Replacing COPPER conductors with NANOTUBES

The life of the silicon chip industry

components to silicon chips to increase computer capability. Because copper’s
resistance to electricity increases greatly as the metal’s dimensions decreases there is a limit to how small copper conductors can be.
In contrast, extremely tiny carbon nanotubes can substitute for copper conductors in smaller computer chip electronic configurations because carbon nanotube electrical resistance is not high.
The new process includes ‘growing’ microscopic, whisker-like carbon nanotubes on the surface of a silicon wafer by means of a chemical process. Researchers deposit a layer of silica over the nanotubes grown on the chip to fill the spaces between the tubes. Then the surface is polished flat.Scientists can build more multiple, cake-like layers with vertical carbon nanotube ‘wires’ that can interconnect layers of electronics that made up the chip

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Introduction to CDMA

Cellular networks are wireless WANs that establish a connections between cellular users. The cellular network is comprised of many "cells". The users communicate within a cell through wireless communications. A Base Transceiver Station (BTS) is used by the mobile units in each cell by using wireless communications. One BTS is assigned to each cell. Regular cable communication channels can be used to connect the BTSs to the Mobile Switching Center (MSC). The MSC determines the destination of the call received from a BTS and routes it to a proper destination either by sending it to another BTS or to a regular telephone network. Keep in mind that the communications is wireless within a cell only.
The words "code" and "division" are important parts of how CDMA works. CDMA uses codes to convert between analog voice signals and digital signals. CDMA also uses codes to separate (or divide) voice and control data into data streams called "channels." These digital data stream channels should not be confused with frequency channels.

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CODE DIVISION MULTIPLE ACCESS (CDMA)

The current cellular networks use many different, in compatible standards which relay on different frequency modulation techniques. The focus of the third generation wireless systems is on a predominantly analog because mobile communications have been primarily developed for voice users. How ever the use of cellular networks to support mobile communicating applications is increasing rapidly due to the emphasis on mobile commerce.

A collection of technologies are emerging to provide analog as well as digital services over cellular networks to support mobile users and applications. The cellular networks are evolving through first, second and third generations. The technology CDMA belongs to third generation of cellular networks.

This is an attempt to give you clear idea on “how to generate a CDMA signal” and “what are the stages involved to generate a CDMA signal”. It also includes “what are the call processing stages”.

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Worldwide Interoperability for Microwave Access(Wi-MAX)

The two driving forces of modern Internet are broadband, and wireless. The WiMax standard combines the two, delivering high-speed broadband Internet access over a wireless connection. The main problems with broadband access are that it is pretty expensive and it doesn't reach all areas. The main problem with WiFi access is that hot spots are very small, so coverage is sparse.

Wi-MAX is short for Worldwide Interoperability for Microwave Access, and it also goes by the IEEE name 802.16. WiMAX has the potential to do to broadband Internet access what cell phones have done to phone access. In the same way that many people have given up their "land lines" in favor of cell phones, WiMAX could replace cable and DSL services, providing universal Internet access just about anywhere you go. Wi-MAX delivers a point-to-multi point architecture, making it an ideal method for carriers to deliver broadband to locations where wired connections would be difficult or costly. It may also provide a useful solution for delivering broadband to rural areas where high-speed lines have not yet become available. A WiMax connection can also be bridged or routed to a standard wired or wireless Local Area Network (LAN).

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