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A Spanish group has designed and implemented algorithms for the improvement of the performance of MIMO-OFDM systems. This technology is capable of providing high data rate wireless communications. The developed algorithms allow, on one side, the correction of the imperfections introduced by radio-frequency equipment and, on the other side, adaptation of the transmission to the channel characteristics. The group is looking for technical cooperation.
MIMO-OFDM technology Multiple Input Multiple Output
–Orthogonal Frequency Division Multiplexing) combines the diversity and capacity of MIMO with the
immunity to multipath of OFDM, resulting the ideal candidate for the provision of high speed
wireless communications in harsh environments.
A Spanish group has developed and implemented
algorithms that optimize the use of this technology: on one hand, by correcting undesired effects
introduced by radio-frequency systems, such as phase noise; on the other hand, adapting the
transmitted signal to the channel, leading to a much higher spectral efficiency.
Phase noise, due to
the non-ideality of oscillators, exists in every transmitting or receiving equipment, It is
particularly damaging for OFDM systems due to the fact that it produces a loss of orthogonality
between the subcarriers, one of the key features for the right functioning of this technology.
The
developed algorithms allow estimating and correcting this phase noise, thus avoiding its dangerous
effects on the received signal.
Adaptive modulation is a technique that allows taking advantage of
the capabilities of a transmission channel, choosing the modulation that permits the transmission of
the highest amount of information, according to the channel state. In turn, knowledge of the channel
in the transmitter is mandatory, and that is not always possible. For that reason, the group has
developed algorithms to adapt the MIMO-OFDM signal to the channel when the latter is not perfectly
and instantaneously known, but only its statistics, and also procedures to convey the channel state
information from the receiver (where it is usuaily estimated) to the transmitter.
The prototype
that has been implemented allows to verify the behavior of these algorithms in realistic
situations.
Innovative Aspects:
The main difference between these algorithms and other existing
ones is the degree of required channel knowledge. Many algorithms assume that the channel has been
previously and ideally estimated. This is not possible in real systems, so these algorithms either
correct jointly channel and phase noise effects or adapt the signal to the channel without its
perfect previous knowledge.
Domain of
Application
This technology provides high speed wireless
transmission so that it causes a cost reduction and/or improvement of the performance offered by
mobile communications operators.
Stage of
Development
Development phase - Laboratory tested
Exploitation of RTD Results
National Programmes
IPR
Others
No patent application has been presented. The
algorithms are described in some publications.
Company
Details
Collaboration Type
- Adaptation to specific needs
- Joint further development
- Type of partner sought: industry
- Specific area of activity of the partner: manufacturers or operators of mobile communications
- Task to be performed by the partner sought:Manufacturers may improve their equipment; operators may verify the performance that can be achieved with this kind of technology through a prototype.
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