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

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 (W 2 -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 W 2 -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 a OFDM PHY or to decapsulate a single WiFi PDU into its WiMAX PDU.

MAC Module in W 2 -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 W 2 -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 SS-MAC functions WiMAX BS the MAC layer is the same as that defined in the IEEE standard

Two-Level Hierarchical Bandwidth Allocation (THBA) W 2 -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 Traffic TypeCBR (kbps)Interval (ms) VoIP (UGS)6420 Video (rtPS)12810 Web (BE) Total Bandwidth64MbpsTDD DL/UL Ratio1:1

three specific bandwidth allocation protocols THBA scheme Each W 2 -AP aggregates all the bandwidth demands with the same QoS level received from its WiFi nodes Independent bandwidth allocation control The W 2 -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 e 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 W 2 -AP and modify 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