In this thesis, we argue for node selection in cooperative decode-and-forward networks. In a single-hop network with multiple relays, we show that selecting a single node to aid in the transmission between a source and a destination outperforms both
traditional orthogonal transmissions and distributed space-time codes. In networks where sources transmit information over
multiple hops and relays can communicate with each other, we study the relationship between cooperation and channel-adaptive routing.
We show that cooperation is only beneficial if designed jointly with a routing scheme. This motivates a search for optimal algorithms in generalized relay networks.
In networks without restrictions on the relays in terms of whom they can communicate with, we study the problem of optimal
resource allocation in terms of transmission time. The resource allocation selects the relays to participate in the transmission
and optimally allocates time resource between the selected relays.
To implement this resource allocation algorithm, we propose a recursive solution which reduces the computational complexity of
the algorithm.
For large networks, the resulting computational complexity of implementing the algorithm is exponential in the size of the
network and is likely to preclude its implementation. We thus propose that the resource allocation be implemented sub-optimally through node selection: a subset of the nodes in the network should be selected and used as input to the optimal resource allocation algorithm. We provide guidelines for selecting the nodes and propose four heuristics which offer various
complexity-performance trade-offs. Compared to the optimal resource algorithm, all four heuristics significantly decrease the
required computation complexity of the optimal algorithm.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/17730 |
| Date | 23 September 2009 |
| Creators | Beres, Elzbieta |
| Contributors | Adve, Raviraj |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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