You are correct in saying that CDMA and W-CDMA are different/incompatible. UMTS isn't exactly W-CDMA and HSDPA, though. UMTS uses W-CDMA air-interface and often the terms are used interchangeably. HSDPA is a data solution that improves on W-CDMA, similar to how EDGE improves on GPRS for GSM networks. UMTS, W-CDMA, and HSDPA are all inter-elated but the terms do no replace each other; they refer to different aspects of a combined 3G solution.