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The global optimization of phase-incoherent signals

Citation

Schaffner, Charles Albert (1968) The global optimization of phase-incoherent signals. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:12212015-144937012

Abstract

The problem of global optimization of M phase-incoherent signals in N complex dimensions is formulated. Then, by using the geometric approach of Landau and Slepian, conditions for optimality are established for N = 2 and the optimal signal sets are determined for M = 2, 3, 4, 6, and 12.

The method is the following: The signals are assumed to be equally probable and to have equal energy, and thus are represented by points ṡi, i = 1, 2, …, M, on the unit sphere S1 in CN. If Wik is the halfspace determined by ṡi and ṡk and containing ṡi, i.e. Wik = {ṙϵCN:| ≥ | ˂ṙ, ṡk˃|}, then the Ʀi = ∩/k≠i Wik, i = 1, 2, …, M, the maximum likelihood decision regions, partition S1. For additive complex Gaussian noise ṅ and a received signal ṙ = ṡie + ṅ, where ϴ is uniformly distributed over [0, 2π], the probability of correct decoding is PC = 1/πN ∞/ʃ/0 r2N-1e-(r2+1)U(r)dr, where U(r) = 1/M M/Ʃ/i=1 Ʀi ʃ/∩ S1 I0(2r | ˂ṡ, ṡi˃|)dσ(ṡ), and r = ǁṙǁ.

For N = 2, it is proved that U(r) ≤ ʃ/Cα I0(2r|˂ṡ, ṡi˃|)dσ(ṡ) – 2K/M. h(1/2K [Mσ(Cα)-σ(S1)]), where Cα = {ṡϵS1:|˂ṡ, ṡi˃| ≥ α}, K is the total number of boundaries of the net on S1 determined by the decision regions, and h is the strictly increasing strictly convex function of σ(Cα∩W), (where W is a halfspace not containing ṡi), given by h = ʃ/Cα∩W I0 (2r|˂ṡ, ṡi˃|)dσ(ṡ). Conditions for equality are established and these give rise to the globally optimal signal sets for M = 2, 3, 4, 6, and 12.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Electrical Engineering
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Grettenberg, Thomas L.
Thesis Committee:
  • Unknown, Unknown
Defense Date:23 April 1968
Record Number:CaltechTHESIS:12212015-144937012
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:12212015-144937012
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9342
Collection:CaltechTHESIS
Deposited By: Leslie Granillo
Deposited On:22 Dec 2015 17:37
Last Modified:22 Dec 2015 17:37

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