Capacity of the AWGN Channel with Random Battery Recharges

摘要

We consider communication over the AWGN channel with a transmitter whosebattery is recharged with RF energy transfer at random times known to thereceiver. We assume that the recharging process is i.i.d. Bernoulli. Wecharacterize the capacity of this channel as the limit of an $n$-letter maximummutual information rate under both causal and noncausal transmitter knowledgeof the battery recharges. With noncausal knowledge, it is possible toexplicitly identify the maximizing input distribution, which we use todemonstrate that the capacity with noncausal knowledge of the battery rechargesis strictly larger than that with causal knowledge. We then proceed to deriveexplicit upper and lower bounds on the capacity, which are within 1.05bits/s/Hz of each other for all parameter values.