Collaborative uplink MIMO techniques
for IEEE 802.16m
IEEE C802.16m-08/638r4
Document Number:
IEEE C802.16m-08/638r4
Date Submitted:
2008-07-14
Source:
Mohamed Abdallah
Mohammed Nafie
Cairo University, Cairo, Egypt
Re:
IEEE 802.16m-08/024: Call for Contributions on Project 802.16m System Description Document (SDD)
Uplink MIMO
Abstract :
This contribution proposes coding schemes to be included in the SDD
Purpose:
For discussion and approval by TGm
Note: 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 >.
Collaborative MIMO
IEEE C802.16m-08/638r4
• Mobile stations (MS) can transmit at the same time in
the same frequency
– Improve system throughput by employing collaborate
spatial multiplexing (CSM)
• Rate 2 by using 2 BS ant. x 1 MS ant. configuration. (adopted by
IEEE 802.16e)
• Rate 4 by using 4 BS ant. x 2 MS ant. configuration.
– Interference mitigation can be provided at the BS by
• Proper selection of the MSs based on channel conditions.
• Applying Precoding techniques at the MS.
Open Loop CSM
IEEE C802.16m-08/638r4
• 2 (M.S) x 4 (BS) OL collaborative spatial
multiplexing (CSM) can achieve system
throughput of rate 4
• Matrix A used at each MS
s 
A 
s 
1
2
• At the BS, the 4 streams can be separated
given that the two MSs are chosen properly.
Closed Loop CSM
IEEE C802.16m-08/638r4
• Precoding techniques can be applied at the MS for the
CSM.
– Improve the performance of the CSM.
• At each MS, a precoding 2x2 matrix V is chosen
from a codebook such that the mutual interference at
the BS is eliminated given a proper receiver.
• Due to the limited power constraint at the MS
– The precoding matrix V should limit the power transmitted
per antenna.
Proposed SDD Text
IEEE C802.16m-08/638r4
• 11.x.x. MU MIMO
– For open loop CSM mode, two MS with 2 transmit
antenna can cooperate together by sending their
data using matrix A to a 4 receive antennas at the
BS.
– For closed loop CSM mode, precoding is applied
at each MS where the 2x2 matrix V is properly
selected to separate the 2 streams of each MS
efficiently at the 4 ant. BS.