Jun Horikoshi

1.2 GHz band wave propagation measurements in concrete building for indoor radio communications

For the design of indoor radio communication or a portable radio telephone system, 1.2 GHz band radio wave propagation characteristics are investigated in a concrete building. Penetration loss through a window, local median variations, and cumulative distributions of received signal levels in a room, reflection coefficient or equivalent dielectric constant and transmission loss of a wall/floor are discussed.

Multipath distortion of differentially encoded GMSK with 2-b differential detection in bandlimited frequency-selective mobile radio channel

Error performance of Gaussian minimum-shift keying (GMSK) with 2-b differential detection in a frequency-selective mobile radio channel is analyzed. The two-wave model using two Rayleigh waves with constant group time-delay is adopted to describe a frequency-selective mobile radio channel. The Gaussian-type bandpass filter is introduced as a receiving filter to demonstrate the effects of band limitation at the receiver. A preferable receiving bandwidth in the frequency-selective mobile channel is also discussed. It is shown that the preferable receiving bandwidth is almost that obtained in an additive Gaussian noise channel since the magnitude of the interfering (or delayed) wave is relatively small. It is hardly affected by the maximum Doppler frequency and remains almost constant for the various parameters, e.g. average carrier-to-noise power ratio. >

Using microwave holography and microstrip antenna for 3D mouse investigation

A dynamic technique for establishing a three dimensional (3D) mouse is possible by combining holography with a microstrip antenna in order to enter 3D data into a computer. The idea depends on two techniques, the first generates a point source hologram from a dipole antenna. Secondly a receiving microstrip antenna will be attached to operators hand. A practical system for this purpose is constructed and performances are evaluated theoretically and tested experimentally. Scanning time is improved by replacing the antenna element with an array to achieve reasonable or real time results in editing 3D images. A simulation model is developed to create similar holograms. Experimental and simulation results give excellent agreement.

Multiple co-channel interference cancellation of GSM system assisted by MLSE and channel estimation

A co-channel interference cancellation scheme assisted by an adaptive channel estimation and equalization is developed for the effective use of radio frequency in the existing or on-going mobile communication system. This report clarifies the canceling ability of the proposed co-channel canceling algorithm for the GSM system under the multiple co-channel interfering environment. It is confirmed that the developed scheme works well also in the AWGN channel and the frequency flat fast-fading channel.

Modeling of arbitrary cross-sectional cylinder using N circular cylinders for the scattering calculations

Exact solution of the electromagnetic wave scattering by N dielectric cylinders is presented by using matrix formulation. To check this present method, two comparisons between exact solutions for a single circular conducting and dielectric cylinder and this model composed of N=25 circular cylinders are made. Numerical results of conducting and dielectric square cylinder has been also checked with well-known result (B.E.M). The scattering patterns and the near field distributions in space are presented for the concave, convex and dielectric circular cylinder with conducting reflector.

Error performance improvement of bandlimited QTFSK assisted by an efficient coded modulation and Viterbi sequence estimation

Spectral shaped quaternary-phase transition FSK (ss-QTFSK) is proposed and then its error performance improvement using an efficient block-coded modulation is confirmed. Error performance improvement in E/sub b//N/sub 0/ reaches up to 3 dB to achieve a BER of 10/sup -3/ in the case coding efficiency being 0.9 (the additive Gaussian channel and a differential detection/Viterbi sequence estimation are employed for the above analyses).<<ETX>>

Improvement of error performance of digital modulation in the mobile radios using a novel multi-level FSK-QTFSK (quaternary-phase transition FSK)

A modulation scheme, named QTFSK (quaternary-phase transition FSK) is proposed for digital mobile radio applications, especially when severe power saving is required. As QTFSK is essentially a continuous phase FSK modulation scheme, it is preferable for satellite-mobile systems. It is clarified theoretically and experimentally that the error performance is almost the same as that of QPSK in the Rayleigh fading channel. The main lobe of the signal spectrum is a little narrower than QPSK.

An efficient technique for constructing a microwave hologram with the use of a microstrip array antenna and the retrieval of the digital form

We propose a dynamic technique for a microwave holography system. We use a microstrip patch antenna in constructing the hologram and a new correlation method to reconstruct its digital form. The new reconstruction idea is based on the correlation between the hologram of point source and the hologram of object. Experimental results of our microwave holography system agree well with simulations, verifying our new holographic technique.

MLSE multiple co-channel interference canceling with channel estimation for future mobile radios

The basic performance of a multiple co-channel interference canceler assisted by channel estimation and diversity is clarified. It is assumed that the receiver knows the unique-word or identification code of each interfering signal. A simplified Viterbi algorithm for multiple co-channel interference cancellation is proposed and the error performance is clarified.

Turbo codes with RLS-MLSE channel estimation in the co-channel interference environment

Turbo codes is known as a powerful error correcting code. Since the turbo decoder reflects not only the hard decision but also the reliability of the received signals, a great coding gain can be obtained. Also maximum likelihood sequence estimation (MLSE) with adaptive interference cancellation (AIC) is effective to reduce the influence of fading and co-channel interference. Therefore, we propose a system that combines turbo codes and RLS-MLSE. The proposed system estimates the desired signal and interference signal separately at the MLSE part. The output of the MLSE is estimated as the desired signal on the survived path of the Viterbi estimator, which is a soft value. Then the soft value that does not contain interference component is input to the turbo decoder. The simulation result shows that the proposed system has a superior performance to the system only with MLSE.