December 2001
Intermediate to advanced
336 pages
8h 42m
English
Interleaving aims to distribute transmitted bits in time or frequency or both to achieve desirable bit error distribution after demodulation. What constitutes a desirable error distribution depends on the used FEC code. What kind of interleaving pattern is needed depends on the channel characteristics. If the system operates in a purely AWGN environment, no interleaving is needed, because the error distribution cannot be changed by relocating the bits. Communication channels are divided into fast and slow fading channels. A channel is fast fading if the impulse response changes approximately at the symbol rate of the communication system, whereas a slow fading channel stays unchanged for several symbols.
WLAN systems generally assume ...