providing of qos in prospective wi-fi networks

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

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!