March 2003 Anuj Batra et al., Texas Instrumen ts Slide 1 doc.: IEEE 802.15- 03/141r1 Submiss ion Project: IEEE P802.15 Working Group for Wireless Personal Area Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Networks (WPANs) Submission Title: [TI Physical Layer Proposal] Date Submitted: [03 March, 2003] Source: [Anuj Batra, Jaiganesh Balakrishnan, Anand Dabak, et al. ] Company [Texas Instruments] Address [12500 TI Blvd, MS 8649, Dallas, TX 75243 ] Voice:[214-480-4220], FAX: [972-761-6966], E-Mail:[[email protected]] 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 TI physical layer 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
Transcript
March 2003
Anuj Batra et al., Texas InstrumentsSlide 1
doc.: IEEE 802.15-03/141r1
Submission
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Address [12500 TI Blvd, MS 8649, Dallas, TX 75243]Voice:[214-480-4220], FAX: [972-761-6966], E-Mail:[[email protected]]
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 TI physical layer 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.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 2
doc.: IEEE 802.15-03/141r1
Submission
TI Physical Layer Proposal:Time-Frequency Interleaved OFDM
Anuj Batra, Jaiganesh Balakrishnan, Anand DabakRanjit Gharpurey, Paul Fontaine, Jerry LinJin-Meng Ho, Simon Lee, Michel Frechette
Steven March, Hirohisa Yamaguchi
Texas Instruments12500 TI Blvd, MS 8649
Dallas, TX
March 3, 2003
March 2003
Anuj Batra et al., Texas InstrumentsSlide 3
doc.: IEEE 802.15-03/141r1
Submission
Outline
Examine the trade-offs in the design of a UWB system: Choice of operating bandwidth Spreading gain vs. Pulse repetition frequency (PRF)
Overview of Time-Frequency Interleaved OFDM (TFI-OFDM)
Performance results for the TFI-OFDM system
Selected responses to the selection criteria
Advantages of the TFI-OFDM system
Summary
March 2003
Anuj Batra et al., Texas InstrumentsSlide 4
doc.: IEEE 802.15-03/141r1
Submission
Trade-offs in Designing a UWB system:
- Choice of Operating Bandwidth
- Spreading Gain vs. PRF
March 2003
Anuj Batra et al., Texas InstrumentsSlide 5
doc.: IEEE 802.15-03/141r1
Submission
What Operating BW to Use?
Goals to keep in mind when selecting the operating BW: Early time to market: want to enable UWB technology ASAP. CMOS friendly solutions: want solutions that can be integrated. Low cost: enable adoption of technology in portable CE devices. U-NII interference robustness: 802.11a is the incumbent device. World-wide compliance: one solution that is flexible enough to
work worldwide. Antenna/filter design: want to be able to use off-the-shelf
components.
We now examine the various trade-offs in choosing the operating BW. We want to select the operating BW in such a way as to achieve all of these goals.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 6
doc.: IEEE 802.15-03/141r1
Submission
Small Gains by Increasing BW (1)
Assume that the TX signal occupies the BW from fL to fU. Assume that fL is fixed at 3.1 GHz. Vary upper frequency fU between 4.8 GHz and 10.6 GHz. Assume that the transmit spectrum is flat over entire BW. TX power = 41.25 dBm + 10log10(fU – fL).
802.15.3a has specified a free-space propagation model:
fg is the Geometric mean of lower/upper frequencies (10-dB points) d is the UWB transmitter-receiver separation distance (assume d = 10 m) c is the speed of light
Look at Received Power = TX Power Path Loss, as a function of upper frequency.
(dB) 4
log20)( 10
c
dfdP
gL
March 2003
Anuj Batra et al., Texas InstrumentsSlide 7
doc.: IEEE 802.15-03/141r1
Submission
Small Gains From Increasing BW (2)
Increasing the upper frequency to 7.0 GHz (10.5 GHz) gives at most a 2.0 dB (3.0 dB) advantage in total received power.
On the other hand, increasing the upper frequency, results in an increased noise figure: For fu = 7.0 GHz, by at least 1.0 dB. For fu = 10.5 GHz, by at least 2.0 dB.
Result: using frequencies larger than 4.8 GHz increases the overall link margin by at most 1.0 dB with the current RF technology, but at the cost of higher complexity and higher power consumption.
Conclusion: only incremental gains in the link budget can be realized by using frequencies above 4.8 GHz.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 8
doc.: IEEE 802.15-03/141r1
Submission
Optimal Operating Bandwidth
Start with the frequency band from 3.1 to 4.8 GHz: Simplifies the front-end design: LNA and mixers (CMOS friendly). Can use higher precision, lower sampling rate ADCs. Capturing multi-path energy is easier. U-NII rejection is simplified.
Quicker time to market!
As the RF technology improves, start using the higher band as well.
3.1 GHz 10.6 GHz4.8 GHz 5.9 GHz
Start with this band
Use this band in the future as technology improves
U-NII band:802.11a
March 2003
Anuj Batra et al., Texas InstrumentsSlide 9
doc.: IEEE 802.15-03/141r1
Submission
Spreading vs. PRF
A full-band system obtains its processing gain by spreading (high PRF) the signal across the entire UWB bandwidth.
A sub-band system obtains its processing gain by using a lower pulse repetition frequency (PRF) in each of the sub-bands.
Basic idea is to use OFDM over the entire BW: Start with frequencies from 3168 MHz to 5280 MHz.
Total of 512 tones, where each tone has a bandwidth of 4.125 MHz. Use different subsets of frequency tones from one OFDM symbol to the
next. Equivalent to interleaving OFDM symbols across time and across
frequency.
3168MHz
3696MHz
4224MHz
4752MHz
Channel#1
Channel#2
Channel#3
5280MHz
5808MHz
6336MHz
6864MHz
7392MHz
7920MHz
8448MHz
8976MHz
9504MHz
10032MHz
10560MHz
Use the fi rst 3 bands to start withf or quick time to market, and f orlow cost and low power solutions.
Use these band in the f uture as the RFtechnology improves. (May or may not use thechannels corresponding to the U-NI I band).Baseband technology remains unchanged.
U-NI IBand
March 2003
Anuj Batra et al., Texas InstrumentsSlide 12
doc.: IEEE 802.15-03/141r1
Submission
Simplified TFI-OFDM
The implementation of TFI-OFDM can be simplified by introducing a small guard interval (9.5 ns) between the OFDM symbols.
The simplified TFI-OFDM system can now be implemented using a single TX/RX chain, 128-point IFFT/FFT, and low rate DACs/ADCs.
time
f req(MHz)
3168
3696
4752
4224312.5 ns
9.5 ns Guard I nterval f orTX/ RX Switching
Time
60.6 ns CyclicPrefi x
Period = 937.5 ns
242.4 ns
March 2003
Anuj Batra et al., Texas InstrumentsSlide 13
doc.: IEEE 802.15-03/141r1
Submission
Alternative Views of TFI-OFDM
Full-band interpretation of TFI-OFDM: TFI-OFDM can be interpreted as a full-band OFDM system using a 512-point IFFT/FFT.
Sub-band interpretation of TFI-OFDM: TFI-OFDM can also be interpreted as a sub-band OFDM system using a 128-point IFFT/FFT on each of the sub-channels.
Because TFI-OFDM can be viewed as both a full-band and a sub-band approach, it inherits strengths from both types of systems.
We choose to view TFI-OFDM in terms of the second approach, because it leads to a much lower complexity solution and can be realized in today’s CMOS technology.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 14
doc.: IEEE 802.15-03/141r1
Submission
Details of the TFI-OFDM System
*More details about the TFI-OFDM system can be found in the latest version of 03/142.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 15
doc.: IEEE 802.15-03/141r1
Submission
TFI-OFDM: Example TX Architecture
Block diagram of an example TX architecture:
Architecture is similar to that of a conventional and proven OFDM system. Can leverage existing OFDM solutions for the development of the TFI-OFDM physical layer.
For a given superframe, the interleaving pattern is specified in the beacon by the PNC. The interleaving pattern is rotated across multiple superframes to mitigate multi-piconet interference.
DACScramblerConvolutional
EncoderPuncturer
BitInterleaver
ConstellationMapping
IFFTInsert Pilots
Add CP & GI
Interleaving Kernel
exp(j2fct)
InputData
March 2003
Anuj Batra et al., Texas InstrumentsSlide 16
doc.: IEEE 802.15-03/141r1
Submission
TFI-OFDM System Parameters
System parameters for rates specifically mentioned in selection criteria document:
Info. Data Rate 110 Mbps 200 Mbps 480 Mbps
Modulation/Constellation
OFDM/QPSK OFDM/QPSK OFDM/QPSK
FFT Size 128 128 128
Coding Rate (K=7) R = 11/32 R = 5/8 R = 3/4
Spreading Rate 2 2 1
Information Tones 50 50 100
Data Tones 100 100 100
Info. Length 242.4 ns 242.4 ns 242.4 ns
Cyclic Prefix 60.6 ns 60.6 ns 60.6 ns
Guard Interval 9.5 ns 9.5 ns 9.5 ns
Symbol Length 312.5 ns 312.5 ns 312.5 ns
Channel Bit Rate 640 Mbps 640 Mbps 640 Mbps
Frequency Band 3168 – 4752 MHz 3168 – 4752 MHz 3168 – 4752 MHz
Multi-path Tolerance 60.6 ns 60.6 ns 60.6 ns
March 2003
Anuj Batra et al., Texas InstrumentsSlide 17
doc.: IEEE 802.15-03/141r1
Submission
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.
For rates > 200 Mb/s, need to implement full “I/Q” transmitter.
DACScramblerConvolutional
EncoderPuncturer
BitInterleaver
ConstellationMapping
IFFTInsert Pilots
Add CP & GI
Interleaving Kernel
cos(2fct)
InputData
March 2003
Anuj Batra et al., Texas InstrumentsSlide 18
doc.: IEEE 802.15-03/141r1
Submission
OFDM Parameters
Transmit information using a set of contiguous orthogonal carriers that occupies a bandwidth greater than 500 MHz at all times, according to the FCC requirement: Carriers are efficiently generated using a 128-point IFFT. Use 100 tones for data (QPSK modulation). Use 12 tones for standard pilots. Use 10 tones for user-defined pilots (used to meet 500 MHz BW
requirement). Remaining 6 orthogonal tones are NULL (zero).
Sub-carrier frequency spacing = 4.125 MHz.
Cyclic prefix length = 32 samples (60.6 ns).
Guard interval length = 5 samples (9.5) – time used for switching.
Total OFDM symbol length = 165 samples (312.5 ns).
March 2003
Anuj Batra et al., Texas InstrumentsSlide 19
doc.: IEEE 802.15-03/141r1
Submission
Convolutional Encoder and Bit Interleaver
Assume a mother convolutional code of R = 1/3, K = 7. Having a single mother code simplifies the implementation.
Higher rate codes are achieved by puncturing the mother code.
Bit interleaving is performed across bits within an OFDM symbol and across at most three OFDM symbols. Exploits frequency diversity and randomizes any interference.
D D D D D DI nputData
Output Data A
Output Data B
Output Data C
March 2003
Anuj Batra et al., Texas InstrumentsSlide 20
doc.: IEEE 802.15-03/141r1
Submission
Channelization
The relationship between fc and channel number nch is
Initially, only the first 3 channels will be defined.
More channels can be added as RF technology improves.
CHNL_ID (nch) Center Frequency (fc)
1 3432 MHz
2 3960 MHz
3 4488 MHz
(MHz) 5282904)( chchc nnf
March 2003
Anuj Batra et al., Texas InstrumentsSlide 21
doc.: IEEE 802.15-03/141r1
Submission
TFI-OFDM: PLCP Frame Format
PLCP frame format:
Rates supported: 55, 80, 110, 160, 200, 320, 480 Mb/s. Support for 55, 110, and 200 Mb/s is mandatory.
Preamble length = 9.38 s. Burst preamble length = 4.69 s. For the sake of robustness, the PLCP header, MAC header, HCS, and
tail bits are always sent at the information data rate of 55 Mb/s. PLCP header + MAC header + HCS + tail bits = 2.19 s. Maximum frame payload supported is 4095 bytes.
PLCP Preamble30 OFDM symbols
PHYHeader
MACHeader
HCSFrame Payload
Variable Length: 0 4095 bytesPadBits
TailBits
11.5625 s
55 Mb/s 55, 80, 110, 160, 200, 320, 480 Mb/s
RATE3 bits
Reserved1 bit
LENGTH12 bits
Scrambler Init2 bits
TailBits
FCS
March 2003
Anuj Batra et al., Texas InstrumentsSlide 22
doc.: IEEE 802.15-03/141r1
Submission
Link Budget and Receiver Sensitivity
Assumption: AWGN and 0 dBi gain at TX and RX antennas.
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
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 3.0 dB 3.0 dB 3.0 dB
Link Margin 5.5 dB 10.2 dB 12.2 dB
RX Sensitivity Level -80.0 dBm -76.7 dBm -72.7 dB
March 2003
Anuj Batra et al., Texas InstrumentsSlide 23
doc.: IEEE 802.15-03/141r1
Submission
System Performance (1)
PER as a function of distance and information data rate in an AWGN and CM2 environment*.
* Results obtained using old channel model.All results incorporate shadowing.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 24
doc.: IEEE 802.15-03/141r1
Submission
System Performance (2)
PER as a function of distance and information data rate in an CM3 and CM4 environment*.
* Results obtained using old channel model.All results incorporate shadowing.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 25
doc.: IEEE 802.15-03/141r1
Submission
System Performance (3)
The distance at which the TFI-OFDM system can achieve a PER of 8 % for a 90% link success probability is tabulated below**:
* Includes losses due to front-end filtering, ADC degradation, multi-path degradation, channel estimation, carrier tracking, packet acquisition, etc.
Range* AWGN CM1 CM2 CM3 CM4
110 Mbps 19.1 m N/A 9.8 m 9.7 m 8.8 m
200 Mbps 13.5m N/A 6.3 m 5.8 m 5 m
480 Mbps 8.7 m 2 m 2 m N/A N/A
** Results obtained using old channel model.All results incorporate shadowing.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 26
doc.: IEEE 802.15-03/141r1
Submission
Simultaneously Operating Piconets
Assumptions: Received signal is 6 dB above sensitivity dref = 9.55 meters
Single co-channel interferer separation distance as a function of the reference and interfering multipath channel environments.
Test Link/Interferer CM1 CM2 CM3 CM4
CM1 12.6 m 13.0 m 12.3 m 12.4 m
CM3 13.0 m 12.3 m 12.2 m 12.5 m
CM4 13.8 m 12.7 m 12.2 m 12.7 m
All results incorporate shadowing.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 27
doc.: IEEE 802.15-03/141r1
Submission
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.
Coexistence with 802.11a/b and Bluetooth is relatively straightforward because these bands are completely avoided.
Interferer Value
IEEE 802.11b @ 2.4 GHz dint = 0.3 meter
IEEE 802.11a @ 5.3 GHz dint = 0.3 meter
Modulated interferer SIR -3.8 dB
Tone interferer SIR -4.8 dB
March 2003
Anuj Batra et al., Texas InstrumentsSlide 28
doc.: IEEE 802.15-03/141r1
Submission
PHY-SAP Throughput
Assumptions: MPDU (MAC frame body + FCS) length is 1024 bytes. SIFS = 10 s. MIFS = 2 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 85.1 Mb/s 130.4 Mb/s 211.4 Mb/s
5 95.2 Mb/s 155.6 Mb/s 286.4 Mb/s
Number of frames
Throughput @ 110 Mb/s
Throughput @ 200 Mb/s
Throughput @ 480 Mb/s
1 102.3 Mb/s 175.9 Mb/s 362.4 Mb/s
5 105.7 Mb/s 186.3 Mb/s 409.2 Mb/s
March 2003
Anuj Batra et al., Texas InstrumentsSlide 29
doc.: IEEE 802.15-03/141r1
Submission
Complexity
Unit manufacturing cost (selected information): Process: CMOS 90 nm technology node in 2005. Analog section: die size of 2.7 mm2. Digital section: 295K gates, die size of 1.5
mm2.
Power consumption:
Manufacturability: Leveraging standard CMOS technology results in a straightforward development effort. OFDM solutions are mature and have been demonstrated in 802.11a/g solutions, which are currently shipping.
Time to market: the earliest a complete CMOS PHY solution would be ready for integration is 2005.
Size: Solutions for PC card, compact flash, memory stick, SD memory in 2005.
Rate TX RX Deep Sleep
110 Mb/s 93 mW 142 mW 15 W
200 Mb/s 93 mW 156 mW 15 W
March 2003
Anuj Batra et al., Texas InstrumentsSlide 30
doc.: IEEE 802.15-03/141r1
Submission
FFT/IFFT Complexity Calculate the number of complex multipliers and complex adders needed
per clock cycle for a 128 point FFT/IFFT.
Actual gate count will be dependent upon the process and the architecture.
15 complex multiplications @ 99 MHz to a 3-tap RAKE @ 495 MHz
OFDM combines the multi-path energy efficiently with reduced complexity!
128-point FFT/IFFT is realizable in current CMOS technology.
Additional reference: Pok et al. “Chip Design for Monobit Receiver”, IEEE Transactions of Microwave Theory and Techniques, vol. 45, no. 12, December 1997.
Clock Complex Multipliers / clock cycle
Complex Adders / clock cycle
66 MHz 20 56
99 MHz 15 42
132 MHz 10 28
165 MHz 8 23
March 2003
Anuj Batra et al., Texas InstrumentsSlide 31
doc.: IEEE 802.15-03/141r1
Submission
MAC Enhancements
Add a time-frequency interleaving information element (TFI IE) to the beacon: TFI IE contains parameters for synchronizing DEVs using TFI-OFDM PHY. IE payload contains Interleaving Sequence (IS) and Rotation Sequence (RS)
parameters.
IS field specifies the current pattern for interleaving over the channels. RS field specifies the current rotation pattern for the interleaving sequences.
PNC updates the IS parameter in the beacon for each superframe according to the RS parameter. DEVs that miss the beacon can determine the IS based on the definition of the RS
in the last beacon received.
PNC may change the RS parameter by applying the piconet parameter change procedure specified in the IEEE 802.15.3 draft standard. Reuse “New Channel Index” as “New Channel Index/RS Number”.
Octets: 1 1 1 1
Interleaving Sequence Rotation SequenceElement ID Length
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 off-the-shelf components).
Early time to market!
Low cost, low power, and CMOS integrated solution leads to:
Early market adoption!
March 2003
Anuj Batra et al., Texas InstrumentsSlide 34
doc.: IEEE 802.15-03/141r1
Submission
TFI-OFDMAdvantages (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: Channels and tones can be dynamically turned on/off to comply
with changing regulations.
Coexistence with current and future systems: Channels and tones can be dynamically turned on/off for enhanced
coexistence with the other devices.
Scalability: More channels can be added as the RF technology improves. Digital section complexity/power scales with improvements in
technology nodes (Moore’s Law).
March 2003
Anuj Batra et al., Texas InstrumentsSlide 35
doc.: IEEE 802.15-03/141r1
Submission
Summary
The proposed system is specifically designed to be a low power, low complexity CMOS solution.
Expected range for 110 Mb/s: 19.1 meters in AWGN, and nearly 10 meters in multipath environments.
Expected power consumption for 110 Mb/s: 93 mW (TX), 142 mW (RX), 15 W (deep sleep)
TFI-OFDM is coexistence friendly and complies with world-wide regulations.
PHY solution are expected to be ready for integration in 2005.
TFI-OFDM offers the best trade-off between the various system parameters.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 36
doc.: IEEE 802.15-03/141r1
Submission
Backup slides
March 2003
Anuj Batra et al., Texas InstrumentsSlide 37
doc.: IEEE 802.15-03/141r1
Submission
TFI-OFDM: Example RX Architecture
Block diagram of an example RX architecture:
Architecture is similar to that of a conventional and proven OFDM system. Can leverage existing OFDM solutions for the development of the TFI-OFDM physical layer.
Pre-SelectFilter
LNA
sin(2fct)
cos(2fct)
Syn
chro
niza
tion
Rem
ove
CP
FFT
FEQ
Rem
ove
Pilo
ts
Vit
erbi
Dec
oder
De-
scra
mble
r
AGC
CarrierPhaseand
TimeTracking
De-
Inte
rlea
ver
I
Q
LPF
LPF
VGA
VGA
ADC
ADC
OutputData
March 2003
Anuj Batra et al., Texas InstrumentsSlide 38
doc.: IEEE 802.15-03/141r1
Submission
Signal Acquisition
Preamble was designed to be robust and work at 3 dB below sensitivity for 55 Mbps.
The start of a valid OFDM transmission at a receiver sensitivity level -83 dBm shall cause CCA to indicate busy with a prob. > 90% in 4.69 s.
Channel Environment
Probability of miss detect
Pm @ 110 Mb/s
Probability of false alarm
Pf
Acquisition Time
AWGN < 2 10-5 7.2 10-4 < 4.69 s
CM1 < 2 10-5 7.2 10-4 < 4.69 s
CM2 < 2 10-5 7.2 10-4 < 4.69 s
CM3 < 2 10-5 7.2 10-4 < 4.69 s
CM4 < 2 10-5 7.2 10-4 < 4.69 s
March 2003
Anuj Batra et al., Texas InstrumentsSlide 39
doc.: IEEE 802.15-03/141r1
Submission
Is Cyclic Prefix (CP) Sufficient?
For a data rate of 110 Mb/s, studied effect of CP length on performance.
Curves were averaged over 100 realizations of CM3.
For a CP length of 60 ns, the average loss in collected multi-path energy is approx. 0.1 dB.
Inter-carrier interference (ICI) due to multi-path outside the CP is approximately 24 dB below the signal.
March 2003
Anuj Batra et al., Texas InstrumentsSlide 40
doc.: IEEE 802.15-03/141r1
Submission
Peak-to-Average Ratio (PAR) for TFI-OFDM
Average TX Power = –9.5 dBm (this value includes pilot tones)
PAR of 9 dB results in: Impact of clipping at TX DAC is
negligible. Results in a performance loss of
less than 0.1 dB in AWGN. Results in a performance loss of
