Authors
Amy Babay and Prashant Krishnamurthy
Abstract
We expect future dynamic spectrum sharing regimes to be implemented in a distributed manner to support efficient coordination of spectrum rights between incumbents and secondary nodes. Practical approaches for sharing spectrum include using environmental sensors to detect incumbent transmissions, incumbents informing secondary users of their transmissions, and nodes locally making decisions using location and propagation models. A centralized authority could allocate spectrum slices and transmit powers in time and space to nodes based on rights and interference. But centralization has disadvantages: bottlenecks, delays, vulnerability to failures, and accidental or intentional errors in allocation since decisions still depend on distributed information gathering (environmental sensors, self-reporting by nodes etc.). Distributed coordination (e.g., polycentricity) can alleviate some of these challenges. Yet, distributed coordination between nodes deployed by potentially competing entities with different rights, having differing observations (system state) of interference, or experiencing failures (node crashes, measurement errors, message loss, or even security breaches leading to node compromises) is challenging.
The Byzantine fault model provides a promising approach to reason about such challenges: in this model, a fraction of nodes may behave in arbitrary or even malicious ways. Byzantine Fault Tolerant (BFT) protocols enable correct nodes to make consistent decisions despite arbitrary behavior from a subset of nodes. In this poster we explore a preliminary set of models that we are examining towards mapping spectrum sharing strategies to BFT models that can make spectrum sharing trustworthy.