D (FR1) 3GPP TS 38.133 8 us MRTD (FR2) Clause 7.6.4 24 us MRTD (FR1/2) NR inter-band CA; with or without MIMO or Tx diversity 3 us TAE 3GPP TS 38.104 Clause 7.6.3 NR intra-band noncontiguous CA; with or without MIMO or 3 us TAE (FR1) 3GPP TS 38.104 Tx diversity Clauses 9.6.3.2, 260 ns TAE (FR1) 9.6.3.3 NR intra-band contiguous CA; with or without MIMO or Tx 260 ns TAE (FR1) 3GPP TS 38.104 diversity Clauses 9.6.3.2, 130 ns TAE (FR2) 9.6.3.3 NR MIMO or Tx diversity transmission at each carrier 65 ns TAE 3GPP TS 38.104 frequency Clauses 9.6.3.2, 9.6.3.3 10.6 Summary The different generations of mobile network have always required strict frequency synchronization, and several very effective solutions have been available to address that need. Lately, network engin- eers see that phase/time synchronization has become mandatory for some of the more advanced technologies and techniques in the RAN networks. However, some of these features or services were often not business critical, SO operators always had the option to delay the rollout of new features when they saw that phase/time synchronization was needed to make it work. What has changed now is that 5G has moved from FDD- to TDD- based radio systems, SO deferring deployment of phase and time synchronization solutions is no longer an option. With 5G, the absolute time error limit must be met across the whole mobile network. Within that absolute number, there are other, much smaller relative error limits that must be met between co- operating radio equipment in the front-haul and mid-haul. Some of these limits apply at the UNI- the output of the timing distribution network-or at the output of the radio antenna (TAE). The problem has been clearly defined, and the requirement has been clearly stated, SO the next step is to define a timing distribution methodology to meet those challenges. Chapter 11 discusses the available technologies and techniques for the distribution of timing and how to apply them to the 5G deployment case. Chapter 11. 5G Timing Solutions In this c