Data is carried through networks by signals. A signal is transmitted over a physical medium according to some transmission technique(e. g., analog, digital, baseband, modulated, multiplexed, compressed, spread spectrum). Physical media include metallic cables, optical fibers, and the open air (chapter 7 in this week's reading is devoted to this topic). A transmission medium is characterized primarily by a raw bandwidth (in Hertz) and a level of "noise" that corrupts signal transmission. These 2 criteria determine basically the transmission speed in bits/sec. The speed keeps being enhanced by advanced transmission and signal processing techniques, like equalization, compression (source coding), OFDM, MIMO, code division multiplexing, and frequency hopping.

1. Discuss important issues in transmission media as well as transmission and signal processing techniques in networks. 300 Words