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Saint Petersburg State University of Telecommunications
Roman V. Plyaskin [email protected]
Advisor: Prof. Alexander E. Ryzhkov
Outline
Review of Wi-Fi networks
IEEE 802.11 standard
QoS in Wi-Fi networks
A Wi-Fi network model
Museums Hospitals Conferences
Review of Wi-Fi networks
Hotspots
Airports
Hotels Cafes
Russian operatorsAeroport Peter-star
Aist Polyarnaya Zvezda
ArtCommunications Quantum
Avantel Rambler Telecom
CityNet Rinet
Comstar United Telesystems RISS Telecom
Equant RTComm-Yug
eWi-Fi Samara Internet
Golden Telecom South Telecommunications Company
Infotecs Taganrog Telecom Stelcom
MegaFon Tascom
Moscom Vimpelcom
MTS Wi-Finder
MTU-Intel** Wiland
Netprovodov.ru Zebra Telecom Source: J'son & Partners
Top Russian Wi-Fi providers
Rank Company City Hotspots
1. Tascom Moscow 40
2. Quantum St. Petersburg 22
3. Moscom Moscow 20
4. Stelcom Moscow 17
5. Golden Telecom
Moscow 15
6. Peterstar St. Petersburg 11
7. EWi-Fi Moscow 10
Source: J'son & Partners
Two models of Wi-Fi services providing
Commercial Noncommercial
3-15 $ per hour or MB of the traffic
Cost of one-time installation and monthly subscription fees
Top Wi-Fi providers by commercial and free-of-charge locations
Rank Company City CommercialFree-of-charge *
Test
1. Tascom Moscow 11 29 21
2. Quantum St. Petersburg 22 - n/a
3. Moscom Moscow 20 - 15
4. Stelcom Moscow 17 - 9
5. Golden Telecom
Moscow 10 5 6
6. Peterstar St. Petersburg 11 - 5
7. EWi-Fi Moscow 10 - n/a
Sources: Company Data, J'son & Partners
World
Commercial 90%
Noncommercial10%
Russia
Commercial 67%
Noncommercial33% Source: J'son & Partners
0
10
20
30
40
50
60
70
80
90
Moscow St.Petersburg
Commercial
Noncommercial
Number of hotspots
Source: J'son & Partners
Hotspots by type of location
Restaurant/CafeHotelAirportOther
Source: J'son & Partners
0,00%
20,00%
40,00%
60,00%
80,00%
100,00%
120,00%
Restaurant/Cafe Hotel Other
Noncommercial
Commercial
Share of noncommercial hotspots
Source: J'son & Partners
According to J’son & Partners, there will be 1250 – 1500 commercial hotspots and 25-30 thousands Wi-Fi users by the end of 2008
According to BroadGroup agency, which has analyzed the fees of 122 operators in 28 countries, the average European fee is € 5,74 per hour (without taxes). Since the beginning of 2004 it has been decreased in 11%.
The scope of the standard 802.11 is to develop a medium access control and physical layer specifications for providing quick wireless connectivity between portable and moving stations within a local area.
IEEE 802.11 standard
BSS1
BSS2
STA1
AP
APSTA3
STA2
infrastructure network DS
ESS
BSS1
BSS2
STA1STA2
STA3
STA4STA5
Ad hoc network
Frequency Hopping Spread Spectrum - FHSS
different frequency hopping schemes
Direct Sequence Spread Spectrum - DSSS
spread by Barker code
802.11b wireless networks
Data rate, Mbps
Code sequence Modulation
1 11 chips (Barker code) DBPSK
2 11 chips (Barker code) DQPSK
5,5 8 chips (СCK) DQPSK
11 8 chips (СCK) DQPSK
802.11g wireless networks
Data rates, Mbps Modulation
Obligatory Optional
1 Barker code
2 Barker code
5,5 CCK РВСС
6 ERP-OFDM DSSS-OFDM
9 ERP-OFDM, DSSS-OFDM
11 CCK РВСС
12 ERP-OFDM DSSS-OFDM
18 ERP-OFDM, DSSS-OFDM
22 РВСС
24 ERP-OFDM DSSS-OFDM
33 РВСС
36 ERP-OFDM, DSSS-OFDM
48 ERP-OFDM, DSSS-OFDM
54 ERP-OFDM, DSSS-OFDM
• voice over Internet Protocol (VoIP)• video streaming• music streaming• interactive gaming
Quality of Service in Wi-Fi networks
QoS allows network owners to leverage the Wi-Fi infrastructure to offer a richer set of services.
• Wi-Fi home networking is spreading rapidly among households
• Residential broadband penetration has taken off
• New services, digital content, and new applications are becoming more widely available
• A wide range of products addressing digital entertainment connectivity are rapidly entering the market
Demand for Wi-Fi multimedia applications is growing rapidly due to:
Enterprise market • cost savings • prioritized traffic management
Public marketUsers are increasingly accustomed to VoIP and multimedia applications.
Residential market • a wider array of Wi-Fi-enabled devices• providing wireless voice connectivity • using the Wi-Fi network to distribute content
from a media server• establishing wireless connectivity between
devices• supporting peer-to-peer networks for
telephony or gaming
Access Category
Description 802.1D tags
Voice Highest priority. Allows multiple concurrent VoIP calls, with low latency and toll voice
quality
7, 6
Video Prioritize video traffic above other data traffic. One 802.11g or 802.11 a channel can support 3-4 SDTV streams or 1 HDTV
streams
5, 4
Best Effort Traffic from legacy devices, or traffic from applications or devices that lack QoS capabilities. Traffic less sensitive to
latency, but affected by long delays, such as Internet surfing
0, 3
Background Low priority traffic (file downloads, print jobs) that does not have strict latency and
throughput requirements
2, 1
Access categories
A Wi-Fi network modelAccess Point
Station 1MPEG-4
Stations downloading files from the Internet
Superframe
Contention free period (CFP)
Contention period (CP)
Beacon
TXOP STA1
ACK frames Beacon
CF - End
Data Frames
Station 1 (MPEG-4)
Other stations (Internet data)
t
Contention free period (CFP)
TXOP STA1
Station 1 (MPEG-4)
Other stations (data)
Contention free period (CFP)
TXOP STA1
STA2 STA3 STA4 STA5 STA6
STA2 STA3 STA4 STA5 STA6 STA7 STA8
t
t
Scenario 1. Throughput
0
100
200
300
400
500
600
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Thro
ughp
ut,
kbps
Superframe = 5 ms
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 1. Delays
Station 1 (MPEG-4)
Other stations (data)
Contention free period (CFP)
TXOP STA1
STA2 STA3 STA4 STA5
t
TXOP STA1
STA2 STA3
t
Contention free period (CFP)
Contention free period (CFP)
0
100
200
300
400
500
600
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Thro
ughp
ut,
kbps
Superframe = 5 ms
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 2. Throughput
0
50
100
150
200
250
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Number of stations
Del
ay, m
s
Superframe = 5 ms
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 2. Delays
0
100
200
300
400
500
600
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Th
rou
gh
pu
t, k
bp
s
Superframe = 5 ms
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 3. Throughput
0
50
100
150
200
250
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Del
ay, m
s
Superframe = 5 ms
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 3. Delays
Scenario 4. Throughput
Scenario 4. Delay
0
100
200
300
400
500
600
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Th
rou
gh
pu
t, k
bp
s
Probability = 5%
Probability = 10%
Probability = 20%
Scenario 4. Throughput
0
10
20
30
40
50
60
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Del
ay, m
s
Probability 5%
Probability 10%
Probability 20%
Scenario 4. Delays
0
100
200
300
400
500
600
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Th
rou
gh
pu
t, k
bp
s
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 5. Throughput
0
50
100
150
200
250
300
350
400
450
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Del
ay, m
s
Superframe = 10 ms
Superframe = 15 ms
Superframe = 20 ms
Superframe = 50 ms
Superframe = 100 ms
Scenario 5. Delays
Conclusion
• Tendency of Wi-Fi networks spreading in Russia• Importance of QoS implementation in Wi-Fi networks• simulation of a typical Wi-Fi network model • Analysis of the throughput and delays in different transmission scenarios• Realization of QoS requirements needs adaptive software for access points
Thank you!