Initiatives and issues in the 5G communication era


5G Future Service Development

It is expected that various new services such as image 4K, 8K transmission and spatial 3D transmission services will be started, and automobile-related services, medical services, and security services will start.
This is not the only service on mobile devices so far, which is a service that links B2X mobile carriers and users.
The service expanded to each IoT terminal from here means B2B2X, in which field B, where companies other than carriers can provide many services, will increase during B2X.
This service is undergoing technological development to deploy services using many sensors and AI.

5G development expansion in Japan

Carriers are conducting demonstration tests with the aim of commencing commercialization in line with the 2020 Tokyo Olympics and Paralympics.

Pre-service trials have also been conducted at the venue of the Rugby World Cup held last year.


Interpretation of 5G

Attention has been focused on the characteristics, speed, and capacity of NR (New Radio), but this does not mean that the current technical specifications will not be used and that it will not rapidly switch to NR-only communication.
About used radio frequency
eLTE A frequency band called the sub 6 GHz band or sub 7 GHz band, which is 410 MHz to 7125 MHz. This frequency band is conventionally used in LTE / LTE-Advanced, Wi-Fi, etc., and it is easy to relatively limit the technical issues related to frequency-RF characteristics that have been expanded in recent years. Validated RF technologies used in W-CDMA) and 4G (LTE / LTE-Advanced) can be used.
In the frequency range from around 24 GHz to about 100 GHz, studies are first conducted at 24250 MHz to 52600 MHz, and this frequency band is called the millimeter wave band. The use of this frequency band is not so advanced, so it has the feature of securing a wide frequency band and easily adapting to high-speed and large-capacity, but the attenuation in the atmosphere is large, and the use experience in mobile communication is poor. , There are many issues that need to be cleared technically. In fact, the millimeter wave band is an important part of 5G, but it is necessary to use a combination of millimeter waves and sub-6 GHz (sub-6 GHz) frequency bands. Among the multiple frequency bands to be allocated for NR, 3.3-3.8 GHz band and 4.4-5.0 GHz band are expected to have early service-in as frequency bands for mobile communication. In fact, the United States, Europe and Asian countries have already opened up this spectrum for 5G allocation. In addition, the abundant frequency resources available in this frequency band will be attractive to carriers. It is expected that the NR bandwidth below 50 GHz will extend the frequency band up to 86 GHz.

Current Status of each Country

In China, plans for stand-alone operation in the sub-6GHz band are ahead. This is the world’s first commercialization of 5G communications, and among the three major features of 5G communications, it realizes ultra-reliable and low delay, which was difficult with conventional 4G, and has enabled a variety of technologies such as augmented reality (AR). It seems that 5G communication use in various industries will precede.
There are two operation modes. One is an operation method that uses NSA (non-standalone) 5G frequency band (eLTE and NR) in combination with conventional LTE, and the other is SA (standalone) and 5G frequency This is an operation method that performs from the control between the base station and the terminal to the data transmission / reception in the band (eLTE or NR) alone.


The operation methods of each country that are currently being implemented are as follows.

Sub-6GHz(600 / 700MHz, 2.3 / 3.5 / 4 / 5GHz)SA (Standalone)USA, China
Sub-6GHz(600 / 700MHz, 2.3 / 3.5 / 4 / 5GHz)NSA(None-Standalone)USA, Europe, Korea, Japan
Milli-Wave (28 / 39GHz)NSA(None-Standalone)USA, Korea, Japan


Forecast of gradual increase in the number of base stations

The assumptions of base stations deployed by age are as follows.
2019 ~ (2020 ~) 5G compatible area and 4G area mixed from major urban areas
In the 5G area, 4G compatible eLTE mainstream and NR (phase 1 start) are mixed
2022 NR system changes to phase 2 Supports 5G globally
2030: Full integration of IoT and full-scale service development
However, at this time, there is a possibility that the communication method has already shifted to the next generation 6G.]


Performance required for base stations

For eLTE, it is said that the number of base stations can be operated as it is because the current 4GLTE technology is improved and used. However, when using NR in the millimeter wave band, the direct distance is about 1000 feet (about 300 m). In addition, since communication becomes more unstable when the user enters a building in addition to communication within the building, it is necessary to greatly increase the number of base stations including base stations installed in the building.
5G communication will reduce the load, so far
Terminal → radio wave → transmitting base station → optical line → server → optical line → receiving base station → radio wave → terminal
In short-range communication, communication is performed through each base station.
Terminal → radio wave → base station → radio wave → terminal
The communication assignment is performed by having the base station having the current server function.
In addition, since the optical fiber line speed and communication method for connecting base stations are much higher than the current measured optical fiber speed and capacity, the specifications required for optical lines between base stations (particularly NR) are also current specifications. It is expected that the standard will not require any compromise for the delay and noise that have been allowed until now, and that the performance that exceeds this is required.

Current Status of 5G in early 2020

Actually, the current 5G service is operated in a small part of the United States, where NR (millimeter wave band) is operated, but in other countries, only the service using the eLTE band has been started.
Also, the speed is not as fast as the press release.
It is reported that the actual value of 500 Mbps to 700 Mbps is about 1 Gbps to 2 Gbps of each carrier. This value is close to the speed of ordinary optical lines, not to mention the current mobile communication, and it is certainly excellent at present. This is expected to be due to the same phenomenon as speed reduction due to simultaneous use of optical lines.


Crystal Timing Device market

Reference clock, filter, complementary oscillator (high frequency, low phase noise)
A filter for noise suppression of the transmission signal generated by the reference signal OCXO is required, and development of TCXO to correct the information correctly is urgently required.
It is necessary to complete development of not only NR but also eLTE products before that, and each manufacturer is developing products that make use of their respective strengths.

Until now, the 4GLTE base stations that have been installed have been air-conditioned and operated in a controlled environment, but the NR base station is expected to be installed as a small panel outside and changes in the surrounding environment In particular, performance against temperature changes is required.
This is expected to be equal to or better than the level devices used in automobiles.


Use with satellite communication(VSAT market)

In order to improve the 5G environment, it is essential to use it together with satellite communications. It is expected that an improved VSAT product compatible with the 5G NR frequency of products currently used in commercial satellite communications will be on the market soon.

Space X is currently launching commercial communications satellites, and the number will be significant in the future.

Similar services are expected to be deployed in mountainous areas, seas, islands, etc. where there are no people, and the launch of commercial communication satellites will increase in the future.


Issues that need to be verified for NR

However, among the frequency bands used in 5G, the frequency band classified as NR is close to the frequency used by the current commercial VSAT satellite communication O3bKa-band and the meteorological observation satellite 23.8GHz. It is necessary to have a margin.

Some experts have warned that if the frequency band is close to being recognized as noise, the weather forecast can only be predicted with a system about 40 years ago.

In addition, this NR frequency band will direct millimeter waves to all IoT products in the future.

It is also debated how this affects the human body.


Our Solution and Approach

TCXOs and Filters, which are expected to be the core of 5G and eLTE signal transmission, require timing devices that have advanced into areas that are considered technically difficult, and that satisfy the specifications required by each customer. We are developing In this business, there are many things that simply cannot be dealt with by mass-produced products, so that skilled technology and the selection of the parts to be used are very important.

We manufacture and supply small to medium lot special specification products that are not mass-produced products. If you need something that cannot be handled by mass production (catalog specifications), please contact our sales department.


Next time, we will introduce these special products.

  • Ultra Low Phase Noise Crystal Oscillator
  • Special Custom Crystal Unit #1
  • Special Custom Crystal Unit #2

Please follow and expect our next post.



このサイトはスパムを低減するために Akismet を使っています。コメントデータの処理方法の詳細はこちらをご覧ください