Internetworking (on which the Internet is based) consists in understanding that information is independent of the medium that carries it, and can be represented in a universal digital representation – the bit. What the Internet has taught us is that we need not design communications systems for voice bits that differ fundamentally from systems for video bits – instead, by carrying all kinds of traffic over whatever links are available, we can achieve a high degree of efficiency, both technically and economically. Interoperation between networks removes unnecessary transaction costs, enabling new applications to reach economically viable scale without the overhead of purpose-built networks for each new application, and enabling existing applications to be improved in an upward compatible way while allowing legacy versions to coexist.Link Discuss (via Werblog)
Digital signal processing is the use of extremely inexpensive and rapidly improving digital technology to handle all aspects of processing signals, including tuning, modulation, coding, and compression, among other functions. Since digital technology enables complex and adaptive algorithms we are able to approach closer and closer to the theoretical limits involved in manipulating and perceiving aspects of the physical world – in the case of radio, directly manipulating and sensing the electromagnetic fields that can be manipulated to carry information. The result has been a dramatic reduction in costs to implement efficient and adaptive techniques such as CDMA, spread spectrum, ultra-wideband radio, agile radio, power management, etc. At the limit, radio technology approaches the point where each radio is a “Cognitive Radio” that can sense its electromagnetic environment directly and modulate electromagnetic fields directly in time and amplitude.