Asynchronous network coding has the potential to
improve wireless network performance compared with simple
routing. However, to achieve the maximum network coding gain,
the encoding node consumes a few computing and storage
resources that may be unaffordable for wireless sensor networks
such as CubeSats. An analogous threshold strategy, called Best
Effort Network Coding (BENC), which requires only minimal
storage resources and no computing resources, is investigated in
this paper as an efficient and convenient method of network
coding. In this strategy, a new packet arrival evicts the head
packet when the queue is full to avoid excessively long waits.
Moreover, in contrast to other methods that require a queue for
each flow, the BENC uses only one queue for the two coded flows.
In addition, the problem of time interval distribution for the
output flow, which combines two independent flows, is
investigated, and the network coding gain is then analyzed. While
the maximum coding gain requires infinite buffer capacity under
two independent Poisson arrivals with the same transmission
rates, calculation results show that the BENC needs only 4 buffers
to achieve 90% of the maximum coding gain and can reach 99%
of the maximum coding gain using 50 buffers. These results are
verified by numerical simulations.