1

Uplink MIMO Proposal for IEEE 802.16mDocument Number: S80216m-08/744Date Submitted: July 16, 2008 Source:

shaohua Li (shaohua.li@nsn.com) Nokia Siemens Networks Peter Wang Qi xin Kang jianfeng

Wei chao Zexian Li (Zexian.li@nokia.com) Nokia

Venue: IEEE 802.16m-08/024 “Call for Comments and Contributions on Project 802.16m System Description Document (SDD)” in response to the following topic: “Uplink MIMO”

Base Contribution:IEEE C802.16m-08/744

Purpose: Discussion and Approval 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.

Patent Policy:The contributor is familiar with the IEEE-SA Patent Policy and Procedures:<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 >.

2

Outline

• Design Criteria and Requirements• MIMO Architecture• Single-user MIMO • Collaborative MIMO• CSI acquired for UL MIMO• Conclusions and Recommendations• SDD Text

3

Design Criteria and Requirements

• Improve coverage and increase the throughput

• Low system complexity and lower power consumption

• Support limited antenna configuration ½ lambda (1 or 2 Tx for each mobile)

4

MIMO Architecture

EncoderMIMO encoder Precoder

OFDM symbolConstruction

IFFT

IFFT

PMI

MIMO Mode SelectionMCS

BF Vector IndexACK/NACK

Retransmission Index

Notation:

• Only SCW is supported

• When only one transmit antenna is configured, MIMO encoder and precoder are not present in the above figure.

5

Single-user MIMO

• Open-loop– antenna Hopping

• Antenna hopping is simple in transmitter. It only needs few RFs, but antenna switch is necessary.• It will cause some power imbalance.

– STBC/SFBC/SM• STBC/SFBC can get better performance compared with antenna hopping

– CDD+STBC/SFBC/SM• It is not suitable to be used due to the limit number of transmit antennas.

• Closed-loop– Antenna selection

• With antenna selection, fewer RFs are needed, but antenna switch is still needed.

– precoding• Good performance• Precoding based on unitary codebook has good power balance property.

We propose to use STBC/SFBC/SM and precoding based on unitary codebook for OL/CL to improve the performance.

6

Collaborative MIMO

• Closed-loop– linear precoding can be used

The mapping from the steams to transmit antennas can be defined using

z = Px P : Nt x Mt weighting matrix

x: Vector with the output from the space-time coding

Nt: The number of actual transmit antennas

Mt: The number of streams at the output of the space-time coding scheme.

– P is signaling by BS

• Open-loop– Transmission mode is decided by BS, and P may be used and it can be

determined by MSs based on preamble and common pilots for TDD system.

• Constraint on Collaborative MIMO– In the same resource unit (RU), the number of streams, Mt, shall be same for

collaborative users

7

CSI acquired for UL MIMO

• For TDD frame structure– CSI can be acquired based on Downlink preamble and common pilots

– CSI can also be acquired by uplink sounding, and it is signaling by BS based on unitary codebook

• For FDD frame structure– Unitary codebook is used for signaling CSI information

8

Conclusion

open loop Notation

collaborativeMIMO

STBC/SFBC/SMprecoding

the number of streams of collaborative MSs shall be the same in the shared

RU

TDD FDD1.Acquired by UL sounding and DL

signaling2.Acqured by DL

preamble and common pilots

Acquired by UL souding

SU MIMO STBC/SFBC/SMprecoding based

on unitary codebook

close loop

precoding based on unitary codebook

CSI acquired

9

SDD text

• Please refer to C80216m-08_744.doc