| Abstract |
A significant body of recent research has analyzed
the problematic behavior of TCP over wireless links, and a
plethora of modifications to TCP have been proposed in order
to increase its performance in such contexts. Two schools of
thought have emerged: the first proposes changes to the end-toend
protocol, while the second explores the potential to enhance
lower layers as a means to improve the end-to-end performance
of TCP. This paper focuses on the latter, and in contrast to
most research in this area, which thus-far has concentrated on a
single TCP flavor, examines the case where different TCP flavors
are competing over a wireless link. To this end, we present and
assess a cross-layer solution that involves the adaptation of lower
layer characteristics (i.e., the coding rate) based on the detected
TCP flavor, in order to maximize the fairness among TCP flows.
Through extensive numerical investigations, we show that the
proposed scheme considerably improves the fairness over wireless
links among different TCP flavors. Our approach also has a
minimal effect on the aggregate throughput of the TCP flows,
and in cases where the packet error rate is very low, has a small
positive effect on throughput. |