Fyp Presentation SEM1

FYP SEM 1 PRESENTATION

INTERFERENCE MITIGATION IN LTE/LTE-A NETWORKS

NAME: INDIRA KARIMOVA MATRIC NUMBER: KEW100701 SUPERVISOR:ASSOC PROF.DR. CHOW CHEE ONN

OBJECTIVES

• To study of performance of LTE-Advances networks with and

without using interference mitigation approaches.

• To compare the performance of the three major frequency

reuse schemes which are Integer Frequency Reuse(IFR),

Fractional Frequency Reuse(FFR) and Soft Frequency

Reuse(SFR) in macrocell and femtocell networks in LTE

• By using Matlab result is investigated in our result.

INTRODUCTION • This project focuses on the performance of interference

mitigation techniques in LTE/LTE-A networks with focus on

frequency reuse.

• MITIGATION TECHNIQUES WITH IFR,FFR,SFR.

• MACRO AND FEMTOCELL

The Concept of Femtocell

Femtocells – very small size, low power home base station that works with frequency bands and can improve the network coverage. Base Station-Uplink/Downlink

Interfering mobile terminal - same cell

Interfering mobile terminal- adjacent cell

Interference Mitigation

Conventional [Integer] Frequency Reuse

• Frequency Reuse 1 • Same frequency is reused by each

sector • High spectral efficiency • Large inter-cell interference • Cell edge users can rarely retain

connection

Frequency Reuse 3 Same frequency is reuse every 3 sectors Low spectral efficiency Low inter-cell interference Cell edge users have fairly good connection quality.

- Cell-edge band using frequency reuse 3, allocated to the cell edge users - Cell center band using frequency reuse 1, allocated to the users in the center of the cell

-Whole bandwidth can be reused in each cell in contrast to FFR. -Inner-uses all sub-bands with less power; - Outer-uses pre-served sub-bands with higher power; (orthogonal to each other) - The reserved band at each cell is allocated for center users with restricted power

SIMULATION PARAMETERS • The following table summarizes the network’s parameter’s values

during the simulation.

Parameter Value

Celcullar layout Single macrocell

Macrocell radius 250m

Femtocell radius 30m

Bandwidth 20MHz

Modulation Mode QAM64

Carrier frequency 2Ghz

Subcarriers spacing 15kHz

Noise power density 174dBm/Hz

Size of one cell 500m

Macro BS TX power 46dBm

Femto BS TX power 11dBm

Outdoor wall loss 20dB

Size of map 500m

Size of center zone 0.63 of macro coverage

Correlation distance 40m

SIMULATION SCENARIOS

• Scenario 1: Co-channel operation. The worst case of

cross-tier interference, where no frequency partition or

power control is applied and both femto - macrocells are

using the same spectrum.

• Scenario 2: Apply of IFR. When Integer/Incremental

Frequency Reuse of factor 3 is employed by Macro base-

station and femtocells measurements

• Scenario 3: Apply of Soft Frequency Reuse or Fractional

Frequency Reuse.

SIMULATION RESULTS FOR CASE 1 Case 1 is presented in Figure below where I have considered 10 femtocells, 10

femtocell users and 1 macrocell user. The Bandwidth is chosen as 20 Mhz and the

modulation as 64QAM.

Worst case scenario where no interference

mitigation control. Experiencing low SINR

as depicted by dim red color intensity

Macro-User’s data rate map for

instance of the interference during

configuration stages.

SIMULATION RESULTS FOR CASE 1

• COMPARISON => IFR < FFR < SFR

SFR

FFR

It improves greatly the cell-edge throughput

It also greatly improve cell-edge throughput except at the bottom left.

It significantly improves the overall system SINR and hence data rate.

IFR


• Case 2 is presented in Figure below where I have considered 12 femtocells, 12

femtocell users and 2 macrocell users. The Bandwidth is chosen as 20 Mhz and the



mitigation control. Experiencing low SINR

as depicted by dim red color intensity



configuration stages


• COMPARISON =>IFR<FFR<SFR

FFR

SFR

It improves greatly the cell-edge throughput.

IFR

Also slightly improve cell-edge throughput except at the bottom left. It significantly improves

the overall system SINR and hence data rate.


• Case 3 is presented in Figure below where I have considered 24 femtocells, 24

femtocell users and 1 macrocell user. The Bandwidth is chosen as 20 Mhz and the



mitigation control.



configuration stages


• COMPARISON =>IFR<FFR<SFR

FFR

SFR

No improvement (as power control) the overall system SINR and hence data rate.

Its also slightly improve cell-edge throughput bellow/above-side .

It improves slightly the cell-edge throughput .

IFR

RESULTS = IFR < SFR

IFR performs better in cell center.

The comparison is made between IFR and SFR schemes to test which scheme will perform better in improving cell-edge throughput.

BUT! 10 femtocells

10 femtocell users 1 macrocell user

12 femtocells, 12 femtocell users 2 macrocell users

24 femtocells, 24 femtocell users 1 macrocell user

SFR method is implemented and showing the positive result in increasing the data rate at the cell-edge and all the cell-edge users experience high SINR (and hence throughput)

Explanation IFR < SFR

Conventional Frequency Reuse Soft Frequency Reuse

Reuse-1 Reuse -3

Each cell uses the same

frequency, high spectral

efficiency, large intercell

interference, cell edge users can rarely retain connection

Same frequency is reuse every 3 sectors , low spectral efficiency.

This methods uses the same

frequency expect for the cell-edge

areas. For the cell-edge areas, the

frequency band is changed so that

adjacent cells do not cause

interference.

Average throughput performance for macro users at center

CASE 1

CASE 2

CASE 3

Average throughput performance for macro users at center

Throughput for macro users at cell’s borders.

CASE 1

CASE 2

CASE 3

Throughput for macro users at cell’s borders.

Experimental Results The table presents a comparison of all methods, versus the number of femtocells.

Femtocells No IFR FFR SFR

Throughput

(Mbps)

Throughput

(Mbps)

Throughput

(Mbps)

Throughput

(Mbps)

2 68.99 69.35 68.99 69.17

4 68.81 69.17 68.81 68.99

6 68.03 68.38 68.03 68.21

8 65.19 65.51 65.19 65.35

10 56.97 57.20 56.97 57.08

15 51.12 51.30 51.12 51.21

20 14.11 14.12 14.11 14.12

25 11.64 11.65 11.64 11.65

No ICIC = Red

IFR = Yellow

FFR = ***

SFR = Green

Performance : Average

SEM 1 PROGRESS For semester 1, my works focused on analyzing the LTE different interference mitigation techniques and simulation study and the result

obtained was investigated and analyzed according to the Matlab

Simulation methods.

Gantt chart for sem 1 Week 1 2 3 4 5 6 7 8 9 10 11 12 13 14

LTE Network

Identify interference in LTE/LTE-Advanced network

Searching simulation software

Simple simulation on IFR,FFR, and SFR

Identify femtocell interference management methods

Learn basic coding of IFR,FFR, and SFR

Simulate femtocell interference on Matlab

Analyse different interference mitigation

Simulation campaign

Data Analysis

Progress Report

PLANNING FOR SEM 2 WORKS • In the next sem, I will attempt to combine the desirable features from the

various existing frequency reuse schemes into a new integrated scheme.

• And I will attempt to design a new method that can reduce the

interference that occur in the the frequency reuse schemes used to

mitigate the inter-cell interference that caused by femtocells section

highlighted in the previous diagram.

• Make some modifications on the coding which Matlab code used for

simulation will be conducted in order to improve the effectiveness of the

frequency reuse schemes.

Gantt chart

Scheduled To-Do Things 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Study the code on Frequency Reuse Schemes

Analyze the Frequency Reuse Schemes

Perform more comprehensive Comparison study

Analyze on simulation results

Write final report and presentation

CONCLUSION • IFR,FFR and SFR schemes proposed with three cases to enhance the system capacity.

• IFR used up all the frequency spectrum which gives a good amount of throughput but

it may lead to strong co-channel interference at cell edge.

• FFR can improve the cell edge data capacity but this scheme is not fully deploy the

entire frequency spectrum which wastes the frequency resources.

• SFR is a good frequency partition method with power control on the physical resource

block (PRB) can resolved FFR issues.

• My next job to investigate the implementation of frequency reuse scheme or power

control in femtocells.

• Power control is better in data capacity enhancement but at the expense of some

frequency channels as it involves a lot of communications between macrocell and

femtocells.

• Also, there may still be other new unexplored methods for us to discover to reduce the

interference mitigation.

Future Work For Interference Coordination Method

THANK YOU

Fyp Presentation SEM1

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