<html><body bgcolor="#FFFFFF"><div><br></div><blockquote type="cite"><div>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: center" align="center"> </p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: center" align="center">Optimal Beamforming Design for Two-Way Relay Networks</p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: center" align="center">Professor Shuguang (Robert) Cui, TAMU</p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: center" align="center">9/16/10 3:00pm N61 (basement), Engineering Building I</p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify"><o:p> </o:p></p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify">Abstract:</p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify"><o:p> </o:p></p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify">We then focus on the two-way relay system design under two different settings. In the first setting, we have a two-way relay channel (TWRC), where two single-antenna source nodes, S1 and S2, exchange information through one assisting multi-antenna relay node, R. It is assumed that R receives the sum signal from S1 and S2 in one time-slot, and then amplifies and forwards the received signal to both S1 and S2 in the next time-slot. By applying the principle of analogue network coding (ANC), each of S1 and S2 cancels the so-called “self-interference” in the received signal from R and then decodes the desired message. We then analyze the maximum achievable rate region of the ANC-based TWRC with linear processing (beamforming) at R via convex optimization techniques. We derive the optimal relay beamforming structure by solving a non-convex problem via SDP relaxation, and show that we could reconstruct the exact optimal rank-one beamforming structure from the relaxed solution for the originally non-convex problem. In the second setting, we have a distributed two-way relay system, where two single-antenna source nodes, S1 and S2, exchange information through a group of single-antenna relays. For both the reciprocal and non-reciprocal channel cases, we derive the optimal distributed beamforming relay strategy, and quantify the maximum achievable rate region. In particular, for the reciprocal channel case, we give the closed-form solution by exploring the underlying relationship between the rate region and the inverse-SNR region. For the non-reciprocal channel case, we solve the problem with similar SDP relaxation techniques to that used in the first setting with a single multi-antenna relay. </p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify"><o:p> </o:p></p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify">Bio: </p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify"><o:p> </o:p></p>
<p class="MsoNormal" style="MARGIN: 0in 0in 0pt; TEXT-ALIGN: justify">Shuguang Cui received his Ph.D in Electrical Engineering from Stanford University, California, USA, in 2005, M.Eng in Electrical Engineering from McMaster University, Hamilton, Canada, in 2000, and B.Eng. in Radio Engineering with the highest distinction from Beijing University of Posts and Telecommunications, Beijing, China, in 1997. He is now working as an assistant professor in Electrical and Computer Engineering at the Texas A&M University, College Station, TX. His current research interests include resource allocation for wireless networks, network information theory, statistical signal processing, and general communication theories. He was a recipient of the NSERC fellowship from the National Science and Engineering Research Council of Canada, the Canadian Wireless Telecommunications Association (CWTA) scholarship, two conference best paper awards, three NSF grant awards, and four DoD grant awards. He has been serving as the TPC chairs for the 2007 IEEE Communication Theory Workshop, the ICC'08 Communication Theory Symposium, and the GLOBECOM'10 Communication Theory Symposium. He has also been serving as the associate editors for the IEEE Transactions on Wireless Communications, IEEE Communication Letters, and IEEE Transactions on Vehicular Technology, and as the elected member for IEEE Signal Processing Society SPCOM Technical Committee (2009~2012).</p>
<p> </p>
</div></blockquote></body></html>