Why i could not upload file more than 3 mb using php at amazon ec2 server?

I am working with Amazon EC2 server with linux instance. In my project user can upload video. So i used php to upload the file. It is working in other server but not working in amazon ec2 server. When i upload file less than 1 mb it is working but if the file size is greater than 3mb than it is not working. I dont know where to set the permission to upload large file. what can i do?

This is my sample code.

 <?php
    $fileName = $_FILES["file1"]["name"]; // The file name
    $fileTmpLoc = $_FILES["file1"]["tmp_name"]; // File in the PHP tmp folder
    $fileType = $_FILES["file1"]["type"]; // The type of file it is
    $fileSize = $_FILES["file1"]["size"]; // File size in bytes
    $fileErrorMsg = $_FILES["file1"]["error"]; // 0 for false... and 1 for true
    if (!$fileTmpLoc) { // if file not chosen
        echo "ERROR: Please browse for a file before clicking the upload button.";
        exit();
    }
    if(move_uploaded_file($fileTmpLoc, "test_uploads/$fileName")){
        echo "$fileName upload is complete";
    } else {
        echo "move_uploaded_file function failed";
    }
    ?>