Fuzzy Based Flow Management of Real-Time Traffic for Quality of Service in WLANs

Abstract

Designing heterogeneous bandwidth limited communication systems that support a wide variety of applications, including file transfer, web browsing, interactive games, audio and video calls, and emerging real-time virtual world and social media applications is a challenging task because there is a shortage of resources to satisfy all traffic demands and diverse quality of service (QoS) requirements. For example, the current Internet architecture supports only best-effort service class which is not enough especially for delay sensitive real-time multimedia applications. Therefore, to improve QoS for specified traffic in the Internet, the end nodes (hosts) should make a bandwidth reservation through all the intermediate nodes, like access points and routers, by using some sort of resource reservation. For the QoS guarantee, the IETF has worked on the resource reservation protocol (RSVP) that can be used to hard resource reservation: an endpoint uses RSVP to request a simplex flow through the network with specified QoS bounds and the intermediate nodes, like routers, along the path either agree to honor the request or deny it. It is a transport layer protocol designed to reserve resources across a network. RSVP operates over an internet protocol versions 4 or 6 (IPv4 or IPv6) and provides receiver-initiated setup of resource reservations for multicast or unicast data flows. The drawback of the RSVP is that all the routers along the path must agree the resource reservation for QoS guarantee. However, no any QoS system can satisfy all users’ demands if the network traffic exceeds network capacity. Another disadvantage is that the reserved virtual links do not necessarily use the network capacity optimally. Therefore, we focus here to the cognitive flow management of delay sensitive constant bit rate real-time traffics, such as voice over internet protocols (VoIP), video calls, and interactive games, to improve QoS in Wireless Local Area Networks (WLANs). The Internet has two independent flow problems. Internet protocols need end-to-end flow control and a mechanism for intermediate nodes, like routers and access points, to control the amount of traffic known as the congestion prevention and control mechanism. Flow control is closely related to the point-to-point traffic between a sender and a receiver. It guarantees that a fast sender cannot continually send datagrams faster than a receiver can absorb them. Congestion is a condition of severe delay caused by an overload of datagrams at intermediate nodes. Usually congestion arises for two different reasons: a high-speed computer may be able to generate traffic faster than a network can transfer it or many computers send datagrams simultaneously through a single router, even though no single computer causes the problem. Hence, the congestion control can be considered more as a global issue whereas 18