Thomas Kunz
Systems and Computer Engineering
31
Wireless networks in comparison
to fixed networks
nHigher loss-rates due to interference
–emissions
of, e.g., engines, lightning
nRestrictive regulations of frequencies
–frequencies
have to be coordinated, useful frequencies are almost all occupied
nLow transmission rates
–local some
Mbit/s, regional currently, e.g., 53kbit/s with GSM/GPRS
nHigher delays, higher jitter
–connection
setup time with GSM in the second range, several hundred milliseconds for other wireless systems
nLower security, simpler active attacking
–radio
interface accessible for everyone, base station can be simulated, thus
attracting calls from mobile
phones
nAlways shared medium
–secure
access mechanisms important