4.16 LTE-Advanced (3GPP Release 10–12)
Most of the LTE functionality discussed in this chapter is specified in 3GPP Release 8. Release 9 only contains minor improvements for LTE, one of the reasons perhaps being that the industry was still working on the implementation and deployment of the new system when work started on Release 9 and therefore first had to evaluate the performance of the new system. Major new features to comply with the IMT-Advanced requirements of the ITU are included in 3GPP Release 10, 11 and 12 and are referred to as LTE-Advanced. The major goal of these enhancements is to further reduce cost, to further increase the maximum datarates per user and to improve throughput in cell edge and overlapping cell scenarios. It should be noted at this point that at the time of publication of this book, and for a number of years afterward, it is unlikely that LTE-Advanced functionality except for the carrier aggregation feature will be used in the field. The following sections list some of the most important new features of Release 10 and beyond. Details can be found in the 3GPP work plan , the original feasibility study for LTE-Advanced , Roessler and Kottkamp  and in Rumney .
4.16.1 Carrier Aggregation
A relatively simple way to further increase individual data transmission speeds is to increase the channel bandwidth. To remain backward compatible with 3GPP Release 8, the maximum carrier bandwidth of 20 MHz is not altered. Instead, carrier aggregation ...