This document proposes a pathloss based power control technique to mitigate cross-tier interference between macro and femto cells in heterogeneous networks. It computes the distance and pathloss between macro and femto base stations, estimates the received signal power of the femto BS and SINR of macro user equipment under different transmit powers and locations. Results show that the SINR of macro UE increases when the femto BS transmit power is reduced and the distance from the femto BS increases. The technique aims to enhance QoS for macro UE while managing interference. Future work includes downlink interference mitigation and analysis considering femto BS pathloss models.

1. PATHLOSS BASED POWER CONTROLPATHLOSS BASED POWER CONTROL
TECHNIQUE IN HETEROGENEOUSTECHNIQUE IN HETEROGENEOUS
NETWORKNETWORK
AM.EzhilazhahiAM.Ezhilazhahi
Master of Engineering –Wireless TechnologiesMaster of Engineering –Wireless Technologies
Department of Electronics EngineeringDepartment of Electronics Engineering
Madras Institute of TechnologyMadras Institute of Technology
Anna University, Chennai-44Anna University, Chennai-44
05/22/17 1

2. RoadmapRoadmap
• Introduction to LTE-A
• Challenges in Hetnets
• Objective
• Literatures on Interference Mitigation Techniques
• Proposed work
• Results and Discussion
• Conclusion and Future Works
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3. • LTE-Advanced (LTE –A) release 10 is the upgraded version of LTE technology.
• Motivation of LTE-A :
• Spectral Efficiency
• Coverage
• QoS
Components of Hetnet :
INTRODUCTION TO LTE-AINTRODUCTION TO LTE-A
Type Coverage Range Deployment Mode
Macro Up to 30km Service provider defined
Micro Up to 2km Service provider defined
Pico Up to 200m Service provider defined
Femto Up to 10m User defined
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4. 05/22/17 4
ARCHITECTURE OF LTE-AARCHITECTURE OF LTE-A
MacroBS
Micro BS
Pico BS
Femto BS
CORE
NETWORK
INTERNET
Relay Node

5. CHALLENGES IN HETNETSCHALLENGES IN HETNETS
• Interference Management
• Co-Tier
• Cross Tier
• Load balancing
• Frequent handover
• Resource scheduling
05/22/17
Ying Loong Lee, Teong Chee Chuah and Jonathan Loo,and Alexey Vinel, “Recent Advances in Radio Resource Managementfor
Heterogeneous LTE/LTE-A Networks”, IEEE Communication Surveys & Tutorials, Vol. 16, No. 4, Fourth Quarter 2014, PP.No
2142- 2180. 5

6. 05/22/17 6
OBJECTIVEOBJECTIVE
• To mitigate the cross-tier interference between Macro and Femto Cell.
• Enhance the QoS of Macro User equipment.

7. INTERFERENCE MITIGATION TECHNIQUESINTERFERENCE MITIGATION TECHNIQUES
Cross-tier interference mitigation techniques
• Frequency scheduling
• Cooperative approaches
• Distributed learning
• Cognitive radio
• Power control
05/22/17
Ying Loong Lee, Teong Chee Chuah and Jonathan Loo,and Alexey Vinel, “Recent Advances in Radio Resource Managementfor
Heterogeneous LTE/LTE-A Networks”, IEEE Communication Surveys & Tutorials, Vol. 16, No. 4, Fourth Quarter 2014, PP.No 2142-
2180.
7

8. 05/22/17 8
Literature SurveyLiterature Survey

9. 05/22/17 9
S.N
O
TITLE CONFERENCE/
JOURNAL/
YEAR
OBJECTIVE METHODOLOGY
AND RESULT
1 Dynamic partial path-
loss compensation-
based power control
technique in LTE-A
femtocell networks
Journal of theoretical
and applied
information technology
, January 2016
Objective:
Reduce the outage probability of (MUE),
while maintaining good QoS for the home
user equipment (HUE)
Methodology:
The femtocell adjusts its transmit power,
based on HUE measurement report to achieve
the target.
Result:
Reduced the outage probability for the
MUEs.
Sawsan Ali Saad, Mahamod Ismail and Rosdiadee Nordin, “Dynamic partial path-loss compensation based power control technique in LTE-A
femtocellnetworks” , Journal of theoretical and applied information technology, 20th January 2016. vol.83. no.2, PP.No 303-312.

10. 10
S.N
O
TITLE CONFERENCE/
JOURNAL/
YEAR
OBJECTIVE METHODOLOGY
AND RESULT
2 Analyzing of power
control technique in
LTE advanced‐
Femtocell network
Journal of Scientific
Research and
Development ,2016
Objective:
Enhance the performance of handover.
Methodology:
Fractional Uplink Power Control (FPC) and
Adaptive Uplink Power Control (APC)
technique
Result:
Analyzed the correlation between SINR
and pathloss with respect to varying
pathloss compensation factor (α).
05/22/17 10
Azita Laily Yusof , Zairul Azren Mohd. Kamarul Zaman, Ainnur Eiza Azhar, Norsuzila Ya’acob and Azlina Idris, “Analyzing of power
control technique in LTE advanced Femtocell network”,Journal of Scientific Research and Development 3 (2): 98-105, 2016, PP.No 98-‐
105.

11. 05/22/17 11
S.N
O
TITLE CONFERENCE/
JOURNAL/
YEAR
OBJECTIVE METHODOLOGY
AND RESULT
3 Implementation of
Distributed Power
Control /Active Link
Protection for Femto
Cell Networks
Indian Journal of
Science and
Technology, Vol 8
(34), December 2015
Objective:
To improve performance of femto cells.
Methodology:
An optimized power algorithm
Distributive Power Control with Active
Link Protection (DPC /ALP).
Result:
The power utilized by DPC/ALP
algorithm is low which in turn optimize the
interference level.
Sreevardhan Cheerla, D. Venkata Ratnam, M. Siva Ganga Prasad, B. Vyshanvi and A. Sai Nitin, “Implementation of Distributed
Power Control /Active Link Protection for Femto Cell Networks” Indian Journal of Science and Technology, Vol 8(34), December
2015, PP.No 1- 5.

12. 05/22/17 12
LIMITATIONSLIMITATIONS
• A central controller is needed for assigning the values of compensation
factor and they have not focused on downlink interference mitigation.
• Adjusting transmit power of HeNB based on HUE measurement report
dose not consider about QoS of MUE.
• As the number of controlling signals are increased it is a time consuming
process.
• Pathloss model considered for analysis is based on the eNb and it has not
considered about the HeNB.

13. 05/22/17 13
PROPOSED WORKPROPOSED WORK
Pathloss based power control technique to mitigate the cross tier interference.
05/22/17 13
Computation
of distance
between the
MBS and FBS
Computation of
pathloss
between the
MBS and FBS
Computation
of RSRP of the
HeNB
Estimation of
SINR of MUE

14. 05/22/17 14
PROPOSED SCENARIOPROPOSED SCENARIO

15. 05/22/17 15
COMPUTATION OF DISTANCE BETWEEN THE MBS AND FBSCOMPUTATION OF DISTANCE BETWEEN THE MBS AND FBS
COMPUTATION OF PATHLOSS BETWEEN THE MBS AND FBSCOMPUTATION OF PATHLOSS BETWEEN THE MBS AND FBS
PL(dB)= 128.1+37.6 log10(d*0.0001)+External wall penetration
05/22/17
Mazen Al Haddad and Magdy Bayoumi, “Energy-Pivotal Solutions for Green Femtocell Power Control in Hybrid
DenseDeployments”, Center for Advanced Computer Studies, September 2016, PP.No 99-143. 15
The distance is calculated by using the following expression. Where
(x1,y1) and (x2,y2) are the location of the MBS and FBS respectively
2 2
2 1 2 1
( ) ( )D x x y y= − − −
Where,
d= distance between MBS and FBS.
Pathloss between UE and FBS is computed for both LOS and NLOS condition by using
the following expression

16. 05/22/17 16
(i) LOS(LINE-OF-SIGHT)(i) LOS(LINE-OF-SIGHT)
Where,
d = is the distance between the transmitter and receiver in [m].
fc= is the system frequency in [GHz].
A= includes the path loss exponent.
B= is the intercept.
C= describes the path loss dependence.
fc
PL(dB) A log10(d) B Clog10
5
 
= + +  
 
Mazen Al Haddad and Magdy Bayoumi, “Energy-Pivotal Solutions for Green Femtocell Power Control in Hybrid
DenseDeployments”, Center for Advanced Computer Studies, September 2016, PP.No 99-143.

17. 05/22/17 17
(ii) NLOS(NON-LINE-OF SIGHT)(ii) NLOS(NON-LINE-OF SIGHT)
Where,
X=5nw ; nw=no of walls between BS and UE.
fc
PL(dB) A log10(d) B Clog10 X
5
  
 
  
= + + +
VALUES OF LOS AND NLOSVALUES OF LOS AND NLOS
LOS NLOS
A=18.7 A=20
B=46.8 B=46.4
C=20 C=20
Athul Prasad, “Distributed Capacity Based Multi-Channel Allocation Algorithm for Local Area Networks”, thesis work from
Aalto University.

18. 05/22/17 18
COMPUTATION OF RSRP OF HENBCOMPUTATION OF RSRP OF HENB
Reference Signal Received Power (RSRP): computed with respect to received
interference power for Femto BS with respect to Macro BS:
RSRP=Ptx - PL(dB)
Where,
Ptx-Transmit power of the Macro BS
PL(dB)-Pathloss experienced by the Femto BS with respect to
Macro BS.

19. 05/22/17 19
ESTIMATION OF SINR OF UEESTIMATION OF SINR OF UE
The SINR of the Macro UE is estimated:
SINR= RHeNB
- { PHeNB
- PL(dMUE
) }
Where,
RHeNB
= Received power of the FemtoBS from Macro BS.
PHeNB
=Transmit power of the Femto BS.
dMUE
=distance between MacroUE and HeNB.
Sueng Jae Bae, YoungMin Kwon, Mi-Young Lee, Bon Tae Koo and Min Young Chung, “Femtocell interference analysis based on
the development of system-level LTE simulator”, EURASIP Journal on Wireless Communications and Networking 2012, PP.No 1-18.

20. 05/22/17 20
Results and DiscussionResults and Discussion

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PATH-LOSS EXPERIENCED BY FBS AT DIFFERENT LOCATIONSPATH-LOSS EXPERIENCED BY FBS AT DIFFERENT LOCATIONS

22. 05/22/17 22
PATH-LOSS EXPERIENCED BY MUE AT DIFFERENTPATH-LOSS EXPERIENCED BY MUE AT DIFFERENT
LOCATIONS WITHIN FEMTO CELL COVERAGELOCATIONS WITHIN FEMTO CELL COVERAGE
(i) When Femto BS is Near to Macro BS(i) When Femto BS is Near to Macro BS

23. 05/22/17 23
(ii) When Femto BS is at a moderate distance to Macro BS(ii) When Femto BS is at a moderate distance to Macro BS

24. 05/22/17 24
(iii) When Femto BS is at the edge of the Macro BS(iii) When Femto BS is at the edge of the Macro BS

25. 05/22/17 25
SINR EXPERIENCED BY MUE FOR DIFFERENTSINR EXPERIENCED BY MUE FOR DIFFERENT
TRANSMIT POWER OF HENBTRANSMIT POWER OF HENB
(i) When Femto BS is Near to Macro BS(i) When Femto BS is Near to Macro BS

26. 05/22/17 26
Contd…Contd…

27. 05/22/17 27
(ii) When Femto BS is at a moderate distance to Macro BS(ii) When Femto BS is at a moderate distance to Macro BS

28. 05/22/17 28
Contd…Contd…

29. 05/22/17 29
(iii) When Femto BS is at the edge of the Macro BS(iii) When Femto BS is at the edge of the Macro BS

30. 05/22/17 30
Contd…Contd…

31. 05/22/17 31
INFERENCEINFERENCE
• In LOS condition of MUE with respect to HeNB the received interference
power of MUE is more. Hence the SINR of MUE is low. Whereas, in NLOS
condition of MUE w.r.t HeNB the received interference power of MUE is
less . Hence the SINR of MUE is high.
• When the transmit power of HeNB is reduced the SINR of MUE is increased .
• When distance of MUE increases from the HeNB the SINR of MUE also
increases. Whereas, if the distance of MUE increases from the MBS the SINR
decreases.

32. 05/22/17 32
CONCLUSION AND FUTURE WORKSCONCLUSION AND FUTURE WORKS
• Cross-Tier interference mitigation provides a mean to increase the QoS of
Macro UE and also increase the network capacity.
• A pathloss based power control Technique is used to mitigate the cross-tier
interference. In which, transmit power is assigned by analyzing the path loss
with respect to location of the user and HeNB for both LOS and NLOS
condition.
• Hence, enhancement in QoS of both the Macro and Femto cell could be
achieved based on SINR and transmit power.
• This work can be further extended by considering co-tier interference, and
increasing the number of UE’s and number of Femto Base Station.

33. 1. Ying Loong Lee, Teong Chee Chuah and Jonathan Loo,and Alexey Vinel, “Recent
Advances in Radio Resource Managementfor Heterogeneous LTE/LTE-A
Networks”, IEEE Communication Surveys & Tutorials, Vol. 16, No. 4, Fourth
Quarter 2014, PP.No 2142- 2180.
2. Azita Laily Yusof , Zairul Azren Mohd. Kamarul Zaman, Ainnur Eiza Azhar,
Norsuzila Ya’acob and Azlina Idris, “Analyzing of power control technique in LTE‐
advanced Femtocell network” , published in Journal of Scientific Research and
Development 3 (2): 98-105, 2016, PP.No 98-105.
3. Sawsan Ali Saad, Mahamod Ismail and Rosdiadee Nordin, “Dynamic partial path-
loss compensation-based power control technique in LTE-A femtocellnetworks” ,
published in Journal of theoretical and applied information technology, 20th January
2016. vol.83. no.2, PP.No 303-312.
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05/22/17 33

34. 4. Sreevardhan Cheerla, D. Venkata Ratnam, M. Siva Ganga Prasad, B. Vyshanvi and
A. Sai Nitin, “Implementation of Distributed Power Control /Active Link Protection
for Femto Cell Networks” Indian Journal of Science and Technology, Vol 8(34),
December 2015, PP.No 1- 5.
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Chung, “Femtocell interference analysis based on the development of system-level
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05/22/17 34

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Local Area Networks”, thesis work from Aalto University.
Contd…Contd…
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