Enhancing throughput over wireless LANs using channel state dependent packet scheduling

TLDR

Wireless LANs suffer from burst errors that cause repeated packet losses, leading to retransmission failures, poor channel utilization, and HOL blocking when multiple sessions share the link. The study proposes channel‑state‑dependent packet scheduling to adapt dispatching decisions to wireless channel conditions. The authors compare several CSDP scheduling methods to improve transport‑layer session performance. Using a CSDP scheduler at the device‑driver level significantly improves channel utilization in typical wireless LAN setups.

Abstract

Unlike wired networks, packets transmitted on wireless channels are often subject to burst errors which cause back to back packet losses. Most wireless LAN link layer protocols recover from packet losses by retransmitting lost segments. When the wireless channel is in a burst error state, most retransmission attempts fail thereby causing poor utilization of the wireless channel. Furthermore, in the event of multiple sessions sharing a wireless link, FIFO packet scheduling can cause the HOL blocking effect, resulting in unfair sharing of the bandwidth. This observation leads to a new class of packet dispatching methods which explicitly take the wireless channel characteristics into consideration in making packet dispatching decisions. We compare a variety of channel state dependent packet (CSDP) scheduling methods with a view towards enhancing the performance of the transport layer sessions. Our results indicate that by employing a CSDP scheduler at the wireless LAN device driver level, significant improvement in the channel utilization can be achieved in typical wireless LAN configurations.