BPSK.zip_MIMO-BPSK_bpsk MIMO_mimo + bpsk

Ce code M simule modulation DBPSK et Barker code d'�talement sur une parfaite synchronisation 802.11b lien. Il calcule le taux de REC � chaque Es / Non et placettes du r�sultat. ********************************************** EsNoRange = 0:2:10; % Range of noice levels to calculate BER NumPackets = 2; PacketSizeBytes = 1024; PacketSizeBits = PacketSizeBytes*8; % Ignore preamble and sync bits clear BERResults; clear ErrorResults; % Spreading parameters Barker = [1 -1 1 1 -1 1 1 1 -1 -1 -1]'; % Barker sequence SpreadingRate = length(Barker); % Spreading rate % Upsampling rate SamplesPerChip=8; % Filter order and coefficients - root raised cosine FilterOrder = 40; % Set to multiple of SamplesPerChip to make delay calculation easy h = firrcos(FilterOrder,7e6,.7,88e6,'rolloff','sqrt',FilterOrder/2,kaiser(FilterOrder+1,1)); BitDelay = 1; ChipDelayAdd = 6; NumEsNos = length(EsNoRange); ErrorResults = zeros(1,NumEsNos); disp(' ');disp('Start Simulation'); for EsNoIndex = 1:NumEsNos EsNo = EsNoRange(EsNoIndex); disp(['Simulating: Es/No=' num2str(EsNo) 'dB']); SNR = EsNo+10*log10(1/SpreadingRate)+10*log10(1/SamplesPerChip); % Initialize system and simulation measurements state % Bits TotalBits = false; % Bit count for BER calculation ErrorBits = false; % Error count for BER calculation LastTxSymbol = 1; % Set DBPSK Modulator state LastRxSymbol = 1; % Set DBPSK Demodulator state % Filters Rx_chips_delayed_store = zeros(ChipDelayAdd,1); Tx_bits_delayed_store = false(BitDelay,1); Tx_Filter_State = h(1:end-1); % Fill filter with a +1 symbol Rx_Filter_State = h(1:end-1); % Fill filter with a +1 symbol % Main simulation loop % Each packet is transmitted, and the recieved bits compared with the % transmitted bits to calculate the BER. for Packet = 1:NumPackets % Construct frame of bits rand('state', 0); Tx_bits = rand(PacketSizeBits,1)>.5; % Random bits % Modulate Tx_bits_bp = (1-2*Tx_bits); % Convert to bipolar 0,1 --> 1, -1 Tx_symbols = LastTxSymbol*cumprod(Tx_bits_bp); % New DBPSK symbol = previous * 1 or -1 LastTxSymbol = Tx_symbols(end); % Store modulator state (last symbol) % Spread symbols with Barker code, upsampling by spreading rate Tx_chips = reshape(Barker*Tx_symbols',[],1); % Multiply by barker and reshape to a columm Tx_chips = complex(Tx_chips); % Make complex to ensure correct baseband transmission % Upsample chips by SamplesPerChip factor Tx_samples = zeros(length(Tx_chips)*SamplesPerChip,1); % Create empty Tx_samples Tx_samples(1:SamplesPerChip:end,1) = sqrt(SamplesPerChip)*Tx_chips; % Normalize power due to upsampling % Tx Filter [Tx_samples_filtered,Tx_Filter_State] = filter(h,1,Tx_samples,Tx_Filter_State); % Filter Tx_samples_filtered = Tx_samples_filtered*2.495; % Set output power to 1W var(Tx_samples_filtered); % Calculate Tx signal power, view by removing ';' % Transmit though AWGN Channel assuming 0dBW input power (check % with line above) Rx_samples_unfiltered = awgn(Tx_samples_filtered,SNR,0,0); % Rx Filter [Rx_samples_filtered,Rx_Filter_State] = filter(h,1,Rx_samples_unfiltered,Rx_Filter_State); % Downsample - sample chips Rx_chips = Rx_samples_filtered(1:SamplesPerChip:end); % Add 1 chip delay to move signal to 11 chip boundary Rx_chips_delayed = [Rx_chips_delayed_store; Rx_chips(1:end-ChipDelayAdd)]; Rx_chips_delayed_store = Rx_chips((end-ChipDelayAdd+1):end); % Store delayed chips % Despread - sample symbol Rx_symbols = Barker'*reshape(Rx_chips_delayed,SpreadingRate,PacketSizeBits); % Multiply by Barker Rx_symbols = Rx_symbols(:)/SpreadingRate; % Make a column and normalize % Demodulate Rx_symbols_plus_last = [LastRxSymbol; Rx_symbols]; Rx_symbols_plus_last_mult = Rx_symbols_plus_last(1:end-1).*conj(Rx_symbols_plus_last(2:end)); Rx_bits = Rx_symbols_plus_last_mult < 0; LastRxSymbol = Rx_symbols(end); % Demodulator state % Calculate BER % Add BitDelay to Tx signal to align with Rx signal Tx_bits_delayed = [Tx_bits_delayed_store; Tx_bits(1:end-BitDelay)]; Tx_bits_delayed_store = Tx_bits(end-BitDelay+1:end); % Store delayed symbol if Packet==1 % Ignore delayed bits on first packet TotalBits = TotalBits+length(Rx_bits)-BitDelay; ErrorBits = ErrorBits+sum(Tx_bits_delayed(BitDelay+1:end)~=Rx_bits(BitDelay+1:end)); else TotalBits = TotalBits+length(Rx_bits); % Calculate total bits ErrorBits = ErrorBits+sum(Tx_bits_delayed~=Rx_bits); % Compare Tx and Rx bits end end ErrorResults(EsNoIndex) = ErrorBits; %error bits end BERResults = ErrorResults/TotalBits; % Calculate BER semilogy(EsNoRange,BERResults,'*-'); grid; title('802.11b 1Mbps DBPSK BER'); ylabel('BER') xlabel('Es/No (dB)');