OFDM was invented at Bell Labs in the early 1960s. Anyway, one of their most litigated patents is as follows. >In a data communication system capable of

OFDM was invented at Bell Labs in the early 1960s. Anyway, one of their most litigated patents is as follows. >In a data communication system capable of variable rate transmission, high rate packet data trans- mission improves utilization of the forward link and de- creases the transmission delay. Data transmission on the forward link is time multiplexed and the base station transmits at the highest data rate supported by the for- ward link at each time slot to one mobile station. The data rate is determined by the largest C/I measurement of the forward link signals as measured at the mobile station. Upon determination of a data packet received in error, the mobile station transmits a NACK message back to the base station. The NACK message results in retransmission of the data packet received in error. The data packets can be transmitted out of sequence by the use of sequence number to identify each data unit within the data packets. That's the entire thing. No math, no "show your work". Just that paragraph.