Applying active queue management to link layer buffers for real-time traffic over third generation wireless networks

Wireless channels have the characteristic that the link quality varies with propagation conditions. For real-time flows with hard time deadlines, link layer retransmissions over the wireless network due to fluctuations in link quality may result in many packets being dropped due to deadline expiry. The expired packets waste network resources and lead to long queuing delay for subsequent packets. In this paper, we propose to use active queue management to limit the transmission queue length and hence queuing delay, thus eliminating expiration packet drops. This allows the buffer and wireless bandwidth that would otherwise be wasted by expiring packets to be released earlier for other packets. We apply this mechanism to the radio link control layer in third generation wireless networks. The effectiveness of the proposed mechanism is verified by simulations.