mum allowable time error between any two antenna ports (which always also includes the 3 us requirement from 3GPP). Table 10-17 covers the TE requirements for these different categories of timing. Table 10-17 Timing Accuracy Requirements Time Error Requirements at UNI |TE| Category Case 1 3GPP TAE Requirements at Antenna Ports Case 2 Case 1.1 Case 1.2 20 ns relative 65 ns 60 ns relative 70 ns relative 130 ns 100 ns relative 190 ns relative 200 ns relative 260 ns 1100 ns absolute 1100 ns absolute Here are the definitions for the different deployment cases: Case 1: The Telecom Time Slave Clock (T-TSC) is integrated inside the radio equipment, meaning that the final PTP hop ends inside the radio. Case 1 includes two subcases: Case 1.1: The performance of an integrated T-TSC is assumed to be as per ITU-T G.8273.2 Class B specification, including budget of cTE and dTE, which is 60 ns. Case 1.2: An integrated T-TSC is assumed to perform at total maximum absolute TE of 15 ns; could be considered as per ITU-T G.8273.2 Class C T-TSC; and as defined in eCPRI Transport Network V1.2. Case 2: The T-TSC is not integrated inside the eRE or RE but is deployed in a device (like a cell-site router) sitting in front of the radio. The timing signals are delivered to the RE via a physical interface such as the 1 pulse per second (1PPS). One important point to note is that for the Category A+ requirement covering the MIMO and Tx di- versity needs, the TAE number is internal to the equipment specification and does not impose a re- quirement on the transport network. The requirement is still there, but it is between two components "inside the box" and therefore is not a concern for the network engineer. The limit for the absolute time error internal to the RE, or TERE, depends on the case and the cat- egory, as shown in Table 10-18. Table 10-18 Absolute Value of the Internal Time Error, TEeRE/RE, for the Radio Equipment Case 1.1 and 1.2 20 ns 20 ns 20 ns Case 2 22.5 ns 30 ns 30 ns 30 ns Be careful to understand the difference in impleme