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 lin... read morek state, 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
