Collaborative Coexistence of Bluetooth LE, BR/EDR, and WLAN Using PHY Packet Traffic Arbitration

Packet Traffic Arbitration

In collaborative coexistence mechanisms, two wireless networks collaborate and exchange network-related information. According to the recommended practices stated in [3], the three collaborative coexistence mechanisms are alternating wireless medium access (AWMA), PTA, and deterministic interference suppression. For more information about coexistence between Bluetooth and WLAN, see Bluetooth-WLAN Coexistence. This example simulates collaborative coexistence between Bluetooth and WLAN by using the PTA mechanism.

The PTA mechanism provides per-packet authorization for all transmissions and receptions. Bluetooth and WLAN technologies collocated in a device can collaboratively coexist by using the PTA mechanism. This example controls the transmission of packets by implementing PTA at the PHY.

In this example, the PTA transmits packets in this priority.

Collaborative Coexistence Scenario

This figure shows a coexistence node consisting of a Bluetooth device and a WLAN device.

In the coexistence node, the PTA controls the communication to and from the Bluetooth and WLAN devices by using a single transmit-receive chain. In the absence of PTA, the Bluetooth and WLAN devices operate using their respective transmit-receive chains. The example creates and configures the coexistence node by performing these steps.

The example simulates this coexistence scenario.

The scenario consists of these nodes.

Check for Support Package Installation

Check if the Communications Toolbox Wireless Network Simulation Library support package is installed. If the support package is not installed, MATLAB® returns an error with a link to download and install the support package.

wirelessnetworkSupportPackageCheck

Create and Configure the Scenario

Set the seed for the random number generator to 1 to ensure repeatability of results. The seed value controls the pattern of random number generation. Initializing the random number generator using the same seed ensures the same result. To improve the accuracy of your simulation results after running the simulation, you can change the seed value, run the simulation again, and average the results over multiple simulations.

rng(1,"twister")

Create a wireless network simulator object.

networkSimulator = wirelessNetworkSimulator.init;

Specify the simulation time in seconds.

simulationTime = 0.5;

Create a multidevice coexistence node. Specify the name and the position of the node in meters.

coexistenceNode = helperCoexNode(Name="CoexNode",Position=[0 0 5]);

Create a WLAN STA device by using the wlanDeviceConfig object. Use the configuration to add the WLAN STA device to the coexistence node.

staDeviceCfg = wlanDeviceConfig(Mode="STA",BandAndChannel=[2.4 1],InterferenceModeling="overlapping-adjacent-channel");
wlanSTADeviceName = addDevice(coexistenceNode,staDeviceCfg);

Create a Bluetooth BR/EDR device configuration. Use the configuration to add the Bluetooth BR/EDR Central device to the coexistence node.

centralBREDRDeviceCfg = helperBluetoothDeviceConfig(Role="central");
centralBRDeviceName = addDevice(coexistenceNode,centralBREDRDeviceCfg);

Create a Bluetooth LE device configuration. Use the configuration to add the Bluetooth LE Central device to the coexistence node.

centralLEDeviceCfg = helperBluetoothLEDeviceConfig(Role="central");
centralLEDeviceName = addDevice(coexistenceNode,centralLEDeviceCfg);

Create and configure a coexistence node with a WLAN AP device.

apDeviceCfg = wlanDeviceConfig(Mode="AP",BandAndChannel=[2.4 1],InterferenceModeling="overlapping-adjacent-channel");
wlanAPNode = helperCoexNode(Name="AP",Position=[20 0 0]);
wlanAPDeviceName = addDevice(wlanAPNode,apDeviceCfg);

Create and configure a coexistence node with a Bluetooth BR/EDR Peripheral device.

peripheralBREDRNode = helperCoexNode(Name="Peripheral BREDR",Position=[10 0 0]);
peripheralBRDeviceName = addDevice(peripheralBREDRNode,helperBluetoothDeviceConfig);

Create and configure a coexistence node with a Bluetooth LE Peripheral device.

peripheralLENode = helperCoexNode(Name="Peripheral LE",Position=[0 0 0]);
peripheralLEDeviceName = addDevice(peripheralLENode,helperBluetoothLEDeviceConfig);

Configure the Connections Between the Devices

Associate the WLAN AP and WLAN STA devices of the coexistence node.

associateStations(wlanAPNode,coexistenceNode);

Configure the connection between the Bluetooth BR/EDR Central and Peripheral devices of the coexistence node.

connectionCfgBREDR = helperBluetoothConnectionConfig;
configureConnection(connectionCfgBREDR,coexistenceNode,peripheralBREDRNode);

Configure the connection between the Bluetooth LE Central and Peripheral devices of the coexistence node.

connectionCfgLE = helperBluetoothLEConnectionConfig;
configureConnection(connectionCfgLE,coexistenceNode,peripheralLENode);

Add Application Traffic

This example consists of only one multidevice coexistence node. If you add traffic between a multidevice coexistence node and a single device coexistence node, the addTrafficSource object function automatically directs the traffic based on the type of the single device. To add traffic between two multidevice nodes, specify the SourceDeviceName name-value argument to the addTrafficSource object function. The value of the SourceDeviceName argument must be the name of the device that the addDevice object function returns.

Configure and add On-Off application traffic at the WLAN AP and STA nodes.

ap2staTraffic = networkTrafficOnOff(DataRate=1000,PacketSize=1200,OnTime=0.1,OffTime=0.1);
addTrafficSource(wlanAPNode,ap2staTraffic,DestinationNode=coexistenceNode)

sta2apTraffic = networkTrafficOnOff(DataRate=1000,PacketSize=1200,OnTime=0.1,OffTime=0.1);
addTrafficSource(coexistenceNode,sta2apTraffic,DestinationNode=wlanAPNode)

Configure and add On-Off application traffic between the Bluetooth BR/EDR Central and Peripheral nodes.

central2PeripheralTrafficBR = networkTrafficOnOff(DataRate=200,PacketSize=27,OnTime=0.1,OffTime=0.1);
addTrafficSource(coexistenceNode,central2PeripheralTrafficBR,DestinationNode=peripheralBREDRNode)

peripheral2CentralTrafficBR = networkTrafficOnOff(DataRate=200,PacketSize=27,OnTime=0.1,OffTime=0.1);
addTrafficSource(peripheralBREDRNode,peripheral2CentralTrafficBR,DestinationNode=coexistenceNode)

Configure and add On-Off application traffic between the Bluetooth LE Central and the Peripheral nodes.

central2PeripheralTrafficLE = networkTrafficOnOff(DataRate=200,PacketSize=27,OnTime=Inf,OffTime=0);
addTrafficSource(coexistenceNode,central2PeripheralTrafficLE,DestinationNode=peripheralLENode)

peripheral2CentralTrafficLE = networkTrafficOnOff(DataRate=200,PacketSize=27,OnTime=Inf,OffTime=0);
addTrafficSource(peripheralLENode,peripheral2CentralTrafficLE,DestinationNode=coexistenceNode)

Attach PTA

To add a PTA to the multidevice coexistence node, set the enablePTA flag to true.

enablePTA = true;

Add a PTA to the coexistence node by using the addPTA object function.

if enablePTA
    ptaHandle = @(coexObj,currentTime) helperPHYPTAModule(coexObj,currentTime);
    addPTA(coexistenceNode,ptaHandle)
end

Simulation and Results

Add all the nodes to the wireless network simulator.

addNodes(networkSimulator,[coexistenceNode peripheralBREDRNode wlanAPNode peripheralLENode])
nodes = networkSimulator.Nodes;

Configure Packet Communication and Node Performance Visualization

To visualize packet communication in all the nodes, set the enablePacketVisualization flag to true. The visualization shows these plots.

At the end of the simulation, you can visualize packets at any time instance.

enablePacketVisualization = true;

To display the visualization at the end of simulation, specify the VisualizeAtEnd name-value argument and set to true.

if enablePacketVisualization
    packetVisObj = helperPlotPacketTransitions(nodes,simulationTime,VisualizeAtEnd=false);
end

To view the node performance visualization, set enableNodePerformancePlot to true. The visualization displays the packet loss ratio, throughput, and latency of the Bluetooth BR/EDR, Bluetooth LE, and WLAN nodes at the end of simulation.

enableNodePerformancePlot = true;

Initialize the visualization of the node performance plot.

if enableNodePerformancePlot
    performancePlotObj = helperVisualizePerformance(nodes,simulationTime);
end

Run the Simulation

Run the simulation for the time specified and generate these results.

run(networkSimulator,simulationTime)

Statistics

Retrieve the statistics of all the nodes. In the coexistence node, the Bluetooth BR/EDR, Bluetooth LE, and WLAN node statistics are present in their corresponding device structures. For more information about Bluetooth BR/EDR and LE node statistics, see Bluetooth BR/EDR Node Statistics (Bluetooth Toolbox) and Bluetooth LE Node Statistics (Bluetooth Toolbox), respectively. For more information about WLAN node statistics, see WLAN System-Level Simulation Statistics.

coexNodeStats = statistics(coexistenceNode);
peripheralBREDRStats = statistics(peripheralBREDRNode);
peripheralLEStats = statistics(peripheralLENode);
apStats = statistics(wlanAPNode);

Further Exploration

You can use this example to further explore these capabilities.

Capture IQ Samples

Capture the IQ samples of the nodes by using the helperCaptureIQSamples helper object. To capture the IQ samples of the nodes, uncomment and add this code before you run the wireless network simulator.

% iqSampleObj = helperCaptureIQSamples(coexistenceNode);

At the end of the simulation, the simulation stores the IQ samples of the corresponding nodes in a MAT file with the filename format NodeName_NodeID_yyyyMMdd_HHmmss.mat, where:

The IQSamples property of the iqSampleObj object contains the captured IQ samples. A MAT file corresponding to each node stores the captured IQ samples. If the network contains several nodes or when the simulation time is long, the process of capturing the IQ samples consume significant memory. The MAT file generated at the end of the simulation can consume significant disk space. For example, a system-level simulation that captures 100 million IQ samples creates a MAT file of approximate size 1.5 GB.

To visualize the captured IQ samples, use the Signal Analyzer app. Uncomment and add the code after running the simulation.

% iqSamples = iqSampleObj.IQSamples;
% for deviceIdx = 1:numel(iqSamples)
%     signalAnalyzer(iqSamples(deviceIdx));
% end

Add Mobility to Nodes

You can add mobility to any node by using the addMobility object function. To add mobility to the coexistence node, uncomment and add this code before you run the wireless network simulator.

% addMobility(coexistenceNode,BoundaryShape="rectangle")

Add Antenna Isolation

Antenna isolation is the isolation between the antennas in the transmit-receive chains present in the same coexistence node. Isolation between two antennas minimizes the interference on each antenna caused by the adjacent antenna. To add antenna isolation between the transmit-receive chains in a coexistence node, use the configureAntennaIsolation object function of the helperCoexNode helper object. Uncomment and add this code before you run the wireless network simulator.

% isolationPower = 20; % In dB
% configureAntennaIsolation(coexistenceNode,isolationPower)

Appendix

The example uses these helpers:

References