Cell Jammer and Signal Blocker Device in Japan

Japan is one of the most advanced countries in the world. Here, mobile Internet became popular earlier than in the United States and European countries. At the same time, Japan's mobile communication standards are very different from the world. It should be understood that Japan does not have the GSM cellular standard because it is considered outdated. The CDMA second-generation standard is retained from the older generation. However, as in many countries, the use of signal jammers is increasingly a concern for Japanese authorities due to public safety risks and infringement of intellectual property rights.

Regulatory bodies

In Japan, the use of signal jammers is regulated by the Ministry of Internal Affairs and Communications (MIC) and the National Institute of Information and Communications Technology (NICT). These organizations are responsible for monitoring the use of signal jammers in the country and ensuring compliance with rules and regulations.

Legal authorization

The Radio Communications Act was enacted in 1950 and has been regularly updated since then to reflect the latest technological advances. In 2015, regulations regarding signal jammers were added to better protect wireless communications from interference.

In Japan, to obtain authorization to use a signal jammer, an application must be submitted to the Ministry of Internal Affairs and Communications or the National Institute of Information and Communications Technology, detailing the purpose of using the signal jammer and proving that it is necessary for security or research reasons. The applicant must also prove that it can use the signal jammer without causing damage to the communications of other users.

We will look at the different carriers and the frequencies they currently use in the country. Knowing these frequencies is essential if you want to block cell phone signals in Japan.

Mobile Standards

There are several mobile operators in the country: NTT Docomo, SoftBank Mobile and KIDDI. They offer 3G and 4G services using the CDMA2000 and WCDMA standards. In addition, these companies have launched LTE. At the same time, European phones do not support such measures. A Japanese SIM card will most likely not work on a European phone. You will not be able to buy a local card, as all phones in the country use local standards.

If you want to travel around Japan, you are unlikely to be able to buy local phones or maps, as locals will not sell these things to foreigners on short-term visas. Most mobile operators offer postpaid services, but these are expensive for travelers.

Mobile Internet in Japan

Mobile Internet in Japan is quite expensive, and there are no unlimited data plans in the country. In this case, the speed is measured in bytes, not megabytes, as is the practice in other countries. There are several options for accessing the mobile network. It can be used as a regular mobile Internet router or a router to connect devices to the network.

In recent years, the Internet in Japan has become increasingly popular, but it is not yet fully popular, so it may be difficult to connect. Japan's mobile operators use different frequency bands, combining the wide coverage capabilities of low frequency bands and the high-speed data transmission capabilities of high frequency bands to ensure stable 4G and 5G services across the country.

Mobile phone operators in Japan:

NTT DoCoMo
SoftBank
KDDI
Rakuten Mobile

NTT DoCoMo

NTT DoCoMo is Japan's largest mobile communications company, headquartered in Tokyo. It was founded in 1991 and is a subsidiary of Nippon Telegraph and Telephone Corporation (NTT). As one of the world's leading mobile communications companies, the company name "DoCoMo" means "Do Communications Over the Mobile Network" and also means "ubiquitous" in Japanese.

Network Technology and Spectrum Allocation

4G LTE and 5G frequency bands:

4G LTE: Mainly uses 800 MHz, 1.5 GHz, and 2.1 GHz frequency bands to provide users with wide coverage and efficient data transmission.
5G network: Uses 3.7 GHz, 4.5 GHz, and 28 GHz millimeter wave frequency bands to ensure ultra-high-speed data transmission and extremely low latency to support future high-bandwidth requirements.

NTT DoCoMo's 4G LTE network covers the entire country of Japan, providing excellent network quality especially in large cities and densely populated areas.

SoftBank

SoftBank is one of Japan's leading technology groups, founded in 1981 and headquartered in Tokyo, Japan. SoftBank's telecommunications division is one of Japan's three major mobile operators, with major competitors including NTT DoCoMo and KDDI (au). Together, these three companies occupy the vast majority of Japan's mobile communications market.

Main spectrum allocations

4G LTE bands:

900 MHz: used for large-scale coverage, especially suitable for rural and suburban areas, providing good signal penetration.
1.5 GHz: used for medium-range coverage, suitable for urban areas, providing balanced speed and coverage.
2.1 GHz: mainly used in high-density urban areas, providing high data transmission rates to meet high traffic needs.

5G network frequency band:

Sub-6 GHz (such as 3.7 GHz): used for wider coverage and good penetration, suitable for urban and rural application scenarios.
Millimeter wave (such as 28 GHz): provides extremely high data rates, but limited coverage, mainly used in urban centers and high-density areas, supporting ultra-high-speed downloads and high-capacity application scenarios.

KDDI

KDDI Corporation is one of the major telecommunications and mobile communications companies in Japan, with its mobile brand au being one of its core businesses. KDDI was established in 2000 by the merger of KDD and DDI Corporation. Headquartered in Tokyo, KDDI is one of the three largest telecommunications operators in Japan, with major competitors including NTT DoCoMo and SoftBank.

Network Technology and Spectrum Allocation

4G LTE and 5G networks

4G LTE frequency bands: KDDI's 4G LTE network uses frequency bands such as 700 MHz, 1.5 GHz, and 2.1 GHz to ensure high-quality coverage across the country.
5G network frequency bands: KDDI's 5G network uses Sub-6 GHz (such as 3.5 GHz) and millimeter wave frequency bands (such as 28 GHz) to provide high-speed, low-latency, and high-capacity connections to meet the needs of future IoT and smart applications.

Rakuten Mobile

Rakuten Mobile is the mobile communications subsidiary of Japanese e-commerce giant Rakuten. Founded in 2018, Rakuten Mobile, as the fourth largest mobile communications operator in the Japanese market, has broken the market pattern dominated by NTT DoCoMo, KDDI (au) and SoftBank. It is an innovator in Japan's communications industry, achieving low-cost and efficient operations through a unique all-cloud architecture and Open RAN technology. With Rakuten's ecosystem support and innovative network architecture, Rakuten Mobile has rapidly expanded in Japan and attracted a large number of users.

Spectrum Allocation and Network Coverage

Main frequency band

4G LTE band: Using the 1.7 GHz band, covering most of Japan, providing users with stable 4G services.
5G band: Using the Sub-6 GHz band (such as 3.7 GHz) and millimeter wave (such as 28 GHz), 5G services are promoted in major cities in Japan, providing ultra-high-speed, low-latency connections.

In Japan, the frequency bands used by major mobile operators cover multiple frequency ranges to support 4G LTE and 5G networks. These frequency bands vary from operator to operator, and the following is the distribution of some major frequency bands:

4G LTE frequency bands

Band 1 (2100 MHz): NTT DOCOMO, KDDI (au), and SoftBank all use this band, which has a wide coverage and is one of the main LTE bands.

Band 3 (1800 MHz): KDDI and SoftBank use it more, mainly to enhance network capacity in urban areas.

Band 8 (900 MHz): Mainly used by SoftBank, as an enhanced LTE band, it provides better penetration and wide coverage.

Band 18/26 (800 MHz): NTT DOCOMO and KDDI use this band, which has a wide coverage and better signal performance in rural and remote areas.

Band 28 (700 MHz): NTT DOCOMO, KDDI, and SoftBank use it together to enhance the network's indoor coverage and expand services in rural areas.

Band 42 (3500 MHz): A high-frequency band used primarily for high-speed data transmission in urban areas. It is used by NTT DOCOMO, KDDI, and SoftBank.

5G frequency bands

n77 (3700-4100 MHz): One of the main 5G bands used by NTT DOCOMO, KDDI, and SoftBank, which offers high data rates but limited coverage.

n78 (3500 MHz): Used by NTT DOCOMO and KDDI, this band is suitable for high-speed connections in metropolitan areas.

n79 (4700 MHz): Used by NTT DOCOMO, it offers higher bandwidth and is suitable for 5G services in high-density areas.

n257 (26 GHz mmWave): An ultra-high frequency mmWave band used by NTT DOCOMO, KDDI, and SoftBank, which offers very high download speeds, although it has a smaller coverage area, and is suitable for specific areas or hotspot locations.

Rakuten Mobile's frequency bands

As an emerging operator, Rakuten Mobile currently relies mainly on the following frequency bands:

Band 3 (1800 MHz): Rakuten mainly provides 4G services in this frequency band and has developed relatively complete coverage in urban areas.
n77 (3700-4100 MHz): Rakuten is also using this frequency band for 5G deployment to expand its network coverage as much as possible.