Chapter 3
Long-Term Evolution
3.1 Introduction
The steady increase in the number of subscribers to mobile telecommunication systems in recent years, paralleled by a dramatic increase in the average call time and the amount of data transmitted per user, have given rise to a need to work out a new system for mobile telephony that would satisfy the requirements of subscribers. Furthermore, a number of new services have emerged in recent years, including wireless transmission of TV signals to portable terminals. Well-established services such as video-telephony, video-streaming and localization have experienced an ever-growing interest among subscribers. A particular feature of these services is a high diversification of requirements concerning the transmission rate, tolerable transmission delay and acceptable bit error ratio. The International Telecommunications Union has responded to this situation by defining the requirements for a fourth generation system [1]. One of the systems for which the standardization process is already much advanced – in line with the requirements set up by ITU-R for 4G systems – is the Third Generation Partnership Project Long-Term Evolution (3GPP LTE).
The most important requirements identified for the LTE systems can be itemized in the following way [2]:
- Cost reduction in network data transmission (per bit):
- improvement of spectrum efficiency;
- cost reduction in backhaul data transmission.
- Reduction in setup time and round trip delay.
- Improvement ...
