Cellular Network Standards Flashcards
Cellular networks
- Mobile devices - “Cell” phones
- Separate land into “cells”
- Antenna coverages a cell with certain frequencies
- 2G networks
- GSM - Global System for Mobile Communications
- CDMA - Code Division Multiple Access
- Poor data support
- Originally used circuit-switching
- Minor upgrades for some packet-switching
GSM
- Global System for Mobile Communications
- Mobile networking standard
- 90% of the market
- Originally an EU standard - Worldwide coverage
• Used by AT&T and T-Mobile in the United States
• Move your SIM card (Subscriber Identity Module)
from phone to phone
- Original GSM standard uses TDMA to multiplex calls
- Everyone gets a little slice of time
Time-Division Multiple Access (TDMA)
• Multiple streams are combined into a single stream, and then broken out again - “Muxing”
CDMA
• Code Division Multiple Access
• Everyone communicates at the same time
• Each call uses a different code
• The codes are used to filter each call on the
receiving side
- Used by Verizon and Sprint
- Handsets are controlled by the network provider
- Not much adoption elsewhere
4G and LTE
• Long Term Evolution (LTE) - A “4G” technology
• Converged standard (GSM and CDMA providers)
• Based on GSM and EDGE (Enhanced Data Rates for
GSM Evolution
• Standard supports download rates of 150 Mbit/s
- LTE Advanced (LTE-A)
- Standard supports download rates of 300 Mbit/s