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- Not considering cordless phones, CB radios, pagers, car phones etc.
- Iridium: catastrophes (Haiti), hard to reach places: expeditions, Arctic …
- ATT Terrestar hybrid cell & satellite switches to satellite when out of range, covers US, looks like Blackberry, not cheap $799 + $5/month on top of regular voice & data. Calls are $0.65/min. See http://www.pcworld.com/article/172944/terrestar_satellite_phone_coming_to_atandt.html
- Laptops, netbooks (OLPC), smartbooks (kindle,iPADs), Cell phone and smartphones
Cell phones
- History (see http://electronics.howstuffworks.com/cell-phone4.htm)
- 2G, 3G (GSM, CDMA), WiMAX, LTE,
- How cell phones work (see presentation )
- Towers: cost $120-500K, 9mos to 3 years (incl permits & construction), 80’-400’, 20 people
- Sectors, frequencies (why low is good: potentially 2-3 times more cell towers for same coverage), channels, initial connection, hand-offs, tower radius <=10m in flat areas, often want less (e.g. by reducing power) in cities.
- Importance, growth
- Mobile telecommunications connections worldwide reached five billion in the first week of July on growth in India and China, and could triple by 2016, PRTM Management Consultants said. Revenue will “probably grow 20 percent to 30 percent in the same time,” Ameet Shah, a consultant for PRTM, said from London in a telephone interview. The current revenue figure is about US$900 billion, according to researcher The Mobile World.
Operators must change their operating models and may need to merge to survive, Shah said. Instead of concentrating on “high value, high price and low volume” they must focus on “immense scale, low value and low prices,” he said. Some markets have grown to 150%-200% penetration relative to their populations. More penetration than Internet.
- Mobile telecommunications connections worldwide reached five billion in the first week of July on growth in India and China, and could triple by 2016, PRTM Management Consultants said. Revenue will “probably grow 20 percent to 30 percent in the same time,” Ameet Shah, a consultant for PRTM, said from London in a telephone interview. The current revenue figure is about US$900 billion, according to researcher The Mobile World.
- See presentation
- How they work
- History
- Cell phone components
- Power
- Carriers
- Coverage
- Bars
- Growth
- Concerns
- Power:
- Many manufactures have agreed on standard (micro-USB) for charging phones. So do not need a charger with each phone.
- November 2008 the top five mobile phone manufacturers Nokia, Samsung, LG Electronics, Sony Ericsson and Motorola set up a star rating system to rate the efficiency of their chargers in the no-load condition.
- Formerly, the most common form of mobile phone batteries were nickel metal-hydride, as they have a low size and weight. lithium ion batteries are sometimes used, as they are lighter and do not have the voltage depression that nickel metal-hydride batteries do. Many mobile phone manufacturers have now switched to using lithium-polymer batteries as opposed to the older Lithium-Ion, the main advantages of this being even lower weight and the possibility to make the battery a shape other than strict cuboid.17 Mobile phone manufacturers have been experimenting with alternative power sources, including solar cells.
- Big demand for increased bandwidth for newer services (see below) however 4G upgrade is very expensive only by companies like Verizon and AT&T can afford and could drain money for wireless build-out from standard services (e.g. wired). In US this could lead to a duopoly since T-Mobile and Sprint may not be able to compete.
Smartphones
(see http://en.wikipedia.org/wiki/Smartphone)
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