Resource Management for Wireless Ad Hoc Networks

Open Access
Author:
Chen, Min
Graduate Program:
Electrical Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
September 11, 2009
Committee Members:
  • Aylin Yener, Dissertation Advisor
  • Aylin Yener, Committee Chair
  • William Kenneth Jenkins, Committee Member
  • Thomas F Laporta, Committee Member
  • Guohong Cao, Committee Member
Keywords:
  • wireless communications
  • wireless ad hoc networks
  • relay networks
  • resource management
  • power allocation
Abstract:
Wireless ad hoc networking is an emerging technology for next generation wireless communication systems due to its ability of providing communication without the need for infrastructure. In such networks, the system resources are limited: the terminals are constrained in energy, bandwidth, storage, and processing capabilities. As a result of the decentralized and possibly large scale network structure, resource management becomes a prominent design issue for wireless ad hoc networks. In this dissertation, we investigate resource management, with an emphasis on power, for various ad hoc networks including wireless sensor networks, parallel relay networks and multiuser two-way relay networks. We aim at providing efficient communication strategies that will fully utilize the limited resources to improve the Quality of Service (QoS) that ad hoc networks can offer. We first study efficient scheduling for a delay-constrained wireless sensor network. We consider a two-tiered model of clustered sensors, whose data collection includes intra- and inter-cluster communications. We first find the optimum schedule with polynomial complexity for intra-cluster communications, which minimizes the total power of all sensors while maintaining a short term average throughput at each sensor. Next, we show that the proposed scheduling protocol provides a near-optimum solution for inter-cluster communications where multi-antenna technique is employed. Next, we consider resource management for two types of relay-assisted ad hoc networks: parallel relay networks where the communication from a source to a destination is assisted by a number of intermediate relay nodes over orthogonal channels; multiuser two-way relay networks where multiple pairs of users exchange information with their pre-assigned partners via the help of a single relay node. Both relay networks in consideration are the building blocks of the future ad hoc networks. For the parallel relay networks, we first propose a distributed decision mechanism for each relay to make decisions on whether to forward the source data. Next, we identify the optimum power allocation strategy, based on limited channel state information, that minimizes the total transmit power while providing a target signal-to-noise ratio (SNR) at the destination with an outage probability constraint. In addition, We consider two simpler distributed power allocation models, where the source does not contribute to the relay selection in the first one, and single relay is employed in the second one. For the multiuser two-way relay networks, frequency/time/code division multiple access (F/T/CDMA) techniques can be employed to support multiuser communications. When F/TDMA is employed to provide orthogonal channels for each user pair, we investigate the optimum relay power allocation problem for various relay forwarding mechanisms to maximize the arbitrary weighted sum rate of all users. When CDMA is employed which results in an interference limited system, we design the multiuser two-way relaying scheme that allows each pair of partners to share a common CDMA spreading signature, and solve the interference management problem by constructing the iterative power control and receiver updates that converge to the corresponding unique optimum.