5. Network Densification
Necessity to achieve desired capacity
First Step: Coverage (Macros)
Next Step: Capacity (HetNets)
Bring network closer to the user
More radio links, more antennas, higher spectral efficiency
LTE Advanced + HetNets -> Take capacity gains to the next level
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6. Network Densification (Contd…)
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
A tier-1 operator in Europe typically spends around 60% of revenue in OPEX. The burden will surely increase
with LTE and LTE-A
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7. Network Manageability
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
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8. The Backhaul Challenge
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
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9. User Device Challenge
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
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10. Interference Management
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
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11. WiFi and Offload Considerations
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
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13. Telco SDN – The Next Wave
Mobile Networks Then
Mobile Networks Now
SDN
A network of point-topoint 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
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
Source: Telco2.net
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15. Cloud RAN – Specific SDN use-case for the RAN
Cloud RAN – The first implementation of virtualization in RAN layer
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
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16. Cloud RAN – Architecture Possibilities
Active
Antenna
System
Centralized
Baseband
Bank
•2G/2.5 G
•UMTS
•HSPA
SON Server
•LTE eNB
•LTE-A
Common
Management
Server
IMS/
Operator Services
Optical
IP
Remote
Radio
Head
Internet
Coax
IP
Macro
Site
IP
Femto
Cells/
Wi-Fi
IP
Controllers
RAN SERVERS
on the
•GSM/GPRS
cloud
•UMTS
•UMTS Femto GW
•HeNBGW
•Wi Fi Access Gateway
Core Network
• 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
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17. Mobile and Cloud Infrastructure Convergence
RRHs
SDN Network Controller
Centralized BBU Pools
Core Network entity
Network Devices in SDN Terminology
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18. Aricent eNB IPR Readiness for C-RAN Solution
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 multicore 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.
OAM & SON
Client
RRM
RRC,S1-AP,X2-AP
Schedul
er
PDCP,
RLC,MA
C
GTPU
• Aricent Layer 2 can handle one cell/sector per
instance and multiple instances of Layer 2 can be
utilized to handle multiple cells/sectors.
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19. Cloud Ready Aricent EPC Framework
Router
eNodeBs
Top of Rack
Switch
Top of Rack
Switch
MMEs
HSS
SGWs
PCRFs
Subnet 1
Subnet 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
PGWs
ISP 2
EPC Frameworks
Cloud Enablers
Multi-tenant solution
Scalable deployments
EPC on virtualized environment
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20. Summary
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
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