2.7 Short Introduction to LTE
In the following there will be a short introduction to the basics of LTE. It is, however, not within the scope of the book to deliver a detailed, in depth description of LTE – the following chapter will only describe some of the more basic system properties that useful to know.
For more detail about the deep inner workings of LTE refer to  and .
2.7.1 Motivation behind LTE and E-UTRAN
Due to the ever growing need for higher data speeds for mobile users, new and more efficient methods of utilizing the scarce resources of the RF spectrum is required. 3GPP is an ever evolving standard for accommodating these needs and LTE is yet another step towards higher data speeds, making sure that this new technology is compatible and can co-exist with GSM/EDGE/UMTS.
A decade ago only a few could ever imagine that we would have a need for a mobile system that would support downlink data speeds in the range of 100 Mbps and uplink speeds up to 50 Mbps, utilizing MIMO (see Section 2.6), adaptive modulation schemes up to 64QAM (see Section 2.5) and flexible RF bandwidths from 1.4 MHz to 20 MHz channels. These days we are close to implementing this in reality, utilizing LTE.
Looking at Figure 2.54 puts it all into perspective; the ever increasing need for data speed is accommodated be a constant evolution of mobile access technology. Back in 1992 it was astonishing that you were able to achieve 9.6 kbps over a 200 KHz radio channel on GSM; since then the constant ...