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 (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 purp

oses 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

Traffic Type CBR (kbps) Interval (ms)

VoIP (UGS) 64 20

Video (rtPS) 128 10

Web (BE) 64 12.5

Total Bandwidth 64Mbps TDD

DL/UL Ratio 1:1

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 ED

CA 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