Innovative technology drives rapid deployment of new 5G products, services and business models

The future of wireless is about developing the most compelling products using a combination of advanced technologies to maximize system performance, while optimizing both cost and power. This will unlock the rollout of new 5G products and services for mobile operators and the entire 5G ecosystem, from businesses to consumers to the economy. With 5G offering so much potential, how can the industry overcome cost, power and performance challenges to ensure the success of the second wave of 5G?

Any wise businessman knows how to protect his investments, the same goes for operators and their 4G investments. Existing 4G networks are made up of infrastructure such as cell phone towers and premises that house different parts of the radio access network, so operators are now exploring how they can leverage these investments by upgrading them. towards 5G. For example, high density locations, such as large urban areas, require additional radio capacity. With massive Multiple Input Multiple Output (mMIMO) panels forming the backbone of 5G radio deployments, operators can take their existing sites and upgrade them by replacing passive 4G panels with active 5G panels. Of course, installation should be easy and inexpensive, and the hardware should be as economical as possible.

Better cost optimization

There are several ways for operators to ensure that their 5G network infrastructure is cost-optimized. For example, the use of advanced silicon technology when upgrading existing 4G sites with 5G mMIMO panels means that original equipment manufacturers (OEMs) can design the systems best suited to their needs. unique. This ultimately means that the panels can be built according to specific cost requirements, as well as performance and bandwidth criteria. In terms of operating expenses (OPEX), power amplifiers (PAs) tend to dominate the power consumption of radio panels, so using the latest sound technology is extremely important. In addition, the form factor of the mMIMO panels should be similar to that of the existing 4G passive panels so that they can be replaced directly without increasing the rental of the site.

In a new attempt to help advance the deployment of 5G, operators have started to collaborate by sharing the costs associated with 5G equipment. Specifically, Vodafone and Telefónica in the UK have announced their intention to share cell tower and panel infrastructure. The two operators said the network sharing agreement would allow them to accelerate the deployment of 5G technology and reduce deployment costs. This is possible thanks to the 3GPP specifications, which allow operators to share 4G and 5G in the same radio, and the radios can be shared with multiple operators.

GaN technology for PA

In the deployment of 5G networks, energy consumption is another essential element that needs to be addressed. Today, PAs based on LDMOS (Side Diffusion Metal Oxide Semiconductor) technology dominate overall radio power consumption, with dissipation greater than 1 kW. It is therefore understandable that alternative technologies are now being explored. Specifically, gallium nitride (GaN) -based PAs have started to emerge and are already being deployed, which makes sense given that the properties of GaN-based technology exceed silicon-based LMDOS technology. existing in terms of bandwidth and power density requirements. In China, for example, GaN is now widely used due to its extremely energy efficient capabilities, especially at higher frequencies like 3.5 GHz. When using GaN, the overall power consumption of the PA can be greatly improved, which then has a ripple effect on the size, volume, weight and cost of the panel.

As GaN technology is non-linear, much more powerful digital predistortion (DPD) algorithms must be included to linearize the most energy efficient GaN PAs. Once the power consumption is adjusted, it is then possible to reduce the volume and weight of the heat sink. The heat sink is there primarily to remove heat from the RF section, so by reducing the power of the RF, the volume and weight of the unit can be reduced. The volume and weight of the unit determine the number of people in the crew and the equipment required to install these panels in the tower. The scale factor for the cost can be 2-3 times, depending on the volume, weight and number of people needed to install the panels.

Advanced silicon integration

Digital process automation (DPA) using GaN needs to be more powerful, and the ability to handle bandwidths of 400 MHz or more is crucial. Xilinx recently announced a new product, the Zynq RFSoC DFE, which has standard cell IP hard block functions for power and cost. The adaptive RFSoC platform integrates stronger IP than software logic, enabling a flexible solution that is high performance, energy efficient and cost effective. The device includes programmable logic that allows the user to customize and add their own algorithms, and optimize and upgrade their design as standards and bandwidth change. This adaptability and this capacity for sustainability are enormous advantages.

In addition, the enhanced DPD IP is based on Xilinx’s production-proven Soft-Core IP and enhanced to support advanced broadband GaN APs to improve power efficiency. In essence, this enables market agility as the 5G deployment experiences disruptive business models driven by interoperability initiatives (e.g. ORAN, TIP), new service providers and increased competition. The platform’s hardware adaptability enables innovation while providing the same benefits as an ASIC without NRE: reducing risk and overall total cost of ownership for new market entrants and traditional OEMs.

Fig. 1: Zynq RFSoC DFE block diagram.

Performance optimization

When it comes to Distributed Unit (DU), many operators are tied to proprietary systems offered by OEMs and have little control over the optimization of those systems. With the emergence of 5G, 3GPP makes it possible to completely virtualize the disaggregated base station, i.e. the distributed unit / central unit (DU / CU). A viable solution could be a standardized server approach, which runs open software that operators can control and optimize themselves for network performance and for 5G services. In terms of overall capacity gain, partitioning between the DU and the Radio Unit (RU) is critical to ensure that the 3-5X system capacity improvement is achieved. This is largely determined by the partitioning and architectural division between the functionality that goes in the DU and the functionality and the computer that is in the RU.

Uplink performance

Taking a deeper look at performance optimization, the right architectural split between baseband and radio is critical to achieving the performance promise. In the first wave of deployments, especially the uplink (UL), there were performance limitations and the expected bandwidth and capacity was not provided.

The performance of the beamformer in the UK is affected by several factors, such as the age and accuracy of beam weights. The limited beam weight frequency resolution also affects the uplink performance of the 5G system, as typically a single beam weight is shared between around 12 subcarriers. This is because the forward transport interface (FH) would be completely saturated if individual beam weights were applied to each subcarrier.

How do you meet these UL performance challenges? Implementing channel estimation based on reference symbols and calculating beam weights directly in the UK means that they can be applied directly to the beamformer, resulting in model updates. low latency channel and superior performance. This will also lead to improved beam weight frequency resolution with one beam weight for each subcarrier, again providing much better performance on the UL. However, additional calculation is required for this. Fortunately, the latest silicon technologies, such as the Xilinx Versal ACAPs, deliver exceptional compute density at low power consumption to perform the real-time, low-latency signal processing demanded by beamforming algorithms. AI motors, which are part of the Versal AI Core series, are ideal for implementing required math functions and offer high compute density, advanced connectivity, as well as the ability to be reprogrammed and reconfigured. ACAP devices also provide the additional capacity required to upgrade the harness formatter and add additional functionality even after deployment.

O-RAN virtualization

Finally, we cannot talk about the future of 5G without mentioning Open RAN (O-RAN). 5G operators are gradually moving away from traditional proprietary wireless devices in favor of an open, disaggregated DU / CU and RU approach, selecting different providers for DU / CU (O-DU & O-CU) and RU ( O-RU). By adopting the O-RAN architecture and specifications, operators can select a more innovative approach for every element of their O-RAN and benefit from reduced CAPEX / OPEX and lower total cost of ownership (TCO).

Whether it’s O-RANs or virtual baseband units (vBBUs), this “5G virtualization” carries the promise of software services deployed by telecom operators at the edge such as streaming demanding video, gaming or automotive services. With increasing investments in 5G infrastructure to support new, higher bandwidth services, greater system acceleration is needed to meet increasing scale and bandwidth demands. To solve this problem, Xilinx offers the T1 Telco Accelerator Card for Distributed O-RAN (O-DU) units and vBBUs in 5G networks. Xilinx Telco Accelerator cards offload high-throughput, latency-sensitive 5G baseband functions, freeing up telecommunications server processors for more interesting and commercialized software functions.

Fig. 2: Telco T1 accelerator card.

The future is adaptable

What does future 5G technology look like? Well, it definitely has to be adaptable. The first wave of 5G has given us a clear picture of the success metrics and challenges for the next waves, and it is evident that advanced silicon technology is a key element in realizing the 5G vision of higher capacity, power, cost and performance, as well as improved and innovative products and services, all in an economically viable way.