A lightweight communication protocol reduces overhead for small data transmissions from a wireless device to a base station over an uplink channel. The wireless device is preconfigured with a device identifier that is known to the base station. The preconfigured device identifier is associated with a static tunnel between the base station and a serving gateway. The wireless device transmits application data to the base station in a medium access control packet without using higher layer protocols. When the base station receives the medium access control packet, it maps the application data to the tunnel associated with the preconfigured device identifier.