Broadcasting over uncertain channels with decoding delay constraints

We examine communication over slowly varying flat-fading additive white Gaussian noise (AWGN) channels with delayed channel state information (CSI) feedback to the transmitter and finite decoding delay constraints. Under a block-fading channel model, it is shown that a broadcast strategy maximizes the expected reliably received rate when the decoding delay constraint is one block and in certain cases when the delay constraint is two blocks. The latter requires a new analysis of underlying parallel Gaussian broadcast channels (GBCs) which are not degraded in the same direction