Leti Demonstrates New Multicarrier BF-OFDM Waveform for Rural and Maritime Broadband Radio

Leti and Scottish SME specializing in TVWS (TV White Space), CloudNet IT Solutions, have declared joint field trial results for a new flexible multicarrier system in the Orkney Islands designed to demonstrate a new post-OFDM (orthogonal frequency-division multiplexing) multicarrier waveform.

The trial showed that the post-OFDM multicarrier waveform, a block filtered-OFDM (BF-OFDM), can overcome all shortcomings inherent in actual OFDM waveforms (WiFi/LTE) and is backward compatible with existing receivers.

Back in January 2017, Leti had received an 18-month license from Arcep, France's telecommunications regulatory agency, to run a field trial with multiservice transmission using the 3.5 GHz TDD band. They are continuing to deploy their patented multicarrier technology on broadband wireless channels. In the Orkney Islands field trial, Leti demonstrated the flexibility as well as the performance of the technology in terms of spectral efficiency in the 700 MHz TVWS band for rural broadband and maritime broadband radio scenarios. The measurements were supported under the framework of the Horizon2020 EU-funded GateOne project.

Leti's post-OFDM multicarrier waveform is designed to achieve good frequency localization and support simultaneous single-carrier and multicarrier modulations, along with classical multi-antenna systems, e.g. multiple-input/multiple-output (MIMO) solutions. The duration of the elementary communication slot is configurable and can be adapted to the targeted latency and channel conditions. In addition, classical multi-user (MU) access can be used on top of it, and even combined with MIMO, leading to MU-MIMO technologies in fragmented spectrum scenarios.

The Orkney Islands deployment assessed performance of a broadband transmission in a 16 MHz fragmented spectrum channel, while fitting with ETSI EN 301 598 TVWS regulation. The measurements performed at the beginning of November strongly validated the trial's innovative concepts in a real-life situation. Rural broadband content delivery was demonstrated up to 20km, using non-contiguous channels. Leti's over-the-air versatile and portable test platform based on field-programmable gate arrays (FPGA), ARM processors and agile RF front-end was used to demonstrate a broadband transmission. The same set of equipment is also part of the 5G Leti testbed under evaluation in the future 5G 3.5 GHz band.