A Novel Approach to Parallel Channel Transmission in Digital Terrestrial and Handheld Television

摘要

Over the past forty years, communication systems have been steadily changing. Narrowband transmission systems have had a dominant place in communications due to the low system complexity. Of course, narrowband communications, as any communications system, is limited by the Shannon Rate which is a function of channel noise. In the late 1960''s, a scientist at Bell laboratories, Robert Chang, developed a system that could approach the Shannon Rate in a way that narrowband systems could not (due to the high order filters required to prevent inter-channel interference. The system developed by Chang was entitled Orthogonal Frequency Division Multiplex (OFDM) and over the past 15 years, has become increasingly dominant in the communications market for such applications as wireless networking, digital terrestrial television and more recently, digital hand-held television. There are a number of problems with OFDM, however, that although many applications do not necessarily see them as such, need to be looked at in order to maximize the potential for wireless communications. This paper will explain some of these problems and give preliminary investigation details on a new proposed communications system that could very well rival OFDM.