Australian Government About Mobile Phone neworks Fact Sheet EME Series 6

Fact Sheet

EME Committee on ElecPtruobmlica gHneeatlitchEIsnseurgeys  Series

No. 6

About mobile phone networks

How does a mobile phone network operate?

A mobile phone network consists of a system of adjoining zones called cells'. Cells vary in size with the radius generally between 2 and 10 kilometres. Each cell has its own base station which sends and receives radio signals throughout its specified zone. Base stations produce very weak radiofrequency (RF) electromagnetic energy (EME) exposure levels.

For information on potential health effects see fact sheet 1

 Electromagnetic energy and its effects'.

Mobile phone base stations must be carefully located in relation to each other, so each cell in the network functions efficiently to ensure minimum network congestion and good signal quality.

When a call is made in Australia from a mobile phone, the network allocates the call to an available RF channel (or carrier frequency) within each cell. Unless the call is to  another  mobile  phone  within  the  same  cell,  the  call  is  then  "switched"  to  a conventional phone line. If the mobile phone user is travelling, the network will pass the call on to the base station that can provide the best available signal. Multiple cells are required because of the finite nature of the number of calls each base station can accommodate at any given point in time.

There are a number of networks that operate in Australia. The Global System for Mobile communication (GSM), which operates in the 900 and 1800 MHz band, the Code Division Multiple Access (CDMA) network, which operates in the 800 MHz band, the Universal Mobile Telecommunications System (UMTS) also known as 3G, which  operates  in  the  2100  MHz  band  and  Bluetooth,  which  operates  in  the 2400 MHz band.

Mobile phone antennas need to be mounted clear of surrounding obstructions like trees and buildings, to reduce dead spots' in coverage and allow the mobile phone base station to cover its intended cells with a minimum of transmitter power. They must also be sited where they will not interfere with neighbouring cells.

The more base stations of a particular carrier there are in an area, the smaller the cells, which means the power and energy levels of each are lower.

In areas of high mobile phone use, where there are many small cells to meet traffic

demands, antennas do not need to be very high and can be installed on building  Y6A1L9LLAoMwBeIrEP leVnItCy R3o0a8d5 roofs or small poles. These antenna configurations are called low impact facilities.  Phone +613 9433 2211

In low usage areas, however, the cells are larger and the antennas are mounted on  Fax +613 9432 1835 taller masts and towers.  E-mail: info@arpansa.gov.au

Web: www.arpansa.gov.au Freecall: 1800 022 333

(a free call from fixed phones in Australia)

In an area of increasing mobile phone use the number of cells needed to maintain  Fact seevrevni cien qaureaalist ywihnecrree amseosb. iOleftneent wthoirsk mcoevaenrsagane aadditionallready exi sbasets. I fstation(s)this is notisdneedone ted,he Sheet

mobile network will not operate properly and, as a result, mobile phone users may

not be able to connect to their network (congestion).  EME

Series What are the RF EME levels from mobile phone antennas?  No. 6

Base  stations  transmit  power  levels  from  a  few  watts  to  100  watts  or  more, depending on the size of the region or "cell" that they are designed to service. Base station antennas are typically about 20-30 cm in width and one to two metres in length, mounted on buildings or towers at a height of from 15 to 50 metres above ground. These antennas emit RF beams that are typically very narrow in the vertical direction but quite broad in the horizontal direction. Because of the narrow vertical spread of the beam, the RF field intensity at the ground directly below the antenna is low. The RF field intensity increases slightly up to distances of several hundred metres (the analogy of a water sprinkler is often used to describe the beam from a base station).

Rooftop  antennas  have  restricted  access  in  order  to  keep  the  public  away  from locations where the RF fields may exceed exposure limits. Since antennas direct their power outward, and do not radiate significant amounts of energy from their back surfaces or towards the top or bottom of the antenna, the levels of RF energy inside or to the sides of the building are normally very low.

ARPANSA conducted measurements of RF EME  levels at 14 locations near GSM mobile phone  base stations during 1997-99. ARPANSA found  that emissions from these antennas were usually  many orders of magnitude below the limit of 450  W/cm2  set  by  the  ARPANSA  Radiation  Protection Standard "Maximum Exposure Levels  to Radiofrequency Fields – 3 kHz to 300 GHz"  for  general  public  exposure. The  levels  measured were comparable to television and FM  radio transmitters and considerably lower than  those from AM radio transmitters, all measured  at  the  same  time. A  comparison  of  RF  EME  levels between a mobile base station and other  sources of RF EME at Highbury Park, Burwood,  Victoria is shown in Figure 1.  

A  further  study  of  60  base  stations,  including  CDMA,  GSM  and  3G  technologies,  in  2003  confirmed that RF EME levels were well below  general public exposure limits.

For further information see fact sheet 4 The ARPANSA RF exposure standard'.

Are mobile phone base stations a health risk?

The  weight  of  national  and  international  scientific  opinion  is  that  there  is  no substantiated  evidence  that  living  near  a  mobile  phone  antenna  causes  adverse health effects.

For further information see fact sheet 1 Electromagnetic energy and its effects'.

Typical RF EME Power Density Levels Fact GSM base  UH1F%TV VH1F%TV Paging Sheet station 0.2 %

1%

EME FM5r%adio Series

No. 6

AM radio 92%

Figure 1.  The pie chart shows a typical example of the relationship of the GSM system with other broadcasters

using radio frequency transmission. Television and FM radio use frequencies of about 100MHz and AM radio uses frequencies near 1MHz. The pie chart gives the relative amount of RF EME emitted by various sources measured 0.1km from a typical base station. Measurements of power density levels (in microwatts per square centimetre) are made at a position which maximises the exposure from the mobile phone base station. It can be seen that exposure levels are less than those from FM radio stations  and  significantly  less  than  levels  from  AM  radio  stations  (measurements  were  taken  at Highbury Park, Burwood, Victoria).

What are the current arrangements in relation to siting of mobile phone base stations?

Regulations to protect the public from RF EME exposure from telecommunications facilities  established  by  the  Australian  Communications  and  Media  Authority (ACMA) do not set any distance requirements between the facility and other land uses such as residences, schools or hospitals.

Similarly, the ACIF Code (see below) does not specify arbitrary distances at which infrastructure must be sited from community sensitive locations, because arbitrary distances do not necessarily reflect a precautionary approach. In fact, infrastructure sited further from a community sensitive area may need to operate at a higher power and may result in higher EME exposures in that sensitive area. Furthermore, it must be remembered that evidence gathered by ARPANSA suggests that exposure levels in public areas are so far below the exposure limit set by ACMA, that EME emissions from mobile phone base stations have no implications for health.

Telecommunications carriers' responsibilities relating to siting of base stations and consultation are set out in the Telecommunications Act 1997 and its subordinate legislation, The Telecommunications (Low Impact Facilities) Determination 1997 (amended 1999) and the Telecommunications Code of Practice 1997.

Carriers  have  the  right  to  install  low-impact  facilities  under  conditions  that  are outlined in the publication Accessing and Installing Telecommunications facilities - a  Guide.  This  publication  is  available  from  any  ACMA  office,  and  may  also  be downloaded via the ACMA website at:

http://www.acma.gov.au/ACMAINTER:STANDARD::pc=PC_569

Facilities that are not low-impact fall under the jurisdiction of state planning laws.  Fact The  Act  recognises  the  trade  off  between  encouraging  the  construction  of  Sheet telecommunications  networks  for  the  benefit  of  consumers  and  the  broader

economy,  and  accommodating  aesthetic  and  environmental  concerns  of  the  EME community.  Series

No. 6

The ACIF Code

In addition to State and Federal regulations there is an ACMA registered industry code established by the Australian Communications Industry Forum (ACIF) called Industry  Code  for  the  Deployment  of  Mobile  Phone  Network  C564  (the  "ACIF Code").

The  Code  supplements  the  requirements  already  imposed  on  carriers  under  the existing legislative scheme by requiring them to better inform and consult with the local community and to adopt a precautionary approach in planning, installing and operating telecommunications infrastructure. The ACIF Code is also available from the ACMA website at:

http://emr.acma.gov.au

With carriers subject to State and Territory planning laws and the ACIF Code, the local community and council are  able to  provide input into telecommunications network roll out.

 (Revised: March 2006)

Fact sheets in the EME series are:

Fact sheet 1:  Electromagnetic energy and its effects

Fact sheet 2:  Government action on electromagnetic energy public health

issues

Fact sheet 3:  Australian research into EME

Fact sheet 4:  The ARPANSA RF Exposure Standard

Fact sheet 5:  About mobile phones

Fact sheet 6:  About mobile phone networks

Fact sheet 7:  What about using a mobile phone while driving

Fact sheet 8:  Potential interference of mobile phones with pacemakers,

hearing aids and other devices

Fact sheet 9:  What about base stations and telecommunications towers - are

there any health effects?

Fact sheet 10:  What about broadcast towers - are there any health effects? Fact sheet 11:  Mobile phones and children

For further information you can visit the ARPANSA web site at:

http://www.arpansa.gov.au