Evolution

1G: Analog voice (1980s)
2G: Digital voice (1990s)
3G Mobile data (2000s)
4G Mobile broadband (2010s)
5G "Wireless Edge" (2020s)

Each generations lasts +- 10 years
For each new generation:
First 5 years, a set of requirements are set
The implementers fight and develop
We try to standardise, based on developments
In every generation, we want more throughput, efficiency and reliability (but throughput most of all)

Legacy Architectures

Called cellular because coverage area is divided into regions called cells
Each cell will have 1 base station
When you move form one cell to another, you will switch to a new base station (handover)
Air-interfcae: physical and link-layer protocol between mobile device and base station

2G

Cells are further grouped
Base stations grouped into Base Station System (BSS)
Controlled by a Base Station Controller (BSC)
Linked up to a Mobile Switching Centre (MSC)
MSC hooked up to gateway

3G: Voice + data

Base Station Controller -> Radio Network Controller (RNC)
Adds Serving GPRS Support Node (SGSN)
and Gateway GPRS Support Node (GGSN)
Both are essentially routers
SGSN also does some mobility management

4G

The solution for wide-area mobile internet
Higher peak speeds
Running on 450MHz-6GHz
LTE standard
Came from 3rd Generation Partnership Project (3GPP)

International Telecommunication Union (ITU) came with a new 4G directive:
All IP switched
Higher data rates and better efficiency
Dynamically share network resources
Smooth handovers across heterogenous networks (e.g. 2G 3G)
High quality service for multimedia applications

LTE:
OFDMA: frequency AND time multiplexing
4x4 MIMO for more throughput, availability and signal strength
Modulation up to 64QAM (more bits per symbol)

LTE advanced:
Worldwide functionality & roaming
Interworking with other radio access systems
Enhanced data rated
Relay nodes (repeaters) to increase coverage
5x20MHz bandwidth
8x8 MIMO
Modulation up to 256QAM

• Mobile device
  • e.g. smartphone, tablet. Anything with an IP
  • Has International Mobile Subscriber Identity (IMSI) stored on your Subscriber Identity Module (SIM) card
  • A.k.a User Equipment (UE)
• Base station
  • The "antenna" you connect to
  • Manages radio resources and all devices in its area (cell)
  • Coordinate device authentication based on IMSI with other elements
  • Similar to wifi AP, except
    • Also handles mobility between cells
    • Coordinates with nearby base stations to optimise radio usage (inter-cell interference coordination)
  • A.k.a. eNode-B
• Home Subscriber Service (HSS)
  • Stores info about devices for which this HSS is their "home network"
  • Works with Mobility Management Entity (MME) in device auth
• Gateways
  • Serving Gateway (S-GW) and PDN Gateway (P-GW)
  • On path from device to/from internet
  • P-GW
    • Gateway to mobile cellular networks
    • Looks like any other gateway router
  • Other routers make extensive use of tunnelling
• Mobility Management Entity (MME)
  • Handles device authentication, coordinated with the home network HSS
  • Establishes bath from base station to P-GW (through tunnelling)
  • Mobile device management
    • Handover between cells
    • Tracking/paging device location