wireless communications research seminar 2012, february 16th on stochastic modeling ... ·...
TRANSCRIPT
On Stochastic Modeling and Analysis of
Femtocell Networks
Wireless Communications Research Seminar 2012, February 16th
Carlos Lima
LOCON - Local connectivity and cross layer design for future broadband mobile systems
Introduction (1/2)
Putting into context…
• Short-range communications provide better link quality and higher spectral efficiency [1, 2]
• Unplanned deployment and uncoordinated operation cause harsh Co-Channel Interference (CCI) [3]
• Self-configuration and (re)organization of femtocells
[1] H. Claussen, L. Ho, and L. Samuel, “An overview of the femtocell concept,” Bell Labs
Tech. Journal, vol. 13, no. 1, pp. 221–245, 2008.
[2] V. Chandrasekhar, J. G. Andrews, and A. Gatherer, “Femtocell networks: a survey,”
IEEE Commun. Mag., vol. 46, no. 9, pp. 59–67, Sep. 2008.
[3] D. Lopez-Perez, A. Valcarce, G. de la Roche, and J. Zhang, “OFDMA femtocells: A
roadmap on interference avoidance,” IEEE Commun. Mag., vol. 47, no. 9, pp. 41–48,
Jun. 2009.
Introduction (2/2)
Putting into context…
• Practical deployment scenarios
• Network dynamics and channel variations
• Characterize the received signal and CCI
distribution
• Analytical framework based on Stochastic
Geometry (SG) and Higher-Order
Statistics (HOS)
Stochastic Framework (1/4)
Stochastic Geometry: Key words [1]
• Poisson process with constant intensity
• Slivnyak’s Theorem and Palm probability
• Campbell Theorem
• Marking Theorem
[1] D. Stoyan, W. S. Kendall, and J. Mecke, Stochastic Geometry and Its
Applications, 2nd ed. Wiley-Blackwell, 1995
Stochastic Framework (2/4)
Higher Order Statistics
• Cumulants concept
• Properties (additivity)
Stochastic Framework (3/4)
Approximations
• There’s no general closed-form expression for the PDF of the sum of log-normal RVs
• Positively skewed
• Case study: LN, SLN Approximations
• Are there any other alternatives?
Stochastic Framework (4/4)
Performance Evaluation
• SIR interference limited scenarios
• Outage probability
• Average spectral efficiency
Case Study: CM (1/10)
System Model
• Path loss attenuation with large- and
small-scale fading
• Shadowed fading channel [1]
• MPP
[1] M.-J. Ho and G. L. Stuber,
“Capacity and power control for
CDMA microcells,” ACM Journal
on Wireless Networks, vol. 1, no.
3, pp. 355–363, Oct. 1995.
F B S 1
F B S 2
F B S 3
F B S 4
F U 1
F U 2
F U 3
F U 4
M B S
M U
t ag
ged
l i nk
Case Study: CM (2/10)
Solution Description
Detecting
Non-detecting
Tagged receiver
Case Study: CM (3/10)
Solution Description
• Detection event
• Coordination
regions
Case Study: CM (4/10)
Uncoordinated Scenarios
• Full Interference activity
Case Study: CM (5/10)
Uncoordinated Scenarios
• Full Interference + PC Transmit power
Case Study: CM (6/10)
Coordinated Scenarios
• PC with discrete power levels Detecting femtos
Case Study: CM (7/10)
Coordinated Scenarios
• Dynamic Exclusion Regions (DER)
Exclusion region
Case Study: CM (8/10)
Coordinated Scenarios
• DER + PC Exclusion region
Power control
Case Study: CM (9/10)
Approximation
m=16 m=2
Case Study: CM (10/10)
Numerical Results
What’s next?
• Large DAS Vs. Massive MIMO
• Traffic effect
• Area spectral efficiency
• Cluster process