An advance over the prior art is achieved through an efficient method to
retransmit erroneous frames by identifying the users who are most likely
to experience a frame error and requests retransmissions from them. Since
the recovery is done by starting with the most likely, second most likely
etc., the invention results in faster recovery of data. Moreover, the
invention reduces the battery consumption of subsequent mobile nodes by
suppressing the retransmission requests that were already made by nodes
preceding it. A key element of the invention is to rank the set of
receiver nodes in the order of decreasingly worse channel conditions,
i.e., from worst to best. Hence, with K receiver nodes, a transmit node
assigns rank 1 to a receiver node to which it has the poorest radio
channel condition. Similarly, it assigns rank K to the receiver node to
which it has the best radio channel condition. The channel condition is
known at the receiver by keeping a simple measure of the number of data
frames correctly received so far and the total number of frames
transmitted to it. This information can be periodically sent back to the
transmitter and thus aiding in the ranking procedure. Alternatively, if
the transmitter is capable of sending a pilot/beacon, the receiver can do
some averaging of received signal strength and provide such information
back to the transmitter.