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dc.contributor.authorWu, Victor Kai Yuenen_US
dc.date.accessioned2007-03-27T18:24:35Z
dc.date.available2007-03-27T18:24:35Z
dc.date.issued2006-11-10en_US
dc.identifier.urihttp://hdl.handle.net/1853/14114
dc.description.abstractIn this thesis, we investigate cooperation by applying OFDM signals to cooperative relay networks. We consider the single path relay network and the multiple path relay network. Using the amplify-and-forward relay algorithm, we derive the input-output relations and mutual informations of both networks. Using a power constraint at each relay, we consider two relay power allocation schemes. The first is constant gain allocation, where the amplifying gain used in the amplify-and-forward algorithm is constant for all subcarriers. The second is equal power allocation, where each subcarrier transmits the same power. The former scheme does not require CSI (channel state information), while the latter one does. We simulate the mutual informations using the two relay power allocation schemes. Results indicate that equal power allocation gives a slightly higher mutual information for the single path relay network. For the multiple path network, the mutual information is practically the same for both schemes. Using the decode-and-forward relay algorithm, we derive the input-output relations for both networks. The transmitter and each relay are assumed to have uniform power distributions in this case. We simulate the BER (bit error rate) and WER (word error rate) performance for the two networks using both the amplify-and-forward and decode-and-forward relay algorithms. For the single path relay network, amplify-and-forward gives very poor performance, because as we increase the distance between the transmitter and receiver (and thus, add more relays), more noise and channel distortion enter the system. Decode-and-forward gives significantly better performance because noise and channel distortion are eliminated at each relay. For the multiple path relay network, decode-and-forward again gives better performance than amplify-and-forward. However, the performance gains are small compared to the single path relay network case. Therefore, amplify-and-forward may be a more attractive choice due to its lower complexity.en_US
dc.format.extent563330 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectDecode-and-forwarden_US
dc.subjectAmplify-and-forwarden_US
dc.subjectRelayen_US
dc.subjectCooperative communicationsen_US
dc.subjectCooperative networksen_US
dc.subjectCooperationen_US
dc.subjectCooperative diversityen_US
dc.subjectOFDMen_US
dc.subject.lcshWireless communication systems Design and constructionen_US
dc.subject.lcshRelay control systems Design and constructionen_US
dc.titleOFDM-based Cooperative Communications in a Single Path Relay Network and a Multiple Path Relay Networken_US
dc.typeThesisen_US
dc.description.degreeM.S.en_US
dc.contributor.departmentElectrical and Computer Engineeringen_US
dc.description.advisorCommittee Chair: Geoffrey Li; Committee Member: Gordon Stüber; Committee Member: John Barryen_US


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