Link-State and Priority Based Relaying
Pinals, Lisa.
2017
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Abstract: Future 5G cellular and Wi-Fi networks will be denser and handle more wireless traffic than today's networks. Cooperative strategies will be fundamental in realizing the resulting wide range of service requirements in these dynamic networks. Relays are one such solution to improve both rate and reliability. How and when to utilize a relay will depend on the channel conditions, or link sta... read morete, as well as message priority. Link-state based decode-forward relaying is considered in the basic and the two-way relay channels. A composite relaying scheme combines coherent block Markov coding and non-coherent independent coding. The developed novel approach optimizes the composite scheme by analyzing the dual variable space to identify link-state regimes in which a particular combination of transmission techniques is optimal. The results expose an interesting trend: when the user- to-relay link is marginally stronger than the direct link, independent coding is optimal and the relay conserves power. For the two-way relay channel, these link-state regime results are also influenced by user priority. Next, this thesis examines relaying to guarantee message priority performance in terms of reliability. Each user is assumed to have a high and a low priority message. Using partial decode-forward relaying, it is optimal in certain link states to send the high priority message over both the relay and direct links, and send the low priority message over the direct link only - a strategy called differentiated relaying. Results demonstrate that differentiated relaying can guarantee higher reliability performance for the high priority messages. Lastly, this thesis considers link adaptation in fading channels. In fast fading, nodes employ long-term channel state information (CSI) and the outage probability is evaluated in closed form. In slow fading, nodes adapt the scheme to the fading link state to increase throughput and conserve relay power using practical CSI, in which nodes have perfect receive and long-term transmit CSI. A proposed maximum entropy quantization method to quantize and feed back the link state achieves near ideal performance at much reduced complexity. These link-state and priority based schemes directly support the application of relaying in future wireless networks.
Thesis (Ph.D.)--Tufts University, 2017.
Submitted to the Dept. of Electrical Engineering.
Advisor: Mai Vu.
Committee: Mai Vu, Rachel Learned, Boris Hasselblatt, and Eric Miller.
Keyword: Electrical engineering.read less - ID:
- 1544c145s
- Component ID:
- tufts:23105
- To Cite:
- DCA Citation Guide EndNote
