Computational Complexity of Signal Processing Functions in Software Radio

The increased usage of mobile communication devices has imposed a challenge of achieving efficient communication with minimum power consumption. Moreover, with the advent of software defined radios (SDR), it is highly possible that signal processing functions would be implemented in software in future mobile devices. Hence, the power consumption of these future devices will be directly related to the power consumed by the processor that executes SDR software. This thesis aims at analyzing the computational complexity of different modulation schemes and signal processing communication functions of IEEE WiFi standard. This analysis provides good insight on how the computational load varies at different data rates for different modulation schemes. For this purpose, we have analyzed computational complexity of various modulation schemes and other communication functions using widely known software radio platform i.e. USRP hardware and GNU Radio open source software platform, Matlab and OProfile (open source Linux profiling tool). After performing an extensive analysis, we are able to determine how different modulation schemes and communication functions perform computationally on a given platform. This analysis would help to achieve effective communication along with the efficient use of power in SDR based system

Design of energy-efficient ultrasonic communication systems on steel pipes

Ultrasonic communication provides an alternative to radio-frequency (RF) by transmitting guided ultrasonic signals along installed or buried metallic pipes. Buried pipe corrosion monitoring and intermittent infrastructure data collection are potential application areas, for which reliable wireless links are unavailable, due to strong RF attenuation in soil, or through shielded building infrastructure. When designing a network of such links, energy efficiency, defined as the average energy per transmitted bit, can be far more important than Shannon capacity, for such battery-powered, relatively inaccessible links. This work focuses on the low-rate, total life-time energy-limited regime to maximize battery life, while maintaining reliable information transfer at a nominal average rate. The strong frequency selectivity of the through-pipe ultrasonic channel poses several challenges for low-power systems, including strong intersymbol interference (ISI). Previous works have suggested a variety of ad hoc design schemes to implement low-power communication systems satisfying minimum data rate requirements under highly frequency selective and lossy conditions, but failed to propose a systematic methodology to optimize design parameters for energy efficiency. In this work, we apply the concept of energy efficiency maximization to ultrasonic communication over steel pipe channels. A cross-layer approach accounting for both transmit power and signal processing power is suggested, where frequency division multiplexing is explored to counter frequency selectivity. Finally, bits-per-Joule capacity of this channel, based on experimentally measured channel responses, are determined numerically, and an example of an optimized multi-tone frequency shift keying (MFSK) scheme is suggested

Power Control Optimization of Code Division Multiple Access (CDMA) Systems Using the Knowledge of Battery Capacity Of the Mobile.

Power Consumption has become most important criteria in the design of wireless portable devices. The proposed work is on the study of the power control methods for different optimization objectives given the knowledge of battery power capacity. The target is planned to set on the single cell multi rate code division multiple access (CDMA) system with perfect successive interference cancellation (SIC) as our specific system. Different orderings for the SIC lead to different power contro