Geek Stuff, General

4G, or not 4G – that is the question

Someone asked me this weekend about 4G Wireless; Wikipedia has a good basic description. (Plus I also watched Kenneth Branagh’s Hamlet this weekend (OK, it is Shakespeare’s Hamlet – as interpreted by Branagh) Excellent DVD)

ITU Requirements

This article uses 4G to refer to IMT-Advanced (International Mobile Telecommunications Advanced), as defined by ITU-R. An IMT-Advanced cellular system must fulfill the following requirements:

  • All-IP communications.
  • Peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the ITU requirements.
  • Scalable channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz.[6][6][7]
  • Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth)
  • System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage[6]

Confusion has often been caused by some mobile carriers who have launched products advertised as 4G but which are actually current so-called 3.9G technologies, and therefore do not follow the ITU-R defined principles for 4G standards.