05-May-2003 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [The ParthusCeva Ultra Wideband PHY proposal]

05-May-2003 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [The ParthusCeva Ultra Wideband PHY proposal] Date Submitted: [05 May, 2003] Source: [Michael Mc Laughlin, Vincent Ashe] Company [ParthusCeva Inc.] Address [32-34 Harcourt Street, Dublin 2, Ireland.] Voice:[ ], FAX: [-], Re: [IEEE P Alternate PHY Call For Proposals. 17 Jan 2003] Abstract: [Proposal for a a PHY] Purpose: [To allow the Task Group to evaluate the PHY proposed] Notice: This document has been prepared to assist the IEEE P 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 P Michael Mc Laughlin, ParthusCeva

The ParthusCeva PHY Proposal
05-May-2003 The ParthusCeva PHY Proposal Michael Mc Laughlin, ParthusCeva

Overview of Presentation
05-May-2003 Overview of Presentation PHY packet contents Coding DSSS Coding scheme - biorthogonal coding Ternary spreading codes FEC scheme - rate 4/6, 16 state convolutional coding Preamble Implementation Overview Performance Link margin Test results Data Throughput Complexity Michael Mc Laughlin, ParthusCeva

05-May-2003 Packet Contents Michael Mc Laughlin, ParthusCeva

doc.: IEEE 802.15-<doc#>
<month year> doc.: IEEE <doc#> 05-May-2003 The coding scheme 64 biorthogonal signals [Proakis1] 64 signals from 32 orthogonal sequences Ternary sequences chosen for their auto-correlation properties Code constructed from binary Golay-Hadamard sequences Michael Mc Laughlin, ParthusCeva <author>, <company>

Creating Orthogonal Ternary Sequences
05-May-2003 Creating Orthogonal Ternary Sequences Take a matrix of binary orthogonal sequences, in our case we used Golay-Hadamard sequences Add any two rows to get a ternary sequence Sum of any other two rows is orthogonal to this Continue till all the rows are used Repeat but subtracting instead of adding Michael Mc Laughlin, ParthusCeva

Finding good Ternary Golay Hadarmard codes
05-May-2003 Finding good Ternary Golay Hadarmard codes Large superset of orthogonal sequence sets to test Define aperiodic autocorrelation merit factor (aamf) as the ratio of the peak power of the autocorrelation function to the mean power of the offpeak values divided by the length of the code. Random walk used to find set with best aamf Michael Mc Laughlin, ParthusCeva

05-May-2003 Code comparison Length 32 code chosen for aamf and best matching with bit rates. Michael Mc Laughlin, ParthusCeva

Sample rate and pulse repetition frequency
05-May-2003 Sample rate and pulse repetition frequency Signal bandwidth chosen is 3.8GHz to 7.7GHz Sampling rate chosen is 7.7Ghz 32 chips per codeword, 4 bits / symbol (6 bits less 2 for convolutional code) Michael Mc Laughlin, ParthusCeva

05-May-2003 FEC scheme A rate (rate 4/6) convolutional code was chosen for the FEC. [Proakis2] Very low complexity 16 state code, constraint length 2, Octal generators 27, 75, 72. Each of 16 states can transition to any other state, outputting 16 of 64 possible codewords. Provides 3dB of gain over uncoded errors at a cost of 50% higher bit rate Michael Mc Laughlin, ParthusCeva

Convolutional coder + + + 05-May-2003 Map every 6 bits to one of 64
biorthogonal codewords + + 2 bits in Michael Mc Laughlin, ParthusCeva

05-May-2003 Preamble Sequence Michael Mc Laughlin, ParthusCeva

05-May-2003 PAC properties Because of the perfect autocorrelation property, the channel impulse response can be obtained in the receiver by correlating with the sequence and averaging the results. Because the sequence consists of mostly 1, -1 with a small number of zerosm correlation can be economically implemented. (a length 553 PAC has 24 0’s) Michael Mc Laughlin, ParthusCeva

05-May-2003 Preamble properties Very good detect rate and false alarm probability. Pfa and Pmd < 10-4 for CM1 to CM4 test suite at 10 metres. Different length sequences means other piconets won’t trigger detection i.e. Pfa still < 10-3 for a different piconets PACn, even at 0.3m separation. Preamble length varies from ~5s to ~15s depending on the bit rate. Lower bitrates use longer preambles (Longer distances need more training time) Michael Mc Laughlin, ParthusCeva

05-May-2003 PHY Header The PHY header is sent at an uncoded 45Mbps rate, but with no convolutional coding. It is repeated 3 times. The PHY header contents are the same as i.e. Two octets with the Data rate, number of payload bits and scrambler seed. Michael Mc Laughlin, ParthusCeva

Scrambler/Descrambler
05-May-2003 Scrambler/Descrambler It is proposed that the PHY uses the same scrambler and descrambler as used by IEEE Michael Mc Laughlin, ParthusCeva

Typical Tx/Rx configuration
05-May-2003 Typical Tx/Rx configuration Antenna Single Chip Possible Output data at Mbps Band Reject Filter Channel Matched filter (Rake Receiver) Band Pass Filter* A/D 7.7GHz, 1 bit Switch / Hybrid LNA Correlator Bank Viterbi Decoder Descramble Mchips/sec 8-240M symbols/sec Input data at Mbps Band Pass Filter Band Reject Filter Chip to Pulse Generator Code Generator Convolutional encoder Scramble * Can be avoided with good LNA dynamic range Michael Mc Laughlin, ParthusCeva

Possible RF front end configuration
05-May-2003 Possible RF front end configuration Total Noise Figure = 7.0dB NF= 0.2dB (input referred) NF= 2.0dB NF= 4.0dB BP Filter* Fine Filter LNA To Rx NF= 0.8dB Tx/Rx switch / hybrid Filter From Tx * Can be avoided with good LNA dynamic range Michael Mc Laughlin, ParthusCeva

Matched Filter configuration
05-May-2003 Matched Filter configuration Cn 4 1 Di Cn+N Di-N Cn+1 4 1 Di-1 Cn+N+1 Di-N-1 ….. ….. 4x 4x 4x 4x 4 4 4 4 ….. 4 bit adder 4x 4x + 5 bit adder + ….. ….. Michael Mc Laughlin, ParthusCeva

Matched Filter configuration
05-May-2003 Matched Filter configuration Structure repeated 16 times e.g. a 500 tap filter with 4 bit coefficients would have 500 x 16 x 4 AND gates in first stage Calculates 16 outputs in parallel, each runs at 480MHz. Multiplier is 4 AND gates. First adder stage is 4 OR gates. Very little performance loss. (0dB for CM1-3, 0.23dB for CM4). Coefficients are pre-processed to remove smallest if two clash. Michael Mc Laughlin, ParthusCeva

05-May-2003 Matched filter 560 tap filter takes 150k gates or 0.9 sq mm in 0.13 standard cell CMOS Power consumption = 220mW Matched filter acts as correlator during training phase. All simulations were carried out with this filter/correlator structure Michael Mc Laughlin, ParthusCeva

05-May-2003 Michael Mc Laughlin, ParthusCeva

Distance achieved for mean packet error rate = 8%
05-May-2003 Distance achieved for mean packet error rate = 8% Michael Mc Laughlin, ParthusCeva

Distance achieved for at worst packet error rate = 8%
05-May-2003 Distance achieved for at worst packet error rate = 8% Michael Mc Laughlin, ParthusCeva

Average distance at 8% PER
05-May-2003 Average distance at 8% PER Michael Mc Laughlin, ParthusCeva

05-May-2003 480 Mbps average PER Michael Mc Laughlin, ParthusCeva

Adjacent Channel Interferers: Single uncoordinated piconet
05-May-2003 Adjacent Channel Interferers: Single uncoordinated piconet Tests were done with reference links using channel models 1-4, channels 1-5 with shadowing removed. Interferers used channels 6-10 of Channel models 1 to 4. To allow some error margin, the distances to the reference receivers were 5m, 2m and 1.5m. For each channel model, at each distance, the mean PER for all 100 tests was calculated. (5 x 4 x 5) Michael Mc Laughlin, ParthusCeva

120 Mbps with single adjacent interferer
05-May-2003 120 Mbps with single adjacent interferer Single uncoordinated piconet, Reference Link 120Mbps at 5m, cm1-4 -0.5 -1 -1.5 0 average PER 8% PER -2 channel model 1 channel model 2 1 channel model 3 log -2.5 channel model 4 -3 -3.5 -4 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Interferer Distance (m) Michael Mc Laughlin, ParthusCeva

240Mbps with single adjacent interferer
05-May-2003 240Mbps with single adjacent interferer Single uncoordinated piconet, Reference Link 240Mbps at 2m, cm1-4 -0.5 -1 -1.5 8% PER log10 Average PER channel model 1 channel model 2 -2 channel model 3 channel model 4 -2.5 -3 -3.5 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 Interferer Distance (m) Michael Mc Laughlin, ParthusCeva

480Mbps with single adjacent interferer
05-May-2003 480Mbps with single adjacent interferer Michael Mc Laughlin, ParthusCeva

Two adjacent channel interferers
05-May-2003 Two adjacent channel interferers Tests were done with reference links using channel models 1-4, channels 1-5 with shadowing removed. Adjacent channel interferers used a freespace channel To allow some error margin, the distances to the reference receivers were 5m, 2m and 1.5m. For each channel model, at each distance, the mean PER over the 5 channels is plotted. Michael Mc Laughlin, ParthusCeva

120Mbps - Two free space interferers
05-May-2003 120Mbps - Two free space interferers Michael Mc Laughlin, ParthusCeva

120Mbps - Three free space interferers
05-May-2003 120Mbps - Three free space interferers Michael Mc Laughlin, ParthusCeva

05-May-2003 More interferers What matters is the total interference power, very little effect due to delay spread of the interfering channels. 2 interferers have 3dB more power than 1 which translates to 50% worse distance performance. 3 interferers have 1.76dB more power than 2 which translates to 22% worse distance performance. 4 interferers have 1.76dB more power than 3 which translates to 15% worse distance performance. Michael Mc Laughlin, ParthusCeva

Co-channel interference
05-May-2003 Co-channel interference Different piconets use exactly the same data mode codes as each other. Separation is achieved mainly because a different piconet will have a different impulse response and thus will not correlate with the matched filter which has been trained for the piconet of interest. For this reason, co-channel data mode interference has the same effect as adjacent channel interference. Training to the preamble will be affected more markedly by co-channel interference. Difficult to simulate. Michael Mc Laughlin, ParthusCeva

05-May-2003 Co existence Out of band signal (< 3.85GHz and >10.6GHz) are always filtered out. Any desired in band energy can be filtered out, with minimal effect on performance because the whole band is used to transfer data. Only adverse effect is the transmit power reduction (e.g. Dropping 400MHz for a loses <0.5dB) Michael Mc Laughlin, ParthusCeva

Interference and susceptibility
05-May-2003 Interference and susceptibility As for co existence, out of band signal are always filtered out. Again, any desired in band energy can be filtered out, with minimal effect on performance because the whole band is used to transfer data. Only adverse effect is the receive power reduction (e.g. Dropping 400MHz for a loses <0.5dB), its just a part of the channel. Michael Mc Laughlin, ParthusCeva

PHY-SAP Data Throughput
05-May-2003 PHY-SAP Data Throughput At higher bit rates, a 1024 byte frame is very short. The channel will be stationery for more than one frame so it is possible to send multiple frames for each preamble. Michael Mc Laughlin, ParthusCeva

05-May-2003 Scalable solution Possible to improve distance achieved by increasing coder complexity. (Decoder used here <15k gates) Mbps. PHY power consumption/gate count changes little over range Short range solution with much smaller matched filter for smaller delay spread Michael Mc Laughlin, ParthusCeva

Complexity - Area/Gate count, Power consumption
05-May-2003 Complexity - Area/Gate count, Power consumption Michael Mc Laughlin, ParthusCeva

Self evaluation : General Criteria
05-May-2003 Self evaluation : General Criteria Michael Mc Laughlin, ParthusCeva

Self evaluation : PHY protocol
05-May-2003 Self evaluation : PHY protocol Michael Mc Laughlin, ParthusCeva

Self evaluation : MAC enhancements
05-May-2003 Self evaluation : MAC enhancements Michael Mc Laughlin, ParthusCeva

} Summary of advantages Ternary spreading codes
05-May-2003 Summary of advantages Ternary spreading codes Better auto-correlation properties Perfect PAC training sequence Simple RF section 1 bit A/D converter No AGC required No mixers required Long matched filter possible 4 bit coefficients 1 bit data no multipliers } Low cost Low power consumption Low Noise figure Michael Mc Laughlin, ParthusCeva

05-May-2003 Backup Slides Michael Mc Laughlin, ParthusCeva

Ternary orthogonal sequences
05-May-2003 Ternary orthogonal sequences From any base set of 32 orthogonal binary signals, can generate 32C16 sets of 32 orthogonal ternary sequences. Generate by adding and subtracting any 16 pairs. Generally, if the base set has good correlation properties, so will a generated set. Michael Mc Laughlin, ParthusCeva

05-May-2003 Good base binary set Base set is a set of binary Golay-Hadamard sequences Take a binary Golay complementary pair. s116=[ ]; s216=[ ]; if A=circulant(s116) and B=circulant(s216) and G32= A B BT -AT then G32 is a Hadamard matrix. [Seberry] This type has particularly good correlation properties[Seberry] Detector can use the Fast Hadamard Transform Michael Mc Laughlin, ParthusCeva

Creating Orthogonal Ternary Sequences
05-May-2003 Creating Orthogonal Ternary Sequences Take a matrix of binary orthogonal sequences Add any two rows to get a ternary sequence Sum of any other two rows is orthogonal to this Continue till all the rows are used Repeat but subtracting instead of adding Michael Mc Laughlin, ParthusCeva

Orthogonal Ternary Example
05-May-2003 Orthogonal Ternary Example E.g pairing 1 with 3 and 2 with 4 gives this orthogonal matrix Michael Mc Laughlin, ParthusCeva

Finding good Ternary Golay Hadarmard codes
05-May-2003 Finding good Ternary Golay Hadarmard codes Large superset of orthogonal sequence sets to test Define aperiodic autocorrelation merit factor (aamf) as the ratio of the peak power of the autocorrelation function to the mean power of the offpeak values divided by the length of the code. Random walk used to find set with best aamf Michael Mc Laughlin, ParthusCeva

05-May-2003 Code comparison Length 32 code chosen for aamf and best matching with bit rates. Michael Mc Laughlin, ParthusCeva

Ternary Orthogonal Length 32 Code Set
05-May-2003 Ternary Orthogonal Length 32 Code Set Michael Mc Laughlin, ParthusCeva

Matlab Code to generate PAC sequences
05-May-2003 Matlab Code to generate PAC sequences % function phi=ipatov(nu,multiplier,mul2); % % Generate a length nu, ternary perfect periodic autocorrelation sequence % using Singer Cyclic Difference Sets e.g. (553, 24, 1) function phi=ipatov(nu,multiplier,mul2); if nargin==1 multiplier=1; mul2=-1; end % multipliers 1,-1 are most commonly good if nargin==2 mul2=-1; end % multipliers 1,-1 are most commonly good phi=0; if gcd(nu,multiplier)>1; % must not be a common divisor of nu return; end if gcd(nu,mul2)>1; % must not be a common divisor of nu switch nu case % nu=7;k=3;lamda=1; D=[ ]; case 13 nu=13;k=4;lamda=1; D=1+[ ]; case 21 nu=21;k=5;lamda=1; D=[3,6,7,12,14]; case 31 nu=31;k=6;lamda=1; D=[ ]; case 57 nu=57;k=8;lamda=1; D=[ ]; case % multipliers 1,5 gives perfect ternary nu=63;k=31;lamda=15; D=1+[ ]; case 73 nu=73;k=9;lamda=1; D=[1, 2, 4, 8, 16, 32, 37, 55, 64]; % P73 case 91 nu=91;k=10;lamda=1; D= [ ]; % case 133 nu=133;k=12;lamda=1; D=[ ]; case 183 nu=183;k=14;lamda=1; D=[ ]; case 273 nu=272;k=17;lamda=1; D=[ ]; case 307 nu=307;k=18;lamda=1; D=[ ]; case 341 nu=341;k=85;lamda=21; % 1,5 gives a perfect ternary sequence D= [ 335 ]; case 364 nu=364;k=121;lamda=40; % 1,5 gives a perfect ternary sequence D=[ 360 ]; case 381 nu=381;k=20;lamda=1; D=1+[ ]; case % 1,3 gives a perfect ternary sequence nu=511;k=255;lamda=127; D=[ ]; case 553 nu=553;k=24;lamda=1; D=[ ]; case 651 nu=651;k=26;lamda=1; D=[ ]; case 757 nu=757;k=28;lamda=1; D=[ ]; case 781 nu=781;k=156;lamda=31; % 1,2 gives a perfect ternary sequence D=1+[ ]; case 871 nu=871;k=30;lamda=1; D=[ ]; case 993 nu=993;k=32;lamda=1; D=1+[ ]; case 1057 nu=1057;k=33;lamda=1; D=[ ]; case 1407 nu=1407;k=38;lamda=1; D=1+[ ]; case 1723 nu=1723;k=42;lamda=1; D=[ ]; otherwise return end % end switch D=sort(mod(D*multiplier,nu)); % transform to new difference set. while any(D==0) D=mod(D+1,nu); Dhat=sort(mod(D*mul2,nu)); % transform to another new difference set while any(Dhat==0) Dhat=mod(Dhat+1,nu); ; Xd=zeros(1,nu); Xdhat=Xd; Xd(D)=1; Xdhat(Dhat)=1; phi=xcorr([Xd Xd],[Xdhat])-lamda; phi=round(phi(2*nu+1:2*nu+nu)); % phi is the ternary sequence if nargout==0 plot(xcorr(phi,[phi phi phi])) Michael Mc Laughlin, ParthusCeva

05-May-2003 References [Proakis1] John G. Proakis, Digital Communications 2nd edition. McGraw Hill. pp [Proakis2] John G. Proakis, Digital Communications 2nd edition. McGraw Hill. pp [Seberry et al] J. Seberry, B.J. Wysocki and T.A. Wysocki, Golay Sequences for DS CDMA Applications, University of Wollongong [Ipatov] V. P. Ipatov, “Ternary sequences with ideal autocorrelation properties” Radio Eng. Electron. Phys., vol. 24, pp , Oct [Høholdt et al] Tom Høholdt and Jørn Justesen, “Ternary sequences with Perfect Periodic Autocorrelation”, IEEE Transactions on information theory. Michael Mc Laughlin, ParthusCeva

05-May-2003 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [The ParthusCeva Ultra Wideband PHY proposal]

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05-May-2003 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [The ParthusCeva Ultra Wideband PHY proposal]

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Presentation on theme: "05-May-2003 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [The ParthusCeva Ultra Wideband PHY proposal]"— Presentation transcript:

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