Wireless Network 1. Evolution of Mobile Telecommunication Networks

Martin Cooper

Invented first mobile phone

1G: from 0 to 1

Design philosophy

• idea 1: Cellularization
  • base station
  • communication coverage
  • limited channels
  • cellularization: using smaller stations
• idea 2: Frequency reuse
  • interference occurs when using same frequency
  • use different frequency bands in neighboring cells
  • same frequency band in distant cells (interference minimized)
• idea 3: Core networks for seamless handover (crossing cells)

Frequency Reuse

• why?: Enhance capacity under limited frequency resource
• how?: Clusters (all same freq) -> Cells (all diff freq)
• really useful?:
  • 1008 channels, 6km^2 cell, 2100km^2 total area
  • Cells needed = 350
  • If N=7 (cells per cluster), we need 50 replication (by cluster)
  • Total simultaneous users: C = 1008 * 50
  • If N=4, 88 replication, C = 1008 * 88

1G to 4G: evolution path

• FDM (1G)

  2G: Global System for Mobil Communication (GSM)

• FDM + TDM
• GSM is not connected to the Internet.

  2.5G: General Packet Radio Service (GPRS)

• GPRS is connected to the Internet.
• Circuit switching for classic public telephone network
• Packet switching for internet

  3G: UMTS

• FDMA + TDMA -> CDMA

  4G: LTE

• CDMA -> OFDMA
• All-over-IP (between circuit and packet switching)