Experts said that although 5g technology has been greatly improved compared with the previous generation of wireless technology, many of the driving forces driving 5g into the new frequency band come from old-fashioned physics.
It may be difficult to accurately determine the frequency at which 5g technology will be used, in part because 5g technology varies widely from country to country and even from operator to operator. However, most 5g frequencies can be placed in three main groups.
Low end: 650MHz to 1GHz
The lower frequency – from the lowest 650MHz to the highest 1GHz – is especially favored by wireless companies deploying 5g. Signals in this range travel over a relatively long distance, which means that service providers can cover a large area with a single access point.
However, according to Gartner analyst bill ray, using 5g in the lower range of 5g RF spectrum is a serious limitation.
“These frequencies are very popular,” he said
This is a problem because although the channel capacity at the low end is the same as that at the higher frequency, that is, the throughput provided by the 5MHz wide channel in the 850mhz range is the same as that of the 5MHz wide channel in the 2.6GHz range – the lack of available spectrum means that there are only not enough channels to provide the high connection speed advertised by 5g.
In order to achieve higher speed, 5g uses a wider channel. Ray added: “in 3G, the standard transmission is 5MHz wide.”“ In 5g, we are talking about a 100MHz wide slot, so your transmission channel can run between 2.4GHz and 2.5GHz. “
Middle: sub-6ghz and spectrum peak
Most of the performance and efficiency improvements promised by 5g technology depend on the “sub-6ghz” range close to the spectrum part of Wi Fi – between 2.4GHz and 6GHz, which is a deviation for service providers who are used to lower it.
Patrick Filkins, senior research analyst at IDC, said: “the frequency band below 6GHz is a new spectrum for them. This means greater channel and delay improvement. “
Another problem is that there is available spectrum in this frequency band, especially in the citizen broadband radio service / Universal authorized access (CBRS / GAA) spectrum between 3.5GHz and 3.7GHz. The spectrum uses the priority access system. Users have obtained the first frequency division, but other users may use the frequency anywhere that does not interfere with these users. Needless to say, operators are interested in spectrum.
As operators compete for their valuable spectrum, 5g coverage will continue to expand, and its advantages in Wi Fi will become more obvious in a specific aspect. 5g spectrum is allocated to one license holder in each geographical area, while Wi Fi does not provide such exclusivity; Anyone can use it anywhere, which paves the way for signal overlap and interference.
“Cellular deployment is deterministic – one of its biggest advantages over Wi Fi is that it can overcome the unsolved interference problem of Wi Fi,” Filkins said
High end: millimeter wave
All the optimizations and complexities of 5g are high, but it still needs a lot of bandwidth to achieve its promise of Gigabit throughput. Although the wireless industry actively pursues bandwidth at lower frequencies, there is still not enough available space in the more ideal range of 6GHz and 1GHz.
Millimeter wave technology, its operating frequency range is 24GHz to 60GHz, depending on the experts you talk to and the specific technology involved. These particularly high frequency bands allow a particularly wide transmission channel, so as to achieve extremely fast connection speed, but there are many disadvantages.
“The only advantage about millimeter wave frequencies is that they are empty, so there is enough space,” Ray said
First, for basic physics reasons, compared with signals in the lower region of the RF spectrum, signals in the millimeter wave range do not travel too far at all, and they do not penetrate solid objects such as walls and windows. This means that a large number of access points need to be deployed to cover a given area, even within a building.
“It’s not ready for enterprise deployment yet,” Filkins said“ Now it is not strong, but it has great development prospects. “
Millimeter wave technology has existed for at least a decade. The unlicensed wireless world has long had the 802.11ad standard, which is essentially Wi Fi operating at millimeter wave frequencies. Both Qualcomm and Huawei have built devices operating in this range, but the limitations of this technology and the continuous drought of terminal devices that can actually take advantage of it mean that it has been on the sidelines.
Of course, this will not always be the case. The trend of wireless bandwidth demand shows that the demand for spectrum is so large that millimeter wave is needed to deal with it.
“The rest of the world will eventually use [millimeter wave], and they don’t use it now,” Ray said
But at present, especially considering the fact that adding millimeter wave antennas and modems to mobile phones and laptops will increase their unit cost by $20, ray said millimeter wave will still be a future technology.