WLAN Node Composition and Configuration

This topic gives an overview of the composition and configuration of a WLAN node. The Node Composition section describes the node composition by mapping the layers and functionalities of a WLAN node with corresponding helper objects. The Node Configuration section describes different configuration parameters related to the node, physical layer (PHY), medium access control (MAC) layer, application layer (APP), channel, and mesh that facilitates transmissions and receptions.

Node Composition

WLAN system-level simulation begins by creating nodes using the hCreateWLANNodeshelper function. This function creates a set of WLAN nodes, each consisting of the APP, MAC, PHY, and channel.

To model the APP functionality of a WLAN node, hCreateWLANNodes uses the hApplication helper object.
To model the MAC layer functionality of a WLAN node, hCreateWLANNodes uses the hEDCAMAC helper object. To implement functionalities like round-robin scheduling, MAC queue management, power control algorithm, and rate control algorithms, the hEDCAMAC helper object uses the hSchedulerRoundRobin, hMACQueueManagement, hPowerControlFixed, hRateControARF (autorate fallback (ARF) algorithm), and hRateControlFixed (fixed-rate control algorithm) helper objects, respectively.
To model the PHY transmitter and receiver, hCreateWLANNodes uses the hPHYTxAbstract and hPHYRxAbstract helper objects, respectively. To model interference, hCreateWLANNodes uses the hInterference helper object. The hCreateWLANNodes helper function creates a channel link quality model by using the hTGaxLinkQualityModel helper object.
To model the wireless channel, hCreateWLANNodes uses the hChannel helper object.

This figure shows the WLAN node composition by mapping the APP, MAC, PHY, and channel functionalities of a WLAN node with the corresponding helper objects.

This table describes the functionalities of the helper functions and objects that are used in the WLAN system-level simulation.

Helper Function or Object or Class	Description
`hWirelessNetworkSimulator`	Simulate wireless network.
`hWirelessNode`	Create a base class for nodes in a wireless network.
`hWLANNode`	Create a WLAN node object consisting of APP, MAC, PHY and channel and interference modeling. You can have multiple interfaces, each with a corresponding PHY, MAC, and channel. Add the interfaces by using the `addInterface` function.
`hCreateWLANNodes`	Create WLAN nodes with specified configuration parameters.
`hApplication`	Create a WLAN APP object.
`hEDCAMAC`	Create a WLAN enhanced distributed channel access (EDCA) MAC object.
`hSchedulerRoundRobin`	Create a round-robin scheduler object.
`hMACQueueManagement`	Create a WLAN MAC queue management object.
`hPowerControl`	Create a base class to implement a power control algorithm. This class defines an interface supported for power control.
`hPowerControlFixed`	Create a fixed transmit power selection object
`hRateControl`	Create a base class to implement a rate control algorithm. This class defines an interface supported for rate control.
`hRateControlARF`	Create an object providing functionality for the ARF algorithm .
`hRateControlFixed`	Create a fixed-rate selection object.
`hPHYRxInterface`	Create a WLAN PHY receiver interface class. This interface class acts as a base class for all the PHY types. This class defines an interface to the PHY receiver. In this class, you can set the properties and methods to interact with the higher layers.
`hPHYRxAbstract`	Create a WLAN abstracted PHY receiver object for PHY decoding.
`hPHYRx`	Create a WLAN PHY receiver object for PHY decoding.
`hInterference`	Create an object to model interference at the PHY.
`hTGaxLinkQualityModel`	Create a link quality model object. This model estimates the signal-to-interference noise ratio (SINR) for an 802.11ax SU link assuming perfect synchronization.
`hPHYTxInterface`	Create a WLAN PHY transmitter interface class. This interface class acts as a base class for all PHY transmitters. This class defines an interface to the PHY transmitter. In this class, you can set the properties and methods to interact with the higher layers.
`hPHYTxAbstract`	Create an object for the WLAN abstracted PHY transmitter. The object creates a WLAN PHY transmitter object that supports these operations: Handling requests from the MAC layer Creating an abstracted waveform (PHY protocol data unit (PPDU)) Handling transmit power (Tx power)
`hPHYTx`	Create an object for the WLAN PHY transmitter. The object creates a WLAN PHY transmitter object that supports these operations: Handling requests from the MAC layer Creating a waveform (PPDU) Handling transmit power (Tx power)
`hChannel`	Create an object for the WLAN channel.
`hStatsLogger`	Create a class to log and visualize statistics. This class implements the functionality to plot the statistics at the end of the simulation.

To access the helper files, add the mlWLANSystemSimulation folder to the MATLAB^® path.

addpath(genpath(fullfile(pwd,'mlWLANSystemSimulation')));

Node Configuration

The WLAN node configuration includes configuring the APP traffic and node-related parameters. To explore the APP, MAC, and PHY configuration, use the hConfigurationHelp helper function.

APP Traffic Configuration

To configure the APP layer at a node, configure the APP traffic fields in the wlanTrafficConfig structure. To configure multiple applications in the network, follow these steps.

Replicate the wlanTrafficConfig structure.
Configure each structure with the desired values of SourceNode and DestinationNode fields.

This table defines the APP traffic configuration fields at a WLAN node.

Fields	Description	Valid Values	Default Value
`SourceNode`	Name of the node that transmits the packet and at which the application is running	Character vector or string scalar that matches a valid node name	`'Node1'`
`DestinationNode`	Name of the node to which the packet originated at `SourceNode` is intended	Character vector or string scalar that matches a valid node name To configure broadcast traffic, set this field to `'broadcast'`	`'Node2'`
`PacketSize`	Size of the generated application packets	Integer in the range [1, 2034]	`1500`
`DataRateKbps`	Rate, in Kbps, at which the application packets are generated	Numeric scalar	`6,00,000`
`AccessCategory`	Access category (AC)	Nonnegative integer in the range [0,3] `0` for best-effort traffic (BE) `1` for background traffic (BK) `2` for video traffic (VI) `3` for voice traffic (VO)	`0`

To view the APP traffic configuration fields of a WLAN node, enter this command at the MATLAB command prompt.

hConfigurationHelp('wlanTrafficConfig')

Node Parameters

This table defines the fields to configure WLAN node parameters.

Fields Description Valid Values Default Value

Fields	Description	Valid Values	Default Value
`NodeName`	Name of the node	Character vector or string scalar If you do not configure this field, the default format of this field is `'NodeX'`, where X is the node identifier (ID)	`''`
`NodePosition`	Position, in meters, of the node in Cartesian coordinates	Three-element vector of elements corresponding to the (x, y, z) point	`[0 0 0]`

NodeName

Name of the node

Character vector or string scalar

If you do not configure this field, the default format of this field is 'NodeX', where X is the node identifier (ID)

''

NodePosition

Position, in meters, of the node in Cartesian coordinates

Three-element vector of elements corresponding to the (x, y, z) point

[0 0 0]

MAC, PHY, and Channel Configuration

To configure the MAC, PHY, and channel at a WLAN node, configure the fields in the wlanNodeConfig structure. To configure multiple nodes in the network, you must replicate the wlanNodeConfig structure. Then, you can customize the node configuration fields for any node in the network.

This table shows the configurable fields at the MAC layer of a WLAN node.

Fields	Description	Valid Values	Default Value
`TxFormat`	Format used for frame transmission	`"NonHT"` `"HTMixed"` `"VHT"` `"HE_SU"` `"HE_EXT_SU"` To configure this field, see the `hFrameFormats` helper class.	`"HE_SU"`
`Bandwidth`	Channel bandwidth, in MHz	`20`, `40`, `80`, or `160`	`20`
`TxMCS`	Modulation and coding scheme (MCS) index for transmitting the frame. To enable this field, set `RateControl` field to `"FixedRate"`.	When you set `TxFormat` field to `"HE_SU"`, the valid values are integers in the range [0, 11]. When you set `TxFormat` field to `"HE_EXT_SU"`, the valid values are in the range [0, 2]. When you set `TxFormat` field to `"VHT"`: If `Bandwidth` is `20` MHz and `TxNumSTS` field is `3` or `6`, the valid values are integers in the range [0, 9]. Otherwise, the range is [0, 8]. If `Bandwidth` is `40` MHz, the valid values are integers in the range [0, 9]. If `Bandwidth` is `80` MHz and `TxNumSTS` field is not `3`, `6`, or `7`, the valid values are integers in the range [0, 9]. If `Bandwidth` is `80` MHz and `TxNumSTS` fiield is `3` or `7`, the valid values are integers in the range [0, 9] excluding 6. If `Bandwidth` is `80` MHz and `TxNumSTS` field is `6`, the valid values are integers in the range [0, 8]. If `Bandwidth` is `160` MHz and `TxNumSTS` field is 3, the valid values are integers in the range [0, 8]. Otherwise, the range is [0, 9]. When you set `TxFormat` field to`"HTMixed"` or `"NonHT"`, the valid values are integers in the range [0, 7]. When you set `TxFormat` field is set to `"HTMixed"`, any input in the range [0, 7] is automatically mapped to an integer in the range [0, 31] based on the NumTxChains field value.	`7`
`TxNumSTS`	Number of space-time streams (STS)	When you set the `TxFormat` field to `"VHT"` or `"HE_SU"`, the valid values are in the range [1, 8]. When you set the `TxFormat` field to `"HTMixed"`, the valid values are in the range [1, 4]. When you set the `TxFormat` field to `"HE_EXT_SU"`, the valid values are in the range [1, 2]. When you set the `TxFormat` field to `"NonHT"`, the valid value is 1. The value of this field must be less than or equal to the `NumTxChains` field value. If the value of this field equals the `NumTxChains` field value, the STS are directly mapped to transmit chains. When you set, The `TxFormat` field to `"VHT"`, `"HE_EXT_SU"`, `"HTMixed"`, or `"HE_SU"` and The value of this field less than the `NumTxChains` field value the STS are mapped to transmit chains using a Fourier matrix.	`1`
`NumTxChains`	Number of transmit chains used during the transmission	When you set `TxFormat` field to `"VHT"` or `"HE_SU"`, the valid values are integers in the range [1, 8]. When you set `TxFormat` field to `"HTMixed"`, the valid values are integers in the range [1, 4]. When you set `TxFormat` field to `"HE_EXT_SU"`, the valid values are integers in the range [1, 2]. When you set `TxFormat` field to `"NonHT"`, the valid values are integers in the range [1, 8].	`1`
`MPDUAggregation`	Flag to enable or disable MAC protocol data unit (MPDU) aggregation	When you set `TxFormat` to `"HTMixed"`, the valid values are a logical `1` (`true`) or `0` (`false`). When you set `TxFormat` to `"VHT"`, `"HE_SU"`, or `"HE_EXT_SU"`, this field is read-only and its value is a logical `1` (`true`). When you set `TxFormat` to `"NonHT"`, this field is read-only and its value is a logical `0` (`false`).	`true`
`DisableAck`	Flag to indicate that the transmitting node does not solicit acknowledgment for the data frame	logical `1` or (`true`) or `0` or (`false`)	`0` or (`false`)
`MaxSubframes`	Maximum number of subframes that can be aggregated in the aggregate-MPDU (A-MPDU)	Integer in the range [1, 256]	`64`
`RTSThreshold`	Threshold length of the frame below which the node does not use request to send/clear to send (RTS/CTS) protection for data transmission To enable this field, set the `DisableRTS` field value to `0` or (`false`).	Integer in the range [0, 65,536]	`65,536`
`DisableRTS`	Flag to enable or disable the RTS/CTS exchange for data transmissions	logical `1` or (`true`) or `0` or (`false`)	`0` or (`false`)
`MaxShortRetries`	Retry limit for frames less than or equal to RTS threshold	Integer in the range [1, 255]	`7`
`MaxLongRetries`	Retry limit for frames greater than the RTS threshold	Integer in the range [1, 255]	`7`
`BasicRates`	Non-HT rates, in Mbps, supported by all the nodes in the network to transmit control frames	Row vector of data rate values from the set {6, 9, 12, 18, 24, 36, 48, 54}.	`[6 12 24]`
`Use6MbpsForControlFrames`	Flag to indicate the use of 6 Mbps data rate for all control frames, ignoring the values in the `BasicRates` set	logical `1` or (`true`) or `0` or (`false`)	`0` or (`false`)
`BandAndChannel`	Operating band and channel number	Cell array of a vector in the form {[x, y]}, where x is a frequency band of 2.4, 5, or 6 GHz and y is any valid channel number. The value of x can be 2.4, 5, or 6. The value of y can be any valid channel number.	`[2.4, 6`]
`CWMin`	Minimum value of the contention window range for each AC	Four-element row vector of elements that are integers in the range [1, 1023], where each element indicates a value of an AC	`[15 15 7 3]`
`CWMax`	Maximum value of the contention window range for each AC	Four-element row vector of elements that are integers in the range [1, 1023], where each element indicates a value of an AC	`[1023 1023 15 7]`
`AIFSSlots`	Number of arbitrary interframe space (AIFS) slots for each AC	Four-element row vector of elements that are integers in the range [2, 15], where each element indicates number of AIFS slots for four ACs	`[3 7 2 2]`
`RateControl`	Rate control algorithm	`"FixedRate"` or `"ARF"`	`“FixedRate”`
`PowerControl`	Power control algorithm	`"FixedPower"`	`“FixedPower”`
`MaxDLStations`	Maximum number of stations (STAs) that can be scheduled for a downlink (DL) multiuser (MU) transmission	If you set the `Bandwidth` field to 20 MHz, the valid values are integers in the range [1, 9]. If you set the `Bandwidth` field to 40 MHz, the valid values are integers in the range [1, 18]. If you set the `Bandwidth` field to 80 MHz, the valid values are integers in the range [1, 37]. If you set the `Bandwidth` field to 160 MHz, the valid values are integers in the range [1, 74].	`1`
`DLOFDMAFrameSequence`	Type of frame exchange sequence to be used in DL orthogonal frequency-division multiple access (OFDMA) MU transmissions	If you want to use DL MU frames with trigger response scheduling (TRS) control and uplink (UL) block ACK (BA) sequence, the valid value is 1. If you want to use DL MU frames with MU block ACK request (BAR) trigger and UL BA sequence, the valid value is 2.	`1`
`IsAP`	Flag to indicate whether a node is an access point (AP)	If the node has single interface, the valid values are logical `1` or (`true`) or `0` or (`false`) If the node has multiple interfaces, the valid value is a vector with element values logical `1` or (`true`) or `0` or (`false`) To configure AP in a particular interface of the node, set the element corresponding to the interface as `1` or (`true`).	`0` or (`false`)
`IsMeshNode`	Flag to indicate whether a node is a mesh node	If the node has single interface, the valid values are logical `1` or (`true`) or `0` or (`false`) If the node has multiple interfaces, the valid value is a vector with element values logical `1` or (`true`) or `0` or (`false`) To enable mesh functionality in a particular interface of the node, set the element corresponding to the interface as `1` or (`true`).	`0` or (`false`)

This table shows the configurable fields at the PHY layer of a WLAN node.

Fields	Description	Valid Values	Default Value
`TxPower`	Transmit power, in dBm	Numeric scalar	`15`
`TxGain`	Transmit gain, in dB	Numeric scalar	`1`
`RxGain`	Receive gain, in dB	Numeric scalar	`0`
`EDThreshold`	Energy detection threshold, in dBm	Numeric scalar	`-82`
`RxNoiseFigure`	Receiver noise figure, in dB	A scalar number specifying the noise figure in dB	`7`

This table shows the channel configuration fields at a WLAN node.

Fields	Description	Valid Values	Default Value
`ReceiverRange`	Distance, in meters, beyond which the receiver ignores signal to reduce the simulation complexity	Numeric scalar	`1000`
`FreeSpacePathloss`	Flag to enable or disable free space pathloss	logical `1` or (`true`) or `0` or (`false`)	`1` or (`true`)

This table shows the mesh configuration fields at a WLAN node.

Fields	Description	Valid Values	Default Value
`MeshTTL`	Maximum number of hops allowed to forward a packet in the mesh network	Integer in the range [1, 255]	`31`

To view the PHY, MAC, channel, and mesh configuration fields of a WLAN node, enter this command at the MATLAB command prompt.

hConfigurationHelp('wlanNodeConfig')