 using packet networks and several approaches to its deployment and design. Then the discussion moved to timing performance in packet networks with a detailed breakdown of the metrics behind time error, asymmetry, and PDV. Then this knowledge was applied to clock per- formance, describing the performance of both reference sources and PTP clock types. This was re- inforced with examples of how to use this information for budgeting an end-to-end network time error. The chapter finished with a general examination of the performance issues that can arise when transporting timing through packet transport systems and what can be done to control and remediate those systems. The chapter concluded with two use cases from the power and cable industries, showing the different timing issues those industries are currently concerned with. Now that you have an overview of all the aspects that must be considered in the design and deploy- ment of a synchronization solution, it is time to take a very detailed look at one specific application. So, Chapter 10 will detail the requirements for timing for the mobile applications, and Chapter 11 will thoroughly examine the possible solutions to deliver upon those requirements. But again, these lessons apply more widely than just mobile, although the mobile case is a very well-documented example to examine. Part IV: Timing Requirements, Solutions, and Testing Chapter 10. Mobile Timing Requirements In this chapter, you will learn the following: Evolution of cellular networks: Covers the generations of cellular networks and how they have evolved from the first generation to the fifth generation. Timing requirements for mobility networks: Discusses the various modulation techniques and how they have evolved and been adopted in mobile networks. Also explains how synchron- ization requirements have evolved along with each change in modulation technique. Timing requirements for LTE and LTE-A: Briefly discusses modulation techniques and use cases implemented by Long Term Evolution. Several use 