This document summarizes a research talk on RadioVisor, a system for slicing radio access networks. It addresses the problems of dense wireless deployments and exponential traffic growth. RadioVisor uses an SDN approach to control radio resources across base stations. It introduces a "RadioVisor" controller that manages resource allocation for different network slices through a 3D resource grid. Slices can be defined and configured flexibly for attributes like operator, device type, or application. The RadioVisor aims to enable more efficient sharing of radio access networks among different operators and traffic types.

3. RadioVisor
A Slicing Plane for Radio Access Networks
ONS 2014 Research Track
Li Erran Li (Bell Labs)
Joint work with Sachin Katti (Stanford)

4. Carrier’s Dilemma
2
0
2
4
6
8
10
12
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
0.0 0.0 0.1 0.2 0.5 0.9
1.6
2.8
4.7
7.4
11.2
Exabyte
Annual Growth 83%
0
2
4
6
8
-15
-12.5
-10
-5
-2.5
0
2.5
5
7.5
10
12.5
15
17.5
20
Shannon
Shannon (3dB)
4G
Exponential Traffic Growth Limited Capacity Gain
• Poor wireless connectivity if left unaddressed

5. Dense and Chaotic Deployments
• Dense: high SNR per user leads to higher capacity
o Small cells, femto cells, repeaters, etc
3

6. Problems
• Current LTE distributed control plane is ill-suited
o Hard to manage inter-cell interference
o Hard to optimize for variable load of cells
• Dense deployment is costly
o Need to share cost among operators
o Maintain direct control of radio resources
o Lacking in current 3gpp RAN sharing standards
4

7. SoftRAN: SDN Approach to RAN
BS1
BS2
BS3
BS4
BS5
PHY & MAC
Control Algo
Coordination :
X2 Interface
5
PHY & MAC
Control Algo
PHY & MAC
Control Algo
PHY & MAC
Control Algo
PHY & MAC
Control Algo

8. SoftRAN: SDN Approach to RAN
RE1
RE2
RE3
RE4
RE5
Network OS
Control Algo Operator Inputs
PHY & MAC
6
RadioVisor
PHY & MAC
PHY & MAC
PHY & MAC
PHY & MAC
Radio Element (RE)

9. RadioVisor Design
• Slice manager
o Slice configuration, creation,
modification, deletion and multi-
slice operations
• Traffic to slice mapping at
RadioVisor and radio elements
• 3D resource grid allocation and
isolation
o Considers traffic demand,
interference graph and policy
7
RadioVisor
Slice
Manager
3D Resource Grid
Allocation &
Isolation
Traffic to Slice
Mapping

10. Slice Manager
• Slice definition
o Predicates on operator, device, subscriber, app attributes
o A slice can be all M2M traffic of operator 1
• Slice configuration at data plane and control plane
o PHY and scheduler: narrow band PHY for M2M slice
o Interference management algorithm
• Slice algebra to support flexible slice operations
o Slice merge, split, (un)nest, duplicate
8

11. Resource Grid Allocation and Isolation
• Slices present resource
demands every time window
• Max min fair allocation
• Example
o Red slice entitles 2/3 and
demands 2/3 RE1 only
o Blue slice entitles 1/3 and
demand 1/3 RE2 and 1 RE3
Radio
Element 1
Radio
Element 2
Radio
Element 3
Interference Edge
Frequency
9

12. Conclusion
• Deployment costs motivate RAN Sharing
• We present the design of RadioVisor
o Enables direct control of per slice radio resources
o Configures per slice PHY and MAC, and
interference management algorithm
o Supports flexible slice definitions and operations

13. Questions?
Thank You!
Email: erranlli@research.bell-labs.com
11