5G New Radio (NR) is shaping the future of mobile connectivity, bringing faster speeds and lower latency to users. However, it also presents some challenges, especially regarding uplink coverage, which is crucial for devices sending data back to the network. This blog explores the output power limits of 5G NR, the challenges in uplink performance, and potential solutions to enhance coverage. So, now let us look into Understanding 5G NR and Its Uplink Limitations along with User-friendly LTE RF drive test tools in telecom & RF drive test software in telecom and User-friendly 5g tester, 5G test equipment, 5g network tester tools in detail.

What Is 5G NR?

5G NR refers to the new standards set for 5G wireless technology. Unlike previous cellular technologies, 5G operates at higher frequencies, such as 3.5 GHz and even up to millimeter-wave bands. These higher frequencies allow for faster data rates but come with their own set of challenges, particularly in terms of coverage and penetration in different environments, especially indoors.

Coverage Challenges with 5G NR

In general, the coverage area per cell in 5G networks is expected to be less than in previous generations. This is especially true for indoor settings, where signals can weaken significantly as they pass through walls and other obstacles. The loss of signal strength at higher frequencies is much greater than with the conventional cellular bands, like 1.8 GHz used in LTE.

However, when utilizing 3.5 GHz in a 5G network, an active antenna system can help achieve coverage levels comparable to typical LTE configurations, such as a 2×2 Multiple Input Multiple Output (MIMO) setup. Despite this, uplink coverage—the ability for devices to send signals back to the tower—remains a concern.

Uplink Limitations in 5G NR

The power class for user equipment (UE) in 5G NR is defined as Power Class 3, which is similar to that of LTE. According to the specifications, especially the 3GPP Release 15.3, there is a defined Power Class 2 for the n78 frequency band that helps improve uplink coverage. However, when devices operate in Dual Connectivity mode, which allows them to connect to both LTE and NR networks, the maximum transmitter power isn’t clearly defined.

For practical purposes, when using multiple frequencies, the maximum output power is the total of the power levels at each UE antenna. The user equipment’s ability to transmit effectively is tied to how many power amplifiers it has. Early 5G devices typically support two transmitters but often lack uplink MIMO, which limits their performance. Each frequency band usually has one power amplifier, making single-transmitter devices more cost-effective but less capable in terms of coverage and latency.

Dynamic Power Sharing Among Devices

5G devices can be classified into two types based on their power-sharing capabilities.

1. Type 1 User Equipment: These devices can dynamically share power between LTE and NR, meaning they use a combined modem for both technologies and can achieve higher power levels.
2. Type 2 User Equipment: These devices cannot dynamically share power. They utilize separate modems for LTE and NR and can only function in EUTRA-NR Dual Connectivity under certain conditions.

Both types of devices must adhere to the maximum power constraints set for their classes. For instance, during a single uplink operation, power-sharing can reduce the overall uplink power budget, affecting coverage for both LTE and 5G NR.

Options for Extending Uplink Coverage

Several strategies are being explored to enhance uplink coverage for 5G NR:

1. Uplink Split Bearer with EN-DC: This method allows devices to connect across LTE and NR, utilizing both technologies simultaneously to enhance uplink performance.
2. Carrier Aggregation: By combining frequencies such as 1800 MHz or 700 MHz with 5G NR, operators can improve uplink coverage.
3. Supplemental Uplink: This advanced technique involves switching to a lower frequency when uplink signal quality drops. It allows the full power of the device to be used and can significantly improve coverage and performance.

Uplink Fallback to LTE

Some vendors promote a fallback option that allows devices to revert to LTE when the 5G uplink signal is weak. This system uses an uplink split bearer method to manage connections better. If the 5G network experiences low quality of service indicators (QCI) or poor uplink signal-to-interference-plus-noise ratio (SINR), the system redirects data from the 5G to the LTE network, maintaining a consistent user experience.

Inter-band Carrier Aggregation

Inter-band Carrier Aggregation involves combining multiple frequency bands to enhance uplink coverage. A primary lower frequency band, such as 1800 MHz, can work alongside a secondary 5G NR frequency like 3.5 GHz. This setup maximizes the available resources, although some loss in capacity may occur. This method also requires specific vendor implementations, leading to potential vendor lock-in.

The Role of Supplemental Uplink

Supplemental Uplink (SUL) is one of the most sophisticated methods to boost uplink coverage. When the uplink signal quality deteriorates, devices can switch to lower frequency bands to maintain performance. This transition can extend coverage significantly, sometimes by 4 to 7 dB.

For effective SUL, two uplink carriers can be set up for a single downlink carrier in the same cell. The equipment can switch between LTE and 5G NR rapidly, enhancing the overall performance and user experience.

Making Coverage Decisions

Mobile operators will choose their uplink coverage strategies based on their existing network structures and their plans for the new 5G deployments. The choice of technology vendor will also influence the solutions they implement. Operators must consider whether to pursue vendor lock-in or opt for more flexible solutions.

Conclusion

As 5G technology continues to evolve, understanding the nuances of uplink coverage and the strategies to enhance it is crucial for mobile operators. While 5G NR offers incredible speeds and low latency, the challenges of coverage, especially in uplink scenarios, must be addressed effectively to ensure a seamless user experience. By exploring various techniques such as uplink fallback, carrier aggregation, and supplemental uplink, operators can work toward creating a robust 5G environment that meets the needs of users in diverse situations. Also please find similar articles from here.

James Montano