1 / 39

System Simulation for OPSK Modulation in 915MHz and 868MHz PHY

This document presents the analysis of orthogonal code in OPSK modulation for the physical layer (PHY) of 915MHz and 868MHz systems. Key parameters, PSD analysis, synchronization performance, and system performance are discussed.

mcgregorc
Télécharger la présentation

System Simulation for OPSK Modulation in 915MHz and 868MHz PHY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ System Simulation ] Date Submitted: [ Dec.16, 2004 ] Source: [Liang Li, Liang Zhang, Yafei Tian, Chenyang Yang, Zhijian Hu ] Company: [.WXZJ Inc.] Address: [Building D, No.2, Shangdi XinXi Lu, Beijing, China 100085 ] Voice:[8610-13911895301], E-Mail:[liang_1@yahoo.com] Re: [ IEEE 802.15.4 ] Abstract: [The analysis of orthogonal code in OPSK modulation for PHY of 915MHz and 868MHz.] Purpose: [To encourage discussion.] 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, WXZJ Inc.

  2. Overview This document offers key parameters of E16, and the system performances of E16 orthogonal code for 915MHz and 868MHz system: • 915MHz system: • PSD analysis of E16 and design parameters; • Synchronization performance - in the presence of frequency offset • System performance Sync error, phase noise, sampling error, frequency offset, Rayleigh channel, • 868MHz system: • PSD analysis of E16 and design parameters • Synchronization performance - in the presence of frequency offset • System performance Sync error, phase noise, sampling error, frequency offset, Rayleigh channel, Liang Li, WXZJ Inc.

  3. OPSK variants reviewed in this presentation Liang Li, WXZJ Inc.

  4. OPSK Proposal Orthogonal Sequence of E16 for PHY of 915MHz system Liang Li, WXZJ Inc.

  5. Presentation (915MHz) Contents •Key design parameters –Summary of design requirements for the TG4b PHY •PSD of E16 •Auto-correlation performance of E16 –Auto-correlation withO-QPSK / half sine pulse / I/Q modulation 2M sampling rate –sync in condition of frequency offset • E16 Performance –simulation condition or system construction –AWGN and Rayleigh channel in ideal condition –Frame detection, synchronization, phase noise, frequency offset, sampling error, respectively (to be continued) •Summary Liang Li, WXZJ Inc.

  6. Key Parameters of E16 • Bit rate 250 kBit/s • Better orthogonal characteristic • 16 sequences for 4 bits mapping • Each consist of 16 chips • 1M chip rate per second • Center frequency is 915MHz; • Bandwidth, Pulse shape , PAPR, frequency offset • The 1st null-null bandwidth 1.5MHz; • Half-sine pulse shape; • 0dB PAPR, the same MSK scheme as 15.4, constant module and continuous phase,lower out-of-band emission; • 30dB lower over 2M wide bandwidth, which satisfies the state of 15.4; • Tolerated frequency offset at least 40ppm; • Multipath fading robustness • Achieve PER<10^-2 at channels with 250ns delay spread ((Multipath channel model offer by Paul with high sampling rate); • Support of current RF • Support 2 MHz wide channels in the USA and other countries were they are permitted • Low cost and low power consumption Liang Li, WXZJ Inc.

  7. PSD of E16 • Bandwidth, Pulse shape: • The 1st null-null bandwidth 1.5MHz; • Half-sine pulse shape, • MSK modulation offers constant module and continuous phase; • 30dB lower over 2M wide bandwidth; Liang Li, WXZJ Inc.

  8. E16 PSD characteristic • PSD of E16 is not influenced by sampling error; • Lower out-of-band emission, and no more Tx filter tolow the PSD out of band; • Satisfy the PSD spectrum according to the Std. 15.4 From the Std. of IEEE 802.15.4 Liang Li, WXZJ Inc.

  9. Auto-correlation performance Auto-correlation Performance of E16 orthogonal code is made based on simulations, Synchronization performance: • Auto-correlation characteristics with MSK modulation in 2M sampling rate • Synchronization performance in the presence of frequency offset Liang Li, WXZJ Inc.

  10. Auto-correlation of modulated E16 In this test, E16 spreading sequences are first OQPSK modulated with half-sine pulse shaping, and then the correlations are calculated. Auto-correlation of modulatedE16 Liang Li, WXZJ Inc.

  11. Synchronization performance Simulation parameters & assumptions: • Rayleigh Channel model as suggested at TG4 discussions • O-QPSK + half-sine pulse shaping • 2M sampling rate (1M chips/sec) • Frequency offset from 0ppm to 30ppm • Center frequency = 915MHz • Average over 1 million Monte-Carlo simulations Notes: • Synchronization is achieved by correlating local PN with received preamble impaired by frequency offset. • Throughout this document, the perfect synchronization (no error) in a multipath environment is defined as the receiver being synchronized to the strongest path. Liang Li, WXZJ Inc.

  12. Synchronization performance Liang Li, WXZJ Inc.

  13. System performance Simulation parameters & assumptions: • 250ns rms delay spread Rayleigh Channel model • O-QPSK modulation + half sine pulse • without frequency offset • without synchronization error • 20 octets in each packet • 10,000 packets for Monte-Carlo simulation • Non-coherent demodulation • No SFDdetection • No fading Liang Li, WXZJ Inc.

  14. Simulation models use Discrete exponential model –-Sampled version of diffuse model of diffuse channel model offer by Paul with 4MHz sampling rate; –At least 10000 random channel realizations; –PER calculated on 20 bytes PPDUs with preamble; Liang Li, WXZJ Inc.

  15. AWGN: Ideal Sync. vs. Correlation Sync. Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Frame Detection: No SFD: No Liang Li, WXZJ Inc.

  16. AWGN simulation results • The BER results can mostly reach the theoretic curve of 16-FSK; • The sync error using received signals correlated directly with local PN has a little effects on performance curves in low Eb/N0 condition, and almost no effects in high SNR condition; Liang Li, WXZJ Inc.

  17. Multiple-path Model without Fading + Correlation Sync. Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Frame Detection: No Phase noise :No SFD: No Sync.: Correlation No down sampling error Liang Li, WXZJ Inc.

  18. Multiple-path Model without Fading + Correlation Sync. Frame Detection: No Phase noise :YES SFD: No Sync.: Correlation No down sampling error Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Liang Li, WXZJ Inc.

  19. Multiple-path Model without Fading + Correlation Sync. Frame Detection: No Phase noise :YES SFD: YES Sync.: Correlation No down sampling error Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Liang Li, WXZJ Inc.

  20. Multiple-path Model without Fading + Correlation Sync. Frame Detection: YES Phase noise :YES SFD: Yes Sync.: Correlation No down sampling error Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Liang Li, WXZJ Inc.

  21. OPSK Proposal Orthogonal Sequence of E16 for PHY of 868MHz system Liang Li, WXZJ Inc.

  22. Key Parameters of E16 • Bit rate 100 kBit/s • Better orthogonal characteristic • 16 sequences for 4 bits mapping • Each consist of 16 chips • 400k chip rate per second • Center frequency is 868MHz; • Bandwidth, Pulse shape , PAPR, frequency offset • The 1st null-null bandwidth 600kHz; • 0dB PAPR, • GMSK modulation with r=0.2, constant module and continuous phase,lower out-of-band emission; • Nearly 50dB lower over 600kHz wide bandwidth, which satisfies the state of ETSI; • Tolerated frequency offset at least 40ppm; • Multipath fading robustness • Achieve PER<10^-2 at channels with 250ns delay spread (Multipath channel model offer by Paul with high sampling rate); • Support of current RF • Support current 600kHz band available at 1% duty cycle in Europe today • Allow use of extended European bands and bands in other countries once they become available • Allow addition of additional 600 kHz channels as per current ETSI / ECC report (4/6 channels?) • Do not expect US-like wide, unrestricted bands or all egulatorydomains • Support of more flexible channel selection method to flexibly add support for more countries • Low cost and low power consumption Liang Li, WXZJ Inc.

  23. OPSK variants reviewed in this presentation Liang Li, WXZJ Inc.

  24. Presentation (868MHz) Contents •Key design parameters –Summary of design requirements for the TG4b PHY •PSD of E16 •Auto-correlation performance of E16 –Auto-correlation withGMSK r=0.2 / I/Q modulation –sync in condition of frequency offset • E16 Performance –simulation condition or system construction –AWGN and Rayleigh channel (theoretical PER results) in ideal condition –Frame detection, synchronization, phase noise, frequency offset, sampling error, respectively (to be continued) •Summary Liang Li, WXZJ Inc.

  25. Simulation models use Discrete exponential model –-Sampled version of diffuse model of diffuse channel model offer by Paul with 4x sampling rate; –At least 10000 random channel realizations; –PER calculated on 20 bytes PPDUs with preamble; Liang Li, WXZJ Inc.

  26. Ia. OQPSK + half sine pulse without Tx filer TX/ RX Performance within 600KHz at 868MHz Assumption: • E16 Orthogonal code +QPSK + Half-Sine • TX: PSD, No shaping Filter; • RX: Synchronization performance • Receiver (Non-Rake) performance comparison based on our simulation results Liang Li, WXZJ Inc.

  27. 100kbps Data rate PSD • 100kbps; • 400k chip rate; • 600k bandwidth; • half sine pulse shape; • No Tx filter; Liang Li, WXZJ Inc.

  28. 100kbps Data rate performance Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Frame Detection: No SFD: No Ideal sync Liang Li, WXZJ Inc.

  29. Ib. OQPSK + half sine pulse with Tx filer TX/ RX Performance within 600KHz at 868MHz Assumption: • E16 Orthogonal code +QPSK + Half-Sine • TX: PSD, 6 taps Tx digital filter with r=0.2; • RX: Synchronization performance • Receiver (Non-Rake) performance comparison based on our simulation results In the next slides, two Tx filters will be introduced in condition of 2x sampling rate and 4x sampling rate, respectively. Liang Li, WXZJ Inc.

  30. Frequency Response–raised cosine filter r=0.2 SUPPOSE: 1, 0.8MHz (2x)sampling rate; 2, 250kHz pass band; 3, Tx digital FIR filter; 4, 6 taps; Liang Li, WXZJ Inc.

  31. 100kbps Data rate PSD with Tx filter • 100kbps; • 400k chip rate; • 600k bandwidth; • half sine pulse shape; • 6 taps FIR Tx filter; • Raised cosine filter with r=0.2; • 2x over sampling rate; (0.8M sampling rate) Liang Li, WXZJ Inc.

  32. PAPR of 100kbps with Tx filter PAPR is less than 1dB (about 0.8~0.9dB) The amplitudes of samples after Tx filter Liang Li, WXZJ Inc.

  33. Frequency Response–raised cosine filter r=0.2 SUPPOSE: 1, 1.6MHz (4x)sampling rate; 2, 250kHz pass band; 3, Tx digital FIR filter; 4, 8 taps; Liang Li, WXZJ Inc.

  34. 100kbps Data rate PSD with Tx filter • 100kbps; • 400k chip rate; • 600k bandwidth; • half sine pulse shape; • 8 taps FIR Tx filter; • Raised cosine filter with r=0.2; • 4x over sampling rate; (1.6M sampling rate) Liang Li, WXZJ Inc.

  35. PAPR of 100kbps with Tx filter PAPR is less than 1dB (about 0.4~0.5dB) The amplitudes of samples after Tx filter Liang Li, WXZJ Inc.

  36. II. Try the Improved QPSK---GMSK TX/ RX Performance within 600KHz at 868MHz Assumption: • E16 Orthogonal code +GMSK • TX: PSD, No filter; • RX: Synchronization performance • Receiver (Non-Rake) performance comparison based on our simulation results Liang Li, WXZJ Inc.

  37. GMSK sequences generated Method I : Method II : Liang Li, WXZJ Inc.

  38. 100kbps Data rate – GMSK modulation • 100kbps; • 600k chip rate; • 600k bandwidth; • half sine pulse shape; • No Tx filter; • Gaussian filter before MSK modulation with r=0.2 Liang Li, WXZJ Inc.

  39. GMSK(r=0.2) 100kbps Data rate performance Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Ideal sync Frame Detection: No SFD: No rms delay spread 250ns BER and PER of GMSK is calculated theoretically Liang Li, WXZJ Inc.

More Related