Merges of Wireless Communications and Computer Networks

1
Merges ofWireless CommunicationsandComputer
Networks

• George Lee

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Abstract (1)

• Merge ATM technology inWireless Communications
  Network
• ATM Wireless Network(ATM as wireless networks
  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 ?)

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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,...

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Introductions

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

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Evolution of mobile multimedia services
(Nakamura et. Al)
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• 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 gt client)
• WWW, VOD,
• Point-to-Multi-point
• VOD
• The need for mobile communicationsin LAN/ATM
• Portability Networking

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Merges of Wireless Communications and Computer
Networks (3rd gen.)
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Merges of Wireless Communications and Computer
Networks (4th gen.)
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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.

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

• Power efficiency? Voice-Operated Transmission
  (VOX) BS ? MSC? STM ? ATM

Nakamura et. al
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• QoS? Diversity Handoff MS ? BS ? BSC ? STM ?
  ATM

Nakamura et. al
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• To reduce ATM Packetization delay? Layered cell
  Multiplexing in BS ? BSC

Multiplexing
CPSCommon part sublayer
Nakamura et. al
Nakamura et. al
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Wireless LAN

• 2 types of networks
• Defined in
• Physical layer
• Media Access Control layer

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(1) Ad hoc network
802.11
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(2) Infrastructure network
ESS Extended Service Set
802.3, 802.4,802.5, 802.6,or FDDI Backbone
802.11
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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

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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.

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ETSI HIPPERLAN ad hoc network
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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

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Wireless ATM Architecture
AP
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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

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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

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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)

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Conclusion (3)

• QoS
• Voice
• CBR/AAL 1
• IP datagram
• UBRABR/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