MIMO Mode Selectiongssst.iitkgp.ac.in/GSProjects/DIM/Seminar_dim_subhajit... · 2018-09-06 · Subhajit Paul. Contents •Introduction To MIMO Modes In LTE •MIMO Mode Selection

MIMO Mode Selection

By

Subhajit Paul

Contents

• Introduction To MIMO Modes In LTE

• MIMO Mode Selection

• Problem Definition and State of the Art

• Literature Survey

1/23/2012 2IIT Kharagpur, Extension Center, Kolkata

Activities Undertaken till date

19th January 2012 3IIT Kharagpur Extension Centre,Kolkata

Hardware (Phy)

MATLAB/ HW

System Simulator

PS/RRA-MIMO

Fractional Reuse

Algorithm

WORK PLAN

Optimal Packet Scheduling

and RRA

OLLA PC/ HW (Simulink)

Software (Phy)

Fractional Load

MIMO Mode Selection

PMI Coordination

Coordinated Scheduling

Test Bed

Phy Simulator

Fractional Load

Fractional Reuse

Introduction

to

MIMO Modes in LTE


Layout of a Cellular Network


MIMO Modes in LTE

Multiple Antenna Schemes

SISO SIMO

Receive Diversity

(e.g. 1 x 2 MRC)

MISO

Transmit Diversity

(e.g. 2 x 1 AlamoutiSFBC)

MIMO

Diversity

(4 x 2 Alamouti SFBC –FSTD,

2 x 2 SFBC)

Spatial Multiplexing

Single User (SU-MIMO)

Open Loop Spatial Multiplexing

Closed Loop Spatial Multiplexing

Multi User (MU-MIMO)

Dedicated Beamforming


Transmitter Receiver

MIMO Modes in LTE


SISO SIMO

Receive Diversity

(e.g. 1 x 2 MRC)

MISO

Transmit Diversity


MIMO

Diversity


2 x 2 SFBC)









MIMO Modes in LTE


SISO SIMO

Receive Diversity

(e.g. 1 x 2 MRC)

MISO

Transmit Diversity


MIMO

Diversity


2 x 2 SFBC)









MIMO Modes in LTE


SISO SIMO

Receive Diversity

(e.g. 1 x 2 MRC)

MISO

Transmit Diversity


MIMO

Diversity


2 x 2 SFBC)









MIMO Modes in LTE


SISO SIMO

Receive Diversity

(e.g. 1 x 2 MRC)

MISO

Transmit Diversity


MIMO

Diversity


2 x 2 SFBC)








Single User MIMO


Layer 2

Layer 1

Layer 3

Layer 4

User 1

Multi User MIMO


User 2

User 1

User 3

User 4

Precoder

SU-MIMO Open Loop Spatial Multiplexing

Serial To Parallel Converter

.

.

. ...

Receiver

.

.

.

s1 s2 s3 …

s1

s2

sL

x1

x2

xM

y1

y2

Number of data layers = LNumber of transmit antennae = MNumber of receive antennae = N

Channel H is a N x M matrixPrecoder is a

Cyclic Delay Diversity

Precoding

yN


Precoder

SU-MIMO Close Loop Spatial Multiplexing


.

.

. Receiver

s1 s2 s3 …

s1

s2

sL

Number of data layers = LNumber of transmit antennae = MNumber of receive antennae = N

Channel H is a N x M matrixPrecoder is a

PMI SelectionBased on Feedback

Precoding

PMI Feedback from UE

.

.

.

x1

x2

xM

y1

y2

yN


Precoding Matrices for LTE

4 x 4 Identity Matrix

4 x 1 ith generating vector

4 x 4 generating matrix


Precoder

MU-MIMO


.

.

.

Receiver 1

s1 s2 s3 …

s1

s2

sL

PMI SelectionBased on Feedback

Precoding

.

.

.

x1

x2

xM

y1

y2

yN

Receiver 2

Receiver 3


MIMO Mode Selection


Why Mode Selection Is A Necessity

The Channel Quality effect each MIMO Mode Differently

In order to analyse the various MIMO modes

Simulation has been done for

4 x 2 Closed Loop Rank 1 Transmission (CLR1)

4 x 2 Space Frequency Block Coding with Frequency SwitchedTime Diversity (SFBC-FSTD)


SINR (Averaged over available bandwidth)


1x2 MRC Wideband SINR

4x2 CLR1 Wideband SINR

4x2 SFBC-FSTD Wideband SINR

SINR (dB)

Pro

b(S

INR

< s

inr)

Inference : SINR Gain is higher for closed loop MIMO modes


Simulation Scenario

Mode of Transmission Interfering Modes

CLR1 SFBC-FSTD

CLR1 CLR1

SFBC-FSTD SFBC-FSTD

SFBC-FSTD CLR1

1/23/2012 IIT Kharagpur, Extension Center, Kolkata 21

Simulation Scenario


CLR1 SFBC-FSTD

CLR1 CLR1

SFBC-FSTD SFBC-FSTD

SFBC-FSTD CLR1


Packet Error Rate for Different MIMO Modes


G - factor

Packet E

rror

Rate

4x2 CLR1

4x2 SFBC-FSTD

PER for Compressed CQI VoIP Simulation

Simulation Scenario


CLR1 SFBC-FSTD

CLR1 CLR1

SFBC-FSTD SFBC-FSTD

SFBC-FSTD CLR1


Packet Error Rate For Different MIMO Modes


Packet Error Probability for CLR1 Transmission

Packet Error Probability for 4x2 SFBC-FSTD Transmission

PE

RP

ER

Geometry (dB)

Geometry (dB)

Simulation Scenario


CLR1 SFBC-FSTD

CLR1 CLR1

SFBC-FSTD SFBC-FSTD

SFBC-FSTD CLR1


Inference : Packet Error Rate (PER) is higher for MIMO modes below UE geometry factor (G-factor) of 10 dB


Difference Between Estimated And Actual SINR


diff-sinr (dB)

Pro

b (

Diffe

rence in

SIN

R <

diff-

sin

r)

Difference between Actual SINR and Estimated SINR as a function of G - Factor

G-Factor > 10 dB

G-Factor 5-10 dB

G-Factor 0-5 dB

G-Factor <0 dB

Multi BS RRA Coordination

• The serving BS could can assign specific PRBs to various MIMO modes that will lead to reduced interference for low SINR UEs

PRB allocation

Open Loop Diversity Mode (4 x 2 SFBC-FSTD)

Closed Loop Diversity Mode (4 x 2 CL-R1)


Problem Definition



The Focus of the Project is towards:

Obtaining Average SINR Threshold for Mode Switching

Devise an algorithm for bandwidth partitioning across MIMO modesdepending on: Resource usage by the MIMO mode

Estimated User distribution to be assigned to the MIMO mode

Base Station Cooperation

Other Aspects of the algorithm includes:

Reduced Computation Complexity

Reduced Feedback Overhead

Literature Survey


State of the Art – Feasibility Study

Sl. No.

Title Paper Details Contents

1 Adaptive MIMO Mode and Fast Cell Selection with InterferenceAvoidance in Multi-Cell Environments

Seung-Wan Kim, Yong-Hwan Lee ‘2009, International Conference on Wireless and Mobile Communications (ICWMC), 2009

Addresses MIMO Mode Selection problem in MIMO-OFDM systems•Considers FCS and FFR•Mode Selection is done on the basis of ergodiccapacity•Calculation complexity overhead is increased at MS due to calculation of ergodic capacity

2 MIMO Base Station Antenna Employing Mode Selection in Vertically Split Array

Yuki Inoue, Keizo Cho ’2011, European Conference on Antenna and Propagation (EuCAP), 2011

Enhances Mode Selection throughput by vertically-split antenna design•3G Antenna vs. MMS-VS Antenna•Effect of Path Loss on MIMO Modes•BS Antenna Deployment requires to be changed

3 Closed-Loop Hybrid MIMO System with Joint Transmit Antenna and Mode Selection based on Capacity Maximization

Andre L. F. de Almeida, Icaro L. J. da Silva, F. Rodrigo P. Cavalcanti‘2010, International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2010

Presents Hybrid MIMO system with joint selection of Transmit Antenna and Transmission Mode•Multi-layer Precoded data is spread in space-time for diversity•Antenna Selection is performed•Receiver Complexity will be very high•Amount of feedback will be increased


This project aims towards a reduced

Computation Complexity

This project aims towards achieving

targets with minimum changes in the

existing infrastructure

This project aims towards reduced

feedback overhead

State of the Art – Feasibility Study

Sl. No.

Title Paper Details Contents

4 Methodology for Mode Selection in MIMO-OFDM System

Peter W.C. Chan, Z.G. Pan, Xueyuan Zhao, C.M. Lo, Kai Zhang, Derek C.K. Lee ‘2008, IEEE Wireless Communications and Networking Conference, 2008

Addresses MCS Selection in MIMO-OFDM systems for different Modes•Selection is done for maximizing goodput•Algorithm for Mode Selection not specified

5 Adaptive MIMO Systems in 2 × 2 Uncorrelated Rayleigh Fading Channel

Jinliang Huang, SvanteSignell ‘2007, IEEE Wireless Communications and Networking Conference, 2007

•Spectral Efficiency based Mode Selection•Addresses closed loop systems

•Perfect CSI feedback is assumed•Does not address Diversity/Open Loop systems•Spectral efficiency is calculated using average SINR


We are moving towards SINR Threshold

based Mode Selection

This project aims towards reduced

feedback overhead

Time Plan


Activity Year 1 Year 2 Year 3

Literature Survey

Building the

Simulator

Analysis of the

Results

Proposed Solution

Analysis of the

New Results

Contemporary

Literature Survey

Final Report

Preparation

Appendix


Enhancements to Semi-Persistent Scheduling

VoIP Packet Arrives at Packet Scheduler Buffer and are

required to be delivered within an interval of 50 ms

PS Buffer packets are arranged according to ascending order of remaining time

Frequency Domain allocation is done for each

packet that can be accommodated within the

available bandwidth. Allocation is recorded in

persistent table

Packet is transmitted

Transmitted Successfully?

Retransmission packet?

Frequency Domain allocation in Semi

Persistent Table is used

User in persistent table?

MCSCURR in [MCSSP + Δ,

MCSSP - Δ ]

Packet is added to PS

buffer as a HARQ

packet

YES

YES

YES

YES

NO

NO

NO

NO

PMI is updated for the packet being

transmitted


Precoding – Spatial Multiplexing

The transmitted Signal from the desired base station is

L x 1 data symbol vectorM x 1 transmit symbol vector

M x L Precoding Matrix

The received signal at the UE is

N x M channel coefficient matrix

N x 1 Noise Vector

N x 1 received signal vector The equalized signal is

estimated signal vectorsignal vector

noise vectorinterference vector


Documents

MIMO Mode Selectiongssst.iitkgp.ac.in/GSProjects/DIM/Seminar_dim_subhajit... · 2018-09-06 · Subhajit Paul. Contents •Introduction To MIMO Modes In LTE •MIMO Mode Selection