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SUMMARY:Optimum resource allocation in MIMO systems: An information theore
 tic-estimation theoretic approach - Dr Miguel R. D. Rodrigues\, University
  of Porto\, Portugal
DTSTART:20071119T110000Z
DTEND:20071119T120000Z
UID:TALK9230@talks.cam.ac.uk
CONTACT:Ioannis Chatzigeorgiou
DESCRIPTION:A large body of optimization problems abound in the telecommun
 ications field\, particularly enticing ones relating to resource optimizat
 ion in communication systems. In this talk\, we will consider power alloca
 tion optimization problems in multiple-input multiple-output (MIMO) Gaussi
 an channels with arbitrary discrete inputs\, that represent a large number
  of relevant communications scenarios such as multiple antenna systems\, c
 ode division multiple access (CDMA) systems or digital subscriber line (DS
 L) systems.\n\nWe capitalize on the recently discovered relationship betwe
 en mutual information and minimum mean-squared error (MMSE) to determine t
 he power allocation strategy that maximizes the mutual information between
  the system input and output. We also put forth a novel mercury-waterfilli
 ng interpretation of the optimal power allocation procedure that generaliz
 es the conventional waterfilling interpretation applicable to parallel ind
 ependent Gaussian channels with Gaussian inputs as well as the conventiona
 l mercury-waterfilling interpretation applicable to parallel independent G
 aussian channels with arbitrary inputs. Subsequently\, we exploit the mutu
 al information-MMSE relationship to specialize the optimal power allocatio
 n strategy to the asymptotic regimes of low- and high-SNR.\n\nOf particula
 r relevance\, we demonstrate that in the high-power regime the power alloc
 ation strategy that maximizes mutual information also maximizes the minimu
 m distance of the output lattice\, hence minimizes the error probability. 
 We also investigate the form of the optimal precoding policy for MIMO chan
 nels with arbitrary discrete inputs.\n\nFinally\, we show that the techniq
 ues have the potential to significantly increase the transmission rate of 
 current systems\, namely Gigabit DSL systems.\n\n_This represents joint wo
 rk with Fernando Perez-Cruz and Sergio Verdú of Princeton University._
LOCATION:Computer Laboratory\, William Gates Building\, Room SS03
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