Licas (lightweight (Internet-based) communication for autonomic services) is an open source framework for building service-based networks, similar to what you would do on a Cloud or SOA platform. The framework comes with all of the required features for building and running services on the framework, including security features.
Licas Mobile demonstrates the potential of using licas for your mobile environment. You also need to download and run the free All-in-One GUI from the 'Distributed Computing Systems' site, so you need to familiarise yourself with the desktop version first. The mobile app provides some free services to interact with your home server. It still requires you to run a server on your phone and then connect to your remote server as well, but the operation is automatic and so the app behaves like a client-server application.
The free version offers functionality to connect to your remote server, search and download files, and also perform remote web service invocations. The paid version can also provide other services. The File Service on your home server should set its root directory to the server 'web' folder of the installation. The rest is very easy.