July 2003
doc.: IEEE 802.15-03/267r1
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Multi-band OFDM Physical Layer Proposal]
Date Submitted: [14 July, 2003]
Source: [Presenter: Anuj Batra] Company [Texas Instruments]
[see page 2,3 for the complete list of company names and authors]
Address [12500 TI Blvd, MS 8649, Dallas, TX 75243]
Voice:[214-480-4220], FAX: [972-761-6966], E-Mail:[batra@ti.com]
Re: [This submission is in response to the IEEE P802.15 Alternate PHY Call for Proposal (doc. 02/372r8)
that was issued on January 17, 2003.]
Abstract: [This document describes the Multi-band OFDM proposal for IEEE 802.15 TG3a.]
Purpose: [For discussion by IEEE 802.15 TG3a.]
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.
Submission
Slide 1
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
This contribution is a technical merger between*:
Texas Instrument [03/141]: Batra
and
\
femto Devices [03/101]: Cheah
FOCUS Enhancements [03/103]: Boehlke
General Atomics [03/103]: Ellis
Institute for Infocomm Research [03/107]: Chin
Intel [03/109]: Brabenac
Mitsubishi Electric [03/111]: Molisch
Panasonic [03/121]: Mo
Philips [03/125]: Kerry
Samsung Advanced Institute of Technology [03/135]: Kwon
Samsung Electronics [03/133]: Park
SONY [03/137]: Fujita
Staccato Communications [03/099]: Aiello
Time Domain [03/143]: Kelly
Wisair [03/151]: Shor
* For a complete list of authors, please see page 3.
Submission
Slide 2
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Authors
femto Devices: J. Cheah
FOCUS Enhancements: K. Boehlke
General Atomics: J. Ellis, N. Askar, S. Lin, D. Furuno, D. Peters, G. Rogerson, M. Walker
Institute for Infocomm Research: F. Chin, Madhukumar, X. Peng, Sivanand
Intel: J. Foerster, V. Somayazulu, S. Roy, E. Green, K. Tinsley, C. Brabenac, D. Leeper, M. Ho
Mitsubishi Electric: A. F. Molisch, Y.-P. Nakache, P. Orlik, J. Zhang
Panasonic: S. Mo
Philips: C. Razzell, D. Birru, B. Redman-White, S. Kerry
Samsung Advanced Institute of Technology: D. H. Kwon, Y. S. Kim
Samsung Electronics: M. Park
SONY: E. Fujita, K. Watanabe, K. Tanaka, M. Suzuki, S. Saito, J. Iwasaki, B. Huang
Staccato Communications: R. Aiello, T. Larsson, D. Meacham, L. Mucke
Texas Instruments: A. Batra, J. Balakrishnan, A. Dabak, R. Gharpurey, J. Lin, P. Fontaine,
J.-M. Ho, S. Lee, M. Frechette, S. March, H. Yamaguchi
Time Domain: J. Kelly, M. Pendergrass
Wisair: G. Shor, Y. Knobel, D. Yaish, S. Goldenberg, A. Krause, E. Wineberger, R. Zack, B. Blumer,
Z. Rubin, D. Meshulam, A. Freund
Submission
Slide 3
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Overview of OFDM
 OFDM was invented more than 40 years ago.
 OFDM has been adopted for several technologies:





Asymmetric Digital Subscriber Line (ADSL) services.
IEEE 802.11a/g.
IEEE 802.16a.
Digital Audio Broadcast (DAB).
Digital Terrestrial Television Broadcast: DVD in Europe, ISDB in Japan
 OFDM is also being considered for 4G, IEEE 802.11n, IEEE 802.16,
and IEEE 802.20.
Submission
Slide 4
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Strengths of OFDM
 OFDM is spectrally efficient.
 IFFT/FFT operation ensures that sub-carriers do not interfere with each
other.
 OFDM has an inherent robustness against narrowband interference.
 Narrowband interference will affect at most a couple of tones.
 Information from the affected tones can be erased and recovered via the
forward error correction (FEC) codes.
 OFDM has excellent robustness in multi-path environments.
 Cyclic prefix preserves orthogonality between sub-carriers.
 Cyclic prefix allows the receiver to capture multi-path energy more
efficiently.
Submission
Slide 5
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Worldwide Compliance
 Bands and tones can be dynamically turned on and off in order to
comply with changing world-wide regulations.
 By using OFDM, small and narrow bandwidths can easily be protected
by turning off tones near the frequencies of interest.
 For example, consider the radio-astronomy bands allocated in Japan.
Only need to zero out a few tones in order to protect these services.
3260 - 3267 MHz
Channel #1 - Typical OFDM waveform f
Submission
Slide 6
3332 - 3339 MHz
3345.8 - 3352.5 MHz
Channel #1 - Waveform with Japanese f
radioastronomical bands protected.
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Details of the
Multi-band OFDM System
*More details about the Multi-band OFDM system
can be found in the latest version of 03/268.
Submission
Slide 7
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Overview of Multi-band OFDM
 Basic idea: divide spectrum into several 528 MHz bands.
 Information is transmitted using OFDM modulation on each band.
 OFDM carriers are efficiently generated using an 128-point IFFT/FFT.
 Internal precision is reduced by limiting the constellation size to QPSK.
 Information bits are interleaved across all bands to exploit frequency
diversity and provide robustness against multi-path and interference.
 60.6 ns cyclic prefix provides robustness against multi-path even in the
worst channel environments.
 9.5 ns guard interval provides sufficient time for switching between
bands.
Submission
Slide 8
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-band OFDM: TX Architecture
 Block diagram of an example TX architecture:
Input
Data
Scrambler
Convolutional
Encoder
Puncturer
Bit
Interleaver
Constellation
Mapping
IFFT
Insert Pilots
Add CP & GI
DAC
exp(j2fct)
Time-Frequency Code
 Architecture is similar to that of a conventional and proven OFDM
system. Can leverage existing OFDM solutions for the development of
the Multi-band OFDM physical layer.
 For a given superframe, the time-frequency code is specified in the
beacon by the PNC. The time-frequency code is changed from one
superframe to another in order to randomize multi-piconet interference.
Submission
Slide 9
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-band OFDM System Parameters
 System parameters for mandatory and optional data rates:
Info. Data Rate
55 Mbps*
80 Mbps**
110 Mbps*
160 Mbps**
200 Mbps*
320 Mbps**
480 Mbps**
Modulation/Constellation
OFDM/QPSK
OFDM/QPSK
OFDM/QPSK
OFDM/QPSK
OFDM/QPSK
OFDM/QPSK
OFDM/QPSK
FFT Size
128
128
128
128
128
128
128
Coding Rate (K=7)
R = 11/32
R = 1/2
R = 11/32
R = 1/2
R = 5/8
R = 1/2
R = 3/4
Spreading Rate
4
4
2
2
2
1
1
Information Tones
25
25
50
50
50
100
100
Data Tones
100
100
100
100
100
100
100
Info. Length
242.4 ns
242.4 ns
242.4 ns
242.4 ns
242.4 ns
242.4 ns
242.4 ns
Cyclic Prefix
60.6 ns
60.6 ns
60.6 ns
60.6 ns
60.6 ns
60.6 ns
60.6 ns
Guard Interval
9.5 ns
9.5 ns
9.5 ns
9.5 ns
9.5 ns
9.5 ns
9.5 ns
Symbol Length
312.5 ns
312.5 ns
312.5 ns
312.5 ns
312.5 ns
312.5 ns
312.5 ns
Channel Bit Rate
640 Mbps
640 Mbps
640 Mbps
640 Mbps
640 Mbps
640 Mbps
640 Mbps
Multi-path Tolerance
60.6 ns
60.6 ns
60.6 ns
60.6 ns
60.6 ns
60.6 ns
60.6 ns
* Mandatory information data rate, ** Optional information data rate
Submission
Slide 10
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Simplified TX Analog Section
 For rates up to 200 Mb/s, the input to the IFFT is forced to be conjugate
symmetric (for spreading gains  2).
 Output of the IFFT is REAL.
 The analog section of TX can be simplified when the input is real:
 Need to only implement the “I” portion of DAC and mixer.
 Only requires half the analog die size of a complete “I/Q” transmitter.
Input
Data
Scrambler
Convolutional
Encoder
Puncturer
Bit
Interleaver
Constellation
Mapping
IFFT
Insert Pilots
Add CP & GI
DAC
cos(2fct)
Time Frequency Code
 For rates > 200 Mb/s, need to implement full “I/Q” transmitter.
Submission
Slide 11
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
More Details on the OFDM Parameters
 By using a contiguous set of orthogonal carriers, the transmit spectrum will
always occupy a bandwidth greater than 500 MHz.

Total of 128 tones:




100 data tones used to transmit information (constellation: QPSK).
12 pilot tones used for carrier and phase tracking.
10 user-defined pilot tones.
Remaining 6 tones including DC are NULL tones.
 User-defined pilot tones:
 Carry no useful information.
 Energy is placed on these tones to ensure that the spectrum has a bandwidth
greater than 500 MHz.
 Can trade the amount of energy placed on tones for relaxing analog filtering
specifications.
 Ultimately, the amount of energy placed on these tones is left to the implementer.
Provides a level of flexibility for the implementer.
Submission
Slide 12
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Band Plan (1)
 Group the 528 MHz bands into 4 distinct groups.
GROUP B
GROUP A
GROUP C
GROUP D
Band
#1
Band
#2
Band
#3
Band
#4
Band
#5
Band
#6
Band
#7
Band
#8
Band
#9
Band
#10
Band
#11
Band
#12
Band
#13
3432
MHz
3960
MHz
4488
MHz
5016
MHz
5808
MHz
6336
MHz
6864
MHz
7392
MHz
7920
MHz
8448
MHz
8976
MHz
9504
MHz
10032
MHz




f
Group A: Intended for 1st generation devices (3.1 – 4.9 GHz).
Group B: Reserved for future use (4.9 – 6.0 GHz).
Group C: Intended for devices with improved SOP performance (6.0 – 8.1 GHz).
Group D: Reserved for future use (8.1 – 10.6 GHz).
Submission
Slide 13
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Band Plan (2)
 The relationship between the center frequency fc and the band number
nb is:
2904  528  nb
f c (nb )  
3168  528  nb
nb  1,,4
nb  5,,13
BAND_ID (nb)
Lower
Frequency
(fl)
Center
Frequency
(fc)
Higher
Frequency
(fh)
BAND_ID (nb)
Lower
Frequency
(fl)
Center
Frequency
(fc)
Higher
Frequency
(fh)
1
3168 MHz
3432 MHz
3696 MHz
8
7128 MHz
7392 MHz
7656 MHz
2
3696 MHz
3960 MHz
4224 MHz
9
7656 MHz
7920 MHz
8184 MHz
3
4224 MHz
4488 MHz
4752 MHz
10
8184 MHz
8448 MHz
8712 MHz
4
4752 MHz
5016 MHz
5280 MHz
11
8712 MHz
8976 MHz
9240 MHz
5
5544 MHz
5808 MHz
6072 MHz
12
9240 MHz
9504 MHz
9768 MHz
6
6072 MHz
6336 MHz
6600 MHz
13
9768 MHz
10032 MHz
10296 MHz
7
6600 MHz
6864 MHz
7128 MHz
Submission
Slide 14
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-mode Multi-band OFDM Devices (1)
 Having multiple groups of bands enables multiple modes of operations
for multi-band OFDM devices.
 Different modes for multi-band OFDM devices are:
Mode
Frequency of Operation
Number of Bands
Mandatory / Optional
1
Bands 1–3 (A)
3
Mandatory
2
Bands 1–3, 6–9 (A,C)
7
Optional
 Future expansion into groups B and D will enable an increase in the
number of modes.
Submission
Slide 15
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-mode Multi-band OFDM Devices (2)
 Frequency of operation for a Mode 1 device:
Band
#1
Band
#2
Band
#3
3432
MHz
3960
MHz
4488
MHz
f
 Frequency of operation for a Mode 2 device:
Submission
Band
#1
Band
#2
Band
#3
Band
#6
Band
#7
Band
#8
Band
#9
3432
MHz
3960
MHz
4488
MHz
6336
MHz
6864
MHz
7392
MHz
7920
MHz
Slide 16
f
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Frequency Synthesis (1)
 Example: frequency synthesis for Mode 1 (3-band) device:
Sampling
Clock
528 MHz
Select
4224 MHz
PLL
/8
264 MHz
/2
SSB
792 MHz
SSB
Desired
Center
Frequency
 A single PLL can also be used to generate the center
frequencies for a Mode 2 (7-band) device.
Submission
Slide 17
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Frequency Synthesis (2)
 Circuit-level simulation of frequency synthesis:
Switching Time = ~2 ns
Switching Time = ~2 ns
 Nominal switching time = ~2 ns.
 Need to use a slightly larger switching time to allow for process and
temperature variations.
Submission
Slide 18
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-band OFDM: PLCP Frame Format
 PLCP frame format:
RATE
3 bits
PLCP Preamble
Reserved
1 bit
PHY
Header
LENGTH
12 bits
MAC
Header
Scrambler Init
2 bits
HCS
55 Mb/s
Tail
Bits
Frame Payload
Variable Length: 0  4095 bytes
FCS
Tail
Bits
Pad
Bits
55, 80, 110, 160, 200, 320, 480 Mb/s
 Rates supported: 55, 80, 110, 160, 200, 320, 480 Mb/s.

Support for 55, 110, and 200 Mb/s is mandatory.

Preamble + Header length = 11.56 ms. Burst preamble + Header length = 4.69 ms.

Preamble + Header length = 14.06 ms. Burst preamble + Header length = 7.19 ms.
 Mode 1 (3-band):
 Mode 2 (7-band):
 Header is sent at an information data rate of 55 Mb/s.
 Maximum frame payload supported is 4095 bytes.
Submission
Slide 19
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multiple Access
 Multiple piconet performance is governed by the bandwidth expansion
factor.
 Bandwidth expansion can be achieved using any of the following
techniques or combination of techniques:
 Spreading, Time-frequency interleaving, Coding
 Ex: Multi-band OFDM obtains its BW expansion by using all 3 techniques.
 Time Frequency Codes:
Channel
Number
Preamble
Pattern
1
1
1
2
3
1
2
3
1
2
3
4
5
6
7
2
2
1
3
2
1
3
2
1
7
6
5
4
3
2
3
3
1
1
2
2
3
3
1
4
7
3
6
2
5
4
4
1
1
3
3
2
2
1
3
5
7
2
4
6
Submission
Mode 1 DEV: 3-band
Length 6 TFC
Slide 20
Mode 1 DEV: 7-band
Length 7 TFC
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
PLCP Preamble (1)
 Multi-band OFDM preamble is composed of 3 sections:
 Packet sync sequence: used for packet detection.
 Frame sync sequence: used for boundary detection.
 Channel estimation sequence: used for channel estimation.
 Packet and frame sync sequences are constructed from the same
hierarchical sequence.
 Correlators for hierarchical sequences can be implemented efficiently:
 Low gate count.
 Extremely low power consumption.
 Sequences are designed to be the most robust portion of the packet.
Submission
Slide 21
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
PLCP Preamble (2)
 Preamble needs to be designed to allow both Mode 1 (3-band) and Mode 2
(7-band) devices to operate in the same piconet.
 All devices in the same piconet must be able to detect the preamble and demodulate
PHY/MAC header.
 Preamble structure for Mode 1 (3-band) device:
Band #9
End of Synch
Indicator
Band #8
Synchronizaton
(24 symbols)
Band #7
Band #6
Channel
Estimation
Band #3
Header
Synchronization
Payload
Channel Estimation
p
Band #2
Header
p
Band #1
Payload
p
11.5625 usec (Preamble + Header)
Time
 End of synchronization pattern [p1,p2,p3] is used to indicate that the interleaving
sequence remains constant throughout the packet.
Submission
Slide 22
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
PLCP Preamble (3)
 Preamble structure for Mode 2 (7-band) device:
Synchronization
Header
Channel Estimation
Payload
Band #9
Band #8
Band #7
Band #6
Payload
End of Synch
Indicator
Synchronizaton
(24 symbols)
Channel Estimation
Lower 3 Bands
Band #3
p
Band #2
Band #1
Channel Estimation Upper 4 Bands
+
Header on Lower 3 Bands
p
p
14.0625 usec (Preamble + Header)
Time
 Preamble/header are transmitted on bands 1–3 using length 6 interleaving
sequences, so Mode 1 (3-band) devices can correctly decode the header.
 End of synchronization pattern [p4,p5,p6] is used to indicate the transition to
length 7 interleaving sequence.
Submission
Slide 23
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
PLCP Preamble (4)
 In the multiple overlapping piconet case, it is desirable to use different hierarchical
preambles for each of the piconets.
 Basic idea: define 4 hierarchical preambles, with low cross-correlation values.
 Preambles are generated by spreading a length 16 sequence by a length 8 sequence.
Preamble Pattern
Sequence A
1
1
1
1
1
-1
-1
-1
1
-1
1
-1
1
1
-1
1
1
2
-1
1
1
-1
1
-1
-1
-1
-1
1
1
1
-1
1
1
1
3
-1
1
1
1
1
1
-1
-1
1
1
-1
1
-1
1
1
-1
4
1
-1
-1
1
1
-1
1
-1
1
-1
-1
-1
-1
-1
-1
1
Preamble Pattern
Sequence B
Spreader
1
1
1
-1
1
1
-1
-1
-1
2
-1
1
-1
-1
1
1
1
-1
3
-1
1
-1
-1
1
1
1
-1
4
1
1
-1
1
1
-1
-1
-1
Submission
Slide 24
Sequence A
(length 16)
Sequence C
(length 128)
Sequence B
(length 8)
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Link Budget and Receiver Sensitivity
 Assumption: Mode 1 DEV (3-band), AWGN, and 0 dBi gain at TX/RX antennas.
Submission
Parameter
Value
Value
Value
Information Data Rate
110 Mb/s
200 Mb/s
480 Mb/s
Average TX Power
-10.3 dBm
-10.3 dBm
-10.3 dBm
Total Path Loss
64.2 dB
(@ 10 meters)
56.2 dB
(@ 4 meters)
50.2 dB
(@ 2 meters)
Average RX Power
-74.5 dBm
-66.5 dBm
-60.5 dBm
Noise Power Per Bit
-93.6 dBm
-91.0 dBm
-87.2 dBm
CMOS RX Noise Figure
6.6 dB
6.6 dB
6.6 dB
Total Noise Power
-87.0 dBm
-84.4 dBm
-80.6 dBm
Required Eb/N0
4.0 dB
4.7 dB
4.9 dB
Implementation Loss
2.5 dB
2.5 dB
3.0 dB
Link Margin
6.0 dB
10.7 dB
12.2 dB
RX Sensitivity Level
-80.5 dBm
-77.2 dBm
-72.7 dB
Slide 25
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Link Budget and Receiver Sensitivity
 Assumption: Mode 2 DEV (7-band), AWGN, and 0 dBi gain at TX/RX antennas.
Submission
Parameter
Value
Value
Value
Information Data Rate
110 Mb/s
200 Mb/s
480 Mb/s
Average TX Power
-6.6 dBm
-6.6 dBm
-6.6 dBm
Total Path Loss
66.6 dB
(@ 10 meters)
58.6 dB
(@ 4 meters)
52.6 dB
(@ 2 meters)
Average RX Power
-73.2 dBm
-65.2 dBm
-59.2 dBm
Noise Power Per Bit
-93.6 dBm
-91.0 dBm
-87.2 dBm
CMOS RX Noise Figure
8.6 dB
8.6 dB
8.6 dB
Total Noise Power
-85.0 dBm
-82.4 dBm
-78.6 dBm
Required Eb/N0
4.0 dB
4.7 dB
4.9 dB
Implementation Loss
2.5 dB
2.5 dB
3.0 dB
Link Margin
5.3 dB
10.0 dB
11.5 dB
RX Sensitivity Level
-78.5 dBm
-75.2 dBm
-70.7 dB
Slide 26
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
System Performance (Mode 1: 3-band)
 The distance at which the Multi-band OFDM system can achieve a
PER of 8% for a 90% link success probability is tabulated below:
*
Range*
AWGN
CM1
CM2
CM3
CM4
110 Mbps
20.5 m
11.5 m
10.9 m
11.6 m
11.0 m
200 Mbps
14.1m
6.9 m
6.3 m
6.8 m
5.0 m
480 Mbps
7.8 m
2.9 m
2.6 m
N/A
N/A
Includes losses due to front-end filtering, clipping at the DAC, ADC degradation,
multi-path degradation, channel estimation, carrier tracking, packet acquisition,
etc.
Submission
Slide 27
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Simultaneously Operating Piconets (1)
 Assumptions:
 Mode 1 DEV (3-band) operating at a data rate of 110 Mbps.
 Simultaneously operating piconet performance as a function of the
multipath channel environments:
Channel Environment
1 piconet
2 piconet
3 piconet
CM1 (dint/dref)
0.91
1.18
1.45
CM2 (dint/dref)
0.83
1.24
1.47
CM3 (dint/dref)
0.94
1.21
1.46
CM4 (dint/dref)
1.15
1.53
1.85
 Results incorporate SIR estimation at the receiver.
Submission
Slide 28
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Simultaneously Operating Piconets (2)
 Assumptions:
 Mode 2 DEV (7-band) operating at a data rate of 110 Mbps.
 Simultaneously operating piconet performance as a function of the
multipath channel environments:
Channel Environment
1 piconet
2 piconet
3 piconet
CM1 (dint/dref)
0.47
0.65
0.86
CM2 (dint/dref)
0.43
0.64
0.80
CM3 (dint/dref)
0.49
0.66
0.81
CM4 (dint/dref)
0.61
0.84
1.01
 Results incorporate SIR estimation at the receiver.
Submission
Slide 29
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Signal Robustness/Coexistence
 Assumption: Received signal is 6 dB above sensitivity.
 Value listed below are the required distance or power level needed to
obtain a PER  8% for a 1024 byte packet and a Mode 1 DEV (3-band).
Interferer
Value
IEEE 802.11b @ 2.4 GHz
dint  0.2 meter
IEEE 802.11a @ 5.3 GHz
dint  0.2 meter
Modulated interferer*
SIR  -3.6 dB
Tone interferer*
SIR  -5.6 dB
* Results can be further improved by erasing all the information from the affected band.
 Coexistence with 802.11a/b and Bluetooth is relatively straightforward
because these bands are completely avoided.
Submission
Slide 30
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
PHY-SAP Throughput
 Assumptions:



MPDU (MAC frame body + FCS) length is 1024 bytes.
SIFS = 10 ms.
MIFS = 2 ms.
Number of frames
Throughput @ 110 Mb/s
Throughput @ 200 Mb/s
Throughput @ 480 Mb/s
1
Mode 1: 84.8 Mb/s
Mode 2: 82.7 Mb/s
Mode 1: 130.4 Mb/s
Mode 2: 125.4 Mb/s
Mode 1: 211.4 Mb/s
Mode 2: 198.6 Mb/s
5
Mode 1: 94.8 Mb/s
Mode 2: 92.1 Mb/s
Mode 1: 155.6 Mb/s
Mode 2: 148.5 Mb/s
Mode 1: 286.4 Mb/s
Mode 2: 263.4 Mb/s
 Assumptions:

MPDU (MAC frame body + FCS) length is 4024 bytes.
Number of frames
Throughput @ 110 Mb/s
Throughput @ 200 Mb/s
Throughput @ 480 Mb/s
1
Mode 1: 102.3 Mb/s
Mode 2: 101.5 Mb/s
Mode 1: 175.9 Mb/s
Mode 2: 173.5 Mb/s
Mode 1: 362.4 Mb/s
Mode 2: 352.4 Mb/s
5
Mode 1: 105.7 Mb/s
Mode 2: 104.8 Mb/s
Mode 1: 186.3 Mb/s
Mode 2: 183.6 Mb/s
Mode 1: 409.2 Mb/s
Mode 2: 396.5 Mb/s
Submission
Slide 31
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Complexity (1)
 Unit manufacturing cost (selected information):
 Process: CMOS 90 nm technology node in 2005.
 CMOS 90 nm production will be available from all major SC foundries by early
2004.
 Die size for Mode 1 (3-band) device:
90 nm
130 nm
* Component area.
Complete Analog*
Complete Digital
2.7 mm2
1.9 mm2
3.0 mm2
3.8 mm2
 Die size for Mode 2 (7-band) device:
90 nm
130 nm
* Component area.
Submission
Complete Analog*
Complete Digital
2.9 mm2
1.9 mm2
3.2 mm2
3.8 mm2
Slide 32
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Complexity (2)
 Active CMOS power consumption for Mode 1 (3-band) and Mode 2
(7-band) devices:
Block
Mode1: 90 nm
Mode 2: 90 nm
Mode 1: 130 nm
Mode 2: 130 nm
TX AFE (110, 200 Mb/s)
76 mW
133 mW
91 mW
160 mW
TX Digital (110, 200 Mb/s)
17 mW
17 mW
26 mW
26 mW
TX Total (110 Mb/s)
93 mW
150 mW
117 mW
186 mW
RX AFE (110, 200 Mb/s)
101 mW
155 mW
121 mW
187 mW
RX Digital (110 Mb/s)
54 mW
54 mW
84 mW
84 mW
RX Digital (200 Mb/s)
68 mW
68 mW
106 mW
106 mW
RX Total (110 Mb/s)
155 mW
209 mW
205 mW
271 mW
RX Total (200 Mb/s)
169 mW
223 mW
227 mW
293 mW
Deep Sleep
15 mW
15 mW
18 mW
18 mW
Submission
Slide 33
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Complexity (3)
 Manufacturability:
 Leveraging standard CMOS technology results in a straightforward
development effort.
 OFDM solutions are mature and have been demonstrated in ADSL and
802.11a/g solutions.
 Scalability with process:
 Digital section complexity/power scales with improvements in technology
nodes (Moore’s Law).
 Analog section complexity/power scales slowly with technology node.
 Time to market: the earliest complete CMOS PHY solutions would be
ready for integration is 2005.
 Size: Solutions for PC card, compact flash, memory stick, SD memory in
2005.
Submission
Slide 34
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Scalability of Multi-band OFDM
 Data rate scaling: from 55 Mb/s to 480 Mb/s.
 Frequency scaling:


Mode 1 (3-bands) and optional Mode 2 (7-band) devices.
Guaranteed interoperability between different mode devices.
 Complexity scaling:



Mandatory data rates ( 200 Mbps) only required a single DAC and mixer for the TX
chain  reduced complexity.
Digital section will scale with future CMOS process improvements.
Implementers could always trade-off complexity for performance.
 Power scaling:


Submission
A half-rate Pulse Repetition Frequency (PRF) approach can increase the off time to
enable power saving modes of operation (see back-up slide).
Implementers could always trade-off power consumption for range and information
data rate.
Slide 35
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Comparison of OFDM Technologies

Qualitative comparison between Multi-band OFDM and IEEE 802.11a OFDM:
Criteria
PA Power Consumption
ADC Power Consumption
Multi-band OFDM
Strong Advantage
Multi-band OFDM
Slight Advantage
3

1
FFT Complexity
Viterbi Decoder Complexity
Band Select Filter
Power Consumption
Band Select Filter Area
ADC Precision

Digital Precision
Phase Noise Requirements
Sensitivity to
Frequency/Timing Errors
Design of Radio
Power / Mbps




Neutral
802.11a
Slight Advantage
802.11a
Strong Advantage
2




1. Assumes a 256-point FFT for IEEE 802.11a device.
2. Assumes a 128-point FFT for IEEE 802.11a device.
3. Even though the Multi-band OFDM ADC runs faster than the IEEE 802.11a ADC, the bit precision requirements are significantly smaller, therefore the
Multi-OFDM ADC will consume much less power.
Submission
Slide 36
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-band OFDM Advantages (1)
 Suitable for CMOS implementation (all components).
 Only one transmit and one receive chain at all times, even in the
presence of multi-path.
 Antenna and pre-select filter are easier to design (can possibly use offthe-shelf components).
 Early time to market!
 Low cost, low power, and CMOS integrated solution leads to:
 Early market adoption!
Submission
Slide 37
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-band OFDM Advantages (2)
 Inherent robustness in all the expected multipath environments.
 Excellent robustness to ISM, U-NII, and other generic narrowband
interference.
 Ability to comply with world-wide regulations:
 Bands and tones can be dynamically turned on/off to comply with
changing regulations.
 Coexistence with current and future systems:
 Bands and tones can be dynamically turned on/off for enhanced
coexistence with the other devices.
 Scalability with process:
 Digital section complexity/power scales with improvements in technology
nodes (Moore’s Law).
 Analog section complexity/power scales slowly with technology node.
Submission
Slide 38
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Summary
 The proposed system is specifically designed to be a low power, low
complexity all CMOS solution.
 Expected range for 110 Mb/s: 20.5 meters in AWGN, and greater than
11 meters in multipath environments.
 Expected power consumption for 110 Mb/s:
 Mode 1 DEV: 117 mW (TX), 205 mW (RX), 18 mW (deep sleep) for 130 nm.
 Mode 2 DEV: 186 mW (TX), 271 mW (RX), 18 mW (deep sleep) for 130 nm.
 Multi-band OFDM is coexistence friendly and complies with world-wide
regulations.
 Multi-band OFDM offers multi-mode devices (scalability).
 Multi-band OFDM offers the best trade-off between the various system
parameters.
Submission
Slide 39
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Backup slides
Submission
Slide 40
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Self-evaluation Matrix (1)
REF.
Unit Manufacturing Complexity
(UMC)
Signal Robustness
Interference And Susceptibility
Coexistence
3.1
3.2.2
IMPORTANCE
LEVEL
PROPOSER RESPONSE
B
+
A
+
3.2.3
A
+
Manufacturability
3.3.1
A
+
Time To Market
3.3.2
A
+
Regulatory Impact
3.3.3
A
+
3.4
A
Technical Feasibility
Scalability (i.e. Payload Bit
Rate/Data Throughput,
Channelization – physical or coded,
Complexity, Range, Frequencies of
Operation, Bandwidth of Operation,
Power Consumption)
Location Awareness
CRITERIA
MAC Enhancements And
Modifications
Submission
+
3.5
C
0
REF.
IMPORTANCE
LEVEL
PROPOSER RESPONSE
C
+
4.1.
Slide 41
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Self-evaluation Matrix (2)
CRITERIA
Size And Form Factor
REF.
IMPORTANCE
LEVEL
5.1
PHY-SAP Payload Bit Rate & Data Throughput
Payload Bit Rate
5.2.1
Submission
B
A
PROPOSER RESPONSE
+
+
Packet Overhead
5.2.2
A
+
PHY-SAP Throughput
5.2.3
A
+
Simultaneously Operating
Piconets
Signal Acquisition
5.3
A
5.4
A
+
System Performance
5.5
A
+
Link Budget
5.6
A
+
Sensitivity
5.7
A
+
Power Management Modes
5.8
B
+
Power Consumption
5.9
A
+
Antenna Practicality
5.10
B
+
Slide 42
+
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Convolutional Encoder
 Assume a mother convolutional code of R = 1/3, K = 7. Having a
single mother code simplifies the implementation.
 Generator polynomial: g0 = [1338], g1 = [1458], g2 = [1758].
Output Data A
Input
Data
D
D
D
D
D
D
Output Data B
Output Data C
 Higher rate codes are achieved by puncturing the mother code.
Puncturing patterns are specified in latest revision of 03/268.
Submission
Slide 43
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Bit Interleaver: Mode 1 (3-band)
 Bit interleaving is performed across the bits within an OFDM symbol
and across at most three OFDM symbols.
 Exploits frequency diversity.
 Randomizes any interference  interference looks nearly white.
 Latency is less than 1 ms.
 Bit interleaving is performed in three stages:
 First, 3NCBPS coded bits are grouped together.
 Second, the coded bits are interleaved using a NCBPS3 block symbol
interleaver.
 Third, the output bits from 2nd stage are interleaved using a (NCBPS/10)10
block tone interleaver.
 The end results is that the 3NCBPS coded bits are interleaved across 3
symbols and within each symbol.
 If there are less than 3NCBPS coded bits, which can happen at the end of
the header or near the end of a packet, then the second stage of the
interleaving process is skipped.
Submission
Slide 44
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Bit Interleaver: Mode 1 (3-band)
 Ex: Second stage (symbol interleaver) for a data rate of 110 Mbps
Read In
N CB P S  3
Read Out
x 1 x 2 ... x 300
x 1 x 4 ... x 298 x 2 x 5 ... x 299 x 3 x 6 ... x 300
300 Coded bits = 3 OFDM symbols
300 Coded bits = 3 OFDM symbols
 Ex: Third stage (tone interleaver) for a data rate of 110 Mbps
Read In
Read Out
N CB P S /10  10
y 1 y 11 ... y 91 y 2 y 12 ... y 92 ... y 10 y 20 ... y 100
y 101 y 111 ... y 191 y 102 y 112 ... y 192 y 110 y 120 ... y 200
y 201 y 211 ... y 291 y 202 y 212 ... y 292 y 210 y 220 ... y 300
y 1 y 2 ... y 300
300 Coded bits = 3 OFDM symbols
Submission
300 Coded bits = 3 OFDM symbols
Slide 45
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Frequency Synthesis
 Example: frequency synthesis for a Mode 2 (7-band) device:
Select
SSB
1584 MHz
SSB
6336
MHz
PLL
/3
2112
MHz
/2
1056
MHz
/2
528
MHz
6336
MHz
Sampling
Clock
/2
264
MHz
Desired
Center
Frequency
SSB
264 MHz
792 MHz
Select
SSB
Submission
4224 MHz
SSB
Slide 46
Select
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Multi-band OFDM: RX Architecture
 Block diagram of an example RX architecture:
LPF
VGA
ADC
ADC
sin (2f ct)
Descrambler
Q
VGA
Viterbi
Decoder
LNA
LPF
DeInterleaver
I
FEQ
Remove Pilots
Pre-Select
Filter
Synchronization
Remove CP
FFT
AGC
cos(2f ct)
Carrier
Phase
and
Time
Tracking
 Architecture is similar to that of a conventional and proven
OFDM system. Can leverage existing OFDM solutions for the
development of the Multi-band OFDM physical layer.
Submission
Slide 47
A. Batra, Texas Instruments et al.
Output
Data
July 2003
doc.: IEEE 802.15-03/267r1
Simulation Parameters
 Assumptions:
 System as defined in 03/268.
 Clipping at the DAC (PAR = 9 dB).
 Finite precision ADC (4 bits @ 110/200 Mbps).
 Degradations incorporated:









Submission
Front-end filtering.
Multi-path degradation.
Clipping at the DAC.
Finite precision ADC.
Crystal frequency mismatch (20 ppm @ TX, 20 ppm @ RX).
Channel estimation.
Carrier/timing offset recovery.
Carrier tracking.
Packet acquisition.
Slide 48
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
FFT/IFFT Complexity
 Number of complex multipliers and complex adders needed per clock cycle for a
128 point FFT.
Clock
Complex Multipliers / clock cycle
Complex Adders / clock cycle
102.4 MHz
10
28
128 MHz
8
22.4
1 Finger Rake
ADC
528
MHz
FFT

in terms of
complex multiplies
ADC
1024
MHz

 OFDM efficiently captures multi-path energy with lower complexity!
 128-point FFT is realizable in current CMOS technology.


A technical contribution (03/213) by Roger Bertschmann (SiWorks, Inc.) shows that they
have a 128-point IFFT/FFT core which can be used in a Multi-band OFDM system.
The synthesized core has a gate count of approximately 70K gates in a 130 nm TSMC
process.
Submission
Slide 49
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
System Performance (1)
 PER as a function of distance and data rate in an AWGN and CM2
environment for a Mode 1 DEV: 3-band (90% link success probability).
Submission
Slide 50
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
System Performance (2)
 PER as a function of distance and data rate in an CM3 and CM4
environment for a Mode 1 DEV: 3-band (90% link success probability).
Submission
Slide 51
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Signal Acquisition
 Preamble is transmitted on bands 1–3 and
is designed to work at 3 dB below sensitivity
for 55 Mbps.
 Prob. of false detect (Pf) = 6.2 x 10-4.
 The results for prob. of miss detect (Pm) vs.
distance @ 110 Mb/s was averaged over
500 noise realization for 100 channels in
each channel environment:
 The start of a valid OFDM transmission at a
receiver sensitivity level  -83.5 dBm shall
cause CCA to indicate busy with a
probability > 90% in 4.69 ms.
Submission
Slide 52
A. Batra, Texas Instruments et al.
July 2003
doc.: IEEE 802.15-03/267r1
Half-Rate Pulse Repetition Factor
 It is possible to reduce receiver
power consumption by using a
half-rate pulse repetition factor
scheme (see figure for two
possible options).
 Digital power consumption can
Full Rate (Piconet 1)
Fa Fb Fc Fa Fb Fc Fa Fb Fc Fa Fb Fc
Fa
also be reduced by turning off
some of the analog/RF circuits.
Note that circuits with long time
constants cannot be turned off.
Estimated analog power
savings is between 20–40%.
Submission
Fb
Fc
Fa
Fb
Fc
Time
be reduced by 40–50%.
 Analog power consumption can
Time
Option #1: ½ Rate Sym bol Rate Control (Piconet 1)
Option #2: ½ Rate Hop Fram e Rate Control (Piconet 1)
Fa Fb Fc
Fa Fb Fc
Time
Full Rate (Piconet 2)
Fa Fc Fb Fa Fc Fb Fa Fc Fb Fa Fc Fb
Time
Slide 53
A. Batra, Texas Instruments et al.