1. Introduction
The transition from 5G to 6G introduces significant technological advancements that fundamentally alter the reliability of Cell Site Analysis (CSA) and Radio Frequency Propagation Surveys (RFPS) in forensic investigations. Traditional forensic methodologies rely on static cell coverage assumptions, but 6G can incorporate Reconfigurable Intelligent Surfaces (RIS), beamfocusing, hybrid radio-optical links, adaptive wireless coverage, and real-time propagation optimization—all of which might disrupt conventional CSA techniques.
This article explores some possible key forensic challenges posed by 6G and proposes methodological adaptations to suggest the need to ensure an accurate approach to forensic investigations in *future wireless networks (*not active yet outside of the work performed inside the research arena).
2. Key 6G Technologies Impacting Forensic CSA
(A) Reconfigurable Intelligent Surfaces (RIS)
- How It Works: RIS dynamically manipulates electromagnetic waves to alter signal propagation, effectively "steering" radio signals in a controlled manner.
- Forensic Challenge: Traditional RFPS assumes static propagation models, but RIS can change coverage patterns in real time. Historical RF conditions may not be repeatable, rendering post-incident RF surveys unreliable.
- Adaptation Strategy: Forensic CSA must incorporate network logs from RIS controllers to reconstruct real-time signal pathways at the time of an incident.
(B) Beamfocusing and Near-Field/Far-Field Challenges
- How It Works: Unlike traditional beamforming, 6G focuses signals at a specific spatial point, requiring recalculations when users move.
- Forensic Challenge: The same beam may serve different locations at different times, making distance-based CSA unreliable. Call Detail Records (CDRs) cannot account for dynamic beam shifts, increasing uncertainty in forensic conclusions.
- Adaptation Strategy: Investigators must use beam-specific connection logs and network-side timing data to accurately map user-device interactions.
(C) Hybrid Radio-FSO (Free Space Optics) Transmission
- How It Works: 6G integrates optical wireless (FSO) and RF links, allowing networks to switch between them based on environmental factors.
- Forensic Challenge: Devices may become undetectable in RF-based forensic analyses if they transition to FSO links. Environmental factors (e.g., fog, rain) affect link selection, complicating forensic reconstructions.
- Adaptation Strategy: Investigators should obtain network-side transmission logs to track whether a device was communicating via RF or optical signals.
(D) Adaptive Wireless Coverage
- How It Works: 6G networks dynamically adjust cell coverage areas based on demand, user density, and time-of-day.
- Forensic Challenge: CSA methodologies assume static cell coverage zones, but 6G’s adaptive coverage challenges this assumption. A forensic RF survey conducted after an event may not reflect the coverage area at the time of the incident.
- Adaptation Strategy: Forensic analysts must use historical network management logs to verify coverage area configurations at the relevant time.
(E) Real-Time Propagation Optimization
- How It Works: AI-driven optimizations in 6G continuously modify network conditions to maximize efficiency and user experience.
- Forensic Challenge: Traditional RFPS methodologies rely on static RF environment assumptions, which 6G invalidates through real-time adjustments. Forensic conclusions based on past RFPS data may no longer be admissible in court.
- Adaptation Strategy: Investigators must shift from post-incident RF surveys to real-time network condition logging at the time of an event.
3. Recommendations for Future 6G Forensic CSA
(A) Move Beyond CDR-Based CSA
- CDRs are insufficient for 6G investigations due to: Beam-level user targeting, RIS-based reflections, and adaptive network changes. The inability of CDRs to track FSO-based communications.
- Alternative Data Sources: 6G Core Network Logs: Provide beam-level user connectivity data. Timing Advance and Angle of Arrival (AoA) Logs: Help estimate precise device positioning. AI-Driven Forensic Network Models: Can reconstruct historical network conditions.
(B) AI and Machine Learning for RF Reconstruction
- AI-based forensic models can: Simulate past network behaviours based on archived data. Predict how adaptive wireless coverage changed over time. Factor in RIS reflections and hybrid RF-FSO transitions.
- This enables forensic investigators to estimate historical RF conditions more accurately.
(C) Legal and Courtroom Considerations
- Defence may challenge 6G CSA evidence by arguing: "Did your forensic analysis account for RIS and adaptive coverage?" "Can you prove the network conditions were identical at the time of the event?" "How do you verify a device’s location given beamfocusing dynamics?"
- Solution: Forensic methodologies must include 6G network logs, AI-based reconstructions, and real-time network intelligence. Courts may require scientific validation of forensic CSA techniques before accepting 6G-based location evidence.
4. Conclusion
- 6G fundamentally disrupts traditional CSA methodologies, requiring a forensic shift from static RF assumptions to real-time data-driven analysis.
- Historical RFPS methods will no longer be reliable, necessitating AI-enhanced forensic models and network-side data extraction.
- Legal scrutiny of CSA in 6G cases will increase, requiring forensic experts to adapt their techniques to align with new wireless paradigms.
- Future forensic investigations must integrate RIS behaviour, beamfocusing effects, adaptive coverage logs, and real-time propagation adjustments to ensure credibility and accuracy in court.
This intention behind this article's is to serve as an observation post for forensic experts preparing for the 6G era of mobile network investigations. Agreeing or disagreeing with the articles observations is a good community activity and practice and such discussion must not be allowed to be discussed behind closed door when it comes to Cell Site Analysis/Radio Frequency Propagation Surveys (CSA/RFPS). The CSA/RFPS subject matter becomes even more fascinating when assessing 5G having shifted away from 2G, 3G and 4G paradigms
*The research for this article is based upon an initial assessment of the study 'The Road Towards 6G: Opportunities, Challenges, and Applications A Comprehensive View of the Enabling Technologies (Springer 2024)' [ISBN 978-3-031-42566-0 ISBN 978-3-031-42567-7 (eBook) https://doi.org/10.1007/978-3-031-42567-7 Editors: Valeria Loscri; Luca Chiaraviglio; Anna Maria Vegni] and reviewing other sources involved with or relating to CSA/RFPS.
