Wireless networks are becoming ever more sophisticated and overcrowded,
imposing the most delay, jitter, and throughput damage to end-to-end network
flows in today's internet. We therefore argue for fine-grained mobile
endpoint-based wireless measurements to inform a precise congestion control
algorithm through a well-defined API to the mobile's wireless physical layer.
Our proposed congestion control algorithm is based on Physical-Layer Bandwidth
measurements taken at the Endpoint (PBE-CC), and captures the latest 5G New
Radio innovations that increase wireless capacity, yet create abrupt rises and
falls in available wireless capacity that the PBE-CC sender can react to
precisely and very rapidly. We implement a proof-of-concept prototype of the
PBE measurement module on software-defined radios and the PBE sender and
receiver in C. An extensive performance evaluation compares PBE-CC head to head
against the leading cellular-aware and wireless-oblivious congestion control
protocols proposed in the research community and in deployment, in mobile and
static mobile scenarios, and over busy and quiet networks. Results show 6.3%
higher average throughput than BBR, while simultaneously reducing 95th
percentile delay by 1.8x
