4G mobile traffic and 5G network use have grown significantly in recent years, giving rise to multi-antenna and beamforming technologies across the industry.
These technologies have been widely recognised as the evolutionary path towards the next step in 5G technology – 5G-Advanced (5G-A).
On the one hand, multi-antenna technology improves signal transmission speed and reliability, thereby enhancing network capacity and coverage for a better user experience.
On the other hand, beamforming improves the transmission speed and coverage area of signals while reducing power consumption and interference.
Both technologies are also interdependent and gradually converge to benefit each other.
For example, deploying more antenna ports allows for finer and more accurate adjustment of beam directions, resulting in higher beamforming gains.
Industry evolution
Industry’s practices have demonstrated that the implementation of multi-antenna and beamforming technologies follows a clear path:
- Starting from 2TRx
- It advances to 4TRx
- Then 8TRx
- Ultimately reaches Massive MIMO with 32TRx and beyond
This development path aligns with the latest evolution of 3GPP specifications, which have been formulated in response to these technological innovations.
4T4R is the most widely accepted network construction by global operators, with the next stages of the evolution coming in the form of 8T8R and Massive MIMO.
This will bring much-needed capacity increases, and great strides have already been made in this arena – the first FDD 32T32R Massive MIMO solution was released in 2016, and first FDD native 8T8R RRUs in 2020.
“The FDD 32T32R Massive MIMO solution and native 8T8R RRUs support exclusive use of spectrum by 4G or 5G as well as dynamic spectrum sharing between 4G and 5G,” said a telecommunication manufacturing expert.
“Also, FDD beamforming is available on these RF modules,” they said.
FDD beamforming has already won the Best Mobile Technology breakthrough award at the Mobile World Congress 2023.
This reflects the industry’s consensus on the indispensability of these two technologies.
Alternative approaches
Alternative approaches have also been proposed, such as combining 2T2R or 4T4R RF modules into a single shell to achieve 6TRx or 12TRx.
This would combine three RF modules into one, reducing the boxes per site to one, and many people believe that it would save OPEX in RAN, especially in terms of the rental cost of the towers.
Opinions among operators differ, though, as this approach introduces several new challenges:
- Installation complexity – A single 3-in-1 RF module is large and heavy, so a crane is required during site deployment.
- High power supply is required because even a single RF module necessitates a voltage booster module.
- Performance hit – Additional feeders are needed to connect the antennas of the other two sectors, reducing the coverage of each sector by 20%.
- Reliability – A single point of failure in the RF module will affect the services of the entire site, and any component fault requires the entire RF module to be replaced, resulting in a significantly higher failure rate and OPEX per sector.
- Future development – 3-in-one design restricts operators from flexibly expanding capacity by sector.
Due to these hurdles, 3-in-one RF modules have not been widely accepted within the industry, with only a few commercial deployments observed to date.
Multi-band RF modules
Instead, multi-band RF modules (such as dual-band and tri-band) have become more popular as wireless networks use more spectrum.
One of the key reasons for this strategy is future evolution.
For example, operators often deploy one RF module in low bands (such as 700 MHz/850 MHz) and another in middle bands (such as AWS/PCS, 1.8/2.1 GHz).
The low-band RF module evolves to support 4T4R for broader coverage, while the middle-band module evolves to support 8T8R or 32T32R for capacity.
As a result, it is crucial to have Remote Radio Units (RRUs) separated between low and middle bands to ensure evolutionary flexibility.
In summary, multi-antenna, beamforming, and multi-band technologies are the top three trends in the evolution of wireless radio technologies towards 5G-A.
Source
mybroadband.co.za
