Energy Management | Power Management in Mobile and Wireless

This article on energy management vs power management describes energy management and power management basics and techniques used in mobile and wireless networks.

It is desired to extend the life of wireless node where in it is not possible either to replace the battery or recharge the battery. This is becoming necessity in todays growing IoT based wireless networks and Ad hoc wireless networks. Most of these wireless nodes are designed as mesh nodes where in they directly communicate with each other through other nodes as relay or route nodes. There is no central co-ordinator or base station involved. Hence it is very important to extend life of the wireless nodes as its failure leads to breaks in the routing.

Energy Management

The energy management is done by management of following energy resources:
• Limiting battery discharge
• Transmit power adjustment
• Proper scheduling of power management as desired to save energy usage.

Above factors will increase life of a wireless node or mobile to a great extent. Let us understand these as well as other reasons of energy management in mobile and wireless networks.

➨It is difficult to recharge or replace battery during warfields or on journey.
➨Due to mesh topology, nodes will have more complex functionalities including routing and hence battery drains faster. This is observed in ad hoc wireless networks and not in infrastructure type of networks having base station in place.
➨Larger the battery size, larger its capacity to serve power. But increasing demand of small size mobile phones led to development of smaller size battery. This requires constraint on conserving battery power as much as possible while limiting its size too.
➨High transmit power consume more battery. Moreover higher transmission power led to interference from nearby station channels and this limits the overall capacity of simultaneous channel transmissions. Hence it is recommended to use optimum power during transmissions.
➨Moreover optimum power during transmission will help utilize the concept of frequency re-use. Hence same frequency can be re-used in nearby cells for transmission and reception. Open loop power control and closed loop power control algorithms will help in this regard. Refer Open Loop vs Closed Loop Power Control basics.

Power Management

gsm mobile phone block diagram

Fig-1:Mobile phone internal hardware block diagram

The figure-1 depicts typical hardware components in a GSM/CDMA/LTE mobile phone. As shown, it consists of memory (RAM/ROM), display, keypad, CPU running applications, DSP running wireless protocol stack, ADC/DAC, RF chip, Antenna, battery, SIM, mic, speaker, camera etc.

• The power management deals with minimizing the utilization of power by wireless system or mobile hardware components such as CPU, RAM, ROM, Display (LCD) etc.
• The other way is to incorporate low power consumption strategies in the protocol stack used by mobile or wireless system. The same is being analyzed and taken care while coding the protocol stack of wireless system.

Steps to increase Smartphone Battery Life

Following steps can be used in order to increase the smartphone battery life:
• Keep the device with battery in cool environment. This means do not expose the device in very high temperature environment.
• Turn off the GPS based location tracking.
• Do not charge the battery fully.
• Keep the brightness level as required during indoor and outdoor use, or keep optimum level.
• Schedule the update of applications over wifi connection.
• Keep WiFi and Bluetooth OFF when not in use.
• When you are in place where no network is available, keep the smartphone in flight mode.

RF and Wireless Terminologies