Lossy Channel Games under Incomplete Information

TL;DR

This paper studies lossy channel games with incomplete information, modeling unreliable communication protocols, and shows decidability results for safety and reachability conditions with finite message alphabets.

Contribution

It introduces a formal model for lossy channel games under incomplete information and proves decidability of safety and reachability objectives in this setting.

Findings

Decidability of safety and reachability games with finite message alphabets.

Finite-state observation-based strategies can be effectively computed.

Undecidability results for parity objectives in similar settings.

Abstract

In this paper we investigate lossy channel games under incomplete information, where two players operate on a finite set of unbounded FIFO channels and one player, representing a system component under consideration operates under incomplete information, while the other player, representing the component's environment is allowed to lose messages from the channels. We argue that these games are a suitable model for synthesis of communication protocols where processes communicate over unreliable channels. We show that in the case of finite message alphabets, games with safety and reachability winning conditions are decidable and finite-state observation-based strategies for the component can be effectively computed. Undecidability for (weak) parity objectives follows from the undecidability of (weak) parity perfect information games where only one player can lose messages.