Leti to test potential successor to OFDM

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French research institute CEA-Leti says it has developed a multicarrier waveform that could be a successor to OFDM and is planning to demonstrate the approach on the Minatec campus in Grenoble.

According to Leti, block filtered OFDM (BF-OFDM) can overcome all shortcomings inherent in LTE waveforms, including out-of-band emissions and weakness when exposed to asynchronous communications. Designed for good frequency localisation and with support for simultaneous single-carrier and multicarrier modulations, BF-OFDM supports MIMO solutions and is backward compatible with existing LTE receivers

“4G networks are quickly reaching their limits in capacity and capabilities to address new classes of services, such as massive machine-type connectivity and ultra-low-latency and ultra-reliable communications,” said Dimitri Ktenas, Leti wireless lab manager.

Leti was recently granted a six-month license by the French telecommunications regulatory agency to run a field trial with multiservice transmission in the 3.5GHz TDD band using a 40MHz bandwidth.

The over-the-air test platform will be used to demonstrate 5G multiservice transmission, with a mix of mobile broadband, cellular IoT and low latency transmissions. It will also support multi user access for investigating enhanced dynamic spectrum access and in-band full duplex (IBFD) transmission.

IBFD allows data to be transmitted and received in the same frequency band at the same time, theoretically doubling the data rate. However, practical implementations show this technique does not produce the expected improvements due to self-interference. Leti says its solution applies three approaches to mitigate this – antenna isolation, RF cancellation circuits and non linear digital filtering.