1. Project: IEEE 802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Compromise Proposal]
Date Submitted: [12Sept2004]
Source: [John Barr] Company [Motorola]
Address [1303 E. Golf Road, Schuamburg, IL 60196]
Voice:[ ], FAX: [ ],
Re: [7September2004 from a Task Group Chair]
Abstract: [Proposal for a compromise solution for a]
Purpose: [Provide proposal to conclude the current a down selection process and proceed with the drafting of an acceptable standard.]
Notice: This document has been prepared to assist the IEEE 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
January 2004
doc.: IEEE /0478r0
Dr. John R. Barr, Motorola
John Barr, Motorola

2. Compromise Proposal
The Merger #2 Team has repeatedly suggested that a compromise would benefit the a process.
The Common Signaling Mode (CSM) was suggested as a result of an a ad hoc meeting in February.
The definition of a BM plus the option to use MB-OFDM or DS-UWB (or both) to meet 110 Mbps requirements is proposed
Dr. John R. Barr, Motorola

3. Essential Compromise Definition
One mode defined as mandatory in all a standard devices:
Minimum data rate of 9.2 Mbps
Maps onto spectrum plans of both MB-OFDM and DS-UWB
Minimizes additional complexity of current MB-OFDM and DS-UWB proposals
One additional mode selected from MB_OFDM or DS-UWB to meet minimum PAR requirements:
110 Mbps at 10m
Higher data rates are optional
Default mode is BM for beacons, PNC commands, and broadcast
Native mode allows MB-OFDM or DS-UWB to be used for beacons, PNC commands and broadcast
pseudo BM beacon sent every N beacons
CAP or CTA for BM association at least every N beacons
Dr. John R. Barr, Motorola

4. Device Types for the BM Compromise
Three classes of devices
Device with BM + MB-OFDM
Device with BM + DS-UWB
Device with BM + DS-UWB + MB-OFDM
Upper layers
MAC
MB-OFDM BM
Upper layers
Upper layers
Upper layers
MAC
MAC
MAC
MB-OFDM
MB-OFDM
CSM BM BM
MB-OFDM
DS-UWB
Dr. John R. Barr, Motorola

5. MB-OFDM & DS-UWB Signal Spectrum with BM Compromise Solution
MB-OFDM (3-band)
Theoretical Spectrum
Relative
PSD (dB)
Proposed Base
Mode Band
(500 MHz bandwidth)
DS-UWB Low Band
Pulse Shape (RRC) -3
-20
3432
3960
4488
3100
5100
Frequency (MHz)
FCC Mask
Dr. John R. Barr, Motorola

6. Three Types of 802.15.3a Piconet Operation
“BM piconet”
All beacons & commands passed in BM-9.2 Mbps
PNC requires only baseline BM modes be implemented
DEV can use BM or high rate modes in assigned CTAs
“MB-OFDM piconet”
Many (or all) members are MB-OFDM capable (required for PNC)
MB-OFDM beacons + 1-in-N BM beacons
“DS-UWB piconet”
Many (or all) members are DS-UWB capable (required for PNC)
DS-UWB beacons + 1-in-N BM beacons
Dr. John R. Barr, Motorola

7. a Piconet Types
All piconets enable association by all 15.3a devices
BM-only, (DS-UWB+BM) or (MB-OFDM+BM)
“BM Piconet” supports all classes of devices in an equivalent manner
Higher performance modes (DS-UWB or MB-OFMD) in CTAs
Other piconets can be “optimized” to support either MB-OFDM or DS-UWB operations
Non-native DEVs might have slightly lower performance
Slightly higher overhead when BM beacons are used
Longer association times (depends on beaconing parameters)
Dr. John R. Barr, Motorola

8. Example “MB-OFDM Piconet”
Uses MB-OFDM for beaconing and control
No performance impact except occasional BM beacon (transmitted only1-in-N superframes)
MB-OFDM devices can be implemented with highly “sub-optimal” BM receivers
Performance of BM implementation does not impact MB-OFDM beacons or PNC or DEV operating ranges
All devices can still transmit “high quality” BM
BM receiver complexity can be essentially zero – no rake or equalizer required to be compliant
“One finger rake” can make symbol decision on ADC values
BM receiver performance only limits ‘Interoperability range”
Dr. John R. Barr, Motorola

9. Beacons for an “MB-OFDM Piconet”
BM Beacon + Assoc. CAP
MB-OFDM Beacon 1 2 N
N+1 …
CTA
Superframe Duration #
MB-OFDM Capable PNC transmits all beacons using MB-OFDM
One-in-N superframes the PNC also transmits BM beacon to advertise interoperability & support non-MB-OFDM DEVs
Performance controlled / impact limited by 1-in-N BM beacon
Dr. John R. Barr, Motorola

10. Compromise Proposal Conclusions
Allows extremely simple BM implementations for all DEVs
BM implementation complexity chosen by DEV manufacturer
“Native modes” for piconets allow uncompromised performance
Doesn’t depend on BM performance for robust piconet performance
Sub-optimal BM only impacts performance during “interoperation”
Baseline BM piconet operation
BM transmissions for interoperation in DS-UWB/MB-OFDM piconets
The task group needs to determine how to define the Base Mode
Dr. John R. Barr, Motorola