The link budget for 5G is more complex and demanding than for 4G due to the higher frequencies, wider bandwidths, advanced modulation schemes, and the use of massive MIMO and beamforming technologies. Effective planning and optimization are crucial to ensure reliable and efficient 5G network performance. Below picture shows 5G link budget factors.
The following table describes the differences between 5G and 3G/4G link budgets for various link factors:
| Link Factor | LTE Link Budget | 5G NR Link Budget |
|---|---|---|
| Feeder Loss | RRUs are used, with external antenna feeder loss. | AAUs are used, without external antenna feeder loss. RRUs are used, with external antenna feeder loss. |
| Base Station Antenna Gains | A physical antenna associates with a single TRX. The antenna gain of a single TRX is the gain of a physical antenna. | A massive MIMO antenna array associates with multiple TRXs. One TRX corresponds to multiple physical antennas. Total antenna gain = Single TRX antenna gain + BF gain – The antenna gain in the link budget is only the antenna gain of a single TRX. – The BF gain is reflected in the demodulation threshold. |
| Propagation Model | Cost231-Hata | UMa/RMa model defined in 3GPP TR 36.873 and UMi model defined in 3GPP TR 38.901 |
| Penetration Loss | Relatively low | Higher frequency band and higher penetration loss |
| Interference Margin (IM) | Relatively large | The massive MIMO beam inherently has interference suppression effect. Therefore, its interference is low. |
| Body Block Loss | N/A | Body block loss needs to be considered for scenarios where UE location is low and the traffic volume is large, especially in mmWave scenarios. |
| Rain Attenuation | N/A | Rain attenuation needs to be considered in mmWave scenarios with abundant and frequent rainfall. |
| Tree Fading | N/A | Tree fading needs to be considered in areas with dense vegetation and LOS. |