Low-Cost Transceiver Architectures for 60 GHz Ultra Wideband WLANs

Millimeter-wave multiport transceiver architectures dedicated to 60 GHz UWB short-range communications are proposed in this paper. Multi-port circuits based on 90° hybrid couplers are intensively used for phased antenna array, millimeter-wave modulation and down-conversion, as a low-cost alternative to the conventional architecture. This allows complete integration of circuits including antennas, in planar technology, on the same substrate, improving the overall transceiver performances

Multichannel Online Blind Speech Dereverberation with Marginalization of Static Observation Parameters in a Rao-Blackwellized Particle Filter

Room reverberation leads to reduced intelligibility of audio signals and spectral coloration of audio signals. Enhancement of acoustic signals is thus crucial for high-quality audio and scene analysis applications. Multiple sensors can be used to exploit statistical evidence from multiple observations of the same event to improve enhancement. Whilst traditional beamforming techniques suffer from interfering reverberant reflections with the beam path, other approaches to dereverberation often require at least partial knowledge of the room impulse response which is not available in practice, or rely on inverse filtering of a channel estimate to obtain a clean speech estimate, resulting in difficulties with non-minimum phase acoustic impulse responses. This paper proposes a multi-sensor approach to blind dereverberation in which both the source signal and acoustic channel are directly estimated from the distorted observations using their optimal estimators. The remaining model parameters are sampled from hypothesis distributions using a particle filter, thus facilitating real-time dereverberation. This approach was previously successfully applied to single-sensor blind dereverberation. In this paper, the single-channel approach is extended to multiple sensors. Performance improvements due to the use of multiple sensors are demonstrated on synthetic and baseband speech examples

Accurate BER of MC-DS-CDMA over Rayleigh Fading Channels

In this paper, we derive an accurate average bit error rate (BER) of Rayleigh faded MC-DS-CDMA in the context of asynchronous transmission and random spreading sequences. The analysis is based on the characteristic function, and does not resort to any assumption on the statistical behavior of the interference. We develop a new closed-form expression for the conditional characteristic function of the inter-carrier interference and a single integration for the BER calculation. The accuracy of the standard Gaussian approximation (SGA) method is also evaluated. Keywords: multi-carrier direct-sequence CDMA (MC-DS-CDMA), performance evaluation, characteristic functio