High Data Rate Stream Research Articles

Vys: A Protocol for Commensal Fast Transient Searches and Data Processing at the Very Large Array

We describe a new protocol deployed at the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array (VLA) to support the distribution of data in support of commensal data analysis. The protocol, vys, is designed to provide access to a high time resolution data stream while a primary observation continues with the typical (lower) time resolution data stream. This form of dual time resolution, commensal observing has been implemented to enable the search for millisecond astrophysical transient events by a new, dedicated compute cluster located at the VLA. The fast transient detection system, realfast, performs real-time analysis in situ to detect events of interest and record relatively short duration data “cut-outs” of those events. By selectively recording high time resolution data, provided by vys at rates of up to 1.4[Formula: see text]GB[Formula: see text]s[Formula: see text], realfast will reduce the recorded data volume by an estimated factor of up to 1000. This makes it possible to search for transients commensally in a high data rate stream over the thousands of hours needed to find the rarest events.

SoPC Self-Integration Mechanism for Seamless Architecture Adaptation to Stream Workload Variations

Field-programmable gate arrays are becoming one of the implementation platforms of choice for computationally intensive embedded applications, such as multimode stream processors; such systems often exhibit poor cost-efficiency as various system modules can be idle, based on operating mode. This problem can be addressed through the use of reconfigurable computing, which allows underlying logic resources to be shared among system modules; using this approach, an application and mode specific processor can be generated at run-time. However, this generation process can interfere with application workloads; this is particularly true in the case of high data-rate stream processors. To address this problem, this brief presents a system-on-programmable-chip self-integration mechanism aimed at reconfigurable stream processors. The proposed mechanism is implemented using a distributed architecture and the multimode adaptive collaborative reconfigurable self-organized system framework. The mechanism arranges configuration, link establishment, and scheduling tasks around the stream workload, which allows for seamless run-time architecture adaptation. When compared with traditional approaches, based on central, instruction-based sequential processors, the proposed approach is shown to offer a faster (up to 10 times) link establishment and the scheduling capabilities; more importantly, the proposed mechanism can offer seamless run-time architecture adaptation by allowing the overlap of processing and configuration tasks.

Application of Superposition Coding for Subcarrier and Bit Allocation in Downlink OFDM Systems

Orthogonal frequency division multiplexing (OFDM) is well known for multicarrier modulation technique in which a high data rate stream is divided into different parallel lower data stream. In this paper, we study the margin adaptive - superposition coding (MA-SC) algorithm and rate adaptive - superposition coding (RA-SC) algorithm, where at most two user can share each subcarrier as compared to MA and RA algorithm, where each subcarrier is shared by only single user without SC scheme. We apply SC scheme over MA and RA to achieve maximum system throughput with separate power constraint for real and non real time users, ensuring that QoS requirement for real time and proportional fairness among non real time users is satisfied. The overall computational complexity of proposed modified RA-SC algorithm is same as RA algorithm. In the modified proposed MA-SC, complexity increases in some of the steps due to addition of SC scheme over MA algorithm, but overall complexity remains the same. Monte-Carlo simulations are being carried out to show that the proposed algorithm improves the performance in terms of power required and throughput.

Processing high data rate streams in System S

High-performance stream processing is critical in many sense-and-respond application domains—from environmental monitoring to algorithmic trading. In this paper, we focus on language and runtime support for improving the performance of sense-and-respond applications in processing data from high-rate live streams. The central tenets of this work are the programming model, the workload splitting mechanisms, the code generation framework, and the underlying System S middleware and Spade programming model. We demonstrate considerable scalability behavior coupled with low processing latency in a real-world financial trading application.

Configurable RF receiver architectures

In the heterogeneous world of communication and radar systems, a steadily increasing number of technical approaches for different applications are observed. A new application on the horizon is the transmission of very high data rate streams (> 500 Mb/s) during a short time interval between moving clients. Such applications may be applicable to future intelligent traffic control systems based on R.D. Kuhne (2002) and will require the support of different standards for communication and radio location services. The high data rates require high bandwidths, which become available at millimeter wave frequencies. From an engineering point of view, we may not be unsatisfied with a growing number of tasks, however, economic aspects are forcing us to search for unified solutions that do not require reengineering for every new or modified application. Therefore, the goal is to shift functionality from hardware to software. For example, channel selection and demodulation can be implemented as software codes and are no longer hardware realizations. These software-defined radios (SDRs), which compute classical receiver functions, can be reconfigurable. Therefore, the need for hardware solutions that can handle several standards and related software implementations arises. It is the purpose of this article to compare two very promising solutions (sampling and six-port) with respect to their suitability in the millimeter-wave range and to discuss some related research aspects.