What is the transmission power of 5G smartphones?

Following5G Internet TechnologyThe cost of 5G base stations has increased, especially the problem of high energy consumption. Taking China Mobile as an example, in order to reduce the available long-distance data transmission, its 2.8GHz radio module requires 64 ports and a maximum transmission power of 320 watts.

As for 5G mobile phones that communicate with mobile base stations, they have too close contact with the human body. The bottom line of "radiation hazards" is to try to nip them in the bud. Therefore, they can only fly around in shackles, and their transmission power is strictly limited. The transmission power of 4g mobile phones is limited by the contract to a maximum of 23dBm (0.2 watts). Although this power is not too high, the popular frequency band of 4g (FDD 1800MHz) is low in frequency and the dispersion loss is relatively small. It's not a big problem to use. The situation with 5G is a bit more complicated. Initially, the popular frequency band for 5G was 3.5GHz, which has a high frequency, large path loss, and weak throughput capabilities. In addition, the mobile phone has weak capabilities and low transmit power, so the uplink can easily become a weak point of the system. Secondly, 5G is based on the TDD model, and the uplink is pushed by k-line messages. Under normal circumstances, in order to better ensure the downlink capacity, fewer time slots are allocated to the uplink, accounting for about 30%. In other words, 5G mobile phones in TDD mode only transmit data 30% of the time, which further reduces the average transmission power. Moreover, 5G has flexible deployment models and complex networking solutions. In NSA mode, 5G and 4G transmit data at the same time through dual connections. Generally, 5G is in TDD mode and 4g is in FDD mode. As a result, what should be the transmission power of the mobile phone?

In SA mode, 5G can not only push TDD or FDD single-carrier communications, but also aggregate the carriers of these two modes. Similar to the NSA situation, the mobile phone needs to transmit data in two different frequency bands, TDD and FDD modes at the same time. What should the transmission power be?

In addition, if it is two TDD carrier aggregation of 5G, what should the mobile phone transmit power be? 3GPP has taken full consideration and defined many power levels for smart terminals. In the Sub8G frequency band, power level 3 has a specification of 23dBm; power level 2 has a specification of 26dBm; power level 1 has theoretically higher power, but it has not yet been defined. Due to the high frequency, the millimeter wave communication frequency band has different dispersion characteristics from Sub8G. There are many application scenarios that consider fixed connections or non-mobile applications. The standard defines 4 power levels for millimeter wave communication, and has indicators for radioactive substances. The restrictions are wider. At present, 5G commercial services are based on the mobile eMBB workflow under the Sub8G frequency band. The following will focus on this scenario, focusing on the popular 5G frequency bands (such as FDD n1, n3, n8, etc., TDD n41, n77, n78, etc.) , described in six types.

1. 5G FDD (SA mode): Very high. The transmission power is level 3, i.e. 23dBm;

2. 5G TDD (SA mode): Very high. The transmit power is level 2, i.e. 26dBm.

3. 5G FDD 5G TDD CA (SA mode): Very high. The transmit power is level 3, i.e. 23dBm.

4、5G TDD5G TDD CA (SA mode): Very high. The transmit power is level 3, i.e. 23dBm.

5. 4G FDD 5G TDD DC (NSA mode): Very high. The transmit power is level 3, i.e. 23dBm.

6. 4G TDD 5G TDD DC (NSA mode): The maximum transmit power defined by R15 is level 3, that is, 23dBm, and the maximum transmit power available in R16 version is level 2, that is, 26dBm. Based on the above 6 types, we can see the following characteristics: as long as the working mode of the mobile phone is FDD, the maximum transmit power is only 23dBm, and in the independent networking TDD mode, or when both non-independent networking 4G and 5G are TDD mode, the maximum transmit power can be relaxed to 26dBm. So why is the contract so concerned about TDD? As we all know, whether the ionizing radiation caused by wireless communication is harmful to the human body has always been controversial in the industry, but for the sake of safety, the mobile phone transmit power is strictly limited as much as possible.

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

These health indexes all focus on one indicator: SAR, which is specifically used to detect the health effects of near-field radioactive materials from portable communication devices such as mobile phones. The full name of SAR is Specific Absorption Ratio, which means "specific absorption rate" in Chinese. It is defined as "how much electromagnetic wave mechanical energy from a mobile phone can be digested by a part of the human body's tissues in one second on average." The company is W/kg. my country's national industry standards follow the European standards and clearly stipulate: "The average specific absorption rate (SAR) value of any 10 grams of biological tissue for six consecutive minutes cannot exceed 2.0W/kg." In other words, this type of standard identifies the average value of ionizing radiation produced by mobile phones over a period of time. The power in a short period of time is a little higher, but as long as the average value does not exceed the standard, there is no big problem. If the maximum transmit power in both 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, so the overall transmit power of TDD is higher than FDD is about 5dB smaller. Therefore, paying 3dB for the transmit power of TDD mode is exactly the same as the difference between TDD and FDD under the premise of meeting the SAR standard. Their final average transmit power can reach 23dBm.

Transmitting power of 5G mobile phonesHow big is it? Seeing this, I am sure there has been a response.