com.net2plan.libraries

Class WirelessUtils

java.lang.Object

com.net2plan.libraries.WirelessUtils

public class WirelessUtils
extends Object

Class to deal with auxiliary functions to handle wireless networks.

Constructor Summary

Constructors

Constructor and Description
WirelessUtils()

Method Summary

Modifier and Type	Method and Description
static Triple<DoubleMatrix2D,Map<Link,Set<Node>>,Map<Node,Set<Link>>>	computeInterferenceMap(List<Node> nodes, List<Link> links, boolean simultaneousTxAndRxPossible) Given a wireless network where a node cannot simultanously receive signals from two different nodes (or a collision would be produced and no signal is correctly received), this function computes the cases in which a node transmission interferes with a link reception, and returns this information in several structures.
static DoubleMatrix2D	computeInterferenceMatrixNaturalUnits(List<Link> links, double interferenceAttenuationFactor_nu, double pathLossExponent) Computes the interference matrix in a network subject to soft interferences: a matrix with as many rows and columns as links, with the gain in natural units of the signal from origin of e1 to destination of e2.
static double	computeLinkReceivedInterferenceAtMaxPower_nu(int e, double maxTransmissionPower_logu, DoubleMatrix2D Gnu_ee) Returns the maximum possible interference power in natural (linear) units a link can receive, if the rest of the links transmit at its maximum power at the same time.
static DoubleMatrix2D	computeSchedulingMatrix(List<Link> links) Given a wireless network where a node cannot simultanously receive signals from two different nodes (or a collision would be produced and no signal is correctly received), and cannot transmit and receive at the same time, this function computes the scheduling matrix, with one row per link, and one column for each VALID schedule: in a valid schedule, all the links active (with a 1 in the associated row) could simultaneously transmit with no collision.
static double	computeSINRLink(int e, DoubleMatrix1D transmissionPowerLogUnits_e, DoubleMatrix2D Gnu_ee, double receptionThermalNoise_nu) Computes the Signal to Noise Ratio for the given wireless link.
static double	computeWorseReceiverInterferencePower_nu(double maxTransmissionPower_logu, DoubleMatrix2D Gnu_ee) Compute the highest received interference power that a node in the network receives, when all the links are simultaneously transmitting at its maximum power

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WirelessUtils

public WirelessUtils()

Method Detail

computeInterferenceMap

public static Triple<DoubleMatrix2D,Map<Link,Set<Node>>,Map<Node,Set<Link>>> computeInterferenceMap(List<Node> nodes,
                                                                                                    List<Link> links,
                                                                                                    boolean simultaneousTxAndRxPossible)

Given a wireless network where a node cannot simultanously receive signals from two different nodes (or a collision would be produced and no signal is correctly received), this function computes the cases in which a node transmission interferes with a link reception, and returns this information in several structures. A link e is assumed to be interfered by a node n (different to the initial node of e), when the reception node of e (node b(e)) is reachable by n (that is, there is a link from n to b(e)). Also, in those wireless networks for which a node cannot transmit and receive simultaneously, a link e is also interfered by node b(e), since if b(e) transmits link e cannot receive. The interference information is returned in three equivalent structures (they reflect the same information in different forms):

• A DoubleMatrix2D object (a 2D matrix), with as many rows as nodes and as many columns as links. Position (n,e) equals to 1 is the transmission in node n would impede any reception in link e.
• A map Map<Link,Set<Node>> which associates to each link, the set of nodes that interfere to it
• A map Map<Node,Set<Link>> which associates to each node, the set of links that the node interferes to

Parameters:

nodes - List of nodes of the network

links - List of wireless links

simultaneousTxAndRxPossible - Wheter or not simultaneous transmission and reception is possible in the network nodes

Returns:

the interference information in three equivalent structures

computeInterferenceMatrixNaturalUnits

public static DoubleMatrix2D computeInterferenceMatrixNaturalUnits(List<Link> links,
                                                                   double interferenceAttenuationFactor_nu,
                                                                   double pathLossExponent)

Computes the interference matrix in a network subject to soft interferences: a matrix with as many rows and columns as links, with the gain in natural units of the signal from origin of e1 to destination of e2. The power transmitted from the origin of e1 in its travel to the end node of e2 suffers an attenuation given by d^alpha, where d is the distance traversed by the signal and alpha is the path loss exponent characterizing the propagation model. In addition, when link e1 is different to e2, then the received power is actually an interference. In this case, we assume that the receptor of e2 is able to further attenuate by a factor interferenceAttenuationFactor_nu the received power.

Parameters:

links - List of links

interferenceAttenuationFactor_nu - Interference attenuation factor

pathLossExponent - Path loss exponent

Returns:

The interference matrix

computeLinkReceivedInterferenceAtMaxPower_nu

public static double computeLinkReceivedInterferenceAtMaxPower_nu(int e,
                                                                  double maxTransmissionPower_logu,
                                                                  DoubleMatrix2D Gnu_ee)

Returns the maximum possible interference power in natural (linear) units a link can receive, if the rest of the links transmit at its maximum power at the same time.

Parameters:

e - the link

maxTransmissionPower_logu - maximum transmission power of each other link in the network, in logarithmic units

Gnu_ee - The interference map for the network

Returns:

Maximum interference power in natural inuts

computeSchedulingMatrix

public static DoubleMatrix2D computeSchedulingMatrix(List<Link> links)

Given a wireless network where a node cannot simultanously receive signals from two different nodes (or a collision would be produced and no signal is correctly received), and cannot transmit and receive at the same time, this function computes the scheduling matrix, with one row per link, and one column for each VALID schedule: in a valid schedule, all the links active (with a 1 in the associated row) could simultaneously transmit with no collision. A collision occurs in a link e from node a(e) to node b(e), when this link is active, and at the same time any link e' coming out of a node n which can reach to b(e) (has a link to it) is active. Also, those schedules where a node transmits in two links simultanaously, or a node must receive from two links simultaneouly, or a node has to transmit and receive simultaneously, are forbiden.

Parameters:

links - List of wireless links

Returns:

the scheduling matrix

computeSINRLink

public static double computeSINRLink(int e,
                                     DoubleMatrix1D transmissionPowerLogUnits_e,
                                     DoubleMatrix2D Gnu_ee,
                                     double receptionThermalNoise_nu)

Computes the Signal to Noise Ratio for the given wireless link.

Parameters:

e - link index

transmissionPowerLogUnits_e - The vector of transmission power of each link in logarithmic units

Gnu_ee - the interference map of the network: fraction of power in link e1 that reaches the end node of link e2 (and if e1 is not e2, becomes an interference to it)

receptionThermalNoise_nu - the thermal noise at the receptor node of link e

Returns:

the signal-to-noisse-and-interference ratio

computeWorseReceiverInterferencePower_nu

public static double computeWorseReceiverInterferencePower_nu(double maxTransmissionPower_logu,
                                                              DoubleMatrix2D Gnu_ee)

Compute the highest received interference power that a node in the network receives, when all the links are simultaneously transmitting at its maximum power

Parameters:

maxTransmissionPower_logu - maximum transmission power of each link in the network, in logarithmic units

Gnu_ee - The interference map for the network

Returns:

the worst case (highest) interference power