MIMO Hardware Demonstrator
Principal Investigator:
Prof. Björn Ottersten
Funding source(s):
European Space Agency
Researcher(s):
Dr. Bhavani Shankar, Dr. Symeon Chatzinotas
Future air interfaces provide significantly higher capacity, bit rates and flexibility compared to existing systems. The performance improvement is based on new methods such as multicarrier techniques, use of multiple transmit and receive antennas (MIMO) and more efficient utilization of the radio channel capacity. The capacity gain that can be reached with the help of MIMO techniques is particularly promising and importance for hybrid terrestrial/satellite mobile systems.
As stated in the invitation to tender by ESA, satellite networks, with the wide coverage they can offer, have the potential to maintain a strong presence in the wireless market, especially considering the broadcast to mobile market segment. In this regards, the introduction of MIMO techniques and their possible adaptation to the satellite media, is seen as an important step in order to improve the offered services, in term of data rates and availability. Such a step may prove to be necessary in order to keep satellite operators competitive with terrestrial ones.
Various techniques to utilize multiple antennas have been proposed and also taken into practice. Diversity gain can be achieved by combining received signal from multiple antennas if the correlation between the radio channels seen by those antennas is low enough. It is also possible to utilize transmit diversity for example by utilizing space-time-coding on the transmitted signal, where information is distributed on both time and spatial (antennas) dimensions and coded allowing the receiver to detect and separate these signals. In addition to diversity gain, MIMO can be utilized to enhance link throughput, which has enabled a major step towards bit rates required by futures broadband communications systems such as IMT-A (4G), where for mobile users bit rates of 100Mbps and for hot-spots bit rates of 1Gbps are targeted.
