Spread Spectrum Multi-h Modulation
Abstract
The possibility of communicating reliably by electromagnetic radiation, with only an intended party receiving the message, has long challenged engineers to devise techniques, such as spread spectrum modulation, to combat unintended detection. Coincidently, the constraints of the electromagnetic spectrum have led to the use of bandwidth and power efficient modulation schemes such as continuous phase modulation and multi-h modulation. The analysis contained herein is the first theoretical and numerical characterization of the combination of direct sequence spread spectrum techniques with multi-h continuous phase modulation; thereby yielding a new class of signals collectively referred to as spread spectrum multi-h (SSMH) modulated signals. By applying a pseudorandom direct spreading sequence to a digital information sequence prior to multi-h modulation, a unique communication scheme is created whereby control over the transmitted spectrum is afforded so as to have a signal with a low probability of intercept by an unintended receiver. In the process of defining and characterizing the signaling structure, it is shown for the first time that the cyclic modulation indices can be applied on either a chip or on a bit interval basis with distinct signal structure and performance differences. It is also shown for the first time that there is a close resemblance between the power spectral densities of the two techniques. These results provide a unique design flexibility for the system engineer. Theses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1988
- Accession Number
- ADA199473
Entities
People
- William D. Lane
Organizations
- United States Military Academy