Title page for ETD etd-09302009-162117

Type of Document Dissertation
Author Wang, Ying
Author's Email Address ywang06@vt.edu
URN etd-09302009-162117
Title Dynamic Cellular Cognitive System
Degree PhD
Department Electrical and Computer Engineering
Advisory Committee
Advisor Name Title
Bostian, Charles W. Committee Chair
da Silva, Claudio R. C. M. Committee Member
Hsiao, Michael S. Committee Member
MacKenzie, Allen B. Committee Member
Smith-Jackson, Tonya L. Committee Member
  • Cognitive Radio
  • Cognitive Radio Network
  • Signal Classification and Synchronization
  • Dynamic Spectrum Accessing
  • Channel Allocation
  • Software Defined Radio
Date of Defense 2009-09-25
Availability unrestricted
Dynamic Cellular Cognitive System (DCCS) serves as a cognitive network for white space

devices in TV white space. It is also designed to provide quality communications for first

responders in area with damaged wireless communication infrastructure. In DCCS network,

diverse types of communication devices interoperate, communicate, and cooperate with high

spectrum efficiency in a Dynamic Spectrum Access (DSA) scenario. DCCS can expand to a

broad geographical distribution via linking to existing infrastructure. DCCS can quickly form a

network to accommodate a diverse set of devices in natural disaster areas. It can also recover the

infrastructure in a blind spot, for example, a subway or mountain area. Its portability and low

cost make it feasible for commercial applications.

This dissertation starts with an overview of DCCS network. DCCS defines a cognitive radio

network and a set of protocols that each cognitive radio node inside the network must adopt to

function as a user within the group. Multiple secondary users cooperate based on a fair and

efficient scheme without losing the flexibility and self adaptation features. The basic unit of

DCCS is a cell. A set of protocols and algorithms are defined to meet the communication

requirement for intra-cell communications.

DCCS includes multiple layers and multiple protocols. This dissertation gives a comprehensive

description and analysis of building a DCCS network. It covers the network architecture,

physical and Medium Access Control (MAC) layers for data and command transmission,

spectrum management in DSA scenario, signal classification and synchronization and describes a

working prototype of DCCS.


Two key technologies of intra-cell communication are spectrum management and Universal

Classification and Synchronization (UCS). A channel allocation algorithm based on calculating

the throughput of an available is designed and the performance is analyzed. UCS is conceived as

a self-contained system which can detect, classify, and synchronize with a received signal and

extract all parameters needed for physical layer demodulation. It enables the accommodation of

non-cognitive devices and improves communication quality by allowing a cognitive receiver to

track physical layer changes at the transmitter.

Inter-cell communications are the backhaul connections of DCCS. This dissertation discusses

two approaches to obtaining spectrum for inter-cell communications. A temporary leasing

approach focuses on the policy aspects, and the other approach is based on using OFDMA to

combine separate narrowband channels into a wideband channel that can meet the inter-cell

communications throughput requirements.

A prototype of DCCS implemented on GNU radio and USRP platform is included in the

dissertation. It serves as the proof of concept of DCCS.

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