Transcript Document

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
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Introduction
Description of Network Model
Bandwidth Allocation and Management
Performance Evaluation
Conclusions
Introduction
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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
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a single WiMAX BS, operating in a licensed band,
serves both multiple WiMAX Subscriber Stations
(SSs) and multiple W2-APs
Proposed MAC Layer Module
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MultiMAC
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dynamic switching between different MAC protocols
ex: adding a byte to the header of the frame for identification
purposes
SoftMAC
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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
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UL Aggregator/Classfier
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Packet Classification
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temporarily buffer the UL data
packets based on their
corresponding priority
BW-REQ Aggregation
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aggregate all bandwidth demands at
the same QoS level from WiFi
nodes into a single bandwidth
request
MAC Module in W2-AP Device
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The UL and DL
bandwidth information is
passed down to the
DL/UL-MAP Generator
MAC Module in WiFi Node/WiMAX BS
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WiFi Node
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modified by adding MultiMAC, SoftMAC and
802.16 SS-MAC functions
WiMAX BS
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the MAC layer is the same as that defined in the
IEEE 802.16 standard
Two-Level Hierarchical
Bandwidth Allocation (THBA)
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W2-AP attempts to aggregate bandwidth
demands having the same level of QoS
Frame Operation in Level A/B
Second-Hop Frame Gap
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WiFi and WiMAX networks use different
frequency bands, and thus the problem of
interference is neglected
Simulation Model
Total Bandwidth
DL/UL Ratio
64Mbps
1:1
TDD
Traffic Type
CBR (kbps)
Interval (ms)
VoIP (UGS)
64
20
Video (rtPS)
128
10
Web (BE)
64
12.5
three specific bandwidth
allocation protocols
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THBA scheme
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Independent bandwidth allocation control
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Each W2-AP aggregates all the bandwidth demands
with the same QoS level received from its WiFi nodes
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
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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
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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-toend delays of high priority traffic
Comment
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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