Coverage Extension of Software Defined Radio Platforms for 3GPP 4G/5G Radio Access Networks

The quick development of Software Defined Radio (SDR) platforms has simplified experimenting 3GPP cellular wireless access technologies in software. Thus, many implementations of 3GPP 4G/5G SDR Radio Access Networks (S-RANs) have been developed in the literature. However, most of these S-RANs are tested and evaluated in laboratories within very short-range cells. One of the main reasons for this restricted test environment is the limitation of the output transmit power of SDR devices. The objective of this paper is to show how the cell coverage of 3GPP 4G/5G S-RANs can be extended (numerically and experimentally) to reach a desired cell size such as micro and macro-cells. For this purpose, we first model the communication between user equipment (UE) and eNodeB/gNodeB using an SDR-based radio transceiver in both uplink and downlink directions. Then, we extract the parameters affecting the transmitted and received signal power. After, we numerically analyze the impact of each parameter on the cell coverage. Finally, to validate the numerical analysis, we conduct experiments using a testbed based on an open-source S-RAN implementation to evaluate the transmit power, receive power, Signal-to-Noise Ratio (SNR), and Block Error Rate (BLER). The obtained numerical and experimental results show that different 4G/5G cell sizes can be achieved by using appropriate external equipment including amplifiers, filters, and antennas calibrated according to the employed SDR device specification.