On the Capacity of the Multiuser Vector Adder Channel

We investigate the capacity of the Q-frequency Suser vector adder channel (channel with intensity information) introduced by Chang and Wolf. Both coordinated and uncoordinated types of transmission are considered. Asymptotic (under the conditions Q → ∞, S = γQ and 0 < γ < ∞) upper and lower bounds on the relative (per subchannel) capacity are derived. The lower bound for the coordinated case is shown to increase when γ grows. At the same time the relative capacity for the uncoordinated case is upper bounded by a constant.