IEEE 802'15'3: Highrate WPAN Overview

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IEEE 802.15.3High-rate WPAN Overview
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Outline

• IEEE 802.15 Family
• Requirements of IEEE 802.15.3
• Layer Model
• IEEE 802.15.3 Standards
• Network Topology
• Network Operations
• Frame Architecture
• QoS Security

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IEEE 802.15 Family

• Wireless Personal Area Networks (WPAN)
• Communication within a persons operating space
  (10m)
• Short range / Low power / Low cost / Small
  networks
• IEEE 802.15 family
• IEEE 802.15.1 (Bluetooth)
• IEEE 802.15.3 (WiMedia)
• IEEE 802.15.4 (ZigBee)
• IEEE 802.15.2 defines the coexistence of WPAN
  with other wireless devices operating in
  unlicensed frequency bands

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Requirements of IEEE 802.15.3

• Main applications
• Personal area multimedia audio, video
• Wireless data transfer between consumer
  multimedia devices
• Requirements
• High data rate
• Low power consumption
• Low cost
• Fast configuration
• QoS support
• Security
• Ad-hoc topology

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Layer model
TCP/IP
IEEE 802.2 Logical Link Control (LLC)
Wireless FireWire
Wireless USB
802.2 FCSL (mandatory)
IEEE 1394 FCSL (optional)
USB FCSL (optional)
802.15.3 Medium Access Control (MAC)
IEEE 802.15.3
802.15.3 PHY 11, 22, 33, 44, 55 Mbit/s
802.15.3a PHY Ultra Wide Band (UWB)
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IEEE 802.15.3 Standards (1/2)

• IEEE 802.15.3 (2003 June)
• Unlicensed 2.4 GHz ISM band (2.4G2.4835G,
  83.5MHz)
• 11, 22, 33, 44, 55 Mbit/s

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IEEE 802.15.3 Standards (2/2)

• IEEE 802.15.3a
• Ultra Wide Band (UWB) technology based
• 3.1G10.6G, 7500MHz (by FCC)
• Project started December 2002
• Planned 2004, delayed
• MBOA (Multi-Band OFDA Alliance) TI Intel
• DS-UWB (Direct Sequence UWB) Motorola/Freescale
  OKI (Japan)
• Disagreements in the task group

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Network Topology

• Piconet (10m range)
• Peer-to-peer communication between devices
• Piconet Coordinator (PNC) is responsible of
  piconet management (beacons, timeslot
  reservation)
• Possibly child piconets
• Maximum of 243 devices in piconet
• Piconet Identifier (PiconetID) is used for
  identifying the piconets

Piconet relationship
Neighbor piconet
Piconet
Child piconet
Data transfer
Child PNC
Neighbor PNC
Piconet Coordinator (PNC)
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Different Piconet Types (1/2)

• If there are no free channel, a device may create
  a dependent piconet
• If two piconets operate in the same channel, one
  is parent piconet and other is dependent piconet
• Dependent piconet
• Child piconet
• PNC belongs as a device in the parent piconet
• Extends the coverage area of the piconet
• Neighbor piconet
• Does not extend the coverage area
• Dependent piconets are
• Autonomous
• They have distinct PiconetIDs
• They use a dedicated time slot from the parent
  PNC called Channel Time Assignment (CTA) to share
  the time between piconets

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Different Piconet Types (2/2)
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Responsibilities of Piconet Coordinator (PNC)

• Periodically sends beacon frames containing
  necessary information for piconet operations
• Supplies timing with the beacon
• Manages QoS, power save modes, and access control
• Assigns time slots to each device and distributes
  payload protection keys
• All devices are not required to be able to act as
  PNC
• This enables cheap and simple implementations

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Network Operations - Piconet Creation

• Device must make sure that there are no existing
  piconets using the same channel
• Passive scanning is used to detect existing
  piconets
• Device goes through all the channels supported by
  the physical layer
• Device listens the beacon frames from PNCs
• A device creating a piconet becomes PNC and has
  the following responsibility
• Selects the channel
• Starts to transmit beacon frames

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Network Operations - Joining to the Piconet

• Piconets are discovered using passive scanning
• Device authenticates with PNC
• Device exchanges the capability information with
  PNC (PHY data rates supported, power management
  status, buffer space, capability to act as PNC
  etc.)
• Device sends association request to join the
  piconet
• PNC sends association response
• After joining to the piconet, the device
  information is broadcast with the beacon

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Network Operations PNC Handover

• Changing PNC during the operation (PNC handover)
• When active PNC leaves the network or runs out of
  battery, another device may take over PNC
  responsibilities
• When new device joins the piconet
• If the new device is more capable and the current
  security policies allow it, then the PNC has the
  option of handing over control of the piconet to
  the device that has just joined
• PNC handover maintains all existing time
  allocations so that there is no interruption in
  the delivery of data in the piconet
• PNC selects the best device among those that have
  the PNC Capable bit set

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Frame Architecture

• CAP
• Allows contention via CSMA/CA
• Command exchange between DEV and PNC
• File transfers from DEV without request
• CTAP
• Time slot allocation specified in the beacon
• Reserved bandwidth for DEV
• MCTA command (PNC?DEV)
• CTA data (DEV?DEV)

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Quality of Service (QoS)

• IEEE 802.15.3 supports various traffic types with
  different QoS requirements
• Best-effort data without reservations (contention
  based)
• PNC allocates resources (slots) for devices
• Devices make requests
• Periodic slot reservation for synchronous data
• Voice, video
• Aperiodic reservation for asynchronous data
• Allocates a certain time for sending packets
• Bursty data transmission file transfer etc.

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Security (2 modes)

• Mode 0 - mandatory
• Device does not use any authentication or
  encryption methods to protect the transmitted
  data
• Access Control List (ACL) is available
• Mode 1 - optional
• Provided security services
• ACL
• Mutual authentication
• Key management key establishment, key transport,
  verifying the authenticity of the keys
• Data encryption
• Message integrity protection (data, beacon,
  commands)
• Freshness