Wireless sensor networks (WSNs) are composed of sensor nodes and sinks. Sensor nodes have the capability of self-healing and self-organizing. They are decentralized and distributed in nature where communication takes place via multihop intermediate nodes. The main objective of a sensor node is to collect information from its surrounding environment and transmit it to the sink. WSNs have many applications and are used in scenarios such as detecting climate change, monitoring environments and habitats, and various other surveillance and military applications. Mostly sensor nodes are used in such areas where wired networks are impossible to be deployed. WSNs are deployed in physical harsh and hostile environments where nodes are always exposed to physical security risks damage.

In this special issue, we concentrate mainly on Quality of Service (QoS) based cooperative communication and advanced security mechanisms for wireless sensor network. We are interested in novel ideas, advanced techniques, comparative analysis of different methodologies, detailed surveys, and technical reviews on all aspects of QoS based cooperative communications and security mechanisms in wireless sensor networks. This special issue covers industrial applications and academic research contributions.

Potential topics include but are not limited to the following:

• Green wireless sensor networks architectures and communication protocols
• Context and location aware applications
• Data gathering, fusion, and dissemination in WSNs
• Operating system and middleware support
• Multimedia over sensor networks
• Smart cities and smart environment
• Cooperative communication
• Relaying techniques
• Attacks and countermeasures
• Security tools
• Cross layer security mechanisms
• Authentication and key management
• Intrusion detection systems
• Security policies and information hiding
• Privacy and anonymity
• Active, passive, and denial of service (DoS) attacks
• Secure routing protocols