Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Modulation and Coding Scheme for 802.15.3a] Date Submitted: [3 March, 2003] Source: [Francois Chin, Madhukumar, Xiaoming Peng, Sivanand] Company [Institiute for Infocomm Reseaerch (Singapore)] Address [] Voice:[], FAX: [], E-Mail:[chinfrancois@i2r.a-star.edu.sg] Abstract: [] Purpose: [Provide background information and analysis regarding how 802.15.3 modulation and coding schemes can be employed and how they perform in UWB channels] 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. Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

2. Outline • Proposed use of UWB band • Proposed Modulation and Coding Scheme • System performance Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

3. Proposed use of UWB band • Proposed Plan for Operating Frequency Bands • 15 frequency sub-bands (500MHz each) within 3.1 – 10.6 GHz bands • Centre frequency of sub- bands = 3.35 + (k-1)*0.5 GHz • Merits • Different frequency channels (consisting disjoint set of sub-bands) are allocated to simultaneous operating piconets • Adjacent channel (consisting disjoint set of sub-bands) interference is suppressed to certain extend by receiver sub-band circuitry • Coexistence with IEEE 802.11a is ensured as sub-bands centred at 5.35GHz or 5.85 GHz can be avoided, leaving others for 4 simultaneous operating piconets Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

4. Frequency sub-band scanning • When a device is scanning to start a piconet, it should scan 15 frequency sub-bands (500MHz each) within 3.1 – 10.6 GHz to reduce the probability of selecting a occupied sub-band • The device should rate the sub-bands based on an estimate of the amount of traffic and the power level in each sub-band • The device then chooses those sub-bands that has traffic or/and power levels that is below a specific threshold Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

5. Key features of PHY proposal • Modulation format and coding schemes • As proposed in 802.15.3 – device shall, at a minimum, support QPSK modulation • QPSK & QAM modulator – to produce baseband signal that will excite the transmit circuitry to launch a pulse in one of the proposed frequency sub-band • Fast switching reference PLL, switching at Pulse Repetition Frequency (PRF), together with quadrature mixer for frequency translation, to translate each pulse to and from its designated frequency sub-band • Multiple PRFs are chosen to allow ‘grading’ of devices and to avoid intersymbol interference Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

6. Transmit Signals PRF = 250 MHz • Consecutive pulses are transmitted over different sub-bands at a rate of PRF f0 f1 f2 f3 f4 f5 f6 f7 Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

7. Proposed Modulation, Coding, PRF, Payload Bit Rates & Data Throughput Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

8. PRF / Symbol Transmission Rate • Multiple Pulse Repetition Frequencies (62.5/125/250 MHz) provides scalability to • Power consumption • Payload bit rate • PHY-SAP data throughput • Low target PHY-SAP data throughput, payload bit rate and low basic bit rate (for preamble, PHY/MAC header) that is associated to low PRF ensures low power consumption level • If a device supports a PRF, it should also support all lower PRF • PRF should remains within a frame transmission Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

9. Base Modulation Scheme & Basic Bit Rate • Uncoded DQPSK is used as the base modulation scheme for Preamble, PHY header and MAC header Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

10. PHY Frame Format • Almost identical to that in 802.15.3 802.15.3 - 11 Mbps Mode 802.15.3 - 22 Mbps Mode 802.15.3 - 33 Mbps Mode 802.15.3 - 44 Mbps Mode 802.15.3 - 55 Mbps Mode Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

11. Multiple Bit Stream Encoder or Single Bit Stream Encoder? Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

12. Multiple Bit Stream Encoder or Single Bit Stream Encoder? • Single bit stream encoder should be chosen as it can better correct uniformly-spaced symbol errors due to ‘poor’ performance in particular sub-band Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

13. PHY-SAP Payload Bit Rate & Data Throughput Packet overhead parameters for data throughput comparison Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

14. PHY-SAP Payload Bit Rate & Data Throughput for 62.5 MHz PRF Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

15. PHY-SAP Payload Bit Rate & Data Throughput for 125 MHz PRF Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

16. PHY-SAP Payload Bit Rate & Data Throughput for 250 MHz PRF Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

17. System Performance Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

18. Sub-band Receiver • Each device should have same number of parallel subband receivers as number of sub-bands employed • Each sub-band receiver oversamples at 500MHz and combines the oversamples with RAKE or channel equalisers Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

19. Eb/No in AWGN & UWB Channel in OverSampling RAKE Receiver Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

20. Channel Energy Loss in diff. CMs • Due to staggered frequency-time transmission, energy outside receive timing window (of duration equals to 1/PRF) of the current sub-band is lost Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

21. Gain Control Antenna Quad. Mixer LPF BPF I LNA VGA -90° LPF Q LO RF Receiver Noise Figure With fast switching PLL Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

22. Link Budget for 62.5 MHz PRF Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

23. Link Budget for 125MHz PRF Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

24. Link Budget for 250 MHz PRF Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

25. PRF and simultaneously operating piconets • 1/PRF * (total #sub-bands per piconet) should be more than Channel delay spread so that a simple RAKE (vector RAKE) can be used • Normally, when a another piconet get associated, operating PRF is reduced too (Data throughput is reduced alongside) to maintain PER performance Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

26. RAKE or Channel Equaliser? • Adaptive Equaliser, on the other hand, can be employed to equalise ISI in the event of simultaneously operating piconets, when the total sub-band per piconet reduces. • This will generally result in maintaining the data throughput, as Eb/No is maintained • This implies, when a another piconet get associated, operating PRF can be retained (Data throughput remains alongside), while PER performance is maintained Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

27. Merits of Proposed Modulation and Coding Schemes for Alt-PHY • 802.15.3 Modulation and coding schemes are • Of low complexity • Well proven and mature technology • Free of proprietary or patented IP Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R

28. Merits of Proposed Alt-PHY Francois Chin, Madhukumar, Xiaoming Peng, Sivanand, I2R