2.

In this paper, we report a friendly supporting system for disabled people that is able to have comfortable feeling for both disabled and their assisting people using sound and image processing for being enhanced their Kansei. In short, this supporting system employs multi-modal interface adapter, which is able to operate easily with voice recognition, and a new combination of sound and image signals processing, which detect abnormal condition of disabled people. The multi-modal interface adapter consists of mouse emulator for operating all client equipments needed for daily life, and voice recognition for manipulating these apparatus. The sound processing judges unordinary state by detection of abnormal sounds from medical devices. At the same time, this device catches the client voice in surrounding noisy sounds. The image processing judges the abnormal states of disabled person and medical electric devices by images through the cameras. Some experiments have been performed and results show that each processing is effective key technology for a system configuration of supporting system. From these results, we find much possibility for a simple system, which is able to secure the privacy for disabled person and lighten the burdens of their helpers, and get comfortable feeling both disabled and assisting people of which assists and enhance their Kansei interface.

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