Collaborative uplink MIMO techniques for IEEE 802.16m

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Collaborative uplink MIMO techniques for IEEE 802.16m
Document Number:
C80216m-08/638r1
Date Submitted:
7/7/2008
Source:
Mohamed Abdallah
Mohammed Nafie
Cairo University, Cairo, Egypt
Venue:
Call for contributions on project 802.16m SDD
Session #56: Denver, USA
Base Contribution:
C80216m-08/638
Purpose:
For discussion and approval by IEEE 802.16m group.
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.
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Collaborative MIMO
• 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
• 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
• 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
• 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.
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