Improve speed in writeRead loop while communicating with Raspberry Pi 3 B+

I have a code to get a value from ADC(mpc3208).

It works fine, but to get stable value I use 'for' loop and calculate median after gathering 30 values.

Matlab is connected with Raspberry Pi by wifi, and I have encountered speed issue.

The loop spends too long time (>0.1s) to gather 30 ADCvalues, I want to improve its speed.

I have been trying to find any method, but I still haven’t found suitable way.

Here is my code, Anyone who knows the way to solve, please help me.

function raspberry_test_blackborad
clc; clear all; warning('off','all')

clear rpi
rpi = raspi();

mcp3208 = spidev(rpi, 'CE0');
NumSample=30;
ADCval_array=zeros(NumSample,1);
for i=1:NumSample
    data = uint16(writeRead(mcp,[bin2dec('00000110'), bin2dec('11000000'), 0])); %ch=3
    highbits = bitand(data(2), bin2dec('1111'));
    ADCval = double(bitor(bitshift(highbits, 8), data(3)));
    ADCval_array(i)=ADCval;
end
ADCval=median(ADCval_array);