2 and 4 Tx MIMO System

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2 and 4 Tx MIMO System
CJK-B3G 11

• 10-11 April 2006

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Contents

• 1. Introduction
• 2. MIMO scheme set
• Two Tx scheme
• Four Tx scheme
• Closed-loop scheme for rate-1
• STC-HARQ scheme

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1. Introduction

• 1.1 Overall system

Feedforward
Feedback
MIMO
OFDM Tx
Coding and Modulation
LDC scheme
MIMO-Pilot
Downlink Multi-user MIMO
PAPR reduction scheme
Channel coder
Modulation
Uplink MIMO
Sub-carrier allocation
Scheduler H-ARQ, Power control, MCS adaptation,
Bit loading, Per stream power control, Per
antenna rate control, OFDM mode change, MIMO mode
change
Channel
Feedback overhead reduction
OFDM Rx
MIMO Demodulator
Decoding and Demodulation
Synchronization
MLD or QRM-MLD
Channel estimation
MMSE
CINR measurement
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1. Introduction

• 1.2 LDC (Linear dispersion code) 02 Heath, 02
  Hassibi
• Nt, Nr number of transmit and receive antennas
• T LDC period
• Q number of symbols
• Aq, Bq T x Nt dispersion matrix
• ai, bi real and imaginary value of ith symbol
• Every multi-antenna transmit scheme can be
  expressed in form of LDC
• Ex. Alamouti scheme

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1. Introduction

• 1.3 Design criterion
• Pairwise error probability (PEP)
• Capacity

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2. MIMO scheme set

• 2.1 Two Tx Rate-1 Scheme 98 Alamouti

2.2 Two Tx Rate-2 Scheme LGE proposal
2.2.1 Another candidates
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2. MIMO scheme set

• 2.2.2 Simulation result

CFgt IEEE802.16 Matrix-C has identical performance
with the proposal
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2. MIMO scheme set

• 2.3 Advantages

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2. MIMO scheme set

• 2.4 Four Tx Rate-1 scheme 04 Sethuraman

2.4.1 Another candidates
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2. MIMO scheme set

• 2.4.2 Simulation result

MMSE receiver
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2. MIMO scheme set
2.5 Four Tx Rate-2 scheme 04 Sethuraman
2.6 Four Tx Rate-4 scheme
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2. MIMO scheme set

• 2.7 Closed-loop MIMO
• 2.7.1 Codebook
• A set of pre-defined precoding matrices
• Moderate feedback overhead (36 bits)
• Selection criteria 03 Love
• ML
• MMSE

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2. MIMO scheme set

• 2.7.2 Four tx rate-1 closed-loop scheme LGE
  proposal

• 2.7.3 Advantage over codebook approach
• Low feedback overhead (1 bit)
• Less sensitive to mobility because of using
  channel statistics

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2. MIMO scheme set

• 2.7.4 Simulation

• Codebook size 8
• (3bit feedback required)
• Proposed scheme
• (1bit feedback required)

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2. MIMO scheme set

• 2.8 STC-HARQ (IEEE802.16e)

Alamouti pair
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2. MIMO scheme set

• 2.8.1 Adaptive STC-HARQ LGE proposal

Alternative 1
Alternative 2
Alternative 3

• ACK/NACK signals (2bits)
• ACK,
• NACK w/ alt 1,
• NACK w/ alt 2,
• NACK w/ alt 3

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2. MIMO scheme set

• 2.8.2 Simulation Results
• 802.16e system
• 20ms difference between transmission and
  retransmission

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• Thanks