An Integrated WiMAX/WiFi Architecture with QoS Consistency over Broadband Wireless Networks

An Integrated WiMAX/WiFi Architecture with QoS Consistency over Broadband Wireless Networks Hui-Tang Lin, Ying-You Lin, Wang-Rong Chang, and Rung-Shiang Cheng IEEE Consumer Communications and Networking Conference 2009 報告者 : 李宗穎

Outline • Introduction • Description of Network Model • Bandwidth Allocation and Management • Performance Evaluation • Conclusions

Introduction • WiMAX and WiFi have emerged as promising broadband access solutions for the latest generation of wireless MANs and LANs • an integrated architecture utilizing a novel WiMAX/WiFi Access Point (W2-AP) device to effectively combine the WiMAX and WiFi technologies

Integrated WiMAX/Wifi System • a single WiMAX BS, operating in a licensed band, serves both multiple WiMAX Subscriber Stations (SSs) and multiple W2-APs

Proposed MAC Layer Module • MultiMAC • dynamic switching between different MAC protocols ex: adding a byte to the header of the frame for identification purposes • SoftMAC • encapsulate a WiMAX PDU into a single WiFi PDU over 802.11a OFDM PHY or to decapsulate a single WiFi PDU into its WiMAX PDU.

MAC Module in W2-AP Device • UL Aggregator/Classfier • Packet Classification • temporarily buffer the UL data packets based on their corresponding priority • BW-REQ Aggregation • aggregate all bandwidth demands at the same QoS level from WiFi nodes into a single bandwidth request

MAC Module in W2-AP Device • The UL and DL bandwidth information is passed down to the DL/UL-MAP Generator

MAC Module in WiFi Node/WiMAX BS • WiFi Node • modified by adding MultiMAC, SoftMAC and 802.16 SS-MAC functions • WiMAX BS • the MAC layer is the same as that defined in the IEEE 802.16 standard

Two-Level Hierarchical Bandwidth Allocation (THBA) • W2-AP attempts to aggregate bandwidth demands having the same level of QoS

Frame Operation in Level A/B • WiFi and WiMAX networks use different frequency bands, and thus the problem of interference is neglected Second-Hop Frame Gap

Simulation Model

three specific bandwidth allocation protocols • THBA scheme • Each W2-AP aggregates all the bandwidth demands with the same QoS level received from its WiFi nodes • Independent bandwidth allocation control • The W2-AP directly allocates its own bandwidth to its WiFi nodes based on their bandwidth requirements and buffers the packets sent from the WiFi nodes • WiMAX with EDCA control • IEEE 802.11e NIC card to employ a priority-based EDCA bandwidth contention protocol for accessing the channel

Mean end-to-end delay of various traffic classes for various network offered loads

Mean end-to-end delay of various traffic classes for the number of VoIP connections within the network

Mean end-to-end delay versus number of WiFi nodes per WiFi hotspot

Conclusion • By using the W2-AP and modify 802.11 NIC card, the integrated architecture enables the use of a common protocol operation between the WiMAX and WiFi components of the network • THBA mechanism can reduces the end-to-end delays of high priority traffic

Comment • 英文寫的很難懂 • 沒有較詳細的頻寬分配方法 • 雖然只要軟體升級，但要修改到WiFi節點會比較造成支援度便利性不足

An Integrated WiMAX/WiFi Architecture with QoS Consistency over Broadband Wireless Networks