I-Lab: Media networking
The telecommunications world today features a variety of heterogeneous access network technologies, be it wired, fixed wireless, or mobile and various other networks, such as satellite and terrestrial broadcast networks.
User communication devices with multiple network connection methods, such as Ethernet, WiFi, Bluetooth, and cellular mobile have become widely available.
Media networking over such IP wireline and wireless networks can be either unidirectional from a sender to one or more receivers, such as video streaming, or bidirectional or interactive multidirectional between two or more communicating parties, such as audio/video conferencing.
The support of services that are based on high-quality, bandwidth-intensive, and delay-sensitive multimedia applications is coupled with many challenges. For example, the delivery of 3D video services to individual users poses more challenges than conventional 2D video services, due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context (e.g. preferences, location).
The media compression technologies introduce coding distortions while the networks introduce loss and/or latency of the transmitted information due to network variability and lack of service guarantees with respect to available bandwidth, latency, and jitter, especially in wireless networks, resulting in distortions in the decoded signal due to packet loss and/or packets being delivered after they are required.
The main objectives of this research theme are as follows:
- To achieve increased overall communication and energy efficiency, enhanced load control, and service coverage, utilising the heterogeneous access technologies and network configurations that will exist in the environment
- To support a multiplicity of user preferences and of applications with various traffic demands and QoS requirements
- To overcome the last-mile performance bottlenecks, enabling the delivery of rich media content applications that require real-time capabilities and high speed accesses, setting high requirements on the network
- Support anytime, anywhere connectivity with high performance applications, combine heterogeneous access technologies (3GPP LTE, WiMAX, WLAN, etc.)
- Addresses the problems related with the transmission of high-quality, bandwidth intensive, and delay sensitive media content across heterogeneous networks (e.g., different available data rates, QoS discrepancies, time-varying transmission characteristics of the wireless channel)
- Multi-RAT technologies for increased throughput, reliability, coverage, and functionality
Figure 1: Media networking over heterogeneous access networks
- Investigating efficient transmission techniques for 3D video delivery over mobile broadband networks, such as 3GPP LTE and WiMAX
- The effective exploitation of importance and redundancies in 3D video data representation formats/coding approaches for improving the system’s performance in terms of the efficient utilisation of the available radio resources
- Scalability concepts for handling 3D video communications with heterogeneous terminals in the network
- Error robustness and resilience techniques for ensuring high-quality 3D video transmission
Figure 2: Scalable and resource efficient 3D video delivery over WiMAX networks
- Take advantage of already deployed network infrastructure for the delivery of multimedia content (e.g., mobile TV, mobile 3DTV) to large-scale user communities
- WiMAX MBS and 3GPP LTE E-MBMS provide an efficient transmission method in the downlink direction for the concurrent transport of data common to a group of end-users through a shared radio resource
- Mapping of multi-layered 3DTV video bit stream to WiMAX/LTE transmission modes for scalable, resource efficient, and error robust 3D video multicast/broadcast services
Figure 3: WiMAX MBS with multi-layered 3D video transmissions
Figure 4: 3GPP LTE E-MBMS
- Making the media layer information available in lower network layers based on cross-layer information forwarding techniques (e.g., using the IP header’s DSCP field) for indicating the packets’ importance
- Quality-driven cross-layer design is more important in wireless access networks, since the end-users have different reception capabilities (e.g., propagation conditions, device capabilities) and the available radio resources in wireless networks are scarce and time-varying due to, for example, interference and user mobility
- Investigating the interaction and cooperation between the upper layers (e.g., video coding) and the transmission characteristics of wireline and wireless networks, including the utilised transmission protocols and data link and physical layer functionalities for optimising the received media quality per user
Figure 5: Cross-layer design for multi-layered 3D video delivery
Figure 6: Cross-layer design KPIs
- Offline transmission system simulators are not very adequate for investigating real-time multimedia applications behaviour (e.g., end-to-end QoS, end-user perception)
- Allows for real-time configuration/tuning of system parameter settings at different layers (e.g. modulation type, FEC code type, channel coding rate, SNR, etc.)
- Utilised for testing different IP-based multimedia applications (e.g., 2D/3D video streaming)
- Allows for assessing the performance of algorithms, protocols, and services
Figure 7: Architecture/protocol stack for 3D video over WiMAX BS/SS test-bed
Figure 8: Radio interface protocol stack GUI for control, monitoring, and measurements
Figure 9: 3D video over WLAN AP/client test-bed