Thomas Kunz
Systems and Computer Engineering
43
GSM Data Properties
nCircuit-switched operation
–uplink and
downlink channels allocated for a user for entire call period
nbusy user uses only one direction of link (typically),
so 50% of resources are
wasted
–user pays
for the connection time, not for the amount of data
nbad connections - more retransmissions - make more money
for operator
npay even if no data is transmitted
–connection
establishment time: 20-25 seconds
nbad for short-lived transactions
–capacity:
9.6 kbps (channel coding designed for worst-case radio situation)
–connections:
to any modem service in PSTN