Problem Description

The explosive growth of wireless devices and applications has intensified the demand for spectrum, creating severe challenges for accommodating heterogeneous networks within limited frequency bands. Among the most pressing issues is the coexistence of WiFi and LTE systems, both of which are widely deployed and increasingly overlap in unlicensed bands. Conventional spectrum sharing strategies often require explicit coordination mechanisms such as inter-network signaling, centralized schedulers, or tight synchronization across different technologies. While effective in theory, these solutions are difficult to implement in practice because WiFi and LTE are governed by independent standards, operated by different entities, and designed with inherently different medium access mechanisms. As a result, the lack of transparent coexistence solutions has become a critical bottleneck in achieving efficient and scalable spectrum utilization.

Methodology

To address this challenge, we propose a transparent coexistence scheme for WiFi and LTE that does not rely on cross-network coordination or inter-system synchronization. The core enabler of our approach is a blind interference cancellation technique that allows a multi-antenna receiver to decode its intended signal even in the presence of unknown and potentially strong interference from a coexisting network. Unlike coordination-based approaches, this method empowers each network to operate independently, while still ensuring that overlapping transmissions can be effectively separated and decoded. By doing so, our solution reduces protocol overhead, preserves backward compatibility with existing devices, and eliminates the need for complex inter-network agreements.

Design

The design of our scheme builds upon advanced signal processing techniques for interference suppression in multi-antenna systems. At the physical layer, the receiver applies spatial filtering and blind source separation methods to isolate the desired WiFi or LTE signal from interfering transmissions. Crucially, this is achieved without prior knowledge of the interfering signal’s modulation, coding, or protocol structure, making the approach robust to heterogeneous coexistence scenarios. Furthermore, the scheme is designed to adapt to varying channel conditions and interference levels, ensuring reliable decoding even in dense environments where interference is both dynamic and unpredictable.

Validation

To validate the practicality of the proposed scheme, we developed a prototype implementation on a software-defined radio (SDR) testbed. The prototype integrates our blind interference cancellation algorithm with standard WiFi and LTE transceivers, enabling real-time evaluation in an indoor wireless environment. Experimental results demonstrate that the system can sustain reliable data transmission for both WiFi and LTE users under simultaneous operation, thereby confirming the feasibility of transparent coexistence. This proof-of-concept implementation highlights the potential of blind interference cancellation as a scalable and deployable solution for spectrum sharing, paving the way toward more efficient use of unlicensed bands in future wireless networks.