SystemVue - ZigBee Baseband Verification Library. SystemVue ZigBee Baseband Verification Library

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2 SystemVue ZigBee Baseband Verification Library 1

3 Agilent Technologies, Inc Page Mill Road, Palo Alto, CA USA No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or translation into a foreign language) without prior agreement and written consent from Agilent Technologies, Inc as governed by United States and international copyright laws Acknowledgments Mentor Graphics is a trademark of Mentor Graphics Corporation in the US and other countries Microsoft, Windows, MS Windows, Windows NT, and MS-DOS are US registered trademarks of Microsoft Corporation Pentium is a US registered trademark of Intel Corporation PostScript and Acrobat are trademarks of Adobe Systems Incorporated UNIX is a registered trademark of the Open Group Java is a US trademark of Sun Microsystems, Inc SystemC is a registered trademark of Open SystemC Initiative, Inc in the United States and other countries and is used with permission MATLAB is a US registered trademark of The Math Works, Inc HiSIM2 source code, and all copyrights, trade secrets or other intellectual property rights in and to the source code in its entirety, is owned by Hiroshima University and STARC Errata The SystemVue product may contain references to "HP" or "HPEESOF" such as in file names and directory names The business entity formerly known as "HP EEsof" is now part of Agilent Technologies and is known as "Agilent EEsof" To avoid broken functionality and to maintain backward compatibility for our customers, we did not change all the names and labels that contain "HP" or "HPEESOF" references Warranty The material contained in this document is provided "as is", and is subject to being changed, without notice, in future editions Further, to the maximum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied, with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a particular purpose Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or performance of this document or of any information contained herein Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the separate agreement shall control Technology Licenses The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license Portions of this product is derivative work based on the University of California Ptolemy Software System In no event shall the University of California be liable to any party for direct, indirect, special, incidental, or consequential damages arising out of the use of this software and its documentation, even if the University of California has been advised of the possibility of such damage The University of California specifically disclaims any warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose The software provided hereunder is on an "as is" basis and the University of California has no obligation to provide maintenance, support, updates, enhancements, or modifications Portions of this product include code developed at the University of Maryland, for these portions the following notice applies In no event shall the University of Maryland be liable to any party for direct, indirect, special, incidental, or consequential damages arising out of the use of this software and its documentation, even if the University of Maryland has been advised of the possibility of such damage The University of Maryland specifically disclaims any warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose the software provided hereunder is on an "as is" basis, and the University of Maryland has no obligation to provide maintenance, support, updates, enhancements, or modifications Portions of this product include the SystemC software licensed under Open Source terms, which are available for download at This software is redistributed by Agilent The Contributors of the SystemC software provide this software "as is" and offer no warranty of any kind, express or implied, including without limitation warranties or conditions or title and non-infringement, and implied warranties or conditions merchantability and fitness for a particular purpose Contributors shall not be liable for any damages of any kind including without limitation direct, indirect, special, incidental and consequential damages, such as lost profits Any provisions that differ from this disclaimer are offered by Agilent only 2

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5 4 About ZigBee Baseband Verification Library 5 ZigBee System 5 ZigBee Library 8 UWB_Channel Part 9 UWB_Channel 9 ZigBee_Despread Part 11 ZigBee_Despread 11 ZigBee_DemuxFrame Part 12 ZigBee_DemuxFrame 12 ZigBee_Receiver Part 14 ZigBee_Receiver 14 ZigBee_Source Part 17 ZigBee_Source 17 ZigBee_FrameSync Part 20 ZigBee_FrameSync 20

6 About ZigBee Baseband Verification Library The is a part of IEEE family of standards for physical and link-layers for wireless personal area networks(wpans) The WPAN working group focuses on short range wireless links, in contract to local area and metropolitan area coverage explored in WLAN and WMAN working groups, respectively The focal area of the IEEE is that of low data rate WPANs, with low complexity and stringent power consumption requirements The Agilent EEsof SystemVue ZigBee Wireless Design Library is provided for the ZigBee market This design library follows the IEEE Std The ZigBee Design Library is intended to be a baseline system for designers to develop an idea of what nominal or ideal system performance would be Evaluations can be made regarding degraded system performance due to system impairments that may include non-ideal component performance ZigBee System Modulation types, frequency bands and data rates The IEEE specifies four PHYs An 868/915 MHz direct sequence spread spectrum (DSSS) PHY employing binary phase-shift keying(bpsk) modulation An 868/915 MHz DSSS PHY employing offset quadrature phase-shift keying (O- QPSK) modulation (optional) An 868/915 MHz parallel sequence spread spectrum (PSSS) PHY employing BPSK and amplitude shift keying (ASK) modulation (optional) A 2450MHz DSSS PHY employing O-QPSK modulation The frequency bands and data rates are summaries in table 1 Table 1: Frequency bands and data rates The 868/915MHz DSSS using binary phase-shift keying(bpsk) modulation and the 2450MHz DSSS using O-QPSK modulation are supported in the ZigBee Design Library PPDU format Each PPDU packet consists of the following basic components: A synchronization header (SHR), which allows a receiving device to synchronize and lock onto the bit stream A PHY header (PHR), which contains frame length information A variable length payload, which carries the MAC sublayer frame The PPDU packet structure shall be formatted as illustrated in Table 2 Table 2:Format of the PPDU 5

7 2450MHz PHY specifications Modulation and spreading The 2450 MHz PHY employs a 16-ary quasi-orthogonal modulation technique During each data symbol period, four information bits are used to select one of 16 nearly orthogonal pseudo-random noise (PN) sequences to be transmitted The PN sequences for successive data symbols are concatenated, and the aggregate chip sequence is modulated onto the carrier using offset quadrature phase-shift keying (O-QPSK) The reference modulation diagram is illustrated in figure 1 Figure 1: Modulation and spreading functions for OQPSK The symbol-to-chip mapping is specified in Table 3 Table 3: Symbol-to-chip mapping for O-QPSK 6

8 The chip sequences representing each data symbol are modulated onto the carrier using O-QPSK with halfsine pulse shaping Even-indexed chips are modulated onto the in-phase (I) carrier and odd-indexed chips are modulated onto the quadrature-phase (Q) carrier Because each data symbol is represented by a 32-chip sequence, the chip rate (nominally 20 Mchip/s) is 32 times the symbol rate To form the offset between I-phase and Q-phase chip modulation, the Q-phase chips shall be delayed by Tc with respect to the I-phase chips (see Figure 19), where Tc is the inverse of the chip rate The O-QPSK chip offset is shown in figure 2 Figure 2: O-QPSK chip offsets The half-sine pulse shape used to represent each baseband chip is described by Equation 868/915MHz band binary phase-shift keying(bpsk) PHY specifications The 868/915 MHz BPSK PHY shall employ direct sequence spread spectrum (DSSS) with BPSK used for chip modulation and differential encoding used for data symbol encoding The reference modulator diagram is shown in Figure 3 7

9 Figure 3: Modulation and spreading functions for BPSK The Symbol-to-chip mapping is shown in Table 4 Table 4: Symbol-to-chip mapping for BPSK The raised cosine pulse shape (roll-off factor = 1) used to represent each baseband chip is described by Equation ZigBee Library EEsof SystemVue ZigBee library can support both 868/915MHz BPSK and 2450MHz O- QPSK modulation formats It includes 6 components and 2 test benches Component Libraries This ZigBee Wireless Design Library is organized by the types of behavioral models and subnetworks Channel Model Components UWB_Channel: UWB Channel model Mapper Components ZigBee_Despread: ZigBee despread and symbol demapper Multiplex Components ZigBee_DemuxFrame: ZigBee frame demultiplexer Receiver Components ZigBee_Receiver: ZigBee baseband receiver which both supports 868/915MHz BPSK and 2450MHz O-QPSK modulation Source Components ZigBee_Source: ZigBee baseband signal source which both supports 868/915MHz BPSK and 2450MHz O-QPSK modulation Sync Equalization Components ZigBee_FrameSync: ZigBee time and frequency synchronizer in time domain Reference 1 IEEE Std Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs) 8

10 UWB_Channel Part Categories: Channel Model (zigbeebasever) SystemVue - ZigBee Baseband Verification Library The models associated with this part are listed below To view detailed information on a model (description, parameters, equations, notes, etc), please click the appropriate link Model UWB_Channel (zigbeebasever) UWB_Channel Description UWB Channel Model Description: UWB Channel Model Domain: Untimed C++ Code Generation Support: NO Associated Parts: UWB Channel Part (zigbeebasever) Model Parameters Name Description Default Units Type Runtime Tunable ChannelNumber ChannelSeedOption Channel model type: CM_1, CM_2, CM_3, CM_4, CM_5, CM_6, CM_7, CM_8, CM_9 type of Random number seed to generate channel impulse response: Random, Fixed RandomNumberSeed Random number seed to create channel [0,2^31-1) CM_1 Enumeration NO Random Enumeration NO 0 Integer NO SampleRate sample rate of input signal [1KHz,16GHz] 8e9 Hz Float NO CarrierFrequency carrier frequency [2GHz, 10GHz] 6e9 Hz Float NO FilteringOption InterpConfig InterpAlpha InterpDelay Input Ports Port Name Description FFTBased needs more memory in non- MultiRate mode, SingleInSingleOut may be slower, FFTBasedSISO introduces extra delay: FFTBased, SingleInSingleOut, FFTBasedSISO interpolation filter parameter configuration: Default, UserDefined ratio of signal bandwidth to half sample rate with which resampling filter will be optimized [0,1) delay of interpolation filter or half the number of samples used for interpolation [4,128] Signal Type Optional 1 input Signals supplied to transmit array complex NO Output Ports FFTBased Enumeration NO Default Enumeration NO 095 Float NO 24 Integer NO Port Name Description 2 output Signals at output of receive array Notes/Equations Signal Type Optional complex NO 1 This model simulates a generic channel model representing typical indoor and outdoor environments, in the frequency range of [2GHz, 10GHz], for evaluating a systems The radio channel around the human body is not included 2 It's implemented based on the m-code in [2] 3 The output rms value is normalized to be the same as that of input signal However, if the sample rate of input is small, the output rms may be much larger than expected because some multi-path clusters are gathered in one correlative time span 4 The channel number CM_1~CM_9 correspond to different propagation environment in the following table 9

11 channel number environment CM_1 Residential LOS CM_2 Residential NLOS CM_3 Office LOS CM_4 Office NLOS CM_5 Outdoor LOS CM_6 Outdoor NLOS CM_7 Industrial LOS CM_8 Industrial NLOS CM_9 Open Outdoor NLOS SystemVue - ZigBee Baseband Verification Library References 1 IEEE a channel model - final report r a-ieee a-channel-model-matlab-code-ver-9 10

12 ZigBee_Despread Part Categories: Mapper (zigbeebasever) SystemVue - ZigBee Baseband Verification Library The models associated with this part are listed below To view detailed information on a model (description, parameters, equations, notes, etc), please click the appropriate link Model ZigBee_Despread (zigbeebasever) ZigBee_Despread Description ZigBee despread and symbol demapper Description: ZigBee despread and symbol demapper Domain: Untimed C++ Code Generation Support: NO Associated Parts: ZigBee Despread Part (zigbeebasever) Model Parameters Name Description Default Units Type Runtime Tunable PHYFormat the type of PHY format: OQPSK_2000kchips/s, BPSK_600kchips/s, BPSK_300kchips/s OQPSK_2000kchips/s Enumeration NO PSDULength PSDU payload length in bytes 20 Integer NO SamplesPerChip Samples per chip 4 Integer NO Input Ports Port Name Description Signal Type Optional 1 Input Input signal complex NO Output Ports Port Name Description Signal Type Optional 2 Output Output demapped bits int NO Notes/Equations 1 This model despreads the input sequences and demaps to binary bits For OQPSK modulation, the reverse process of bit-to-symbol mapping and symbol-to-chip mapping is performed For BPSK modulation, the reverse process of differential encoding and bit-to-chip mapping is performed 2 Each firing, DataSamples tokens are consumed at the input port, where DataSamples refers to the number of samples of PHY payload in one burst and calculated as DataSamples (zigbeebasever)it equals to 5120 by default PSDULength*8 tokens are produced at the output port 3 For OQPSK modulation, this model performs M-ary despread symbol by symbol Firstly, the half sine pulse shaped PN sequences for data symbol#0,symbol#15 are generated Then the correlations of the input signal and all the PN sequences are calculated Lastly, the symbol index of the maximum correlation is output The symbol to chip mapping is Symbol-to-chip mapping for OQPSK (zigbeebasever) The half sine pulse shape is half sine pulse shape (zigbeebasever) 4 For BPSK modulation, the differential decoding is performed after despread The input signal is correlated with the raised cosine pulse shapd PN sequence for bit 0 symbol by symbol Then the change of the phase between two symbols is detected by multipying the correlation result with the complex-conjugation of the previous correlation result The decision threshold is ±/2 The symbol to chip mapping is Symbol-to-chip mapping for BPSK (zigbeebasever) The raised cosine pulse shape is raised cosine pulse shape (zigbeebasever) References 1 IEEE Std Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs) 11

13 ZigBee_DemuxFrame Part Categories: Multiplex (zigbeebasever) SystemVue - ZigBee Baseband Verification Library The models associated with this part are listed below To view detailed information on a model (description, parameters, equations, notes, etc), please click the appropriate link Model ZigBee_DemuxFrame (zigbeebasever) ZigBee_DemuxFrame Description ZigBee frame demultiplexer Description: ZigBee frame demultiplexer Domain: Untimed C++ Code Generation Support: NO Associated Parts: ZigBee DemuxFrame Part (zigbeebasever) Model Parameters Name Description Default Units Type Runtime Tunable PHYFormat the type of PHY format: OQPSK_2000kchips/s, BPSK_600kchips/s, BPSK_300kchips/s OQPSK_2000kchips/s 12 Enumeration NO PSDULength PSDU payload length in bytes 20 Integer NO IdleInterval idle interval between two burst in chips 100 Integer NO SamplesPerChip Samples per chip 4 Integer NO DownSamplesPerChip the number of samples per chip after downsampling 4 Integer NO DownsamplingPhase initial phase for downsampling 0 Integer NO Input Ports Port Name Description Signal Type 1 Input Input signal complex NO 2 Index number of input samples from real frame start to ideally aligned frame start 3 DeltaF frequency offset detection real float NO Output Ports Port Name Description Signal Type Optional 4 Frame Frame data complex NO 5 Data data package complex NO 6 Preamble Preamble sequences Notes/Equations complex NO int Optional 1 This model is used to demultiplex ZigBee burst, which includes pre-downsampling, compensating time and carrier frequency offsets Both 868/915MHz BPSK modulation and 2450MHz O-QPSK modulation are supported 2 Each firing, FrameSamples tokens are consumed at the input port Input, where FrameSamples refers to the number of samples of one burst including idle interval and calculated as:framesamples (zigbeebasever) It is equals to 7056 by default 1 token is consumed at the input port Index 1 token is consumed at the input port DeltaF PackageSamples tokens are produced at the output port Frame, where PackageSamples refers to the number of downsampled samples in one burst excluding idle interval and calculated as: PackageSamples=(( PSDULength*8)/BitsPerSymbol*ChipsPerSymbol)*DownSamplesPerChip where the 32 refers to the number of bits for preamble, the first 8 refers to the number of bits for SDF field, the second 8 bits refers to the PHR BitsPerSymbol specifies the number of bits per symbol which equals to 1 for NO

14 3 4 5 SystemVue - ZigBee Baseband Verification Library BPSK modulation and equals to 4 for O-QPSK modulation ChipsPerSymbol specifies the number of chips per symbol which equals to 15 for BPSK modulation and equals to 32 for O-QPSK modulation It equals to 6656 by default DataSamples tokens are produced at the output port Data, where DataSamples refers to the number of downsampled samples of PHY payload in one burst and calculated as: DataSamples=(PSDULength*8/BitsPerSymbol*ChipsPerSymbol*DownSamplesPerChip) It equals to 5120 by default PreambleSamples tokens are produced at the output port Preamble, where PreambleSamples refers to the number of downsampled samples of preamble field in one burst and calculated as: PreambleSamples=32/BitsPerSymbol*ChipsPerSymbol*DownSamplesPerChip It equals to 1024 by default Because of the transmission delay, a detected burst usually falls into 2 consecutive received blocks, so the buffer length for Input is 2*FrameSamples The start point of the detected burst is determined by the token consumed at Index Only after receiving the second input block, this model can output one actual burst So this model causes one burst delay The DeltaF inputs the estimated frequency offset ( ) of each received burst The i- th estimated frequency offset ( ) compensates for the phase in the current burst only Assume( ) sequences are the input signals from Input, ( ) are the sequences, whose phase caused by frequency offset are removed, where N is the number of samples within burst Then where is frequency offset of the i-th received burst which is the input at DeltaF Tstep=ChipRate*SamplesPerChip is the sample time interval in the system ChipRate equals to 300kchips/s for 868MHz BPSK, 600kchips/s for 915MHz BPSK and 2000kchips/s for 2450MHz O-QPSK Since there are only in-phase parts for the BPSK modulation, delta omiga will be estimated and compensated to make sure the quadrature parts are zeros after frequency compensation 6 The parameter DownSamplesPerChip specifies the number of samples per chip for the output sequences The parameter DownsamplingPhase specifies which one sample to output when downsampling This parameter is ineffective when DownSamplesPerChip equals to SamplerPerChip For example, the SamplesPerChip = 3, DownSamplesPerChip = 1 means the output is decimatd by three and only 1 of every three samples is selected If DownsamplingPhase = 0, the first one of the three samples will be selected, if DownSamplingPhase = 2, the last one of the three samples will be selected The SamplesPerChip should be exactly devided by the DownSamplesPerChip in this model A low-pass filter should be used as an anti-aliasing filter to reduce the bandwidth of the signal before the signal is downsampled References 1 IEEE Std Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs) 13

15 ZigBee_Receiver Part ZigBee baseband receiver Categories: Receiver (zigbeebasever) SystemVue - ZigBee Baseband Verification Library The models associated with this part are listed below To view detailed information on a model (description, parameters, equations, notes, etc), please click the appropriate link Model ZigBee_Receiver (zigbeebasever) ZigBee_Receiver Description: ZigBee baseband receiver Associated Parts: ZigBee Receiver Part (zigbeebasever) Model Parameters Name Description Default Units Type Runtime Tunable PHYFormat the type of PHY format: OQPSK_2000kchips/s, BPSK_600kchips/s, BPSK_300kchips/s OQPSK_2000kchips/s 14 Enumeration NO PSDULength PSDU payload length in bytes 20 Integer NO IdleInterval idle interval between two burst in chips 100 Integer NO SamplesPerChip Samples per chip 4 Integer NO CorrBlockNum FreqSync SearchType TrackingRange Input Ports Port Name Description Number of oversampled samples in each sub correlation block Frequency estimation range selection: < 1/8 Symbol Rate, < 1/4 Symbol Rate, < 1/2 Symbol Rate, < Symbol Rate, < 2 Symbol Rate, < 4 Symbol Rate, < 8 Symbol Rate start a new timing and frequency synchronization search for every burst or not: Search every burst, Search+Track timing and frequency synchronization tracking range for the bursts except the first burst, valid when SearchType is Search_Track 128 Integer NO < 1/2 Symbol Rate Enumeration NO Search every burst Enumeration NO 0 Float NO Signal Type Optional 1 Input Input of frame data in time domain complex NO Output Ports Port Name Description Signal Type 2 PSDU Output of PHY payload int NO 3 Index number of input samples from real frame start to ideally aligned frame start 4 DeltaF frequency offset detection real NO 5 DataSamples data package complex NO 6 PreambleSamples Preamble sequences complex NO Parameters Details int Optional For signal parameters details please refer to ZigBee source parameters (zigbeebasever) Rx Algorithm Parameters Details: CorrBlockNum: Number of oversampled samples in each sub correlation block It is used to calculate the correlation of the received signal and local preamble to get the start position of the frame CorrBlockNum should be choosen to meet the following requirements: NO

16 1 It is larger than zero 2 It is no larger than the number of samples in one symbol 3 The number of samples in one symbol should be exactly devided by the CorrBlockNum 4 The frequency offset of the number of CorrBlockNum samples should be in the range(- π, π) which can be restrained by the receiver FreqSync:Frequency estimation range selection choosen from < 1/8 Symbol Rate, < 1/4 Symbol Rate, < 1/2 Symbol Rate, < Symbol Rate, < 2 Symbol Rate, < 4 Symbol Rate < 8 Symbol Rate The frequency estimator exhibits good accuracy while maintaining useful operating ranges The CorrBlockNum should not exceed the range of FreqSync For example, if the FreqSync is set to '< 8 Symbol Rate' which means the frequency offset of (-π, π) is for 1/8 symbol time The CorrBlockNum should be no larger than the number of samples in 1/8 symbol to restrain the frequency offset, otherwise the synchronization index may not be the right position SearchType:the search type for the timing synchronization to identify whether to start a new timing and frequency synchronization search for every burst or not When SearchType = Search every burst, the complete search is performed for each burst in the whole burst; When SearchType = Search+Track, the first burst performs the complete search in the whole burst, the rest bursts perform the tracking search whose search range is defined in TrackingRange TrackingRange: tracking range for the rest bursts when SearchType = Search+Track This parameter is valid only when SearchType = Search+Track Notes/Equations 1 2 This subnetwork completes Std ZigBee baseband receiver The ZigBee_Receiver schematic is shown below: 3 Token number The port Input reads IQ data sequences for one burst Each firing, FrameSamples tokens are produced at the port Input Please refer to FrameSamples (zigbeebasever) for the calculation in detail It is equal to 7056 by default The port PSDU produces the PHY payload The number of samples for the PSDU port per burst is calculated as:psdulength*8 It is equal to 160 by default The port Index produces the start position in sample of the burst Each firing, 1 token is produced The port DeltaF produces the frequency offset of the burst Each firing, 1 token is produced The port DataSamples produces the IQ data samples with frequency offset compansation of the burst Each firing, PSDULength*8/BitsPerSymbol*ChipsPerSymbol*DownSamplesPerChip tokens are procuded, where BitsPerSymbol specifies the number of bits per symbol which equals to 1 for BPSK modulation and equals to 4 for O-QPSK modulation ChipsPerSymbol specifies the number of chips per symbol which equals to 15 for BPSK modulation and equals to 32 for O-QPSK modulation It is equal to 5120 by default The port PreambleSamples produces the IQ data samples with frequency offset compansation of the burst Each firing, (32+8+8)/BitsPerSymbol*ChipsPerSymbol*DownSamplesPerChip tokens are produced, where the 32 refers to the number of bits for preamble, the first 8 refers to the number of bits for SDF field, the second 8 bits refers to the PHR BitsPerSymbol specifies the number of bits per symbol which equals to 1 for BPSK modulation and equals to 4 for O-QPSK modulation 15

17 ChipsPerSymbol specifies the number of chips per symbol which equals to 15 for BPSK modulation and equals to 32 for O-QPSK modulation It is equal to 1536 by default 4 First of all, the time and frequency synchronization are performed in ZigBee_FrameSync utilizing the preamble signal Both timing synchronization index and frequency offset from ZigBee_FrameSync are passed into the ZigBee_DemuxFrame as well as the received signal 5 Then ZigBee_DemuxFrame compensated the frequency offset and outputs the real burst making use of the timing synchronization index It should be noted that this model causes one burst delay 6 Lastly the ZigBee_Despread performs the reverse process of bit-to-symbol mapping and symbol-to-chip mapping by correlation with the local PN sequences The binary data is produced after the decision making References The signal can be downsampled by the parameter DownSamplesPerChip in the ZigBee_DemuxFrame and then despreaded with DownSamplesPerChip in ZigBee_Despread This will introduce the SNR loss while speeding up simulation 1 IEEE Std Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs) 16

18 ZigBee_Source Part ZigBee baseband signal source Categories: Source (zigbeebasever) SystemVue - ZigBee Baseband Verification Library The models associated with this part are listed below To view detailed information on a model (description, parameters, equations, notes, etc), please click the appropriate link Model ZigBee_Source (zigbeebasever) ZigBee_Source Description: ZigBee baseband signal source Associated Parts: ZigBee Source Part (zigbeebasever) Model Parameters Name Description Default Units Type Runtime Tunable PHYFormat the type of PHY format: OQPSK_2000kchips/s, BPSK_600kchips/s, BPSK_300kchips/s OQPSK_2000kchips/s Enumeration NO PSDULength PSDU payload length in bytes 20 Positive integer IdleInterval idle interval between two bursts in chips 100 Positive integer SamplesPerChip Samples per chip 4 Positive integer Input Ports NO NO NO Port Name Description 1 PSDU Input of PHY payload Output Ports Signal Type Optional int NO Port Name Description 2 Frame output of frame data in time domain Signal Type Optional complex NO Parameters Details: PHYFormat: specifies the type of PHY format Three formats (OQPSK_2000kchips/s, BPSK_600kchips/s, BPSK_300kchips/s) are supported PSDULength: specifies the PSDU payload length in bytes IdleInterval: specifies the idle interval between two bursts in chips SamplesPerChip: specifies the samples per chip Notes/Equations 1 This subnetwork completes ZigBee baseband signal source Both the 868/915MHz DSSS BPSK modulation and the 2450MHz DSSS O-QPSK modulation are supported The ZigBee_Source schematic is shown below: 17

19 2 Token number The port PSDU reads the the PSDU data The number of samples for the PSDU port per burst is calculated as:psdulength*8 It is equal to 160 by default 3 4 The port Frame produces IQ data sequences for one burst Each firing, FrameSamples tokens are produced at the port Frame FrameSamples=(( PSDULength*8)/BitsPerSymbol*ChipsPerSymbol+IdleIntrval)*SamplesPerChip, where the 32 refers to the number of bits for preamble, the first 8 refers to the number of bits for SDF field, the second 8 bits refers to the PHR BitsPerSymbol specifies the number of bits per symbol which equals to 1 for BPSK modulation and equals to 4 for O-QPSK modulation ChipsPerSymbol specifies the number of chips per symbol which equals to 15 for BPSK modulation and equals to 32 for O-QPSK modulation It is equal to 7056 by default The input of this subnetwork is PSDU data The schematic is split into two seperate parts, the half one on the top completes the DSSS BPSK modulation as: PPDU multiplexer, differential encoder, bit-to-chip mapping, BPSK modulation with raised cosine pulse shape The half one on the bottom completes the DSSS O-QPSK modulation as: PPDU multiplexer, bit-to-chip mapping, O-QPSK modulation with half sine pulse shape If the PHYFormat is selected to OQPSK_2000kbhips/s, the half one on the top will be inactive Otherwise, the half one on the bottom will be inactive The format of PPDU is PPDU format (zigbeebasever) For all PHYs except for the ASK PHY, the Preamble field shall be binary zeros The preamble field length is shown in Table 1 Table 1: Preamble field length 5 For all PHYs except for the ASK PHY, the SDF is an 8-bit field The SFD field length is shown in Table 2 The format of the SFD field is shown in Table 3 18

20 Table 2: SDF field length Table 3: Format of the SFD field(except for ASK) The modulation and spreading for 2450MHz O-QPSK is 2450MHz PHY specifications (zigbeebasever) The modulation and spreading for 868/915MHz BPSK is 868/915MHz BPSK PHY specifications (zigbeebasever) References 1 IEEE Std Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs) 19

21 ZigBee_FrameSync Part Categories: Sync Equalization (zigbeebasever) SystemVue - ZigBee Baseband Verification Library The models associated with this part are listed below To view detailed information on a model (description, parameters, equations, notes, etc), please click the appropriate link Model ZigBee_FrameSync (zigbeebasever) ZigBee_FrameSync Description ZigBee time and frequency synchronizer in time domain Description: ZigBee time and frequency synchronizer in time domain Domain: Untimed C++ Code Generation Support: NO Associated Parts: ZigBee FrameSync Part (zigbeebasever) Model Parameters Name Description Default Units Type Runtime Tunable PHYFormat the type of PHY format: OQPSK_2000kchips/s, BPSK_600kchips/s, BPSK_300kchips/s OQPSK_2000kchips/s 20 Enumeration NO PSDULength PSDU payload length in bytes 20 Integer NO IdleInterval idle interval between two burst in chips 100 Integer NO SamplesPerChip Samples per chip 4 Integer NO CorrBlockNum FreqSync SearchType TrackingRange Input Ports Number of oversampled samples in each sub correlation block Frequency estimation range selection: < 1/8 Symbol Rate, < 1/4 Symbol Rate, < 1/2 Symbol Rate, < Symbol Rate, < 2 Symbol Rate, < 4 Symbol Rate, < 8_Symbol Rate start a new timing and frequency synchronization search for every burst or not: Search every burst, Search+Track timing and frequency synchronization tracking range for the bursts except the first burst, valid when SearchType is Search_Track Port Name Description Signal Type Optional 1 Input Input signal complex NO Output Ports Port Name Description 32 Integer NO < 1/2 Symbol Rate Enumeration NO Search every burst Enumeration NO 20e-6 Float NO 2 Index number of input samples from real frame start to ideally aligned frame start Signal Type 3 DeltaF frequency offset detection real float NO 4 Corr correlation result real float NO Notes/Equations int Optional 1 This model is used to achieve burst synchronization and frequency offset estimation for ZigBee system Both 868/915MHz BPSK modulation and 2450MHz O-QPSK modulation are supported 2 Each firing, FrameSamples tokens are consumed at the input port, where FrameSamples refers to the number of samples of one burst including idle interval and calculated as:framesamples (zigbeebasever) It is equal to 7056 by default 1 token is produced at the output port Index 1 token is produced at the output port DeltaF FrameSamples tokens are produced at the output port Corr, where FrameSamples refers to the number of samples of one burst including idle interval and calculated as:framesamples (zigbeebasever) It is equal to 7056 by NO

22 default 3 The Preamble field is used by this model to obtain the start position of the burst by the correlation of the receiverd signal and the local preamble field The correlation is calculated as block correlations to suppress the carrier frequency deviation Firstly, the preamble field and the input signal is devided into subblocks and the number of samples in the subblock is specified by the parameter CorrBlockNum As shows below: In each subblock, the input signal is correlated with the local preamble field as Then the correlation is calcuated as: 4 5 When i is the start position of the burst, the correlation get maximum The frequency offset of the CorrBlockNum should be in the range (-π, π) When the parameter SearchType is set to "Search every burst", the search is done burst by burst in the whole burst period When the parameter SearchType is set to "Search+Track", the timing synchronization is divided into two steps: Initial searching and Tracking searching The initial searching is performed on the first burst, the same as when SearchType = Search every burst Then beginning with the second burst, tracking searching is employed Tracking searching will search the range [Index- TrackRange/2, Index+TrackRange/2] to get the timing synchronization index, where Index is the timing synchronization index gotten in the previous burst When the FreqSync is set to "<1/8 Symbol Rate", "<1/4 Symbol Rate" and "<1/2 Symbol Rate", the auto-correlation of the input signal is calculated to get the frequency offset as where the Index refers to the start position of the burst gotten from the above PreambleSamples refers to the number of samples of preamble field in one burst The CorrLength should be chosen to get the appropriate accuracy of the frequency offset The frequency offset is calculated as: where SamplingRate = SamplesPerChip*ChipRate ChipRate is equal to 2000kchips/s for 2450MHz O-QPSK modulation, equal to 600kchips/s for 915MHz BPSK modulation and equal to 300kchips/s for 868MHz BPSK modulation When the FreqSync is set to "<Symbol Rate", "<2 Symbol Rate", "<4 Symbol Rate" and "<8 Symbol Rate", the correlation between the input signal and local PN sequences is calculated to get the frequency offset The CorrBlockNum should not exceed the range of FreqSync For example, if the FreqSync is set to '< 8 Symbol Rate' which means the frequency offset of (-π, π) is for 1/8 symbol time The CorrBlockNum should be no larger than the number of samples in 1/8 symbol to restrain the frequency offset, otherwise the synchronization index may not be the actual position References 1 IEEE Std Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (WPANs) 21