We present the third generation of Argos platforms, ArgosV3, intended for real-world applications and research. Developed from scratch specifically for many-antenna MU-MIMO, ArgosV3 is highly efficient in space, power, computation, and cost. While this new platform is highly configurable, featuring FPGA SoCs and frequency agile transceivers capable of operation from 50 MHz to 3.8 GHz, it is also highly compact and power efficient, enabling a complete 160 radio base station in less than 2 cubic feet. ArgosV3 is currently being deployed in a campus-wide multi-cell many-antenna network. For our demonstration we will show a single ArgosV3 base station serving multiple clients using a realtime LTE stack.

While the UHF band exhibits superior propagation characteristics compared to other frequency bands used for broadband communications, limited spectral availability in time and space necessitates high spectral efficiency techniques such as Multi-user MIMO (MU-MIMO). In this paper we design and implement the first open MU-MIMO Software-Defined Radio (SDR) platform that operates on an order of magnitude frequency range, from 300 MHz to 5.8 GHz. We perform a comprehensive set of over-the-air experiments to evaluate the potential of UHF-band MU-MIMO in comparison to 2.4 and 5.8 GHz WiFi bands encompassing a range of operating environments. We evaluate MU-MIMO performance in both outdoor, indoor, line-of-sight (LOS), and non-line-of-sight (NLOS) environments, and demonstrate that while the temporal correlation of the measured UHF environment is increased, it does not come at the cost of increased spatial correlation as measured by the Demmel condition number, thus proving highly attractive for MU-MIMO. This evaluation demonstrates the effectiveness of MU-MIMO transmission techniques in UHF bands for high spectral efficiency and low-overhead wireless access.

We present a real-time software-defined radio (SDR) platform for prototyping and measuring the performance of broadband UHF radio networks operating over long distances with point-to-multipoint (PTMP) non-line-of-sight (NLOS) networks. Enabled by the Wideband UHF Radio Card (WURC), a custom high-power and frequency-flexible radio transceiver daughter-card for FPGA-based digital basebands, the 802.11 DCF-like MAC and PHY implementation is completely open source. We demonstrate a long-range PTMP NLOS network bonding several of the white space television channels available in Maui, Hawaii. Off-the-shelf client devices can use this network via 802.11a/g links implemented with the same SDR framework. The multi-carrier channel estimates and real-time MAC statistics of connected nodes in UHF and 2.4 GHz are recorded and displayed in real-time, demonstrating an unprecedented amount of flexibility in unlicensed frequency bands, enabling real-time TV-band cognitive networks and small-cell research deployments.