Scaling Phased Array Receivers to Massive MIMO and Wide Bandwidth with Analog Baseband Beamforming

Massive multi-user MIMO is a promising technique to increase capacity with spatial filtering for spectrum reuse, and increasing SNR through array gain. There are many advantages to increasing antenna and user count in these arrays, but there is also much debate on how best to do so efficiently. An especially important decision is where to place the beamformer in the signal chain. This work proposes a hardware informed model for comparison between analog and digital beamforming, breaking down the decision into intuitive designer chosen specifications and comparing in power. The model finds that analog baseband beamforming is critical for scaling to wide-bandwidth and large arrays, especially in the presence of interferers. The hardware assumptions in the model are tested in a 16x16 beamforming receiver array in 28nm silicon. Design techniques such as noise or bandwidth limited design, two stage beamforming, and offset correction are used in the circuit implementation. The ASIC was packaged and used in a real time demonstration which performs multi-user and multi-panel operation

A Video Game-Integrated Electromyography Biofeedback Device for Use in Physical Therapy

We present a novel system to be used in the rehabilitation of patients with forearm injuries. The system uses surface electromyography (sEMG) recordings from a wireless sleeve to control video games designed to provide engaging biofeedback to the user. An integrated hardware/software system uses a neural net to classify the signals from a user’s muscles as they perform one of a number of common forearm physical therapy exercises. These classifications are used as input for a suite of video games that have been custom-designed to hold the patient’s attention and decrease the risk of noncompliance with the physical therapy regimen necessary to regain full function in the injured limb. The data is transmitted wirelessly from the on-sleeve board to a laptop computer using a custom-designed signal-processing algorithm that filters and compresses the data prior to transmission. We believe that this system has the potential to significantly improve the patient experience and efficacy of physical therapy using biofeedback that leverages the compelling nature of video games