Outage probability evaluation for a new category of wireless access systems is discussed. Wireless access systems dealt with in this paper are links which connect a portable terminal to a base station through a line-of-sight path. It is also assumed that the terminal equipment is operated in a still atate during actual communications. This mobility restriction enables the wireless access to have a capacity as high as the Mbit-order with high quality performance. Multipath fading observed in such a system may have more moderate variations than Rayleigh distribution. This paper tentatively designates the above wireless access as relocatable systems, and attempts to analyze their error performance, approximating the fading characteristics with Gamma-distribution. Also dynamic relations between bit error rate (BER) and signal-to-noise ratio are calculated under Gamma-distribution fading. Based on the analyses prediction methods for outage probability of typical QPSK systems are given, and thus it is established to design the performance aspect of relocatable systems with different features from both fixed and mobile systems.

Error performance as well as ATM cell transfer characteristics in a new category of wireless access systems is discussed. Relocatable wireless access with neutral feature between the fixed and mobile systems can convey Mbit/s-order capacity with fairly high quality under line-of-sight propagation. It is an important question for such wireless access systems whether they are able to form a part of wired networks satisfying performance objectives specified in ITU-T Recommendations. This paper analyzes the characteristics of relocatable systems under Gamma-distribution fading environments, and clarifies quantitative relations between Bit Error Rate (BER), Severely Errored Second (SES), Errored Second (ES) and Cell Loss Ratio (CLR) in a calculation model employing QPSK and typical HEC (Header Error Control). Thus it is demonstrated for the first time that in most cases the dominant parameter is the SES objective. Also it will be possible for a relocatable system with appropriate fade margin to meet the ITU-T performance specifications.

This paper outlines technical trend of multimedia mobile and broadband wireless access systems utilizing comprehensive concept and new categorization of wireless access. It is pointed out that mobile communications have much potential market in future high-speed data or IP (Internet Protocol)-based traffic. Categorization of three kinds of wireless access is presented based on the definition adopted by the Radiocommunication Sector in ITU. IMT (International Mobile Telecommunications)-2000 and broadband wireless LANs (Local Area Networks) each representing mobile and nomadic wireless access will bring about a turning point to a new era that wireless communications become dominant media in access networks. With this perspective technical subjects, spectrum consideration and deployment scenario for these systems are discussed.

This paper describes an experimental investigation on the phase constant and the cutoff wavelength of a cocoon-section corrugated waveguide (CCWG) with a cocoon-cross-section configuration and a sinusoidal-wave helical corrugation along the longitudinal axis at guide-walls. The CCWG is widely used for antenna feeder waveguides of the 4, 5, 6 and 7 GHz-band microwave communication systems. The purpose of this investigation is to get a useful means for an easy design of the corrugated waveguide. We have measured resonance frequencies of cavities made of 4, 6 and 7 GHz-band CCWGs at frequencies between 3 and 8 GHz by means of a resonant cavity method. As an example of results, the measured phase constant of the 4 GHz-band CCWG is a few percents larger at the frequency range 3.64.2 GHz than the calculated one of a cocoon-section smooth waveguide (CSWG) with a tube diameter equivalent to the center diameter of corrugated guide-walls. And the measured cutoff wavelength is nearly equal to the calculated value of the CSWG. As a result of this investigation, the experimental equation showing a dispersive property of the phase constant of the CCWG is led assuming that the corrugation size is small as compared with the major diameter.