Ericsson | Embarking on the evolution to Packet Fronthaul

Embarkingon theevolution
to Packet
Fronthaul

1Ericsson | Embarking on the evolution to Packet FronthaulContent
1. Introduction...........................................................................................................................................................3
Background............................................................................................................................................................................................................................... 4
What is CPRI?........................................................................................................................................................................................................................... 4
2. RAN architecture ...................................................................................................................................................7
5G RAN Deployment architecture alternatives................................................................................................................................................................ 7
Ericsson Cloud RAN ................................................................................................................................................................................................................ 7

3. Deployment benefits and architecture considerations with Packet Fronthaul....................................8Transport architecture considerations............................................................................................................................................................................... 8
Synchronization in Packet Fronthaul................................................................................................................................................................................. 8
Latency....................................................................................................................................................................................................................................... 8
Quality of Service (QoS)......................................................................................................................................................................................................... 9
Availability................................................................................................................................................................................................................................ 9
Observability and O&M.......................................................................................................................................................................................................... 9

4. Handling of installed base of CPRI radios .................................................................................................. 10
Radio over Ethernet (RoE)...................................................................................................................................................................................................10
Conversion...............................................................................................................................................................................................................................10

5. Ericsson Packet Fronthaul solutions............................................................................................................. 11
Router 6673 with CPRI Line card.......................................................................................................................................................................................11
CPRI Line Card characteristics...........................................................................................................................................................................................11
Radio Gateways.....................................................................................................................................................................................................................12
Radio Gateway R608 and R308.........................................................................................................................................................................................12

6. Packet Fronthaul deployment scenarios..................................................................................................... 13
Packet Fronthaul in D-RAN networks..............................................................................................................................................................................13
Packet Fronthaul in C-RAN networks...............................................................................................................................................................................15
Packet Fronthaul in hybrid networks (mixed C-RAN and D-RAN)............................................................................................................................16
O&M solutions........................................................................................................................................................................................................................18

7. Conclusion ........................................................................................................................................................... 18
8. Resources............................................................................................................................................................. 19
9. Reference............................................................................................................................................................. 192

Ericsson | Embarking on the evolution to Packet Fronthaul

Introduction
Commercial 5G networks are going live around the world andEricsson technology is leading the way. With 5G come several newopportunities but also new ways to evolve networks. This paper
will explore the opportunities and the considerations that theevolution of the Fronthaul interface will create.
With the advent of NR, and the widespread deployment of Massive
MIMO radios with active antenna systems, Fronthaul technology
has evolved. This evolution is required to mitigate the otherwise
explosive bandwidth requirements on the digital Fronthaulinterface as a result of enhanced radio access technologies andadditional NR spectrum.
Since existing CPRI Fronthaul technology does not scale well withhigh antenna bandwidths and many antenna branches, Packet
Fronthaul was introduced by the CPRI forum. A new specification
was created, defining the evolution of CPRI, called eCPRI. This
specification defines the option to support functional splits
between the Radio unit and the Digital unit using Packet Fronthaul
technologies.
The functional split determines the Fronthaul bandwidth, while
radio features determine the latency requirements and the eCPRI
specification defines industry-standard transport technologies, e.g.
Ethernet and 1588v2 for synchronization. Using mature, standardtransport technologies reduces the cost of hardware components
and introduces the possibility of promoting a more flexible
relationship between the Radio unit and the Digital units.

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Ericsson | Embarking on the evolution to Packet Fronthaul

BackgroundThe concept of ‘Fronthaul’ was introduced with CPRI in 2003 when
an internal interface was specified for the new Main-remote building
practice where the Radio unit (radio frequency processing) was moved
from the base of the antenna mast to near the antenna (see Figure1). The Digital unit (radio control processing) stayed at the foot of themast. Moving parts of the processing to the top of the mast optimized

Antennaboth radio performance and site costs. The split between the Digitalunit and Radio unit is the division of the radio physical layer processing
and is referred to lower layer split (LLS) in a Radio Base Station(RBS). Evolved CPRI (eCPRI) was introduced in 2017 to address
new Fronthaul requirements introduced by NR and Active Antenna
Systems (AAS).

Antenna
Integrated
Radio (AIR)

Antenna

RU

Coax
cable
Antenna and RRU
combined

Remote Radio Unit
(RRU) in tower

thick coax
cable (RF)

Packetfronthaul(eCPRI)

Digitalfronthaul(CPRI)

RU
DU

DU

DU

2017

2003

1998

Figure 1: RBS evolution to today’s Fronthaul and CPRI/eCPRI

What is CPRI?
CPRI is standardized by the Common Public Radio Interface forum[1] , an industry wide initiative. The first specification was released
in 2003 and it covers user plane data, control plane transportmechanisms, and means for synchronization. CPRI does not mandate
a functional split between the Radio unit and the baseband processing
unit but does reference one radio functional split which is RF-PHY

HDLC

Ethernet

Layer 1

IQ
Data

Vendor Speciﬁc

Layer 2SYNC

Level of speciﬁcation

L1 Inband Protocol

Control &Management
Plane

User Plane

Well deﬁned in CPRI
• UMTS; CPRI V1 and V2• Wimax; CPRI V3• LTE; CPRI V4• GSM; CPRI V5

Time Division Multiplexing
ElectricalTransmission

OpticalTransmission

CPRI
Figure 2: Description of the CPRI interface [3](3GPP option 8). [2] The transport has a TDM structure with aconstant bit rate and scale with the number of antenna branches andsupported antenna bandwidth in the air. CPRI is suitable for point-topoint connections between the Radio unit and Digital unit, where theDigital unit is close to the antenna site.

Fully speciﬁed in CPRI
Informative only, except
clock rate

1Time Division Multiplexing
ElectricalTransmission

Fully speciﬁed in CPRI

OpticalTransmission

Informative only, except
clock rate

Ericsson | Embarking on the evolution to Packet Fronthaul

What is eCPRICPRI(evolved CPRI)?
eCPRI specification is Packet based and recommends (does notmandate) three different radio functional splits [3] the interface
could support. The functional splits determine the Fronthaul capacity
requirements and with what parameters the Fronthaul bandwidthscales. For some of these splits, the Fronthaul bandwidth scales withreal active user data. eCPRI gives the radio access network more
flexibility and, by leveraging industry-standard technologies like
Ethernet and 1588v2(PTP) synchronization, enables a reduction in
Fronthaul costs.

eCPRI Services
User
Data

Real-time
Control

other
eCPRI
services

C&M

eCPRI protocol layer

e.g.
SNMP

UDP

UDP. TCP.
SCTP. etc.

PTP

IP

VLAN (priority tag)

SyncE

ICMP

IPsec

Ethernet MAC

Connection
OAM

Synchronization

MACsecEthernet PHY

Ethernet
OAM

Figure 3: Description of the eCPRI interface [3]In summary, the eCPRI interface is a real-time traffic interface that uses a new LLS, using standard
technologies that have proved better bandwidth scalability and thus enable the use of sophisticatedcoordination algorithms to guarantee the best possible radio performance.

How can these technologies be deployed to achieve best TCO?
The illustration in figure 4 describes the different technologies (CPRI/eCPRI) and the different physicallayer splits within eCPRI for NR/LTE and deployment options. It shows a very flexible architecture withthe ability to support a wide range of deployment options. Packet Fronthaul enables the communications
service provider to deploy Radio processing for maximum benefit both for performance and TCO.

5

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Ericsson | Embarking on the evolution to Packet Fronthaul

Optimize performance and TCO e2e

100x
antenna sites

De-centralized

CPRI

De-centralized

eCPRI

Centralized

CPRI/
eCPRI conversion

CentralizedeCPRI

Optimize performance and TCO
across network deployments

1x hub sites

De-centralized

Cloud RAN

De-centralized

Digital front-end processing

Layer 2 processing

Beamforming processing

Packet processing function

Layer 1 processing

Radio control function

Figure 4: Flexible architecture to optimize TCO and performance

Benefits of Packet Fronthaul
Ericsson introduced eCPRI for the first time in 2017 and has since implemented eCPRI for Ericsson Massive
MIMO AAS TDD radios. Our experience with Packet Fronthaul has led to an all-Packet Fronthaul strategy
for the complete LTE/NR radio portfolio.
• The eCPRI interface enables up to a ten-fold reduction (depending on the functional split
between DU and RU) of the required bandwidth and in addition the required bandwidth canscale flexibly and proportionally with user plane traffic.
• eCPRI enables the efficient use of Packet-based transport technologies. Mainstream
technologies like Ethernet open the possibility to carry both eCPRI traffic and other traffic
simultaneously in the same Packet Fronthaul network. Packet Fronthaul also provides theability to automate the rehoming of Radio units, therefore decreasing OPEX.
• The interface is future proof, allowing new feature introductions by software updates of theradio network.
More information about the benefits of Packet Fronthaul can be found in Packet Fronthaul –design choices towards versatile RAN deployments white paper.

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Ericsson | Embarking on the evolution to Packet Fronthaul

RAN architecture
5G RAN Deployment architecture alternatives
The different types of possible architectures across the Ericsson RAN portfolio are described in Figure 5.
— Distributed RAN— Centralized RAN

Core NW

RAN
ComputeCloud
RAN CUCloud
RAN CUCloud
RAN DUCloud
RAN CUCPRIRadioRadio/
PacketGateway

eCPRI
Radio

Street
macro

CPRI
Radio

RAN
eCPRI
Compute Radio

Streetmacro

CloudRadio/RAN DU Packet
Gateway

CPRI
Radio

CPRI
Radio

Radio/ eCPRI
PacketRadio
Gateway

Figure 5: 5G RAN architectures

RAN traffic can be divided into different categories as seen in Figure
5. Fronthaul with CPRI or eCPRI for communication between theRadio unit and RAN Compute. RAN coordination traffic, Xn and E5,
for information exchange between RAN Compute units and Backhaul
traffic, NG, for communication between the RAN Compute and theCore network. F1 traffic is only applicable if the RAN Compute isseparated into a DU (Distributed Unit) and CU (Central Unit) function,
mainly applicable for Cloud RAN architectures.

The two main deployment architectures affecting Fronthaul are when
the baseband processing, called RAN Compute (L1 processing) is
distributed to each antenna site (Distributed RAN, D-RAN) or the RAN
Compute is centralized, and serving many antenna sites (Centralized
RAN, C-RAN).
Packet Fronthaul facilitates centralized RAN architectures by lowering
the transport deployment and maintenance costs using standard
technologies, but it is also suitable for Distributed RAN.

Ericsson Cloud RAN
Ericsson Cloud RAN supports both Distributed and Centralized RAN
architectures and uses generic hardware instead of purpose-built
hardware. It does this by using virtualization for parts of L1 and all of
L2 radio processing. Ericsson Cloud RAN architecture will support all

5G bands, including low-band, mid-band and high-band deployment
scenarios, through the Cloud RAN vCU and vDU, as shown in the figure
below.

For Cloud RAN to support
Ericsson CPRI based NR capableradios, Cloud RAN GW such as
R608 and Router 6673 with CPRI
LC can be used for converting
CPRI to eCPRI, see Ericsson
Packet Fronthaul solutions.

Figure 6: Cloud RAN supporting all 5G bands

Ericsson | Embarking on the evolution to Packet Fronthaul

Deployment benefits and architecture
considerations with Packet Fronthaul
Transport architecture considerations
The interface requirements are independent of deployment architecture (C-RAN or D-RAN) and are
dependent on the radio access technologies used: NR/LTE, TDD and FDD. For Packet Fronthaul, thetransport requirements can be different between LTE/NR and TDD/FDD due to differing RAN functional
distribution.
Capacity requirements for Fronthaul are dependent on antenna bandwidth, utilization of beamforming
technology, the number of layers in the air, radio access technology and baseband split option. In
comparison with backhaul capacity, the Fronthaul capacity requirement is higher. A good illustration of thisis the existing RAN Compute hardware, where there are 12 x 25GE interfaces for Fronthaul traffic and 1-2
25GE interfaces for backhaul.

Synchronization in Packet FronthaulWith the introduction of Packet Fronthaul, L1 time
operations have moved to the Radio unit enabling
precision timing protocol for synchronization of the airinterface. Ericsson eCPRI is using PTP over Ethernet
according to the ITU Telcom Profile for full timing
support 1588v2. For a more in-depth understanding
how synchronization plays an important role for new 5G
use cases and how transport solutions can be used to
distribute sync , please read the paper Synchronization
solutions in 5G transport network
TDD radio networks require a maximum time alignment
error between antennas in the radio network of
3 microsecond (+/- 1.5 microsecond relative to acommon time). This puts strict requirements on error
contribution allowed from the Packet Fronthaul network.
It is applicable for both NR and LTE TDD, but also for
coordination services such as Carrier Aggregation.
Some more advanced coordination functions used forco-located antennas/Radio units requires even tighter
time alignment.
FDD networks requires time alignment on network level
for the UEs to measure differences between neighboring
cells for handover. This is required for both NR and LTE
FDD networks.

Latency
A Fronthaul network need to be designed according to
the traffic with tough latency requirements. This will set
the size of a centralized network. In switched Packet
Fronthaul, latency will no longer be related only to fiber
lengths but also to the latency introduced by switching
and buffering. To maximize the serving area (the distance
between radio and baseband units) of hub sites in
Fronthaul networks, a combination of low-latency devices
and minimizing the use of buffers is needed for latencycritical traffic.

89

Ericsson | Embarking on the evolution to Packet FronthaulInterfaces

Transport technology

Latency RTT

CPRIConstant Bit Rate (TDM)

150µs

eCPRI

Variable Bit Rate (L2 Packet traffic)

150µs

E5(LTE)/E5(NR)

Variable Bit Rate (L2 Packet traffic)

120/900µs

F1

Variable Bit Rate (L3 Packet traffic)

10ms

NG/Xn

Variable Bit Rate (L3 Packet traffic)

10/30ms

S1/X2

Variable Bit Rate (L3 Packet traffic)

10/30ms

Figure 8: Latency requirement and transport technology for different interfaces

Quality of Service (QoS)
The main requirement for QoS schemes in the Packet Fronthauldomain is to safeguard the latency sensitive traffic such as eCPRI. By
applying QoS attributes, it’s possible to ensure that all types of traffic

can co-exist and achieve the characteristics needed to reach overall
optimal performance. Introduction of Packet Fronthaul enables theuse of standardized Packet functions for QoS and TSN profile A.

Availability
A Fronthaul architecture requires high degrees of availably to ensurehigh spectrum efficiency and low system downtime. Introducing
Packet Fronthaul enables usage of resiliency principles like TI-LFA
from the Packet domain to fulfill the availability requirement.
The recommended solution is to utilize a routed underlay formore centralized deployments to maximize the re-use of Packet
technologies. An additional benefit is that it enables a combinationof L2/L3 traffic over the same fiber. With L3VPN and EVPN type ofservices, it is possible to emulate a p2p link required for transportingeCPRI utilizing EVPN over a routed underlay such as MPLS-SR.
A more in-depth explanation of this topic is found in Packet Fronthaul– Design Choices Towards Versatile RAN Deployments under theheading “Packet Fronthaul Transport Network Architecture”.

Observability and O&M
To achieve good availability for a Fronthaul system, correlation
between the RAN and the Transport domains is recommended. A
degradation in the Transport domain will impact cell throughput
and degrade the end-user performance. Since these types ofdegradations can also be caused by issues in the RAN domain likeantenna failures, it is imperative to have the right level of visibility
for fault isolation and network performance monitoring acrossboth domains. A solution in this area requires automated discovery
of association/relation between RAN and Transport elements tocreate topology understanding, common KPIs between RAN andTransport for improved observability and fault consolidation for
quick troubleshooting. By utilizing a routed underlay, converged
provisioning of L2VPN (ex EVPN) and L3VPN, it is possible toenable the Fronthaul network to be used for other traffic types likebackhaul or enterprise services. The provisioning solution can befurther enhanced, by automatic creation of end-to-end RAN services
including the required transport service such as an EVPN.

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Ericsson | Embarking on the evolution to Packet Fronthaul

Handling of installed baseof CPRI radios
In all networks there will be a mix of CPRI and eCPRI radio solutions and to be able to capture all benefits
with a Packetized Fronthaul network there is a need to handle the installed base of CPRI radios.
There are two alternatives to handling CPRI radios in a Packetized network environment: Radio over
Ethernet (RoE), standardized as 1914.3, and CPRI to eCPRI Conversion. The main difference between
them is that the RoE keeps the CPRI stream and transports it over a Packet structure, whereas Conversion
terminates the CPRI stream and processes them to the eCPRI lower-layer split interface signals. Ericsson’s
recommendation is Conversion.

Radio over Ethernet (RoE)
RoE mapping can be done in the Transportdomain because CPRI data is not processed,
only transported. RoE mapping is doneby using standard Ethernet technologies
and is working in a similar way to Circuit
Emulation of TDM interfaces. Even thoughmapping is done in the Transport domain, it
still requires knowledge of the RAN as CPRI
implementations are RAN vendor specific.
The main drawback with RoE is that there isminimal bandwidth reduction in comparison
to native CPRI traffic. When there is nouser-plane traffic, it still consumes the same
bandwidth. CPRI is built on the assumptionthat upstream and downstream traffic
flow have the same latency. To achieve
this symmetry, the RoE systems needs tohave jitter buffers to handle variations andasymmetry in the Fronthaul network. The
jitter buffers introduce additional latency,
reducing the potential distance of the
Fronthaul network.
Since RoE is built around static CPRI
streams, it limits the ability to aggregate

and automate traffic flows. One can use
Ethernet to reduce the cost of WDM-optics,
but since RoE is a book-ended solution, notmuch else is improved in terms of reduced
capacity requirement and CAPEX reduction.
In addition, RoE can degrade sync accuracy
between Radio and Baseband since the sync
is transported inside the CPRI stream andcannot be corrected by the Packet network,
this may impact what RAN features can besupported by a RoE network.

• Encapsulate CPRI to Ethernet• Book-ended solution• Point-to-point configurations• Encapsulates the constant bitrate into Ethernet Packets• Can achieve up to 20% bandwidth saving with line code removal if enabled

Conversion
The most efficient method is to convert CPRI
into eCPRI within the RAN domain and thiscan be done by using an Ericsson Radio orFronthaul Gateway (see next chapter). Thisapproach leverages baseband processingof their CPRI data streams and convert thetime domain signal to frequency domain.
The benefit of the CPRI to eCPRI Conversion
is that it drastically reduces the capacity
required for Ethernet Fronthaul by scaling

traffic with used antenna bandwidth and by
removing the constant bit rate of the CPRI
traffic. Since the conversion is done in the
RAN domain, the conversion process will
not introduce any additional latency in the
Fronthaul network, enabling longer radiosite to CRAN hub site distanced compare to
RoE and greater flexibility in building the
Fronthaul network.

• Converts CPRI to eCPRI• Up to 60% to 80% bandwidth savings depending on radio configuration• Fewer fiber needed compared with RoE• Non-book-ended solution• Enable efficient Fronthaul networking

Combining CPRI to eCPRI conversion with
Packet aggregation at the antenna site is
the most efficient approach. The Fronthaulcapacity demands can be reduced by
60-80% depending on radio configuration,in comparison to other technologies such as
traditional CPRI or encapsulating of CPRI
with RoE.

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Ericsson | Embarking on the evolution to Packet Fronthaul

Ericsson Packet Fronthaul solutions
Ericsson’s portfolio is designed to allow flexible deployment scenarios need by service providers withsupport for both eCPRI and CPRI. Considerations of the needs of carrying different traffic types anddeployment in different physical locations are reflected in the flexible and modular platform. Ericsson’sradio portfolio strategy is to eventually offer Radio units that can support either eCPRI or CPRI. For Radio
units that cannot support eCPRI, Ericsson has two alternative solutions:• Radio over Ethernet (RoE)• CPRI to eCPRI conversion
Ericsson Packet Fronthaul offering includes three gateway productswith different capabilities, ensuring the best solution for each
deployment scenario and site requirement. With an Ericsson solution,
it is not only pre-verified but can visualize the end-to-end setup
from RAN Compute, Transport and Radio, including all intermediateconnections and their relationships. All alarms and KPI data arecollected in one management system, allowing for correlation andend-to-end visualization of network health and including mapping of
RAN traffic to corresponding Transport flows for easier fault isolation.
This solution can be complemented with automation schemes.
Deployment scenarios are described in the Packet Fronthaul
deployment scenarios and include Cloud RAN deployments.

Router 6673 with CPRI Line card
Ericsson Router 6673 is a Fronthaul gateway with embedded RAN Compute functionality using the unique
Ericsson Silicon solution. This enables efficient conversion to eCPRI for Ericsson RAN sites, and can also use
RoE to cater for older types of radios in the network.

Router 6673 characteristics
1.5 RU multiservice node
800 Gbps with 8 x 10/25GE and 4 x 100 GE ports
Three line-card slots, for 9 port CPRI line-card or Ethernet line cards
Support Class C sync, G.8275.1 and G.8275.2 T-BC with integrated T-GM with Ericsson GPS/GRU

CPRI Line Card characteristics

RoE Mode supports CPRI 2.5, 4.9, 9.8 & 10.1Gbps
Software upgradable to support CPRI 2.5, 4.9, 9.8 & 10.1Gbps Conversion to eCPRI

Ericsson | Embarking on the evolution to Packet FronthaulRadio Gateways

The Radio Gateway family is an evolution of the Baseband R503 CPRI mux/demux product. The new Radio
Gateways switches and converts multiple CPRI streams to one eCPRI 25GE stream. The Radio Gateways
are part of the gNode/eNodeB system and managed via the RAN Compute O&M interface.

Radio Gateway R608 and R308
There are two product variants: indoor 19” and an outdoor version that follows the RAN Compute outdoor
building practice.

Hardware characteristics:
12 ports CPRI (10G SFP+ 3W limit)• CPRI 3 (2.5Gbps), CPRI 5 (4.9Gbps), CPRI 7 (9.8Gbps) or CPRI 8 (10.1Gbps)
4 Ports eCPRI (25G SFP28)• eCPRI 25G (4 x SFP28)
Sync and LMT RJ45
R608: Indoor unit 1RU• Dimension: 442 x 267 x 44 mm (17.40 x 10.51 X 1.72 in)• Power: Dual DC
R308: Outdoor unit 15 liters (915.36 in3)
• Power: DC

12

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Ericsson | Embarking on the evolution to Packet Fronthaul

Packet Fronthaul deployment scenarios
Ericsson Radio System provides solutions for almost every network scenario and service provider needs.
Each product in the portfolio fits under at least one, and often two, of the three categories: Capacity,
Compact and Coverage. The 3Cs are therefore useful tools for quickly identifying which products fit therequirements of the customer’s network. Cloud RAN solution leverages general compute hardware tocompliment the Ericsson Radio System portfolio as it addresses additional deployment scenarios.

Figure 9: Ericsson Radio System

Packet Fronthaul in D-RAN networks
The illustration below depicts the following scenarios,• Radio Gateways acting as a port fan out for the RAN Compute by converting and multiplexing CPRI-eCPRI• Radio Gateway and Fronthaul gateway supporting CPRI radio connectivity to Cloud RAN vDU by
Conversion●.

ExtendBB●capabilities
ports to fully
utilize
processing

CPRI Radios
CPRI Radios
eCPRI Radios

R308/608
eCPRI

RAN Compute

Router 6673
RAN Compute

Macro site

eCPRI

Cloud
RAN DU

Cell site router
Macro site
eCPRI Radios

CPRI Radios

Router 6000

CPRI Radios

eCPRI RadioseCPRI

Cell site router

R308/608
Router 6673
MINI-LINK 6352 for eCPRI

Macro siteeCPRI

RAN Compute

Figure 10: Packet Fronthaul in D-RAN networks

To connect toMacro site toEricsson Cloud
RAN

Macro site

Cloud RAN DURAN Compute

Cloud
RAN CU

Ericsson | Embarking on the evolution to Packet Fronthaul

In the Coverage type of sites, Radio Gateway R608 is ideal as Ethernet
aggregation function is not needed. Radio Gateway R608 makes it
possible to fully utilize RAN Compute capacity as multiple radios canbe supported using a single eCPRI port on the RAN Compute node.
In Compact type of sites, such as street pole where space is limited,Radio Gateway R308, in combination with the all-outdoor RAN
Compute solution, can be used together to reduce the physicalfootprint needed.
In the Capacity type of sites, many CPRI Radios, 25GE eCPRI based
AAS and associated RAN Compute nodes exist in addition to possible
Enterprise traffic. Router 6673 can provide the Ethernet switchingconnectivity (eCPRI, E5, L2VPN/L3VPN) for these functions. Router14

6673 can also be used as part of the synchronization solution and cellsite router for the D-RAN site.
With the introduction of Cloud RAN, there is a need for Cloud RAN
Gateway to convert CPRI from existing CPRI radios to eCPRI. In
addition, Ericsson Spectrum Sharing (ESS) functionality will be placedon the Cloud RAN Gateway in this setup. This is because servers where
Cloud RAN is deployed will only have Ethernet interfaces and Ericsson
Cloud RAN only supports 5G. Radio Gateway 608 can be used for thisconversion and ESS function. In larger, Capacity-type of sites wheremore radios and Ethernet connectivity are needed, Router 6673 canprovide the same functionality at a higher scale for Cloud RAN. BothRadio Gateway and Fronthaul Gateway products are part of Ericsson
Cloud Gateway family

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Ericsson | Embarking on the evolution to Packet Fronthaul

Packet Fronthaul in C-RAN networks
In C-RAN type of deployments, Radio and RAN Compute functions
are typically physically located at different locations. Radios are
deployed at antenna sites with RAN Compute deployed at larger
C-RAN hub sites in a distance typically within 15km. A Packet
Fronthaul transport solution can be used to connect between andwithin the antenna and C-RAN hub sites.
Packet Fronthaul dimensioning for the C-RAN case will depend on
an operators’ traffic as stated earlier in the document. The Fronthaulbandwidth is determined by user bit rate and the RAN features thatdrive user bit rate. Depending on the traffic model conversion from
LTE/NR low band Ericsson CPRI to eCPRI radios will reduce the
Fronthaul bandwidth between 30 - 50% via Conversion. As eCPRI
is a variable bit rate technology (VBR) it also enables trunking gains
that can increase bandwidth savings further – a total of 60 - 80%. A
more in-depth explanation of this topic is found in Packet Fronthaul –design choices towards versatile RAN deployments white paper.

Hub Site

CPRI Radios eCPRI Radios

eCPRI/TN/Xn/E5/F1

eCPRI/NG/Enterprise

Router 6673

CV
CV
CC
VC
V

Router 6000

Antenna site

RAN Compute

Streetmacro

IP Network
CPRI Radios
TN/Enterprise (backhaul)

eCPRI

R608/308
Antenna site
Figure 11: Packet Fronthaul in C-RAN networks

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Ericsson | Embarking on the evolution to Packet Fronthaul

It may be desirable to convert CPRI to eCPRI at the antenna site to
optimize the connectivity from our new RAN Compute basebands
with high speed 25GE Fronthaul interfaces. For example, in a compact
antenna site, one Radio Gateway R308 could connect the site back to
RAN Compute at a hub location using one fiber per antenna site.
The Radio Gateway R308 and R608 products at the antenna site
can aggregate multiple CPRI radios onto a single 25GE eCPRI
connection toward RAN Compute at the hub site. For compact sites

with NR capable CPRI based Radios, R308 and R608 offers the lowest
footprint and most cost-effective solution.
For larger capacity radio sites with mix of legacy and NR capable
CPRI/eCPRI radios, Router 6673 offers the most flexible solution.
Router 6673 can aggregate multiple CPRI radios, eCPRI radiosand potential enterprise services traffic to a 100GE connection(alternatively to 100GE connections) towards a hub site, whileproviding feature rich synchronization and Packet functionalities.

Datacenter

CPRI Radios eCPRI Radios

RAN Compute
eCPRI/TN/Xn/E5/F1

eCPRI/F1/Enterprise

Router 6673

Router 6000

Antenna site

Streetmacro

CPRI Radios

eCPRI/TN/Xn/E5/F1

Cloud RAN

TN/Enterprise (backhaul)

IP Network

eCPRI

R608/308
Antenna site
Figure 12: Packet Fronthaul in C-RAN networks with Ericsson Cloud RAN

With C-RAN type of deployments, C-RAN hub sites can also serve as the location for edge compute. The
Ericsson Cloud RAN solution fits a deployment scenario where DU functionality runs over server-based
compute platforms. The Ericsson Packet Fronthaul solution with Cloud RAN and ERS Basebands allows toservice providers to seamlessly fit the different pieces together and work in concert. Service providers havethe flexibility to deploy, manage and adjust the solution as they migrate and evolve with 5G.

Packet Fronthaul in hybrid networks (mixed C-RAN and D-RAN)
We understand that actual deployment of 5G and choice of C-RAN vs D-RAN is not always straightforward.
With a Packet Fronthaul solution from Ericsson, we can accommodate different deployment scenarios
due to our solution flexibility. In the following example, an operator chooses to centralize newly deployed
5G only basebands for mid-band AAS and low-band FDD while leaving existing 4G/5G dual mode
ESS basebands at the macro site. Ericsson solution allows this flexibility by using inter-site advanced
coordination services with Packet Fronthaul solution transporting eCPRI, CPRI, E5 and backhaul traffic
across sites. In addition, Packet-based connectivity at the macro sites allows for integrating other siteequipment’s such as environmental monitoring solution via Ethernet.

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Ericsson | Embarking on the evolution to Packet Fronthaul

Re-purposed aggregation site

CPRI Radios CPRI/ eCPRI Radios

4G 5G ESS
RAN
Compute5G
RAN Compute

eCPRI/TN/Xn/E5/F1

TN/E5

Router 6673

Router 6000

Existing macro site

eCPRI/ X2/ Xn /S1/NG/E5/EnterpriseStreetmacro

TN /Enterprise(backhaul)

IP Network
CPRI Radios

eCPRI

R608/308
Antenna site
Figure 13: Packet Fronthaul in hybrid networks

4G RadiosRe-purposed aggregation site

CPRI/eCPRI Radios

4G
RAN
ComputeeCPRI/TN/Xn/E5/F1

TN/E5

Router 6673

eCPRI/ X2/ Xn /E5/F1/Enterprise

Router 6000

Macro site

5G
RAN Compute

StreetmacroeCPRI/TN/Xn/E5/F1

Cloud RANCPRI Radios

IP Network
TN/Enterprise (backhaul)

eCPRI

R608/308
Antenna site
Figure 14: Packet Fronthaul in hybrid networks with Ericsson Cloud RAN

Ericsson | Embarking on the evolution to Packet Fronthaul

On top of the flexibility shown, Ericsson Cloud RAN solution can be seamless deployed in the C-RAN hub
site for additional 5G capacity in this example. This is because the infrastructure needed to for Cloud RAN
to operate with the rest of the network is available with this transport network architecture. Cloud RAN
through this architecture will be able to interact with CPRI based radios at macro site, coordinate with RAN
Compute basebands, and communicate with 5G core.

O&M solutions
Ericsson Packet Fronthaul products are part of Ericsson Radio System utilizing a common management
system, Ericsson Network Manger (ENM). This enables alarm consolidation between RAN and Transportelements for improved fault isolation, e2e visualization and coordinated self-healing functions. An
example: cell degradation can be caused by issues in the transport domain or in the air interface. By
combining a set of KPIs from RAN and Transport like Packet loss, air interface performance and connection
status, the root-cause can be clearly visualized. This can be complemented with consolidated alarms,
constructed either rule based or by AI/Machine learning, pin-pointing the issue regardless if it is in the RAN
or Transport domains. ENM includes a solution for automatic provisioning on transport services on topof a routed underlay, with an evolution path to offer automatic end-to-end provisioning for RAN services
including setup of the transport infrastructure and by that simplifying reconfigurations and deployments.
Today we are providing this solution as part of our ENM offering and it can be used as an integrated
solution in ENM or through the supported north bound interfaces for integration with other management
systems and tools including Ericsson Intelligent Automation Platform.

Conclusion
Ericsson’s strategy is all Packet Fronthaul for the complete radio portfolio to ensure the most cost-effective
transport solution regardless of RAN architecture. As we migrate our radio portfolio from native CPRI
Fronthaul to eCPRI Packet Fronthaul we have solutions to convert the existing Ericsson CPRI interface
to Ericsson LLS eCPRI by moving baseband processing from the Digital unit to our new Radio Gateway,
Router 6673 CPRI line card products leveraging Ericsson Silicon.
With Ericsson’s Packet Fronthaul solutions, you have an efficient and flexible toolbox for all your different
deployments needs, that can also cater for continued network evolution. Using verified end-to-end
solutions and products managed with a common management system, you will make sure you have thebest performing networks and ease of use.

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Ericsson | Embarking on the evolution to Packet Fronthaul

Reference
1. www.cpri.info.
2. 3GPP specification series: 38series
3. http://www.cpri.info/downloads/eCPRI_Presentation_2017_08_30.pdf
4. Packet Fronthaul – design choices towards versatile RAN deployments
5. Synchronization in 5G transport

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