Performance Analysis of Decentralized RAN Radio Access Network Selection Schemes

1
Performance Analysis of Decentralized RAN (Radio
Access Network) Selection Schemes

• December 28th, 2004
• Yang, Sookhyun

2
Contents

• Introduction
• Previous Works
• RAN Selection Schemes
• Evaluation Method
• Performance Analysis
• Conclusion

3
Background

• Emerging various wireless access technologies
• 2G, 3G celluar, satellite, WiBro/WiMax (IEEE
  802.16), Wi-Fi (IEEE 802.11a/b/g), Bluetooth
  (IEEE 802.15)
• In the Fourth-generation (4G) wireless network
• Multiple broadband wireless access
• Seamless mobility across heterogeneous networks

WWAN large coverage, high cost
WLAN high speed, moderate cost
WPAN small area, low speed, low cost
(HPi)
4
Motivation

• RAN Discovery
• Discover available access networks
• Scan a wide range of frequencies
• Power management
• RAN selection
• Determine the optimal access network among
  available RANs
• Many selection parameters
• Users network preference
• Communication charge
• Available bandwidth
• Power dissipation

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Previous Works

• Centralized approaches
• A centralized server collects and monitors
  available RANs
• A centralized server manages a mobile hosts
  position (GPS)
• BAN (Basic Access Network)-based scheme
• WISE (Wise Interface Selection)
• Decentralized approaches
• A mobile host itself monitors available RANs
• PPM (Power and Performance Management)
• NAV (Network Allocation Vector)-based scheme

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Decentralized Approaches

• RAN discovery
• Periodically turns on NICs (Network Interface
  Card)
• Static or Dynamic period
• All NIC or a CAN (Candidate Access Network)
• RAN selection
• QoS guarantee
• Signal strength is increasing
• Minimum power consumption
• Select before a handoff occurs
• Handoff occurs when QoS does not guarantee

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How to discover available RANs

• Static/Dynamic period
• Static period ? networks coverage
• Dynamic period ?
• mobile hosts velocity ?signal strength
• CAN (Candidate Access Network)
• Pre-select the optimal RAN among available RAN as
  a CAN
• Periodically check that a selected CAN guarantees
  QoS

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How to select the optimal RAN
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Objective

• Evaluate the performance of the following RAN
  selection schemes
• Static period with a CAN
• Dynamic period with a CAN
• Static period without a CAN
• Dynamic period without a CAN
• Continuously active scheme
• Performance Metrics
• Achieved bandwidth
• Number of handovers
• Power consumption per seconds

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Evaluation Environments
BS
BS
AP
NS2s mobility generator
AP
BS
BS
AP
0Mbps Signal is bad!
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Configuration

• Mobile node
• 100 nodes, maximum 11m/s (? 40km/h)
• Equipped with all types of network interfaces
• Network characteristics

Coverage (Km)
Bandwidth (Mbps)
Type
Power Consumption
Transmit (J/Mbits)
Idle (W)
Receive (J/Mbits)
Off (W)
ON (W)
2.5
2.4
CDMA1X
1.169
0.082
0.206
-
-
1
5
802.16
(0.264)
(0.2)
(0.13)
-
-
0.4
54
802.11a
0.022
1
0.035
-
-
0.4
11
802.11b
0.205
0.75
0.123
1.7(1ms)
2.3(0.3s)
0.4
54
802.11g
0.037
0.75
0.026
-
-
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Network Topologies

• Insufficient network resource

(b) Sufficient network resource
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Achieved bandwidth
Performance Analysis (1/3)

• Insufficient network resource

(b) Sufficient network resource
14
Number of handovers
Performance Analysis (2/3)
QoS degradation

• Insufficient network resource

(b) Sufficient network resource
15
Power consumption per Sec
Performance Analysis (3/3)
4.5 40 of a continuously active

• Insufficient network resource

(b) Sufficient network resource
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Observations and Analysis

• Four selection schemes show the same achieved
  bandwidth
• Dynamic or a CAN give large energy-saving
• But, when bandwidth is sufficient
• Static/dynamic with a CAN trigger too many
  handovers
• But, when bandwidth is not sufficient
• Static with a CAN consumes more power than
  Dynamic without a CAN

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Conclusion

• Evaluated decentralized approaches for RAN
  selection
• Implemented a simulator for wireless overlay
  network environment
• Dynamic with a CAN reduces large amount of power
  consumption without degrading achieved bandwidth
• But, too many handovers occur when bandwidth is
  sufficient

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Network Topologies

• Insufficient network resource

(b) Sufficient network resource
CDMA1X (4)
CDMA1X (4)
802.11g (10)
802.11g (26)
802.16 (20)
802.16 (10)
96
65
802.11a (10)
802.11b (31)
802.11a (21)
802.11b (25)