Patent ID: 7839851

Claim:
An apparatus for use in a wireless multicast system having a plurality of receivers, the apparatus comprising: a storage to store at least one of channel state and rate information received from the plurality of receivers; a transmitter to broadcast information over a broadcast channel to receivers in the plurality of receivers for each transmission time slot; and a controller coupled to the storage and the transmitter to adapt transmission rates of the transmitter to cause the transmitter to transmit at different rates for different transmission time slots, wherein the controller operable to: determine a subset of receivers from a sorted list of the plurality of receivers for each transmission time slot, where the sorted list is sorted based on achievable rates of each receiver for said each transmission time slot, the subset of receivers being those receivers targeted to reliably receive a broadcast transmission over the broadcast channel during said each transmission time slot given channel state information history, and set a transmission rate at which the transmitter broadcasts the information in a multicast manner to the subset of receivers, based on the channel state information associated with the broadcast channel and received from the plurality of receivers and based on the subset of receivers, the transmission rate being the lowest achievable rate for receivers in the subset of receivers, so that receivers in the subset of receivers can successfully recover the broadcast information for said each transmission time slot while receivers of the plurality of receivers not in the subset of receivers are allowed to observe block erasures in said each transmission time slot, and wherein the controller comprises an encoder to generate encoded blocks from the broadcast information for said each transmission time slot, using one of a group consisting of a fixed rate erasure code and a rateless code, so that the broadcast information can be recovered by all the receivers of the plurality of receivers after receiving a suitable number of encoded blocks against the erasures caused by targeting different subsets of receivers across different time slots and further wherein the transmitter is to transmit the encoded blocks to the subset of receivers.