What is the advantage of 5G phone technology

What 5G brings to smartphones

A smartphone with 5G is available for as little as 400 euros, with high-end models the 5G variant costs perhaps ten percent more. In addition, more and more term contracts and also the first prepaid contracts grant access to the new radio network. This makes you wonder, also because the 5G promises sound tempting: campus networks, super-short ping times, edge computing, gigabit downloads, games in real time.

Not all of this actually benefits smartphones. Campus networks, for example, are more likely to improve the networking of machines used in industry or agriculture, especially in real-time applications. Granting employee smartphones access to the campus network is only a side effect, if at all.

Promised download rates

The promised download rates of up to 10 GBit / s only flow in the laboratories of the chip manufacturers. In Germany, due to the restrictions on the frequency bands, at best 2 to 3 Gbit / s would be achievable, and even that only if one provider interconnects all of its bands. But that will not happen for decades because the providers squeeze LTE, GSM and for a while also UMTS into their bands. In addition, they only set up multiple frequencies in metropolitan areas in order to supply a larger number of participants - higher transfer rates can then only be achieved outside of peak hours, for example at night.

For even higher bandwidths you need the so-called mmWave bands from 24 GHz. Test setups sometimes reach 100 GBit / s here, but with technology that is far from being integrated into smartphones. In Germany, the tapes are not even assigned, the expansion will take years, if it takes place across the board at all. Some critics also fear a not yet fully researched health hazard especially in these bands. Therefore, mmWave does not play a role in the current smartphone purchase.

Re-measured

With a Samsung Galaxy S20 Ultra 5G and a Huawei P40 Pro as well as a SIM from Vodafone, we went to Bennemühlen, a small town north of the c’t editorial office in Hanover, where Vodafone operates a 5G test network. In fact, we measured an impressive 200 to 530 Mbit / s here, and the cell was probably empty except for us. In LTE mode, it delivered 50 Mbit / s, other LTE locations in the area were sometimes only 10 to 15 Mbit / s.

The ping times, however, were unimpressively around 25 milliseconds. This may be due to the poor connection of the radio mast in rural Wedemark, the network load during the corona crisis or the lack of software updates in the operator network, as Vodafone explained some time ago. This made the smartphone feel as fast as it is used to with good LTE coverage.

For comparison: In the home office near Hanover's main train station, Vodafone's LTE network pinged at 70 to 190 Mbit / s at 12 to 30 milliseconds, and the Telekom LTE at 60 to 140 Mbit / s at 12 to 25 milliseconds.

Slump in maturity

On the other hand, the runtimes have developed alarmingly. First, we measured the S20 Ultra 5G while playing a YouTube video under constant radio load. In the WLAN it ran for 17.7 hours, so it lost about 5.7 percent of the battery charge per hour. Measured beforehand in the LTE network, the proportion rose to 7.2 percent per hour. In the 5G network, we measured 12.8 percent per hour - so only 7.8 hours extrapolated.

Another test showed that the additional consumption is not due to the high radio load: When a simple website is called up every few minutes, the battery also lost around 12 percent per hour. For comparison, it was around 5.5 percent per hour via LTE. Maintaining the 5G connection therefore costs the electricity, not the data transmission itself.

We suspected the cause was the separate 5G modem in the Galaxy S20 - the Samsung SoC Exynos 990 only has 2G, 3G and 4G built in. We were particularly excited about the measurements with the Huawei P40 Pro, because its SoC Kirin 990 5G is the first available with integrated 5G.

But the results were strikingly similar to those of the S20. In 5G mode, the battery lost around 13 percent per hour both during leisurely browsing and YouTube streaming, in LTE mode around 8 percent for the same actions, and in WLAN mode around 6 percent. Here, too, 5G halves the runtime compared to WLAN.

We hope for firmware updates - or that at least future SoCs with integrated 5G will run better. Next we expect the Snapdragon 765G in the Motorola Edge and Nokia 8.3, for example.

After all: if you switch off 5G in the settings, both phones immediately achieved the LTE runtimes again in the 5G reception range. The power-hungry 5G part is completely deactivated. So if the runtime is no longer sufficient in the 5G area, you should operate the smartphone in 4G mode and only switch on 5G when necessary.

Tape salad

When choosing a smartphone, it is also important to take into account the confusion known from LTE about the supported radio bands. In this country, 5G will mainly run on the N78 (3.5 GHz) band awarded in the 2019 frequency auction, but also on N28 (700 MHz, formerly DVB-T) and when UMTS is switched off on N1 (2.1 GHz). Campus networks use the N77 band (3.7 GHz).

The first generation of 5G smartphones with Snapdragon 855 / Snapdragon X50 and Exynos 9 / Exynos 5100 (see table) only supports N78. It is currently well positioned, but excluded from future 5G networks. One band more is possible with the Kirin 980 / Balong 5000, two bands with the Snapdragon 765 with built-in 5G.

All four tapes that are interesting in this country are available on the Samsung Exynos 990 / Exynos 5123 (S20 family) and Huawei Kirin 990 5G (P40 Pro, Mate Xs and Mate 30 Pro 5G), but even they cannot use mmWave tape. They also do not fully master the other bands 20, 8, 32, 3 and 7 used in Germany for mobile communications, but this is not a restriction because the providers will provide them for LTE and GSM for many years to come.

With import devices you have to be careful like in LTE times. For example, the US version of the Galaxy S20 Ultra 5G (Snapdragon 865 / Snapdragon X55) transmits in N2, N5, N41, N66, N71, N260 and N261 - so none of the 5G bands used in this country can be found. By the way, N260 and N261 are two mmWave tapes - in the EU, however, N258 and perhaps N259 are more likely to be used.

Conclusion

Campus networks are practically useless for smartphones, gigabit speeds cannot be expected across the board for years, and there is no real-time or edge applications to be seen - so does 5G not bring any advantage in smartphones? Except for the small hope of having the 5G cells almost to yourself in the next few years?

A not quite so spectacular, but in practice much more significant increase in speed can be expected in the areas outside of the multi-frequency metropolitan areas. Because here it is possible to achieve data rates with a single 5G band that LTE can only achieve when aggregated with two or three bands. And with perhaps 200 instead of 10 Mbit / s throughout the country and in suburbs, you can start more in everyday life than with 800 Mbit / s, which can only be achieved at night on a lonely exhibition center.

Higher data rates are also not necessary on the smartphone: Huge downloads are rarely carried out and then preferably in the non-data-limited WLAN, HD video streams require less than 10 Mbit / s, even the pointless 4K on a smartphone come with 15 to 25 Mbit / s out. Even those who connect their notebook via mobile phone rarely need more. The higher 5G data rates play more of a role for the home connection, i.e. in the router.

For smartphone users, 5G is therefore not a quantum leap with new fields of application and gigantic download rates - and for what. The new radio technology only allows more users than before to get good data rates even under adverse circumstances. However, you currently pay for this with poorer runtimes and the risk of being locked out of future 5G networks. (yow)


This article comes from c't 9/2020.