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Closed-Loop Power Allocation for Space-time Coding in Project 802.16m SDD
Document Number: S802.16m-07/200Date Submitted:
November 12, 2007Source: Fan-Shuo Tseng, Yuan Pin Lin, Chun Fang Lee, Chieh Yuan Ho, Chung-Hsien Hsu, Ta-Sung Lee, Yu-Ted Su, Wen-Rong Wu, Kai-Ten Feng, Ching Yao Huang, NCTU/MediaTek Inc., 1001 Ta Hsueh Road, Hsinchu, Taiwan 300, ROC
Pei-Kai Liao ([email protected]) , I-Kang Fu ([email protected]) and Paul Cheng ([email protected])
MediaTek Inc. No. 1 Dusing Rd. 1 Hsinchu Science Park Hsinchu City 300 Taiwan.
Venue:Atlanta, GA
Base Contribution:IEEE C802.16m-07/200
Purpose:Propose TGm SDD to have a section “STC using closed-loop power allocation”.
Notice:This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein.
Release:The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that
this contribution may be made public by IEEE 802.16.
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<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>.Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.
S802.16m-07/200
2
Introduction
• Motivation– To achieve high rate and high reliability communication, one can
simultaneously transmit multiple groups via orthogonal space-time block coded design
– Double space-time transmit diversity (D-STTD) which contains two co-channel Alomouti STBC streams has been adopted in IEEE 802.16-2004 system
– Propose to utilize a simple closed-loop design for D-STTD scheme to enhance the link quality
– In section 5.7 of 802.16m SRD, “IEEE 802.16m shall support MIMO, beamforming operation or other
advanced antenna techniques.”• Purpose
– The technique is further extended as space-time coding with power allocation to increase link performance
– Propose to enable this functionality in IEEE 802.16m system
3
System Model
• Rx: MMSE-OSIC receiver
• 4 antennas at Tx; at least two antennas at Rx
• Only one parameter is needed to feedback in FDD system
Feedback power allocationcoefficient from Rx
1 1p x
3 3p x
4 4p x
S/PS/P Power allocationPower
allocation
1st STBCEncoder
1st STBCEncoder
2st STBCEncoder
2st STBCEncoder
2 2p x MMSE/OSICReceiver
MMSE/OSICReceiver
Power allocation After channel
estimation
Power allocation After channel
estimation
1 2 3 4x x x xxx̂
Fig. 1
4
Simulation
• Performance comparison for different receiver structure. QPSK constellation; Tx = 4, Rx = 2 antennas
5 10 15 20 2510
-7
10-6
10-5
10-4
10-3
10-2
10-1
SNR dB
BE
R
ZF
StamoulisMMSE
ZF-SIC-QR
ZF-OSIC
QR with optimal power loading
NaguibMMSE-OSIC
Proposed
[3]
5 dB[5]
[5]
Fig. 2
5
Proposed Texts in the Table of Content (ToC)
• x.y Space-time coding (STC)– x.y.z STC using closed-loop power allocation
[To support closed-loop power allocation, it is required to insert one functional block of power allocation immediately before STC encoder at the transmitter side. It also requires a reliable feedback channel from receiver to transmitter. Therefore, the trade-off here is the system complexity and uplink bandwidth. Fig. 1 illustrates an example of the system architecture. However, the antenna combination is not limited to 4(Tx)x2(Rx). The only condition to support this scheme is that at least two antennas at receiver and four transmit antennas have to be applied in the system.]
