2G, 2.5G, 3G

cellular: 2G/3G
channel bandwidth: 200 kbps (8 time slots) / 5 MHZ
multiple access: TDMA / CDMA

SMS, Short Message Service, up to 160 bytes
SMS, EMS use control channels while MMS use regular channels shared by data and voice.

Data Services

• GSM, Circuit Switching, 9.6 (*2), 12.4(*2, HSCSD)
• GPRS, General Packet Radio Services, Packet Switching, 9.05 kbps/13.4 kbps (*1,2,3,4), speed denoted as *u*d
• EDGE, 3 times of speed of GPRS by using 8-PSK instead of binary GMSK
• 3G, 384kbps, up to 2 Mbps, uplink is 128 kbps
• 3.5G HSDPA (High Speed Downlink Packet Access) 8-10 Mbps (R5), and 20 Mbps (R6) by MIMO, uplink is 384 kbps

Worldwide deployment of HSDPA

WAP, content bearer protocol, certificate, cookies
WML, wireless markup language (or HTML-C as in i-Mode, XHTML)
MMS, Multimedia Messaging Service

Tariff
3G, GPRS vs. GSM
flat rate, data volume or air time

Security features
WIM: A Wireless Identity Module (WIM) can contain
both trusted and client certificates, private keys
and algorithms needed for WTLS handshaking,
encryption/decryption and signature generation.
The WIM module can be placed on a SIM card
and is then referred to as a SWIM card.

authentication and billing of wlan with SIM card

• authentication
• billing
• coverage of both 802.11 & GPRS/3G
• roaming across APs and WISPs
• user base