ErasureChannel

Interfaces and Buses / Wireless_Sensor / Channels / ErasureChannel
Block Name: ErasureChannel

Direct Known Subclasses:
DelayChannel

public class ErasureChannel
extends VisualSim.simulators.wireless.kernel.AtomicWirelessChannel

Model of a wireless channel with a specified loss probability. If the loss probability is greater than zero then on each call to the transmit() method, for each receiver in range, with the specified probability, the transmission to that receiver will not occur. Whether a transmission occurs to a particular receiver is independent of whether it occurs to any other receiver.

For convenience, a variable named "distance" is available and equal to the distance between the transmitter and the receiver when the lossProbability is evaluated. Thus, the loss probability can be given as an expression that depends on this distance.

The distance between the transmitter and receiver is determined by the protected method _distanceBetween(), which is also used to set the value of the distance variable that can be used in the expression for loss probability. In this base class, that method uses the _location attribute of the transmit and receive actors, which corresponds to the position of the icon in the ModelBuilder visual editor. Subclasses may override this protected method to provide some other notion of distance.

Since:
VisualSim4.0

Field Detail

lossProbability

public VisualSim.data.expr.Parameter lossProbability

The probability that a call to transmit() will fail to deliver the token to a receiver that is in range. This is a double that defaults to 0.0, which means that no loss occurs.

seed

public VisualSim.data.expr.Parameter seed

The seed that controls the random number generation. A seed of zero is interpreted to mean that no seed is specified, which means that each execution of the model could result in distinct data. For the value 0, the seed is set to System.currentTimeMillis() + hashCode(), which means that with extremely high probability, two distinct actors will have distinct seeds. However, current time may not have enough resolution to ensure that two subsequent executions of the same model have distinct seeds. This parameter contains a LongToken, initially with value 0.

distance

public VisualSim.data.expr.Variable distance

A variable that is set to the distance between the transmitter and the receiver before the powerLossFactor expression is evaluated.

_random

protected java.util.Random _random

A random number generator.