Bengt Lindoff – BeammWave

Digital BF the scalable Antenna Technology!

Bengt Lindoff on September 21, 2022

Traditionally when designing analog or hybrid beamforming solutions for mmWave the design has been targeting a single application. A certain antenna panel/array has been designed for a certain purpose, such as a handheld device, and if another mmWave transceiver architecture is needed for another application that needs more antennae, such as a fixed wireless access point, or a small base station, another larger antenna panel has typically needed to be designed.

The 5G-NR mmWave communication devices range from a simple IoT device, via smartphones and fixed wireless access points, to devices for non-terrestrial communication as well as base stations. Designing different antenna panels with analog beamforming solutions for each of these use cases comes with a cost.

It would be an advantage to develop a scalable beamforming solution covering several of the use cases above, thereby reducing the development cost and enabling innovation of potential not-yet-known applications (possibly having almost unlimited bandwidth) as is the case in the mmWave radio spectrum.

Fortunately a digital beamforming architecture where one integrates the radio transceiver (RF) chip and antenna in a single encapsulation has this scaling possibility. The radio chip comprises the analog front end radio components, including down and upconverters, taking the mmWave radio signal from mmWave radio frequency down to an analog baseband signal on the receiver side and converting the transmitted analog baseband signal to mmWave radio signals on the transmitter side. The analog baseband signals have a bandwidth corresponding to the 5G-NR mmWave bandwidth and therefore are in the range of 100-400 MHz, those signals being easy to route on the PCB to a digital baseband processor.

The above integrated antenna and RF chip, when combined with digital beamforming algorithms that are implemented in the digital baseband processor, can be tailored to a flexible amount of antennae. Thus a scalable, low cost mmWave implementation for various use cases can be achieved by just applying as many RF chips as are needed for the particular use case. For instance, if we consider a mmWave IoT device that is only transmitting a small amount of data over short ranges, then it may only need two RF chips, plus associated SW that handles beamforming, to be configured for connection to two antennae to create such a device.

A more complex use case relates to a mmWave smartphone implementation. This needs to solve the challenges associated with handheld devices (these have been discussed in previous posts) and therefore need a distributed antenna architecture with, say, 8-16 Antennas and RF chips, with the corresponding digital beamforming algorithms adapted to that amount of antennae. Considering even more complexity, such as a Fixed Wireless Access Point, then 32-64 RF chips may be needed so as to achieve the desired data rate (several Gb/s).

The same set of mmW RF chips are reused for all types of devices. However, in order to meet any requirements for higher transmitting power and better receiver sensitivity, typical for more advanced use cases, then these are solved by adding more RF chips. The level of scaling can also continue to base stations, devices used for non-terrestrial communications such as drones and aeroplanes (requiring 100+ antennae) and to devices communicating with satellites (1000+ antennae). One can even imagine extending the scaling idea of digital beamforming radio architectures to inter-planetary and interstellar communication, where the number of antennae in these cases need to be in the range of hundreds of thousands to hundreds of millions of antennae. However, there might be some challenges with the 5G latency requirements in the communication that need to be solved as well

BeammWave develops a scalable digital beamforming architecture enabling the mmWave mass market on earth as well as in the sky.

Did you know that a person picks up the smartphone 250 times a day?

Bengt Lindoff on May 30, 2022

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.

*Performance simulation comparing analog beamforming with digital, picking up the phone and turning it 90 degrees*

In how many ways can you hold a smartphone?

Bengt Lindoff on May 23, 2022

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!