Traffic Optimization for Multimodal Cooperative Networks

Resource allocation and traffic optimization are crucial problems in multi-traffic wireless networks as resources are scarce and the traffic is shared by multiple users. When application performance is the key concern in a network, utility is considered as a reliable metric. A lot of research has been done on capacity limits of wireless networks under some assumptions on the physics of propagation and some restrictions on the communication strategy employed by the nodes. It has been proved that due to the physical limitation that holds for any communication system, the decrease in throughput problem as wireless nodes increase in a fixed area cannot be overcome. In this thesis, multimodal networks, where other modes of communication like wires, infrared links may operate in addition to wireless nodes to improve the performance of the wireless network are studied and rate and power optimization problems are considered.;In this thesis, rate and power optimizations for heterogeneous traffic multimodal networks are proposed by solving them separately. First, the total rate is divided between delay-sensitive data and voice to achieve maximum utility in the network and in the next step, we divide transmit power between the wireless channel and the wired channel for a source-destination pair multimodal network and a diamond cooperative multimodal network implemented with Lanemann protocol. We consider a utility function for delay-sensitive data as a function of rate, reliability and delay and, the utility function of voice is a function of rate and delay. Traffic optimization problem is then solved by maximizing the sum of utilities of all voice and data users in the network and optimal rates that can be allocated to data and voice are calculated. Power allocation for a source-destination pair multimodal networks is done by optimizing instantaneous rate and outage probability in the network. For implementing a cooperative wireless relay network, we consider two cases: wire place between source and relay and wire placed between relay and destination. Optimal power allocation to wired and wireless channels is done by analytically minimizing the high-SNR outage probability expressions