Vijay K. Madisetti

System on chip or system on package

The authors propose a new system design paradigm, the system on package, which uses electronic product reengineering to meet time-to-market and performance requirements. The system on package promises a higher return on investment than the system on chip.

The fast discrete Radon transform. I. Theory

An inversion scheme for reconstruction of images from projections based on the slope-intercept form of the discrete Radon transform is presented. A seminal algorithm for the forward and the inverse transforms proposed by G. Beylkin (1987) demonstrated poor dispersion characteristics for steep slopes and could not invert transforms based on nonlinear slope variations. By formulating the computation of a discrete computation of the continuous Radon transform formula, the authors explicitly derive fast generalized inversion methods that overcome the original shortcomings. The generalized forward (FRT) and inverse (IFRT) algorithms proposed are fast, eliminate interpolation calculations, and convert directly between a raster scan grid and a rectangular/polar grid in one step.

Streaming H.264/AVC video over the Internet

We propose a novel end-to-end architecture for streaming H.264/AVC (advanced video coding) unicast video over the Internet. The proposed video streaming architecture is based primarily on a new transport layer protocol, the stream control transmission protocol (SCTP). We show that the network-friendly specification of H.264/AVC and the novel technical characteristics of SCTP, when coupled together are able to provide a highly adaptive and flexible system for unicast video streaming. With simulation results we prove (1) that our system is capable of maintaining good perceptual quality under various loss conditions and (2) that the proposed system maintains TCP-friendliness.

Bandwidth aggregation with SCTP

We present a number of modifications to the stream control transmission protocol (SCTP) recently adopted by IETF; they allow bandwidth aggregation over the multiple interfaces of a host. We show that it is possible to implement a number of algorithms for bandwidth aggregation, with only a small number of modifications to the basic SCTP. Our simulation results clearly depict the efficiency of our approach in terms of bandwidth utilization. Furthermore, we implement and evaluate a mechanism for identifying bottlenecks that are shared by flows from the same aggregate connection. Our purpose is to show that SCTP is a good candidate for building a practical protocol for bandwidth aggregation that is fair and supportive of TCP.

Next-Generation Applications on Cellular Networks: Trends, Challenges, and Solutions

Applications over cellular networks now range from operator-consumer applications (e.g., mobile television, voice-over-ip, video conferencing), peer-to-peer applications (e.g., instant messaging), machine-to-machine applications (e.g., data telemetry and automotive applications), mobile web services (e.g., music and video streaming), and social networking applications. The current approach for developing mobile applications appears to focus on utilizing template-based application-development kits provided by platform developers (e.g., Googles Android, Apples iOS, or Nokias Symbian) to capture application designs and install them on the runtime platforms through use of code generators tied to particular versions of the platform. It is still unclear as to how an application developer (or network operator) conceptualizes the features of a mobile application in a platform-independent way, identifies its utility and explores its impact on the user, or further refines the choice of technology, platform, and mobility/interactivity requirements. This paper attempts to offer some guidelines, based on recent research in the industry and academia in these areas, toward the design and development of successful mobile applications that can utilize the capabilities of the next generation of cellular networks. We provide an overview of the growing trends of the rich multimedia and real-time mobile applications, including the diversity of application types, their impact on the enterprise and consumer, their traffic volumes, and their load and communication patterns. In addition to the overall trend analysis, we also study the design choices that are to be made, and how they are realized, and also describe how the platforms (client and server) may be implemented. Additionally, we focus on mobile video applications according to their communication characteristics and their distinct demands on the cellular network. We also present an analysis of device and network application programming interfaces (API) that form the basic building blocks for efficient and secure mobile application development of the future.

Incorporating cost modeling in embedded-system design

The emergence of multimedia and wireless applications as growth leaders has created an increased demand for embedded systems. Examples of such applications range from digital cellular telephones to high-performance avionics systems. Along with the increased market share of these products, however, has come an increase in system complexity and cost. For example, the complexity of embedded avionics systems has quickly grown from millions to billions of operations per second. These systems, formerly implemented in hardwired or uniprocessor architectures, now must consist of programmable-multiprocessor arrays to meet performance requirements. Time-to-market and life-cycle costs are key factors in the success of these products in the competitive electronics marketplace. These costs, therefore, should have a dominant influence on the design of embedded microelectronic systems. In addition, these systems must meet rigid form factor (such as size, power, and weight) constraints, which further complicate the design task. For designers of high-end embedded microsystems or large-volume consumer products, rapidly prototyping cost-effective implementations that meet stringent performance, functional, timing, and physical requirements is a formidable challenge.

Embedded Alamouti space-time codes for high rate and low decoding complexity

We introduce a new family of space-time codes called embedded Alamouti space-time (EAST) codes which offer high rate, a nonvanishing determinant and low decoding complexity. The family is parameterized by both the number of transmit antennas, which can range from two to eight, and by the rate, which can range from one to half the number of transmit antennas. The EAST codes combine a modified version of the perfect space-time codes with an Alamouti embedding. For rates higher than one, the resulting space-time codes are simultaneously lower in decoding complexity and better performing than all known previous constructions in terms of the error probability achieved on a quasistatic Rayleigh fading channel with a given dimension.

Using a new protocol to enhance path reliability and realize load balancing in mobile ad hoc networks

In this paper we introduce a novel end-to-end approach for achieving the dual goal of enhanced reliability under path failures, and multi-path load balancing in mobile ad hoc networks (MANETs). These goals are achieved by fully exploiting the presence of multiple paths in mobile ad hoc networks in order to jointly attack the problems of frequent route failures and load balancing. More specifically, we built a disjoint-path identification mechanism for maintaining multiple routes between two endpoints on top of the Stream Control Transmission Protocol (SCTP), and the Dynamic Source Routing (DSR) protocol. A number of additional modifications are incorporated to the SCTP protocol in order to allow its smooth operation. The proposed approach differs from previously related work since it consists of an entirely end-to-end scheme built on top of a transport layer protocol. We provide both analytical and simulation results that prove the efficiency of our approach over a wide range of mobility scenarios.

Software Streaming via Block Streaming

Software streaming allows the execution of stream-enabled software on a device even while the transmission/streaming may still be in progress. Thus, the software can be executed while it is being streamed instead of causing the user to wait for the completion of download, decompression, installation and reconfiguration. Our streaming method can reduce application load time seen by the user since the application can start running as soon as the first executable unit is loaded into the memory. Furthermore, unneeded parts of the application might not be downloaded to the device. As a result, resource utilization such as memory and bandwidth usage may also be more efficient. Using our streaming method, an embedded device can support a wide range of realtime applications. The applications can be run on demand. In this paper, a streaming method we call block streaming is proposed. Block streaming is determined at the assembly code level. We implemented a tool to partition real-time software into parts which can be transmitted (streamed) to the embedded device. Our streaming method was implemented and simulated on a hardware-software co-simulation platform in which we used the PowerPC architecture. We show a robotics application that without our streaming method is unable to meet its real-time deadline. However, with our software streaming method, the application is able to meet its deadline. The application load time for this application also improves by a factor of more than 10/spl times/ when compared to downloading the entire application before running it.

On fast algorithms for computing the inverse modified discrete cosine transform

Two new fast algorithms for computing the inverse modified discrete cosine transform (IMDCT) as used in the adaptive spectral entropy coder (ASPEC) (Brandenburg et al. 1991) are proposed. A fixed-point error analysis is presented to determine the number of significant bits required for fixed-point implementations.