Wireless Infrastructure: Overview and Issues H. Scott Matthews February 24, 2003

Homework #2  Average: 48/55

Midterm Exam  Handed out today, due Wed March 5

Recap of Last Lecture  Utils had become vertically integrated  Deregulation changed this structure  Partly to blame for transmission constraints  Now a hierarchical jurisdiction to manage  Despite 100 years of research and practice, overall system efficiency low

Source: Lawrence Berkeley Labs;

Early Radio/Wireless Events  More detail on other telephone/wireless:   Wireless by induction/conduction/radiation  Marconi: First ‘radio’ system created (1901)  Application: ships - intended wireless telegraph  1906: Radio band-wave comm. - speech  1910: Ericsson - first car ‘telephone’  1924: First mobile car ‘radio’ telephone  1927: US Federal Radio Commission started  1934: Federal Communications Commission  Telephone & radio under jurisdiction - licenses for spectrum  Early history - very/too close to industry to manage

More Wireless Events  1958: Invention of integrated circuit (IC)  In this era, FCC ‘lazy’ in giving spectrum  1973: First handheld cell phone in US  Originally analog (handout) now digital  Analog in 800 MHz range, Dig 800/1900  ‘Cellular’ networks - freq reuse and handoff  Freq reuse allows more use of spectrum, manages potential ‘interference’  Handoff trades ownership of signal to other cells  Antennas associated with cells  Cell size can be 1-50km radius - digital 10km  Some cells have hierarchy of smaller cells  Base station manages freq and power of handsets

AT&T Breakup Effects  Originally AT&T monopoly on telephone service in US, broken up in 1980s  Created ‘baby bells’ - RBOCs  Intended to compete w/ each other  1990s - started merging  Now provide wireless service in competition (e.g. Cingular = Bell South, Verizon = Bell Atlantic + NE bells, etc)

Antenna/Cell Locations  Generally want to have 90% of an area ‘covered’ and ‘usable’ 90% of time  Includes base station/equip and antenna  Siting depends on demographics, population, growth, road usage, future trends  Don’t want too abandon cells, so choose now and add capacity/split cells later  Height of antenna effects range of cell  Consider absorption of natural environment (I.e. leaves on trees absorb some of signal!)  Need more power in summer than winter  Unlike rest of world, US was worried about backward compatibility when going A->D

System Statistics (mid 2002)  From CTIA Industry Surveys (US only)   135 million “subscribers” (all sectors)  Still rapid growth, but slowing (50% penetration!)  Almost 90% digital  131,000 ‘cell sites’ (each using 3-5kW power)  About 500 billion wireless minutes used/yr  Avg call length 3 minutes  Number of wired ‘subscribers’ - about same  And decreasing as DSL, mobile phones happen  What are infrastructure management issues?

Wired and Wireless Users Source: ITU World Telecom Development Report, March 2002

Sample Wireless Telephone Coverage Map - What Is/Is Not Covered by this Manufacturer - and is this total US coverage?

Other Issues  Wireless not really wireless  High dependence on wired (PSTN) network  FCC - defined above - communications  Regulates activities, mergers of telecoms  State PUCs - also involved  Industry Groups  Big difference is less oversight of these companies now that monopoly effects lower