5G Cellular Technology Tutorial Includes:
5G Technology 5G Requirements 5G NR, New Radio 5G NG NextGen Network 5G waveforms & modulation 5G multiple access scheme 5G mmWave Massive MIMO & beam-forming Frequency bands & channels Data channels: physical, transport & logical
The 5G new radio, 5G NR utilises a variety of different frequency bands. Like the other mobile communications systems, the frequency allocations are located in a variety of areas of the radio spectrum.
The allocation of the 5G mobile communications frequency bands is typically undertaken by international agreement, although the numbering is undertaken by 3GPP. This reduces the levels of interference and and enables roaming to be undertaken more easily - the more bands there are the more difficult it is to make radios that can roam universally.
With the increasing usage of mobile communications, additional frequencies and bands aree needed to accommodate the 5G technology. Not only are many of the existing bands to be re-used for 5G wireless technology, but new ones are being allocation.
In a new feature for 5G mobile communications, frequencies in the millimetre wave region of the spectrum will be used. The much greater bandwidth available in these regions is very much higher allowing for greater data speeds to be achieved, but the range of the signals is shorter, although this will give better frequency re-usage.
Frequency ranges, FR1 & FR2
Two different frequency ranges are available for the 5G technology and the different ranges have been designated FR1 - frequency range 1 and FR2 - frequency range 2.
The bands in frequency range 1, FR1 are envisaged to carry much of the traditional cellular mobile communications traffic.
The higher frequency bands in range FR2 are aimed at providing short range very high data rate capability for the 5G radio. With 5G wireless technology anticipated to carry much higher speed data, the additional bandwidth of these higher frequency bands will be needed.
Originally the FR1 band was intended to define bands below 6 GHz, but with anticipated additional spectrum allocations, the FR1 range has now been extended to 7.125 GHz.
| Frequency Ranges, FR1 & FR2 for 5G NR
|Frequency range designation||Frequency Range (MHz)|
|FR1||410 - 7 125|
|FR2||24 250 - 52 600|
FR1 5G frequency bands
The frequency bands in FR1 utilise many of the same frequency bands as those used for 4G and other mobile communications cellular services. It is envisaged that over time, the channels and also the bands used for carrying 5G data will take over more of the bands already allocated to mobile or cellular telecommunications. In this way, 5G wireless technology will be able to carry the required traffic levels.
Bands have been set aside for frequency division duplex, FDD usage, or time division duplex, TDD usage. For FDD usage, frequency bands are required for the uplink and downlink, and therefore two bands are allocated. For TDD usage, only a single channel is used for the link: time slots are allocated for the uplink and downlink rather than different frequencies. As a result, for TDD only one band is needed.
| 5G FR1 Frequency Bands
|5G NR Frequency Band||Uplink band (MHz)||Downlink Band (MHz)||Duplex Mode|
|n1||1920 - 1980||2110 - 2170||FDD|
|n2||1850 - 1910||1930 - 1990||FDD|
|n3||1710 - 1785||1805 - 1880||FDD|
|n5||824 - 849||869 - 894||FDD|
|n7||2500 - 2570||2620 - 2690||FDD|
|n8||880 - 915||925 - 960||FDD|
|n12||699 - 716||729 - 746||FDD|
|n20||832 - 862||791 - 821||FDD|
|n25||1850 - 1915||1930 - 1995||FDD|
|n28||703 - 748||758 - 803||FDD|
|n34||2010 - 20225||TDD|
|n38||2570 - 2620||TDD|
|n39||1880 - 1920||TDD|
|n40||2300 - 2400||TDD|
|n41||2496 - 2690||TDD|
|n50||1432 - 1517||TDD|
|n51||1427 - 1432||TDD|
|n66||1710 - 1780||TDD|
|n70||1695 - 1710||TDD|
|n71||663 - 698||TDD|
|n74||1427 - 1470||TDD|
|n75||--||1432 - 1517||SDL|
|n76||--||1427 - 1432||SDL|
|n77||3300 - 4200||TDD|
|n78||3300 - 3800||TDD|
|n79||4400 - 5000||TDD|
|n80||1710 - 1785||--||SUL|
|n81||8800 - 915||--||SUL|
|n82||832 - 862||--||SUL|
|n83||703 - 748||--||SUL|
|n84||1920 - 1980||--||SUL|
|n86||1710 - 1780||--||SUL|
In addition to the FDD and TDD bands, other bands have been allocated to provide supplementary uplink and downlink capacity. The bands marked SDL are for supplementary downlinks and SUL are for supplementary uplinks.
FR2 5G frequency bands
The frequency range 2, FR2 5G bands are now starting to gain momentum with new development to make the microwave links viable for the large scale deployment that will be needed.
Allocations are being made in many areas of the spectrum above 20 GHz as it is relatively lightly used at the moment.
| 5G FR2 Frequency Bands
|5G NR Frequency Band||Uplink band (MHz)||Downlink Band (MHz)||Duplex Mode|
|n257||26 500 - 29500||26500 - 29500||TDD|
|n258||24 250 - 27 500||24 250 - 27 500||TDD|
|n260||37 000 - 40 000||37 000 - 40 000||TDD|
|n261||27 500 - 28 350||27 500 - 28 350||TDD|
5G NR supports carrier aggregation to enable the system to provide the required bandwidth for the very high speed data transfers. The specification allows for up to 16 component carriers to be aggregated using various combinations of inter-band and intra-band carrier aggregation.
The feature can be used in a smart fashion to overcome some of the issues that may occur not only with increased bandwidth, but also to overcome the issues of increased path loss at higher frequencies.
In terms of the allocations above it will be seen that supplementary uplinks, SUL and supplementary downlinks, SDL can be used.
5G NR frequency band parameters summary
There are several different parameters that are specified for the 5G NR physical layer. Sometimes these are specified differently according to the frequency of the 5G NR signal. Aspects like the number of carriers, subcarrier spacing, modulation scheme and a number of other parameters.
The table below summarises the signal characteristics and differentiates them according to their use on frequency band 1, FR1 and frequency band 2, FR2.
| 5G NR Parameters for Different Frequency Bands
|5G NR Parameter||FR1||FR2|
|Bandwidth options per carrier||5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100 MHz||50, 100, 200, 400 MHz|
|Subcarrier spacing||15, 30, 60 kHz||60, 120, 240 kHz|
|Maximum number of subcarriers||3300 (FFT 4096)|
|Carrier Aggregation||Up to 16 carriers|
|Moodulation schemes||QPSK, 16QAM, 64QAM, 256QAM, uplink also allows π/2-BPSK (only for DFT-s-OFDM).|
|Radio frame length||10ms|
|Duplex mode||FDD, TDD||TDD|
|Multiple access scheme|| Downlink: CP-OFDM
Uplink: CP-OFDM; DFT-s-OFDM
|MIMO scheme||maximum of 2 codewords mapped to maximum of 8 layers in downlink and to a maximum of 4 in uplink.|
It is necessary to consult the 3GPP specifications to ascertain the exact details regarding the combinations of transmission bandwidths, for a given frequency band a subcarrier spacing for both FR1 and FR2.
The frequency band allocations for 5G NR are frequently updated as new bands are made available in different countries. Many of the existing 3G and 4G mobile communications allocations will be re-purposed for 5G wireless technology, but this will occur over time as the usage of 5G increases.
Although it is anticipated that more frequency spectrum will be made available for 5G wireless technology over the coming years. It is anticipated that 3G services will be retired first, often before the 3G services, allowing 2G to be used for some signallong applications and 4G as the fallback from 5G.
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