5G RedCap is coming soon! But how difficult is it to fully commercialize it?

According to 3GPP's plan, the latest version of the 5G standard R17 will be frozen in June this year. For IoT practitioners, RedCap is one of the most concerned areas in the industry. This is a "low-profile version" of 5G specially launched by 3GPP to enable 5G networks to empower a large number of medium and low-performance IoT scenarios.

At the end of last year, the research topics on the main evolution direction of the first version of 5G Advanced R18 were finalized, and the continuous enhancement of RedCap became one of the key directions, which shows the importance of RedCap in the 5G IoT scenario. The industry has high expectations for RedCap, but in my opinion, its commercialization process should be viewed from a long-term perspective, because in the next few years, the commercialization of RedCap faces huge challenges.

Filling the gap between 5G network capabilities: RedCap is another important evolution of cellular IoT

RedCap stands for Reduced Capability, which is a special direction determined in the 5G R17 stage. Compared with eMBB and uRLLC, it can be said to be a lightweight 5G, but compared with low-power wide area networks such as NB-IoT, its performance is higher. The 5G R16 standard, which has been frozen and put into commercial use, has perfect standards for eMBB, uRLLC and mMTC, but there is no corresponding technical standard for the "middle ground" between the three, so that 5G network capabilities cannot fully cover all wireless scenarios. RedCap fills this "middle ground", so it is of great significance to the improvement of 5G standards and capabilities.

In the discussion of 3GPP R17 research directions, representatives of various manufacturers proposed RedCap's research intentions. The consensus formed in these discussions proposed:

An important goal of 5G is to achieve interconnection and interoperability in industrial scenarios. In industrial environments, scenarios are very complex. For sensor devices, including pressure sensors, humidity sensors, temperature sensors, motion sensors, accelerometers, etc., it is hoped that these sensors will be connected to the 5G access network and core network in the future. 3GPP's multiple technical studies and specifications have described the use cases and requirements of large-scale industrial wireless sensor networks (IWSNs). Such use cases include not only uRLLC services with higher requirements, but also relatively low-end services with smaller device appearance and size. Such services require completely wireless forms to achieve unmanned maintenance, and the battery life can reach several years. Overall, the requirements of these use cases are higher than LPWAN (such as NB-IoT), but lower than uRLCC and eMBB. In addition, in the field of smart cities, some use cases have similar requirements, such as some monitoring scenarios; in wearable device scenarios, including smart watches, smart bracelets, health devices and medical monitoring-related equipment generally require smaller sizes, and the terminal size needs to be reduced under the premise of meeting communication requirements.

Scenarios like these were not considered in the previous 5G R16 version of the standard. If 5G is to support these scenarios in the future, new topics must be proposed, and there are some clear requirements for various use cases. Among them, the general requirements include:

• Equipment complexity: Compared with the high-demand equipment for eMBB and uRLLC defined in Release 15 and Release 16, the main requirement for new equipment types is to reduce equipment cost and complexity, which is particularly evident in industrial Internet scenarios.
• Device size: Most use cases require this, and the new standard should allow for device designs with compact form factors
• Deployment: The system should support FDD and TDD functional deployment in all FR1/FR2 bands

The requirements for specific application scenarios include:

• Industrial wireless sensor network: 3GPP TR 22.832 and TS 22.104 specification documents describe reference use cases and requirements, including 99.99% communication service reliability, end-to-end latency less than 100 milliseconds, reference bandwidth rate less than 2 Mbps, and most devices are stationary, with batteries that can last for at least several years. Of course, for safety-related sensors, the latency requirement is 5-10 milliseconds.
• Smart city video surveillance: As stated in 3GPP TR 22.804, some cost-effective video scenarios require a bandwidth of 2-4 Mbps, a latency of less than 500 milliseconds, and a reliability of 99%-99.9%; higher-level videos require a bandwidth of 7.5-25 Mbps. Of course, the business model of such scenarios is mainly uplink transmission.
• Wearable devices: The reference bandwidth for smart wearable applications is 5-50Mbps for downlink and 2-5Mbps for uplink, with peak rates of up to 150Mbps for downlink and 50Mbps for uplink. The battery of the device should be able to last for several days (up to 1-2 weeks).

According to the definition of 3GPP documents, the research directions for these scenarios are:

• Reduce terminal receiving and transmitting antennas;
• Reduce the terminal bandwidth, and its maximum bandwidth is 20MHz in the Sub 6GHz band;
• FDD half duplex;
• Reduce terminal processing time and terminal processing complexity.

From the description of 3GPP's technical documents, it can be seen that RedCap has many similar performances to the existing LTE in the field of IoT, so it can be used in many scenarios enabled by the current LTE.

In order to promote the evolution of RedCap, R18 has identified the topics for RedCap enhancement, and its main directions include:

• Based on the evaluation method of Rel17, the research aims to further reduce the complexity of user terminals, focusing on reducing the terminal bandwidth to 5MHz in the Sub 6GHz frequency band and reducing the peak rate of the terminal.
• Research technologies to reduce power consumption, including eDRX enhancements, to support lower terminal power levels.

The author looked through the documents on the RedCap discussion at the 94th 3GPP Plenary Session last year and found that most of the manufacturers participating in the discussion mentioned that the enhancement of RedCap should cover LTE Cat.1 and Cat.1 bis, but should not overlap with low-power wide area networks. This proposal eventually formed a consensus, and it can be said that the future R18 version of RedCap will completely replace 4G LTE.

RedCap faces many challenges in full commercialization and needs to be based on long-term development

It can be said that RedCap will open the way for the migration of 4G IoT to 5G, and will play a significant role in the future 4G and 5G generational upgrades. Although the service capabilities that RedCap provides to users are similar to those of 4G, from the perspective of overall network and device performance, RedCap has obvious advantages in the 5G era, mainly manifested in the following aspects: RedCap is a native 5G NR technology that includes all key NR building blocks, such as beamforming, network energy efficiency, etc.; RedCap's equipment supports coexistence on NR carriers, which can be configured to optimize eMBB or uRLLC communication performance.

This advantage is very important for many scenarios, such as the scenario of Industry 4.0. In this fully automated factory scenario, there are a large number of high-performance sensors and mid- and low-end sensors. Therefore, it is necessary to support both time-sensitive communications and delay-insensitive communications. The 5G network can be uniformly configured and optimized to ensure the performance of time-sensitive communications while ensuring that low-end sensor devices still operate effectively.

However, technological advantages may not necessarily be transformed into commercial advantages in the short term. Although the first version of RedCap will be frozen in June this year, its large-scale application in the Internet of Things market still faces many challenges, the biggest of which comes from the current 4G.

First, from the cost perspective, it is expected that RedCap costs will still be higher than 4G in the next few years.

With the freezing of R17, RedCap will usher in the first complete standard version. Considering that it takes nearly two years from the determination of the standard to the release of commercial products, it is estimated that commercial chips and modules will be formed in 2024 and applications in some scenarios will be opened; the R18 standard will be frozen at the end of 2023, and it is expected that commercial terminals supporting R18 will be put on the market after 2025.

Although RedCap will achieve a significant cost reduction compared to high-performance 5G terminals, the initial commercial cost will still be high compared to mature 4G terminals. Currently, the lowest cost of Cat.4 modules has reached about 70 yuan, and the cost of Cat.1 modules has also dropped to less than 40 yuan. However, it took many years and more than 100 million units for the cost of 4G IoT modules to reach this level. The reduction in RedCap costs will inevitably require the test of time and shipments, and it is only possible to achieve the amortization of early sunk costs and fixed costs at a certain scale.

Since RedCap is facing relatively low-value IoT scenarios, its application areas are highly sensitive to costs, which will greatly hinder the application and promotion of RedCap.

Secondly, from the perspective of network coverage, it is impossible to form the same breadth and depth of support as 4G in recent years.

The large-scale application of RedCap also depends on the large-scale coverage of 5G networks. However, at the nodes where RedCap is officially commercialized, can 5G network coverage provide ubiquitous support?

At present, as 2G/3G network withdrawal is deeply rooted in people's hearts, 4G connection has become the main force for the development of cellular Internet of Things, especially Cat.1 connection, which has the fastest growth rate, and this depends to a certain extent on a perfect 4G network. As we all know, my country has built the world's largest 4G network. According to data from the Ministry of Industry and Information Technology, as of the end of 2021, my country has built and opened 5.9 million 4G base stations, accounting for nearly 60% of the total number of base stations. Even remote and rural areas have achieved 4G coverage.

Number of 4G base stations in China (unit: 10,000)

At present, although my country has built and opened more than 1.4 million 5G base stations, according to the "14th Five-Year Plan for the Development of the Information and Communication Industry", by 2025, there will be 26 5G base stations per 10,000 people, that is, the total number of base stations will reach 3.64 million. Since the coverage distance of 5G base stations is much smaller than that of 4G, its coverage breadth and depth are not as good as 4G at this scale. In many IoT scenarios, users may choose 4G terminals.

Thirdly, from the perspective of the terminal cycle, the long cycle characteristics of the Internet of Things make it difficult to replace the existing stock in the future.

Recently, the GSMA released the "Mobile Economy Development Report" predicting that by 2025, China's 4G connections will still account for 53% of total connections, and this data does not include IoT connections, which are mainly smartphones.

According to data from Counterpoint Research, the replacement cycle of smartphones reaches 31 months. With 5G currently accounting for the majority of smartphone shipments, 5G smartphone users will achieve massive growth in the next 2-3 years. However, the update cycle of IoT terminals is relatively long, especially in some unattended scenarios, where many have a life cycle of more than 10 years.

By the end of 2021, the number of cellular IoT connections in my country will reach 1.399 billion, and most of the terminals at this scale are 2G terminals. With the withdrawal of 2G/3G networks, cellular IoT terminals will mainly access the network through 4G and NB-IoT in the next few years, especially Cat.1, which has achieved rapid growth in recent years. GSMA predicts that the number of domestic cellular IoT connections will reach 2.29 billion by 2025. If this scale can be reached by then, the author expects that Cat.1 and NB-IoT will occupy the highest share of the newly added connections, followed by other 4G standards. NB-IoT has been included in 5G and does not overlap with RedCap. Since Cat.1 and other 4G terminals are still in their life cycle, they cannot be upgraded to RedCap within a few years, and it is difficult for RedCap to replace existing terminals.

Finally, the 4G network withdrawal is still far away, and RedCap still needs to take a long-term view

2G networks have been in commercial use for 20 years. In 2020, the Ministry of Industry and Information Technology issued Document No. 25, which formally proposed the withdrawal of 2G networks. However, it is still uncertain when the 2G networks can be completely shut down. 4G has been in commercial use for only more than 8 years. It is currently the most mainstream and very successful mobile communication network. It is in its prime and is expected to continue to play an important role before 2030. It is expected that there will be no consensus on the withdrawal of 4G networks in the next few years.

Looking back over the past few years, the accelerated development of Cat.1 began in 2020, when the 2G/3G network withdrawal reached a consensus and entered a substantive stage. The No. 25 document issued by the Ministry of Industry and Information Technology officially proposed the withdrawal from the network from an official perspective, giving the industry clear expectations. Similarly, after the 4G network withdrawal policy is clarified in the future, RedCap is expected to usher in accelerated growth.

In 2009, with the freezing of 3GPP R8 standards, the first Cat.1 standard was released, and Cat.1bis was further proposed in the subsequent R13 standard. After years of hard work, Cat.1 finally became a major force in cellular Internet of Things, a process that took more than 10 years. The freezing of the RedCap standard can perhaps be seen as an early technical standard reserve, providing the industry with a long-term path to promote the development of cellular Internet of Things, allowing the industry to plan ahead and gradually cultivate this ecosystem, and be able to quickly switch when facing the withdrawal of 4G networks in a few years.