| In a collaborative wireless network, communicating nodes collaborate in routing and/or improving the quality of transmission of each other's packets. This is especially useful when the channel between a pair of nodes (source and destination) is in a deep shadow-fading state. In this situation increasing the power level may either not resolve the problem or be too power consuming, and it may increase interference for other receivers on the same channel. Alternatively, a cooperating node, which has good propagation channels to both the source and the destination, may be used to relay the packets between them. In this thesis we present analytical and simulation results for the outage probabilities of a standard network (non-collaborative) and a collaborative network operating in a shadow-fading environment, as well as the additional overhead that the collaborative scheme generates. We also present “multi-user spatial diversity” as a new method of diversity to combat the undesired shadow-fade situation. The average amounts of power consumed by nodes in a standard wireless network that uses single-hop transmission and a collaborative wireless network that uses two-hop transmission will be compared. It is shown that under certain conditions the ratio of the average power consumptions in the two networks, when N nodes are randomly distributed on a unit disk, can be approximated by k ln(N) + q. The constants k and q are related to the propagation channel. |
