wifi与wimax基础

The 2011 Military Communications Conference - Track 5 - Communications and Network Systems
Performance Analysis of an Integrated Wireless Network Using WiMAX as Backhaul Support for WiFiRecent advances in wireless communications have expanded more access technologies such as WiFi (IEEE 802.11a/b/g/n) [1] in the local area and WiMAX (IEEE 802.16e) [2] in the metropolitan area, besides the traditional cellular access technology in the wide area. While the benefits of WiFi and WiMAX are both obvious, they are two different technologies catering for different needs. WiFi is a cheap solution aimed to cover short distances, such as airport, hotels, and conference areas; while WiMAX is the next-generation of wireless technology that is relatively expensive and aimed to cover long distances. Furthermore, the WiMAX network may be a promising solution to provide backhaul support for WiFi hotspots. Much research about the integrated WiFi and WiMAX networks has been developed in the past a few years. In [3], an integrated WiMAX/WiFi network was considered where the licensed WiMAX spectrum is shared by the WiFi access points (APs) to provide Internet connectivity to WiFi users. A model for optimal pricing for bandwidth sharing was proposed in an integrated WiMAX/WiFi network. In [4], an integrated architecture utilizing a novel WiMAX/WiFi access point (W2AP) device was proposed to effectively combine the WiMAX and WiFi technologies, where the protocol operation of the WiFi hotspots is the same as that of the WiMAX system, and thus the WiFi network can support connection-oriented transmissions and QoS in a similar fashion to the WiMAX system. In [5], the application of integrated IEEE 802.16/ WiMAX and IEEE 802.11/WLAN broadband wireless access
Shensheng Tang
Department of Engineering Technology Missouri Western State University St. Joseph, MO 64507, USA
Abstract—We propose an analytic model using WiMAX as backhaul support for WiFi traffic and evaluate the system performance. One unique feature is that the WiFi traffic completely reflects the realistic user behavior. A WiFi user may be overflowed to its overlaid WiMAX cell when it is rejected at the WiFi cell; the WiFi user may also work for some time duration in the WiFi cell and then make a vertical handoff to its overlaid WiMAX cell when it needs to move from its current WiFi cell (e.g., office) to its target WiFi cell (e.g., airport). Further, the target WiFi cell may be located at another place in the same WiMAX cell, or at a different WiMAX cell. We use Markov processes to model the dynamics of the WiMAX traffic and WiFi traffic including the overflowed WiFi traffic, the vertical handoff WiFi traffic, the horizontal handoff WiFi traffic, and the take-back WiFi traffic. We derive various traffic arrival rates and performance metrics. Numerical results are provided for further quantitative evaluation.
technologies was investigated along with the related protocol issues for telemedicine services. In this paper, we consider an integrated wireless architecture using WiMAX as backhaul support for WiFi traffic. One unique feature is that the WiFi traffic in our model completely reflects the realistic user behavior. Previous study on the integrated architecture usually considers static or limited mobility for WiFi users, where WiFi users use WiMAX or cellular infrastructure as backhaul support only inside the WiFi cell via their AP and cannot utilize the infrastructure any more when they move out of the WiFi cell. In our scenario, a WiFi call may be overflowed to the overlaid WiMAX cell when no channel is available at the WiFi cell; the WiFi user may also work some period of time in the WiFi cell and then make a vertical handoff to its overlaid WiMAX cell when it needs to move from its current WiFi cell (e.g., office) to its target WiFi cell (e.g., airport). Further, the target WiFi cell may be located at another place in the same WiMAX cell, or at a different WiMAX cell. To the best of our knowledge, there has been no analytical modeling for these situations, which is focused on this paper. The remainder of the paper is organized as follows. Section II describes the integrated WiFi and WiMAX architecture. Section III provides the details of modeling and performance analysis for both WiFi cell and WiMAX cell as well as the derivation of various arrival rates and performance metrics. Section IV presents numerical results. Finally, the paper is concluded in Section V. II. SYSTEM DESCRIPTION