University of Delaware - College of Engineering


Communication & Signal Processing

OFDM for Cooperative Networks

Leonard J. Cimini, Jr.

The modularity of OFDM and the fact that it will be used in many current and future systems makes it very appealing for consideration in cooperative wireless networks. More importantly, the use of orthogonal signaling and the inherent frequency diversity in a well-designed OFDM system are especially useful in attempting to obtain the maximum benefits from cooperation - in both single- and multi-source applications. Achieving these gains, however, depends on devising practical relay and subchannel management strategies with different levels of channel state information (CSI).

Although there has been a significant effort on the study of cooperative systems, there has been very little work on the use of OFDM in these networks. In most of the work in this area, OFDM is simply the underlying transmission technology. Relatively few works, incorporate the assignment of individual subchannels into the cooperation among relays.

In our work, we have focused on the use of OFDM as a relay management strategy to facilitate cooperation among nodes in a wireless network. In particular, we have studied the performance of various schemes for assigning subchannels to nodes in the presence of varying amounts of CSI at the relays. In addition, we have developed novel OFDM-based routing protocols for multihop networks.

Recent publications

B. Gui, L. Dai, and L. J. Cimini, Jr., "OFDM for Cooperative Networking with Limited Channel State Information," to appear in Milcom 2006.

L. Dai, B. Gui, and L. J. Cimini, Jr., "Selective Relaying in OFDM Multihop Cooperative Networks, " submitted to WCNC 2007.

B. Gui, L. Dai, and L. J. Cimini, Jr., "Routing Strategies in Multihop Cooperative Networks," submitted to WCNC 2007.

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