How much do you know about how 5G mobile phones are designed to avoid radiation hazards?

alan000345

How much do you know about how 5G mobile phones are designed to avoid radiation hazards? [Copy link]

With the construction of 5G networks, the high cost of 5G base stations, especially the high energy consumption, has become widely known. 5G mobile phones that communicate with base stations have too close contact with the human body, so the bottom line of "radiation hazards" must be strictly guarded. Therefore, they can only dance with shackles and the transmission power is strictly limited.

In NSA mode, 5G and 4G send data simultaneously through dual connections. Generally, 5G is in TDD mode and 4G is in FDD mode. In this case, what should the transmission power of the mobile phone be?

In SA mode, 5G can not only transmit with a single carrier of TDD or FDD, but also aggregate the carriers of these two modes. Similar to the situation in NSA, the mobile phone will send data simultaneously in two different frequency bands, TDD and FDD modes. What should the transmission power be?

Through the above 6 types, we can see the following characteristics: as long as the working mode of the mobile phone appears FDD, the maximum transmission power can only be 23dBm, while in the independent networking TDD mode, or when the non-independent networking 4G and 5G are both TDD modes, the maximum transmission power can be relaxed to 26dBm.

So why do protocols care so much about TDD?

As we all know, there has been a lot of debate in the industry about whether the electromagnetic radiation caused by wireless communications is harmful to the human body. However, for safety reasons, the transmission power of mobile phones must be strictly limited.

At present, various countries and organizations have formulated relevant electromagnetic radiation exposure health standards, which strictly limit the radiation of mobile phones to a very small range. As long as the mobile phone complies with these standards, it can be considered safe.

These health standards all point to one indicator: SAR, which is specifically used to measure the impact of near-field radiation from portable communication devices such as mobile phones on human health.

SAR stands for Specific Absorption Ratio, which means "Specific Absorption Rate" in Chinese. It is defined as "how much electromagnetic wave energy emitted by a mobile phone is absorbed by a part of human tissue on average in one second", and the unit is W/kg.

China's national standard draws on the European standard and clearly stipulates: "The average specific absorption rate (SAR) value of any 10 grams of biological tissue within any continuous 6 minutes shall not exceed 2.0W/kg."

In other words, these standards evaluate the average value of electromagnetic radiation generated by mobile phones over a period of time. The power may be a little higher in short periods of time, but as long as the average value does not exceed the standard, there is no major problem.

If the maximum transmit power in TDD mode and FDD mode is 23dBm, but the mobile phone in FDD mode is always transmitting power, while the mobile phone in TDD mode generally only transmits power 30% of the time, the overall transmit power of TDD is about 5dB smaller than that of FDD.

Therefore, giving the TDD mode a 3dB transmit power compensation is the premise of meeting the SAR standard, narrowing the gap between TDD and FDD, and their final average transmit power can reach 23dBm.

The above content is excerpted from " How high can the transmission power of 5G mobile phones be? "

btty038

As for radiation, as a PA, I am very numb to it because the radiation from mobile phones is really nothing compared to that from other devices.

alan000345

btty038 posted on 2020-8-24 16:13 As for radiation, as a PA, I am very numb to it because the radiation from mobile phones is really nothing compared to the radiation from mobile phones...

Yes, it’s not that great actually, but we still have to pay attention to it now.