Romain Rollet

Resource allocation and wireless scheduling scheme for a HiperLAN/2 system

In this paper, a dynamic resource allocation scheme for a wireless local area network system is presented. It aims at enforcing the Quality of Service requirements of the applications that are carried on the wireless link even when errors occur on it. The allocation takes benefit from the coexistence of connections that have different QoS tolerances so that, when facing errors, the bandwidth allocated to the more tolerant connections could be reduced and attributed to the connection with more stringent QoS requirements to perform retransmissions. For that purpose, two classes of Quality of Service are considered that are related to Constant Bit Rate traffics and best-effort traffics. The scheduling framework is then based on a hierarchical rate-based fair queuing algorithm and is extended in order to cope with error. To illustrate its operation, the proposed scheme is applied to the ETSI HiperLAN/2 WLAN. Some simulation results are reported and show the impact of the scheduling principles on best-effort traffics such as TCP applications and its actual benefits for CBR traffic. The efficiency of the proposed mechanism is evaluated using measurement of delays and throughputs at Data Link Layer level. The aim of this paper is not so much to prove the fairness of this mechanism but rather its ability to guarantee negotiated services required by heterogeneous applications.