Location-based Channel Estimation for Massive Full-Dimensional MIMO

Systems

Authors: Wendong Liu, Chen Qian and Zhaocheng Wang

Presenter: Qian Han

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Outline

Abstract Introduction System model Proposal Simulation results References

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Abstract

Propose a two-dimensional location-based channel estimation for massive FD-MIMO systems

Intra-cell pilot reuse scheme is adopted Users with same pilots could be distinguished

by their non-overlapping A-AOAs and E-AOAs Interference is reduced and the sum capacity

could be improved

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Outline

Abstract Introduction System model Proposal Simulation results References

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Introduction

Massive MIMO is a promising technology for next generation wireless communication systems

Space limitation for large antenna arrays FD-MIMO (full-dimensional MIMO, 3D-MIMO)

is proposed and rectangular antenna array Massive FD-MIMO systems reach high

capacity

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Introduction With the same number of antennas, ULA perfomrs

better than URA More work will focus on optimizing FD-MIMO including

better precoding strategies or elevation beamforming A two-dimensional location-based channel estimation

algorithm is proposed with 2D-FFT-based post-processing is inserted after the conventional pilot-aided channel estimation

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Outline

Abstract Introduction System model Proposal Simulation results References

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System model A single-cell multi-user FD-MIMO system Pilot reuse: 2K users assigned with K orthogonal pilots Channel matrix between the l-th user and BS:

Pilot-aided estimated channel matrix: Antenna array size: Simplified 3D SCM

Fig. 1 K=12, single-cell pilot reuse pattern

,{ }l l xyhH

lH

y xM M

, , ,1

1 ( , )P

l l p l p l ppP

H B

P: number of paths, : large-scale fading parameter : A-AOA of the p-th path : E-AOA of the p-th path

,l p,l p,l p

1 p P

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System model Steering matrix :

Assumption: angular spread of A-AOA is small. E-AOAs are determined by locations of users.

Inner part user: Outer part user:

( , ) { }xyb B

cos cos sin, ( , )

jkD x yx yb e

0, 1, 0, 1x yx M y M

D: antenna spacing, , is the wavelength 2 /k

, min max[ , ]l ll p

min max m

arctan ,arctan , arctan ,arctanin outmid id

L L L Lr r r r

min m[ , ]in idd r r

m max[ , ]out idd r r

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Outline

Abstract Introduction System model Proposal Simulation results References

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Proposal: 2D-DFT Analysis Horizontal domain:

can be seen as a single-frequency signal with Vertical domain: : single-frequency signal with 2D-DFT of tends to a 2D- function with infinity

number of antennas. Different users have different impulse position and could be distinguished in angle domain.

1 2[ , , , ]y

h h hM B b b b

cos cossin

cos cos

1

y

jkDh jkDyy

jkDM

ee

e

b

hyb cos cosh

Df

sincos cos sin1 yjkDMv jkDx jkDx e e e b

vxb sinv

Df

B

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Proposal: 2D-DFT Analysis

Perform 2D-DFT of : 11

2 ( ) 2 ( )

0 0

112 ( ) 2 ( )

0 0

| ( , ) | | || |

| | | |

yxh h v v

yxh h v v

MMj q k j q k

h vx y

MMj q k j q k

x y

x y

X k k e e

e e

M M M

Let and( ) cos coshx

D kq kN

( ) sinvy

D kq kN

( , ) B

| ( , ) |h vX k k reaches maximum value when and both are integers( )hq k( )vq k

( , , )

( , )h h x

v v y

k g N

k g N

cos cos , [0, )2( , , )

cos cos , [ , ]2

x x

h x

x

DN Ng N

DN

min max( , ) sin , [ , ]v y y yDg N N N

Means rounding operation

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Proposal: Procedure Calculate the 2D window function in angle domain

: band-pass rectangle window

: pilot-aided estimated channel : 2D-FFT of : final estimated channel

1, ( , )( , )

0, ( , )h v

I h vh v

k k Ik k

k k I

W

max max min min min max

min min max max

0, ( , , ) ( , , ) , ,02

( , , ) , ( , , ) ,

l l l l l lh x h x x

hl l l l

h x h x

g N g N NI

g N g N otherwise

max min( , ) , ( , )l lv v y v yI g N g N

IW ( , )

h vl l I I I h vk k F F W

lH

lF lH

2 ( )(1: ,1: )l l x yIFFT M MH F

lH

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Outline

Abstract Introduction System model Proposal Simulation results References

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Simulation results Basic simulation parameters

Antenna configuration

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Simulation results

1. Proposed two-dimensional location-based channel estimation is better than conventional pilot-aided scheme

2. 3D MIMO improves sum capacity and can serve more users

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References

Thank you and questions please!