A list,
The core problem of cooperative communication is the cooperation protocol of relay nodes. There are two basic relay cooperation modes: amplification and retransmission (AF) and decoded and retransmitted (DF). The research of other cooperation protocols is almost based on these two fixed relay protocols. This paper verifies the improvement of communication through MATLAB simulation, analyzes the bit error rate and diversity gain of AF and DF under different channels and different SNR, and studies the actual performance and main problems faced by the two.
Ii. Source code
% multi - hop, the main program tic % -- -- -- -- -- -- -- -- -- -- -- -- -- -- % Set the Parameters nr_of_iterations =1000;
SNR = [- 10:1:10];
use_direct_link = 1;
use_relay = 1;
global statistic;
statistic = generate_statistic_structure;
global signal;
signal = generate_signal_structure;
signal(1).nr_of_bits = 2^10;
signal.modulation_type = 'BPSK';% ’BPSK’, ’QPSK’
calculate_signal_parameter;
channel = generate_channel_structure;
channel(1).attenuation(1).pattern = 'Rayleigh'; Rayleigh channel (' % 'no,' '1).attenuation(1).block_length = 1;
channel(2) = channel(1);
channel(3) = channel(1);
channel(4) = channel(1);
channel(5) = channel(1);
channel(6) = channel(1);
channel(7) = channel(1);
channel(8) = channel(1);
channel(9) = channel(1);
channel(10) = channel(1);
channel(11) = channel(1);
channel(12) = channel(1);
rx = generate_rx_structure;
rx(1).combining_type = 'ERC'; % 'ERC', 'FRC', 'SNRC', 'ESNRC', 'MRC' rx (1).sd_weight = 3; % used for 'FRC'
global relay;
relay = generate_relay_structure;
relay(1).mode = 'DAF'; % 'AAF,' and 'DAF' relay. Magic_genie =0;
relay(1).rx(1) = rx(1); % same beahaviour
channel(1).attenuation.distance = 1;
channel(2).attenuation.distance = 0.5;
channel(3).attenuation.distance = 0.5;
% ----------------
% Start Simulation
BER = zeros(size(SNR));
for iSNR = 1:size(SNR,2)% returns the size of the dimension of SNR specified by scalar 2
disp(['progress: ',int2str(iSNR),'/',int2str(size(SNR,2))]) % Convert integer to string
%%%%%%%%%%%%%%%%%%%%%%
channel(1).noise(1).SNR = SNR(iSNR); % iSNR ??????
channel(2).noise(1).SNR = SNR(iSNR);
channel(3).noise(1).SNR = SNR(iSNR);
for it = 1:nr_of_iterations; % -------------- % Reset receiver rx = rx_reset(rx); relay.rx = rx_reset(relay.rx); % -- -- -- -- -- -- -- -- -- -- - %Direct link
if (use_direct_link == 1)
[channel(1), rx] = add_channel_effect(channel(1), rx,...
signal.symbol_sequence);
rx = rx_correct_phaseshift(rx, channel(1).attenuation.phi); End % ------------ Trunk transmission ---------------if (use_relay == 1) % use relay collaboration % ---------- only1--------- % Sender to relay [channel(2), relay.rx] = add_channel_effect(channel(2),relay.rx, signal.symbol_sequence);
relay = prepare_relay2send(relay,channel(2));
% Relay to destination
[channel(3), rx] = add_channel_effect(channel(3), rx,relay.signal2send);
% [received_symbol,signal.received_bit_sequence]=rx_combine(rx,channel,use_relay);
switch relay.mode
% Correct phaseshift
case 'AAF'
rx = rx_correct_phaseshift(rx,...
channel(3).attenuation.phi + channel(2).attenuation.phi);
case 'DAF'
rx = rx_correct_phaseshift(rx,channel(3).attenuation.phi);
end
end
% Receiver
[received_symbol, signal.received_bit_sequence] = rx_combine(rx, channel(1),channel(3), use_relay);
BER(iSNR) = BER(iSNR) + sum(not(signal.received_bit_sequence == signal.bit_sequence));
if (BER(iSNR) > 10000)
% Stop iterate
break;
end
end % Iteration
if (BER(iSNR)<100)
warning(['Result might not be precise when SNR equal ',num2str(SNR(iSNR))])
end
BER(iSNR) = BER(iSNR) ./ it ./ signal.nr_of_bits;
end
% ---------------Present the result of the simulation---------------------
txt_distance = [' - distance: '. num2str(channel(1).attenuation.distance), ':'. num2str(channel(2).attenuation.distance), ':'. num2str(channel(3).attenuation.distance)];
%txt_distance="'; if (use_relay == 1) if (relay.magic_genie == 1) txt_genie = ' - Magic Genie';
else
txt_genie = "'; end txt_combining = [' - combining: ', rx(1).combining_type];
switch rx(1).combining_type
case 'FRC'
txt_combining = [txt_combining, ' '. num2str(rx(1).sd_weight),'1']; %Convert number to string
end
add2statistic(SNR,BER,[signal.modulation_type, The '-',relay.mode, txt_combining,', '.'two-hop'])
else
switch channel(1).attenuation.pattern
case 'no'
txt_fading = ' - no fading';
otherwise
txt_fading = ' - Rayleigh fading';
end
add2statistic(SNR,BER,[signal.modulation_type, The '-',relay.mode, txt_combining,', '.'two-hop'])End %--------------- multi-hop emulation -----------%channel(1).attenuation.distance = 1;
channel(2).attenuation.distance = 1/3;
channel(3).attenuation.distance = 1/3;
channel(4).attenuation.distance = 1/3;
% ----------------
% Start Simulation
BER = zeros(size(SNR));
for iSNR = 1:size(SNR,2)% returns the size of the dimension of SNR specified by scalar 2
disp(['progress: ',int2str(iSNR),'/',int2str(size(SNR,2))]) % Convert integer to string
%%%%%%%%%%%%%%%%%%%%%%
channel(1).noise(1).SNR = SNR(iSNR); % iSNR ??????
channel(2).noise(1).SNR = SNR(iSNR);
channel(3).noise(1).SNR = SNR(iSNR);
channel(4).noise(1).SNR = SNR(iSNR);
for it = 1:nr_of_iterations; % -------------- % Reset receiver rx = rx_reset(rx); relay.rx = rx_reset(relay.rx); % -- -- -- -- -- -- -- -- -- -- - %Direct link
if (use_direct_link == 1)
[channel(1), rx] = add_channel_effect(channel(1), rx,...
signal.symbol_sequence);
rx = rx_correct_phaseshift(rx, channel(1).attenuation.phi); End % ---- Trunk transmission -----%if (use_relay == 1)
% Sender to relay
[channel(2), relay.rx] = add_channel_effect(channel(2),relay.rx, signal.symbol_sequence);
relay = prepare_relay2send(relay,channel(2));% ??this function
%relay1 to Relay2
[channel(3), relay.rx]=add_channel_effect(channel(3),relay.rx, relay.signal2send);
relay=prepare_relay2send(relay,channel(3));
%relay2 to destination
[channel(4),rx]=add_channel_effect(channel(4),rx,relay.signal2send);
switch relay.mode
% Correct phaseshift
case 'AAF'
rx = rx_correct_phaseshift(rx,...
channel(2).attenuation.phi + channel(3).attenuation.phi+ channel(4).attenuation.phi);
case 'DAF'
rx = rx_correct_phaseshift(rx,channel(4).attenuation.phi);
end
end
% Receiver
[received_symbol, signal.received_bit_sequence] = rx_combine(rx, channel(1),channel(4), use_relay);
BER(iSNR) = BER(iSNR) + sum(not(signal.received_bit_sequence == signal.bit_sequence));
if (BER(iSNR) > 10000)
% Stop iterate
break;
end
end % Iteration
if (BER(iSNR)<100)
warning(['Result might not be precise when SNR equal '. num2str(SNR(iSNR))])
end
BER(iSNR) = BER(iSNR) ./ it ./ signal.nr_of_bits;
end
% ---------------Present the result of the simulation---------------------
txt_distance = [' - distance: '. num2str(channel(2).attenuation.distance), ':'. num2str(channel(3).attenuation.distance), ':'. num2str(channel(4).attenuation.distance)];
%txt_distance="'; if (use_relay == 1) if (relay.magic_genie == 1) txt_genie = ' - Magic Genie';
else
txt_genie = "'; end txt_combining = [' - combining: ', rx(1).combining_type];
Copy the code3. Operation results
Fourth, note
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