Last month, there was big news about mobile carriers launching 5.5G commercial deployments in Hangzhou. An intern at the office started complaining, saying they were still using a 4G plan while leeching off 5G, wondering when they’d ever get to use 5.5G. They also questioned what that extra 0.5G would even do, as if 5.5G had nothing to do with them. Honestly, I’m curious too. I mean, 5G is already pretty powerful, right? I’m not sure I’d even notice an extra half a G of improvement. So, to get to the bottom of this, I did some digging. 5.5G is officially called 5G-Advanced, or 5G-A for short. It’s basically an enhanced version of 5G. The reason everyone calls it 5.5G is simply because it’s more intuitive. It makes it clear that it’s a transition phase between 5G and 6G. We’ve had 2.5G, 3.5G, and even 3.75G before. While the name might not be the most creative, the organization that named it, 3GPP, is a pretty big deal. For over two decades, they’ve been researching everything from 3G to 5G, updating the tech every couple of years. Back in 2017, 3GPP defined several stages for 5G’s development. This year marks the halfway point between 5G and 6G, so naturally, they call it 5.5G. Compared to 5G, the most noticeable improvement in 5.5G is speed. It can reach download speeds of 10 Gbps and upload speeds of 1 Gbps. That’s 10 times faster than the 1 Gbps download speeds of 5G networks. Imagine downloading Genshin Impact in less than 30 seconds with 5.5G! Watching high-definition live streams outdoors would be a breeze. Besides speed, 5.5G also boasts lower latency. While 5G typically has a latency of 5 to 10 milliseconds, 5.5G is expected to bring it down to less than 1 millisecond. This opens up opportunities for XR devices to venture outside the home. These devices not only need high-speed transmission for 4K 60fps XR video but also require real-time interactivity. 5.5G’s two key features perfectly match these needs. However, walking around with XR devices to enter the “metaverse” seems a bit far-fetched right now. It sounds more like they’re inventing a use case for 5.5G. Another major application is passive IoT. As the name suggests, it involves IoT devices that don’t require external power sources. They can harvest radio frequency energy, light energy, or thermal energy from the environment to operate. Although 5.5G’s radio frequency energy is comparable to 5G, the devices consume around 30% less power. Plus, 5.5G is expected to have wider coverage and support more devices, providing better conditions for passive IoT. This might sound like a pipe dream, but last year, logistics vehicles in the Hangzhou Asian Games Village started using passive IoT. It allows for real-time tracking of vehicle locations, facilitating dispatch, and 24/7 monitoring of lithium battery temperatures, eliminating the need for manual inspections. For manufacturing industries, this is a pretty enticing prospect. A passive IoT sensor can cost as little as a few dollars, and there are no maintenance costs. It can be used for cold chain transportation to monitor cargo temperature and location, in factories for real-time material dispatch, and on farms to monitor animals’ body temperature and other health indicators. As for us regular folks, we can expect more low-cost, maintenance-free smart home products in the future… maybe? I’ll believe it when I see it. Back to 5.5G, what makes it surpass 5G? I compared the updates across different 3GPP versions and came across a bunch of new technical terms. I’ll focus on two important ones: Massive MIMO and carrier aggregation. Let’s break down Massive MIMO first. MIMO stands for “Multiple-Input Multiple-Output.” Imagine unloading and loading goods simultaneously – this technology has been around since the 4G era. Think of your phone and the base station as delivery trucks and a courier station, respectively. The transmitted signal is like a package, and antennas are the delivery personnel. 5G uses Massive MIMO, which is like a large courier station. While the scale and number of personnel are better than in the 4G era, during peak delivery times, trucks get stuck, and package handling slows down. 5.5G’s Massive MIMO is like the courier station owner converting the supermarket next door into another courier station. The staff are still numerous and efficient, doubling efficiency. Even during peak hours, package transmission remains fast, and trucks don’t get stuck. Carrier aggregation is easier to understand. When we browse the internet, “carriers” transmit data signals in the background, like conveyor belts carrying packages. A conveyor belt has limited width and can only carry a certain number of packages at a time. Carrier aggregation is like combining several conveyor belts, making the belt wider and increasing package transport efficiency. This technology isn’t new. Carriers used it when 4G was first introduced. The peak download speed back then was only 300 Mbps, and the bandwidth available to a single user was just 20 MHz, far from the ITU’s 4G standards. Only after carriers combined five carriers did 4G achieve the international standards of 1 Gbps download speed and 100 MHz single-user bandwidth. As a tool that can both enhance network speed and efficiently utilize spectrum resources, 5G and now 5.5G have naturally inherited it. However, 5.5G’s aggregated “conveyor belts” are faster and wider, so even without using five, it can achieve the desired effect. Moreover, 5.5G’s way of combining these belts is more flexible and uses “high-speed conveyor belts” that 5G didn’t have. It’s like upgrading the entire transportation line, naturally resulting in faster network speeds. So, 5.5G is definitely fast, and the technological upgrades are impressive. But I’m not exactly losing sleep over it. After all, I spend most of my time at home playing games and watching videos. I rarely need to download large files outside or at train stations. I can’t say it’s useless, but for now, 5.5G feels more like a bonus feature for phones. Following the principle of “something is better than nothing,” if you’re planning to buy a new phone, check if it uses Qualcomm’s X75 or MediaTek’s M80 baseband. Theoretically, such phones will support 5.5G in the future, and several flagship phones have announced OTA updates for it. But if your current phone is still going strong, why not wait a bit longer, at least until 5.5G is readily available everywhere? There’s no rush.