Error: android.os.NetworkOnMainThreadException AndroidStudio

I am trying to send two parameters to my webservice through POST and I am presented with the error android.os.NetworkOnMainThreadException , when trying to execute the line of code      String respuesta = mRequest.execute(nameValuePairs);

The code of my class is as follows.

public class ConexionWS implements MInterfarceTask {

JsonObjectRequest jsonObjectRequest;
RequestQueue request;
Context getApplicationContext;
String codigo, passw;
private  String url;

@Override
public void onPreExecute() {


}

@Override
public void doInBackground() {

    url = "http://10.20.91.61/carnet/webServiceCarnet.php";

    try {
        MRequest mRequest = new MRequest(new URL(url));
        LinkedHashMap<String, String> nameValuePairs = new LinkedHashMap<String, String>();
        nameValuePairs.put("documento", codigo);
        nameValuePairs.put("pass", passw);

        String respuesta = mRequest.execute(nameValuePairs);
        JSONObject jsonObject = new JSONObject(respuesta);


    } catch (JSONException e) {
        e.printStackTrace();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Please help me how to solve this error. or if there is another method to send data through POST more effective let me know. THANK YOU