This thesis includes two topics. The first one is a low-power double-edge triggered flip-flop.The other is a orthogonal frequency division multiplex (OFDM) demodulator compliant with the Digital Video Broadcasting Handheld (DVB-H). Low-power double-edge triggered flip-flop (DETFF) is based on multi-Vth transistors technique. Since low threshold voltage transistors are able to generate large leakage current, they are suitable to drive big loads. By contrast, high threshold voltage transistors are more appropriate to latch data due to their low leakage. Therefore, a single latch double-edge triggered flip-flop utilizing multi-Vth transistors can be a low power and high speed design without paying the price of large area. The proposed OFDM demodulator is compliant with the DVB-H standard. The received DVB-H signal is processed by an RF front-end and the following analog-to-digital converter. Then, the digital signal is fed into the demodulator to adjust and calibrate the frequency, timing offset and channel estimation. The proposed DVB-H demodulator is mainly composed of five blocks : symbol timing synchronization block, carrier frequency offset compensation block, fast Fourier transform block, scatter pilot detection block and channel compensation block.

Reliable and energy-efficient delivery of multimedia to mobile terminals in dynamic networks is a very challenging problem. In this thesis, we focus on a cooperative extension to the Digital Video Broadcasting – Handheld (DVB-H) standard, forming a cooperative broadcast network whereby terminal-to-terminal cooperation creates a distributed form of multi-input-multi-output (MIMO) that supplements existing fixed network infrastructure. First, we develop a novel and computationally-efficient hierarchical Markov model that is able to accurately perform a cross-layer packet error mapping between the physical and transport layers of the DVB-H/IPDC (IP DataCast) protocol stack. We then construct a discrete-event simulator in MATLAB® that incorporates all of the necessary modules to conduct dynamic multiterminal network simulations. Next, the convergence of cooperative wireless communication, Raptor application layer forward error correction (AL-FEC) and Network Coding (NC) is examined. Originally proposed for broadcasting over the Internet, the application of Raptor codes to wireless cooperative communications networks has been limited to date, but they have been mandated for use in DVB-H. Network coding is used to reduce energy consumption by opportunistically recombining and rebroadcasting required combinations of packets. Two novel coding-enabled cooperative relaying protocols are developed for multicast and multiple unicast file distribution scenarios that are transparent, fully distributed, and backwards compatible with today's systems. Our protocols are able to exploit several different forms of diversity inherent to modern wireless networks, including spatial diversity, radio interface diversity, and symbol diversity. Extensive simulations show that our protocols simultaneously achieve breakthroughs in network energy efficiency and reliability for different terminal classes and densities, allowing greatly improved user experiences. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-08-03 19:45:54.943