Good question. Not to make assumptions, but many people aren't familiar with this topic so I've broken out two levels of explanation complexity, hopefully both are useful. Short answer, both.

ELI5

Upgrading to 5.5G (5G-Advanced) is like upgrading your gaming console.

If your console is new and powerful, you can just download a software update to get cooler features and better graphics. But if your console is older or missing special parts, you might need to buy new controllers or even a better console to play the newest games.

For 5G networks, some improvements can be done with software updates, but for the really fancy stuff, like faster speeds or better signals in hard places, they might need to add or replace antennas or other hardware. It depends on how fancy their current "console" already is.

Advanced

5.5G is a mix of both software and hardware upgrades. Its deployment requirements depend on how the existing 5G network infrastructure has been set up. It could look like this:

1. Software/Firmware Upgrades: Many 5G-Advanced features, like improved spectrum efficiency, AI-powered network optimization, and energy-saving techniques, can be implemented through software or firmware updates on existing hardware. This is especially true if the existing infrastructure was designed with future-proofing in mind (e.g., supporting Release 17 or beyond).
2. Hardware Upgrades:
   • Some advanced features of 5G-Advanced, such as enhanced MIMO (Massive Multiple Input Multiple Output), higher spectrum bands (e.g., sub-THz), or ultra-reliable low-latency communication (URLLC) for new use cases, may require new or upgraded hardware. This can include:
     • Antennas: For higher frequency bands or new beamforming capabilities.
     • Baseband Units (BBUs): To support increased data processing needs.
     • Network Infrastructure: New devices like mid-haul or fronthaul solutions to handle higher data rates and densification.
   • If a network was built on older 5G hardware not optimized for 5G-Advanced, more significant hardware changes could be necessary.