A prototype ultra-wideband channel sounder with time delay resolution of 0.5 ns has been developed. The sounder uses the spread spectrum technique based on the classical sliding correlator, however it can measure a power delay profile up to a time delay of 16 /spl mu/s with 5 kchip/s in real time. And also, it has more than 35 dB amplitude dynamic range with a very simple hardware structure.

Is this paper, we propose a W-CDMA reception scheme using code combing RAKE with error-and-erasure correction Viterbi decoding. All techniques require only binary operations. The objective is to achieve relatively high transmission performance with very low receiver complexity and power consumption. The performance study of the proposed scheme is carried out taking into account the interference from other users, AWGN and random FM noise. Good performance is confirmed.

Amplitude notches in the transmission band have a large effect on high-speed digital mobile communication. This paper presents frequency domain analysis and measurements of multipath propagation for high-speed digital mobile radio communications in 400 MHz band. Multipath propagation characteristics of high-speed digital transmission are expressed in terms of in-band notch occurrence (IBNO), in-band notch 3dB-bandwidth probability (IBNW), and in-band group delay characteristics (IBGD). These characteristics are analyzed by Fourier transformation of delay profiles of five test routes in microcellular environments of 400 MHz around Kyoto University, Japan. IBNO and IBNW are compared with the infinite multipath wave model. Non-minimum phase shifts have been found to occur under condition of receiving delayed waves with higher level than proceeding waves. Non-minimum phase shift occurrence per notch (NMPS) is also calculated by treating IBGD. Delay spread and notch occurrence correlation are analyzed for the five test routes.>

A wide band channel sounder suitable for indoor radio propagation measurement is discussed. The most common sliding correlation technique is shown to be suitable for the very fine delay resolution. Based on this technique, a prototype sounder has been developed. It has a delay resolution with 5 ns and more than 35 dB amplitude dynamic range by using a 7-stage maximum length sequence.>

The so-called irreducible error due to frequency-selective fading is known to have a serious effect on mobile radio communication systems. Thus, the analysis of such errors is a prerequisite for making high-speed digital signal transmission over a fading channel feasible. The authors attempted to elucidate the physical mechanisms causing such errors using laboratory measurements of microscopic bit error rate. The results clarified some sources of burst errors in a multipath fading channel. In particular, large and rapid timing fluctuations of eye pattern due to severe delay distortion of the multipath channel was found to be the most dominant source of error.>

This paper describes a new modulation technique called DSK (double phase-shift keying) which shows an interesting antimultipath feature over mobile frequency-selective fading environments. The effect of this technique is shown for various multipath channels by detection waveform and theoretical bit error rate (BER) analyses. A result obtained from a laboratory test is also presented. In the latter part of the paper, a generalized form of DSK is described and extensive investigations are made so as to clarify the anti-multipath effect of DSK in view of the diversity concept and to further explore the possibility of a narrowband scheme. A major result shows that this technique can give a kind of diversity effect which is implicit in the arrival of signals via multiple paths with different delays.