  In this paper, we propose Transmission Control Protocol (TCP)-aware cross
layer scheduling algorithms in a multipoint-to-point network such as the uplink
of an IEEE 802.16 (WiMAX) network. Inadequate bandwidth allocation to a TCP
flow may lead to timeout and since TCP source drops its congestion window
($cwnd$) immediately after a timeout, it may affect the average throughput
adversely. On the other hand, since the TCP source increases its $cwnd$ only
linearly upon the availability of bandwidth, any excess assignment of bandwidth
may remain underutilized. The proposed scheduling algorithms address this by
allocating the resources based on $cwnd$ and TCP timeout. Moreover, since we
focus on uplink scheduling, we consider that only {\em flow} level resource
requirement is communicated to the Base Station ($BS$) instead of per {\em
packet} information. The schedulers also take into account the wireless channel
characteristics and are thus cross layer in nature. Through exhaustive
simulations, we demonstrate that the proposed schedulers exhibit enhanced
throughput and fairness properties when compared to that of Round Robin (RR)
scheduler under different shadowing. We demonstrate a gain between 3.5 \% to 15
\% in throughput and 15 \% to 25 \% in channel utilization over RR scheduler
under different shadowing.
