1 research outputs found
Optimality and Rate-Compatibility for Erasure-Coded Packet Transmissions when Fading Channel Diversity Increases with Packet Length
A message composed of packets is transmitted using erasure and channel coding
over a fading channel with no feedback. For this scenario, the paper explores
the trade-off between the redundancies allocated to the packet-level erasure
code and the channel code, along with an objective of a low probability of
failure to recover the message.
To this end, we consider a fading model that we term proportional-diversity
block fading (PD block fading). For a fixed overall code rate and transmit
power, we formulate an optimization problem to numerically find the optimal
channel-coding rate (and thus the optimal erasure-coding rate) that minimizes
the probability of failure for various approximations of the problem.
Furthermore, an interpretation of the results from an incremental redundancy
point of view shows how rate-compatibility affects the possible trajectories of
the failure probability as a function of the overall code rate. Our numerical
results suggest that an optimal, rateless, hybrid coding scheme for a
single-user wireless system over the PD block-fading channel should have the
rate of the erasure code approach one.Comment: 6 pages, 4 figure