I'm struggling with calculating the power on Pattern Division Multiple Access (PDMA) when transmitting on Four subcarriers

I'm simulation the Pattern Division Multiple Access (PDMA)
where K: is number of subcarriers/channels, well after the function PDMA_signal thats were the problem starts when 
i'm transmitting more than one QPSK symbol for each user k.

For example1: a working example

        [signals,HS] = PDMA_signal(modulatedSymbols,PDMA_patterns,channel_gain);

signals =

-2.4742 + 2.4742i
 0.3640 + 0.8079i
 1.7584 - 1.7584i
 2.5434 + 1.6466i

        signal_power = sum(abs(signals).^2)/K;
 signal_power =

    7.0981

        noise_power = signal_power/snr;
noise_power =

    7.0981
        sigma = sqrt(noise_power);
sigma =

    2.6642
        noise = sigma *(randn(K,size(signals,2))+1i*randn(K,size(signals,2)))/sqrt(2);
noise =

   1.3682 + 0.0104i
   0.6090 - 0.7717i
   4.2299 - 1.5291i
  -0.0663 - 0.3606i        
       y = signals + noise;

y =

-1.1060 + 2.4845i
 0.9730 + 0.0363i
 5.9883 - 3.2875i
 2.4771 + 1.2860i

For example2: example where i need help

[signals,HS] = PDMA_signal(modulatedSymbols,PDMA_patterns,channel_gain);

signals =

   0.1947 - 0.1947i  -2.2074 + 3.2085i
   0.9024 - 0.9024i   2.3989 - 0.2145i
   0.7649 - 0.7649i  -1.2776 + 2.9950i
  -2.5269 + 2.5269i  -1.6450 + 1.6450i

        signal_power = sum(abs(signals).^2)/K;

signal_power =

    3.9113    9.2456

        noise_power = signal_power/snr;
noise_power =

    3.9113    9.2456
        sigma = sqrt(noise_power);
sigma =

    1.9777    3.0407
        noise = sigma *(randn(K,size(signals,2))+1i*randn(K,size(signals,2)))/sqrt(2);
noise =

?

       y = signals + noise;

y =

?

My problem is calculating the signal of more than two symbols together not separate?

[Monika Singh]

Hi Samson Zitha,

I am also working on PDMA. I need some of your guidance.

Hope for getting some reply.