A Guide to Installing and Configuring APs for a Wireless Solution

Introduction

In today’s fast-paced digital landscape, wireless solutions have become integral to our everyday lives. From homes to businesses, schools to healthcare facilities, the demand for reliable and efficient wireless connectivity has skyrocketed. However, installing and configuring Access Points (APs) for a wireless solution can be a daunting task, especially when dealing with hidden node issues. In this blog, we will delve into what hidden nodes are, why they matter, and how to address them during the installation and configuration of APs for a seamless wireless experience.

Understanding Hidden Nodes

Hidden nodes are a common challenge in wireless networking. They occur when two or more wireless devices, each within the range of an AP, cannot directly communicate with each other due to physical obstructions, signal interference, or simply because they are out of each other’s line of sight. This can lead to packet collisions, performance degradation, and a frustrating user experience.

The figure below shows how nodes PC 1 and PC 2 interact with each other. Each node can hear each other and the AP. When PC 1 is sending data to the AP, PC 2 will back off and wait its turn when there is available airtime.

In the figure below, we can see that while both PC are within range of the AP, they are no longer aware of each other. Both PC’s will compete to send data, but the closer PC will usually win. Nodes with weaker signals will have less airtime and could become completely hidden.

Hidden Node Issues

1. Packet Collisions: Hidden nodes may attempt to transmit data simultaneously, leading to packet collisions. This results in data being lost or corrupted, leading to retransmissions and reduced network efficiency.
2. Performance Degradation: Hidden nodes can significantly degrade network performance, as devices may need to contend for airtime, causing delays and reducing overall throughput.
3. Interference: Hidden nodes often coexist with signal interference, making it difficult for APs and devices to distinguish between legitimate transmissions and noise, further affecting network reliability.

Addressing Hidden Node Issues

To mitigate the hidden node problem, IEEE 802.11 networks use various techniques, including Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA, which we briefly mentioned in our last blog) and the use of Request-to-Send (RTS) and Clear-to-Send (CTS) frames. Modern wireless networking equipment has already implemented these techniques, which has significantly improved the efficiency and reliability of wireless communication. The hidden node problem can still be relevant in certain scenarios, even with modern equipment. Below are some additional things to keep in mind.

1. Environment and Deployment: The hidden node problem can still occur in complex or challenging wireless environments where physical obstacles, interference sources, or signal reflections create conditions where nodes may not be able to detect each other accurately.
2. Network Density: In high-density wireless deployments, where many devices are in close proximity, there is an increased potential for hidden node issues to arise. Despite advanced protocols, collisions can still happen in crowded areas.
3. Mixed Networks: In networks that support both legacy and modern devices, older devices that do not support advanced collision avoidance mechanisms may still experience hidden node issues, potentially affecting the entire network.
4. Interference: External sources of interference, such as neighboring wireless networks or electronic devices, can exacerbate the hidden node problem and lead to unexpected collisions.
5. Configuration and Optimization: Proper network planning, configuration, and optimization are essential to minimize the impact of the hidden node problem. This includes adjusting transmission power levels, channel selection, and other settings to optimize network performance.
6. Site Survey: Before installation, conduct a thorough site survey to identify potential hidden node areas. This involves understanding the physical layout, obstacles, and potential interference sources within the coverage area.

Conclusion

Hidden node issues are a common challenge when installing and configuring APs for wireless solutions. However, with proper planning, site assessment, and smart configuration, you can mitigate these issues and provide users with a reliable and efficient wireless experience. Remember that wireless networking is dynamic, and ongoing monitoring and optimization are crucial for maintaining optimal performance as network conditions change over time. By addressing hidden node issues proactively, you can ensure that your wireless solution remains a vital asset for your organization or home.