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5G, called IMT-2020 (International Mobile Telecommunications) or also 5G NR (New Radio), the successor of 4G cellular systems, is there to break records and allow huge improvements in the services offered to users, but also to make things easier for operators.
IMT-2020 systems will support three types of scenarios, commonly called use cases. The first scenario is Enhanced Mobile Broadband (eMBB). This use case is dedicated to applications requiring very high transmission rates as well as high bandwidth and high user mobility. The bit rate must be maximum to satisfy real time services (Popovski et al., 2018).
Therefore, eMBB 5G system allows bandwidths of at least 100 MHz and up to 1 GHz, and could reach a Peak Data Rate of 20 Gb/s in Downlink (DL) and 10 Gb/s in Uplink (UL), with spectral efficiency of 15 bit/s/Hz in UL and 30 bit/s/Hz in DL. The new technology supports multiple user speeds up to 500 km/h with a mobility interruption time of 0ms (Popovski et al., 2018).
The second use case is Ultra-Reliable and Low Latency Communications (URLLC). As its name suggests, this scenario is used for applications with very critical response time constraints (Ji et al., 2018).
The third scenario is called the Massive Machine Type Communications (mMTC). This use case is dedicated to networks with a large number of connected devices. It examines the battery life of the objects transmitting massive traffic without delay conditions (Popovski et al., 2018).
The URLLC 5G system has latencies of 1ms in the User plane and 10ms in the Control plane, while an mMTC scenario may allow the connection density up to 1 million devices per km2 (Ji et al., 2018).
Table 1 shows the various improvements made to the 4G 3GPP Radio Access Network (RAN) by 5G technology (Shanzhi et al., 2015).
Table 1.
LTE and 5G parameters comparison
| Specifications | E-UTRAN | 5G NR |
| Radio frame duration | 10ms | 10ms |
| Number of slots in a frame | 20 | 20 |
| Maximum number of data subcarriers | 1200 | 1200 |
| Number of RBs | 100 (maximum) | Higher or equal to 100 |
| TTI (Transmission Time Interval) | 1ms | Flexible (TTI = # of symbols * symbol length) |
| Subcarrier spacing | 15 kHz | Flexible: 2n*15 kHz (where, n = 0, 1....,5) |
| Frequency bands | Under 6 GHz | Up to 100 GHz |
| Carrier bandwidth | 1.4/3/5/10/15/20 MHz Up to 100 MHz (Carrier aggregation) | Variable:
• From 100 to 200 MHz (<6 GHz band)
• From 100 MHz to 1 GHz (> 6 GHz band) |
| Beamforming | Applicable to certain transmission modes | With and without DL/UL reciprocity |
| Modulation | Up to 256-QAM | QPSK, 16-QAM, 64-QAM and 256-QAM |
| MIMO (Multiple-Input Multiple-Output) | Up to 8X8 | Up to 8X8 |
| Channel Coding Scheme | Turbo coding for data | • Control plan: NR Polar codes.
• User plan (Data): NR LDPC (low-density parity-check). |