Channel condition self-clocked packet scheduling scheme for wireless networks

Abstract

Since mobile hosts suffer from burst and location-dependent channel errors in wireless networks, packet fair queueing algorithm in wireline networks cannot be applied directly to wireless networks. Generally, a fair scheduler in a wireless network retains the virtual time of flow when the flow encounters channel errors. This results to the flow having higher priority when it exits from errors, and the system can compensate the lost service for the flow. This causes the lagging flows to capture the shared channel and affects the queueing delay of flows perceiving a clean channel. In this paper, we present a channel condition self-clocked packet scheduling scheme. This algorithm can address the problem and achieve the following goals: (1) steady delay and jitter for flows perceiving an error-free environment, (2) delay and throughput guarantees in an error-free environment, (3) short-term fairness among flows perceiving an error-free environment, and (4) long-term fairness for error system. Our algorithm is based on start-time fair queueing, and the virtual time of flows is reset to contend for forwarding its packet the next time when errors happen for the flow.

Bandwidth Allocation Scheduling Algorithms for IEEE 802. 16 WiMax Protocol to Improve QoS: A Survey

“…Then it creates virtual slots and shares their slots in LIFS. LIFS is limited by service rate and does not receive additional services [15].…”

“…Let Rk(t) denote the instantaneous data rate that user k can achieve at time t, and let Tk(t) be the average throughput for user k up to time slot t. The PFS scheduler selects the user, denoted as k*, with the highest Rk(t)/Tk(t)for transmission. In the long term, this is equivalent to selecting the user with the highest instantaneous rate relative to its mean rate [15].…”