Juliana Freitag Borin

Simulator for WiMAX networks

Abstract The Network Simulator (ns-2) is a popular tool for the simulation of computer networks; it provides substantial support for simulation of Internet protocols over wired and wireless networks. Although some modules for WiMAX networks simulation have been proposed for the ns-2, none of them implements all MAC features specified by the IEEE 802.16 standard for bandwidth management and QoS support. This paper, however, does present the design and validation of a WiMAX module based on the IEEE 802.16 standard. The module implemented includes mechanisms for bandwidth request and allocation, as well as for QoS provision. Moreover, the implementation is standard-compliant.

Scheduler for IEEE 802.16 networks

The IEEE 802.16 standard was designed to support real-time and bandwidth demanding applications with quality of service (QoS). Although the standard defines a QoS signaling framework and five service levels, scheduling disciplines for these service levels are unspecified. In this paper, we propose a scheduling scheme for the uplink traffic which is fully standard-compliant and can be easily implemented in the base station. Simulation results show that this scheme is able to meet the QoS requirements of the service flows.

Uplink Scheduler and Admission Control for the IEEE 802.16 Standard

Although the IEEE 802.16 standard defines five service levels to support real-time and bandwidth demanding applications, admission control and scheduling mechanisms are not specified in the standard. This paper introduces an up-link scheduling algorithm and an admission control policy for IEEE 802.16 networks. The proposed solution is fully standard-compliant and can be easily implemented in the base station. Simulation results show that this solution is able to meet the QoS requirements of multimedia applications.

LTE time-domain uplink scheduler for QoS provisioning

This paper introduces a novel time-domain (TD) LTE uplink scheduler called Z-Based QoS Scheduler (ZBQoS) which is fully standard-compliant. The ZBQoS scheduler provides Quality of Service (QoS) requirements, supporting delay bound and guaranteed rate even when the network is heavily loaded. We evaluate the proposed scheduler under heterogeneous traffic and compare its performance to that of another TD scheduler, called Bandwidth and QoS Aware (BQA), recently proposed. Simulation results show that ZBQoS scheduler reduces significantly delay of real-time traffic, while it is able to maintain lower packet loss ratio (PLR), when compared with the performance of the BQA scheduler which greatly surpasses the recommended PLR value under heavily loaded scenarios.

A Standard-Compliant Scheduler for WiMAX Networks

In order to support real-time and bandwidth demanding applications, the IEEE 802.16 standard is expected to provide quality of service (QoS). Although the standard defines a QoS signaling framework and five service levels, scheduling mechanisms for this network are unspecified. In this paper, we propose a scheduling scheme for the uplink traffic which is fully standard-compliant and can be easily implemented in the base station. Simulation results show that this scheme is able to meet the QoS requirements of the service flows.

Opportunistic Cross-Layer Uplink Scheduler for the IEEE 802.16 Standard

Scheduling is an essential mechanism in IEEE 802.16 networks for distributing the available bandwidth among the active connections so that their quality of service requirements can be furnished. Scheduling mechanisms adopted in wired networks, when used in wireless networks lead to inefficient use of the bandwidth since the location dependent and time varying characteristics of the wireless link usually are ignored by the wired networks. This paper introduces a standard compliant cross-layer scheduling mechanism which considers the modulation and coding of each mobile station to increase the efficiency of channel utilization while furnishing the QoS requirements of the connections.

Admission control for WiMAX networks

This paper introduces admission control policies for WiMAX networks, which aim to reach three main goals: restrict the number of simultaneous connections in the system so that the resources available for the uplink scheduler are sufficient to guarantee the quality-of-service requirements for each connection, support the service provider expectations by maximizing the revenue, and maximize user satisfaction by granting additional resources. The optimal solution to meet these goals is non-deterministic polynomial-time hard and therefore cannot be solved in acceptable polynomial time. For this reason, both optimal and polynomial time heuristic solutions are introduced. Simulation experiments are used to evaluate and compare the proposed policies. Copyright

Admission Control Policies for Revenue and Utility Maximization in IEEE 802.16 Networks

This paper introduces admission control policies for the IEEE 802.16 standard which aim to reach three main goals: restrict the number of simultaneous connections in the system so that the resources available to the scheduler are sufficient to guarantee the QoS requirements of each connection, support the service provider expectations by maximizing the revenue, and maximize the users satisfaction by granting them additional resources. The proposed policies are evaluated through simulation experiments.

LTE scheduler for LTE/TDM-EPON integrated networks

This paper introduces a novel LTE uplink scheduler called Hybrid Z-Based QoS Scheduler (HZBQoS), a fully standard-compliant LTE scheduler designed to operate in ONU-eNB devices of integrated LTE/TDM-EPON networks. The HZBQoS scheduler provides delay bound and guaranteed rate even when the backhaul and mobile network are heavily loaded. We evaluated the proposed scheduler under heterogeneous traffic and compared its performance to that of another LTE uplink scheduler, called Z-Based QoS Scheduler (ZBQoS), which does not take into account the variability of the backhaul link capacity. Simulation results show that HZBQoS is able to provide QoS requirements in the integrated network and outperforms the ZBQoS scheduler.

Cross-Layer Uplink Scheduler for the IEEE 802.16 Standard

The IEEE 802.16 standard for broadband wireless access is a low cost solution for Internetaccess in metropolitan and rural areas. Although it defines five service levels to support real-time and bandwidth demanding applications, scheduling mechanisms are not specified in the standard. Due to the wireless channel variability, scheduling mechanisms widely studied for wired networks are not suitable for IEEE 802.16 networks. This paper proposes an uplink cross-layer scheduler which makes bandwidth allocation decisions based on information about the channel quality and on the Quality of Service requirements of each connection. Simulation results show that the proposed scheduler improves the network performance when compared with a scheduler which does not take into account the channel quality.