Research On Multicast/Broadcast Services In Wireless Heterogeneous Networks

With a growing number of multimedia services emerging, there is a large need for wireless network resources. One efficient way to utilize the limited wireless resource is the broadcast and multicast technology which implements a point-to-multipoint transmission mode since the point-to-point transmission mode would waste plenty of bandwidth and power when the number of User Equipments who receive the same service is very large. In recent years, some wireless and mobile multicast/broadcast solutions have been proposed and standardized, such as Multimedia Broadcast or Multicast Service(MBMS) in 3GPP(Third-Generation Partnership Project). On the other hand, the evolution of mobile and wireless communication also results in a large number of wireless technologies, such as cellular network, wireless local area network and Vehicular Ad-hoc NETwork(VANET). To provide seamless and ubiquitous mobility support or to combine advantages of different wireless access technologies, interworking and vertical handover among heterogeneous networks have been raising a lot of interests in both academic and industrial worlds. Due to the rapid development of multicast/broadcast services and wireless network heterogeneity, issues related to seamless multicast/broadcast mobility support in heterogeneous networks are also of value and requirement.To support multicast/broadcast service in heterogeneous networks, we propose a solution based on the MBMS architecture and specified 3GPP enhancements for non-3GPP accesses so that we could better utilize the current network. The core idea is to introduce a framework for MBMS support in heterogeneous networks with enhanced Broadcast-Multicast Service Centre(BM-SC) serving as the anchor, direct interfaces between BM-SC and Broadcast Service Node(BSN) in CDMA2000 network for MBMS service provision and management on Trusted Non-3GPP IP Access, and direct interfaces between BM-SC and enhanced Evolved Packet Data Gateway(e PDG) which can not only receive MBMS data from and interwork with BMSC but also manage and control MBMS service on Untrusted Non-3GPP IP Access(WLAN/WiMAX Access).To manage resources for multicast/broadcast service in heterogeneous networks, we propose a solution for inter-Radio-Access-Technology(RAT) energy saving. Given that multicast service is supported on heterogeneous accesses, we formulate the choice of working cell and transmission mode for each UE in the heterogeneous wireless networks as an optimization problem by using Integer Liner Programming and then propose a distributed algorithm based on the analysis of Lagrange dual function. Through analysis and simulation, we can find out that Lagrange dual based algorithm can reduce overall power consumption efficiently.To support multicast/broadcast service in integrated VANET-cellular heterogeneous wireless networks, we demonstrate an effective and efficient solution aimed to enable MBMS provision in the VANET-cellular networks based on a two-phase cooperative transmission strategy. Moreover, our proposal combines advantages of these two heterogeneous networks and the nature of multicast/broadcast technology so that the traditional problems in VANET or cellular networks might be better solved. In addition, through performance analysis and simulation result, the two-phase transmission mode in VANET-cellular heterogeneous networks has the potential to improve the network performance and user experience.There are still many problems to be investigated for multicast/broadcast services in heterogeneous networks. In practice, there could be different requirements, so different designs for multicast/broadcast seamless support and vertival handover need to be proposed. Besides, it is worth studying other possible resource managment schemes under different models and optimization objects.