The traditional base station time synchronization scheme includes two schemes: direct GNSS (global navigation satellite system, such as GPS / BeiDou), and ground PTP synchronization. The base station directly hangs the GNSS plan to need each base station to increase the corresponding cost, because the future 5G base station quantity will further increase, the investment is huge.

Regardless of the wireless standard, 2G, 3G, 4G and 5G have the same frequency requirements. At present, there is basically no problem with the technology of video frequency keeping frequency synchronization. It is very simple. The key is that 5G now requires more time synchronization than 4G, mainly based on time synchronization.

4G requires 3 microseconds, 3 is UTC equivalent to 1.5, one to the left, the other to the right, and the maximum deviation is no more than 3. Know the definition of TE and TAE, and then look at the request on the right form. 65NR is a special scenario. We have several points to calculate the distance accurately, and to compensate for it. It is no problem to satisfy the operation of automation machinery, and the transmission carrying rate is not large. Continuous narrow waves, including 130, have little impact. Our final consideration is the requirement of 260 ns and 3 microseconds. At the initial stage of 5G, the requirement is the same as that of 4G, and it is also 3 microseconds. The key is 260260, which is also the result of theoretical deduction.

The installation of GNSS antenna has many construction requirements for clearance, lightning protection and property rights disputes. Therefore, the installation of GNSS antenna for indoor equipment is difficult to install and the overall deployment cost is high.

SYN2407E PTP core module

The ground PTP synchronization scheme is complementary and enhanced to GNSS, and has the advantage of high security. However, there are some problems in the traditional scheme: first, the time source equipment. The precision of the time source equipment in the mainstream industry is only 100ns level, and the accuracy is low. Secondly, the end to end time accuracy of the traditional bearer network is us level, which can not meet the requirements of 5G new technology and new scenes for the inter temporal accuracy.