1. Date Submitted: [18 March 2004]
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Scaling-TG3a-PHY-Proposals-for-High-Aggregate-Data-Rates]
Date Submitted: [18 March 2004]
Source: [Matt Welborn] Company [Motorola]
Address [8133 Leesburg Pike Vienna, VA USA]
Voice:[ ],
Re: []
Abstract: [A proposal for a common frequency plan for DS-UWB and MB-OFDM to enable a common signaling mode]
Purpose: [Provide technical information to the TG3a voters regarding a possible common signaling mode compromise]
Notice: This document has been prepared to assist the IEEE P 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 P
Welborn Motorola

2. Outline Scaling baseline PHY modes Higher frequency bands
March 2004
Outline
Scaling baseline PHY modes
Higher frequency bands
Higher data rates
Welborn Motorola

3. DS-UWB Operating Bands
March 2004
DS-UWB Operating Bands
Low Band
High Band 3 4 5 6 7 8 9 10 11 3 4 5 6 7 8 9 10 11
GHz
GHz
MB-OFDM Operating Bands
Welborn Motorola

4. Multi-piconet Overview
March 2004
Multi-piconet Overview
DS-UWB low band and high band
2x center frequency & BW in high band
Support for 6 piconets in each of low band and high band
MB-OFDM has added full FDM support for multiple piconets using band groups
New band groups have higher frequencies
All use same TFCs
For both proposals, higher frequency bands will experience worse RF losses
Likely higher receiver noise figures
Welborn Motorola

5. Multipath Ranges for 110 Mbps
March 2004
Multipath Ranges for 110 Mbps *
* Band group 5 has 2 bands  rate or range is lower
Welborn Motorola

6. Assumptions for Comparison
March 2004
Assumptions for Comparison
Assumptions for multiple piconet support
All piconets >5GHz assumed to have +2dB NF
Assume multipath ranges reduced by 20*Log(Fc ratio)
All piconets are outside UNII except Band Group 2
UNII devices ~30dB higher transmit power
802.11a, cordless phone, TDWR, DSRC…
Typical UNII device within about m of BG2 piconet will degrade sensitivity 6dB (~½ range)
Assumes erasure decoding present to partially mitigate UNII RFI
Dynamic UNII protection may increase NF/BOM (03/141r3, p.12)
Seems unlikely that this would be acceptable to user/OEM
Does not meet selection criteria of <1 m for a separation
Assumptions about acceptable distance ratio, 2 cases
Distance ratio of <=1.5 is required for multi-piconet support
Distance ratio of <=1.0 is required for multi-piconet support
Assumes adequate adjacent band/band group isolation
Welborn Motorola

7. Piconets & Multipath Range
March 2004
Piconets & Multipath Range
Band Group 2 shown
degraded 6 dB (UNII
Device at m)
Band Group 4
With 2 “piconets”
Welborn Motorola

8. Piconets & Multipath Range
March 2004
Piconets & Multipath Range
Band Group 2 shown
degraded 6 dB (UNII
Device at m)
Band Group 4
With 1 “piconets”
Welborn Motorola

9. DS-UWB scaling to Higher Rates
March 2004
DS-UWB scaling to Higher Rates
There is significant interest in “cable replacement” applications that require high speed operation (480+ Mbps) at short range
DS-UWB operation at 500 Mbps uses L=2 code & ¾ FEC
Complexity is similar DS-UWB receiver for 110 & 220 Mbps
Same ADC bit widths & clock rates
Same rake bit width & complexity
Fewer rake taps available (only 2/3 as many as for 220 Mbps)
Viterbi decoder for k=6, rate ¾ likely 2x gates  45k gate increase
Operation at 660 Mbps also supported with un-coded operation
4.9 m range in fully impaired AWGN simulation
Eliminates requirement for high speed Viterbi decoder
Complete, fully impaired multipath simulations for Mbps DS-UWB are underway
Welborn Motorola

10. MB-OFDM scaling to Higher Rates
March 2004
MB-OFDM scaling to Higher Rates
Currently available complexity estimates for MB-OFDM implementations do not support operation at > 200 Mbps
Document 267r5, p. 35
Estimated MB-OFDM receiver complexity scaling for 480 Mbps
5-bit ADC required instead of 4-bit ADC at lower rates (Doc# 03/267)
Increased bit-width for internal FFT processing
45 bits is 25% increase  assume 25% higher gate count (conservative)
This scales FFT engine from k gates to k 85 MHz
25k gate increase over current estimates for 200 Mbps implementation
K=7 Viterbi decoder does not operate at 480 Mbps
SiWorks (Document 03/213r0) estimates that 480 Mbps, k=7 operation would be possible, but would require a 4-wide parallel implementation
SiWorks estimate for 200 Mbps k=7 Viterbi is 75k gates at 100 MHz
Equivalent to 88 k gates at 85.5 MHz
SiWorks estimate for 480 Mbps is 110K gates at 120 MHz  154k gates at 85.5 MHz (about 2x the <=200 Mbps Viterbi complexity)
K=7 Viterbi decoder would require an increase of 80k 85MHz
Welborn Motorola

11. DS-UWB & MB-OFDM Complexity Scaling
March 2004
DS-UWB & MB-OFDM Complexity Scaling
Complexity increase for MB-OFDM receiver
Increase for FFT & Viterbi is >100k 85 MHz
Total complexity now >550 k gates at 85.5 MHz
Based on estimate of 295k gates at 132 MHz
Complexity increase for DS-UWB receiver
Increase in gate count due only to Viterbi decoder, 54k gates
Total receiver complexity now ~230 k gates at 85.5 Mhz
For un-coded operation at 660 Mbps, no Viterbi decoder
Power consumption equivalent to 130 k gates at 85.5 MHz
DS-UWB digital baseband complexity is only ~30-40% of the equivalent MB-OFDM implementation
Welborn Motorola