doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> March 2005 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Enhanced E16 Code with Offset QPSK for 802.15.4b High Rate Alt-PHY] Date Submitted: [13 Jan, 2004] Source: [Liang Zhang, Hongyu Gu, Liang Li, Yafei Tian, Chenyang Yang, Zhijian Hu, Yong Guan] Company: [WXZJ Inc.] Address: [2 Xinxi St, Building D, Haidian District, Beijing, China 100085 ] Voice:[86-10-139-11895301], E-Mail:[liang_1@yahoo.com] Re: [Response to the call for proposal of IEEE 802.15.4b] Abstract: [This presentation compares all proposals for the IEEE802.15.4b PHY standard.] Purpose: [Proposal to IEEE 802.15.4b Task Group] 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 <author>, <company>

March 2005 Motivation Choose DSSS code sequences that will lead to efficient transmission and low implementation complexity. Liang Li, WXZJ

Six desirable properties of DSSS code sequences March 2005 Six desirable properties of DSSS code sequences All sequences contain equal number of ones and zeros All sequences contain equal number of ones and zeros in the even numbered chips (I phase) All sequences contain equal number of ones and zeros in the odd numbered chips (Q phase) Total phase rotation in I / Q plane accumulates to 0 degree over a complete symbol period The first 8 symbols are shifted versions of each other The last 8 symbols have inverted odd numbered chips (Q phase); when compared to the 8 first symbols, have the exact inverted baseband phase Liang Li, WXZJ

Issue: Non-zero DC value of E16 DSSS Sequence March 2005 Issue: Non-zero DC value of E16 DSSS Sequence DC values Decimal Symbol Binary Symbol Chip Values 0 0 0 0 0 0 1 1 0 1 0 0 0 1 0 0 0 1 0 0 1 1 0 0 0 0 1 1 0 0 0 0 1 0 0 0 1 0 0 0 1 2 0 1 0 0 0 0 0 0 0 1 1 1 0 1 1 1 0 1 1 1 3 1 1 0 0 0 1 0 1 0 0 1 0 0 0 1 0 0 0 1 0 4 0 0 1 0 0 0 1 1 1 0 1 1 0 1 0 0 1 0 1 1 5 1 0 1 0 0 1 1 0 1 1 1 0 0 0 0 1 1 1 1 0 6 1 1 1 0 0 0 0 0 1 0 0 0 0 1 1 1 1 0 0 0 7 0 1 1 1 0 1 0 1 1 1 0 1 0 0 1 0 1 1 0 1 8 0 0 0 1 0 0 1 1 0 1 0 0 1 0 1 1 1 0 1 1 9 1 0 0 1 0 1 1 0 0 0 0 1 1 1 1 0 1 1 1 0 10 0 1 0 1 0 0 0 0 0 1 1 1 1 0 0 0 1 0 0 0 11 1 1 0 1 0 1 0 1 0 0 1 0 1 1 0 1 1 1 0 1 12 0 0 1 1 0 0 1 1 1 0 1 1 1 0 1 1 0 1 0 0 13 1 0 1 1 0 1 1 0 1 1 1 0 1 1 1 0 0 0 0 1 14 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 1 15 1 1 1 1 0 1 0 1 1 1 0 1 1 1 0 1 0 0 1 0 Total DC values = -16 Source doc.: IEEE 802.15-04-0314-02-004b Liang Li, WXZJ

Proposed Symbol-to-Chip Mapping (Enhanced 16-chip Code Set W16) March 2005 Proposed Symbol-to-Chip Mapping (Enhanced 16-chip Code Set W16) Decimal Value Binary Symbol Chip Value DC Value 0000 0 0 1 1 1 1 1 0 0 0 1 0 0 1 0 1 1 1000 1 0 0 1 0 1 0 0 1 0 0 0 1 1 1 1 2 0100 0 0 0 0 1 1 0 1 0 0 0 1 0 1 1 0 -4 3 1100 0 1 0 1 1 0 0 0 0 1 0 0 0 0 1 1 4 0010 1 1 0 0 1 1 1 0 1 1 0 1 0 1 0 1 4i 5 1010 1 0 0 1 1 0 1 1 1 0 0 0 0 0 0 0 –4i 6 0110 0 0 0 0 0 0 1 0 0 0 0 1 1 0 0 1 -4 –4i 7 1110 1 0 1 0 1 0 0 0 1 0 1 1 0 0 1 1 4 -4i 8 0001 1 1 0 0 0 0 0 1 0 0 1 0 0 1 0 1 9 1001 0 1 1 0 1 0 1 1 1 0 0 0 1 1 1 1 10 0101 1 1 1 1 0 0 1 0 0 0 0 1 0 1 1 0 11 1101 0 1 0 1 1 0 0 0 1 0 1 1 1 1 0 0 12 0011 1 1 0 0 1 1 1 0 0 0 1 0 1 0 1 0 13 1011 1 0 0 1 1 0 1 1 0 1 1 1 1 1 1 1 4+4i 14 0111 1 1 1 1 1 1 0 1 0 0 0 1 1 0 0 1 15 1111 0 1 0 1 0 1 1 1 1 0 1 1 0 0 1 1 Total DC Value 0 +0i Liang Li, WXZJ

The Features of W16 Sequences March 2005 The Features of W16 Sequences l Having same features of DSSS sequences of 802.15.4 std: 1.  Equal number of “0”s and “1”s in preamble sequence; 2.  The first chip is not always 0 or 1; 3.  Total DC value is 0, even though not always 0 in every sequence; 4.  The phase comes back to 0 after one symbol period. l Maintaining good characteristics of E16 sequences: 1.  Orthogonality characteristics introduced by Walsh conversion; 2.  Performance similar to that of E16 orthogonal sequences; 3.  Low complexity of correlation decoder implementation.   Liang Li, WXZJ

Key Parameters of W16 (1) Bit rate of 250 kBit/s March 2005 Key Parameters of W16 (1) Bit rate of 250 kBit/s Better orthogonal characteristic 16 sequences for 4 bits mapping Each consisting of 16 chips Chip rate = 1Mchips per second Center frequency = 915MHz; Bandwidth, pulse shape,PAPR, frequency offset The 1st null-null bandwidth 1.5MHz; Half-sine pulse shape; 0dB PAPR, same MSK scheme as 15.4, constant modulus and continuous phase, lower out-of-band emission; PSD: 30dB lower over 2MHz-wide bandwidth, conforming to 802.15.4 std; Frequency offset tolerance over 40ppm; Liang Li, WXZJ

Key Parameters of W16 (2) Multipath fading robustness March 2005 Key Parameters of W16 (2) Multipath fading robustness Achieving PER<10-2 in multipath channels of 250ns rms delay spread (channel model suggested by Paul) Support of current RF Support 2 MHz-wide channels as allocated in the USA and other countries Low cost and low power consumption Liang Li, WXZJ

PSD of W16 Bandwidth, Pulse shape: March 2005 PSD of W16 Bandwidth, Pulse shape: The 1st null-null bandwidth 1.5MHz; Half-sine pulse shape: MSK modulation offers constant modulus and continuous phase; PSD 30dB lower at 1.5MHz from center frequency. Liang Li, WXZJ

W16 PSD characteristic PSD of W16 is not affected by sampling error. March 2005 W16 PSD characteristic PSD of W16 is not affected by sampling error. Low out-of-band emission: no need for Tx filter Satisfies the IEEE 802.15.4 PSD requirements Source: IEEE 802.15.4 Standard Liang Li, WXZJ

Auto-correlation performance March 2005 Auto-correlation performance Synchronization performance of W16 based on simulations: Auto-correlation characteristics with MSK modulation in 2x sampling rate Synchronization performance in the presence of frequency offset Liang Li, WXZJ

The Auto-Correlation of W16 and En- Cobi 16 March 2005 The Auto-Correlation of W16 and En- Cobi 16 En-Cobi 16 W16 In this test, the correlations are calculated after spreading sequences are OQPSK modulated with half-sine pulse shaping. Liang Li, WXZJ

Cross-correlation of received Signals of W16 and En-Cobi16 March 2005 Cross-correlation of received Signals of W16 and En-Cobi16 W16 En-Cobi16 (2x over sampling rate) Liang Li, WXZJ

Frequency offset performance March 2005 Frequency offset 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 40ppm 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

Frequency offset performance: simulations March 2005 Frequency offset performance: simulations Sync performance BER performance Frequency offset affects the sync and decoding performance significantly. So, frequency offset should be considered in 154b system. Liang Li, WXZJ

Preamble here proposed for 15.4b: March 2005 Proposal for preamble Preamble of 15.4 standard: Preamble here proposed for 15.4b: The preamble field proposed here consists of at least 4 octets (prefer 6 octets). Liang Li, WXZJ

System performance comparison between W16 and COBI16 March 2005 System performance comparison between W16 and COBI16 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 SFD detection No fading The solid curve indicates the performance of W16 and the dash one indicates the performance of COBI16 Liang Li, WXZJ

System Simulation Models March 2005 System Simulation Models Discrete exponential channel model: – Sampled version 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

AWGN: Ideal Sync. vs. Correlation Sync. March 2005 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

Multipath channel: no fading + correlation sync (1) March 2005 Multipath channel: no fading + correlation sync (1) Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Frame Detection: No Phase noise :No SFD: No Sync.: Correlation Down sampling error: No Liang Li, WXZJ

Multipath channel: no fading + correlation sync (2) March 2005 Multipath channel: no fading + correlation sync (2) Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Frame Detection: No Phase noise :No SFD: No Sync.: Correlation Down sampling error: Yes Liang Li, WXZJ

Multipath channel: no fading + correlation sync (3) March 2005 Multipath channel: no fading + correlation sync (3) Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: Yes Frame Detection: No Phase noise :No SFD: No Sync.: Correlation Down sampling error: No Liang Li, WXZJ

Multipath channel: no fading + correlation sync (4) March 2005 Multipath channel: no fading + correlation sync (4) Frame Detection: No Phase noise :YES SFD: No Sync.: Correlation Down sampling error: No Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Liang Li, WXZJ

Multipath channel: no fading + correlation sync (5) March 2005 Multipath channel: no fading + correlation sync (5) Frame Detection: No Phase noise :YES SFD: YES Sync.: Correlation Down sampling error: No Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Liang Li, WXZJ

Multipath channel: no fading + correlation sync (6) March 2005 Multipath channel: no fading + correlation sync (6) Frame Detection: YES Phase noise :YES SFD: Yes Sync.: Correlation Down sampling error: No Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Liang Li, WXZJ

Multipath channel: no fading + correlation sync (7) March 2005 Multipath channel: no fading + correlation sync (7) Frame Detection: YES Phase noise :YES SFD: Yes Sync.: Correlation Down sampling error: Yes Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Liang Li, WXZJ

Multipath channel: no fading + correlation sync (8) March 2005 Multipath channel: no fading + correlation sync (8) Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: Yes Frame Detection: YES Phase noise :YES SFD: Yes Sync.: Correlation Down sampling error: Yes Liang Li, WXZJ

March 2005 Multipath channel without Fading + Correlation Sync. (frequency offset estimation) Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: Yes Frame Detection: YES Phase noise :YES SFD: Yes Sync.: Correlation Down sampling error: Yes Liang Li, WXZJ

Multipath channel with fading + correlation Sync (1) March 2005 Multipath channel with fading + correlation Sync (1) Frame Detection: No Phase noise: No SFD: No Sync.: Correlation Down sampling error: No Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Liang Li, WXZJ

Multipath channel with fading + correlation Sync (2) March 2005 Multipath channel with fading + correlation Sync (2) Frame Detection: Yes Phase noise :Yes SFD: Yes Sync.: Correlation Down sampling error: No Packet Number: 10000 PSDU Length: 20 Byte Tx/Rx Over Sample Rate: 2 Channel Over Sample Rate: 4 Time offset: No Liang Li, WXZJ

Nonlinear PA Characteristics March 2005 Nonlinear PA Characteristics Liang Li, WXZJ

Impact of PA Nonlinearity: 2x sampling rate March 2005 Impact of PA Nonlinearity: 2x sampling rate (1) Tx PSD without PA (2) Tx PSD with PA For the constant module and continuous phase in our proposal, the Tx PSD is not affected by nonlinear PA. Liang Li, WXZJ

Summary Enhanced W16 can satisfy the 6 criteria March 2005 Summary Enhanced W16 can satisfy the 6 criteria No spikes in frequency spectrum The sync performance using correlation method is the same as the COBI16 (d1), and the performance of demodulation is slightly better than that of COBI16(d1) The system PER performance of W16 is slightly better than that of COBI16(d1), especially in condition of large delay spread Liang Li, WXZJ