1. 2015/10/16IEEE S802.16m-08/6561 Cooperative MIMO with Randomized Distributed Space-Time Coding IEEE 802.16 Presentation Submission Template (Rev. 8.3) Document Number: IEEE S80216m-08_656 Date Submitted: 2008-07-07 Source: Chun Nie, Pei Liu, Thanasis Korakis, Shivendra Panwar Voice: 718-260-3740 Polytechnic Institute of New York University, Fax: 718-260-3074 (formerly Polytechnic University) Email: cnie01@students.poly.edu; 6 Metrotech, Brooklyn, NY 11201 pliu@poly.edu korakis@poly.edu; panwar@catt.poly.edu Venue: IEEE 802.16 Session #56, Denver, CO (uplink MIMO schemes) Base Document: IEEE C802.16m-08_656 Purpose: To incorporate cooperative MIMO with randomized distributed space-time coding proposed herein into IEEE 802.16m system description document (SDD). Notice: This document has been prepared to assist IEEE 802.16. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) 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. IEEE 802.16 Patent Policy: The contributor is familiar with the IEEE 802.16 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.16 Working Group. The Chair will disclose this notification via the IEEE 802.16 web site.

2. 2015/10/16IEEE S802.16m-08/6562 Cooperative MIMO with Randomized Distributed Space-Time Coding Chun Nie, Pei Liu, Thanasis Korakis, Shivendra Panwar Polytechnic Institute of New York University, Brooklyn, NY, 11201 (formerly Polytechnic University, NY) Authors:

3. Outline  Introduction  Randomized Distributed Space-Time Coding (R-DSTC)  Summary of R-DSTC Advantages  Performance Evaluation  Conclusions 2015/10/16IEEE S802.16m-08/6563

4. Introduction (1/2)  This contribution proposes the use of Randomized-DSTC to support Transmission Diversity in a virtual MIMO system  R-DSTC is a cooperative relaying system that uses Relay Stations (RSs) and Subscriber Stations (SSs) as “helpers” that form a virtual MIMO 2015/10/16IEEE S802.16m-08/6564 H1H1 d s s transmits to all the helpers ( 1 rst hop ) Helpers forward the packet simultaneously ( 2 nd hop ) H2H2 H3H3 HNHN......

5. Introduction (2/2) 2015/10/16IEEE S802.16m-08/6565 R-DSTC is implemented within a 2-hop system in either the uplink or the downlink –First hop: All potential helpers decode the source signal. –Second hop: Helpers cooperatively forward the signal to destination by using R- DSTC encoded signals.  Spatial diversity gain is achieved over the second-hop.  R-DSTC encoder is embedded in each helper as follows.  R-DSTC does not limit the number of antenna elements at each helper. Encoder’s output: L parallel streams, (one for an antenna in a STC MIMO system with L transmit antennas (Underlying space-time code G is of size L × K). Each helper transmits a different weighted sum of all L streams.

6. Summary of R-DSTC Advantages  Better than STC –Cooperation is fully utilized –Assists single-antenna SS in the uplink to achieve transmission diversity gain.  Better than conventional Distributed STC - A predetermined number of helpers in the system is NOT needed. –No need to index each helper and specify the STC codes for each of them. Thus, signaling is reduced. All potential helpers can contribute to cooperation. –SS can participate in cooperation and transparently cooperate with RS to enhance diversity gains. –Detailed channel information over the two hops is NOT necessary for rate adaptation. An approximate number of helpers can achieve GOOD performance. Hence, signaling for channel estimation is minimized. –R-DSTC is easy to implement in each helper station by using embedded software. No substantial increment of hardware complexity Conclusion: R-DSDC is more robust than DSTC (mobility, channel fluctuation) 2015/10/16IEEE S802.16m-08/6566

7. Performance Evaluation 2015/10/16IEEE S802.16m-08/6567 Setting: Single-hop: Direct transmission Two-Hop Single-Relay: One RS only R-DSTC Channel Info: Full Channel Information R-DSTC Neighbor Count: Ave Number of Helpers

8. Conclusions  R-DSTC can significantly enhance system performance in terms of throughput and delay.  When a large number of stations are in the system, an estimated number of helpers for R-DSTC can lead to performance comparable to R-DSTC with full channel information.  R-DSTC is more robust than a typical DSTC system  R-DSTC can be used in a multi-hop system  We suggest incorporating R-DSTC into IEEE 802.16m 2015/10/16IEEE S802.16m-08/6568