With the outbreak of video content, today's mobile users are no longer satisfied with the current speed of Internet access, hope that telecommunications providers can provide faster data transfer speeds, and more reliable network services, and next-generation communications technology 5G is in this background Under the birth. Although 5G is still in the planning stage, but the entire industry are working together, hoping to determine the final shape of 5G. But all participants in the industry must agree: As the number of mobile users and their needs rise, the 5G must handle more traffic faster than today's cellular network base stations.
To do this, wireless communications engineers are designing a whole new set of technologies. With these technologies, the delay of 5G data transmission will be less than 1 millisecond (compared with about 70 milliseconds in today's 4G network), and data download peak speeds will be as high as 20Gb / s (4G is 1Gb / s ).
It is unclear which technologies will be the key in the 5G in the long run, but some early technologies have come to the fore. These technologies include millimeter waves, small base stations, Massive MIMO, full duplex and beamforming.
One of the most important issues with today's wireless networks is that more and more people and devices are consuming more data than before, but they are still overwhelmed by the same frequency spectrum that telcos are using the radio spectrum. This means that each person is allocated a limited bandwidth, resulting in a decrease in speed and a dropped call occasionally.
With the increase in the number of devices connected to wireless networks, the issue of the scarcity of spectrum resources has become increasingly prominent. At least for now, we can only share limited bandwidth on a very narrow spectrum, which greatly affects the user experience. The millimeter wave technology is the key to solve this problem.
What is millimeter wave?
Millimeter waves are transmitted at frequencies between 30GHz and 300GHz compared to the bands below 5Ghz previously used for mobile devices. They are called millimeter waves because the wavelengths in these bands range from 1 millimeter to 10 millimeters, and the wavelengths of radio waves used today in smartphones are mostly tens of centimeters.
To date, millimeter-wave applications have been made only on radar systems and satellites. Now, some cellular network providers have begun to use millimeter waves to transmit data between fixed points, such as two base stations, but using millimeter waves to connect mobile subscribers with nearby base stations is a completely new approach.
What are the advantages of millimeter wave technology?
There are generally two ways to increase the transmission rate of wireless transmission: one is to increase the spectrum utilization rate and the other is to increase the spectrum bandwidth. Compared with increasing the spectrum utilization, the method of increasing the bandwidth of the spectrum is simpler and direct. In the same frequency spectrum utilization, doubling the bandwidth can be achieved by doubling the data transfer rate. However, the problem is that frequency bands below 5 GHz nowadays are already very crowded and where to find new spectrum resources? The 5G uses millimeter waves to increase the rate by using the second method.
According to the principle of communication, the maximum signal bandwidth of wireless communication is about 5% of the carrier frequency, so the higher the carrier frequency, the greater the signal bandwidth that can be realized. In the millimeter wave band, the 28GHz band and the 60GHz band are the two most promising bands used at 5G. The available spectrum bandwidth in the 28 GHz band is up to 1 GHz, whereas the available signal bandwidth in each channel in the 60 GHz band is up to 2 GHz (the available spectrum for the entire 9 GHz is divided into four channels).
In contrast, the carrier with the highest frequency in the 4G-LTE band is up and down at 2 GHz, while the available spectrum bandwidth is only 100 MHz. So if you are using the millimeter-wave band, you can easily double the bandwidth of the spectrum by a factor of 10, and the transfer rate can also be dramatically increased.
What are the shortcomings of millimeter wave technology?
In addition to its advantages, millimeter-wave has one major drawback, which is that it can not easily pass through buildings or obstacles and can be absorbed by leaves and rainwater. This is why 5G networks will use small base stations to enhance the traditional cell towers.
Due to the high frequency of millimeter waves and the short wavelength, this means that the antenna size can be made very small, which is the basis for the deployment of small base stations. It is foreseeable that the future 5G mobile communications will no longer rely on the construction of large-scale base station architecture, a large number of small base stations will become the new trend, it can cover the large base station can not reach the distal communication.
At present, the major manufacturers plan to use the 5G frequency band is to use the more traditional 6GHz frequency band in outdoor open areas to ensure signal coverage, while in the indoor use of micro base stations and millimeter-wave technology to achieve ultra-high speed data transmission.
With millimeter waves and other 5G technologies, engineers hope 5G networks will not only serve smartphone users but will also play an important role in driverless cars, VR and the Internet of Things.
Researchers and companies have set high expectations for the 5G and are committed to providing consumers with ultra-low latency and record-breaking data rates. If they can solve the remaining challenges and figure out how to get the entire system to work together, the ultra-fast 5G service is expected to be commercially available over the next five years.
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