# 5G UE Data Rate

IMT-2020 specifies the maximum data rate that 5G is required to offer. This is 20Gbps (downlink) and 10Gbps (uplink). This is significant increase compared to IMT-Advanced (4G/LTE Release 14) that offers 1Gbps (downlink) and 50Mbps (uplink).

3GPP gives us a formula to calculate the theoretical peak data rates at Layer 1. Knowing that real-world deployments are unlikely to achieve this, IMT-2020 specifies that "user experienced" data rate should be at least 100Mbps (downlink) and 50Mbps (uplink). This value is 5th percentile value of user throughput that's based on bits correctly delivered to Layer 3.

We should also make a distinction between peak rate, average rate and median rate. Speed tests reporting only peak data rates can be misleading. Often real-world tests will quote average or median rates as well.

## Discussion

• How can I calculate the theoretical data rate in 5G NR for uplink and downlink?

3GPP specifications TS 38.306 shares a formula for calculating the maximum data rate that a UE can support in downlink and uplink. The formula takes into account Carrier Aggregation (CA). The calculation is per component carrier (CC) and then added up over $$J$$ carriers.

Among the constants, $$10^{-6}$$ gives the final value in Mbps. $$R_{max}$$ is 948/1024. This is the maximum LDPC coding rate. The number 12 refers to the number of sub-carriers in a Resource Block (RB). This is multiplied with $$N^{BW}_{PRB}$$, which is the maximum number of RBs that can be allocated to the UE for a given sub-carrier spacing (SCS) and bandwidth. The formula assumes normal cyclic prefix.

Number of layers relates to MIMO layers. Modulation order $$Q_m$$ translates symbols to bits. It takes values 1/2/4/6/8 for BPSK/QPSK/16QAM/64QAM/256QAM.

We divide bits by symbol time $${T_s}$$. There are 14 OFDM symbols per slot, with 1ms slot time at 15kHz SCS. At higher SCS, the slot duration proportionally decreases, translating to higher data rates.

• Could you explain the scaling factor and overheads in the UE data rate formula?

Scaling factor $$f$$ can take values 1, 0.8, 0.75 and 0.4. It relates to MIMO layers and modulation order that are considered per band combination in the formula.

Consider for example a UE whose Baseband Processing Capability (BPC) is 100MHz, 4 layers and 256QAM. Suppose this UE is configured for two component carriers. Due to BPC, the UE can support only two layers for each CC, resulting in a scaling factor is 0.5. Alternatively, the UE may be configured to use four layers for each CC but a lower modulation order 64QAM is used instead, resulting in a scaling factor is 0.75. Scaling factor is configured via RRC signalling.

Overhead $$OH$$ ranges from 8% (FR1 UL) to 18% (FR2 DL). This is due to PHY signalling, typically including SSB, TRS, PDCCH, DM-RS, PT-RS, CSI-RS, PUCCH and SRS. We note that downlink mmWave transmissions have the highest overhead.

• How do I calculate the data rate for the multi-RAT case?

For a UE using both E-UTRA and 5G NR, called Multi-RAT Dual Connectivity (MR-DC), rates are calculated separately for each Radio Access Technology (RAT) and then added up. E-UTRA rate that can be computed using E-UTRA's Transport Block Size (TBS). Data rate in Mbps is given by,

$$10^{-3}\cdot\sum_{j=1}^J TBS_j$$

This considers $$J$$ E-UTRA component carriers in MR-DC band combination. $$TBS_j$$ is the maximum number of transport block bits in either DL-SCH or UL-SCH channels transmitted over a 1ms Transmission Time Interval (TTI) for the j-th CC. This factors in the number of MIMO layers used for that CC.

• Could you show some sample calculations of 5G UE data rates?

Consider FR1 data rate for a single CC. Parameters to use are 8 layers, 256QAM (value 8), scaling factor 1 and overhead of 0.14. Given 60kHz SCS, the equivalent numerology µ is 2. At 100MHz bandwidth, the number of RBs is 135. The calculated data rate is 4623Mbps. Instead, if we use 30kHz, at 100MHz we get 273 RBs. This gives us a slightly higher rate of 4674Mbps.

In FR2, we limit to 2 layers but move up to 120kHz SCS at a bandwidth of 400MHz. Numerology µ is 3. We get 264 RBs. Overhead rises to 0.18. The calculated data rate is 4310Mbps. By trading off MIMO layers against bandwidth, we obtain about the same data rate. FR2 gives lower latency but suffers from lower transmission range.

These calculations are only for a single CC. 5G NR allows aggregation of up to 16 CCs. However, maximum aggregated spectrum is 1GHz. Moreover, the total rate that a UE can handle would depend on supported UE categories.

• For 5G NR sidelink channels, how can I calculate the theoretical data rate?

For 5G NR sidelink channels, the above formula gives the maximum data rate. The parameters are almost similar to the case of downlink/uplink data rate calculation but there are a few differences.

In Release 16, sidelink channel is limited to 2 layers of MIMO. Overhead is 0.23 (FR1) and 0.25 (FR2).

• What online resources are available to calculate 5G UE data rates?

5G Tools for RF Wireless has a useful tool for 5G NR data rate calculation. Users can select downlink or uplink, FDD or TDD, number of component carriers, layers, modulation order, LDPC coding rate, scaling factor, SCS and bandwidth. There's also a selection of TDD slot format. The tool computes and displays all values derived from the above inputs.

An alternative is Clarke's calculator.

## Milestones

Jun
2017

LTE-Advanced Pro Release 14 is finalized. LTE-Advanced Pro is specified in Release 13 and 14. This improves on LTE Release 8 and Release 9 with 10x faster downloads and 3x faster uploads. With LTE-Advanced Pro offering 1Gbps downlink data rate, it's also called Gigabit LTE. LTE-Advanced Pro is seen as a suitable migration path to full 5G deployments.

Nov
2017

A report published by ITU-R specifies the minimum requirements for IMT-2020. This specifies data rate, spectral efficiency, user plane and control plane latencies, connection density, energy efficiency, reliability and mobility metrics. For data rate and spectral efficiency, peak and 5th percentile numbers are noted.

Mar
2018

In RAN WG1 meeting, scaling factor is introduced into the UE downlink/uplink data rate formula. This clarifies that the formula is for per band combination.

Mar
2020

Researchers at the University of Toronto publish their findings on how well 5G NR satisfies IMT-2020 requirements. Based on simulations, they find that user experienced data rates meet IMT-2020 requirements.

Dec
2020

Real-world measurements by Opensignal for the period Oct-Dec 2020 show that 5G networks are delivering average speeds better than 150Mbps (downlink) and 20Mbps (uplink). User rating is excellent for video, voice and gaming experience. Philippines and Thailand have benefited the most for video apps compared to their existing 4G networks. It's expected that as networks deploy 5G Core, latency will improve, thus leading to even better experience. However, 5G availability experienced by users is still poor, at 30% in Kuwait, 25% in South Korea and 20% in the USA.

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## Cite As

Devopedia. 2021. "5G UE Data Rate." Version 4, March 24. Accessed 2021-03-28. https://devopedia.org/5g-ue-data-rate
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Last updated on
2021-03-24 03:14:07
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