Comprehensive Experimental Evaluation of SDR-Based C-RAN 5G-SA Networks: Coverage, Throughput, and Hardware Impact
Abstract
Fifth-generation (5G) networks enable ultra-reliable low-latency communications, high throughput, and massive access, motivating deployments based on software-defined radio (SDR) and open-source stacks. This study implements and evaluates a 5G standalone (5G-SA) network using srsRAN and Open5GS, integrating universal software radio peripheral (USRP) X310/N310 radios in single-input single-output (SISO) and multiple-input multiple-output (MIMO) configurations, with 10/15/20 MHz bandwidths and a 21.76 km dense wavelength division multiplexing (DWDM) fronthaul. Results show N310 outperforms X310 outdoors, sustaining downlink (DL) throughput above 30 Mbps and uplink (UL) throughput above 15 Mbps beyond 150 m, with coverage up to 250 m under line-of-sight (LoS). In laboratory tests, N310 achieved 95 Mbps (SISO), 190 Mbps ( $2\times 2$ MIMO), and peaks above 230 Mbps under optimized $4\times 4$ configurations. However, outdoor $4\times 4$ yielded no gains because the rank indicator remained limited and MCS decreased despite comparable CQI under low multipath diversity. UL remained constrained by user equipment (UE) transmit power and the absence of UL spatial multiplexing. Under multi-UE load, UL remained stable (below 6% deviation), whereas DL decreased by up to 31%, indicating scheduler limitations. The DWDM fronthaul caused no degradation. Additionally, a user datagram protocol (UDP)-based evaluation complemented the transmission control protocol (TCP)-based analysis to isolate transport-layer effects, enabling cross-layer assessment using jitter, packet loss, UL block error rate (BLER), and hybrid automatic repeat request (HARQ) metrics, along with a TCP vs. UDP comparison. Results show that DL performance is primarily constrained by channel conditions, whereas UL is more sensitive to transport-layer dynamics. This work provides a reproducible methodology and practical insights for SDR-based 5G-SA deployments.