# Channels with Cooperation Links that May Be Absent

## TL;DR

This paper investigates communication networks with cooperation links that may be intermittently available, proposing coding schemes that adapt to the presence or absence of these links to maintain performance.

## Contribution

It introduces models for networks with potentially absent cooperation links and develops coding schemes that adaptively utilize available links to optimize communication.

## Key findings

- Coding schemes perform well when cooperation links are present.
- Schemes degrade gracefully when cooperation links are absent.
- The model accounts for dynamic and unpredictable network conditions.

## Abstract

It is well known that cooperation between users in a communication network can lead to significant performance gains. A common assumption in past works is that all the users are aware of the resources available for cooperation, and know exactly to what extent these resources can be used. Unfortunately, in many modern communication networks the availability of cooperation links cannot be guaranteed a priori, due to the dynamic nature of the network. In this work a family of models is suggested where the cooperation links may or may not be present. Coding schemes are devised that exploit the cooperation links if they are present, and can still operate (although at reduced rates) if cooperation is not possible.