Composition of WLAN Nodes

You can create access points (APs), stations (STAs), or mesh stations with WLAN Toolbox™ by using the wlanNode object. These WLAN nodes contain the traffic manager and protocol stacks comprising the medium access control (MAC) and physical (PHY) layers, as illustrated in this figure. This topic outlines the functionalities of the different layers implemented by the wlanNode object.

Traffic

The traffic manager includes a collection of traffic pattern objects. The Communications Toolbox™ Wireless Network Simulation Library provides these kinds of application traffic pattern objects to model real-world data traffic:

networkTrafficOnOff — Generates a traffic pattern with two states: on and off.
networkTrafficFTP — Generates a file transfer protocol (FTP) application traffic pattern.
networkTrafficVoIP — Generates a voice over internet protocol (VoIP) application traffic pattern.
networkTrafficVideoConference — Generates a video conference application traffic pattern.

Use the addTrafficSource function to add the data traffic source to a WLAN node. The AccessCategory name-value argument of the addTrafficSource function enables you to set the priority of the traffic.

In addition to these traffic pattern objects, WLAN nodes support full-buffer traffic. This configuration keeps MAC queues constantly filled with frames for transmission. To configure the full-buffer traffic, use the FullBufferTraffic name-value argument of the associateStations function.

MAC Layer

The MAC layer of a WLAN node has these key functionalities.

Enhanced distributed channel access (EDCA), which performs these key operations.
- Prioritized quality of service (QoS) management — Prioritizes traffic through per-access category queue management, and sets different contention parameters for each access category, such as the minimum and maximum contention window sizes and the arbitration inter-frame space (AIFS).
- Multi-Frame Transmit Opportunity (TXOP) — Allows a device to transmit multiple data frames in succession once it gains access to the communication channel after a single request to send (RTS) and clear to send (CTS) exchange.
- Frame transmission and reception — Manages various frame types, including RTS, CTS, beacon, data, trigger, acknowledgment, and block acknowledgment.
- Acknowledgment tracking — Tracks the acknowledgment status of data frames with a detailed block acknowledgment scoreboard.
- Duplicate detection — Uses sequence numbers for duplicate detection.
- Error recovery mechanism— Introduces a calculated delay before the next transmission by employing the extended inter-frame space (EIFS) after detecting corrupted frames.
- Frame retransmission — Retransmits unacknowledged data frames.
Aggregation and de-aggregation — Combines multiple data frames into a single frame for transmission, and separates aggregated frames back into individual data frames upon reception.
Physical and Virtual Carrier Sense — Processes clear channel assessment (CCA) indications and manages the network allocation vector (NAV).
Scheduling — Offers scheduling opportunities to stations, and oversees Resource Unit (RU) allocation for both downlink and uplink orthogonal frequency-division multiple access (OFDMA) transmissions. It prioritizes frames designated for retransmission over those for new transmissions.
Mesh forwarding — Forwards data frames over multiple hops within a mesh network. For more information about mesh forwarding, see the Simulate an 802.11ax Hybrid Mesh Network example.

Use the wlanDeviceConfig object to configure the key functionalities of the MAC layer of a WLAN node.

For information on the MAC layer of a WLAN device that supports multi-link operations (MLOs), see Multi-Link Architecture.

PHY Layer

The wlanNode object supports these types of physical layer processing: full PHY and abstracted PHY. You can use the PHYAbstractionMethod property of the wlanNode object to select abstracted PHY or full PHY processing. Note that all the WLAN nodes in a network must use the same PHY abstraction method.

For more information about WLAN PHY modelling, see Get Started with WLAN System-Level Simulation in MATLAB.

Full PHY

The full PHY simulation models physical protocol data unit (PPDU) operations, including waveform generation and decoding. In full PHY mode, WLAN Toolbox supports interference models such as co-channel, overlapping, and non-overlapping adjacent channel interference. For information about these interference models, see InterferenceModeling property of the wlanDeviceConfig object.

Abstracted PHY

The wlanNode object supports these kinds of abstracted PHY.

TGax evaluation methodology — Employs packet error rate (PER) tables and probabilistic packet failure models to estimate the performance of the PHY layer, as described in the IEEE^® 802.11ax™ evaluation methodology.
TGax MAC calibration — Focuses on MAC layer calibration within the IEEE 802.11ax framework.

For more information about the abstracted PHY, see the Physical Layer Abstraction for System-Level Simulation example.

For information on the PHY layer of a WLAN device that supports MLOs, see Multi-Link Architecture.

Multi-Link Architecture

WLAN Toolbox offers these modes of MLO, namely simultaneous transmit and receive (STR), and enhanced multi-link single radio (EMLSR). The STR mode allows a device to simultaneously transmit and receive data across multiple communication links. Conversely, the EMLSR mode improves a single radio's ability to handle multiple links by enabling the device to transmit or receive data on one link at a time. For more information about these modes, see the 802.11be System-Level Simulation Using STR Multi-Link Operation example.

In IEEE 802.11be™ MLOs, the MAC architecture integrates a shared control mechanism for managing common aspects across all links, while enabling independent operation of MAC modules on each link, as illustrated in this figure.

In MLOs, the division of MAC layer functionalities falls into these distinct categories: Shared-MAC layer functions and independent, link-specific MAC modules.:

These are the key shared-MAC layer functions:
- Sequence numbering — Preserves the correct sequence of frames for reliable communication.
- Queue management — Holds packets received from higher layers in queues.
The key independent link-specific MAC functionalities includes EDCA, aggregation, physical and virtual carrier sense, and scheduling. For more information about these functionalities, see MAC Layer.

When configuring multi-link devices (MLDs) in WLAN systems using WLAN Toolbox, you can adjust settings at the link-level or device-level. Use the wlanLinkConfig object to set the link-level configuration, and use the wlanMultilinkDeviceConfig object to set the device level configuration.