Merges of Wireless Communications and Computer Networks

1. 1 Merges ofWireless CommunicationsandComputer Networks George Lee

2. 2 Abstract (1) • Merge ATM technology inWireless Communications Network • ATM Wireless Network(ATM as wireless network’s backbone) • Merge Wireless technology inLAN/ATM networks • Wireless LAN and Wireless ATM • WLAN: ETSI HIPERLAN (Ad hoc network) IEEE 802.11 (Infrastructure network) • WATM: ACTS (Lucent, NEC, Magic WAND) ATM Forum WATM WG (1999 ?)

3. 3 Abstract (2) • Issues in ATM Wireless Network • QoS  Voice-Operated Transmission (VOX) Diversity Handoff Layered Cell • Issues in Wireless LAN/ATM • Frequency allocation, Throughput, Mobility,Access Methods for Mobile Interface,Interference and Reliability, QoS,Mobile TCP/IP, TCP/IP over ATM, Security,Power Consumption, Human Safety,...

4. 4 Introductions • Evolution of wireless communications: • Evolution of computer networks: • LAN • Ethernet, Fast Ethernet, Gigabit Ethernet • FDDI • ATM • WAN • X.25 • Frame relay • ATM

5. 5 Evolution of mobile multimedia services (Nakamura et. Al)

6. 6 • The need for ATM in mobile infrastructure • Variable bit rate ( different traffic types) • Voice, FAX, video conference, ... • Wide range of bit rate ( different traffic types) • from low bit rate voice and data to high bit rate video • Asymmetrical communications ( server > client) • WWW, VOD, … • Point-to-Multi-point: • VOD • The need for mobile communicationsin LAN/ATM • Portability + Networking

7. 7 Merges of Wireless Communications and Computer Networks (3rd gen.)

8. 8 Merges of Wireless Communications and Computer Networks (4th gen.)

9. 9 References • H. Nakamura et. al, “Applying ATM to Mobile Infrastructure Networks,” IEEE Communications Magazine, Jan. 1998. • Pahlavan et. al, “Wideband Local Access: Wireless LAN and Wireless ATM,” IEEE Communications Magazine, Nov. 1997. • Crow et. Al, “IEEE 802.11 Wireless Local Area Networks,” IEEE Communications Magazine, Sep. 1997. • Passas et. al, “Quality-of-Service-Oriented Medium Access Control for Wireless ATM Networks,” IEEE Communications Magazine, Nov. 1997.

10. 10 4 Phases of ATM introduction to mobile networks 1 2A 2B 3 4 Nakamura et. al

11. 11 Requirements of ATM wireless infrastructure • Power efficiency Voice-Operated Transmission (VOX) BS  MSC STM  ATM Nakamura et. al

12. 12 • QoS Diversity Handoff: MS  BS  BSC  STM  ATM Nakamura et. al

13. 13 • To reduce ATM Packetization delay Layered cell: Multiplexing in BS  BSC Multiplexing CPS=Common part sublayer Nakamura et. al Nakamura et. al

14. 14 Wireless LAN • 2 types of networks: • Defined in • Physical layer • Media Access Control layer

15. 15 STA = Station BSS = Base Service Set (1) Ad hoc network 802.11

16. 16 STA = Station BSS = Base Service Set AP = Access Point (2) Infrastructure network ESS = Extended Service Set 802.3, 802.4,802.5, 802.6,or FDDI Backbone 802.11

17. 17 IEEE 802.11 • BSS & ESSSTA, AP, Portal (See Figure 1 & 2) • 2 types of traffics: • DCF = Distributed Coordination Function • CSMA/CA • Contention-based  Ad hoc/Infrastructure • PCF = Point Coordination Function • AP-controlled polling Infrastructure

18. 18 IEEE 802.11 (cont.) • 3 types of PHY layers: • FHSS (Frequency Hopping Spread Spectrum) • DSSS (Direct Sequence Spread Spectrum) • IR (infrared) • 2 modes in MAC • Contention mode: DCF only • Switching mode: switch between • Contention Period (CP): DCF • Contention Free Period (CFP): PCF • 3 kinds of MAC frames • Management, Control, Data.

19. 19 ETSI HIPPERLAN ad hoc network

20. 20 ETSI HIPPERLAN ad hoc network • Multi-hop ad hoc • 2 types mobile stations: • Non-Forwarder: receives its own frames only • Forwarder: receives all frames and forward • Multi-hop routing protocol • Between Forwarders • MAC • Non-Preemptive Multiple Access (NPMA) • LBT (Listen Before Talk) • Asynchronous transportIsochronous transport

21. 21 Wireless ATM Architecture AP

22. 22 Wireless ATM architecture • ACTS (Advanced Communications Technologies and Services) (Lucent, NEC, Magic WAND)ATM Forum WATM WG (1999 ?) • Magic WAND (Wireless ATM Network Demonstrator) • 4 kinds of components • Mobile Terminals (MT), Access Points (AP), ATM Switches (SW), Control Station (CS). • MASCARA (Mobile Access Scheme Based on Contention and Reservation for ATM) • ATM layer  Radio PHY layer • TDMA: variable-length time frames &dynamically allocated fixed-length time slots • Mixed use of Contention, Reservation, & Polling

23. 23 Conclusion (1) • Frequency allocation • Possible Freq. Bands • 2.4 GHz ISM • 1.9 GHz U-PCS • 5 GHz U-NII • Bit rate improved by • smaller packet • higher freq. Band • new mod. tech. • Throughput • Current: 2-20 Mbps • Goal: Higher bit rate • Mobility • Handoff schemes • Rerouting schemes

24. 24 Conclusion (2) • Access Methods for Mobile Interface • Wireless Comm.: • TDMA • FDMA • CDMA • Wireless LAN/ATM: • TDMA • FDMA  ABR ? • CDMA  bit rate? • Interference and Reliability • Multi-path fading • ARQ or FEC(Automatic Repeat Request)(Forward Error Correction)

25. 25 Conclusion (3) • QoS • Voice: • CBR/AAL 1 • IP datagram: • UBR|ABR/AAL 5 •  BER? Handoff ? • Mobile TCP/IP • MS freely moves: • TCP connection ? • IP address ? • TCP/IP over ATM • IP over ATM ? • LAN Emulation? • IP Switching ? • Tag Switching ? • Multi-Protocol over ATM ? • Security • Encryption • Power Consumption • Human Safety