Saint Petersburg State University of Telecommunications
Roman V. Plyaskin
romick2000@yandex.ru
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
Review of Wi-Fi networks
Museums
Hospitals
Conferences
Hotspots
Airports
Hotels
Cafes
Russian operators
Aeroport
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
1.
2.
3.
4.
5.
6.
7.
Company
Tascom
Quantum
Moscom
Stelcom
Golden
Telecom
Peterstar
EWi-Fi
City
Moscow
St. Petersburg
Moscow
Moscow
Moscow
Hotspots
40
22
20
17
15
St. Petersburg
Moscow
11
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
Commercial
Free-ofcharge *
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%
Noncommercial
10%
Russia
Commercial 67%
Noncommercial
33% Source: J'son & Partners
Number of hotspots
90
80
70
60
50
Commercial
40
Noncommercial
30
20
10
0
Moscow
St.Petersburg
Source: J'son & Partners
Hotspots by type of location
Restaurant/Cafe
Hotel
Airport
Other
Source: J'son & Partners
Share of noncommercial hotspots
120,00%
100,00%
80,00%
Noncommercial
60,00%
Commercial
40,00%
20,00%
0,00%
Restaurant/Cafe
Hotel
Other
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%.
IEEE 802.11 standard
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.
infrastructure
network
AP
STA1
DS
BSS1
AP
ESS
STA3
STA2
BSS2
Ad hoc network
STA1
STA2
BSS1
STA3
STA4
STA5
BSS2
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
Quality of Service in Wi-Fi networks
•
•
•
•
voice over Internet Protocol (VoIP)
video streaming
music streaming
interactive gaming
QoS allows network owners to leverage the Wi-Fi
infrastructure to offer a richer set of services.
Demand for Wi-Fi multimedia applications is growing rapidly
due to:
• 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
Enterprise market
• cost savings
• prioritized traffic management
Public market
Users 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 categories
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
Background
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
Low priority traffic (file downloads, print jobs) that
does not have strict latency and throughput
requirements
0, 3
2, 1
A Wi-Fi network model
Access Point
Station 1
MPEG-4
Stations downloading files from
the Internet
Superframe
Contention free period (CFP)
Contention
period (CP)
t
TXOP STA1
ACK frames
Beacon
Data
Frames
CF - End
Beacon
Station 1 (MPEG-4)
Other stations
(Internet data)
Contention free period (CFP)
STA2
STA3
STA4
STA5
STA6
t
TXOP STA1
Contention free period (CFP)
STA2
STA3
STA4
STA5
STA6
STA7
STA8
t
TXOP STA1
Station 1 (MPEG-4)
Other stations (data)
Scenario 1. Throughput
Throughput, kbps
600
Superframe = 5 ms
500
Superframe = 10 ms
400
Superframe = 15 ms
300
Superframe = 20 ms
200
Superframe = 50 ms
100
Superframe = 100 ms
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Scenario 1. Delays
Contention free period (CFP)
STA2
STA3
t
TXOP STA1
Contention free period (CFP)
STA2
STA3
Contention free period (CFP)
STA4
STA5
t
TXOP STA1
Station 1 (MPEG-4)
Other stations (data)
Scenario 2. Throughput
Throughput, kbps
600
Superframe = 5 ms
500
Superframe = 10 ms
400
Superframe = 15 ms
300
Superframe = 20 ms
200
Superframe = 50 ms
100
0
Superframe = 100 ms
1
4
7
10 13 16 19 22 25 28 31 34 37 40
Number of stations
Scenario 2. Delays
250
Superframe = 5 ms
Delay, ms
200
Superframe = 10 ms
150
Superframe = 15 ms
100
Superframe = 20 ms
Superframe = 50 ms
50
Superframe = 100 ms
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Number of stations
Scenario 3. Throughput
Throughput, kbps
600
500
Superframe = 5 ms
400
Superframe = 10 ms
Superframe = 15 ms
300
Superframe = 20 ms
200
Superframe = 50 ms
100
Superframe = 100 ms
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Delay, ms
Scenario 3. Delays
250
Superframe = 5 ms
200
Superframe = 10 ms
150
Superframe = 15 ms
100
Superframe = 20 ms
50
Superframe = 50 ms
0
Superframe = 100 ms
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Scenario 4. Throughput
Scenario 4. Delay
Scenario 4. Throughput
600
Throughput, kbps
500
400
Probability = 5%
300
Probability = 10%
Probability = 20%
200
100
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Scenario 4. Delays
60
Delay, ms
50
40
Probability 5%
30
Probability 10%
20
Probability 20%
10
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Scenario 5. Throughput
600
Throughput, kbps
Superframe = 10 ms
500
400
Superframe = 15 ms
300
Superframe = 20 ms
200
Superframe = 50 ms
100
Superframe = 100 ms
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
Scenario 5. Delays
450
Superframe = 10 ms
400
Delay, ms
350
Superframe = 15 ms
300
250
Superframe = 20 ms
200
150
Superframe = 50 ms
100
50
0
Superframe = 100 ms
1
4
7 10 13 16 19 22 25 28 31 34 37 40
Number of stations
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!