Architecture
Cell:
- Covers geographical region
- Base Station (BS): Analogous to 802.11 AP
- Mobile users attach to network through BS
- Air-interface: Physical and link layer protocol between mobile and BS
Mobile Switching Center (MSC):
- Connects cells to wired telephone network
- Manages call setup
- Handles mobility
The first hop
Two techniques for sharing mobile-to-BS radio spectrum (see Multi-Access Protocol):
- Combined FDMA/TDMA: Divide spectrum into frequency channels, divide each channel into time slots
- CDMA: Code division multiple access