What about the future? What are the new applications? And can we really use this to communicate with exoplanets?
How can operators benefit from digital beamforming? What is the capacity gain and why does it work so much better?
Drilling into the hart of the matter for BeammWave! Digital beamforming – to-be-or-not-to-be?
Everything goes digital, why would beamforming be the only technology that does not?
What is mmWave and how do you do beamforming?
Wouldn’t 4G be enough for me? Is 5G just a hype to get me to upgrade and spend more?
The mmWave frequency range is highly suitable for sensing and radar purposes due to the short radio wavelength enabling localization and positioning in the mm to cm range. Joint sensing and communication is being discussed, where a communication system not only communicates but also senses the environment and basically uses mmWave radar for the detection and positioning of objects.
One of the key features of cellular communication is mobility – this allows a mobile terminal to move around between cells while maintaining an uninterrupted connection to the network. Mobility is important in mmWave communication too and particularly so if mmWave communication is to be successful in offloading traffic from increasingly loaded sub 6 GHz carrier frequencies.
Current radio architectures used in mobile terminals for 5G-NR mmWave communication rely on analog beamforming. In analog beamforming the mobile terminal can only transmit or receive in one direction at a time. Therefore, when searching for neighbouring cells, the mobile terminal is allowed to carry out beam sweeping in which it uses up to 8 different beams for detecting signals from every possible direction around it. This translates into the neighbour cell detection time being up to 8 times longer than if the mobile terminal had been capable of receiving from multiple directions at the same time. The same principle applies to signal strength measurements on beams in the serving cell i.e. the mobile terminal is granted additional time for carrying out beam sweeping. Analog beamforming thus results in a less responsive system, where handover or beam change may take a longer time than desired and therefore may lead to reduced end-user experience (end-user throughput, latency, power consumption) and overall system performance (system throughput, capacity). Additionally, it may lead to the mobile terminal dropping the mmWave connection and falling back to sub 6 GHz where capacity is scarce.
In contrast, digital beamforming allows the mobile terminal to receive from any direction without first having to conduct beam sweeping, and further, to receive from more than one direction at a time, if needed. Therefore, digital beamforming results in a far more responsive system than when analog beamforming is used, leading to better end-user experience and stronger overall system performance by the mobile terminal being connected to the best cell and the best beam at any given time.
BeammWave’s mobility algorithms utilise the above mentioned beam scanning and beam tracking advantages, along with a digital beamforming architecture, to thereby enable a robust mobility operation for mmWave communication.
5G, as well as previous generations of cellular communication, relies on standardized communication protocols for the interactions between mobile terminal and the base station. With new and evolved features, and support of higher data rates, the complexity of the standards has increased for each new generation of mobile communication.
Previous generations of cellular communication standards are using frequencies up to about 3 GHz, for which reliable communication can be maintained using one or a few omnidirectional antennas on the terminal side. With the introduction of NR frequency range 2 (24-71 GHz) (FR2), also known as mmWave, this is about to change as the radio propagation path loss at higher frequencies calls for beamforming based on multiple antenna elements to achieve sufficient sensitivity on both transmitter and receiver sides.
At a first glance it may seem that the requirements for beamforming in NR FR2 would only affect the radio front-end parts of the modem in a handheld device or the radio units in the base station, and by that only the radio frequency requirements of the 3GPP specifications. However, basically all aspects of the communication protocol for NR are affected when introducing mmWave communication.
The figure below shows a block scheme over the cellular modem part in a multi-RAT 5G-NR smartphone, supporting all communication generations from 2G to 5G. The modem can be partitioned into (1) radio components supporting the sub 6 GHz communication (i.e. all legacy communication 2G-4G and also the sub 6 GHz communication mode (FR1) in 5G), (2) radio components supporting the mmWave communication introduced in 5G-NR, and (3) a baseband processor performing all algorithms needed to process a received radio signal to an information signal in the receiver and generate a radio signal from the transmitted information signal in the transmitter. The figure also shows which parts of the radio blocks and baseband processor algorithms that need to be updated for mmWave communication, such as (with reference to respective 3GPP standardization document number)
- Radio frequency requirements (38.101-2)
- Demodulation performance requirements (38.101-4)
- Radio resource management (38.133)
- Physical channels and modulation (38.211)
- Physical layer procedures for control and data (38.213, 38.214)
- Physical layer measurements (38.215)
- Media access control (38.321)
- Radio resource control (38.331)
As can be seen mmWave communication is not only about radio design but it affects basically all algorithms and procedures in the modem, from the physical layer, up to the RRC layer .
Figure: a block scheme of a modem in a handheld device and corresponding parts affected by mmWave communication.
BeammWave understands all these aspects of the standard and how mmWave will impact the system design in handheld and fixed wireless devices, as well as in base stations, and will deliver a sustainable, scalable digital beamforming solution that enables the mass market for mmWave communication for 5G-NR.
Innovation is the strangest mix of slow and lightning fast. The slow part is all the tedious research done in labs and at universities, the hard (and slow work) of specifications, and the macro trends building persistently. These are all necessary enablers, but are for the most time not recognized as groundbreaking inventions, even if they sometimes render a Nobel Prize decades after they were done.
The missing part, and what we often perceive as the innovation that moves at the speed of light, is when the application is added on top of the new technology. This allows the full power of the underlying technology to be productive and generate a benefit for its users. The real trick here is to get the timing right and, as always, understanding the economic drivers and prerequisites for success.
If we focus on the use of mmWave in 5G, all the fundamental research and specification work has been done and we now have a VERY potent technology at our disposal. 5G has a few bold promises with “endless” capacity, “no” latency and “fiber like” speed. This enables innovations like remote surgery, remote control of different types of vehicles, industrial automation, virtual presence, etc.
BUT none of the above applications will be drivers of 5G. They will (almost) all happen once mmWave is widely deployed and available, but for none of them, on an individual basis, will it make financial sense to take the full, or even part, of a network investment. This is nothing new since it seems like every amazing and promising technology is always looking for the “killer app”, the one application that on its own can justify the wide deployment of the base technology. Once this is done and the technology is deployed, there will be an avalanche of innovative use cases and devices being built. I believe that many of us have been in the situation where we have tried to orchestrate a technology liftoff by trying to use the collective power of many different applications and, unfortunately, I believe there are almost as many of us who have failed, myself included. It simply seems to be a universal truth that a single killer app is needed.
This is probably also the explanation to the phenomena that so many have observed over and over again, namely that promising technologies always impact the market later than expected but once it happens the impact is way bigger than anyone would have dreamed of. It takes something to start an avalanche, but once started there is nothing stopping it!
So, what is the killer app for mmWave and 5G?
I will say…the smartphone!
But wait a minute, that was the killer app already for 4G! Yes, that is true … and your expectation of that killer app is an increased data bucket at a lower price. The operator needs a constantly lower price per bit sent and that is not possible without new technology and new frequency bands like mmWave. I also know that BeammWave’s digital beamforming solution will be one of the key enablers for making mmWave in 5G happen for the mass market.
Many believe the main reason for introducing communication in the mmWave frequency range (24 GHz and above) in 5G-NR is to allow for use cases requiring Gb/s such as VR or AR use cases. It is true that such use cases require a lot of bandwidth not existing in current sub 6 GHz frequency bands, and it is also true that 5G will be an unprecedented innovation platform for the coming decade, however the main driver is the need for more capacity in the radio spectrum.
Data consumption explosion over cellular is expected to grow exponentially and hence there will be a time, predicted to be around 2023 starting in Mega cities, where communication over the sub 6 GHz frequency bands start to reach its capacity limits.
The only way to support such data rate explosion in the world’s cellular networks is to utilize the mmWave frequency bands. In order to solve that, all wireless devices such as smartphones, both high end and low end, and even IoT devices, need in the near future to support communication in the mmWave frequency band. Therefore, mmWave communication, with all their challenges such as shorter coverage and high sensitivity for blocking radio signals by hands or other obstacles, need to be solved by a sustainable and scalable digital beamforming solution optimized from all angles of the system, not only focusing on the radio front end parts, which typically comes into one’s mind talking about mmWave radio communication, but also things such as:
– System architecture including radio and baseband interface
– Digital beamforming algorithms
– Mobility and handover procedures
– Performance and power consumption
BeammWave knows the entire system and delivers the digital beamforming architecture enabling the mass market for mmWave communication in handheld devices opening up the almost endless capacity existing in the mmWave frequency band!