PHP socket_read does not return empty string ''

Hi there's problem with the socket_read function below, it does not return empty string '' after it has finished reading the data. On second call to socket_read() it just hang there, the page keep loading in browser with no return. It works if the server close the connection, is it a must for server to close the client socket ? Thanks

    $json = $_GET['json'];

    /* Get the port for the WWW service. */
    // $service_port = getservbyname('www', 'tcp');
    $service_port = "1111";

    /* Get the IP address for the target host. */
    $address = "192.168.3.5";

    /* Create a TCP/IP socket. */
    $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    if ($socket === false) {
        echo "socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
        die();
    } else {
        //echo "OK.\n";
    }

    //echo "Attempting to connect to '$address' on port '$service_port'...";
    $result = socket_connect($socket, $address, $service_port);
    if ($result === false) {
        echo "socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket)) . "\n";
        die();
    } else {
        //echo "OK.\n";
    }

    $out = '';

    //echo "Sending HTTP HEAD request...";
    $result = socket_write($socket, $json, strlen($json));

    if ($result === false) {
        echo "socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket)) . "\n";
        die();
    } else {
        //echo "OK.\n";
    }



    echo socket_read($socket, 2048);
    echo socket_read($socket, 2048);
//  
     // while (socket_read($socket, 2048) !== '') {
        // echo $out;
//       
     // }
//   
     socket_close($socket);