function lc = lcDefSDSL_sym
%% ===========================================================================
% lcDefSDSL_sym - Sets up the lincode description structure for symmetric SDSL
%
% Returns:       lc	The linecode structure
%
% References:	
%    Draft ETSI TS 101524-2 V1.1.1 (2000-05)
%    Chen W., "DSL simulation techniques and standards development
%    for DSL systems"
%    Starr T., J. Cioffi, P. Silverman "Understanding DSL technology", 1999
%    The xDSL simulation tool manual, FTW 2000
%% ===========================================================================

%% ===========================================================================
% Copyright (C) 2000-2009 by Forschungszentrum Telekommunikation Wien, Austria;
%                                                     All rights reserved. 
% Project       : FTW's xDSLsimu
% Author(s)     : Tomas Nordstrom (Tomas.Nordstrom@FTW.at)
%               : Gernot Schmid (schmid@ftw.at
%% ===========================================================================
% Change History
%      2000-03-23 (GS)   Created
%      2000-04-12 (GS)   Receive filter extensions
%      2000-07-06 (ToNo) Modified the way we define reqSNR
%      2000-07-13 (GS)   Extensions for asymmetric SDSL
%      2000-09-27 (GS)	 Cleaning up for release
%      2003-12-16 (ToNo) Split background noise into bgNoise and modemNoise
%      2003-12-16 (ToNo) Changed default to include a xtalk_margin of 6 dB
%      2008-08-28 (ToNo) Introduced consistent naming (pam -> mod; bpsym)
%% ===========================================================================

lc.name           	  = 'SDSL-sym';

% Default Parameter values

lc.param.Px               = [0  2048e3 1e99; 13.5 14.5 14.5;]; %dBm TX power template 
lc.param.signal_margin    = 0;
lc.param.codingGain       = 5.1;  
lc.param.xtalk_margin     = 6;
lc.param.refSNR           = 9.8;
lc.param.SNRloss          = 1.6;      % 1.6; 2.1 for loop 6 (with bridge taps

% Calculate the req SNR [Starr]:
% M  = 2^(constellation-1);  % UC coding reduces the size by one
% Pe = 1e-7;
% ei = erfinv(1-Pe./(1-1./M));
% lc.param.reqSNR           = 10*log10((M.*M-1).*2./3.*ei.^2);

% [Chen p 524] or [ETSI 994t40a0] gives
lc.param.reqSNR           = 27.71 ...
    - lc.param.codingGain + lc.param.SNRloss;

% Param digital
lc.param.mod.bpsym        = 3;     % Bits per symbol (constellation-1)
lc.param.mod.brate.rate   = 512e3; % Bitrate in bit per sec. (excl. overhead)
lc.param.mod.brate.ohead  = 8e3;   % Datarate overhead
lc.param.mod.filterorder  = 6;     % Transmit filter order (butterworth)  
lc.param.mod.filterratio  = 0.5;   % f3dB/fsym ratio 
% Scaling factor template, only used for the legacy description (_RC)
lc.param.mod.k	          = [0  2048e3 2304e3+1; 7.86 9.90 9.90;];   
lc.param.mod.highpass3dBf = 5e3;   % Coupling transformer cutoff frequency
lc.param.mod.floorf       = 1.5e6; % When the PSD start being flat 
% Using fzero(@(x) 10*log10(1e3* 0.5683e-4 * x.^(-1.5))+110,5e6)
% we find that a better value for floorf would be 3.1846e+06

% Optional receive filter (Butterworth is assumed)
lc.param.mod.recfilterorder.up = 6;
lc.param.mod.recfilterorder.dn = 6;
fsymb = ((lc.param.mod.brate.rate + lc.param.mod.brate.ohead) ...
         /lc.param.mod.bpsym); 
lc.param.mod.recfilter3dBf.up  = fsymb *lc.param.mod.filterratio; 
lc.param.mod.recfilter3dBf.dn  = lc.param.mod.recfilter3dBf.up;

lc.param.SNRMax           = 100;    % Maximum SNR usable [Chen p.524] 
lc.param.efficiencyLoss   = 0;      % General efficiency loss factor
                                    % SDSL uses SNRloss instead

lc.param.modemNoise.LT    = '-140'; % Modem noise at LT (dBm/Hz)
lc.param.modemNoise.NT    = '-140'; % Modem noise at NT (dBm/Hz)

lc.calcRate 		  = 'calcResultSDSL';
lc.lcPrint 		  = 'lcPrintSDSL';