||Due to development of modern Internet, the applications of smart devices also have a thriving development, implying a great demand for broadband data transmission. Therefore, how to process signals in a simple, fast and cost-effective manner is the focus of modern communications.|
High-frequency signals in either the traditional coaxial cable or the atmosphere are subject to considerable transmission loss, resulting in limited transmission capacity and distance. Therefore, the application of Orthogonal Frequency Division Multiplexing (OFDM) technology to Passive Optical Network (PON) is considered as one of the most promising candidate to provide enough bandwidth and solve the problem of transmission loss. However, the standard OFDM-PON system suffers from the disadvantage of being cost-prohibitive because it needs to receive redundant signals. Thus, a standard OFDM-PON system needs an expensive high-speed converter to demodulate signals. In previous works, Delay Division (DDM) Multiplexing OFDM-PON technology has been proposed to overcome the above shortcomings. However, the DDM OFDM-PON technology can only assign the same data capacity to all virtual groups, limiting the flexibility and adaptability to the current network architectures. Besides, there is no available technology to improve the performance of this system.
This thesis proposes a new method that can accommodate virtual groups with different sampling rates and capacities, thereby increasing the flexibility. In addition, this work proposes novel techniques to improve the performance of the DDM system, including pre-emphasis, bit-loading, and channel response estimation. The channel estimation technique is particularly central in an APD-based DDM system.