2. Clear and Present Danger After several rings, John picks up my call on his cellphone. Ive 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 conrms 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. Todays 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 youre running late, and theres a good chance your message wont get through.
4. What is Spectrum? 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 specication 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. Frequency Bands 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. A Disconnect East African Community (EAC) gures 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 dened 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. Important Note 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 prots out of. Awareness Other Minor Reasons
13. In Conclusion 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?