Testbed

About: Testbed is a research topic. Over the lifetime, 10858 publications have been published within this topic receiving 147147 citations. The topic is also known as: test bed.

Enhancement for content delivery with proximity communications in caching enabled wireless networks: architecture and challenges

Abstract: To cater for the exploding growth of video traffic, small cell base stations (SBSs) and deviceto- device-enabled caching and delivery have been regarded as promising techniques for future wireless networks. In this article, we design a proximity communications enhanced multilayer caching and delivery architecture. Then merits possessed by the proposed architecture are highlighted, and challenges and open issues are comprehensively presented. Specifically, we shed light on the trade-offs between key performance indicators (e.g., hit ratio, latency, and coverage) and operation costs (e.g., device storage space, wireless bandwidth, and device battery life), and then clarify fundamental coupling between content caching and delivery. To further verify the effectiveness of the cooperation among SBSs and user equipments, we propose a distributed content caching and delivery strategy, jointly considering popularity distribution, diverse storage capability, and user mobility. Simulation results demonstrate that the proposed strategy can significantly lower the content retrieval latency and reduce the traffic flowing to core networks. Furthermore, design details of the experimental testbed are presented, and the validity of our developed strategy is verified.

An eight-user time-slotted SPECTS O-CDMA testbed: demonstration and simulations

Abstract: This paper demonstrates an eight-user 9 Gb/s/user time-slotted spectral phase-encoded time-spreading (SPECTS) optical code division multiple access (O-CDMA) testbed. Experimentally measured performance is compared to numerical simulations. The testbed employs a novel compact fiber-pigtailed bulk-optics setup that utilizes a single two-dimensional (2-D) phase modulator for encoding multiple channels, each with a unique 64-chip Walsh code. The time-gated receiver is composed of a nonlinear optical loop mirror (NOLM) and a nonlinear thresholder each utilizing a highly nonlinear fiber (HNLF) as the nonlinear element. The testbed operates error free with up to six users and at a bit error rate BER<10/sup -9/ for eight simultaneous users. Careful modeling of each component in the testbed allows a close match between simulated and experimentally measured testbed performance.

Localization in wireless sensor networks

Abstract: Localization in wireless sensor networks: Classification and evaluation of techniquesRecent advances in technology have enabled the development of low cost, low power and multi functional wireless sensing devices. These devices are networked through setting up a Wireless Sensor Network WSN. Sensors that form a WSN are expected to be remotely deployed in large numbers and to self-organize to perform distributed sensing and acting tasks. WSNs are growing rapidly in both size and complexity, and it is becoming increasingly difficult to develop and investigate such large and complex systems. In this paper we provide a brief introduction to WSN applications, i.e., properties, limitations and basic issues related to WSN design and development. We focus on an important aspect of the design: accurate localization of devices that form the network. The paper presents an overview of localization strategies and attempts to classify different techniques. A set of properties by which localization systems are evaluated are examined. We then describe a number of existing localization systems, and discuss the results of performance evaluation of some of them through simulation and experiments using a testbed implementation.

Implementing a Cooperative MAC Protocol for Wireless LANs

Abstract: In wireless LANs that provide multi-rate support (IEEE 802.11a, 802.11b), stations that experience poor channel quality tend to use low transmission rates to reduce the bit-error-rate (BER) of each transmission. This phenomenon usually leads to a throughput fairness problem between the stations with good channel quality and those without. This fairness problem has been shown to result in throughput degradation for the whole network [8]. The MAC protocol proposed in [5] addresses this issue using an efficient cooperative scheme. Under this scheme, low rate stations are assisted by a high rate station, referred to as helper stations, in its transmissions. With such assistance, the low rate station will be able to transmit data at a higher rate in a two-hop manner using the helper station. We implemented this new protocol in a Linux testbed. This paper describes the assumptions, the implementation process and the challenges we were presented with. We evaluated the protocol using our testbed through experiments. The implementation of the protocol shows that it performs efficiently in supporting TCP applications.

A testbed for pedagogical requirements in algorithm visualizations

Abstract: Although algorithm visualizations have become numerous, they still have not been successfully adapted into mainstream computer science education. Algorithm visualization systems need to better address pedagogical requirements for effective educational use. We discuss the relevance of several such requirements that are not supported in most systems. The combination of two existing algorithm visualization systems implements these requirements and thereby provides a rich testbed for future studies of effectiveness.