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Unformatted text preview: ECE 562 Fall 2011 October 10, 2011 HOMEWORK ASSIGNMENT 4 Due Date: October 18, 2011 (in class) 1. “SemiOrthogonal” Signal Set. Consider the signal set with M = 2 N signals given by: s m ( t ) = √ E g m ( t ) m = 1 ,...,N j √ E g m N ( t ) m = N + 1 ,...,M. where { g k ( t ) } N k =1 are realvalued orthonormal functions. Clearly this signal set satis fies: Re [ ρ k,` ] = 0, for k 6 = ` . (a) Argue that R k = h r ( t ) ,g k ( t ) i ,k = 1 ,...,N , form sufficient statistics for optimal decision making at the receiver for an AWGN channel. (b) Now define the M realvalued statistics y m = r m,I m = 1 ,...,N r ( m N ) ,Q m = N + 1 ,...,M. Show that the MPE decision rule is given by ˆ m MPE = arg max m y m (c) Find an expression for P e for the MPE decision rule 2. In this problem you will show the following result for Mary orthogonal modulation lim M →∞ P c = 1 γ b > ln 2 γ b < ln 2 where P c is the probability of correct decision making. Recall that we showed in class that P c = Z ∞∞ h 1 Q ( x + p 2 γ b log 2 M ) i M 1 1 √ 2 π e x 2 / 2 dx (a) Show that for any...
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 Fall '09
 Decision Making, phase error, V.V. Veeravalli, linearly modulated signals

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