Munish Chhabra - Aricent November 2013
LTE-A Challenges and Evolving LTE Network Architecture Mobile and Cloud Infrastructure Convergence
LTE-Advanced and HetNets
Challenges
Evolving LTE Network Architectures
Summary
Agenda
2 Proprietary & Confidential. ©Aricent Group 2013
LTE A & HetNets
3
Challenges….
Necessity to achieve desired capacity
Bring network closer to the user
More radio links, more antennas, higher spectral efficiency
LTE Advanced + HetNets -> Take capacity gains to the next level
Network Densification
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First Step: Coverage (Macros) Next Step: Capacity (HetNets)
But, More Base Stations lead to … More Capex
• Equipment (baseband, radio, antennas) at each site
• Shelter, Air Conditioning, Battery at each site
• Backhaul – Connectivity with core network (cost vs performance)
Increased Opex
• More Rental and running cost
• More trained staff for network planning and maintenence
• More site visits for preventive and fault handling
• Energy Efficiency
• Significant part of OPEX
• Included Market, regulatory and customer requirements (especially for small cells)
Interoperability
Interworking nodes between different networks
Network Densification (Contd…)
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A tier-1 operator in Europe typically spends around 60% of revenue in OPEX. The burden will surely increase
with LTE and LTE-A
The number of network nodes go-up exponentially
Besides they co-exist with multiple other RATs
Extremely challenging to maintain and optimize such networks e.g.
• # Neighbor Relationships grow exponentially
• # Handover Relationships grow exponentially
• Coverage / Capacity trade-offs between different network layers
• Interference management becomes even more challenging
• Dynamic traffic patterns and low base station utilization
• Residential areas in the evening, Commercial during the day
Network Manageability
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Increasing radio network complexity casts its shadow on the backhaul
More base stations, more backhaul links
Base stations differ in terms of capacity, reach, transmission power and
radio access network technology, including 3G, “4G” and Wi-Fi
• Puts additional complexity burden on backhaul
ICIC and CoMP (Coordinated Multipoint) – Needed for better user
experience at cell edge
• ICIC – Coordination of spectrum allocation across multiple cells
• CoMP - Multiple base stations simultaneously serve a user device
• Needed - Real time co-ordination between base stations
• Needed - Low latency on backhaul
Base station need sub-frame level co-ordination
• Clocks need to be in phase
• Common reference needed from backhaul
The Backhaul Challenge
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Carrier Aggregation
UE to handle multiple simultaneous transcievers
Contiguous and non-contiguous carriers may be aggregated
Challenging radio environment
MIMO
Up to 8 transmitters in DL
MIMO increases the number of system antennas
Design of
• Radio antennas supporting Multiband and MIMO
• In the tiny space on a UE
• Becomes extremely challengig
Battery life of devices
User Device Challenge
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Higher base station density, more Interference
Randomly distributed
• Difficult to control and maintain coverage area, tilt, power and placement of
small form factor base stations
Particularly difficult to optimize Cell Edge users performance
• Terminal assigned to macro, sees strong interference from micro
• Especially if micro serves a CSG and the UE is not allowed to latch on to it
Interference Management
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Almost ubiquitous availability of WiFi (especially indoors in homes and
offices) mandates it for operators to consider offload
Offload however comes with its own challenges that have no answer in
the specifications yet
• Pre-mature WiFi selection
• Improper choices
• Degraded QoS after movement to WiFi
• Managing Trusted/Non-trusted networks
• Ping-pong problem
WiFi and Offload Considerations
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Evolving LTE Network Architectures
SDN would mean Network virtualization - Implementing more in software and using commoditized IT hardware
Programmability - The ability to centrally change traffic flows, partition the networks and
provide application-level QoS.
Separation of control and data plane
Telco SDN – The Next Wave
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A network of point-to-
point connections
A programmable fabric that can be
manipulated in real time to meet the
needs of the applications and systems
that sit on top of it
Mobile Networks Now
SDN
Mobile Networks Then
Source: Telco2.net
SDN Example
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Ref: Flexerasoftware.com
Separates the computing intensive baseband processing from the remote
radio deployments
Baseband processing is pooled at a semi-centralized location
C-RAN Enables
• Use of commodity HW to run baseband processing tasks
• More fluid resource allocation.
• Enables new feature implementation like CoMP and eICIC
• Helps ease capacity crunch by placing radios closer to the user
Cloud RAN – Specific SDN use-case for the RAN
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Cloud RAN – The first implementation of virtualization in RAN layer
Cloud RAN – Architecture Possibilities
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Active
Antenna
System
Remote
Radio
Head
Macro
Site
Centralized
Baseband
Bank
•2G/2.5 G
•UMTS
•HSPA
•LTE eNB
•LTE-A
Femto
Cells/
Wi-Fi
SON Server
RAN SERVERS
•GSM/GPRS
•UMTS
•UMTS Femto GW
•HeNBGW
•Wi Fi Access Gateway
Core Network
Internet
• Services are provided through optimum access technology
• Resources and coverage of a geographical area can be changed
dynamically
• SON can be used to get information for providing the necessary
configuration
• Resources are aggregated and dynamically allocated
• Reconfigurable BSs and controllers to support multiple Radio Access
technologies
IMS/
Operator Services
Optical
Coax
Controllers
on the
cloud
IP IP
Common
Management
Server
IP IP
Mobile and Cloud Infrastructure Convergence
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Centralized BBU Pools
RRHs
Core Network entity
Network Devices in SDN Terminology
SDN Network Controller
ENodeB Framework
• RAN on the Cloud will need to cater to variable
capacity requirements and host multiple cells.
Aricent Layer 3 and Layer 2 including Scheduler,
MAC, RLC, PDCP, GTPU, are scalable for multi-
core architectures, supports multiple form-factors
(femto, pico,micro) and different capacity
requirements based on deployment.
• Single instance of Aricent Layer 3 can handle
multiple cells/sectors hosted on Cloud RAN
equipment and can interface with cells/sectors
hosted on other Cloud RAN equipment on X2
link.
• Aricent Layer 2 can handle one cell/sector per
instance and multiple instances of Layer 2 can be
utilized to handle multiple cells/sectors.
Aricent eNB IPR Readiness for C-RAN Solution
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PDCP,
RLC,MA
C
Schedul
er GTPU
RRC,S1-AP,X2-AP
OAM & SON
Client RRM
Cloud Ready Aricent EPC Framework
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EPC Frameworks
Multi-tenant solution
Scalable deployments
EPC on virtualized environment
Cloud Enablers
Router
Top of Rack
Switch
Top of Rack
Switch
eNodeBs
MMEs SGWs
PGWs
HSS PCRFs
Subnet 2
ISP 2
Integrated software offerings for MME,
Serving GW, PDN GW, HSS and
PCRF nodes for OEMs developing
cloud EPC solutions – running in
clusters across virtualized hardware
with separated routing tables Subnet 1
The promise of SDN and C-RAN: Mobile and Cloud Infrastructure Convergence
Significant improvements in the manageability and flexibility of the network
Prevent the networks from becoming prohibitively expensive to deploy
Easy scalability
Helps in the addition of new services without the need to add more hardware
Easier for operators to exploit revenue opportunities
Meet time-to-market challenges
Helps reduce CAPEX and OPEX needs
Ability to tailor the network "on demand" to customer needs
Automated traffic management
Improved bandwidth engineering
SDN and C-RAN are the helping hands that will help LTE realize its true potential
Summary
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Confidentiality
•This material contains information that is confidential and proprietary to Aricent.
•Recipient may not distribute, copy, print or repeat information in the document
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21 Proprietary & Confidential. ©Aricent Group 2013