Programmers of parallel processes that communicate through shared globally distributed data structures (DDS) face a di cult choice. Either they must explicitly program DDS management, by partitioning or replicating it over multiple distributed memory modules, or be content with a high latency coherent (sequentially consistent) memory abstraction that hides the DDS' distribution. We present Merm...

In this contribution, we develop a (novel) family of Multiple-Input Multiple-Output (MIMO) UWB Impulse-Radio (UWB-IR) transceivers for Orthogonal PPMmodulated (OPPM) coded transmissions over (baseband) multipath-faded MIMO channels. To by-pass expensive channel-estimation procedures, the MIMO channel pathgains are assumed to be fully unknown at the receiver. Thus, according to the UWB-IR statis...

For turbo reception of coded transmissions over unknown doubly selective channels, such as time-varying ISI channels or frequency-varying ICI channels, we propose several soft noncoherent equalizers based on basis expansion (BE) channel modeling and tree-search, as a departure from traditional designs based on autoregressive (AR) channel modeling and/or trellis processing. By “noncoherent,” we ...

Wepresent a comparison between coherent and noncoherent UWB receivers, under a realistic propagation environment, that takes into account also the effect of path-dependent pulse distortion. As far as coherent receivers are concerned, both maximal ratio combining (MRC) and equal gain combining (EGC) techniques are analyzed, considering a limited number of estimated paths. Furthermore, two classi...

Abstract— Two different power-scaled noncoherent detection schemes are analyzed and compared in terms of detection probability and mean detection time in the uplink of a wideband CDMA system, where the mobile terminal transmits a pilot signal in the form of bursts of modulated chips, which are transmitted periodically and separated by long silent intervals. Both detection schemes employ tempora...

The optimum noncoherent multiuser detector is obtained for generalized diversity symbol-synchronous communication systems that employ nonorthogonal multipulse modulation. A unified approach is adopted to simultaneously address various forms of diversity such as time, frequency, multipath, and/or receiver–antenna diversity. Upper and lower bounds on the average bit-error probability of the optim...

Fourier analyzer concept that generalize the waveform communications to include chaotic carriers can be used to discuss and optimize detection problems. Using this new description it is possible to develop new detector configurations with improved performance for chaotic communications that may be used in ultra-wideband radio (UWB). Radio communications via channels already occupied by traditio...

Given the dense multipath propagation in typical ultra-wideband channels, traditional coherent receivers may become computationally complex and impractical. Recently, noncoherent UWB architectures have been motivated with simple implementations. Nevertheless, the rudimentary statistical assumption and practical information uncertainty inevitably results in a hardly optimistic receiving performa...