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5G : Theoretical Aspects | Frequency & Spectrum, Speed, Massive MIMO & OFDM


  • 5G
  • Theoretical Aspects | Frequency & Spectrum...
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5G technology is a brand-new technology that will supply us with data rates that are significantly faster than 4G. It works at frequencies below 6 GHz in many countries. But in future, 5G frequencies will range from 26 to 100 GHz (These frequencies will be used for the 5G backhaul connection, and the end user will connect to a local cell tower utilizing somewhat lower frequency bands, specifically the 1 to 7 GHz bands.). With a 1 millisecond latency, it can deliver multi-gigabit per second data speeds (over the air). The millimeter wave band is chosen for 5G technology. However, 5G is currently being deployed in a large number of countries (almost 60+). Because it operates at the EHF band and has very low on-the-air latency, 5G will lead automation in industries, internet connected vehicles for smooth traffic, tele-medicine, augmented reality (AR), and virtual reality (VR). Three key technologies that will enable 5G are millimeter wave spectrum, OFDM, and massive MIMO. One of the most prominent reasons for developing 5G technology is that the number of internet-connected devices is continually expanding. Due of its large available bandwidth, 5G can manage more devices connecting to the BS at the same time. It has the capacity to handle thousands of devices per square kilometer that are connected to the 5G network.

What's new in 5G Technology

1. Enhanced Mobile Broadband (EMBB)

Users of 4G receive about 10 megabits per second, whereas 5G users receive 100 megabits per second. 5G is predicted to have a peak data throughput of 10 GBits/s, compared to 1 GBit/s for 4G. 5G is expected to have ten times the connection density of 4G. In comparison to 4G, 5G is expected to require less power.

2. Infrastructure for 5G Technology

Because it is a new technology, the infrastructure, equipment, and so on will be considerably different from the current network. In 5G, the coverage zone under a cell will be relatively tiny Because higher frequencies may only travel a limited distance in the earth's atmosphere. Tiny cells are commonly

Also read about what is 5g RAN?
 
referred to as a microcell. Gases, vapor, and other substances in the atmosphere will absorb very high frequency waves. It also has a hard time penetrating thick obstacles because to the increased frequency. As a result, the microcell will be mostly coupled to user devices like PDAs. After that, the microcells will be linked to BS. Then one BS will be connected to another BS through backhaul.

Backhaul is a concept in which a free space LOS channel connects two high BS towers. Simply said, the line of sight path of two high BSs will be unobstructed. However, because the millimeter wave spectrum has more bandwidth, it can accommodate higher data rates. In backhaul communication, the use of wires and fiber optics is reduced. As a result, communication is completely wireless.

3. Dense connectivity and large network capacity

5G is planned to support a connection density up to 10^(6) per square kilometer, which is about ten times more than 4G. The important technologies that will boost the capacity of the 5G network are discussed below.

4. Interference in 5G Network

Interference is a concern since the number of internet-connected gadgets per square kilometer is in the thousands. As a result, it is necessary to eliminate interferences between devices in a very intelligent manner. Precoding in massive MIMO and beamforming will be quite beneficial in this situation.

Key Technologies to enable 5G Technology

1. Extremely high frequency & bandwidth

2. OFDM

3. Massive MIMO

1. Extremely high frequency & bandwidth

In general millimetre wave band is suitable for high data rate communication. Although some frequency band, like, 60 GHz band is easily absorbed by oxygen in atmosphere, but it a good plus for indoor communication.

In comparison to 30 - 60 GHz electromagnetic bands, oxygen in the environment absorbs 60 GHz frequency more. As a result, the 60 GHz millimeter wave band is typically appropriate for indoor communication. Indoor communication has a much shorter range than outdoor communication. Because 60 GHz attenuates significantly with distance, it rarely interacts with outdoor frequency bands. In 60 GHz indoor communication, however, device to device or D2D interference is less. So, it is a big plus for that.

2. OFDM

We've already written an article about OFDM. We covered how OFDM suppresses inter-symbol interferences. When it comes to frequency selective fading, OFDM offers an excellent resistance. It also improves spectrum efficiency.

3. How Massive MIMO increases data rate in 5G

Massive MIMO is critical for 5G communications. Let's pretend that there's simply one transmitter and one reception antenna. Between the transmitter and the receiver, there is only one communication path or data stream accessible. There are four simultaneous paths or data streams between the transmitter and receiver if 2*2 MIMO is used. However, you should be aware that there are two independent paths that a transmitter and receiver could take. Similarly, there are three antennas on the transmitter side and two antennas on the receiver side for 3*2 MIMO. The maximum number of simultaneous data streams between TX and RX is defined as.


Number of simultaneous data stream = min ( M, N)

where, M = number of antennas at transmitter side
N= number of antennas at receiver side

More examples:
If 4*4 MIMO or number of transmitter antenna (antenna element) equal to 4 and number of receiver side antenna = 4; then number is simultaneous data stream between transmitter and receiver is 4.
Similarly, for 5*6 MIMO, number of simultaneous data stream = 5
for 6*6 MIO, it is 6.

In a huge MIMO system, we can get independent eigen pathways using SVD. Signal processing becomes more simple as a result of these independent paths.

Full-duplex radio technology in 5G


In full duplex radio, transmit and receive in the same frequency bands at the same time. Unlike FDD and TDD, when both links use the entire bandwidth at the same time. As a result, self-interference is a critical challenge in full duplex transmission.

#Documentation of next-g wireless communication 5g technology
How many companies have developed multibeam backhaul or point to multipoint wireless products in E band frequency?
What are the handover authentication protocols used in 5g network?




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