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

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [MPSK Modulation for PHY Layer Proposal for Chinese Band] Date Submitted: [30−Aug−2007]

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

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [MPSK Modulation for PHY Layer Proposal for Chinese Band] Date Submitted: [30−Aug−2007] Source: [Liang Li, ChenYang Yang T.T. Liu, Pei Liu, Dixon Paul] Company: [Vinno Technologies Inc, BUAA, Hisilicon Inc. ] Address: [Suite 402, Building D, No.2 Shangdi Xinxi Lu, Beijing 100085, China] Voice:[8610-82782373], FAX: [8610-82893004] E−Mail: [liangli@vinnotech.com, cyyangbuaa@vip.sina.com] Re: [802.15.4c] Abstract: [ ] Purpose: [To encourage discussion in 802.15.4c] 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. Liang Li (Vinno), C.Y. Yang (BUAA)

  2. Proposal • A new PHY Proposal for low-rate WPAN that employs the MSPK modulation scheme with new DSSS sequences: • The MPSK tech is adopted as the basic modulation of communication in LR-WPAN at 780mhz New DSSS sequences: 16 sequences for 4-bit mapping. • Data rate =250Kbps. • Channel separation = 2MHz. • The 1st null-null bandwidth = 750KHz. Liang Li (Vinno), C.Y. Yang (BUAA)

  3. The Important Operation Coefficients Fc=780, 782, 784, 786 MHz The Transmit Path (I or Q Paths) Liang Li (Vinno), C.Y. Yang (BUAA)

  4. DSSS Mapping (Symbol to Chips) • The Direct Sequence Spread Spectrum (DSSS) tech is applied • 16 orthogonal spreading sequences are designed to map 4 information bits. The base sequence is a 16 length chirp sequence and the other 15 sequences are its cyclic shifts. Liang Li (Vinno), C.Y. Yang (BUAA)

  5. Pre-Processing • Remove DC component The DC components of one base sequence is • Subtract ADC from each chip directly in the processing, all DC components of PPDU can be mitigated. Liang Li (Vinno), C.Y. Yang (BUAA)

  6. Proposal for preamble • SFD Processing • ---- The SFD sequence is the conjugate of the Preamble sequence The Phase sequence of SFD is: The Phase sequence of Preamble is: Liang Li (Vinno), C.Y. Yang (BUAA)

  7. 0 1 0.8 -10 0.6 -20 Pluse Shape 0.4 PSD (dB) -30 0.2 -40 0 -50 -0.2 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 -60 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 t [Tc] f [MHz] Pulse Shaping Filter The Pulse Shaping Filter on I and Q path is Raise-Cosine ( t=0.5 ): Liang Li (Vinno), C.Y. Yang (BUAA)

  8. Modulation MPSK Liang Li (Vinno), C.Y. Yang (BUAA)

  9. Proposal for preamble The preamble field proposed here consists of at least 4octets, which is same as ones of OQPSK at 915MHz of IEEE 802.15.4-2006 Liang Li (Vinno), C.Y. Yang (BUAA)

  10. 1 0.5 Real 0 20 -0.5 10 -1 0 2 4 6 8 10 12 14 16 0 t / Tc -10 1 PSD 0.5 -20 Imag 0 -30 -0.5 -1 -40 0 2 4 6 8 10 12 14 16 t / Tc -50 -60 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 f/MHz Promoted Communication Tech in LR-WPAN(4) • The Transmit waveforms (I and Q) and Spectrum are: • ( Condition: RC shaping filter, Random chip sequence, 100 kHz resolution band width, 0 dBm TX-power ) Liang Li (Vinno), C.Y. Yang (BUAA)

  11. PSD in the Band • PSD requirements in Band • Minimum Receiver Jamming Resistance Requirement Liang Li (Vinno), C.Y. Yang (BUAA)

  12. 1.5 1 0.5 Imag Rart 0 -0.5 -1 -1.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 Real Part EVM, Crest fractor and Constellation Chart MPSK Constellation Chart (Nyquist sampling points) Constellation chart (RC-pulse shaping): Liang Li (Vinno), C.Y. Yang (BUAA)

  13. 0 10 -1 10 -2 10 -3 Sync Error Rate 10 -4 10 -5 10 -6 10 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 E /n b 0 Performance: Synchronization Performance Simulation Condition: In AWGN channel, ideal synchronization, 20 data octets in each packet, sync algorithm is sliding correlation. Liang Li (Vinno), C.Y. Yang (BUAA)

  14. 0 10 -1 10 -2 PER 10 -3 10 -4 10 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 E /n b 0 Performance: Demodulation Performance Simulation Condition: In AWGN channel, ideal synchronization, Correlation demodulation, 20 data octets in each packet Liang Li (Vinno), C.Y. Yang (BUAA)

  15. 0 10 AWGN +/-20ppm +/-40ppm +/-80ppm -1 10 +/-120ppm -2 PER 10 -3 10 -4 10 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 E /n b 0 Performance: Performance under sync and freq-offset Simulation Condition: In AWGN channel, with sync and freq-offset Estimation, 20 data octets in each packet Liang Li (Vinno), C.Y. Yang (BUAA)

  16. Performance in Multipath Channel (1) • Tapped-Delay-Line Channel Model • IEEE P802.15 Working Group for WPANs, Multipath Simulation Models for Sub-GHz PHY Evaluation, 15-04-0585-00-004b, Oct. 2004. • Power delay profile is exponentially declined. • Each path is independently Rayleigh fading. • The average power of the channel response over many packets is 1, but in each packet the power is varied. • Short Delay Environments • Without rake receiver • Long Delay Environments • With 3-tap rake receiver Liang Li (Vinno), C.Y. Yang (BUAA)

  17. Performance in Multipath Channel (2) • Test Conditions • RMS delay spread 0~250ns • Tx nonlinear amplifier, Rapp’s model, p=3, backoff=1.5dB • Tx and Rx frequency offset ±80ppm, phase noise -110dBc/Hz @±1MHz • Tx and Rx IQ imbalance 2dB, 10o • 3bit AD sampling, 8bit baseband processing • Rx will implement time and frequency synchronization and data detection • 5000 packets are tested for each SNR, each packet comprises 20 octets • The packet error rate is counted for 90% coverage Liang Li (Vinno), C.Y. Yang (BUAA)

  18. 0.5 0 ns 0.45 50 ns 100 ns 0.4 250 ns 0.35 0.3 0.25 PER 0.2 0.15 0.1 0.05 0 10 11 12 13 14 15 16 17 18 19 20 E /N (dB) b 0 PER in Short Delay Environments without Rake Receiver Liang Li (Vinno), C.Y. Yang (BUAA)

  19. 0.5 0 ns 0.45 100 ns 200 ns 0.4 300 ns 400 ns 0.35 500 ns 600 ns 0.3 0.25 PER 0.2 0.15 0.1 0.05 0 10 11 12 13 14 15 16 17 18 19 20 E /N (dB) b 0 PER in Long Delay Environments with 3-tap Rake Receiver Liang Li (Vinno), C.Y. Yang (BUAA)

  20. PICS Table C.4 Radio Frequencies Liang Li (Vinno), C.Y. Yang (BUAA)

  21. Summary • Regulatory rules for China may require reduced side lobes: -36 dBm @ non specified distance from carrier • Robust non-coherent detection of MPSK-RC can be achieved with well-known differential MSK-type detectors with no loss in performance, i.e. performance is same as the OQPSK mode @ 900 MHz • RC shaping is recommended w.r.t. EVM < 35% • The MPSK modulation are recommended as one of proposals to implement the PHY layer operation in LR-WPAN. Liang Li (Vinno), C.Y. Yang (BUAA)

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