(100 امتیاز از 29 رای)
Loading...
پروژه چارچوب های QoS تعاملی برای شبکه های وایمکس ثابت با شبیه ساز NS2
An interactive QoS framework for fixed WiMAX networks
چکیده مقاله:
The IEEE 802.16 standard defines several scheduling classes at MAC layer for preferential treatment of service flows depending on QoS requirements specific to a service flow. In this paper, a new framework has been proposed to solve and address QoS issues for fixed point to multipoint (PMP) 802.16 systems. The proposed framework consists of a uplink scheduler and Call Admission Control (CAC) module. The proposed CAC module interact with the uplink scheduler status and makes its decision based on the scheduler’s queues status. Extensive OPNET simulation demonstrates the effectiveness of the proposed framework.
Keywords: WiMAX, QoS, Scheduler, Connection Admission Control, OPNET
http://www.sciencedirect.com/science/article/pii/S1569190X09001713
Introduction:
In today’s market, Subscribes Stations demand multimedia services and it is network provider’s responsibility to satisfy these requests with the respective quality of services. WiMAX network [13] is viewed as one of the technology to satisfy such demand at a lower cost and fast deployment. Also known as IEEE 802.16 standard , WiMAX is defined as the ‘‘last mile” technology to provide broadband wireless access in urban and rural areas. In comparison to the existing technologies, WiMAX presents many advantages as flexibility, service up to almost 30 miles; data throughput of up to 70 Mbps and provides fast service.
The standard defines different evolutions; in April 2002, IEEE 802.16 was the first standard to specify line of sight (LOS) transmission using 10–66 GHz radio frequency. In January 2003, an enhanced evolution, IEEE 802.16a was defined to support non-line of sight (NLOS) services at a frequency range between 2 and 11 GHz. IEEE 802.16d was published in 2004 to specify fixed wireless access. The IEEE 802.16e version was revised in October 2004 to be released in 2005 with considerable enhancement and mobility support as the primarily application.
WiMAX technology addresses two modes of operation, point to multipoint (PMP) topology where the base station is connected to various subscribers for a provision of more than one connection and mesh topology whose connection can be established between two subscribers without any intermediate base station. Unlike the Open System Interconnection Reference Model (OSI) model, WiMAX standard specifies two layers to name PHY and MAC.
The PHY layer which is also known as the transport layer is mainly used to transport data and serves as an interface between upper layer and external medium. It specifies five technologies as described below:
1. WirelessMAN-SC: single carrier applied for line of sight.
2. WirelessMAN-SCa: used for non-line of sight in licensed band.
هیچ نظری ثبت نشده است