Post on 18-Jan-2018
description
Heterogeneous Wireless Access in Large Mesh Networks
Haiping Liu, Xin Liu, Chen-Nee Chuah, Prasant MohapatraUniversity of California, Davis
IEEE MASS 2008
Outline
Introduction Related Work Theoretical Study Proposed Method Evaluation Conclusion
Introduction
The Major obstacles of large Wi-Fi mesh network Multihop transmission
The performance of multihop transmission decreases quickly as the number of hops increases
Link quality Depending on specific topologies and failure probabilities, the
proportion of island nodes may not be negligible. Distributed
In large mesh networks, centralized MAC-layer schemes, global link transmission scheduling, or synchronization are not practical.
Introduction
The Major obstacles of large WiMAX mesh network Spatial-reuse
Although the large cover age of WiMAX reduces the number of wireless hops in the network, it cannot support good spatial-reuse of spectrum.
Expensive WiMAX devices have much higher power consumption and are much m
ore expensive than Wi-Fi devices. Deployment
Wi-Fi devices have been widely deployed, and there fore it is beneficial to integrate WiMAX networks with existing Wi-Fi network.
Architecture
Customer terminal
mesh node
WiMAX base station(WMBS)
portal
Related Work
WiMAX-only mesh network Cannot fully reuse bandwidth and disregards the widel
y deployed Wi-Fi device
Wi-Fi/WiMAX Few of them analyze the major drawbacks of Wi-Fi or
WiMAX-only mesh networks, offer theoretical proof of the heterogeneous architecture and publish corresponding solution.
Goal
The paper propose an integrated Wi-Fi / WiMAX architecture that exploits the advantages of both technologies.
The primary objective of this paper is to facilitate a good cooperation of the last two kinds of connections and improve the overall system performance
Theoretical Study – Notation
γ Maximum utilization in the heterogeneous network
Theoretical Study – Formulation
Theoretical Study – Environment Set
Environment Set
Node equips with both Wi-Fi and WiMAX devices
Link CapacityWi-Fi 54Mbps
WiMAX 70Mbps
CoverageWi-Fi between any two neighboring Wi-Fi nodes
WiMAX whole network
Theoretical Study – Solution and Analysis
Protocol Design
Although it is shown that a heterogeneous network is a good solution through the theoretical study, it is necessary to design a protocol that can achieve the gain in practice and deal with challenges that are not captured by the idealized model.
We propose a threshold-based protocol and an optimization algorithm
Assumptions
WiMAX utilized the scheduled MAC scheme.
In Wi-Fi networks, nodes utilize IEEE 802.11 MAC instead of the scheduled MAC as in theoretical study.
The WMBSs do not try to control the routing or scheduling inside the Wi-Fi network.
Proposed Protocol – LABHW
TH = 10
Conga = 5 < 10 = TH
WMBSNode a
Conga = 15 > 10 = THRequest
Collect Requests from all nodes and run the algorithm.
Reject Accept/
Traffic = 15Receive and forward TrafficReclaim BW
Update and Broadcast TH
LABHW Algorithm – Notification
LABHW Algorithm – Formulation
WMBS
Node i Node j
Evaluation – Environment Set
Environment Set
node equip with both Wi-Fi and WiMAX devices
link capacityWi-Fi 54Mbps
WiMAX 70Mbps
coverageWi-Fi between any two neighboring Wi-Fi nodes
WiMAX whole network
Simulator Qualnet 4.0
Evaluation
Evaluation
Evaluation
Evaluation
Evaluation
Conclusion
This paper proposes a heterogeneous network architecture, consisting of Wi-Fi and WiMAX.
To solve the major problems and improve the performance of multihop Wi-Fi mesh networks of large size.
Based on the insights from the theoretical study, we design a practical protocol.
Thank You