To build the future digital world, the electromechanical interconnection of 5G systems is the key

To build the future digital world, the electromechanical interconnection of 5G systems is the key

5G elements seem to be ubiquitous, but the industry generally believes that the latest cellular networks are still several years away from reaching 4G/LTE penetration levels. This is in line with the historical trend of having a new network every 10 years, from which it is foreseeable that 6G systems will start appearing around 2030. It also makes everyone who is targeting 5G now “late early adopters,” a somewhat contradictory statement.

Author: Avnet

5G elements seem to be ubiquitous, but the industry generally believes that the latest cellular networks are still several years away from reaching 4G/LTE penetration levels. This is in line with the historical trend of having a new network every 10 years, from which it is foreseeable that 6G systems will start appearing around 2030. It also makes everyone who is targeting 5G now “late early adopters,” a somewhat contradictory statement.

Actually, this is a good thing. Early adopters are already there, but not yet to a mainstream-like level. Now is a good time to develop first-generation 5G solutions. Manufacturers can hope to develop several generations to span the decade before 6G begins to take over the market.

To build the future digital world, the electromechanical interconnection of 5G systems is the key

Any first-generation product is an ideal place to create great designs, forged by overcoming the challenges posed by new technologies. For 5G products, the main challenge and the biggest feature is performance. 5G is here and everything will be faster. Designers and system engineers will immediately understand that for them, being fast doesn’t always equal happiness.

Signal integrity is a big concern for any high frequency signal, whether it’s traveling through conductors or through air. All the advantages of 5G, such as highly dense traffic, more efficient spectrum utilization, greater bandwidth and lower latency, etc., need to be realized at every node in the network, including at the board level and between boards. between the components on these boards. This is where the 4-level Pulse Amplitude Modulation (PAM-4) scheme comes into play. It will support transfer rates of up to 56 Gbps and 112 Gbps, much higher than the non-return-to-zero (NRZ) modulation scheme being replaced. While NRZ will still be in use for a while, PAM-4 will enable 5G.

To build the future digital world, the electromechanical interconnection of 5G systems is the key
Key capabilities of 5G networks as defined in International Telecommunication Union Recommendation ITU-R M.2083 (Source: ETSI)

The European Telecommunications Standards Institute (ETSI) defines eight requirements that 5G systems must meet in terms of transmission rate, delay and efficiency. In addition, ETSI places more emphasis on three main application scenarios identified by the International Telecommunication Union Radiocommunication Sector (ITU-R): Enhanced Mobile Broadband (eMBB), Enhanced Machine Type Communications (eMTc) and Ultra-Reliable, Low-Latency Communications (URLLC) ). To meet the requirements of these application scenarios, the industry is leveraging new technologies and approaches such as mmWave transmission, smaller and more units, beamforming, and MIMO antenna technologies. MIMO technology increases the density of antennas in the transmitter, enabling antenna array densities as high as 256 elements.

From a device manufacturer’s perspective, this means that devices are physically smaller and more power efficient, but they handle more signal paths. These “physical connections” require extremely high signal integrity levels capable of supporting PAM-4 transfer rates. It is expected that 5G technology will be required in all vertical markets, mainly due to the low latency characteristics of 5G. These markets will require systems that can support high throughput at the component level.

The web is redefined

Part of why the move from 4G/LTE to 5G is so important is that it redefines network topology. Previous generations of products were built on legacy systems, continuing technology and methodologies. For 5G, these legacy systems can no longer be used. This can be seen in the new radio standard adopted by 5G. Virtually every aspect of the web has been redefined. Of course, it has to achieve this while still relying to some extent on existing technologies, such as RF connectors capable of carrying millimeter-wave signals.

The improvement of 5G openness has fundamentally changed the network structure. 4G’s Radio Access Network (RAN) consists of a baseband unit and remote radio heads. In the 5G architecture, this has evolved into a fronthaul network consisting of centralized units, distributed units, radio units and MIMO antennas.

This is where new remote radio units, active antenna units and baseband units are deployed. The fronthaul network will be connected to the core network, and the actual devices in the application scenarios outlined earlier will be connected through the fronthaul network using MIMO antennas.

While fiber-optic interconnects will be used in many places throughout the network, copper interconnects will still have an important role in the new 5G topology.

Mike Hansen, global product manager at Molex, explains that copper interconnect solutions are primarily used for routing between boards, and, interestingly, across boards as well. Using cable assemblies with twinaxes can avoid losses associated with PCB traces while enabling high-speed signal transmission.

According to Hansen, 5G has created a shift with the development of active antenna units (AAUs). These AAUs feature massive MIMO architectures and a lot of processing, all concentrated in a very small space. In the system architecture, high-density copper interconnects are essential.

Transmission of high-speed 5G signals

At the board level, the PCB is becoming a major obstacle to high-speed signals. While moving to fiber-optic interconnects can eliminate some of the pain points, at some point, electrical signals still need to be received through an integrated circuit interface. At this time, advanced interconnect solutions can provide higher signal integrity, as well as sensitive differential signals (Differential Signal) required lower insertion loss.

In addition to power, improved edge connectors provide the density needed to squeeze differential pairs and single-ended signals on a single, highly compact connector. This is achieved while avoiding signal integrity issues.

Instead of routing signals on crowded and lossy PCBs, signals are now routed from one side of the PCB to the other, or directly from I/O to integrated circuits, using components made from twinax cables . These so-called bypass cable assemblies avoid the losses associated with traditional PCBs and eliminate the need to enter and exit the optical domain, minimizing cost and latency.

To support the bandwidth involved in 5G networks, operators are using 56 Gbps PAM-4 signaling and, where possible, 112 Gbps PAM-4 signaling. Such high-speed signal transmission relies on fine impedance matching at the connector level. And that’s where Molex’s expertise lies. The internationally renowned connector manufacturer has an innovative NearStack high-speed cable solution that supports PAM-4 signaling.

As a Molex distributor, Avnet has been working with Molex for 40 years. The two sides trust each other and have established a very stable and strong cooperative relationship. With its extensive global network and extensive ecosystem, Avnet has long provided Molex’s leading connectivity solutions to customers in a variety of industries so they can meet market demands for faster, broader and more reliable connections .

More than that, Avnet has been deeply involved in the 5G field for a long time, and has a very comprehensive layout. It can provide complete solutions covering various application scenarios, accelerate the product design journey of OEM manufacturers, and help them quickly transform ideas into mature products. Bring to market.

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