A type-I hybrid ARQ protocol over optimal-sequence CDMA link
Tan F. Wong, Li Gao, Tat-Ming Lok · 2002
It has been shown that the capacity of a CDMA link can be significantly enhanced by optimally selecting or adapting the set of spreading sequences employed under the constraint that a prescribed level of SNR performance is achieved. We propose a type-I hybrid ARQ protocol which makes use of the optimally selected spreading sequences in the physical layer to allow simultaneous transmission of multiple packets over a CDMA link. Packets are divided into two classes, namely retransmission packets and newly arrived packets. Packets in each class are assigned optimally selected spreading sequences and a target SNR. With proper choices of the number of packets to be transmitted and the SNR targets in each time slot, the proposed type-I hybrid ARQ protocol provides significant improvement on the link throughput, particularly when the transmission power is abundant.