Tsutomu Niiho

Multi-channel wireless LAN distributed antenna system based on radio-over-fiber techniques

We introduce the multi-channel WLAN system based on RoF techniques that realize efficient and flexible network operations. Single-channel optical transmission characteristics of an IEEE802.11a or 11b signal are clarified, and multi-channel transmission performances are discussed.

Transmission performance of multichannel wireless LAN system based on radio-over-fiber techniques

We clarify the transmission performance of our proposed multichannel wireless local area network (WLAN) system based on radio-over-fiber techniques. We developed a practical and effective method for the analysis of multichannel performances from the measurement of single-channel performances by incorporating the spectral distribution of a modulation signal into a calculation of the composite triple beats. Furthermore, using our developed method, we can clarify the maximum capacity of the multichannel WLAN system and its system parameters with a focus on the performance of the orthogonal frequency division multiplexing with 64-quadrature amplitude modulation channel. For example, the cell diameter for realizing the bidirectional transmission of seven-channel WLAN signals becomes 10 m.

Radio-over-fiber transmission performance of OFDM signal for dual-band wireless LAN systems

We propose the dual-band wireless LAN system based on radio-over-fiber technique. A demonstration of optical transmission of 5-GHz OFDM signal specified in IEEE802.11a and a feasibility of 2.4/5-GHz dual-band transmission will be reported.

Multiband wireless LAN distributed antenna system using radio-over-fiber

In this paper, we propose a novel radio-over-fiber multiband wireless LAN distributed antenna system and also describe a noise canceling technique applied to counteract the problem of received RF signal degradation caused by the noise generated by the O/E in a remote antenna unit.

Proposal of RoF transmission system using 850 nm VCSEL and 1.3 /spl mu/m SMF with low-frequency superposition technique

We propose a novel RoF transmission system with a combination of 850 nm VCSEL and 1.3 /spl mu/m SMF. Using the low-frequency superposition technique, we demonstrate the RoF transmission of OFDM-64QAM signal with significant reduction of modal noise and distortions.

Influence of clock structure on EMI level and audio clock jitter during high-speed serial transmission

In this study, we investigated the influence of the separate-clock structure and embedded-clock structure on the characteristics of electromagnetic interference (EMI) and audio clock jitter during high-speed serial transmission. We found that the EMI peak spectrum of a separate clock can be reduced by 11 dB if its frequency is decreased. The peak spectrum of transmission when using a separate clock is much lower than that of transmission when using an embedded clock, and results in less audio-clock jitter than transmission using an embedded clock.

Effects of interference on multi-channel wireless LAN distributed antenna system based on radio-over-fiber techniques

The effects of several kinds of interference on multi-channel wireless LAN optical transmission systems are appreciated. It is shown that amplitude distributions of these interferences have large impact on the PER and EVM characteristics.