Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"Decode-and-Forward."”.
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Adaptive Relay-Selection In Decode-And-Forward Cooperative Systems
In the past few years adaptive decode-and-forward cooperative diversity systems have been studied intensively in literature. Many schemes and protocols have been proposed to enhance the performance of the cooperative systems while trying to alleviate its drawbacks. One of the recent schemes that …
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Spectrally Efficient Bidirectional Decode-and-Forward Relaying for Wireless Networks
… zwei Stationen mittels einer Relaisstation miteinander kommunizieren. Wir untersuchen ein Zweiphasenprotokoll ohne Rückkopplung, in dem die Relaisstation die Nachrichten für beide Richtungen gleichzeitig dekodiert und weiterleitet. Damit kann der spektrale Verlust, verursacht durch halbduplexe …
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Performance Analysis of Decode-and-Forward Protocols in Unidirectional and Bidirectional Cooperative Diversity Networks
… spatial diversity, increase channel capacity, and attain broader cell coverage with single-antenna terminals. This thesis focuses on the performance study of both unidirectional and bidirectional cooperative diversity networks employing the decode-and-forward (DF) protocol. For the …
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Code design for the relay channel
… resources by cooperating at the symbol level to forward each other's physical layer packets collectively to the destination. The improved paradigm is known as cooperative communication. My work develops practical coding techniques that approach the theoretical limits of cooperation predicted by …
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Design and Analysis of Wireless Networks: Connectivity, Coverage, and Capacity
… This is true in various fading environments and for any causal strategy. This fundamental result shows that the current technological strategy of relaying by repeated decode-and-forward is order optimal even in the presence of fading.
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A hybrid relaying protocol for the parallel-relay network
… demonstrating that gains are achieved when a random subset of relays is selected. We derive threshold values for the received signal-to-noise ratios (SNRs) at the relays based on outage probabilities; these thresholds essentially determine the active subset of relays in each time frame for our …
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Relay assisted device-to-device communication with channel uncertainty
… due to the separation between the user equipment and due to the fading that the channel between these user equipment experiences. In order to fully realise the gains that direct (device-to-device) communication promises, idle user equipment can be exploited to serve as relays to enforce …
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Outage performance of cooperative cognitive relay networks
… to the growing scarcity of radio spectrum and the increased demand for wireless services. Cooperative relay networks can help cognitive radios to improve their utilisation by reducing their transmit power. This allows a reduction in their interference footprint and increases their …
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COOPERATIVE COMMUNICATIONS FOR LTE-ADVANCED SYSTEMS: DOWNLINK RELAY AND PERFORMANCE OPTIMIZATION
… to provide cost-effective throughput enhancement and coverage extension. While analog repeaters have been used to enhance coverage in commercial cellular networks, the use of more sophisticated fixed relays is relatively new. The main challenges faced by relay deployments in cellular systems are …
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Performance analysis of diversity techniques in wireless communication systems: Cooperative systems with CCI and MIMO-OFDM systems
… the bit error rate (BER) of dier- ent binary and M-ary modulation schemes, and the average channel capacity (ACC) under dierent adaptive transmission protocols, namely, the simultaneous power and rate adaptation protocol (OPRA), the optimal rate with xed power protocol (ORA), the channel …
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Design, Implementation and Characterization of a Cooperative Communications System
… of techniques which seek to improve reliability and throughput in wireless systems by pooling the resources of distributed nodes. While cooperation can occur at different network layers and time scales, physical layer cooperation at symbol time scales offers the largest benefit. However, symbol …
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Analysis and Optimization of Cooperative Wireless Networks
… to some resource constraints such as power, bandwidth, and time. However, in previous research, each optimization problem has been investigated separately, and the optimal solution for one problem is usually not optimal for the other problems.</p> <p>This dissertation focuses on joint …
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Adaptive signal combining and detection in cooperative wireless networks
… were developed for multiuser detection and signal combining in cooperative wireless networks. Some of the key contributions and works of this research thesis are: 1. A computationally simple Adaptive Minimum Mean Square Error Multiuser Detection scheme was proposed to eliminate multiple …
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Next-Generation Space Communications Technologies for Building Future Mars Connectivity
… stepping on the Martian soil. Thus, supporting and enhancing the life quality of a future crew should be the driving theme for accomplishing manned missions on Mars. In this regard, an on-demand, ubiquitous, reliable, wideband, and low-latency connectivity seems of vital importance, both for …
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Physical layer security: secrecy performance analysis and design of cooperative communication systems
… potential security risks, vulnerabilities and threats are still a possibility, such as eavesdropping and denial of service attacks, which have been an interesting subject for many researchers. To minimise the security risks of such attacks, researchers have attempted to secure the upper …
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Relay Selection Strategies for Multi-hop Cooperative Networks
… relay selection strategy for multi-hop decode-and-forward (DF) cooperative networks. In each relay cluster, relays that successfully receive and decode the message from the previous hop form a decoding set for relaying, and the relay which has the highest signal-to-noise ratio (SNR) link …
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Distributed Space-Time Message Relaying for Uncoded/Coded Wireless Cooperative Communications
… the broadcast nature of plane wave propagation, and may help to provide extra observations of the source signals to the destination. Modern research in wireless communications pays more attention to these extra observations which were formerly neglected within networks. Cooperative communication …
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Cooperative diversity aided direct-sequence code-division multiple-access systems
… systems, the distance between the relay and the destination receiver may be significantly shorter than that between the source transmitter and the destination receiver. Therefore, the transmission power of the relay may be significantly reduced in comparison to that of the source …
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Cooperative Strategies for Near-Optimal Computation in Wireless Networks
Computation problems, such as network coding and averaging consen- sus, have become increasingly central to the study of wireless networks. Network coding, in which intermediate terminals compute and forward functions of others’ messages, is instrumental in establishing the capacity of multicast …
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Distributed spectrum leasing via cooperation
… enable the coexistence of primary (licensed) and secondary (unlicensed) terminals. Conventional frameworks, namely commons and property-rights models, while being promising in certain aspects, appear to have significant drawbacks for implementation of large-scale distributed cognitive radio …
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