IP multimedia subsystem standardized by 3GPP has attracted the endorsement of other network technology providers. IMS is the most complete IP-based service control and management overlay (using SIP) that sets up an overlay on the under-laying transport infrastructure and provides the possibility of end to end IP based services. Adopting IMS as the service control overlay in different technologies like WLAN, xDSL and cable allows their operators to share their infrastructure with 3G wireless networks not only in transport level but also in service level. This convergence which is called horizontal convergence is sought in NGN-next generation network architecture. Provisioning end-to-end QoS in such heterogeneous paradigms is a challenging task according to the different strategies of resource reservation over different technologies. In this paper we have defined new architecture to resolve some of the existing problems existing in IMS policy based QoS control model that don't let end-to-end QoS control between different technologies and domains.