Mesh Telephony

http://www.youtube.com/watch?v=Z3p2BYFXBkU&list=UUD7iJhnqGVKyjoXavxJrFRA&index=9&feature=plcp

http://www.youtube.com/watch?v=K819ggBvkU0&feature=related

• Complementary to Towers and Satellites
• 2.4Ghz
• 868 MhZ
• FCC and
• licensing is national
• ISM 915 MhZ - available in enough countries
• WiFi was illegal in many countries before large user base
• $1/4M for a single tower in africa - defending tower and diesel generator
• Key: vast majority of calls are in local areas
• Store and forward - Serval rhizome
• Single house for WiFi
• For 10 house range - 1% of people need to be on
• 10kb codec 2 1400 bps for clear voice - CODEC2, 175bytes per second with no interframe compression
• 915MHz 100kbit = +19db versus 2.4GHz wifi @1mbit
• ~9db is from band propagation differences
• +10db from 10x lower bit rate = 10x more energy per bit
• 6.02db = 2x range. 19 ~= 2x2x2 = 8x range
• "a few hundred metres" in urban/indoors
• "one to a few km" in clear line of site/outdoors

Cost

• $100-300 cost (small vs. tablet)
• $100k - custom phone from a phone pro

Design

• CPU - 600 MHz
• Touch screen

Applications

• GSM, 3G
• CDMA
• Mesh phone - medical diagnostic. Remote hospital.
  • Open MRS
  • pulse-oxy - $1-10 - pulse rate and oxygenation
  • bloodpressure cuff < $100 - blood pressure - difference between difference between systolic and diastolic via doppler ultrasound, can get difference, but not absolute
  • imaging ultrasound = ? <$500 - natal care, etc.
  • on the open market now, cheap imaging ultrasound is $4k
  • $10 - $50k for hospital-style units
  • phone + pulseoxy + imaging ultrasound = ~$500 at low end, <$1k at high-end

Political

• Prior to Industrial Revolution, corporations could not produce better than a cottage - but could do it more times (without economy of scale)
• Now, in a back yard, one can do what a multi-billion dollar industry can do
• For a brief time in global history, where advantage of economy of scale clearly outweighed the disadvantages
  • We give up a bit of sovereignty for a reduced cost of goods
• Peak of modernist movement/attitude 1960 - value of centralization/economy of scale vs individual effort

Phones

• Huawei IDEOS X1
• Samsung Galaxy Tab
• Can root - android and