Interference-Aware IEEE 802.16 WiMax Mesh Networks

1
Interference-Aware IEEE 802.16 WiMax Mesh
Networks
Vehicular Technology Conference, 2005. VTC
2005-Spring. 2005 IEEE 61stPublication Date 30
May-1 June 2005

• Hung-Yu Wei, Samrat Ganguly, Rauf Izmailov
• Broadband Mobile Networking Department
• NEC Laboratories America
• Princeton, New Jersey, USA

Zygmunt J. Haas School of Electrical and
Computer Engineering Cornell University Ithaca,
New York, USA

Presented by Chan Chih-Yuan
2
Outline

• Section 1. Introduction
• Section 2. Overview Of Wimax Mesh Mode
• Section 3. Interference-Aware Design With 802.16
  Mesh
• Section 4. Performance Evaluation
• Section 5. Conclusion

3
Introduction

• IEEE 802.16 standard
• high speed at low cost, and easy to deploy.
• great wireless coverage of about 5 miles with LOS
  (line of sight) transmission within bandwidth of
  up to 70 Mbps.
• Wide-area wireless backhaul network
• Increase the wireless coverage
• Provides features such as lower backhaul
  deployment cost, rapid deployment, and
  reconfigurability.

4

• Cross-layer design and optimization
• Application Layer Load Demand
• Physical Layer Interference Information
• Scheduling and Route Selection Mechanism in Data
  Link Layer
• Interference-Aware IEEE 802.16 Framework
• Interference-aware route construction algorithms
• Enhanced centralized mesh scheduling scheme
• Lead to better spatial reuse and higher spectral
  efficiency.

5
Motivation Problem Overview

• Comparison with 802.11a/b/g mesh network
• Advantage from increased range and higher
  bandwidth.
• Provide fine granularity radio resource control.
• TDMA-based scheduling mechanism allows
  centralized slot allocation.
• Interference remains a major issue in multi-hop
  Wimax mesh networks.
• To Provide high spectral usage, an efficient
  algorithm for slot allocation is needed, so as to
  maximized the concurrent transmission of data in
  the mesh.

6
Mesh Mode Acronyms
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IEEE Mode Operation

• Entry process
• MSH-NCFG(Mesh Network Configuration)
• MSH-NENT(Mesh Network Entry)
• Request and granting procedure
• MSH-CSCH(Mesh Centralized Scheduling)
• MSH-CSCHRequest
• MSH-CSCHGrant
• MSH-CSCF(Mesh Centralized Scheduling
  Configuration)

8
Interference-Aware Route Construction
Algorithms(1)

• To achieve efficient spectral utilization and
  high throughput in 802.16 mesh networks, the
  route construction within the mesh network is
  crucial.
• blocking value b(n)
• number of blocked nodes when node n is
  transmitting
• blocking metrics B(k) of a multihop route
• A given route from the Mesh BS toward an SS node
  k is introduced to model the interference level
  of routes in the mesh.
• Indicates number of blocked nodes by all
  intermediate nodes along the route from root node
  toward the destination node k..

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Interference-Aware Route Construction
Algorithms(2)
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Interference-Aware Route Construction
Algorithms(3)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
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s
s
Figure.1
Blocked Node
n1
b(2)4
b(1)2
d
d
s
s
b(3)3
B(1)4
n2
n3
d
d
12
s
s
Figure.2
n1
b(2)4
b(1)2
d
d
s
s
b(3)5
b(4)4
n2
n3
d
d
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Interference-Aware Scheduling Algorithms(1)

• To exploit concurrent transmission opportunity to
  achieve high spectral utilization and hence high
  system throughput.
• Seeks to maximize the number of concurrent
  transmissions without creating exceeding
  interference for other simultaneous transmission.
• Achieved by taking into the consideration the
  traffic capacity request of each SS node k from
  Mesh BS as D(k).

14
Interference-Aware Scheduling Algorithms(2)
15
Interference-Aware Scheduling Algorithms(3)
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Performance Evaluation

• Optimal Solution From Linear Program
• formulated to model the network throughput upper
  bound of IEEE 802.16 network.
• Throughput Performance in Chain Topology
• Route construction is straightforward.
• Throughput Performance in Random Topology
• Locations and a set of mesh nodes are randomly
  generated.

17
Optimal Solution From Linear Program
18
Optimal Solution From Linear Program
19
Optimal Solution From Linear Program

• Since the optimal linear programming algorithm is
  computed based on arbitrarily slicing of time
  fractions of all feasible transmission
  combinations, the performance of the
  discrete-time event driven design of proposed
  schemes is capped by the performance of the
  linear programming algorithm.

20
Overall throughput of a chain topology 802.16
network
Figure 6
21
Throughput Performance of random topology 802.16
mesh
Figure 7
22
Conclusion

• Allowing concurrent transmissions to achieve high
  spatial reuse is essential for scalable wireless
  mesh network.
• An interference-aware route construction
  algorithm for mesh network initialization
  process.
• A load-aware and interference-aware scheduling
  algorithm.
• Effectively improve the network throughput
  performance in IEEE802.16 mesh networks and
  achieve high spectral utilization.