Yahia Tachwali

Minimizing HVAC Energy Consumption Using a Wireless Sensor Network

This paper presents a conceptual design of a multizone HVAC controller based on a wireless sensor network that aims to optimize energy consumption while maintaining the comfort level of users. The proposed system is capable of learning the occupancy pattern of the residents in the building. Moreover, it is transparent (requires no manual configuration). Wireless sensor network technology is used to collect the required measurements for the control system, simulation results are used to demonstrate the system performance in terms of power consumption and comfort level Additionally, a comparison between the proposed system and other HVAC control systems is presented. The results show that the proposed system is capable of providing a major energy savings.

Cognitive radio architecture for rapidly deployable heterogeneous wireless networks

Recent technological advances in cognitive radio based on software defined radio platforms have extended the capabilities of wireless communication systems. The unique ability to alter communication protocols to meet changing system demands makes cognitive radio suitable for wireless applications otherwise difficult to implement using conventional wireless terminals. One such wireless application is the rapid deployment of a heterogeneous wireless network for the purpose of establishing a communication infrastructure between an incompatible set of wireless consumer devices. This paper presents the design and implementation details of cognitive radio terminals used to build a rapidly deployable, frequency-agile, heterogeneous wireless network. Research findings assisted researchers in the development of a wireless transceiver capable of connecting a variety of wireless transceivers, detecting the presence of interference, and accordingly switching to available channels as allocated by its spectrum sensing capability. The focus of this paper is to propose an architecture for cognitive radio terminals that can be used to build rapidly deployable wireless network applications.

Implementation of a BPSK Transceiver on Hybrid Software Defined Radio Platforms

Software defined radio (SDR) is an important element of wireless technology and fast becoming a hot topic in the telecommunication field. Determining the digital hardware composition of a software radio is a key design step in its creation. Hybrid GPP/DSP/FPGA architecture is a viable solution for software defined radio technology. This paper demonstrates a practical design and implementation procedure for a wireless digital modem on software defined radio platforms and reports a detailed description of the baseband signal processing logic design in the FPGA portion of it. Design verification is performed through hardware in the loop testing methodology. A framework for designing wireless digital modems on hybrid software radio platforms is discussed.

System prototype for vehicle collision avoidance using wireless sensors embedded at intersections

This paper presents research results regarding a vehicle collision avoidance system that uses a wireless sensor platform and communication based on 802.15.4 standard. The system is comprised of two components: monitoring stationary nodes mounted on the road and mobile nodes installed in vehicles. Signal strength and link quality indicators are evaluated to assist in the sequence identification of vehicles as they approach each other at an intersection. The study shows the feasibility of implementing 802.15.4 standard in wireless sensor network communication to act as a time-critical vehicle warning system that can be used for safety application.

A Frequency Agile Implementation for IEEE 802.22 Using Software Defined Radio Platform

This paper reports the design and implementation of a frequency agile software defined radio platform that is capable of performing a multi-resolution spectrum sensing. A fast spectrum sensing mechanism is implemented based on energy detection and a fine spectrum sensing mechanism is implemented based on feature detection. The platform is capable of switching to different communication channels in a spectrum range of 200-900 MHz which is compatible with IEEE 802.22 air interface. Different design considerations on the software defined radio platform are discussed. This study shows the feasibility of using software defined radio platforms as well as high level system design development tools to implement frequency agile cognitive radios.

Adaptability and Configurability in Cognitive Radio Design on Small Form Factor Software Radio Platform

The recent advances in cognitive radio technology based on software defined radio platforms have extended the capabilities of wireless communication systems. The unique ability of cognitive radios to alter their communication protocols to meet changing system demands make them great candidates for wireless applications that are difficult to implement using conventional wireless terminals. Small form factor platforms make cognitive radio portable and easy to deploy. This paper discusses the design and implementation methodology to build a cognitive radio on small form factor platform with heterogeneous processing architecture. The result of this discussion is a configurable wireless transceiver that features two important concepts of cognitive radio, namely configurability and adaptability.

The Feasibility of a Fast Fourier Sampling Technique for Wireless Microphone Detection in IEEE 802.22 Air Interface

The speed and accuracy of spectrum sensing techniques are essential factors in the performance of cognitive radio networks. The limitations imposed by computational complexity and limited monitoring time window impede the success of spectrum sensing operation performed by cognitive radio nodes. Compressive sensing technique is viewed as a novel approach to solve scalability problems in some signal processing operations. One popular application of compressed sensing is sizable image recovery. This technique can be used in spectrum sensing applications to reduce the barriers of current spectrum sensing computational requirements. The success of this technique will result in faster sensing operations, less complex sensing modules, or wider spectrum sensing capabilities. The coming IEEE 802.22 air interface standard aims to provide wireless services in wireless regional area network using TV spectrum white spaces. This standard is considered as the first standard that is based on cognitive radio approach. Spectrum sensing is a critical functionality that needs to be performed by 802.22 compliant devices. While, the standard does not specify any spectrum sensing method, it requires the sensing operation to be performed within timing and accuracy constraints. This work in progress is investigating the feasibility of using one of the compressive sensing techniques named Fast Fourier Sampling to detect wireless microphone signals for IEEE 802.22 air interface.

Configurable symbol synchronizers for software-defined radio applications

In many synchronous receivers, symbol timing synchronization is achieved through implementation of an analog phase locked loop (PLL). A phase detector and voltage-controlled oscillator drive a reference signal to be in phase with the received training sequence. Due to the quick phase convergence this option is attractive; however, limitations in pre-packaged hardware make this approach infeasible at times. Changes in the received symbol rate in software radio applications can further complicate the hardware implementation by requiring additional control signals to alter the frequency of the reference signal. This paper examines a configurable symbol synchronizer for software-defined radio (SDR) architecture with a predefined RF front end. In this scenario, we implement a typical method for digital phase locking and make it adaptable to different data rates. A pre-synchronization step is used to provide a reasonable initial estimate for the received symbol period for lower, over-sampled data rates. This decreases the synchronization time while maintaining a constant sampling period at the ADC. It also maintains the down-conversion stage at the receiver. The paper shows the feasibility of this architecture to support wide range of symbol rates.

Design and implementation of online mode switching on hybrid software radio platforms

This paper demonstrates the design and implementation of a configurable mode transceiver using software radio platform. The work implements a radio transceiver in which its communication modulation and frequency carrier can be altered while maintaining operation. The designed transceiver switches between amplitude modulation (analog) and differential binary phase shift keying (digital) upon a user request. While it is capable of automatically switching its frequency carrier upon an increase in bit error rate due to degradation of its wireless channel. The transceiver combines the signal processing modules to perform a configurable multimode radio. The design of the transceiver is implemented using a small form factor software defined radio (SDR).

Data collection and monitoring using cellular wireless network: GSM

Due to the rapid expansion of road and highway system around the world, there is a growing demand to monitor vehicle traffic patterns and road status by jurisdictional agencies charged with maintaining roads and ensuring the safety and usability of various highways within their jurisdictions. The feasibility of performing effective monitoring relies on cost, complexity and scalability of the traffic monitoring system. These factors are largely determined by the communication method between the monitoring system devices. This paper presents a novel application that uses commercially available wireless protocols coupled with Internet Protocol (IP) to integrate traffic counters placed at different locations with the State of Oklahoma. The system uses commercial cellular networks as its transport medium for communication with the traffic control. The system has been tested and deployed since July 2007 by Oklahoma Department of Transportation (ODOT).