Wednesday, 5 December 2012

Health and safety


Health and safety
The Independent Expert Group on Mobile Phones (IEGMP) in the Stewart
Report (Stewart 2000) recommended further research be carried out into
possible effects of mobile phone use on health. The National Radiation
Protection Board’s (NRPB) independent Advisory Group on Non-Ionising
Radiation (AGNIR: Chairman, Professor Anthony Swerdlow) subsequently
examined recent (ie post-Stewart) experimental and epidemiological
evidence for adverse health effects caused by exposure to radiofrequency
(RF) transmissions, including those associated with mobile telephone
handsets and base stations.
AGNIR has concluded (AGNIR 2003) that there is no biological evidence
for mutation or tumour causation by RF exposure, and epidemiological
studies overall do not support causal associations between exposures
to RF and the risk of cancer, in particular from mobile phone use. AGNIR
found a number of studies that suggested possible effects on brain function
at RF exposure levels comparable with those from mobile phone handset
use. However, AGNIR regarded the overall evidence as inconclusive.
AGNIR did not state that mobile phones have been proven to be
entirely risk free. It identified the limitations of the published research
and concluded that: ‘In aggregate the research published since the
Stewart report (Stewart, 2000) does not give cause for concern.
The weight of evidence now available does not suggest that there are
adverse health effects from exposures to RF fields below guideline levels,
but the published research on RF exposures and health has limitations,
and mobile phones have only been in widespread use for a relatively
short time. The possibility therefore remains open that there could
be health effects from exposure to RF fields below guideline levels;
hence continued research is needed.’ For more information see
www.nrpb.org/advisory_groups/agnir/index.htm.
The NRPB have published a further report (NRPB, 2004) and a literature
review (Sienkiewicz and Kowalczuk, 2004) which brings together the
findings of 26 reports on mobile phones and health prepared by other
national and medical bodies including an Expert Panel of the Royal Society
of Canada (Royal Society of Canada 1999), the Department of Health
in France (Zmirou et al. 2001) and the Health Council of the Netherlands
(NCN, 2002) as well as the British Medical Association’s (BMA) interim
report (BMA 2001). NRPB found that the conclusions of these studies
are very similar to those of the Stewart and AGNIR reports in relation to
possible health effects from exposure to RF from both mobile phones
and base stations. The Health Council of the Netherlands (HCN) differed
a little from the others in that this was the only report that did not consider
it necessary to recommend a precautionary approach of limiting mobile
telephone use by children. HCN concluded that ‘there is no reason to
recommend that children should restrict the use of mobile telephones as
much as possible’. In contrast the original Stewart Report (Stewart, 2000)
stated that ‘if there are currently unrecognised adverse health effects
from the use of mobile phones, children may be more vulnerable,’ and
recommended that ‘the widespread use of mobile phones by children
for non-essential calls should be discouraged.’

Tuesday, 4 December 2012

Viruses



A computer virus, believed to be the first spread by mobile phones, has
recently been sent to anti-virus firms. No infections have been reported,
and this virus is harmless, but it is proof that mobile phones could be
at risk from virus writers. The virus, known as Cabir, infects phones and
devices running the Symbian operating system and can be passed to
other devices via Bluetooth. Requiring Bluetooth to travel significantly
restricts the threat posed by the worm as it is thereby constrained to
a radius of about 30 metres. Also, transfer is dependent upon a nearby
phone user having Bluetooth turned on and accepting the virus in spite
of it being preceded by a warning that the source of the file is unknown.
For now, the Windows operating system is still the primary target for
virus writers and they do not seem very interested in mobile devices.
Indeed, the first virus for a Palm device was detected in 2000 and
it has not, to date, resulted in a problem for PDA owners.

Inrastructure


Infrastructure
Sales of advanced handsets such as those described above and the development of value-added non-voice services are growing. Mobile network operators around the world are hoping to emulate the success
of operators in Japan and South Korea. Many network operators are launching third generation (3G) networks in 2004 and 2005, and these promise fast, broad bandwidth connections, enhanced multimedia and advanced services such as video conferencing. However, most observers
believe that full availability and mass adoption of 3G services will take a few more years.
Many companies are still experimenting with ways of making money from mobile data using the current GSM or 2G networks and the so-called 2.5G networks (2.5G is 2G with faster and more efficient data transmission resulting from transmitting messages in labelled ‘packets’, thus allowing
many users to share a single connection). 2.5G networks are enabling subscribers to access a wide selection of new non-voice services and operators hope that consumer familiarity
built now will lead to 3G mass adoption later. Meanwhile, the performance of 2.5G networks will be improved by the new EDGE technology. EDGE (Enhanced Data Rates for GSM Evolution) is a technology that increases capacity, improves quality and allows use of advanced services over the
existing GSM network. EDGE is an upgrade of the GPRS (General Packet Radio Services) system for data transfer in GSM networks. The Norwegian telecommunications company Telnor claim (Johnsen 2004) that the EDGE data transfer rate is substantially faster than possible speeds using
GPRS technology and can reach between 100 and 200 kbit/s under perfect circumstances. EDGE implementation does, however, require upgrades to both base stations and mobile phones.

Mobile phones technology Update


Mobile phones
There are estimated to be 1.5 billion mobile phones in the world today(Prensky, 2004). This is more than three times the number of personal computers (PCs), and today’s most sophisticated phones have the processing powe of a mid-1990s PC. These facts, and the range of computer-like functionality offered by top-of-the-range devices, are leading some observers to speculate that many people in the not so distant future will start to see the mobile phone as an alternative to a PC. For example Jeff Hawkins, inventor of the
Palm Pilot, was recently quoted (Stone 2004) as saying, ‘One day, 2 or 3 billion people will have cell phones, and they are not all going to have PCs … The mobile phone will become their digital life’. Sean Maloney, an executive vice-president at Intel (also interviewed by Stone) disagrees,
on the grounds that, ‘Hundreds of millions of people are not going toreplace the full screen, mouse and keyboard experience with staring at a little screen’. Clearly, neither view is likely to be completely objective,
but the fact that the debate is happening is an indication of how powerful and sophisticated mobile devices are becoming. In the m-learning project we chose to

Thursday, 19 July 2012


Mobile phone operators


Global mobile phone subscribers per country from 1980-2009. The growth in users has been exponential since they were first made available.
The world's largest individual mobile operator by subscribers is China Mobile with over 500 million mobile phone subscribers.Over 50 mobile operators have over 10 million subscribers each, and over 150 mobile operators had at least one million subscribers by the end of 2009. In February 2010, there were 5.6 billion mobile phone subscribers, a number that is expected to grow.

Manufacturers

Quantity Market Shares by Gartner
(New Sales)
BRANDPercent
Nokia 2010
  
28.9%
Nokia 2011
  
23.8%
Samsung 2010
  
17.6%
Samsung 2011
  
17.7%
Apple 2010
  
2.9%
Apple 2011
  
5.0%
LG Electronics 2010
  
7.1%
LG Electronics 2011
  
4.9%
ZTE 2010
  
1.9%
ZTE 2011
  
3.2%
Others-1 2010
  
30.4%
Others-1 2011
  
33.7%
Note: Others-1 consist of Sony Ericsson, Motorola, ZTE, HTC and Huawei.(2009-2010)
Prior to 2010, Nokia was the market leader.

Features


All mobile phones have a number of features in common, but manufacturers also try to differentiate their own products by implementing additional functions to make them more attractive to consumers. This has led to great innovation in mobile phone development over the past 20 years.
The common components found on all phones are:

Wednesday, 11 July 2012

Land Mobile or IMTS


Learn the present by looking at the past. Here's some great reading on the transition from mobile telephone service to cellular. It outlines the IMTS system that influenced tone signaling in AMPS, and gives some clear diagrams outlining AMPS' structure. This is from the long out of print A History of Engineering and Science in the Bell System: Communications Sciences (1925 -- 1980), prepared by members of the technical staff, AT&T Bell Laboratories, c. 1984, p.518 et. seq.:

More on IMTS! (1) Service cost and per-minute charges table / (2) Product literature photos / (3) Briefcase Model Phone / (4) More info on the briefcase model / (5) MTS and IMTS history / (6) Bell System (7) Outline of IMTS / (8) Land Mobile Page 1 (375K) / (9) Land Mobile Page Two (375K) / (10) The Canyon GCS Briefcase Telephone
A History of Engineering and Science in the Bell System: Communications Sciences (1925 -- 1980)
Channel Availability

Tuesday, 10 July 2012

AMPS Call Processing



This is AMPS call processing for analog and digital services, CDMA or IS-95 excluded. There are two parts to this diagram, click on the links below to see the readable images. I've split the diagram in this way to make it quicker to download. If you want to see the whole graphic at once then click here.