Notes

Exp 8
client:
import socket

IP = socket.gethostbyname(socket.gethostname())
PORT = 4455
ADDR = (IP, PORT)
FORMAT = "utf-8"
SIZE = 1024

def main():
""" Staring a TCP socket. """
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

""" Connecting to the server. """
client.connect(ADDR)

""" Opening and reading the file data. """
file = open("data/yt.txt", "r")
data = file.read()

""" Sending the filename to the server. """
client.send("yt.txt".encode(FORMAT))
msg = client.recv(SIZE).decode(FORMAT)
print(f"[SERVER]: {msg}")

""" Sending the file data to the server. """
client.send(data.encode(FORMAT))
msg = client.recv(SIZE).decode(FORMAT)
print(f"[SERVER]: {msg}")

""" Closing the file. """
file.close()

""" Closing the connection from the server. """
client.close()


if __name__ == "__main__":
main()

server:
import socket

IP = socket.gethostbyname(socket.gethostname())
PORT = 4455
ADDR = (IP, PORT)
SIZE = 1024
FORMAT = "utf-8"

def main():
print("[STARTING] Server is starting.")
""" Staring a TCP socket. """
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

""" Bind the IP and PORT to the server. """
server.bind(ADDR)

""" Server is listening, i.e., server is now waiting for the client to connected. """
server.listen()
print("[LISTENING] Server is listening.")

while True:
""" Server has accepted the connection from the client. """
conn, addr = server.accept()
print(f"[NEW CONNECTION] {addr} connected.")

""" Receiving the filename from the client. """
filename = conn.recv(SIZE).decode(FORMAT)
print(f"[RECV] Receiving the filename.")
file = open(filename, "w")
conn.send("Filename received.".encode(FORMAT))

""" Receiving the file data from the client. """
data = conn.recv(SIZE).decode(FORMAT)
print(f"[RECV] Receiving the file data.")
file.write(data)
conn.send("File data received".encode(FORMAT))

""" Closing the file. """
file.close()

""" Closing the connection from the client. """
conn.close()
print(f"[DISCONNECTED] {addr} disconnected.")

if __name__ == "__main__":
main()



EXPERIMENT 4: BER
clear
N = 10^6 % number of bits or symbols
rand('state',100); % initializing the rand() function
randn('state',200); % initializing the randn() function

% Transmitter
ip = rand(1,N)>0.5; % generating 0,1 with equal probability
s = 2*ip-1; % BPSK modulation 0 -> -1; 1 -> 1
n = 1/sqrt(2)*[randn(1,N) + j*randn(1,N)]; % white gaussian noise, 0dB variance
Eb_N0_dB = [-3:10]; % multiple Eb/N0 values

for ii = 1:length(Eb_N0_dB)
% Noise addition
y = s + 10^(-Eb_N0_dB(ii)/20)*n; % additive white gaussian noise

% receiver - hard decision decoding
ipHat = real(y)>0;

% counting the errors
nErr(ii) = size(find([ip- ipHat]),2);

end

simBer = nErr/N; % simulated ber
theoryBer = 0.5*erfc(sqrt(10.^(Eb_N0_dB/10))); % theoretical ber

% plot
close all
figure
semilogy(Eb_N0_dB,theoryBer,'b.-');
hold on
semilogy(Eb_N0_dB,simBer,'mx-');
axis([-3 10 10^-5 0.5])
grid on
legend('theory', 'simulation');
xlabel('Eb/No, dB');
ylabel('Bit Error Rate');
title('Bit error probability curve for BPSK modulation');


EXPERIMENT 1: CDMA
import numpy as np
c1=[1,1,1,1]
c2=[1,-1,1,-1]
c3=[1,1,-1,-1]
c4=[1,-1,-1,1]
rc=[]
print("Enter the data bits :")
d1=int(input("Enter D1 :"))
d2=int(input("Enter D2 :"))
d3=int(input("Enter D3 :"))
d4=int(input("Enter D4 :"))
r1=np.multiply(c1,d1)
r2=np.multiply(c2,d2)
r3=np.multiply(c3,d3)
r4=np.multiply(c4,d4)
resultant_channel=r1+r2+r3+r4;
print("Resultant Channel",resultant_channel)
Channel=int(input("Enter the station to listen for C1=1 ,C2=2, C3=3 C4=4 : "))
if Channel==1:rc=c1
elif Channel==2:rc=c2
elif Channel==3:rc=c3
elif Channel==4:rc=c4
inner_product=np.multiply(resultant_channel,rc)
print("Inner Product",inner_product)
res1=sum(inner_product)
data=res1/len(inner_product)
print("Data bit that was sent",data)


VLAB EXPERIMENT:
Download values

LCR:
No. Of multipaths 1
Reset
Repeat for 2,3 and 10
No. of channels 1
Reset
Repeat till 5
Submit
Report