1. Collaborative uplink MIMO techniques for IEEE 802.16m
Document Number:
C80216m-08/638r2
Date Submitted:
7/7/2008
Source:
Mohamed Abdallah
Mohammed Nafie
Cairo University, Cairo, Egypt
Venue:
Call for contributions on project m SDD
Session #56: Denver, USA
Target topic: .
Uplink MIMO.
Base Contribution:
C80216m-08/638
Purpose:
For discussion and approval by IEEE m group.
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2. 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 e)
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.

3. 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
At the BS, the 4 streams can be separated given that the two MSs are chosen properly.

4. 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.

5. 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.