Not sure about Huawei, but Samsung is not using their own modem in all of the phones they make. I'm not sure what % but they do use Qualcomm's modem in at least some of the models.

3G is based on CDMA technology (wideband CDMA) and does require licensing fees. It doesn't really matter whether the chip manufacturer or the phone maker pays the fees. The end result is that non-Qualcomm chips make the product more expensive (and Qualcomm gets stronger anyway due to licensing fees).