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Enhance 5G Networks with Channel Aggregation, Dual Connectivity, and Massive MIMO


Various technologies are being developed commercially that significantly improve the performance of 5G link networks, both in speed and in signal coverage and range. Among them are channel aggregation (carrier aggregation), dual connectivity and multiple inputs and outputs at a massive level in the antennas (massive MIMO or mMIMO), for one user or even several users. Several recent experiments have managed to exceed five gigabit per second by grouping multiple frequencies and mobile radio antennas, both with SA 5G and NSA 5G networks.

For several years now, people have been talking about MIMO systems, an acronym for multiple input and output data signals from an antenna or antennas of a mobile link network, at the same frequency and even in bulk (mMIMO). The potential of MIMO systems is very high because they allow the link networks to have greater capacity, reduced interference and an increase in the number of users to be covered and the signals also have greater sensitivity, which allows a more precise location of the terminals they are connected and developing new applications for the future.

MIMO systems have long been available on 4G LTE and WiFi networks, especially when operators have needed to expand their mobile network capacity. Massive MIMOs are also common, because it is a fast and efficient way for operators to further increase the capacity of their networks, without the need for more spectrum or increasing the number of base stations. With mMIMO, operators have achieved gigabit capabilities with 5G networks, both in the TDD and FDD bands.

Samsung has reached the most recent transmission record, at 5.23 Gbit / s, followed closely by Ericsson at 5 Gbit / s, with dual connectivity and channel aggregation, with 40 MHz of 4G LTE network and 800 MHz of 5G NR network

Most of the MIMO systems based on 4G LTE networks are of the type 2T2R and 4T4R, which means that a radio signal uses two or four antennas, all of them to transmit and receive the signal, but they can also be 8, 16 , 32 or 64 antennas, and more in the future. Equipment manufacturers have been demonstrating NSA 5G or SA 5G networks of the 64T64R type with operators for a long time. Thus, spectral efficiency is significantly improved by creating multiple signal reception and transmission paths between the base station and the end-user terminal.

As has always been common in telecommunications networks, based on a generic concept and development, such as mMIMO, its possibilities are expanded and improved over the course of a few years. Thus, some antennas can have a very wide coverage radius and a relatively limited range, while others have a very high range but much more precise, similarly to what happens with lamps, which can illuminate a small or small surface very well. a wider one in a diffuse way. Furthermore, the antennas can be oriented vertically or horizontally, with spatially different signal beams. Their combination allows to cover more territory and with different signal strengths, according to the needs of each area.

Initially, mMIMO was used in TDD-type signals, which uses the same frequency for both downloading and uploading data, and this reciprocity of the channel allowed the quality of the information to be the same in both directions of the signal. Subsequently, the biggest challenges that existed with the other type of signal, FDD, have been solved, so that in the end mMIMO is used with both signals, and with different networks, be they 4G LTE, NSA 5G or SA 5G.

Apart from using more antennas, what has been done lately is that the signals work at different frequencies, at low, medium or millimeter bands, which is called channel aggregation or carrier aggregation, either close to or even far from each other. And, to curl the loop, the last thing that has been achieved is that several antennas work at different types of frequency bands very far apart, such as medium and millimeter, in a single terminal, which is known as dual 5G connectivity.

Dual connectivity at more than 5 Gbit / s

On April 14, the Swedish manufacturer of networks and radio stations Ericsson and the Taiwanese MediaTek, which designs among other processors and modems for smartphones, managed to add a medium band signal and another millimeter signal in a single 5G terminal and that it would work at a record speed of 5.1 gigabit per second. But, as the rivalry between manufacturers is maximum, Qualcomm revealed the same day that it had made experimental data calls that combined millimeter spectrum with a mid-band signal, below 6 GHz.

With this experiment, Ericsson and MediaTek believe that they have created new paths to expand the connectivity of the 5G Standalone (SA 5G) networks. “By combining the wide coverage of the bands operating below 6 GHz with the high speed of millimeter waves on commercial hardware and chipset devices, the user experience with 5G is extended by achieving higher connection speed and latency. lower, “they say in a statement.

The demonstration was carried out with the aggregation of 800 MHz (eight 100 MHz carriers) in the 26 GHz millimeter band with another 60 MHz in the 3.7 GHz average band on a single terminal, to reach 5.1 gigabit per second. It is the first time, according to both companies, that a millimeter wave has been combined with another medium band over a SA 5G network, which is known as 5G dual connectivity, or New Radio Dual Connectivity (NR DC). A conventional Ericsson radio station was used over a 5G SA backbone and MediaTek’s M80 5G modem.

With NR DC, users can benefit from high wireless connection speeds both in one direction and the other. And if signals are added, a significant increase in coverage is achieved. It has also been shown that millimeter waves can be robustly used in a new SA 5G architecture when connecting with millimeter or mid-band spectrum, the statement said. “We consider that NR DC will be a very attractive option for many global operators in their 5G SA deployment strategies,” says Haanes Ekstrom, Ericsson’s Head of 5G Trunking Networks.

Qualcomm did not want to be left behind and announced on the same day as Ericsson’s statement that it had managed on March 17 to complete 5G data calls that combine millimeter waves with SA 5G networks in the band below 6 GHz, whether of the type FDD or TDD, in dual connectivity mode. The demonstration was done with a Qualcomm X65 5G modem and a QTM545 millimeter antenna module located inside a smartphone form factor, in a company laboratory in San Diego and with a Keysight emulation 5G network. Ignacio Contreras, 5G marketing manager at Qualcomm, assured that spectrum aggregation, including dual connectivity with millimeter bands and medium bands, is critical to achieve multi-gigabit speeds and very high capacity.

Spectrum added at 5Gbit / s

The aggregation of spectrum in nearby and distant bands to achieve multigigabit speeds is a development that has been achieved for months, at least at an experimental level, and with commercial equipment and networks. At the end of January, the Australian operator Telstra, together with Ericsson and Qualcomm, managed to reach 5 gigabit per second of download speed over a commercial 5G network in the terminal of a single user.

The 5G data call at this speed was obtained with the combination of eight 100 Mhz channels on a 28 GHz millimeter band together with two 20 MHz carriers of a 4G LTE network with carrier aggregation. In its day, Ericsson considered that “a great milestone in wireless communications” had been achieved by using a total of 840 MHz for a record transmission speed.

Last November, Nokia had announced that it had achieved a record 5G speed of eight gigabits per second by combining speeds of various devices, with a Qualcomm terminal and the operator Elisa. However, it is thanks to the aggregation of channels and the combination of the medium frequencies, below 6 GHz, and the very high, or millimeter, above 26 GHz, with dual connectivity, where speeds are being achieved. higher and higher transmission rates.

Ericsson has achieved a peak upload speed of 315 Mbit / s, combining single user MIMO technology with upstream signal enhancement on a 100 MHz channel in the 3.7 to 3.8 GHz band.

For now, it is Samsung who has announced the most recent transmission record, at 5.23 gigabit per second. It was in early March, with the help of dual connectivity and channel aggregation, that this speed was achieved by using a total of 40 MHz of 4G LTE network with 800 MHz of 5G NR network. Specifically, the demonstration in a South Korean laboratory used two 20 MHz carriers in the 1.9 to 2.1 GHz band and eight 100 MHz channels in the 28 GHz band, with end-to-end commercial products. extreme, including a Samsung S20 + commercial terminal, according to Ji-Yun Seol, head of Samsung’s mobile technology group.

Carrier aggregation in the 4G LTE downstream signal was applied to the band below 3 GHz, while millimeter extended wave, with MIMO and broadband channel aggregation with 5G, were applied in the 28 GHz band, in a common core 4G / 5G network. “Dual connectivity basically provides the benefit of greater coverage by combining the two technologies 5G and 4G LTE, especially in this initial stage of commercial 5G deployments and 5G spectrum at millimeter bands,” says Seol.

Dual connectivity allows you to maximize the benefits of 5G and 4G LTE networks and provide higher speeds, both in coverage and reliability. Most of today’s smartphones support dual connectivity and, as many carriers have started to roll out 5G with NSA, Samsung has made dual connectivity supported by NSA 5G networks from the beginning, although it can also be used on SA 5G networks. .

Seol points out that Samsung’s demonstration was made with EN-DC (E-UTRAN New Radio Dual Connectivity) dual connectivity technology, which is used for both SA 5G and NSA 5G. But, he adds, in SA 5G networks there is a way to use 4G at higher speeds through a concept similar to dual EN-DC connectivity called NE-DC, which is a new technology that will be available soon to improve the experience of users of fully 5G networks, with SA 5G.

Continued progress with mMIMO

Progress is not only being made with carrier aggregation or dual connectivity, but also with massive MIMO. Just a week ago, Ericsson managed to achieve a peak upload speed of 315 megabit per second by combining single user MIMO technology with its Uplink Booster technology on a 100 MHz channel of the bandwidth. 3.7 to 3.8 GHz and with a test device equipped with Qualcomm’s X60 5G modem.

This speed of 315 megabits per second seems slow compared to the more than five gigabit per second achieved with the resources mentioned in the previous paragraphs, but Ericsson points out that it is 15 to 20 faster than the average upload speeds that are achieved. today with commercial networks, which in the case of the United States is on the order of 10 megabit per second, as Paul Challoner, vice president of network products at Ericsson points out to Fierce Wireless.

In an OpenSignal report from February, the highest average upload speed was achieved in the Netherlands, at 32.5 megabit per second. But these are actual average speeds for a single user, whereas Ericsson’s is an experimental top speed. Using massive multi-user MIMO (MU-MIMO), the speeds achieved with the addition of multiple layers are several gigahertz per second over 5G networks below 3 GHz. Ericsson, for example, managed to get there last September at top speed 5.4 gigabit per second on a 16-layer multi-user MIMO network in its Texas lab.

However, the progress in the speed and coverage of 5G signals is evident, as well as the greater availability of link networks that offer MIMO technology integrated in a few chips, as the announcement made at the end of March between Samsung and Marvell Technology. , a chip designer for mobile networks. The collaboration between Marvell and Samsung has resulted in the development of an integrated subset (SoC) that manages mMIMO communications on 4G and 5G networks and offers energy savings of up to 70% and a smaller size than previous designs, according to both companies have communicated. This SoC will be integrated into Samsung’s link networks starting this quarter.