The role of virtualisation in the dense wireless networks of the future Sokol Kosta CINI
Apr 01, 2015
The role of virtualisation in the dense wireless networks of the future
Sokol KostaCINI
Distributed Computing, Storage, and Radio Resource Allocation over Cooperative
Femtocells
3
Increasing demands in the wireless world
Want it all!Want it here!Want it now!
Can we enrich users experience with today’s terminals?
Well, it is all about apps…
Backhaul and wireless
4
Current elements in modernization of applications
According to CISCO
1. Make them accessible over the Internet on any device anywhere
2. Enhance performance, resilience and throughput
3. Use cloud computing for faster time-to-market, continuous development and change
4. Leverage open source components and open APIs
5. Develop and execute on infrastructure shared by multiple applications and users
TROPIC encompasses these targets and goes beyond…
5
Overall TROPIC objectives
TROPIC redefines architectures able to…
…virtualise/distribute applications close to user at empowered smallcell base stations
…enhance physical layer performance
Bringing computational power closer to users will entail
1. improving user experience, 2. prolong UE battery lifetime, and 3. potential revenue stream for operators
6
Small cell manager
The TROPIC scenario
7
Offloading to small cell eNB: pros and cons
Running apps in empowered small cell eNB instead of
external cloud
Running apps in empowered small cell eNB instead of UE
Small CellManager
+ Reduced latency
+ Reduce usage of backhaul
- Management of virtual machines
+ Computation speed
+ Reduced battery consumption
- Management of parallelization
- Increased PHY utilization Small cell manager (SCM) is needed to allocate computational resources
Technical scenarios
SCM serving single cell
SCM serving multiple cells
Coexistence of multiple SCM and cells
9
Small Cell Manager (SCM) provides offloading support to the UE, including computation/storage/radio resource management Best network architecture may differ among Mobile Network Operators (MNO), and may depend on the scenario (corporate, public, residential)
Network architecture needs to be enhanced
10
Joint management of radio and computational resources
0,1
maxi iUL P P DL
iL t s t
TLatency budget:
0,1, ,P UL DLs s s Bits processed, communicated
from/to UE,UL DLt t Time for UL and DL wireless tx
0,1
2 1 2 1UL DL
UL UL DL DL
i
UL DL
s s
W t W t
T UL P Pi DL Screeni
E t s t p LSNR SNR
EEnergy budget:
Parallel processing
Energy spent in UL
Energy spent in DL
Both convex problems with unique solution
, , , ,min
s.t. UL DL Pi UL DLt t s s s
E
L T
, , , ,min
s.t. UL DL Pi UL DLt t s s s
L
L
E
It is possible to plug an abstration of the PHY layer, for MIMO or even MU-MIMO channels
11
- Given latency and battery contraints, we can select a different operation point
- Each combination of application, processing architecture, and radio tx scheme will generate a different curve
5 10 15 20 25 30 350.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5Energy spent only by the UE
En
erg
y
Maximum Latency (s)
Optimization of the energy spent by the UE only
Optimization of the total energy
SNRDL=SNRUL = 20 dB
Energy vs. Latency Tradeoff
Example for virus scan application…
12
… in a multiuser scenario
UL Remotecomp.
resources
DL
.
.
.
.
.
.
.
.
.
UL schedulerComputation
schedulerDL scheduler
Assumptions:• Multiple users generate offloading petitions at a certain rate: • The offloading decision has already been taken for each UE involved• A certain probability of latency performance can be guaranteed
If multiple users are served by a single FAP, combine energy-latency resource allocation with scheduling policies.
Benefits and potential hurdles
13
Potential hurdles…
• Additional investment by MNO• Best network architecture may differ among MNO, and
may depend on the scenario (corporate, public, residential)
• Improving user experience,• Prolong UE battery lifetime, and• Potential revenue stream for operators
Benefits
Connectivity management for eneRgy Optimised Wireless Dense networks
Goal of CROWD
To enable sustainable deployment of very dense and heterogeneous wireless networks
sustainable = cost effective + energy efficientvery dense = 1000x compared to currentdensity (in users/sqm vs. users/BS)heterogeneous =
+ diverse range (macro vs. pico vs. femto)+ diverse technologies (LTE vs. WiFi)+ diverse deployments (planned vs. unplanned)+ diverse backhaul types (optical vs. wireless)
Research challenges
Very high density + heterogeneity =1. Interference in the radio access network2. Poor efficiency in the backhaul 3. High signalling for traffic management
InterferenceIssues with increasing density to grow capacity:• OPEX: limiting factor, no automated tool for HetNets• CAPEX: base stations are complex & expensive• Capacity does not scale with base station density!!
Some inter-cell cooperation tools are available• ABSF (LTE), OBSS (802.11) • Control tools needed CROWD Control architecture
Increasing number of eNBs provides an increasing of capacity up to a limit.
Indiscriminate increaseof network densityis not a viable solution
Backhaul
Increased capacity demand and density has to be sustained by the backhaul network, not only by the radio access network→ pitfall: costly overprovisioning of the backhaul network• CAPEX: expensive high capacity backhaul equipment• OPEX: increased cost and energy waste
Dynamic provisioning of backhaul resources is the key to an efficientbackhaul operation in very dense networks
Signalling
1. Technology-specific issues, e.g.:– 70% of air time (WLAN) occupied by management frames– Most of air time is taken by scanning processes
2. Mobility-related signaling critical:– Very frequent handovers, lots of subscribers– Reduce signaling over the air, Proxy approaches
CROWD Architecture
Logical view
Business view
The role of virtualisation in the dense wireless networks of the future
Sokol KostaCINI