New digital signal-Processing approach for transmitter measurements in third generation Telecommunications systems

The rapid growth of third generation (3G) telecommunications systems has created the need for getting new test equipment as well as getting measurement techniques up and running in a very short time. Trying to satisfy this exigency, a new measurement method for testing 3G transmitters is proposed here. Thanks to the use of time-frequency distributions, the method provides a unified approach for carrying out, automatically and in a very straightforward manner, most measurements needed to fulfill the aforementioned task. After a brief outline of 3G technology basics, some details concerning transmitter tests are given. The fundamental steps of the proposed method are then described with references to a clarifying example, also highlighting advantages with respect to other measurement solutions. At the end, the performance of the method is assessed by means of several experiments on both simulated and emulated signals.     

Power measurement in digital wireless communication systems through parametric spectral estimation

Power measurement in digital wireless communication systems often suffers from poor repeatability, usually accompanied by a low accuracy. To face the problem, the use of parametric spectral estimators is investigated in this paper. In particular, a new method is proposed, which first estimates the power spectral density (PSD) of the analyzed signal through Burg's solution, and then evaluates the power by applying straightforward measurement algorithms to the estimated PSD. The results of a number of experiments, carried out on both laboratory and actual signals peculiar to digital wireless communication systems, assess the efficacy and reliability of the method. Moreover, a comparison of the achieved performance to that offered by an alternative measurement solution, already proposed by the authors and based on nonparametric PSD estimation, shows that the method allows for a significant reduction of measurement time, while exhibiting the same repeatability.     

On the Suitability of GRID Service Technology for Distributed Measurements Based on Complex Digital Signal Processing Algorithms

Digital signal processing algorithms are nowadays playing an increasingly more important role in most measurement processes. Furthermore, in the presence of poorly digitized data, reliable and repeatable measurement results can often be assured by complementing the adopted procedure with a suitable processing stage. The realization of a ldquocollectionrdquo of measurement algorithms to be shared among researchers and technicians who work on similar topics should, thus, be advisable. Complex algorithms, however, suffer from critical drawbacks, in terms of computational burden and hardware resources, when applied to very long acquired records. The authors suggest the adoption of GRID Service as an innovative solution to provide researchers with a ldquocollectionrdquo of measurement algorithms and concurrently overcome the cited drawbacks. GRID Service is a new hardware/software approach that is capable of merging the higher computational performance of parallel GRID computing with key mechanisms and standards of Web service. It would be very possible to migrate complex measurement algorithms into services that are available and accessible on the Internet. As an application example, the authors present a GRID service mandated to power measurement in digital wireless communication systems.     

Performance measurement of IEEE 802.11b-based networks affected by narrowband interference through cross-layer measurements

Researches and development efforts in wireless networking and systems are progressing at an incredible rate. Among them, measurement and analysis of performance achieved at network layer and perceived by end users is an important task. In particular, recent advances concerning IEEE 802.11b-based networks seem to be focused on the measurement of key parameters at different protocol levels in a cross-layered fashion, because of their inherent vulnerability to in-channel interference. By adopting a cross-layer approach on a real network set-up operating in a suitable experimental testbed, packet loss against signal-to-interference ratio in IEEE 802.11b-based networks is hereinafter assessed. Results of several measurements aimed at establishing the sensitivity of IEEE 802.11b carrier sensing mechanisms to continuous interfering signals and evaluating the effects of triggered interference on packet transmission.     

Internet Protocol Packet Delay Variation measurements in communication networks: How to evaluate measurement uncertainty?

Measurement of Quality of Service (QoS) parameters is a relevant task in communication networks. Similarly to other contexts, the measurement result has to be completed with the related uncertainty in order to provide information about the significance and reliability of the overall measurement process. This aspect is particularly crucial in communication networks. In fact, the measured values of QoS parameters have often to be compared against suitable thresholds to check their compliance with required quality constraints (QoS levels delivered to the user are generally offered for a fee) or to reliably verify the effect of new services conveyed by the network on its performance.     

A FPGA-based instrument for power measurement in DVB-T systems

This paper deals with the implementation of an innovative measurement instrument for power measurement in Digital Video Broadcasting Terrestrial (DVB-T) systems.     

Unscented transform: a powerful tool for measurement uncertainty evaluation

An original approach for uncertainty evaluation in indirect measurements is presented hereinafter. The approach applies the unscented transform to the measurement model (i.e., the functional relationship between output and input quantities) in order to gain a reliable estimate of output expectation and standard deviation (measurement uncertainty). Thanks to some useful properties of the transform, notable limits of the current GUM recommendations can be overcome. In particular, reliable estimates are also granted in the presence of nonlinear and/or nonanalytical measurement models or complex digital signal processing algorithms. A number of numerical tests are conducted on simulated and actual measurement data. Remarkable concurrence between obtained estimates and those granted by Monte Carlo simulations confirms the efficacy of the proposed approach.     

Measurement of processing and queuing delays introduced by an open-source router in a single-hop network

Measurement of the main contributions to the single-hop delay introduced by an open-source router is dealt with. A new method is proposed, which is capable of distinguishing the time interval during which a generic packet stays in either input or output queue (queuing delay) of the router under analysis and the time interval characterizing the effective routing process (processing delay) the packet undergoes. Thanks to proper measurement probes, i.e., kernel-layer functions, the method makes the occurring time of events of interest available at the application layer, thus giving the possibility of separately evaluating the aforementioned delays and, ultimately, pursuing a deeper insight of the considered router. After brief remarks concerning various delays a packet experiences when passing through a generic router, the measurement principle underlying the method is presented in detail. Particular emphasis is put on its capability of locally monitoring the transit of each packet from the input to the output port of an open-source router along with main features and implementation issues of the proposed measurement probes. Results obtained in many experiments carried out on a suitable test bed in different operating conditions are then given in order to highlight the method's reliability and effectiveness.     

CDK4, CDK6/cyclin-D1 Complex Inhibition and Radiotherapy for Cancer Control: A Role for Autophagy

The expanding clinical application of CDK4- and CDK6-inhibiting drugs in the managements of breast cancer has raised a great interest in testing these drugs in other neoplasms. The potential of combining these drugs with other therapeutic approaches seems to be an interesting work-ground to explore. Even though a potential integration of CDK4 and CDK6 inhibitors with radiotherapy (RT) has been hypothesized, this kind of approach has not been sufficiently pursued, neither in preclinical nor in clinical studies. Similarly, the most recent discoveries focusing on autophagy, as a possible target pathway able to enhance the antitumor efficacy of CDK4 and CDK6 inhibitors is promising but needs more investigations. The aim of this review is to discuss the recent literature on the field in order to infer a rational combination strategy including cyclin-D1/CDK4-CDK6 inhibitors, RT, and/or other anticancer agents targeting G1-S phase cell cycle transition.