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Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 1
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: [ System Simulation ]Date Submitted: [ Dec.16, 2004 ]Source: [Liang Li, Liang Zhang, Yafei Tian, Chenyang Yang, Zhijian Hu, HongYu Gu ] Company: [.WXZJ Inc.]Address: [Building D, No.2, Shangdi XinXi Lu, Beijing, China 100085 ]Voice:[8610-13911895301], E-Mail:[[email protected]]
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.
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 2
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: [ Analysis of E16 for 868/915 Band PHY]Date Submitted: [Dec. 2004 ]Source: [Liang Li, Liang Zhang, Yafei Tian, Chenyang Yang, Zhijian Hu ] Company: [WXZJ]Address: [2 Xinxi St, Building D, Haidian District, Beijing, China 100085 ]Voice:[86-10-139-11895301], E-Mail:[[email protected]]
Re: [ IEEE 802.15.4 ]
Abstract: [Analysis of E16 orthogonal spreading code for 868/915MHz band PHY.]
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.
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 3
Overview
This document offers key parameters of E16, and the system performances of E16 orthogonal code for 915MHz and 868MHz system:
• 915MHz PHY:– PSD of E16 and PHY parameters– Synchronization performance
- in the presence of frequency offset – System performance
Sync error, phase noise, sampling error, frequency offset, Rayleigh channel,
• 868MHz PHY:– PSD of E16 and PHY parameters– Synchronization performance
- in the presence of frequency offset – System performance
Sync error, phase noise, sampling error, frequency offset, Rayleigh channel,
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 4
OPSK variants reviewed in this presentation
E16 for 868MHz E16 for 915MHz
Bandwidth 600KHz 1.5MHz
Chip rate 400k 1M
Bit rate 100kbps 250kbps
Spectral efficiency Contain 99% energy in 0.79 normalized bandwidth
Contain 99% energy in 1.2 normalized bandwidth
Spreading 16-chip seq per 4bits 16-chip seq per 4bits
RF backward compatibility
MSK+Tx filter or GMSK MSK
Comments Quasi constant amplitude and continuous phase
Constant amplitude and continuous phase
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 5
DSSS Sequence E16Decimal Symbol
Binary Symbol Chip Values
0 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 1 1 1 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
The spread sequence corresponding to binary symbol “0000” is used for sync
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 6
OPSK Proposal
E16 Orthogonal Spreading Sequence
for 915 MHz PHY
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 7
915 MHz Band PHY
•Key design parameters –Summary of design requirements for the TG4b PHY
•PSD of E16•Auto-correlation performance of E16
– Auto-correlation of O-QPSK with half sine pulse shaping / I/Q modulation at 2x 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
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 8
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
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 9
PSD of Tx Waveform (OQPSK+E16)
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.
otherwise
TtT
ttp c
c
0
20,2
sin)(
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 10
PSD Characteristic
• PSD of OQPSK+E16 at 915Band is not affected by sampling error.
• Low out-of-band emission, and no need for Tx filter• Satisfies the IEEE 802.15.4 PSD requirements (in the 915
band)
Source: IEEE 802.15.4 Standard
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 11
Auto-correlation performance
Synchronization performance of E16 based on simulations:
• Auto-correlation characteristics with MSK modulation in 2x sampling rate
• Synchronization performance in the presence of frequency offset
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 12
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 modulated E16
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 13
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 40ppm– Center frequency = 915MHz– Average over 1 million Monte-Carlo simulations
Notes: 1. Synchronization is achieved by correlating local PN with
received preamble impaired by frequency offset. 2. Throughout this document, the perfect synchronization
(no error) in a multipath environment is defined as the receiver being synchronized to the strongest path.
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 14
AWGN Model---Synchronization performance
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 15
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 SFD detection– No fading
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 16
Simulation modelsDiscrete 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;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 17
AWGN: Ideal Sync. vs. Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoSFD: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 18
AWGN simulation results
• The BER results are close to the theoretical curve of 16-FSK.
• The sync error (using received signals correlated directly with local PN) has minimal effects on performance curves at low Eb/N0, and almost no effects in high SNR condition.
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 19
Multiple-path Model without Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoPhase noise :NoSFD: NoSync.: CorrelationDown sampling error: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 20
Multiple-path model without Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoPhase noise :NoSFD: NoSync.: CorrelationDown sampling error: Yes
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 21
Multiple-path model without Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoPhase noise :YESSFD: NoSync.: CorrelationDown sampling error: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 22
Multiple-path model without Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoPhase noise :YESSFD: YESSync.: CorrelationDown sampling error: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 23
Multiple-path model without Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: YESPhase noise :YESSFD: YesSync.: CorrelationDown sampling error: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 24
Multiple-path model without Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: YESPhase noise :YESSFD: YesSync.: CorrelationDown sampling error: Yes
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 25
Multiple-path model with Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoPhase noise :NoSFD: NoSync.: CorrelationDown sampling error: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 26
Multiple-path model with Fading + Correlation Sync.
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: YesPhase noise :YesSFD: YesSync.: CorrelationDown sampling error: No
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 27
OQPSK Proposal
E16 Orthogonal Spreading Sequence
for 868 MHz PHY
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 28
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
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 29
OPSK variants reviewed in this presentation
I. E16 for 868MHz II. E16 for 868MHz
Bandwidth 600KHz 600KHz
Chip rate 400k 400k
Bit rate 100kbps 100kbps
Spectral efficiency Contain 99% energy in 0.79 normalized bandwidth
Contain 99% energy in 0.79 normalized bandwidth
Spreading 16-chip seq per 4bits 16-chip seq per 4bits
RF backward compatibility
MSK+Tx filter GMSK
Comments <1dB PAPR Constant amplitude and continuous phase
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 30
868 MHz Band PHY
•Key design parameters –Summary of design requirements for the TG4b PHY
•PSD of TX waveform at 868MHz• RX Performance with E16 at 868MHz Band
–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
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 31
Simulation models useDiscrete exponential channel model–-Sampled version 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;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 32
Ia. OQPSK + half sine pulse without Tx filter
Tx / Rx performance at 868MHz, 600KHz bandwidth
• E16 orthogonal code + OQPSK + half-sine pulse shaping • Tx: PSD, No shaping Filter;• RX: Synchronization performance • Receiver (Non-Rake) performance comparison based on
our simulation results
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 33
100kbps Data rate PSD
• 100kbps;• 400k chip rate;• 600k bandwidth;• half sine pulse shape;• No Tx filter;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 34
100kbps Data rate performance
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoSFD: NoIdeal sync
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 35
Ib. OQPSK + half sine pulse with Tx filter
Tx / Rx Performance at 868MHz, 600KHz bandwidth
Assumption:• E16 orthogonal code + OQPSK + half-sine pulse shaping • Tx: PSD, 6 taps Tx digital raised cosine filter with r=0.2;• Rx: Synchronization performance • Receiver (Non-Rake) performance comparison based on
our simulation results
In the following slides, two Tx filters will be analyzed at 2x sampling rate and 4x sampling rate, respectively.
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 36
Freq 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;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 37
Impulse response of Tx filter –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;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 38
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)
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 39
PAPR of 100kbps with Tx filter
PAPR is less than 1dB
(about 0.8~0.9dB)
The amplitudes of samples after Tx filter
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 40
100kbps Data rate performance
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4
Frame Detection: NoSFD: NoIdeal syncTx filter
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 41
Freq Response --- 0 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;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 42
Impulse response of Tx filter –raised cosine filter r=0.2
SUPPOSE:1, 0.8MHz (4x)sampling rate;2, 250kHz pass band;
3, Tx digital FIR filter; 4, 6 taps;
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 43
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)
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 44
PAPR of 100kbps with Tx filter
PAPR is less than 1dB
(about 0.4~0.5dB)
The amplitudes of samples after Tx filter
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 45
Nonlinear PA Characteristics
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 46
Impact of PA Nonlinearity: 2x sampling rate
(1) Tx PSD without Tx filter or PA
(2) Tx PSD with Tx filter, no PA
(3) Tx PSD with Tx filter and PA
Because of aliasing at relatively low sampling rate, the signal side-lobe is susceptible to PA nonlinearity.
(1) (2)
(3)
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 47
Impact of PA Nonlinearity: 4x sampling rate
(1) Tx PSD without Tx filter or PA
(2) Tx PSD with Tx filter, no PA
(3) Tx PSD with Tx filter and PA
At 4x sampling rate, the impact of PA nonlinearity is neglectable.
(1) (2)
(3)
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 48
II. 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
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 49
GMSK sequences generated
MSK modul ator:FM modul atorwi th h=0. 5
i nput data ouput data
Gaussi anfi l ter
i nput dataGMSK modul ator: FM modul ator
wi th h=0. 5
ouput data
Method I :
MSK modul ator:hal f si ne
pul se
i nput data ouput data
GMSKpul se
i nput dataGMSK modul ator: Phase
i ntegrator
ouput data
Method II :
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 50
100kbps Data rate – GMSK modulation
• 100kbps;• 400k chip rate;• 600k bandwidth;• half sine pulse shape;• No Tx filter;• Gaussian filter before
MSK modulation with r=0.2
Dec. 2004 doc:IEEE802.15-04-0628-03-004b
Slide 51
GMSK(r=0.2) 100kbps Data rate performance
Packet Number: 10000 PSDU Length: 20 ByteTx/Rx Over Sample Rate: 2Channel Over Sample Rate: 4Ideal sync
Frame Detection: NoSFD: Norms delay spread 250nsBER and PER of GMSK is calculated theoretically
