ARROW: An efficient traffic scheduling algorithm for IEEE 802.11e HCCA

In this paper we present a novel traffic scheduling algorithm for IEEE 802.11e, referred to as ARROW(Adaptive Resource Reservation Over WLANs), which aims at providing improved performance for the support of multimedia traffic. The novel characteristic of this algorithm, compared to previous proposals, is that it performs channel allocations based on the actual traffic buffered in the various mobile stations, i.e., on the exact transmission requirements. This feature renders ARROW ideal for variable bit rate traffic. However, an enhancement is also presented that improves ARROW performance under constant bit rate traffic. The ARROW algorithm and its enhancement are discussed and evaluated against two other schedulers found in the open technical literature, namely the Simple Scheduler and SETT-EDD. Results from a detailed simulation model verify that ARROW provides much better channel utilization and considerably improved performance, in terms of mean delay and packet loss. © 2006 IEEE

A centralized approach to dynamic channel assignment in wireless ATM LANs

A centralized approach for Dynamic Channel Assignment (DCA) in wireless ATM system is presented. The proposed approach applies to structured wireless ATM LANs, where base stations act as hubs to offer wireless access to mobile units. An IntrAdomain DCA entity (IADCA) is introduced for the dynamic assignment of resources to the requesting base stations, taking into account mutual interference constraints and current resource usage. The IADCA entity is based on two different reservation disciplines and multiple assignment policies when candidate carriers are available. Simulation results for a number of scenarios are presented to assess the performance of the proposed approach

Supporting UMTS QoS in Wireless LANs

This paper focuses on how the UMTS Quality of Service (QoS) architecture can be supported in Wireless LANs (WLANs), deployed as alternative access networks to the UMTS core. More specifically, the paper addresses the provision of UMTS QoS over WLANs and proposes a solution based on the introduction of the Wireless Adaptation Layer (WAL). The WAL provides means for extending the UMTS QoS in WLAN environments, independently of the underlying WLAN technology. Moreover, the WAL configuration to support the provisioning of UMTS QoS is discussed. In this context, a mapping between UMTS QoS attributes and WAL modules is proposed and justified. © IFIP International Federation for Information Processing 2003

On the support of voice call continuity across UMTS and wireless LANs

In this paper, we address the architecture and the procedures that can enable voice call handover from UMTS to WLAN and we also study how efficiently the WLAN can support the voice calls transferred from UMTS. Our study is based on a practical simulation model that lets us quantify the maximum number of voice calls that can be handed over from UMTS to WLAN, subject to maintaining the same level of UMTS QoS and respecting some WLAN policies. In addition, several other voice call performance metrics are derived. Our results indicate that an IEEE 802.11e access point can support a limited number of voice calls handed over from UMTS, which depends primarily on the applied WLAN bandwidth sharing policy (i.e., how the bandwidth is shared between WLAN voice and data users) and the QoS requirements. The performance of the WLAN scheduling algorithm is also of paramount importance and in our study we consider the so-called ARROW scheduler. Although the simulation results are derived for a specific bandwidth sharing policy, they can readily be scaled and provide practical upper bounds for the number of UMTS voice calls that can be seamlessly admitted to a WLAN access point. Copyright © 2007 John Wiley & Sons, Ltd

Traffic scheduling in wireless ATM networks

Wireless ATM is enjoying enormous research interest in the last few years, because of its ability to combine multimedia applications support, together with the, freedom of mobility. One of the key design issues is the medium access control (MAC) protocol for the radio interface. This paper presents the traffic scheduling algorithm used in the MAC protocol of the Wireless ATM Network Demonstrator (WAND) system being developed within project Magic WAND. Magic WAND is investigating wireless ATM technology for customer premises networks in the framework of the Advanced Communications Technologies and Services (ACTS) programme, funded by the European Union. The proposed algorithm is delay oriented to meet the requirements of the various traffic classes defined by the ATM architecture. Simulation results are presented to assess the performance of the algorithm