What Is a Wi-Fi Access Point?

A Wi-Fi access point (AP) is a hardware device that creates a wireless local area network (WLAN), allowing Wi-Fi stations to connect to the network.

While this definition appears straightforward, several factors must be considered when designing an embedded system that includes Wi-Fi access point functionality.

Key Design Considerations

The appropriate AP architecture depends on multiple system requirements, including:

• Number of station devices to be connected
• Number of SSIDs required
• Support for the latest Wi-Fi PHY/MAC features:
  • Multi-Link Operation (MLO)
  • Preamble Puncturing
  • Multi-Resource Unit (MRU)
  • Restricted Target Wake Time (r-TWT)
• AP-specific features:
  • IEEE 802.11k/r/v roaming support
  • SSID-to-VLAN mapping
• Physical size constraints
• Operating frequency bands
• Concurrent station-mode support

Full-Featured AP Module vs. SoftAP

A common misconception is that an AP-capable station module can provide the same functionality as a dedicated access point. In practice, there are significant differences.

Dedicated AP Module

A dedicated AP module is designed and optimized specifically for access point operation.

Typical characteristics:

• Supports 100+ client devices per frequency band
• Optimized throughput and airtime efficiency
• Supports multiple SSIDs
• Advanced AP MAC features
  • OFDMA
  • MLO
  • Preamble Puncturing
  • MRU
• IEEE 802.11r fast roaming support
• High-performance and scalable WLAN operation

SoftAP on a Station Module

SoftAP (Software Access Point) functionality is provided by a Wi-Fi station device operating in AP mode.

Typical characteristics:

• Supports approximately 16 to 32 client devices, depending on the module
• Lower throughput due to host CPU processing overhead and host interface limitations
• Supports simultaneous station and AP operation
• Frequently integrated with Bluetooth Low Energy (BLE)
• Typically lacks advanced AP features such as:
  • OFDMA in AP mode
  • MLO in AP mode
  • Preamble Puncturing in AP mode
  • MRU in AP mode
• Usually supports only a single SSID
• Generally does not support IEEE 802.11r AP functionality

Choosing Between Dedicated AP and SoftAP

When to Use a Dedicated AP Module

A dedicated AP module is recommended when:

• Large numbers of client devices must be supported
• Wireless performance is mission-critical
• Roaming support is required
• Multiple SSIDs are needed
• The latest Wi-Fi features should be fully utilized
• End-user network infrastructure cannot be controlled

In such cases, the entire solution may be delivered as a package consisting of:

• Embedded station devices
• A dedicated access point or gateway device

This approach ensures that the system can consistently take advantage of the latest Wi-Fi technologies and provide predictable wireless performance.

When to Use SoftAP

SoftAP is generally more suitable for embedded devices that occasionally need to create a small wireless network.

Typical use cases include:

• Initial device configuration
• Device provisioning
• Maintenance operations
• Temporary peer-to-peer connectivity
• Small-scale wireless networks

Silex Access Point Modules

Silex currently offers three dedicated AP modules.

Building a Tri-Band Access Point

The SX-PCEBE-AP and SX-PCEAX-AP are dual-band AP modules supporting 2.4 GHz and 5 GHz operation.

The SX-PCEAX-AP6E is a dedicated 6 GHz AP module.

To implement a tri-band access point or gateway supporting:

• 2.4 GHz
• 5 GHz
• 6 GHz

two AP modules are required.

Why Choose SX-PCEBE-AP?

The SX-PCEBE-AP introduces several Wi-Fi 7 technologies that can significantly improve wireless reliability and efficiency compared to Wi-Fi 6 solutions.

Key advantages include:

Multi-Link Operation (MLO)

Enables simultaneous use of multiple frequency bands, improving reliability, reducing latency, and increasing throughput.

Preamble Puncturing

Allows efficient use of partially occupied channels, improving spectrum utilization.

Multi-Resource Unit (MRU)

Enhances OFDMA efficiency and improves overall network capacity.

Together, these technologies provide a more robust and efficient wireless experience when paired with Wi-Fi 7 client devices.

Form Factor Considerations

Module size may also influence the platform architecture.

The SX-PCEBE-AP uses a proprietary M.2 Key-E form factor and requires a 5 V power supply for its RF front-end module.

Designers should evaluate:

• Available board space
• Connector requirements
• Power budget
• Thermal design constraints

when selecting the most appropriate AP module.

Summary

The choice between a dedicated AP module and SoftAP should be driven by the role of Wi-Fi within the system architecture.

• Use SoftAP when AP functionality is secondary and only needed for provisioning, maintenance, or small-scale connectivity.
• Use a dedicated AP module when Wi-Fi infrastructure is a core component of the product and advanced wireless performance, scalability, roaming, and the latest Wi-Fi features are required.

For systems requiring the highest level of reliability and performance, dedicated AP modules such as the SX-PCEBE-AP, SX-PCEAX-AP6E, and SX-PCEAX-AP provide a purpose-built foundation for modern wireless networking.