Degraded Broadcast Channel With Secrecy Outside a Bounded Range

The K-receiver degraded broadcast channel with secrecy outside a bounded range is studied, in which a transmitter sends K messages to K receivers, and the channel quality gradually degrades from receiver K to receiver 1. Each receiver k is required to decode message W1, ..., Wk, for 1 ≤ k ≤ K, and to be kept ignorant of Wk+2, .. ., WK, fork = 1, ..., K -2. Thus, each message Wk is kept secure from...