On the Capacity of Generalized Ising Channels

Nearly tight lower and upper bounds on the capacity of generalized Ising channels are presented. For the case where feedback is allowed, a closed-form expression for the capacity is found for channel error probability p ∈ [0, p0], where p0 ≈ 0.398324. A near-capacity-achieving family of encoders is presented for the values p ∈ [0, p0]. Two lower bounds on that capacity for larger values of p are presented, one of which is tight on the interval [p0, 0.5].