Abstract

Motivated by poor network connectivity
from moving vehicles, we develop a new loss recovery
method called opportunistic erasure coding (OEC). Unlike
existing erasure codingmethods, which are oblivious
to the level of spare capacity along a path, OEC transmits
coded packets only during instantaneous openings
in a path’s spare capacity. This transmission strategy ensures
that coded packets provide as much protection as
the level of spare capacity allows, without delaying or
stealing capacity fromdata packets. OEC uses a novel encoding
that greedily maximizes the amount of new data
recovered by the receiver with each coded packet. We
design and implement a system called PluriBus that uses
OEC in the vehicular context. We deploy it on two buses
for two months and show that PluriBus reduces the mean
flow completion time by a factor of 4 for a realistic workload.
We also show that OEC outperforms existing loss
recovery methods in a range of lossy environments.