Home // International Journal On Advances in Networks and Services, volume 2, number 2 and 3, 2009 // View article

Function Modulation – the Theory for Green Modem

Authors:
Subhendu Das
Nirode Mohanty
Avtar Singh

Keywords: information rates; sampling methods; orthogonal functions; communication; modulation.

Abstract:
Bandwidth of a digital communication channel is a valuable natural resource. Therefore it is important that the usage of this resource is minimized by carefully designing the digital modems. In this paper a new modulation scheme, called function modulation, is discussed that satisfies the Shannon’s model and therefore can help to save bandwidth by creating a green modem. It is also shown that all existing modulation methods based on sinusoidal functions do not meet the requirements of Shannon’s model and therefore have lower capacity for a given bandwidth. In addition, the paper shows that Shannon’s capacity is also not the limit. This capacity was derived under the assumption that the symbol duration is infinity. By relaxing this infinite time requirement much higher capacity is achieved. In order to derive this new capacity result a powerful and very well known mathematical concept, the infinite dimensionality of function space is used. It is shown that this concept can be the foundation of the digital communication as well as digital signal processing engineering.

Pages: 121 to 143

Copyright: Copyright (c) to authors, 2009. Used with permission.

Publication date: December 1, 2009

Published in: journal

ISSN: 1942-2644