Smartphones for general distribution (so-called SIM-free smartphones) have many product variations and many unique products. However, it is conspicuous that it is left to the judgment of the user who saw the specification table which line can be used. Here, we summarize the compatibility status of smartphones for general distribution released after 2022, which are technically compatible with MVNO using au, UQ mobile, povo, and KDDI lines.
Good compatibility between KDDI network and SIM fleece smartphone for both 5G and 4G
KDDI, which has au, UQ mobile, and povo, is the second largest telecommunications carrier in Japan. Some long-time users may have an image that KDDI’s network has a unique obsession, but in the 4G and 5G era, it is often in line with global technology trends.
Platinum band B18 (B26) is important for 4G
KDDI’s 4G service builds areas with seven frequency bands: B1, B3, B11, B18, B26, B28, and B42. Among them, B18 and B26 in the low frequency band called platinum band are widely deployed and can be said to be an important presence. B1 and B3, which are called 4G core bands, will also be important. B11 is centered in urban areas, but there are few that are compatible with general distribution models. B28 is a platinum band, but the number of base stations is still not so large due to its short history of operation. B42 has a fast communication speed, but the area is centered in urban areas.
In addition, KDDI’s B18 and B26 are the same entity. However, B18 is included in the frequency band designated as B26, and by using the technology “MFBI” that allows the same frequency to be used with multiple band names, B18 can be used as part of B26. B18 is KDDI’s own frequency band, but B26 has a track record of use in the United States and China, so it is relatively easy for global manufacturers to respond.
Support for “au VoLTE” is essential due to the discontinuation of 3G, but there is no problem with recent products
KDDI terminated its 3G service at the end of March 2022, so it is no longer possible to make voice calls using 3G. Therefore, the terminal must be compatible with voice calls “au VoLTE” using 4G. Support for this “au VoLTE” has not been written much in the specification table of the product recently. However, if it is compatible with B18 or B26 that appeared in the last 1-2 years, it can be judged to be compatible with “au VoLTE”. All the products featured this time support “au VoLTE”.
5G is also advantageous because it has both n77 and n78 global bands
KDDI has n77 and n78 as dedicated 5G frequency bands with a narrow area but high speed, n3 and n28 as frequency bands diverted from 4G with a wide area but the same communication performance as 4G, and extremely high speed but extremely narrow area. It uses 5 frequency bands called n257 of millimeter waves. Of these, n257 has technical issues and terminal cost issues, so for the time being, the four frequency bands n3, n28, n77, and n78 will play a leading role. In particular, both n77 and n78 are global bands that are widely used worldwide, so most smartphones for general distribution support both. With this technical background, KDDI’s compatibility with 5G is generally quite good.
You may not be able to use a 5G terminal with a SIM contracted with an au or UQ mobile 4G plan
In this way, the line side is in a fairly favorable situation, but there are points to be aware of on the SIM side. If a SIM card or eSIM subscribed to au’s 4G rate plan or UQ mobile’s old rate plan that does not support 5G is used on a 5G terminal, operation may not be guaranteed and may not work. . In this case, it is necessary to change the contract to a plan for 5G.
Criteria for network support in this article
In this article, the 5G and 4G compatibility levels are judged in four stages based on our own standards. The criteria are as follows. Let’s also discuss emergency alerts and the provision of high-precision location information.
Excellent: Compatible with all n3, n28, n77 and n78. Or one that supports either or both mmWave (n257) or SA mode while supporting n77 and n78.
Good: Compatible with both n77 and n78.
Acceptable: Compatible with either n77 or n78.
Impossible: Those with no corresponding frequency band.
Excellent: Compatible with all of B1, B3, B11, B18 (B26), B28, and B42.
Good: Compatible with B1, B3, B18 (B26).
Acceptable: Compatible with B18 (B26).
Impossible: KDDI’s his 4G is not available.
Emergency disaster bulletin
A well-known emergency disaster alert that notifies you just before an earthquake or tsunami occurs. KDDI currently uses a method called ETWS (Earthquake and Tsunami Warning System). There is also another system called “J-Alert” that also responds to announcements such as missile attacks. “J-Alert” can also be received with the “Yahoo! Disaster Prevention Bulletin” app.
Providing high-precision location information
It is a function that provides highly accurate location information to the other party when calling 110 or 119, and is sometimes called “SUPL”. If you can deal with this, you can save the trouble of explaining your position to the other party in an emergency.
Latest entry iPhone
Apple “iPhone SE (3rd generation)” compatible with 5G
An entry model of the iPhone series that supports 5G. The compact appearance is almost the same as the previous model, the second generation, but the installed SoC is the same “A15 Bionic” as the “iPhone 13” series, and the basic performance has been greatly improved. The general distribution model (so-called SIM-free) sold by Apple and consumer electronics retailers has the same specifications, including communication performance, as those sold by communication carriers including au.