Post on 15-Mar-2020
FP7 ICT-SOCRATES
Load balancing in interaction with handover
optimisationp
Presented by Andreas LobingerNokia Siemens Networks
FP7 SOCRATES final workshopKarlsruhe, Germany
22 F b 201122 February 2011
Contributors: Irina Balan (IBBT), Thomas Jansen (TU BS), Szymon Stefanski (NSN)
Outline
Overview on Load Balancing (LB)(Deliverable 5.9: section 8.4)
Overview on Handover Parameter Optimization (HPO) Overview on Handover Parameter Optimization (HPO) (Deliverable 5.9: section 8.3)
LB + HPO integration, problem description LB + HPO, coordination approach
(D li bl 5 9 ti 9 1)(Deliverable 5.9: section 9.1)
Conclusions and future work
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
Load Balancing (LB)
General Idea: Shift load of a overloaded cell by forced handovers to surrounding low loaded cells t d i h i th l d diti f t k so act on dynamic changes in the load conditions of a network self optimisation.
SeNB TeNB
Control paramters:– Cell Individual Offsets for HO
What is load?
SeNB TeNB
Hysteresis h2
What is overload?y
Di t
LB HO offset
Hysteresish1
Distance
SeNB TeNB
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
LB, example result
Typical simulation scenarios contain an area of high load and some dynamic changes ( here moving the hotspot)
180
200
scenario 3
referencewith load balancing
1500
2000
2325
non-regular network; hotspot is moving from cell 27 to 13
Base Stationshotspot route
140
160
180
n ne
twor
k
500
1000
1500
4 5
81920
2223
24
2526
27
28
80
100
120104
atis
fied
user
s in
-500
0 1 2
3
6 78
9
101116
17
21
2829
30
[]
20
40
60
35
n un
sa
-1500
-100012 1314
15
18
3132
333435
0 200 400 600 800 1000 1200 1400 1600 18000
20
t [s]
-2000 -1500 -1000 -500 0 500 1000 1500
-2000 3336
X [m]
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
General idea: Gather information in the network about mobility
Handover Parameter Optimization (HPO)
General idea: Gather information in the network about mobility problems and control the handover parameters to reduce them. generate reasonable parameters for decent network performanceg p p Information as KPI (key performance indicators) of typical handover
problems – Radio Link Failure– Handover Failure
Pi P h d– Ping-Pong handover Parameters controlled
Hysteresis– Hysteresis– Time To Trigger
The effect of HO parameterpchanges
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
HPO, example results
Simulation scenarios: Regular Networks, all users the same speed
60
70
Handover failure ratioPingPong handover ratioRadio link failure ratio
1
ndov
er ra
tio
40
50
o [%
]
8
10
12
50
0.5
ing-
Pong
han
20
30
HPI
ratio
2
4
6
8
0.1
0.250.5
1
Hysteresis [dB]Time-to-Trigger [s]
P
100 200 300 400 500 600 700 800 900 10000
10
Hysteresis [dB]Time to Trigger [s] 100 200 300 400 500 600 700 800 900 1000Simulation Time [s]
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Approach: Run both algorithms in parallel and use a coordinator to
Integrated Use Case, LB + HPO
Approach: Run both algorithms in parallel and use a coordinator to limit the controls of the system. Note: Both algorithms use the HO decisiong
Interaction example:e ac o e a p e• Overload in SeNB shifts cell
border to point 2• Some user in the area
between point 1 and 2 will be handovered to TeNB ig
nal s
treng
th
handovered to TeNB• Increase of the Hysteresis in
TeNB can then shift the borderR
ecei
ved
s
TeNB can then shift the border to point 3 and increase the load in SeNB again
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
Integrated Use Case, LB + HPO
Coordinator approach following th f k f ththe framework of the SONcoordinator
– Coordination withCoordination with higher priority for HPO (COO1)C di ti ith– Coordination with higher priority for Load Balancing (COO2)
– Coordination mechanism to
mechanism to avoid abnormal situations (COO3)
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
Integrated Use Case LB + HPO, example results25
referenceHPO
6Ping-Pong Handover Ratio
15
20
ers
HPOLBLB + HPOLB + HPO + COO
2
4
[%]
10
15
Uns
atis
fied
Use
0 200 400 600 800 1000 12000
Handover Failure Ratio
5
2
3
4
[%]
0 200 400 600 800 1000 12000
t [s]
0 200 400 600 800 1000 12000
1
35
40unsatisfied usersHPIping pong
3
4
RLF Ratio
25
30
alue
ping-pong
HPIHO-failure
HPIRadio Link Failure
0 200 400 600 800 1000 12000
1
2
3
[%]
10
15
20
KP
I va
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0 200 400 600 800 1000 1200t [s]
reference HPO LB HPO + LB COO0
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
Conclusion and Outlook
In the HPO and LB use cases dedicated optimization algorithms were designed. Just putting them together can lead to additional old or new
problems. With a coordinator giving priority to one or the other algorithm With a coordinator giving priority to one or the other algorithm
already some problems can be resolved. A full coordinator also looking at interaction or abnormal behaviourA full coordinator also looking at interaction or abnormal behaviour
can lead to reasonable system performance.
Integration does not stop here … Still the details of a coordinator role or network function is ffs in
3GPP
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Andreas Lobinger, Nokia Siemens Networks, CTO Research
Thank you.
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Andreas Lobinger, Nokia Siemens Networks, CTO Research