The next-generation heterogeneous networks aim to offer ubiquitous high quality IP-based multimedia services to the users anywhere at any time. The different radio networks such as Long Term Evolution (LTE), Universal Mobile Telecommunication Systems (UMTSs), Ultra Mobile Broadband (UMB), Worldwide interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), etc. are co-located in the same geographical area to provide different services are called overlay networks. The advantages of integration of these networks include increased efficient utilization of overall network bandwidth; enhanced QoS of the users and the increased support for the mobility.