Wireless: Solution for high-speed Internet access in regional Queensland Presenter: Mr. Huan Pham...
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Transcript of Wireless: Solution for high-speed Internet access in regional Queensland Presenter: Mr. Huan Pham...
Wireless:Wireless: Solution for high-speed Internet access Solution for high-speed Internet access
in regional Queenslandin regional Queensland
Wireless:Wireless: Solution for high-speed Internet access Solution for high-speed Internet access
in regional Queenslandin regional Queensland
Presenter: Mr. Huan Pham (PhD student)
Supervised by Dr. Bill Lavery
James Cook University
Internet Access PlatformsInternet Access PlatformsInternet Access PlatformsInternet Access Platforms
Twisted pair
Coax/Fibre
Optical Fibre
Wireless
• Cable modem
•Tel modem•ISDN•xDSL
•FTTH•Fibre ring
•MMDS•LMDS
•Satellite
Internet
xDSL modem
xDSL modem
ISDN adapter
Telephone modem
Exchange
ISP
Twisted PairTwisted PairTwisted PairTwisted Pair
Twisted Pair CapacityTwisted Pair CapacityTwisted Pair CapacityTwisted Pair Capacity
Telephone modem < 64 Kbit/s (for download, lower for upload)
ISDN Basic 128 Kbit/s, (bi-directional)
xDSL Symmetrical or Asymmetrical Maximum download rate from 1.5 Mbit/s to 50 Mbit/s depending
on the technology and distance. Upload rate for asymmetrical case: dozens Kbit/s
Distance limit: < 5 km from CO or Remote access terminal Access capacity not shared by other users.
Coax/Fibre cableCoax/Fibre cableCoax/Fibre cableCoax/Fibre cable
Internet
Cable Modem
ISP
NIU
Fibre Node
Cable Modem
NIU
Fibre Node
Coaxial Cable
Optical Fibre
Coax/Fibre CapacityCoax/Fibre CapacityCoax/Fibre CapacityCoax/Fibre Capacity
Downstream up to 30 Mbit/s Upload up to 10 Mbit/s Bit rate is shared among subscribers passed by
coax cable. --> bit rate/user is lower
Wireline advantages/disadvantagesWireline advantages/disadvantagesWireline advantages/disadvantagesWireline advantages/disadvantages
Advantages Potentially offer very high bit rate More reliable (less affected by noise, interference,
weather conditions) Disadvantages
High up-front investment in cabling, environment issues, permission to lay cable...
Much higher cost per user in low population density areas
Higher deployment time Monopoly by cabling companies
Wireless OptionsWireless OptionsWireless OptionsWireless Options
MMDS (and other WLL operating at 2 - 5 MHz)
LMDS (Local Multipoint Distribution Services)
Satellite
Mobile
MMDSMMDSMMDSMMDS
Main transmitter
Repeater
Internet Point of Presence
MMDSMMDSMMDSMMDS
Frequency 2.1 GHz, 2.3 GHz (in Australia) Line of sight transmission Not vulnerable to rain Maximum coverage distance = 50 km Normally one way - telephone cable return Two-way MMDS is more costly and limited by available
bandwidth Bandwidth is shared among all (online) users Frequency reuse can be made by using n-sector antennas,
and/or cellular layout (the latter is subject to ACA regulation)
MMDS CapacityMMDS CapacityMMDS CapacityMMDS Capacity
Assumptions:MMDS Channel: 6MHz
Modulation scheme: QAM-64
Customer peak offered rate: 400 (Kbit/s)
Statistical multiplexing gain: 5
User time online: 20%
Capacity:Number of users (one sector):
Number of users (four sectors): 4 x 2000 = 8000
2000)/(400%20
5)/(30
sKbit
sMbit
30Mbit/s
Other Frequency OptionsOther Frequency OptionsOther Frequency OptionsOther Frequency Options
2 x 150 MHz frequency at 3.4 GHz band. (this is to
be auctioned later this year)
Unlicensed frequency band at 2.4 GHz and 5GHz
LMDSLMDSLMDSLMDS
Frequency: 28 GHz Strict line-of-sight transmission Signal absorbed by rain (See Signal in Rain graph) Cellular layout. Cell size (<5 km) mainly depends on:
transmitter power modulation scheme rain rate required availability
Frequency reuse made possible by n-sector antennas cellular layout cross-polarisation transmission
LMDS CapabilityLMDS CapabilityLMDS CapabilityLMDS Capability
AssumptionsBandwidth 2x75 (MHz)
Modulation scheme QAM-16
Frequency reuse factor/cell: 4
Cell size (square): 5(km) x 5(km)
CapacityBit rate / cell: 400 (Mbit/s)(able to support about 1000s online users, peak rate a couple of Mbit/s)
Bit rate / km2: 16 Mbit/s/km2
~100 Mbit/s each way
LMDS Hexagon layoutLMDS Hexagon layoutLMDS Hexagon layoutLMDS Hexagon layout
Frequency reusefactor = 4
Frequency reusefactor = 3
LMDS Square LayoutLMDS Square LayoutLMDS Square LayoutLMDS Square Layout
Frequency reusefactor = 1
Frequency reusefactor = 2
Frequency reusefactor = 4
SatelliteSatelliteSatelliteSatellite
Web server
Internet
Satellite
ISP
Satellite CapabilitySatellite CapabilitySatellite CapabilitySatellite Capability
Satellite operates at C-band (4-8GHz) or Ku-band (12-
18GHz) which is affected by weather condition.
Large coverage areas, virtually anywhere.
It’s difficult to apply frequency reuse. Thus it offers limited
bit rate/user.
Commonly available with one-way Internet access, return
via telephone modem. Typically 400Kbit/s download
Suits non real-time applications
Suitable for areas where other options are not available
SummarySummarySummarySummary Advantages of Wireless over Wireline
Scalability Lower up-front investment Fast deployment time Ability to bypass the incumbent Telco.
Limitations Limited bandwidth Affected by noise, interference, weather conditions Latency of satellite systems limit real-time applications
The advantages make them suitable for low density population areas in regional Queensland such as Townsville & Carne.
Current ResearchCurrent ResearchCurrent ResearchCurrent Research
Performance of TCP over wireless and...
How to facilitate QoS (Quality of Service) over
wireless link
Questions?Questions?Questions?Questions?
Thank you!Thank you!
The EndThe End
Thank you!Thank you!
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