The mobile communication market has grown rapidly over the past 10 years, but the market may reach saturation in the foreseeable future. More flexible mobile networks able to meet various user demands and create new market openings are needed for further growth. Heterogeneous networks are more suitable than homogeneous networks for meeting a wide variety of user demands. There are two types of heterogeneous network: a closed-type whose network resources are deployed and operated by communication carriers, and an open-type whose network resources would be deployed not only by existing operators but also by companies, universities and so on. It will be easy for newcomers to enter mobile businesses in an open heterogeneous mobile network, so many innovative services are likely to be provided through cooperation between various companies or organizations. This paper proposes revised architectures for TISPAN-NGN which corresponds to heterogeneous networks and open mobile markets, and presents new business models.