Date Added: Oct 2010
Hybrid Automatic Retransmission reQuest (HARQ) is widely adopted in wireless communication systems to improve the link level and system level throughput. Adaptively selecting retransmission based on the received packet can further improve the system performance by reducing the retransmission overhead. To this end, this paper first introduces the concept of Instantaneous Packet Information (IPI). Then, a new metric is proposed to evaluate the quality of received packets based on IPI. The most important feature of the IPI metric is its in-sensitivity to channel fading. Therefore, it can be used in practice, where channel varies significantly. Furthermore, this paper introduces an IPI-metric based HARQ (IPI-HARQ) featuring an on-demand adaptive retransmission.