Results and future works

Main project results

At the beginning of the project, there were a lot of theoretical analysis concerning massive MIMO for mmWave. The larger the number of transmit antennas, the greater the multiple antenna gain and the spatial multi-user multiplexing gains especially when carrying out spatial division multiplexing  access (SDMA) through digital precoding also denoted as digital beamforming. Most of the theoretical studies therefore assumed as many RF chains as the number of antennas.

On the one hand, the increase in frequency, which has since been confirmed by the allocation of new bands in mmWave for 5G, was intended to make  possible  the use of much wider bands than the previous ones (up to 2 GHz). On the other hand, the miniaturization of antennas at these frequencies was supposed to allow a considerable increase in the number of antennas or radiating elements for MIMO systems.

Nevertheless, the increase in the number of antennas envisaged  for massive-MIMO systems and the rise in mmWave  with its corollary of antennas of very small size, pose many problems of RF integration (compact circuits, consumption, OL synchronization faults, loss compensation …) we dealt with in  the M5HESTIA project.

As described in the initial proposal, the 2 projets were carried out in parallel. b<>com M5 focused on the techniques of beamsteering in very large bandwidth in FDD mode whilst M5HESTIA  focused on TDD modes. List of publications do not include b<>com results.The b<>com plateform integrated antennas developped in the framework of M5HESTIA .

In M5HESTIA, we studied new solutions based on hybrid systems requiring less RF chains than the number of radiating elements and optimized then to reach low complexity systems. We designed new antennas and RF architectures allowing very high gains as required for channel sounding in massive MIMO and new antennas for digital beamsteering integrated in the IRT b<>com platform. First measurements in both azimuth and elevation  will begin very soon and additional measurement campaigns are planned in the framework of the CominLabs mmWSounder project. Channel modelling for mobility scenario including tracking has been proposed.

How the results obtained by M5HESTIA are positioned in relation to the results of the literature is detailed in  the part dedicated to the today’s state of the art.

The results have been published in 1 accepted journal paper and 11 conference papers. 3 other journal papers have been yet submitted and are under review. Moreover, a session in a workshop commonly organized by M5HESTIA members and Orange, will held on the 8th November 2019 to promote M5HESTIA results.

Future work

This work will be directly exploited in the project mmWSounder in the framework of “Action –Innovation” of Cominlabs where the objective is to integrate the developped antenna module in a full and dynamic channel sounder based on Software Defined Radio equipment. All partners will be involved in this project to integrate antennas provided by M5HESTIA into a dynamic channel sounder, to carry out  additionnal channel measurements, to go on improving channel modelling and check theoretical simulation results with “measured channels”.

Future works could also include an  easy extension  to other mmWave bandwidths (as 28GHz). Mobility scenarios could easily be studied thanks to the proposed model. New hybrid systems antenna should be developped.

Main important results per Workpackage

WP2: Antenna design and RF architecture
  • Developping a modular approach for lens-based antennas
  • Easy duplication for other antennas (sounding and transmission) and other frequencies
  • Characterization of the first basic source antenna in accordance with electromagnetic simulations
    not always obvious in mmWave!
  • Providing a 60-MHz M-MIMO channel sounding antenna for use by Orange for measurements
  • Results in accordance with 802.11 ad norms (beamsteering) and 802.11 ay standardization standards (multi-user multibeams)
WP3: Propagation Channel Modeling
  • Analysis of  external measurement campaigns carried out by the team of Katsuyuki Haneda from the University of Aalto whose the multi-band channel sounder is based on exploiting a rotative horn antenna
  • Novel theoretical contributions on the problem of location and tracking in 5G systems
  • —Future measurement campaigns (indoor and outdoor) with antennas developed in the project
WP4: Baseband signal processing
  • Theoretical performance analysis of large-scale MIMO systems taking into account spatially clustered and ray-based channel representations according to the recognized typology of mmWave channels, namely from WP3 studies.
  • Proposal of various efficient and low complexity beamforming strategies and resource allocation algorithms well suited to mmWave propagation scenarios
  • Investigations on the potential of combining mmWave massive MIMO with spatial modulation concepts, in particular considering hybrid beamforming
WP5: Baseband implementation & Platform Integration
  • Beamsteering SU-MIMO high throughput demonstrator
  • Real time video services transmission with WP2 antenna
  • Validation of the analog and digital parts of the powerful b<>com platform
  • Agnostic platform that can be used to test new digital enablers in real environments

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