超高速60GHz光載微波無線訊號系統

Abstract

The increasing demand for wireless video-based interactive and multimedia data services explains why 60-GHz wireless system is a promising candidate to provide multi-gigabit-per-second services. While attempting to generate and transmit 60-GHz signals in a wireless system cost effectively and increase the spectral efficiency to facilitate multi-gigabit-per-second services, this work presents four novel RoF systems based on optical frequency multiplication to reduce the bandwidth requirement of optical transmitters. In this thesis, the performances of RoF systems are investigated by theoretical analysis, VPI WDM-TransmissionMaker simulation, and experimental demonstration. Additionally, we employ RoF systems with OFDM modulation, single carrier modulation, adaptive bit-loading algorithm, I/Q imbalance compensation algorithm, and pre-coded method to successfully circumvent multiple system impairments resulting in significant system performance improvement. Optical I/Q up-conversion system with frequency quadrupling technique for 60-GHz RoF system are proposed. The advantage of the proposed transmitter is that no electrical mixer is needed to generate RF signal. Therefore, I/Q data of RF signals are processed at baseband at the transmitter, which is independent of the carrier frequency of the generated RF signal. Negligible power penalty following 25-km standard single-mode fiber transmission is observed, capable of significantly extending the service range to various applications within a building or campus. Electrical I/Q up-conversion RoF system which is a simple architecture for 60-GHz application are proposed. This system can achieve fiber transmission distances exceeding 3-km and 10-m wireless transmission distance without any chromatic dispersion compensation. Fiber links of 3km are sufficient for most short-range RoF applications such as in-building systems, where low system complexity is very critical. This work also demonstrates the 2×2 MIMO technique for capacity improvement of the proposed system. Both SISO and MIMO systems are achieved record data-rate within 7-GHz license-free band at 60 GHz and BER measurement results are below the FEC limit of 1x10−3. Hybrid access network which support both 60-GHz RoF and FTTx systems using a frequency multiplication technique are presented. One of architectures uses single-electrode MZM with frequency doubling technology. The other architecture uses dual parallel MZM with frequency quadrupling technology. Furthermore, wavelength reuse for uplink data transmission via a RSOA is also demonstrated. Two proposed hybrid access network systems exhibit no RF fading, no narrow-band optical filter is required at the remote node to separate the RF and BB signals, and vector signals are carried. Therefore, the proposed systems are compatible with the current PON system.

The increasing demand for wireless video-based interactive and multimedia data services explains why 60-GHz wireless system is a promising candidate to provide multi-gigabit-per-second services. While attempting to generate and transmit 60-GHz signals in a wireless system cost effectively and increase the spectral efficiency to facilitate multi-gigabit-per-second services, this work presents four novel RoF systems based on optical frequency multiplication to reduce the bandwidth requirement of optical transmitters. In this thesis, the performances of RoF systems are investigated by theoretical analysis, VPI WDM-TransmissionMaker simulation, and experimental demonstration. Additionally, we employ RoF systems with OFDM modulation, single carrier modulation, adaptive bit-loading algorithm, I/Q imbalance compensation algorithm, and pre-coded method to successfully circumvent multiple system impairments resulting in significant system performance improvement. Optical I/Q up-conversion system with frequency quadrupling technique for 60-GHz RoF system are proposed. The advantage of the proposed transmitter is that no electrical mixer is needed to generate RF signal. Therefore, I/Q data of RF signals are processed at baseband at the transmitter, which is independent of the carrier frequency of the generated RF signal. Negligible power penalty following 25-km standard single-mode fiber transmission is observed, capable of significantly extending the service range to various applications within a building or campus. Electrical I/Q up-conversion RoF system which is a simple architecture for 60-GHz application are proposed. This system can achieve fiber transmission distances exceeding 3-km and 10-m wireless transmission distance without any chromatic dispersion compensation. Fiber links of 3km are sufficient for most short-range RoF applications such as in-building systems, where low system complexity is very critical. This work also demonstrates the 2×2 MIMO technique for capacity improvement of the proposed system. Both SISO and MIMO systems are achieved record data-rate within 7-GHz license-free band at 60 GHz and BER measurement results are below the FEC limit of 1x10−3. Hybrid access network which support both 60-GHz RoF and FTTx systems using a frequency multiplication technique are presented. One of architectures uses single-electrode MZM with frequency doubling technology. The other architecture uses dual parallel MZM with frequency quadrupling technology. Furthermore, wavelength reuse for uplink data transmission via a RSOA is also demonstrated. Two proposed hybrid access network systems exhibit no RF fading, no narrow-band optical filter is required at the remote node to separate the RF and BB signals, and vector signals are carried. Therefore, the proposed systems are compatible with the current PON system.