This research investigates the design and engineering of mobile data services from a business model standpoint. The idea is that creating innovative mobile data services requires developing innovative business models. Indeed, innovative business models can help translate technological potential into economic value and allow telecoms to achieve their strategic objectives. This research develops an ontological framework, termed as "V4 Mobile Service BM Ontology". This Ontology incorporates four design dimensions: (1) value proposition including targeting; (2) value architecture including technological and organizational infrastructure; (3) value network dealing with aspects relating to partnerships and co-operations; and finally (4) value finance relating to costs, pricing, and revenue structures. Within these four dimensions, sixteen design concepts are identified along with their constituent elements. Relationships and interdependencies amongst the identified design constructs are established and clear semantics are produced. This research also identifies key value drivers in the mobile telecommunications industry.