I'm trying to install CiviSMS on a Drupal based CiviCRM install. I have Drupal 7.43 running CiviCRM 4.7.8 on a CentOS 7 platform.
Did you have a look at the extensions directory on:
https://civicrm.org/extensions filter for SMS Select one and you'll find the download link
Note that both Clickatell and Twilio don't have a 4.7.x stable version listed yet - best to contact their authors to see where things are at.