xG-SS: Towards a Hardware and Simulation Experimentation Platform for Spectrum Sharing with 5G NR-U

The advent of 6th Generation (6G) wireless systems and the increasing demand for spectrum to accommodate a growing number of users and diverse services have necessitated novel ap- proaches to spectrum sharing. Among these approaches, distributed spectrum sharing offers the most flexibility by allowing real-time spectrum use based on user demand and network con- straints. However, this approach presents significant challenges due to the probabilistic nature of system dynamics and the autonomous behavior of each incumbent, which require advanced strategies to predict and manage spectrum usage effectively. Listen-Before-Talk (LBT) is the most widely adopted method for distributed spectrum sharing in unlicensed bands. While LBT has been extensively studied in the context of Wireless Fidelity (Wi-Fi), providing key insights into its performance under various conditions, its application in synchronized, slot-scheduled sys- tems like New Radio (NR) Unlicensed (NR-U) remains underexplored. This gap exists primarily due to the lack of hardware testbeds and system-level simulation platforms that are essential for evaluating the effectiveness of LBT in NR-U and for developing improved methods for operating in shared spectrums with deterministic worst-case delays. This thesis addresses the existing gap by proposing a reference architecture for spectrum sharing based on 5th Generation (5G) NR-U to facilitate further research and experimentation in distributed spectrum sharing. The approach taken in this thesis is threefold: (i) the establishment of a system architecture for an end-to-end 5G NR-U system based on existing work in hardware and simulation models; (ii) the realization of this system model on the Network Simulator 3 (ns-3) discrete-event simulator by leveraging developments from the 5G Long-Term Evolution (LTE) Enhanced Packet Core (EPC) Network Simulator (LENA) (5G-LENA) system architecture; and (iii) the conceptual design for implement- ing the Physical (PHY) layer of a 5G NR-U system using Software-Defined Radios (SDRs) and the OpenAirInterface (OAI) 5G software platform. A key novelty of this reference architecture is the proposed mitigation of LBT latency in split architectures with SDRs and General-Purpose Processors (GPPs). The LBT block is designed for implementation within the Field Program- ming Gate Array (FPGA) of Universal Software Radio Peripheral (USRP) SDRs, thereby enabling heterogeneous coexistence experimentation with Common Off-the-Shelf (COTS) Wi-Fi Access Points (APs). The thesis presents a simulation-based experiment that optimizes traffic manage- ment to improve the ability to serve delay-critical traffic in NR-U systems operating under ho- mogeneous coexistence conditions. The thesis then outlines a reference design for exploring heterogeneous coexistence between Wi-Fi and NR-U in the sub-7 GHz spectrum. This concep- tual framework leverages a proposed hardware experimentation platform with SDRs. The in- frastructure supporting these simulations and proposed hardware experiments is envisioned as virtualized resources over the Commonwealth Cyber Initiative (CCI) xG Testbed, with potential extensions for advanced spectrum sharing use cases across indoor and outdoor testbed sites. The thesis outlines potential enhancements to this testbed, specifically toward spectrum sharing with scheduled-access systems.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Computer Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2025

Author dc:creator

• Sathish, Aditya

Chairs dc:contributor.committeechair

• Pereira da Silva, Luiz Antonio
• Da Silva, Aloizio

Committee members dc:contributor.committeemember

• Gosh, Monisha
• Tripathi, Nishithkumar Dhananjay

• Testbed
• Experimentation
• Spectrum Sharing
• Unlicensed Spectrum
• 5G
• NR-U
• Channel Access Priority Classes
• ns-3
• 5G-LENA
• Software-Defined Radios
• USRP
• RFNoC

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:41564

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/124579