CATV broadband access system based on OFDM technology

Abstract

An OFDM-based broadband access system of a cable television network is provided, which comprises a CATV photoreceiver, a television, an OFDM-based coaxial cable exchanger, a data mixer, a data jumper, a CATV distribution network, and an OFDM-based data terminal. The OFDM-based coaxial cable exchanger comprises an Ethernet optoelectronic converter, an OFDM modulation / modulation module, a power supply module, an Ethernet interface unit, an Ethernet reception / transmission unit, a CPU, a radio-frequency reception / transmission unit, a test signal source, and a radio-frequency interface unit. The invention has the advantages that the common cable transmission of television signal and data signal is realized; the OFDM modulation technique helps to enhance the system resistance to noise and ensure the system operation more stable and reliable; and the value of the existing cable television network is increased with low investment.

Description

technical field [0001] The invention relates to the field of broadband networks, in particular to an OFDM technology-based cable TV network broadband access system. Background technique [0002] OFDM (Orthogonal Frequency Division Multiplexing) technology is a kind of MCM (Multi-Carrier Modulation, multi-carrier modulation). Its main idea is to divide the channel into several orthogonal sub-channels and convert high-speed data signals into parallel low-speed sub-channels. A data stream, modulated for transmission on each sub-channel. [0003] Cable television system (CATV) refers to a system that provides sound, image, and data signals to end users through wired transmission media such as optical cables or coaxial cables. With the steady growth of cable TV users in recent years, the steady translation of digital TV, and the rapid development of the Internet, the proportion of optical cables in cable TV systems is increasing; Attempts were made to provide subscribers with b...

AI Technical Summary

Problems solved by technology

The above systems have the following problems that are difficult to solve: the upstream funnel noise problem has a great impact on data transmission, and the CMTS itself covers a relatively large area, and the noise gathered in the front-end equipment room also increases accordingly. When the noise level is greater than the data level The entire system will be paralyzed; the CMTS technical solution belongs to the way of sharing bandwidth, and the speed is relatively fast when the number of users is small, but as the number of users increases, the bandwidth will also decrease accordingly, which is not conducive to long-term development; The scope of transformation of the cable TV system is very large, and the requirements for the network are very high. All amplifiers must be replaced with bidirectional amplifiers, and equipment such as reverse optical transmitters, reverse optical receivers, and bidirectional filters must be added.

Images