5G has a greater improvement in clock accuracy than 4G, which is reflected in the following two aspects:
1. 5G is less susceptible to clock skew than 4G, and is more susceptible to interference. 4G 10us, 5G low frequency 4us, 5G high frequency 2us; (the more sophisticated the more fragile things), that is, if the GPS signal is disturbed, there is a short time deviation, 5G is very susceptible; and there is still a little After a base station is affected, it will cause many adjacent base stations to be affected;
So what is the response to the bearer network for this problem? Currently there are two functions: A: G8275.1 If there is a large deviation between the two clock sources, there will be an alarm; (but it can't be judged that there is a problem with the clock source signal, so it can't be switched), it can be understood as a better solution than nothing. ; B: Monitor the quality of the clock source. If the offset value is too large (with a threshold) for a period of time, you can set the clock source to be unavailable and switch; (threshold is configurable), but if the clock source Poor quality is a very slow process and may not be monitored; It can be seen that there is no perfect solution to solve this problem.
2. Accuracy problem, although our basic business clock accuracy requirement is +-1.5us, the accuracy requirement of future collaborative services is definitely stricter than this. Because the current inter-station collaborative service agreement is not fixed, wireless is not planned, so there is no Clearly proposed (the previous answer to some customers is +-350ns, leaving the carrier network +-200ns or so), so the range of deviations left for the ATOM GPS solution is very limited. This requires that the location of the ATOM GPS deployment should not be too high; and the risk of blind opening should be considered. Blind opening may easily have more than 200 ns for individual sites;
In the end, the clock scheme may choose is the base station GPS-based +ATOM GPS supplement; but in fact, it seems that the first problem cannot be solved perfectly, but the advantage is that if the GPS of the base station is biased, it will only affect this. Station and some stations around him; and ATOM GPS will affect hundreds of base stations if there is a deviation;
