Solution Brief
Mobile Network Operators
Radio Access Network

Silicom’s Intel®-based Palma
Ready for 5G Networks
Silicom’s Palma is a highly customizable Open RAN platform tailored for urban deployment.
Based on 3rd Gen Intel® Xeon® Scalable processors, it offers flexible acceleration
capabilities and a variety of synchronization options.
5G continues to gain traction around the world. According to a new report fromtechnology analyst PwC, 5G had achieved 75% coverage of the US in January 2021,
and the percentage will soon rise to 80%.
While the proportion of devices actually using 5G is considerably lower—just about
12% in July 2021 according to PwC—a tipping point is expected to arrive in 2023, withusage rates increasing strongly and steadily as customers reach the tech refresh pointin their mobile device upgrade cycles and mobile network operators (MNOs) solve their
5G deployment challenges.¹
This is desirable because 5G holds such great promise. 5G is needed to enable new
types of applications well beyond today’s voice communications and internet accessservices: powerful virtual and augmented reality applications that will only be practicalwhen the internet of things (IoT) becomes more responsive and reliable.
As such, MNOs are looking for more effective ways to implement 5G technology. Theywill have to make choices regarding how to configure the architecture, implement
virtualization, and manage their operations. For many MNOs, the right decision is tobuild out an Open RAN platform rather than to use a proprietary radio access network(RAN).
That is why Open RAN is gaining momentum. Open RAN is a series of standards managed
by the O-RAN Alliance and 3GPP that supports disaggregation, open APIs, and multivendor interoperability, all attractive features for MNOs seeking to build flexible,
responsive networks. It enables a new level of flexibility in network configuration, andsupports multi-vendor deployments, which is why an extensive ecosystem² of companies
and products are now designing for the Open RAN environment. In addition, the factthat Open RAN is designed for building virtualized RAN (vRAN) systems enables RAN
software to be run on commercial off-the-shelf (COTS) servers.
In previous cellular communications generations, RAN platforms included a baseband
unit installed on a powerful server at a central facility to handle signal processing andto communicate with individual remote radio units (RRUs) installed at or near the celltower. The RAN, including its RRUs, makes up the bulk of the cellular base station.
The Open RAN standard disaggregates the baseband unit into a centralized unit (CU)and one or more distributed units (DUs). The DU software handles real-time L1 and L2scheduling functions, while the CU is responsible for non-real-time L2 and L3 processing.
DU software can be installed on an Intel® architecture server at the cell site, or in an edge
cloud data center. The CU software is likely to be installed in a regional cloud data center.
Silicom, an Intel® Network Builders ecosystem partner, offers a ready-made DU hardware
platform called Palma, which is an Intel architecture-based, fully integrated DU platform,
designed for OpenRAN environments. The appliance has the processor performance,optional acceleration, memory, and precise time synchronization needed to support
even high-density DU deployments.
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Solution Brief | Silicom’s Intel®-based Palma Ready for 5G Networks

Figure 1. 5G RAN network design using Silicom Palma.

DU: The Basic Anatomy

Palma: 5G DU Hardware in a Box

While the CU manages high-layer functions, multiple DUs are
deployed in a network to support lower layers of the protocol
stack such as the radio link control (RLC) and medium access
control (MAC).

Palma is Silicom’s DU hardware platform for high-density
urban environments (see Figure 1). It is a companion productto Silicom’s Vigo. While Vigo provides four slots for optionalcards and runs on an Intel® Xeon® D processor, Palma provides
six card slots and runs on 3rd generation Intel Xeon Scalableprocessors, with 8 to 36 cores depending on the chosenconfiguration.

To maintain connectivity and throughput, the choice of the RAN
fronthaul interface is vital. This is usually a wired, but sometimes
a wireless, network with control systems that connect the CU
to the DUs, and the DUs to radio units (RUs), maintaining
throughput and reliability between other components of thenetwork.
5G networks are expected to require many more base stations
and antennas than 4G because they operate at higher
frequencies, which increases support for more devices but
attenuates the wavelength of a given antenna, thus reducing
its range. In cities, buildings and other structures can impede
signals, requiring MNOs to deploy small cells along city streets
and inside buildings to route signals around barriers.
The separation of the CU from the DU means that control
data flows need precise time synchronization—on the order ofmicroseconds or even nanoseconds—for coordination. Timesynchronization ensures that data packets can move from one
network element to the next smoothly and in the correct order.
Since the DU is a key to a fast, reliable network, MNOs mustchoose hardware wisely. It is possible to develop a customized
DU hardware platform by selecting servers, processors,accelerators, fronthaul interfaces, and software separately,
and then integrating them. This approach can enable someflexibility, but it is costly, time-consuming, requires significant
integration, and increases the risk of inefficient operation.

3rd generation Intel Xeon Scalable processors feature PCIe
Gen 4.0 connectivity, enhanced hardware-based security
features, and hardware-enhanced data service delivery. TheseCPUs deliver improvements in I/O, memory, storage, andnetwork technologies over previous generations.³
Several Intel technologies power key Palma security features,
including the Trusted Platform Module, which securely storeskeys, passwords, and digital certificates; hardware-based
encryption through Intel® Software Guard Extensions; a solidstate drive with integrated encryption; and built-in Intel®
QuickAssist Technology (Intel® QAT) cryptography accelerator
on the motherboard.
Palma features 12 fixed ports of 10/25 GbE using the Intel®
Ethernet Controller E810; support for additional networking
ports and different technologies is possible via Silicom’s
network adapter cards. Palma is designed to be installed inenvironments without climate control, with an operating range
from -4 to 135 degrees F (-20 to 55 degrees C). It is optimized
for edge computing services with a 1U and 2U-high rackmounted form factor with a front panel I/O interface for RU
connectivity.

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Solution Brief | Silicom’s Intel®-based Palma Ready for 5G Networks

Silicom Time Sync Solves Timing Issue
Precise synchronization timing is a significant technicalchallenge for 5G DU deployments. LTE networks, and even 5G
networks on a frequency-divided (FDD) spectrum, can survivea loss of synchronization that exceeds an hour. However, 5G on
a time division duplex (TDD) spectrum requires synchronizationon the order of microseconds to prevent interference. For carrier
aggregation and other use cases, the time synchronization
accuracy has to be within 65 nanoseconds.
Palma supports Silicom Time Sync Technology (STS) through its
I/O interface. Silicom STS is available in several configurations
utilizing the Intel Ethernet Controller E810. STS offers
Synchronous Ethernet (G.8261, G.8262) combined with IEEE
1588 precision time protocol (PTP). STS can serve as atransparent clock, boundary clock, and a grandmaster clock,accurate to the nanosecond level. It ensures synchronization
within the physical and protocol layers.

To augment the built-in processing power provided by the 3rdgeneration Intel Xeon Scalable processor, MNOs can deploy avariety of combinations of accelerator cards in the six card slotsthat can be augmented or revamped as needs change. Silicom
card options include:• Oakham Network Adapter: The Silicom Oakham Adapter
for 5G delivers high-performance and precise timesynchronization and is based on the Intel® FPGAProgrammable Acceleration Card N3000 utilizing Intel®
Arria® 10 FPGA combined with the unique Silicom TimeSync (STS) technology.

Silicom offers several STS-enabled adapters for Palma including
a 1/10 GbE card, a 10/25 GbE and a 25 GbE card.

• Lisbon ACC100 FEC network accelerator: The Lisbon
ACC100⁵ offloads forward error correction (FEC) processing
from the CPU, speeding up network throughput. The ACC100
is based on the Intel® eASIC™ N3XS device, a new class ofconfigurable integrated circuit (IC) that balances the fasttime-to-market of a field programmable gate array (FPGA)
with the power-efficient, purpose-built performance of acustom-developed application specific integrated circuit(ASIC).

RAN technologies and features rely on time sync levels ofvarious accuracies. For example, the deployment of coordinated
RAN features such as coordinated multi-point transmission(CoMP) requires a relative time sync of less than a microsecond
between radios.⁴

Silicom has tested Palma with FlexRAN for initial validation.
The company further tested the unit with leading 5G softwareand operating systems from leading vendors, including Red
Hat and VMWare. Palma is available now and ready for proofof-concept implementations.

Why Time Synchronization Matters
In 3G and 4G networks, the necessary time synchronization features were built into the circuit-switchedequipment on which they relied. Full packet-based voice and other real-time applications on 5G require
highly accurate packet synchronization.
Synchronization ensures data packets flow from one network element to the next at a fast, steadyrate and in the proper order. Packets can get out of order when they take alternate routes through thenetwork. Time sync ensures packet order so that communications are undistorted and accurate.

Solution Brief | Silicom’s Intel®-based Palma Ready for 5G Networks

Conclusion

Learn More

The fact that RAN functionality in MNO 5G networks has become
open and virtualized brings the potential for greater agility andlower costs, but the increased integration effort makes theselection of the right hardware platform—one that offers both
performance and customization—crucial. Silicom’s Palma, anOpen RAN platform based on open Intel technologies, is customdesigned to meet the real-time processing needs of 5G DUs. Witha 3rd generation Intel Xeon Scalable processor and six expansion
card slots, MNOs can configure Palma for a wide range of network
deployments, including urban locations that need processing
power for large groups of users. Silicom has designed Palma to
be the choice of MNOs seeking a cost-effective self-contained
server that bridges flexibility with simplicity.

Silicom Palma
Lisbon ACC100
Oakham FPGA Programmable Acceleration Card
Silicom Time Sync and Acceleration AdaptersIntel® Network Builders
Intel® Xeon® Scalable Processors
Intel eASIC devices
Intel® Arria® 10 GX Devices		Notices & Disclaimers¹ https://www.pwc.com/us/5g² https://www.o-ran.org/membership³ https://www.intel.com/content/www/us/en/products/docs/processors/xeon/3rd-gen-xeon-scalable-processors-brief.html
⁴ https://www.ericsson.com/en/blog/2019/8/what-you-need-to-know-about-timing-and-sync-in-5g-transport-networks
⁵ https://networkbuilders.intel.com/solutionslibrary/silicom-fec-acceleration-adapter-designed-for-4g-5g-networks		Intel technologies may require enabled hardware, software or service activation.		No product or component can be absolutely secure.		Your costs and results may vary.		Intel does not control or audit third-party data. You should consult other sources to evaluate accuracy.		© Intel Corporation. Intel, the Intel logo, and other Intel marks are trademarks of Intel Corporation or its subsidiaries. Other names and brands may be claimed as the property of others.		0821/DO/H09/PDF
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