Reizel Casaquite

Evaluation and Optimization of Joint Scheduling, Power Control, and Routing in Ad Hoc Wireless Networks

Cross-layer design is an extensive research area in ad hoc wireless networks, particularly under energy constraints. In this paper, we formulate an optimal link scheduling and power control that supports a particular data rate while satisfying the Signal to Interference plus Noise Ratio (SINR) and the maximum transmission power constraints at each node. We also present an optimization problem considering the energy consumed of each node in the routing path and the delay associated on each transmission as link costs. The problem is to minimize the energy link cost and the end-to-end delay for all nodes lying in the routing path subject to certain constraints. We provide numerical examples for our schemes and relationships between the parameters. An overview of our intended routing algorithm for ad hoc networks is also given. This paper is a preliminary step towards our distributed joint scheduling, power control and routing algorithm for ad hoc networks using cross layer approach.

Opportunistic Scheduling with Power Control in Ad Hoc Wireless Networks

To exploit the multiuser diversity in the CSMA/CA based wireless ad hoc networks, this paper proposes a new algorithm for opportunistic scheduling that will take advantage of both multiuser diversity and power control. The scheduling scheme is performed first before power control to further enhance throughput. The scheduling scheme ensures that the transmission is successful since a best candidate receiver is chosen for transmission and hence minimizes retransmissions. Likewise, the power control algorithm helps reduce interference between links and maximizes spatial reuse. In our study, we provided the scheduling scheme and the power control algorithm. We also showed optimal solutions for minimizing power consumption and maximizing net utility

Optimization decomposition in energy-constrained wireless networks

This study considers a joint congestion control, routing and power control for energy-constrained wireless networks. A mathematical framework is introduced which includes maximization of network utility, maximization of network lifetime and trade-off between network utility and network lifetime. The framework would maximize the overall throughput of the network where the overall throughput depends on the data flow rates which in turn is dependent on the link capacities. The link capacity, on the other hand, is a function of transmit power levels and link Signal to Interference plus Noise Ratio (SINR) which makes the power allocation problem inherently difficult to solve. Using dual decomposition techniques, subgradient method and logarithmic transformations, a joint algorithm for rate and power allocation problems was formulated. Numerical examples for each optimization problem were also provided.

Link Scheduling, Power Control, and Routing in Ad Hoc Wireless Networks: A Joint Optimization

Ad hoc network is an extensive research area in wireless communications nowadays, and is particularly studied under energy constraints, since energy consumption of the network should be minimized. The physical layer (power control), link layer (scheduling), and network layer (routing) are known to have great impact on network performance as well as on power consumption. In this paper, we present an optimization problem that there may exist a power vector that minimizes the overall transmission power of the network which at the same time supports a particular data rate on each link and satisfies the SINR and maximum transmission power constraints at each node. We also formulate an optimization problem where we use both the energy consumed of each node in the routing path and the delay associated on each link as link costs. We provide numerical examples for our schemes and relationships between the parameters. An overview of our intended routing algorithm for ad hoc networks is also given as a preliminary step towards our distributed joint scheduling, power control and routing algorithm for ad hoc networks using cross layer approach.

Joint Optimization of Link Scheduling, Power Control, and Routing in Ad Hoc Wireless Networks

Cross-layer design is an extensive research area in ad hoc wireless networks and is particularly important under energy constraints. The physical layer, link layer, and network layer are known to have great impact on network performance as well as on energy consumption; hence, the interactions between these layers should be studied. In this paper, we formulate an optimal link scheduling and power control policy that supports a particular data rate on each link in the network while satisfying the Signal to Interference plus noise ratio (SINR) and the maximum transmission power constraints at each node. We present an optimization problem considering both the energy consumed of each node in the routing path and the delay associated on each link as the link cost metrics. The problem is to find an optimal link scheduling, power control and routing policy that minimizes the end-to-end delay as well as the energy link cost subject to certain constraints. We provide numerical examples for our schemes and relationships between the parameters i.e. the higher the required data rate and the higher the SINR requirement; the system will become less energy-efficient since a high transmission power is needed. This paper is a preliminary step towards our distributed joint scheduling, power control and routing algorithm for ad hoc networks using cross layer approach

Optimization and routing discovery for ad hoc wireless networks: a cross layer approach

Wireless communication links are time-varying in nature, causing degradation of networks performance; this however, could be alleviated by allowing cross layer interaction in the protocol stack. Hence, optimization problems formulated in this paper considered parameters from the physical, MAC, and network layers where an optimal transmission power vector that minimizes the overall transmission power of the network, satisfying the SINR, required data rate, and maximum transmission power constraints was formulated to exist. Distributed algorithms for the joint scheduling, power control and routing were also derived and an energy-aware routing algorithm which maximizes network lifetime was proposed. The energy consumed by each node in the routing path and delays associated on each transmission were considered as link cost such that a route with minimum link cost is utilized. Basically, the routing algorithm searched an energy-efficient route, satisfying the energy constraint of each node in a routing path at a tolerable delay.