Table Of Contents
Table Of Contents

Modeling Power Consumption

Overview

Modeling power consumption becomes more and more important with the increasing number of embedded devices and the upcoming Internet of Things. Mobile personal medical devices, large-scale wireless environment monitoring devices, electric vehicles, solar panels, low-power wireless sensors, etc., require paying special attention to power consumption. High-fidelity simulation of power consumption allows designing power-sensitive routing protocols, MAC protocols with power management features, etc., which in turn results in more energy-efficient devices.

In order to help the modeling process, the power model is separated from other simulation models in the INET Framework. This separation makes the power model extensible, and it also allows easy experimentation with alternative implementations. In a nutshell, the power model consists of the following components:

  • energy consumption models

  • energy generation models

  • temporary energy storage models

The power model elements fall into two categories, which have Ep and Cc as part of their names:

  • Ep models are simpler and deal with energy and power quantities.

  • Cc models are more realistic and deal with charge, current, and voltage quantities.

The following sections provide a brief overview of the power model.

Energy Consumer Models

Energy consumer models describe the energy consumption of devices over time. For example, energy is consumed when a transceiver transmits or receives a signal, when a CPU forwards a packet, or when a display is turned on.

In INET, an energy consumer model is an OMNeT++ simple module that implements the energy consumption of software processes or hardware devices over time. The main purpose of these models is to provide the power or current consumption for the current simulation time. Most often, energy consumers are included as submodules in the compound module of the hardware devices or software components.

INET provides only a few built-in energy consumer models:

To simulate power consumption in a wireless network, the energy consumer model type must be configured for the transceivers. The following example demonstrates how to configure the power consumption parameters for a transceiver energy consumer model:

*.host[*].wlan[*].radio.energyConsumer.typename = "StateBasedEpEnergyConsumer"
*.host[*].wlan[*].radio.energyConsumer.sleepPowerConsumption = 0.1mW
*.host[*].wlan[*].radio.energyConsumer.receiverIdlePowerConsumption = 2mW
*.host[*].wlan[*].radio.energyConsumer.receiverBusyPowerConsumption = 5mW
*.host[*].wlan[*].radio.energyConsumer.receiverReceivingPowerConsumption = 10mW
*.host[*].wlan[*].radio.energyConsumer.transmitterIdlePowerConsumption = 2mW
*.host[*].wlan[*].radio.energyConsumer. \
   transmitterTransmittingPowerConsumption = 100mW # continue previous line

Energy Generator Models

Energy generator models describe the energy generation of devices over time. For example, a solar panel produces energy based on time, the panel’s location on the globe, its orientation towards the sun, and the actual weather conditions. Energy generators connect to an energy storage that absorbs the generated energy.

In INET, an energy generator model is an OMNeT++ simple module that implements the energy generation of a hardware device using a physical phenomenon over time. The main purpose of these models is to provide the power or current generation for the current simulation time. Most often, energy generation models are included as submodules in network nodes.

INET provides only one trivial energy/power-based statistical energy generator model called AlternatingEpEnergyGenerator. The following example shows how to configure its power generation parameters:

*.host[*].energyGenerator.typename = "AlternatingEpEnergyGenerator"
*.host[*].energyGenerator.energySinkModule = "^.energyStorage" # module ref.
*.host[*].energyGenerator.powerGeneration = 1mW
*.host[*].energyGenerator.sleepInterval = exponential(10s) # random intervals
*.host[*].energyGenerator.generationInterval = exponential(10s)

Energy Storage Models

Electronic devices that are not connected to an external power source must contain some component to store energy. For example, a mobile phone contains an electrochemical battery that provides energy for its display, CPU, and communication devices. It might also absorb energy produced by a solar panel installed on its display or by a portable charger plugged into the wall socket.

In the INET Framework, an energy storage model is an OMNeT++ simple module that models the physical phenomena used to store energy produced by generators and provide energy for consumers. The main purpose of these models is to compute the amount of available energy or charge at the current simulation time. They maintain a set of connected energy consumers and energy generators, their respective total power consumption, and total power generation.

INET contains a few built-in energy storage models:

  • IdealEpEnergyStorage is an idealistic model with infinite energy capacity and infinite power flow.

  • SimpleEpEnergyStorage is a non-trivial model that integrates the difference between the total consumed power and the total generated power over time.

  • SimpleCcBattery is a more realistic charge/current-based battery model that uses a charge independent ideal voltage source and internal resistance.

The following example shows how to configure a simple energy storage model:

*.host[*].energyStorage.typename = "SimpleEpEnergyStorage"
*.host[*].energyStorage.nominalCapacity = 0.05J # maximum capacity
*.host[*].energyStorage.initialCapacity = uniform(0J, nominalCapacity)

Energy Management Models

SimpleEpEnergyManagement

*.host[*].energyManagement.typename = "SimpleEpEnergyManagement"
*.host[*].energyManagement.nodeStartCapacity = 0.025J # start threshold
*.host[*].energyManagement.nodeShutdownCapacity = 0J # shutdown threshold

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