Mobiles and Health
Introduction
India has over 900 million mobile phone connections. The innumerable social and economic benefits of mobile telephony have made it integral to our lives. Mobile telephony relies upon an extensive network of base stations (popularly referred to as towers/sites), to transmit and receive information with Radio Frequency (RF) signals.
Mobile phones are mini transmitters that communicate with the base stations using RF signals. There are however, some concerns and even myths surrounding the effects of these signals on our health and wellbeing.
At Vi, the health and safety of our customers, employees, contractors and the public is of paramount importance. Our vision is to lead the industry in responding to public concerns about mobile phones, towers and health by demonstrating leading edge practices and encouraging others to follow.
At a worldwide level, we have a board dedicated to radiofrequency (RF) matters that includes representatives from our local markets and key functional areas. This board monitors public concerns, helps local markets to provide public information and advice, and reviews the available information about mobile phones, masts and health. The board also sets our strategy, policies and goals relating to mobile phones, towers and health.
We have based this section of our website on the findings of reputed health agencies like the World Health Organisation (WHO) and other independent expert groups from around the world. Our aim is to provide a range of useful information; answer the most commonly asked questions; and communicate the most up-to-date scientific opinion.
Mobile phones and their towers produce RF signals/Electromagnetic Fields (EMF); emissions within internationally laid down exposure limits to be protective of our health and wellbeing.
From a technology infrastructure point of view, for a mobile phone to work and communicate well:
- A network of base stations to connect customers' calls and deliver the data they need;
- Use Radio frequency (RF) fields to send and receive calls, texts, emails, pictures, web, TV and downloads; an RF signal is sent to the nearest base station (often called a mobile tower), which sends the signal to a digital exchange and on to the main telephone network or on to the internet. This connects the signal to the receiving phone, again via a base station (if it is another mobile phone) or a fixed line phone or the internet;
- Use the minimum transmit power needed to communicate with the base station. This automatically adjusts according to the signal at the base station. The better the signal – the lower the transmitted power needed from the mobile phone. The power needed depends on a range of factors, including:
- Distance between the mobile phone and the base station;
- Landscape and buildings between the mobile phone and the base station;
- Operating frequency band at a given time; and
- The service the mobile phone is being used for (e.g. texting, data or voice calls)
- Connects to the base station providing the best signal – usually the nearest one. As a person moves away from the base station the signal becomes weaker, so the mobile phone automatically adjusts its own transmit power to maintain the minimum needed to communicate with the base station.
The area covered by a base station is known as a "cell". Each cell is usually split into three sectors, which overlap with the sectors of neighbouring cells to create a seamless and uninterrupted mobile network. When people travel, the signal is passed from one base station to the next, and typically never has to travel further than the nearest base station.
The size and shape of each cell is determined by the features of the surrounding area, such as buildings, trees and hills, which can block signals.
- Cells are largest in flat open landscapes, where they can cover a radius of several kilometres.
- Cells in urban areas typically range between 200-500mts radius.
- The smallest cells, covering a radius of a few tens or hundreds of metres, are in built-up dense urban areas, where micro-cell base stations are used to provide extra coverage and capacity.
- Each base station can only handle a limited number of connections at a time.
- In areas of high demand, additional antennas are sometimes added to a base station to send and receive more calls and other mobile services, or an extra base station is installed.
- A large number of base stations are needed to allow more people to use mobile phones, from more locations, and for coverage to be continuous when moving around.