Optical Transport Scenarios for Future Radio Access Networks

Optical Transport Scenarios For Future Radio Access Networks

Optical Transport Scenarios | Public | Ericsson AB 2015 | 2015-05-13 | Page 2

Radio scenarios: backhaul, fronthaul, CRAN, CPRI Optical transport scenarios: , SDN, Virtualization 5G, 50B, 1000x, 2020

Outline

Disclaimer: this presentation refers to research topics and its finalized to scientific dissemination in the context of PACE workshop. No product related information is contained in this presentation.


Radio Scenarios Backhaul, Fronthaul, CRAN, CPRI


RAN Deployment scenarios

Conventional Backhaul BB processing at each cell

BH

Backhaul: the transport network connection between the macro base station, the small cell or the centralized DU pool and the switch site (where the radio controller and/or the core network nodes are located).

Fronthaul: the transport network connection between the remote radio units and the baseband unit. The distance between RRUs and DU pool can be extended up to tens of km, where limitation is coming from processing and propagation delays.

DU RU

BH

DU RU

Local Fronthaul BB processing of small cells is done at macro cell

BH

RRU

RRU

RRU

RRU

RRU

RU

CRAN Centralized BB processing and geographical fronthaul

BH

DU POOL

RRU

RRU RRU

RRU

RRU RRU

RRU RRU

RRU RRU

RRU RRU

RRU

RRU

RRU

RRU


BH

DU POOL

RRU

RRU RRU

RRU

RRU RRU

RRU RRU

RRU RRU

RRU RRU

RRU

RRU

RRU

RRU

CRAN A Term with many meanings

CRAN is the term used to describe an architecture in which the baseband processing is centralized into one entity that is called DU pool or Baseband Hotel.

The letter C can be interpreted as: cloud, centralized (processing), cooperative radio, clean. No agreed definition. For Ericsson, C stands for Coordinated.

Usage of radio resources is optimized thanks to coordination. Treating digital resources as a single, grouped resource, allows

load sharing and balancing across the DU pool, offering high availability and seamless recovery.

DU resources are no longer dimensioned for peak requirements of each individual site, but for the aggregated requirement of the cell served by the pool, taking advantage of the distribution of the traffic over time and space.

CPRI CPRI

CPRI CPRI

CRAN Centralized BB processing and geographical fronthaul

CPRI Data transmission between RRUs and DU.


CPRI Common Public Radio Interface

CPRI is the radio interface protocol widely used for IQ data transmission between RRUs and DUs in CRAN scenario. One of the technical challenges for the CRAN architecture is the bandwidth required for CPRI data transmission. Other constraints are latency, symmetry, jitter. These comes from need to transport time synchronization signals.

Transport

Layer 1

Baseband

Layer 2 Control & Clock

SAPCM

SAPIQ

SAPS

Layer 1

Layer 2

SAPCM

SAPIQ

SAPS

Remote RF

Remote Radio Unit DU Pool

Fronthaul

Backhaul

LTE 20 MHz 2x2 MIMO 150 Mbps x sector

CPRI 2.5 Gbps


OPTICAL TRANSPORT Scenarios For the different RAN Architectures


Optical Transport Scenarios

Access Metro/Aggr. Core

Backhaul Segment

Access Ethernet Clients Up to 1 Gbps rate Up to 20 km Low cost High volumes W/copper areas Convergence

Metro/Aggregation Ethernet Clients 10 Gbps and more Up to 100 km Resiliency mandatory Flexibility and elasticity

Conventional Backhaul

Fronthaul Metro/Aggr. Core

Fronthaul Segment Residual Backhaul

DU POOL RRU

Metro/Aggregation CRAN has an impact on BH because the number of BH nodes is reduces (one or more levels of aggregation are skipped).

Fronthaul CPRI transport Maximum CPRI

rate is 10 Gbps Stringent latency

requirements limit distance

CPRI over optics

RRU

CRAN

RBS

DU RU

DU RU

ETH ETH CPRI ETH


Indoor Small Cell Indoor coverage Wi-Fi optional Office, restaurant

Outdoor Small Cell Outdoor coverage Roof, pole, lamp-post or wall mounted

Macro Cell Area

Coverage

In 1 Kmq of dense urban area: 29 Macro Cells, 200 m ISD 9 outdoor Small Cells x Macro for maximum gain 20-40% of buildings shall be integrated with indoor solutions with

up to 30% more gain with clever Wi-Fi installation

DU POOL

In 1 Kmq of dense urban area: Each Macro (LTE 20 MHz, 3 sect.): 2.5 Gbps CPRI flow -> 220 Gbps

- 1 ring, 24 @10G Each Outdoor Small (1 sect.): 2.5 Gbps flow -> 650 Gbps additional

- 4 ring, 24 @10G

RRU

RRU

RRU RRU

RRU

RRU

RRU RRU

Fronthaul

Bandwidth Requirements EXAMPLE: Dense Urban Scenario


SDN EXAMPLE: Cooperative Multipoint (CoMP) Accomplish Downlink Cooperative Multipoint (DL CoMP) from multiple cell sites to a single User Equipment (UE)

CENTRAL OFFICE

UE X2

Fixed topology without hub switch at DU pool

DU1 and DU2, in charge of the respective cell sites, communicate over a logical point-to-point link (e.g. X2) and then transmit the same user data over parallel optical fronthaul links. The data is then delivered to the UE.

DL CoMP is performed using the computational resources of both DU1 and DU2.

Topology path

DU1

DU2 SD

N C

ontr

olle

d O

ptic

al S

witc

h

UE

Re-configurable topology and SDN controlled hub switch at DU pool

A new path can be created from DU1 to the second cell site through SDN-controlled optical/electrical switching, such that DL CoMP is performed using just the computational resources of DU1 releasing DU2.

Moreover, DU1 and DU2 can be interconnected directly through the SDN controlled switch, with inter-DU connectivity managed centrally by the SDN controller, reducing latency compared to distributed control and offloading the inter-DU interface.

CENTRAL OFFICE

SDN ORCHESTRATOR

DU1

DU2


Virtualization of various network functions, including the optical network, will enable the realization of a multitude of functionalities in a virtualized data centre environment, eliminating the need for specialized hardware.

Orchestrator

Radio Spectrum

Availability

Optical Transport Network

Virtualization

Virtual

Digital Unit

Optical Transport Network Virtualization Systems

(servers)

Remote Radio Units

Virtual Resources

Physical Resources

Radio Resource Management

RRU VDU

Virtualization EXAMPLE: Virtual Digital Unit


5G meeting the expectations of the Networked Society


5G

2000 2010 2020 1990 2015

3G

4G

New wireless technologies

Wi-Fi

5G

GSM 5G =

evolution of existing standards

+ complementary

new technologies

Wide range of use cases Wide range of requirements


First 5G mobile Phone


5G Key Points

Massive growth in Connected Devices

Massive amount of communicating machines

50 billion connected devices

Massive growth in Traffic Volume

Further expansion of mobile broadband Additional users and increased usage

Additional traffic due to communicating machines

>1000x

Wide range of Requirements & Characteristics

Multi-Gbps in specific scenarios

Hundreds of Mbps generally available

Ultra-low latency

New requirements and characteristics due to communicating machines


Optical solutions for 5G will need to:

be programmable to support increasingly diverse service requirements for the wide range of applications envisioned in 5G

support higher capacities and an increasing number of cell sites

facilitate radio interference coordination between sites, by connecting RRUs with DUs with severe latency constraints

address cost and energy constraints by exploiting emerging optical components/devices enabled by integrated photonics

facilitate resource sharing among different network actors

be ready for the unexpected

Optical Transport Challenges

ITU Peak data rate User data rate Mobility Latency Traffic volume density Connection density Energy efficiency

METIS (EU Project) Experienced end user throughput Latency Energy efficiency Traffic volume density

NGNM Consistent user experience Device power consumption Coverage Resource efficiency Connectivity transparency Context awareness

Reliability, availability Security Mobility Cost efficiency Ease of deployment Operation efficiency

Wide Range of Requirements


Slide Number 1OutlineRadio ScenariosBackhaul, Fronthaul, CRAN, CPRIRANDeployment scenariosCRANA Term with many meaningsCPRICommon Public Radio InterfaceOPTICAL TRANSPORT ScenariosFor the different RAN ArchitecturesOptical Transport ScenariosBandwidth RequirementsEXAMPLE: Dense Urban ScenarioSDNEXAMPLE: Cooperative Multipoint (CoMP)VirtualizationEXAMPLE: Virtual Digital Unit5Gmeeting the expectations of the Networked SocietySlide Number 13First 5G mobile Phone5G Key PointsOptical Transport ChallengesSlide Number 17

Optical Transport Scenarios for Future Radio Access Networks

Technology

Transcript of Optical Transport Scenarios for Future Radio Access Networks