Our objective is to fundamentally advance today’s single user, mmWave Gbps WLANs by scaling them in spectrum, user density, and robustness. We target the whole spectrum range from 60 GHz to 1 THz, which we refer to as S-T bands (Sixty GHz to Terahertz). Via a combination of PHY and link layer innovations, we will design the first S-T WLAN offering multi-Gbps and Tbps data rates, supporting both downlink and uplink multi-user multi-stream communication, and providing robust always-on connectivity. To realize this, our goals include the following integrated research thrusts.
- The first thrust will theoretically and experimentally develop new PHY layer techniques that maximize the utilization of the multi-GHz-wide channels available in S-T communication systems. In the downlink, novel bandwidth hierarchical modulations are proposed as a way to enable simultaneous transmissions from users within the same transmit antenna beam. In the uplink, novel multi-beam codebooks will be designed to increase the path diversity and enable simultaneous directional transmission from users within the same area towards a common AP.
- The second thrust will first explore the empirical limits of multi-user multi-stream communication in S-T bands. It will then design and evaluate low-overhead user and beam selection protocols for enabling downlink and uplink multi-user multi-stream communication in S-T WLANs, leveraging the hierarchical modulation schemes and multi-beam codebooks from the first thrust.
- The third thrust of the project will design the first PHY-assisted link adaptation framework to realize robust S-T WLANs. The thrust will design algorithms that leverage unique PHY layer metrics to detect client mobility, blockage, interference, and poor channel, and develop techniques for fine-grained mobility and blockage classification. The final outcome is a set of policies to determine when to trigger adaptation and select the right adaptation strategies — rate adaptation, beam steering, beam width adaptation, MU-MIMO user selection, switching to a lower frequency band — in different scenarios.