1. March 2010
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Harmonization of The 15.4g Mandatory Data Rate Proposal]
Date Submitted: [ 2 March, 2010]
Source: [Khanh Tuan Le] Company [Texas Instruments]
[] Company []
Address [Gaustadalleen 21, 0349 Oslo, Norway]
Voice: [ ],
Re: []
Abstract: [Proposal to use 2-GFSK BT=0.5for 15.4g 50 kbps mandatory data rate. Background and elaboration.]
Purpose: [Technical proposal. Presented to the g SUN Task Group for consideration.]
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
Khanh Tuan Le (TI)

2. Harmonization of The 15.4g Mandatory Data Rate Proposal
March 2010
Harmonization of The 15.4g Mandatory Data Rate Proposal
2nd March 2010
Khanh Tuan Le
Khanh Tuan Le (TI)

3. doc.: IEEE 802.15-<doc#>
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doc.: IEEE <doc#>
March 2010
Background
Ref.: g-candidate-text-comments.xls Comment #324: "The mandatory data rate 50 kbps at the 915 MHz ISM band is specified using FSK while the same mandatory data rate at all other ISM bands is specified using GFSK. Spectrum efficiency and low adjacent channel power are desirable and hence GFSK is a better choice than FSK."
Proposed Change: "Recommend to change FSK to GFSK with BT=0.5. The definition of the mandatory data rate 50 kbps will be unified across all listed ISM bands.“
Achievable Advantages: Harmonization of the 50 kbps mandatory data rate using GFSK modulation format for improved spectral efficiency and better co-existence without any performance, cost or power trade-offs.
Khanh Tuan Le (TI)
<author>, <company>

4. Intention of The Proposed Change
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Intention of The Proposed Change
The intention is to suggest that GFSK is a better modulation format choice than FSK for the IEEE g mandatory data rate of 50 kbps from a technical perspective.
As specifically stated in comment #324, the proposal relates only to the IEEE g mandatory data rate of 50 kbps and not the optional data rates with various modulation definitions.
Khanh Tuan Le (TI)
<author>, <company>

5. AGENDA 15.4g Mandatory Data Rate Performance
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March 2010
AGENDA
15.4g Mandatory Data Rate
Performance
Spectral Efficiency and Co-existence
GFSK Radio Availability and Maturity
Conclusions
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Khanh Tuan Le (TI)
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<author>, <company>

6. 15.4g Mandatory Data Rate Data Rate: 50 kbps - Harmonized.
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15.4g Mandatory Data Rate
Data Rate: kbps Harmonized.
Modulation Index: Harmonized.
Channel Spacing: kHz - Harmonized.
Modulation Format
/ / MHz: GFSK
MHz: FSK
Are there any technical reasons to differentiate the modulation format of the mandatory data rate for different frequency bands?
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Khanh Tuan Le (TI)
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<author>, <company>

7. Performance GFSK and FSK provide the same performance.
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Performance
Transmitter: GFSK and FSK are both constant envelope modulation techniques and can use exactly the same non-linear power-efficient transmitter architectures and circuit designs.
Receiver:
GFSK and FSK based radios will satisfy the receive sensitivity requirement for the 50 kbps mandatory data rate specified by the IEEE g (draft: -90 dBm).
GFSK and FSK with modulation index 1.0 provide the same receive sensitivity without any cost or power differences.
GFSK and FSK provide the same performance.
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Khanh Tuan Le (TI)
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<author>, <company>

8. Theoretical Output Power Spectrum
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Theoretical Output Power Spectrum
Data Rate: 50 kbps
Modulation Index: 1.0
2-FSK
2-GFSK BT=0.5
GFSK is inherently more spectrally efficient than FSK for the same data rate and modulation index.
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Khanh Tuan Le (TI)
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<author>, <company>

9. Spectral Efficiency and Co-Existence
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Spectral Efficiency and Co-Existence
Co-existence in terms of modulation spectral efficiency must be addressed at the PHY level.
GFSK is inherently more spectrally efficient than FSK.
GFSK has a well defined PSD and less power leakage to the neighboring channels than FSK.
ISM bands are unlicensed frequency bands
Co-existence with 15.4g and also other radio devices is important.
Large and rapidly increasing number of deployed devices
Focus on co-existence is and will be increasingly important.
GFSK is better than FSK in terms of co-existence.
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Khanh Tuan Le (TI)
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<author>, <company>

10. Advantages of Gaussian Shaping
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Advantages of Gaussian Shaping
Gaussian shaping, typically done in the digital domain, provides a standardized, well-known and accurate technique to control the signal output spectrum. Output frequency response is independent of the data rate.
Analog filters typically need to be programmed and calibrated based on the data rate. Fixed filter response limits the flexibility and/or results in poor filtering of the output signal.
Standardized Gaussian shaping enables optimal PHY interoperability.
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Khanh Tuan Le (TI)
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<author>, <company>

11. Spectrum Utilization <month year> doc.: IEEE 802.15-<doc#>
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Spectrum Utilization
Data Rate: 50 kbps
Modulation Index: 1.0
2-GFSK BT=0.5
Channel Spacing: 200 kHz
Unwanted signal power leaked into
neighboring channels can result in:
Higher power consumption (more signal power required for the same SNR)
Higher selectivity requirements (more filtering), i.e. higher complexity and more power hungry radios
Data Rate: 50 kbps
Modulation Index: 1.0
2-FSK
Channel Spacing: 200 kHz
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Khanh Tuan Le (TI)
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<author>, <company>

12. Mandatory Data Rate Harmonization
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Mandatory Data Rate Harmonization
Harmonization of the 50 kbps mandatory data rate across all applicable frequency bands can be achieved. The mandatory data rate for Japan, Europe, China already employs GFSK.
GFSK provides the best and harmonized modulation format choice for the mandatory data rate, i.e. the same performance and superior co-existence qualities compared to FSK.
There seem to be no technical reasons to differentiate the modulation format of the mandatory data rate for different frequency bands.
Data Rate: kbps Harmonized.
Modulation Index: Harmonized.
Channel Spacing: kHz - Harmonized.
Modulation Format: GFSK Harmonized (*Proposal)
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Khanh Tuan Le (TI)
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<author>, <company>

13. GFSK Radio Availability and Maturity
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GFSK Radio Availability and Maturity
Simple, low-cost and low-power GFSK radios are readily available. Off-the-shelf radio transceivers today support both GFSK and FSK without any cost or power penalties.
GFSK radios are highly flexible (programmable) and can effectively support the 15.4g mandatory data rate and optional data rates.
GFSK has been widely used for AMR/AMI applications, including ultra-low power metering systems.
New standards seem to favor GFSK, not FSK, for better utilization of the spectrum.
Well-known standards using GFSK
IEEE (Bluetooth)
IEEE d - ratified in 2009, newest 15.4 PHY amendment
All submitted 15.4g proposals include GFSK
GFSK is considered as a proven and future-proof technology.
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<author>, <company>

14. Proposed Change Summary
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Proposed Change Summary
FSK
GFSK
Proven In The Field 
Good Sensitivity
Power Efficient Transmitters
Excellent Range
Low Complexity & Low Power
Availability
Spectral Efficiency and Co-Existence Friendly
 
Future-Proof
Harmonization of The Mandatory Data Rate
Conclusion: GFSK is the best technical choice for the harmonized 15.4g mandatory data rate without any performance, cost or power compromises!
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Khanh Tuan Le (TI)
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<author>, <company>

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March 2010
Conclusions
GFSK and FSK provide the same performance for the mandatory data rate.
GFSK is inherently more spectrally efficient than FSK.
GFSK is inherently better than FSK in terms of co-existence.
There are no technical reasons to differentiate the modulation format of the mandatory data rate for different frequency bands.
Harmonization of the mandatory data rate can be achieved by choosing GFSK as the modulation format.
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<author>, <company>

16. Thank you! <month year> doc.: IEEE 802.15-<doc#>
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Thank you!
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