The support of broadcasting and multicasting as an efficient L3-based service poses rigorous requirements to the next generation mobile communication architectures. When IP multicasting has been seriously considered in mobile systems, soon has emerged the proposal of Multimedia Broadcast Multicast Service (MBMS) for 3G networks and beyond. However, with the spreading of versatile heterogeneous wireless systems, like the cooperation of European 3G (UMTS) and Wireless Local Area Network (WLAN), the problem of wireless IP datacasting arises in more complicated ways. In order to extend MBMS for UMTS/WLAN heterogeneous architectures we approach a novel framework along with a suitable and efficient WLAN MAC (Media Access Control) extension. In this work we also evaluate the performance of our proposal using a discrete event simulation environment called OMNeT++.
As the preliminary of our work, we will briefly overview the general background of UMTS and WLAN systems together with their multicasting/broadcasting capabilities and extensions, followed by the basics of the UMTS/WLAN interworking architectures.
Key Terms in this Chapter
Multimedia Broadcast/Multicast Service: a broadcasting service that can be offered via existing GSM and UMTS cellular networks, in which an uplink channel is used for interaction between the service and the user.
Service Provisioning: A set of network processes that are indispensable for proper operation of a given service.
WLAN: Wireless local area network, which is the linking of two or more computers using spread-spectrum or OFDM modulation technology based on radio waves to enable communication between devices in a limited area.
Multicasting/Broadcasting: Delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once, creating copies only when the links to the destinations split (broadcasting means delivery for all available destinations within a given subnet).
UMTS: Universal Mobile Telecommunications System, European 3GPP standardized third-generation cell phone technology, which uses W-CDMA as the underlying air interface.
Heterogeneous Communication Systems: In our context wireless networks using different access technologies, for example, a wireless network which provides a service through a wireless LAN and is able to maintain the services when switching to a cellular network is called a wireless heterogeneous network.
MAC Layered Multicast: A type of multicasting methods based on medium access control level protocols.
WLAN MAC Layer: A part of the data link layer (layer 2, specified in the seven-layer OSI model) in a wireless local area network, which provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multipoint network.
3G Context Management: A method in third-generation telecommunication system that ensures utilization of applications in different subscriber environment.