2. Outline • Previous Technologies -1G, 2G, 3G (CDMA, GSM, UMTS) – Multiplexing; Frequency, Time & Code • Reasons for New Research • How 4G Works - Architecture, AdHoc, IP core, OFDM • Impact of 4G - economic, socio-cultural, political
4. Previous Technology - 1G “First Generation” • Analog - Continuous in amplitude and time - Variations in the signal - disrupts over long distances • Simplest type to wireless data • Average between 4,800 to 9,600 bps (bits per second)
6. Previous Technology - 2G • Advantages - Digital - consists of 1s and 0s • Digital signal: 1) Low level, 2) High level, 3) Rising edge, and 4) Falling edge
7. Previous Technology - 2G - Allows for lower powered radio signals that require less battery power - CODEC introduction - program that encodes and decodes digital data stream or signal • Translates data from digital to analog and vice versa speaker voice CODEC 10111001
8. Previous Technology - 2G • Advantages - The digital voice encoding allows digital error checking • increase sound quality • lowers the noise level - Going all-digital allowed for the introduction of digital data transfer • SMS - “short message service” • E-mail
10. Previous Technology - 3G • CDMA - Code Division Multiple Access - Form of multiplexing - Does not divide up the channel by time or frequency - Encodes data with a special code associated with each channel
11. Types of Multiplexing • FDMA - Each phone call is allocated one frequency for the entire duration of the call. • TDMA - Each phone call is allocated a spot in the frequency for a small amount of time, and "takes turns" being transmitted. • CDMA - Each phone call is uniquely encoded and transmitted across the entire spectrum, in a manner known as spread spectrum transmission.
13. Reasons for New Research • Government are forced to support to the financially troubled operators • 3G phones are expensive • Lack of 2G mobile user buy-in for 3G wireless service • Lack of coverage because it is still a new service - i.e. Champaign-Urbana uses 2.5G - Chicago is 3G equipped
15. What is 4G? • Fourth Generation Technology • Faster and more reliable -100 Mb/s (802.11g wireless = 54Mb/s, 3G = 2Mb/s) • Lower cost than previous generations • Multi-standard wireless system - Bluetooth, Wired, Wireless (802.11x) • Ad Hoc Networking • IPv6 Core • OFDM used instead of CDMA • Potentially IEEE standard 802.11n - Most information is proprietary
16. Communications Architecture • Broadcast layer : fix access points, (ie cell tower) connected by fiber, microwave, or satellite (ISP) • Ad-hoc/hot-spot layer: wireless LANs (ie. internet at Starbuck’s) • Personal Layer Gateway: devices that connect to upper layers; cell phone, fax, voice, data modem, MP3 players, PDAs • Info-Sensor layer: environmental sensors • Fiber-optic wire layer : high speed subterranean labyrinth of fiber optic cables and repeaters
17. Ad Hoc Networks • Spontaneous self organization of networks of devices • Not necessarily connected to internet • 4G will create hybrid wireless networks using Ad Hoc networks • Form of mesh networking - Very reliable
18. When? • China Mobile, KPN, NTT DoCoMo, Orange, Intel, Motorola, Sprint Nextel, T-Mobile and Vodafone already doing research on 4G • Much of this information is proprietary at this time • Expected release of 4G services as early as 2008. • Majority of companies expect widespread use of 4G systems by 2010. • Lifecycle of 4G is estimated to be 15 years.
