IEEE 802.15 <subject>

1
Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
CTA Advertisement for Overlapping
Piconets Date Submitted Mar. 2004 Source
Song-Lin Young Company Sharp Labs. of America,
Inc. Address 5750 NW Pacific Rim Blvd, Camas,
WA, 98607 Voice1 360 817 7509, FAX 1 360
834 8696, E-Mail syoung_at_sharplabs.com Re
15-04-0034-01-003b-SG3b-Closing-Report-Jan04.ppt
Abstract This document provides the method for
announcement of CTA by non-PNC devices to
uncoordinated piconet. Purpose This
contribution is a response to SG3b call for
submission about proposed amendment of 802.15.3
MAC Standard. Notice This document has been
prepared to assist the IEEE P802.15. It is
offered as a basis for discussion and is not
binding on the contributing individual(s) or
organization(s). The material in this document is
subject to change in form and content after
further study. The contributor(s) reserve(s) the
right to add, amend or withdraw material
contained herein. Release The contributor
acknowledges and accepts that this contribution
becomes the property of IEEE and may be made
publicly available by P802.15.
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CTA Advertisement for Overlapping
PiconetsSong-Lin YoungSharp Labs. of
America, Inc.
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Contents

• Introduction
• Issues associated with PNC/beacon
• CTA announcement mechanism
• Conclusions and future work

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Introduction

• Operations of 15.3 WPAN require devices to find a
  PNC (and its beacons) in order to engage in
  piconet activities.
• Multiple piconet overlapping scenarios are
  expected to occur in a dynamic environment, such
  as home networking.
• Device may start a piconet without knowing the
  existence of a nearby PNC.
• Piconet consisting of portable devices may be
  carried around and brought into area of other
  piconets.
• Changes of topology due to moving objects/people

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Simple Piconet Configuration
Device 1
Beacon
PNC
Beacon
CTA 1
CTA 2
Superframe N
Superframe N1
CTA 2
Beacon
Beacon
PNC 1
CTA 1
CTA 1
Device 1
Device 2
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Overlapping Piconets

1. PNC 2 is not able to hear beacons form PNC 1

1. Device 2 is not able to hear beacons from PNC 1

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Potential Interference Scenario

• Device 1 (PNC 1) is scheduled to transmit during
  the assigned CTA(s)
• PNC 2/Device 2 will be interfered during Device 1
  CTA if two piconets are not coordinated

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Basic Concept

• A mechanism is needed to advertise piconet timing
  and CTA for those unassociated devices not
  covered by PNC
• Extending the coverage area of beacons such that
  superframe timing and CTA information is
  available for
• Making it possible for devices to be aware of
  existing piconets via scan operation.
• Better selection of channel/frequency usage.
• Co-existence by sharing channel time

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Beacon Frame Format
p0 (Superframe starts)
Superframe Duration
Preamble
Header
CTA 1
FCS
CTA 2
CTA 3
CTA n
Dev A Address
Dev B Address
Stream Index
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Quasi-Beacon Frame Format
p0 (Packet starts)
Preamble
Header
Data
FCS
Superframe Duration
CTA n
Frame Control
HCS

• During transmission, the device advertises its
  CTA(s) containing duration and offset from
  beginning of superframe
• Only corresponding CTA of transmitting device are
  advertised.
• Superframe duration can also be included.
• Applicable to Data, command, and Ack frame types.

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Conclusions

• CTA Advertisement
• Solve hidden node problem
• Facilitate the following operations
• Coexistence of multiple piconets
• Coordination/synchronization of piconets
• Device discovery
• Minimum overhead to each packet

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Future Work

• Asymmetric data transfer
• Delay Ack frames which occur less frequently
• Streaming applications
• No Ack frame