The document discusses spectrum and wireless connectivity issues, particularly in developing parts of the world. It begins by describing a poor phone call between the author and a contact in Kenya due to spectrum interference. It then provides background on how radio spectrum works and how wireless networks operate using different frequencies. A key point is that limited and unstable network connectivity in remote areas is a major issue for developing regions in Africa, Asia, and the Americas. Expanding affordable access to remote communities is an important goal for creating a truly connected global village.
2. After several rings, John picks up my call
on his cellphone. I’ve called from Kenya
to ask his opinion. But the connection
keeps cutting out, and what I can hear is
almost unintelligible. I must sound just as
bad, because he asks me to dial him back
on his landline. This time, his voice is
much clearer. And he immediately
confirms what now seems glaringly
obvious: Despite their ubiquity and
decades-long existence, cellphones still
make for pretty poor phones.
But How can that be?
3. Today’s smartphones are incredible feats of engineering. Packing the processing power of a mid-1980s supercomputer
into a sleek, pocket-size slab, they can take photographs, play music and videos, and stream tens of megabits of data to
the palm of your hand every second. But try calling your boss in rush-hour traffic to say you’re running late, and
there’s a good chance your message won’t get through.
4. All wireless communications signals travel over the air via radio frequency, aka spectrum.
all use invisible airwaves (SPECTRUM) to transmit bits of data through the air
The TV broadcast you watch the radio program you listen to
the GPS
device that
helps get
you where
you're going
and the wireless phone
service you use to make
phone calls and check
Facebook from your
smartphone
5. The easiest way to understand what spectrum really is and how
it provides services is to look at your radio
When you tune your radio to 93.5 FM, you are tuning into a station that is
broadcasting at 93.5 megahertz. If you want to a listen to a different station, like
one that only plays country music or jazz, you turn the dial to another frequency
like 104.7 FM. And a different radio station will be transmitting over that
particular frequency on a different setting on your radio dial. No two stations
transmit over the same spectrum at the same time in the same area, because if
they did, they'd cause interference with one another.
6. Mobile phones work much the same way. Wireless operators,
cannot transmit wireless signals over the same frequencies in
the same markets at the same time.
Lets us look at this phenomena closely
7. A key part of any mobile phone specification is its operating frequency bands.
The supported frequency bands determine whether a certain handset is
compatible with a certain network carrier.
Your mobile phone, which receive their signals from towers,
are often referred to as cell phones. A cell is typically the area
(several miles) around a tower in which a signal can be
received.
8. GSM frequency bands or frequency ranges are the cellular
frequencies designated by the International Telecommunications
Union for the operation of GSM mobile phones.
You often see these details when you buy any mobile phone
9. Although there are many frequency bands, the radio frequency spectrum ranges from very low
frequency radio waves at around 10kHz (30 kilometres wavelength) up to 100GHz (3 millimetres
wavelength). The radio spectrum is divided into frequency bands reserved for a single use
or a range of compatible uses. Within each band, individual transmitters often use separate
frequencies, or channels, so they do not interfere with each other.
GSM-900 and GSM-1800 are used in most parts of the world: Europe, Middle East, Africa,
Australia, Oceania (and most of Asia).
In South and Central America the following countries use the following:
Bolivia – GSM-850 and 1900
Paraguay – GSM-850 and 1900
Peru – GSM-1900
Costa Rica – GSM-1800
Brazil – GSM-850, 900, 1800 and 1900
Guatemala – GSM-850, GSM-900 and 1900
El Salvador – GSM-850, GSM-900 and 1900
Venezuela – GSM-850, GSM-900 and 1900
GSM-900 and GSM-1800
10. Today, most telephones support multiple bands as used in different countries to facilitate roaming. These
are typically referred to as multi-band phones. Dual-band phones can cover GSM networks in pairs such
as 900 and 1800 MHz frequencies (Europe, Asia, Australia and Brazil) or 850 and 1900 (North America
and Brazil). European tri-band phones typically cover the 900, 1800 and 1900 bands giving good
coverage in Europe and allowing limited use in North America, while North American tri-band phones
utilize 850, 1800 and 1900 for widespread North American service but limited worldwide use. A new
addition has been the quad-band phone, also known as a World Phone, supporting at least all four major
GSM bands, allowing for global use (excluding non-GSM countries such as Japan or South Korea).
With millions of phones serving most of us. We often take
our ability to connect for granted. Whereas there are a
large number of us living in developing countries who still
need to travel a mile to make a call.
11. East African Community (EAC) figures suggest 90 percent of
schools and 30 percent of hospitals in the region are off-grid,
while only 24 percent of the developing world is connected to the
internet.
While South Africa and a few other African countries have mobile phone networks that reach
around 80% of the population, other countries have 10% coverage and less. High speed
broadband networking is often available in the major cities and some other areas. For the rest,
network coverage is through the mobile phone network which is 2G, or EDGE (2.5G) at best.
What do these terms imply?
If you can remember the days of dial-up 9600 baud modems, that's about
what you can expect on these networks. To put it another way if you're too
young to remember the 'good old days’, Broadband is defined as better
than 1 Mbit/sec , while 2G is about 1/100th of that.
The presentation is based on the African context, but it is felt that it is equally applicable to other developing regions in Asia and the
Americas
12. Network connectivity is slow, unstable and often non-
existent in the remote areas of the developing world.
The Major Reason Why Some of Us Are Left Out
Costs of network connectivity are high
Number of People in a remote area are often not enough for Telecom
Companies to make profits out of.
Other Minor Reasons
13. How can we create a world where everyone is connected?
What steps should we take to include our brothers in the remotest areas in our “global
village”?