Cooperative Water Filling (CoopWF) Algorithm for Small Cell Networks

1. Cooperative Water Filling (CoopWF) Algorithm
for Small Cell Networks
International Conference on ICT Convergence 2013
Toha Ardi Nugraha, Soo Young Shin
Department of IT Convergence, Kumoh National Institute of Technology

2. This paper proposes a new power allocation algorithm with
pre-coding in cooperative small cell networks (SCNs). A
power allocation algorithm based on cooperative water-
filling (CoopWF) is proposed and block diagonalization (BD)
precoding is adopted to cancel the inter-user interferences.
The proposed scheme is easily implementable to SCNs such
as femto-cell, metro-cell, and pico-cell. Simulation results
show that the proposed CoopWF algorithm provides better
mean capacity compared to the existing power allocation
algorithm.
Abstract

3. • Small cell network (SCN) such as femto-cell, metro-cell or pico-cell is an
effective solution for increasing the capacity of wireless communication
systems especially in the indoor public areas.
• SCN is generally implemented via a optical fiber backbone and allows a
reliable fast exchange of information among SCNs
• In SCN, a cooperative communication can be easily implemented.
• Cooperative communication is an effective strategy to mitigate inter- cell
interference and also it can dramatically improve the system performance
Problem Statement

4. • A power allocation algorithm based on cooperative water-
filling (CoopWF) is proposed and block diagonalization (BD)
precoding is adopted
• This paper propose cooperative power allocation algorithm
with BD precoding for small cell networks.
• The proposed algorithm is implemented and simulated in the
multi-user MIMO (MU-MIMO) SCN to measure the mean
system capacity.
Objectives

5. • Cooperative communication can be represented by Multi-cell MIMO system model as
shown in Fig.1
• Several small cells having Nt transmit antennas and uj user equipment's (UEs) having
Nr receive antennas.
• The two users are randomly located within the overlapping of the cell edge zone (see
Fig.1) with the radius of each small cell (R) is 20 meter.
• The indoor path-loss, for a small cell is modeled as a modified COST-231 indoor
propagation model.
• The received signal at the uj UE is given by
• The received signal for the user uj after BD is
Cooperative Water Filling

6. The paper evaluate the performance of
the cooperative small cells with the
number of C = 2 and 3 as shown in Fig.1
The number of antennas at each small cell as
transmitter Nt = 2 and each user device as
receiver is equipped with Nr = 2 antennas.
Small Cell Network
Architectures

7. When SNR is 0 dB, the mean
capacity of our propose
algorithm with C=3 cells
improved about 0.3 Mbps
compare to the previous
algorithm with the same
number of cooperative small
cell networks.
Simulation Result

8. This paper proposes a power allocation algorithm with block
diagonalization (BD) precoding in cooperative small cell networks.
The proposed scheme is easily implementable to small cell networks
such as femtocell, metro-cell, and pico-cell. In our simulation result,
we have shown that the proposed algorithm could improve mean
capacity. The simulation result is in line with the concept of water
filling that improved spectral efficiency on the low SNR. From the
simulation result, when SNR is -10 dB until 0 dB, the mean capacity of
our propose algorithm with C=3 cells increased about 0.4 Mbps
compare to the previous algorithm with C=3 cells.
Conclusion