A) Key Chapter 7 Concept: Dividing up the communications channel into meaningful differences in order to allow maximum efficiency.

1) This would include the need to overcome noise, weak signals, or interference by using either:

a. repetition/ redundancy,

b. error correction coding,

c. more filters and more processing;

2) while still maintaining the greatest possible speed in interpretation (shortest bursts possible).

B) In order to accomplish this, simple frequency shift keying can be replaced by new forms of wireless transmission protocols:

"1) Frequency Division Multiple Access (FDMA) for cell phones or Dense Wave Division Multiplexing (DWDM) for optical fiber use different EM frequencies to separate out signals.

2) Time Division Multiple Access (TDMA) for cell phones and UltraWideBand (UWB) Pulse modulation both rely on the precise timing of signals to transmit data.

a. The European Global System for Mobile Communications (GSM) is an efficient hybrid FDMA/TDMA system.

3) Code Division Multiple Access (CDMA) for cell phones and military frequency hopping both use unique identifier codes to retrieve and order signals spread across a spectrum.

4) Orthogonal frequency division multiplexing (OFDM) for cell phones, digital radio/ television, and wireless internet (802.x). “Numerous signals are combined and transmitted over a single communications line or channel. Each signal is assigned a different frequency (subchannel) within the main channel and transmitted out of phase with other signals. The spacing between the subchannels is equal to the speed (bit rate) of the message, and the signals overlap. Spacing out the wave signals using OFDM allows only one signal to be "on" at a time (transmitting a value of 1) and ensures that all other signals are "off" (transmitting a value of 0). The active signal can then clearly be read.” ~ UT IT dept.

C) Please read the pdf primer on UWB below. If you want to see the UWB radar device that sees through walls (and you can bet the unit shown here is much bigger than the Black Op Special), then visit the Time Domain Corp. link below.