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?
Wouldn’t 4G be enough for me? Is 5G just a hype to get me to upgrade and spend more?
We have in our previous posts shown the advantages with digital beamforming over analog beamforming from a performance point of view. Then one may ask; why hasn’t digital beamforming in mobile devices happened yet?
Well, if you ask people in the field, they will say that a digital approach has way to high power consumption due to the need of entire transceiver chain for all antennas whereas an analog approach only requires single transceiver chain due to that the beamforming is done in the analog domain at the front-end receiver using phase-shifters. Well, this might have been the truth in the past but let us check the case with the current state of the art technology.
Starting with the analog phase-shifters, which comprises switches and various physical routing of traces on the PCB used in order to make sure of coherent combining of the signal received or transmitted from the respective antenna. Passive phase shifters come with a loss of 8-10 dB to the already weak radio signal received by the antenna. That signal power loss needs to be compensated by a high gain Low Noise Amplifiers (LNA) on the receiver side and a high gain Power Amplifier (PA) design on the transmitter side. Such high gain high LNAs and PAs consume a significant part of the total power consumption in the radio receiver.
A digital beamforming architecture performs the combining in the digital domain and therefore the LNA and PA design can be more relaxed for digital architectures saving significant amounts of the power consumption.
Another important factor is that it is commonly believed that the analog-to digital and digital-to analog converters (ADC,DAC) need to be designed in the same way for both digital and analog beamforming, and since a digital beamforming requires an ADC/DAC pair for each antenna while the analog one only requires a single pair of ADC/DAC the power consumption must be N times larger for these components if N antennas is used. Furthermore, ADC/DAC has also in the past been a very power-hungry component and that (today erroneous) fact is still in many people’s mind in the field.
In fact, the power consumption for ADC/DACs especially when using 4-8 bits resolution, which is what is sufficient from a handheld device point of view, is nowadays, with evolving chip technology, on par with other radio components. Furthermore, which might at a first glance be a bit surprising, is that the number of bits needed for digital beamforming architectures can be reduced with 1 – 2 bits compared to an analog beamforming implementation due to the inherent converter quantization noise suppression made by combining the receiver streams after the ADC instead of before the converters as in the analog case! This relaxes the power consumption for the ADCs in digital beamforming solutions with 50-75% compared to the ADC needed for the analog solution!
By understanding and utilizing these facts together with a careful digital beamforming system design, BeammWave can deliver a sustainable and scalable digital beamforming solution with power consumption on par or better than current analog beamforming solutions for mobile devices! For further information please check out our white paper on The Power Efficient Architecture for 5G on mmWave Frequencies.
The smartphone is in your pocket or on the table. Suddenly you hear a buzzing sound, you pick up the phone and check the chat message you received on your device. On average, a person does this procedure 250 times a day according to a recent study!
This pick up the phone scenario is one of the trickiest situations to handle when using mmWave radio frequencies ; the communication between the mobile device and the base station is done using antenna arrays and beams. During the time you pick up the phone from the table (it takes roughly 0.5 seconds) the communication direction between the antennae in the smartphone and the base station changes a lot, thus in order to maintain the communication with the base station the processor in the device needs to perform beam-tracking.
In traditional mmWave radio system solutions using analog techniques, the beamforming (signal combining) is made in the analog domain close to the antennae, using phase shifters, and a combined signal is fed to the digital processor performing the beam-tracking. Since the processor only sees the combined signal, it needs to guess how to change the signal combining once it recognizes that the received signal strength has started to deteriorate. If the direction towards the base station changes very quickly, the beam tracking will always be lagging, with the result being that the device will not be able to receive the signal from the base station and hence not be able to transmit the signal in the right direction to the base station. Very low data rates (causing lagging), or even a dropped connection, is the result you will see on your smartphone.
Using a mmWave digital beamforming solution, the beamforming (signal combining) is performed in the digital processor after the digital processor has estimated the direction of the incoming signals. Using optimized beam-tracking algorithms, implemented in the processor, the signal can still be tracked even in this challenging scenario, and the performance will therefore not deteriorate as in the case using analog beamforming.
BeammWave has developed smart algorithms, optimised for a sustainable and scalable digital beamforming solution, thereby handling all kinds of challenging scenarios and minimizing the risk of lagging and performance degradation when the device operates using mmWave communication.
Did you know that people typically check their smartphones over 250 times per day? 80% check their phone when they wake up, 70% use their phone when in the restrooms and 40% look at their phone when driving despite it being illegal in most countries.
From such data one can understand that with more than 6.6 billion smartphone users in the world, looking on average 250 times a day on the smartphone, the way one can hold the phone may be a gigantic issue.
Regardless of whether you are standing, sitting, laying down or jumping you expect the device to have contact with the Internet so that you can use your favourite application whenever you desire.
For communication on radio frequencies below 6 GHz, i.e. the radio frequencies used in 3G and 4G today, a traditional antenna design with one or a few antennae, mainly at the top of the phone, is sufficient to handle all kinds of weird ways to hold a mobile device.
The introduction of communication in the mmWave radio frequency range in 5G, giving a tremendous increase of capacity in the network as well as enabling VR and AR applications requiring Gb/s data rates, comes with some challenges for smartphone applications. For instance, putting a finger on the antenna may drop the radio signal strength 100-1000 times (20-30 dB) so even a world class single antenna design placed at the top of the smartphone may not be sufficient. Also, if you are lying in your bed streaming your favourite series and having the phone in landscape mode, your hand will block the single antenna. Therefore you need a multi-antenna solution, not only to direct (beamform) your signal towards the base station, but also to have a sufficient number of antennae that are not blocked by your hand regardless of how you hold the smartphone!
Classical multi-antenna design for mmWave in handheld devices is based on distributing a number of antenna panels using analog beamforming in the phone. This is a very bulky solution, restricting the number of panels to 2 or 3 (placed at the top and on one or two of the sides). However, this will still not solve the hand blocking problem for all of the ways in which you can hold the smartphone, leading to a risk of a bad connection causing lagging or – even worse – a dropped connection.
To solve the problem, one needs a distributed antenna approach based on digital beamforming. Instead of having 2-3 antenna panels with 4 antennae, one needs 8-12 antennae distributed around the device with the capability to operate each antenna and radio transceiver independently of each other in order to combat the hand blocking problem.
Figure text: (A) shows a traditional mmWave solution for smartphones, with 3 antenna panels, each having 4 antennae. When the phone is in landscape mode, 2 out of 3 antenna panels are blocked giving bad signal quality in many directions (blue colour).
(B) shows BeammWave’s digital beamforming solution with 12 RF chips (i.e. 12 antennae) distributed around the phone. In landscape mode there will always be sufficient antennae which are free from hand blocking thereby giving good signal quality in all directions (red to green colour).
BeammWave understands all aspects of the mobile device challenges with mmWave communication and can deliver a sustainable, high performance, scalable digital beamforming solution that is optimised for handheld devices, thus making it possible to maintain a high speed connection to the Internet regardless of how you may want to hold your smartphone!