RELIABILITY OF QUANTUM-MECHANICAL COMMUNICATION SYSTEMS.
Abstract
The investigation was concerned with the detection of a set of M messages that are transmitted over a channel disturbed by chaotic thermal noise when quantum effects in the communication systems are taken into account. Attention was restricted to the special case in which the density operators specifying the states of the received field are commutative. From quantum-mechanical description of the noise and signal fields, the structure and performance of the quantum-mechanical optimum receiver are found. Two special communication systems were studied: (1) a system in which signals have known classical amplitudes but unknown absolute phases, and the signal field is in coherent states; (2) a system in which the classical amplitudes of the signal field are Gaussian random processes, and the received field in the absence of noise is in completely incoherent states. Bounds on the probability of error in these systems were derived. For both systems, the minimum attainable error probability is expressed in the form exp(-tau CE(R)), where E(R) is the system reliability function which is a function of the information rate R of the system, tau is the time allotted for the transmission of a message, and C is the capacity of the system. For these two types of systems, the expressions for C and E(R) are derived. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1968
- Accession Number
- AD0682655
Entities
People
- Jane Win-shih Liu
Organizations
- Massachusetts Institute of Technology