Beamforming and Massive MIMO in 5G Technology

The Shift from mmWave to Sub-6 in IoT Deployments 

5G networks will carve new paths for mobile. It will tap into previously unusable frequencies at the high end of the radio frequency (RF) spectrum (FR2). Earlier wireless standards could not operate in these higher bands. However, 5G solves the problem of overcrowding at the middle and lower frequencies (FR1).

At first, operators leveraged millimeter wave (mmWave) and thousands of miniature base stations called small cells. These enabled 5G to operate at frequencies up to 300 GHz compared to bands below 6 GHz used by current mobile standards.

However, operators realized how expensive it would be to deploy MIMO beamforming in IoT use cases (including the distance and line of sight limitations). They shifted their focus to the mid-band spectrum, spending billions of dollars to acquire it.

The mid-band or C-band spectrum auction was crucial for closing the gap between the low spectrum and the ultrahigh (and more expensive) mmWave spectrum.

mmWave is appropriate in densely populated and high-capacity areas. It’s also suitable for premium smartphones. Still, it is not ideal for:

• Large IoT deployments
• Enterprise networking
• SD-WAN
• Areas requiring fixed wireless access (FWA)

Sub-6 GHz is more cost-efficient for these scenarios. It does not require manufacturers to insert special mmWave active array antennas into an IoT device. Getting a mmWave capable device certified by the Federal Communications Commission (FCC) is an involved process. 

A New Network Structure

5G requires a new network structure to enable more targeted bandwidth use. However, it will require innovative technologies to compensate for:

• The propagation loss at higher frequencies
• The massive number of new users and devices 5G will connect

Two technologies, beamforming and massive MIMO, help direct and amplify signals, reducing interference and traffic jams. Analog, digital and hybrid beamforming are like traffic-signaling systems that conduct wireless signals in the right direction.

Beamforming and massive MIMO increase network capacity and improve performance. These technologies are ideal for densely populated, high-capacity areas (e.g., airports and stadiums) with many wireless devices. They prevent these locations from running out of network resources.

Beamforming and massive MIMO have also increased the network capacity in zones where the network infrastructure (e.g., small cells or mmWave antennas and base stations) are close to the receiver. This means the line of sight is available, and no obstructions inhibit transmission. 

In addition, the latest industry advancements in antenna technology, chipsets and software continue to enhance massive MIMO and beamforming. For example, electronic manufacturing, silicon processing and electronics miniaturization allow antennas to be packed into compact form factors. As a result, even small, battery-constrained devices can perform tremendous processing without overheating or exhausting their battery life. 

The Role of Beamforming in 5G Networks

Cellular signals, especially those carried by millimeter waves, can be blocked by objects easily and weaken over longer distances. Beamforming shapes signals and turns them into concentrated beams aimed at the receiver or bounced off obstacles like a billiard ball. Sending signals in several directions at once increases signal loss. Instead, beamforming applies relative amplitude and phase shifts to antenna elements to cancel out interference and create streamlined signal paths.

Beamforming applies processing to signals at the transmission end. In analog beamforming, those signals are summed up and receive analog-to-digital conversion (ADC) at the receiving end. In digital beamforming, amplitude and phase variation are reversed at reception by ADC and digital down converters (DDC). Beamforming transceivers are integrated into massive MIMO arrays at the device and cell site.

Massive MIMO employs these advanced beamforming techniques. It enhances the performance of wireless communication systems like 5G networks.

According to a report from Signals Research Group, T-Mobile’s 5G multi-user MIMO increased network capacity by 50%. Many telecommunications equipment manufacturers today have incorporated massive MIMO technology into their 5G infrastructure. This enables user-specific data channel beamforming, which boosts throughput and capacity. Massive MIMO solutions are pivotal in meeting network requirements for 5G mid-band deployments. 

Streamlining Complex Systems with Massive MIMO

Massive MIMO is like a traffic routing system that multiplies available network connections by a factor of 20 or more. Since higher band signals can use smaller antennas, many mmWave antenna elements can fit into a fingernail-sized pad on the device side.

4G base stations have around a dozen antenna ports, whereas 5G base stations have around a hundred antennas directing cell signals. Beamforming separates those signals and keeps them from interfering with each other.

Smaller base stations with more ports mean more transceivers can replace one transceiver on a typical cell tower. One array can have up to 64 transmitters and 64 receivers (hence the word “massive”). Among other processes, maximum ratio filtering can maximize the signal-to-noise ratio to amplify signals in dense urban areas. 

Massive MIMO arrays increased LTE speeds and improved latency. However, massive MIMO and beamforming technologies work together to achieve 5G’s promised scale:

• IoT connectivity speeds in double-digit gigabits per second
• Almost instant data delivery with less than a millisecond of delay

Meet the Demands of the 5G Era with Telit Cinterion 

Telit Cinterion’s certified 5G data cards address today’s high bandwidth mobile broadband projects. 5G technology enables carrier-grade broadband performance from mobile networks. Telit Cinterion offers evaluation kits to help you test hardware, connectivity services and device management.

Speak with our 5G IoT experts to get started on your IoT journey.

Editor’s Note: This blog was originally published on 5 June 2020 and has since been updated.