An Optimal FEC Based Solution to Head-of-Line Blocking

Head-of-Line (HOL) Blocking is a well known cause of performance
degradation due to missing packets resulting in latency
not only for themselves but also to dependent packets
which have already arrived. Many existing approaches attempt
to alleviate the issue by removing dependencies between
packets so that packets which have already arrived
have a lower chance of being delayed due to other packets
which are missing. Other complimentary approaches use adhoc
proactive retransmission or error correction to lower the
probability of loss itself. In this paper, we show how application
dependent requirements can be used in conjunction
with network parameter estimates to provide an optimal approach
to proactive retransmissions or error correction. In
this approach, using network parameter estimates of bandwidth,
delay, and loss, we first mathematically derive a probability
distribution of the per packet delay which is then used
to optimize parameters in a forward error correction framework
given application requirements.