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Saint Petersburg State University of Telecommunications. Providing of QoS in prospective Wi-Fi networks. 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.
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Saint Petersburg State University of Telecommunications Providing of QoS in prospective Wi-Fi networks 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 Use of wireless networks Museums Hospitals Conferences
Hotspots Airports Hotels Cafes
Russianoperators Source: J'son & Partners
Top Russian Wi-Fi providers 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 Sources: Company Data, J'son & Partners
Number of hotspots Source: J'son & Partners
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%.
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 STA3 ESS BSS2 STA2
Ad hoc network STA1 STA2 BSS1 STA3 STA5 STA4 BSS2
Frequency Hopping Spread Spectrum - FHSS different frequency hopping schemes Direct Sequence Spread Spectrum - DSSS spread by Barker code
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
A Wi-Fi network model Access Point Station 1 MPEG-4 Stations downloading files from the Internet
Superframe Contention period (CP) Contention free period (CFP) t TXOP STA1 ACK frames CF - End Beacon Station 1 (MPEG-4) Beacon Data Frames Other stations (Internet data)
Contention free period (CFP) STA2STA3 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)
Contention free period (CFP) STA2 STA3 t TXOP STA1 Contention free period (CFP) Contention free period (CFP) STA2 STA3 STA4 STA5 t TXOP STA1 Station 1 (MPEG-4) Other stations (data)
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