Mobile Communication Team#3

• Boburjon Iskandarov
• Oybek Amonov
• Rakhmatjon Khasanov
• Sardorbek Allaberganov
• Bokhodir Urinboev

Needed Wrappers

• OpenCV
• Numpy
• Matplotlib

Signal conditioning

Opencv for loading

pix = cv2.imread(file)
height, width, channels = pix.shape
demod_img = np.zeros((height, width, channels))

RGB to binary

for i in range(height):
	for j in range(width):
        rgb=pix[i][j]
        binString=''
        for k in np.arange(3):
            binary = bin(rgb[k])[2:].zfill(8)
            binString += binary
        signal = np.array(bpsk(binString)).flatten()				

Digital to Analog Modulation

def bpsk(binString):
    amplitude = []
    for i in range(len(binString)):
        if binString[i] == '1':
            amplitude.append(np.sin(time))
        else :
            amplitude.append(-np.sin(time))
    return amplitude

Simulating Noise

def awgn(signal, regsnr):
    noise = np.random.randn(len(signal))
    noise_var = 0.5*10**(-regsnr/10)
    Chan_Noise = noise * np.sqrt(noise_var)
    return Chan_Noise

Demodulation

carr = np.sin(time)
def bpsk_demod(signal, L):
    d = ''
    for i in range(0, len(signal), L):
        sum = np.sum([signal[i+j]*carr[j] for j in range(L)])
        if sum >= 0:
            d += '1'
        else:
            d += '0'
    return d

Detection

def NEB(binString, demodBinString):
	return sum(1 for a, b in zip(binString, demodBinString)\
               if a != b) + abs(len(binString) - len(demodBinString))

Bit Error rate(BER)

BER = []
for i in range(-10,11,5):
    %matplotlib inline
    BER.append(simulate(i, file))
%matplotlib inline
plt.figure()
plt.grid()
plt.plot(range(-10,11,5), BER)
plt.show()

Reconstructe Image

    demod_img[i][j] = [int(demodBinString[0:8],2), int(demodBinString[8:16],2), int(demodBinString[16:24],2)]
    BER += NEB(binString,demodBinString)
cv2.imwrite('photo_'+str(SNR)+'.jpg', demod_img)

SNR = -15

Before	After

SNR = -10

Before	After

SNR = -5

Before	After

SNR = 0

Before	After

SNR = 5

Before	After

SNR = 10

Before	After