Gaussian multiple-access channels with weighted energy constraint

The Gaussian multiple-access channel with weighted energy constraint E~/sub sum/=/spl Sigma//sub k/E/sub k//|d/sub k/|/sup 2/ models the situation in cellular multiuser communication more accurately than the standard approach with d/sub k/=1,/spl forall/k. The minimum weighted sum energy E~/sub sum/ is shown to be only achievable at a unique energy tupel (E/sub 1/, ..., E/sub K/), if all weights differ in amplitude. Moreover, the theory is generalized to a multiple receiver system describing cellular communication systems with optimum multiple cell-site processing. While for single-receiver systems the optimum energy tupel is a vertex of the allowed energy region, i.e. successive cancellation is possible, for a multi-receiver system this does not hold in general.