LTE Small Cell Optimization

4 Small Cell Enhancements in Release 12/13

Antti Toskala, Timo Lunttila, Tero Henttonen and Jari Lindholm

1. 4.1 Introduction
2. 4.2 Small Cell and Dual Connectivity Principles
3. 4.3 Dual Connectivity Architecture Principle
4. 4.4 Dual Connectivity Protocol Impacts
5. 4.5 Dual Connectivity Physical Layer Impacts and Radio Link Monitoring
6. 4.6 Other Small Cell Physical Layer Enhancement
7. 4.7 Release 13 Enhancements
8. 4.8 Conclusions
9. References

4.1 Introduction

This chapter covers the small cell enhancements introduced in Release 12 in 3GPP as well as the items on-going for Release 13. First the architecture impacts from the dual connectivity architecture options specified for Release 12 are introduced, and then the dual connectivity principle is covered, followed with the more detailed impacts for the radio protocols as well as physical layer enhancements including 256 QAM and small cell on/off procedures. The resulting performance is introduced. Finally the chapter is concluded with the Release 13 enhancements, including uplink bearer split.

4.2 Small Cell and Dual Connectivity Principles

The 3GPP started the work for the small cell-related improvements following the workshop held in June 2012 on LTE-Advanced evolution, which concluded the need for evolution for the small cell operation. The scenario of importance was especially the use of small cells with a dedicated small cell frequency, as shown in Figure 4.1 as earlier Releases contained already solution such as CoMP or eICIC that can ...