| Summary: | 碩士 === 國立交通大學 === 光電系統研究所 === 106 === Because of the popularity of handheld mobile devices and the rapid development of wireless communication technology, the mobile device can support multimedia applications, and wireless communication can provide mobility and broad coverage. Therefore, users using Internet services are not any longer for regional restrictions, and it brings great convenience to people. However, with the development of high-definition and high-quality audio, video, interactive multimedia applications, and the demand of cloud storage, the global mobile network data is increasing quickly. In order to meet the explosive demand of the data rate from multimedia and cloud storage service, wireless communication systems must be developed to higher radio frequency to provide more signal bandwidth and higher data rate.
In recent year, there is more and more attention and interest to Teraherz wireless communication, which has ultra-broadband to connect base station for backhauling in the future. Several transmission experiments have been reported at 120 GHz, 140 GHz, 200 GHz, 220-240 GHz, 250 GHz, 300-400 GHz, and 625 GHz. But, due to the high cost of manufacturing Terahertz RF ICs in Terahertz communication, there needs other technology to meet the demand of higher frequency and cost-effective system for commercial value.
Therefore, in order to meet the simultaneously requirements of the huge bandwidths, high data rates, and flexible access in the next generation access network, it is desirable to deliver wired and wireless services to the end-user in an efficient, reliable, and affordable cost per unit of bandwidth.
In this paper, we will propose a novel architecture based on IMDD system. Then, using optical coherent detection system is for RAUs to generate RF signal. The optical coherrent detection can generate any high frequency without restriction. The power detector can down-convert any high frequency signal to baseband and overcome the traditional coherent phase noise without any compensation. Therefore, the system is no need any eletronic mixer and local oscillator to up-sample or down-sample for singal, but the nonlinearity will grow up. Using IMDD system to self-eliminated the nonlinearity. This way is high cost-effective, integrated wired and wireless access, and keep one of the potential candidates for transmitter in Terehertz wireless communiction.
However, there is low power efficiency and low spectral efficiency for wireless channel by using intensity modulation. In order to improve power efficiency, we would use EML bias voltage to suppress laser carrier power which might cause EML nonlinearity to grow up. So, we would use Volterra nonlinear compensation to mitigate the nonlinearity. The other issue is using two-segment EAM to generate SSB signal to improve wireless spectral efficiency. There also needs to discuss the nonlinearity for the case by using Volterra nonlinear compensation. Hence, the proposed system provides a simple and cost-effective solution to future broadband hybrid access networks.
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