Rumors that Apple's new product will support satellite communications have been widely discussed several times, but in fact, the realization of this feature is not out of reach.
In late March this year, the 3GPP completed the functional freeze of the third version of the global 5G standard, Release-17. In the Rel-17 standard, new features of satellite communication were introduced. In addition, rel-17's direct communication will support any type of direct communication between two terminals, which means that the smartphone in your hand can be used like a walkie-talkie, but it is more advanced than a walkie-talkie.
The Rel-17 will also more efficiently support lower complexity IoT terminals, bringing centimeter-level accuracy positioning to better meet the needs of XR (Extended Reality). Many people will expect that the high-speed rail will continue to be connected, and the better battery life performance of 5G mobile phones will also be realized.
What 5G black technology is hidden behind this?
The first phase of the 5G evolution is complete
Mobile communication technology is updated approximately every decade, and during this decade, each generation of mobile communication technology will continue to evolve and improve. Rel-17 is the third edition of the 5G standard and a sign that 5G has completed the first phase of evolution. The next second stage, the 5G standard will also have The second phase of Rel-18/1/20, also known as the 5G Advanced stage.
When 5G was commercially available in 2019, it was based on the first version of the 5G standard, Rel-15, with a focus on enhancing the enhancement of mobile broadband (eMBB) and was also the cornerstone of the evolution of 5G.
The focus of the second version of the 5G standard, Rel-16, is to drive the expansion of 5G into the industry, such as the introduction of support for the licenseless spectrum (NR-U) in this version of the standard. In other words, in addition to the licensed spectrum allocated by the state to operators, 5G applications can also be supported in the unlicensed spectrum, enhancing the flexibility of 5G applications, and Rel-16 has added new functions such as direct communication and positioning.
As a continuation of Rel-16, Rel-17 drives technology development in a number of ways, including capacity, coverage, latency, energy efficiency, and mobility. Some of the key areas of improvement include:
Further enhanced massive MIMO: This project in Release 17 focuses on bringing enhancements to select key technology areas, including enhanced multi-TRP (transmit and receive point) deployments and enhanced multi-beam operation, enhancements in SRS (probe reference signal) triggering or switching, and CSI (channel status information) measurement or reporting.
Coverage Enhancements: For the diverse deployment of Sub-7GHz, millimeter wave, and non-terrestrial networks, Release 17 introduces several enhancements to upstream control and data channel design, such as increasing the number of retransmissions to improve reliability, and combined channel estimation across multi-segment transmission and frequency hopping.
Terminal Power Saving: To further extend the battery life of mobile terminals, Release 17 brings power saving enhancements to terminals in idle/inactive mode and connection mode. For example, this feature supports reduced unnecessary terminal paging reception, relaxation of terminal measurements for wireless links, and other new features.
Spectrum Expansion: Another important project in Release 17 is to extend existing 5G NR designs to extend the millimeter wave spectrum range from 24.25-52.6GHz to up to 71GHz, also known as the FR2-2 band by 3GPP. This feature includes support for the global 60GHz license-free frequency band, enabling new use cases and deployments.
Enhanced IAB and Simple Repeaters: For more efficient 5G deployments, especially millimeter wave deployments, the enhanced IAB (Integrated Access and Backhaul) in Release 17 supports simultaneous transceiver (i.e., space-separated full duplex), and Release 17 introduces a simple repeater (i.e., amplify and forward relay) as a new and cost-effective infrastructure option to help expand network coverage for FDD and TDD.
Further enhanced URLLC, enterprise private networks, and other use cases: Release 17 continues to bring better support to demanding applications such as the Industrial Internet of Things, introducing new enhancements to URLLC (Ultra-Reliable, Low Latency Communications), such as enhanced physical layer feedback, improved license-free spectrum compatibility, in-terminal multiplexing, and prioritization.
To explain in layman's terms, further enhanced massive MIMO enables signals and connections to be more stable as the user moves, and can reduce latency. Both coverage enhancement and terminal power saving are relatively easy to understand, and better signal coverage is achieved from various aspects of communication technology and network deployment.
Spectral amplification is also easy to understand, but it's more on that here. The most important resource of mobile communications is the spectrum, and at the beginning of the commercial use of 5G, the frequency band has included low frequencies below 6GHz and high-frequency millimeter wave bands. At Rel-17, the low-frequency band can reach up to 7.125GHz, and the millimeter wave band is divided into two parts, one is FR2-1, which is the millimeter wave defined in Rel-15 and Rel-16, up to 52.6GHz; the other is The new extended FR2-2 of Rel-17, from 52.6GHz to 71GHz.
That said, starting with Rel-17, the accurate term for 5G spectrum is Sub 7GHz and millimeter wave spectrum.
Dr. Xu Han, head of R&D at Qualcomm China, said, "The previous millimeter wave band FR2-1 can provide a bandwidth of 800MHz, and now the bandwidth of FR2-2 can be as high as 1.6GHz, and even up to 2GHz. ”
Greater bandwidth is like having a wider highway, enabling higher rates, helping to further enhance ultra-reliable, low-latency communications and enable more applications.
Generally speaking, it takes about 1-2 years from the completion of the standard to the commercialization of the product. At present, only The Rel-17 has completed the function freeze, and it will not be completed until the ASN.1 freeze of Thel-17 in June this year, that is, all the details of the Rel-17 are determined, and all the standards of Rel-17 are completed.
From this calculation, commercial products that support Rel-17 will not be commercially available until the second half of 2023 at the earliest, but the new applications that Rel-17 can bring are very worth looking forward to.
New 5G applications to look forward to
Satellite communications
For the average user, the 5G NR support for non-terrestrial networks (NTNs) introduced in Rel-17 may be the most interesting. Satellite communication is divided into many types, including synchronous satellites, low-orbit satellites, medium-orbit satellites and so on.
5G NR for non-terrestrial communications mainly supports two types of terminals: one is CPE-based satellite backhaul communication, such as a satellite receiver that receives satellite TV signals outside the house; the other is direct communication with handheld devices, such as smartphones, IoT devices that support eMTC and NB-IoT capabilities.
"Satellites are very far from the ground, so these two types of terminals can only support low-speed services, but it also makes sense." Xu Hao said, "For example, in areas where there is no signal coverage, a call signal can be sent through a smart phone to tell the subject and location of the satellite to send the signal." Or in more inhospitable areas, there is a need for forest fire prevention or weather forecasting, and in these areas, some sensors can be connected to satellites to achieve communication support for areas that were previously difficult to cover by cellular networks. ”
The more important value of satellite communication is that it can cover almost all locations on the earth, and it is supported as a cellular network that is difficult to cover, and 5G communication with high speed and low latency mainly relies on cellular networks.
High-speed rail communication
After the commercialization of 5G, there is already support for high-speed mobile devices, but the actual experience is not good enough. This is because many people are connected to the nearby base station on the high-speed rail mobile phone, and after the high-speed rail suddenly accelerates, it is easy to drop the bag without switching to the base station along the high-speed rail in time.
Rel-17 defines a priority that tells the phone to switch to a base station along the high-speed rail line in case of high-speed movement, so that a better network experience can be obtained on the high-speed high-speed rail.
Direct-connect communication
Rel-16 first introduced a direct communication function, which means that there is no communication between terminals through the base station, but the direct communication of The Rel-16 is limited to vehicle-to-vehicle communication.
Direct-attached communication and walkie-talkies have similarities, but are more advanced.
The walkie-talkie needs to be pressed to speak, but under direct communication, both parties can communicate at the same time. It is possible to communicate by tuning two walkie-talkies to a channel; but direct communication is more flexible, either through the base station to establish a connection, or by two mobile phones that support direct communication to find each other and connect.
The Rel-17 further expands the direct-connect communication capability to support communication between any type of two terminals, such as a cell phone and a cell phone, a phone and a watch, or a phone and glasses.
Direct communication has many application scenarios: for example, public safety use cases, if the base station can not work normally because of earthquakes and fires and other factors, users can get in touch with the lost family members in time through direct communication between the mobile phone and the mobile phone; in the Internet of Things scenario, two IoT terminals can be directly communicated without connecting to the base station, saving more resources; for example, different users play games in a room, if the terminal can communicate directly without connecting to the base station, higher rates can be achieved. Lower latency and lower power consumption.
According to Leifeng Network, Rel-17 has made a lot of optimizations for the previous version of direct-connection communication, such as enhancing power-saving characteristics and improving resource allocation. There is a good example of resource allocation, in the Rel-16 version, A car needs to know in advance which resources are idle to carry out the next transmission, so as to avoid communication interference and conflicts; in Rel-17, A car can randomly select a resource for transmission, if it is impossible to directly connect to the communication and then monitor to see if there are other suitable idle resources, so that there is no need to detect all resources and then make choices, thereby improving resource allocation, reducing power consumption and improving reliability.
Another optimization of the Rel-17 for direct-connect communications is the introduction of direct-connect communication trunks, which enable greater network coverage. For example, when the A mobile phone cannot be connected to the nearest base station, the A mobile phone may communicate directly with the B mobile phone within the coverage range of the base station network, so that the A mobile phone is eventually connected to the base station.
Xu Hao told Leifeng Network, "Direct-connected communication is suitable for application scenarios with relatively close distances, because its transmission range is limited, basically a relatively small range within a few hundred meters, and the specific range is related to whether it is Line of Sight transmission and the specific transmission environment." The rate of direct communication is also related to the transmission distance, the closer the distance, the smaller the attenuation, and the higher the rate. Direct-connected communications could lead to a range of transformative applications. ”
Unbounded XR
XR includes ar (augmented reality), VR (virtual reality), MR (fusion reality) three technologies, XR is also seen as the entrance to the metaverse. Research on XR is already available in Rel-16; Rel-17 further traffic requirements for XR use cases such as round-trip time, one-way packet delay budget, and packet error rate.
Xu Hao pointed out, "Compared with terminals such as mobile phones, XR terminals are a newly defined terminal type. At present, the relationship between the packets required by such terminals, the packet drop rate and the user experience is not well understood, so it is necessary to explore the traffic requirements and evaluation methods of such terminals, and evaluate the performance of such terminals. At present, XR based on 5G NR has been included in the Research Project of Rel-17, and will continue to promote technological evolution and enhancement in Rel-18 and future versions. ”
In addition to the above applications, Rel-17 narrows the 5G NR design bandwidth (100MHz) to 20MHz in the Sub-7GHz band and 100MHz in the millimeter wave band in order to efficiently support lower complexity IoT terminals (e.g., sensors, wearables, video cameras). In most of the new Sub-7GHz bands (such as n77, n78, n79, n41 and other frequency bands), traditional 5G NR terminals usually need to be equipped with four receiving antennas; this project reduces the number of receiving antennas for NR-Light terminals to one or two. The project also supports energy efficiency gains and the coexistence of RedCap terminals with other 5G NR terminals.
The Rel-17 also further enhances 5G positioning to meet the needs of more demanding use cases, including centimeter-level accuracy. Other enhancements have also been enhanced, such as reduced positioning delay, improved positioning efficiency to expand capacity, and better GNSS (Global Navigation Satellite System) assisted positioning performance.
In addition to RedCap or NR-Light, Non-Terrestrial Network (NTN), Extended Direct Communications, Enhanced Precision Positioning, Extended Broadcast/Multicast, And Unbounded XR, the Rel-17 has a number of smaller 5G system enhancements, including enhanced multi-radio dual connectivity, multi-SIM support, higher-order modulation, sporadic data transmission, quality of experience, data acquisition, and RAN slicing.
The killer app of 5G
The 5G standard has evolved to the third version, why haven't there been killer apps yet? "Killer apps take a certain amount of time to brew, for example, when 3G was done, digital communications have been out for a while, and the launch of smartphones has brought real killer apps." Xu Hao said, "Based on the technical advantages of 5G, we also see a lot of potential applications, such as XR applications, mobile phones to watch 4K or 8K video live is also a good application, 5G millimeter wave applications are also worth looking forward to, another better application is 5G medical applications." ”
The vision of 5G is to change society, which also means that 5G will become ubiquitous, expanding from mobile phones to various vertical applications, which is actually the application supported by the Rel-17 features, but the combination of 5G and vertical industries will take longer.
"Every industry has its own cycle of operation, and it takes some time to change the products in this industry. For example, 5G can provide highly reliable, low-latency connectivity, but to really change the application of robots in the industry, it still needs a certain amount of time to combine 5G with industry applications. Xu Hao pointed out.
Communication technology, as an interaction between the physical world, the virtual world, and the digital world, and one of the most core technologies for realizing the metaverse, needs to evolve continuously. For example, in Rel-17, Qualcomm contributed five key technological inventions: millimeter wave expansion, the introduction of RedCap (NR-Light) terminals, terminal enhancement, the introduction of support for non-terrestrial networks (mainly satellite communications), and the introduction of support for topology expansion.
The 5G Advanced era is coming, and discussions about the 6G standard will also begin around 2025. What exactly is the killer app of 5G?
Note, the picture in the text is from Qualcomm