How high-precision timing changes the rules of the 5G infrastructure game

“As an important basic technology that has been written into the work report of the Chinese government for 4 consecutive years and has led the “new infrastructure”, 5G is not important in expanding connections, driving economic growth, improving people’s quality of life, and accelerating the digital transformation and upgrading of related industries. It goes without saying.

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As an important basic technology that has been written into the work report of the Chinese government for 4 consecutive years and has led the “new infrastructure”, 5G is not important in expanding connections, driving economic growth, improving people’s quality of life, and accelerating the digital transformation and upgrading of related industries. It goes without saying.

According to the 2020 update of the “5G Economy” report independently researched by IHS Markit, it is estimated that by 2035, 5G will create a global economic output of 13.1 trillion U.S. dollars, and global 5G capital expenditure and R&D investment will increase by 10.8%, with an average annual investment of up to 265 billion US dollars.

According to the latest data from the Ministry of Industry and Information Technology, by the end of 2020, China had added 580,000 5G base stations and promoted the co-construction and sharing of 330,000 5G base stations. The goal of “achieving 5G coverage in all cities and regions” set at the beginning of the year has been achieved.

The number of global 5G connections will exceed 1 billion in 2023, which is exactly 2 years ahead of the 1 billion connections in the 4G era. It can be seen that although the global economy has been affected by the epidemic, the growth trend of 5G-enabled economic output has remained almost unchanged.

Create the most accurate heartbeat of the Electronic system

There are many angles to interpret 5G, but today we want to talk about the clock called the “electronic system heartbeat”.

“Clock IC” is a broad term used to describe an integrated circuit that can generate, modulate, manipulate, distribute, or control timing signals in an electronic system. When applied in the current state-of-the-art electronic and communication systems, clock ICs must also be able to generate precise clock pulses and continuously and reliably distribute the signals for use by various timing devices in the system to meet the needs of many types of applications. The need for precision time service.

In fact, the 4G/5G communication system we are familiar with is one of the important application scenarios of “high-precision timing”. As the 4G/5G network adopts the TDD time division multiplexing mode, in the process of high-rate data transmission, the time synchronization accuracy is extremely high. For example, the time synchronization requirement of the TDD time division system represented by TD-LTE is ±1.5 μs. If the time between communication devices is not synchronized, it will affect the normal operation of communication services such as base station handover and roaming.

How did the network before 5G serve time?

The main source of accurate time in wireless communication networks has always been the Global Positioning System (GPS) and the regional satellite constellations that make up the Global Navigation Satellite System (GNSS). Among them, GPS is the world’s first deployed positioning, navigation and timing (PNT) satellite constellation. With the help of well-designed GPS timing receiver technology, GPS users can recover extremely accurate timing from the synchronized atomic clocks on GPS satellites.

At present, in addition to GPS, a number of GNSS technologies for timing are also deployed worldwide, including Galileo (EU) and Beidou (China). Taking Beidou as an example, the time of the Beidou satellite navigation system is called BDT. When it is atomic, it can be traced to UTC of the China National Time Service Center. The time difference between UTC and UTC is less than 100 ns.

No matter how strong GNSS is, there are shortcomings

Although GNSS satellites have higher timing accuracy and stronger coverage, they also face huge risks-if GPS/GNSS cannot be used due to interference, deception, malfunction or other events, the service interruption caused will cause catastrophic system performance Impact. Just as the power grid is interrupted by fire/snow disasters, 5G networks are also susceptible to the interruption of precise time allocation, which may even cause the entire system to be interrupted.
In addition, from the high-bandwidth video transmission of smart phones to the Internet of Things (IoT) in autonomous vehicles, smart cities, and smart factories, the huge capacity and bandwidth growth brought about by 5G mobile networks is unimaginable before. These new services not only rely on the synchronization of a large number of sensors, base stations and other devices, but also need to transmit very accurate time over long distances, resulting in 5G network endpoint density and the cost of relying on GPS/GNSS for timing.

New time allocation architecture

Operators urgently need solutions that can reduce or even eliminate the reliance on GPS/GNSS. So, is there such a new type of time allocation architecture that can not only allow operators to protect their mobile networks from GNSS interruption, and allocate precise time over long distances to cover the whole country, but also provide the necessary performance to meet 5G End-to-end budget required?

The answer is yes.

The enhanced PRTC (ePRTC) standard is an ideal choice for meeting the challenges of the new timing architecture. It is one of several versions of the Primary Reference Clock (PRTC) defined by ITU-T (ITU Telecommunication Standardization Department) to improve time accuracy. PRTC Class A can meet the 100 ns (nanosecond) accuracy requirement relative to Coordinated Universal Time (UTC); PRTC Class B is more accurate, with an accuracy of 40 ns; enhanced PRTC has a maximum of 30 ns defined by ITU-T G.8272.1 Accuracy.

The unique design of ePRTC gives it maximum flexibility. It can use a cesium clock as a reference clock for 14 days or more, while maintaining the maximum deviation from UTC at 100 ns during the entire long interruption period, which will become a 5G mobile operator Key advantages of deploying ePRTC. If GPS is turned off, the delivery of services throughout the network will be seamlessly switched to ensure that it takes time to repair GPS outages or keep running if GPS is unavailable for a long time.

TimeProvider 4100

A typical example of an ePRTC solution comes from Microchip’s TimeProvider 4100. It can be configured as an ePRTC with PRTC-A and PRTC-B time transfer functions at the source end of the timing chain, or as an HP BC on an optical network path. In addition, this type of product can also be configured according to application-specific requirements to achieve end-to-end timing, and has a nanosecond-level accurate time transfer capability over long distances.

TimeProvider 4100 is a master clock that uses the IEEE1588 protocol, including the latest ITU-T G.8275.1 and G.8275.2 1588 phase specifications, and it also meets the requirements of the Chinese communications industry YD /T 2375-2019 high-precision time synchronization technology standard. TimeProvider 4100 supports a wide range of port extensions for PTP, Network Time Protocol (NTP), Synchronous Ethernet (SyncE) and E1/T1. The 2.1 software version adds key software enhancements to the earlier version and provides a virtual primary reference clock (vPRTC). The virtual PRTC can design a redundant and precise time distribution architecture to perform phase protection on the optical fiber network.

TimeProvider 4100 1GE/10GE expansion module

Microchip’s vPRTC multi-domain architecture is a cost-effective solution that can use the existing optical fiber network and dedicated lambda to accurately and securely transmit time, avoid the use of high-cost dark optical fiber, and provide high performance on regional and national networks , Redundant, accurate time distribution below 5 nanoseconds. In addition, version 2.1 conforms to the PRTC-B performance standard (according to ITU-T G.8272), supports 1G, 10G, Network Time Protocol (NTP) and Precision Time Protocol (PTP) in a single shape parameter system, and introduces information Abstract (MD5) The Network Time Protocol Daemon (NTPd) of the security algorithm.

And Microchip’s version 2.2 of the TimeProviderÒ 4100 master clock product released at the beginning of this year introduced an innovative redundancy architecture based on version 2.1 to provide a new level of flexibility to meet the 5G network’s accuracy in redundancy, resilience and security. The basic requirements of timing and synchronization solutions.

Microchip Version 2.2 TimeProviderÒ 4100 Master Clock Product

Conclusion:

Timing may be the biggest potential failure point in a 5G system, and may affect performance, reliability, and revenue.

Consider how to minimize the use of GPS sites while retaining a highly flexible and precise time structure to ensure the continuity of customer service during GNSS outages? When using a 5G network, how are the network nodes from the source to the end point formed, how time is allocated, and what synchronization functions can these network nodes support? Issues such as these are becoming the biggest concern of operators. As a company that can provide overall system solutions including high-performance clock synchronization, clock management and multiple types of oscillators, Microchip is working with ecosystem partners to create an “electronics The most accurate heartbeat of the system”.