This paper describes the topic and participants of the MDM 2013 panel.

We present a statistical analysis of wideband three-dimensional channel measurements at base station locations in an urban environment. Plots of the received energy over azimuth, elevation, and delay planes suggest that the incident waves group to clusters in most measured transmitter positions. A super-resolution algorithm (Unitary ESPRIT) allows one to resolve individual multipath components in such clusters and hence enables a detailed statistical analysis of the propagation properties. The origins of clusters-sometimes even individual multipath components-such as street apertures, large buildings, roof edges, or building corners can be localized on the city map. Street guided propagation dominates most of the scenarios (78%-97% of the total received power), while quasi-line-of-sight over-the-rooftop components are weak(3%-13% of the total received power). For this measurement campaign, in 90% of the cases, 75% of the total received power is concentrated in the two strongest clusters, but only 55% in the strongest one. Our analysis yields an exponential decay of power with 8.9 dB//spl mu/s, and a standard deviation of the log-normally distributed deviations from the exponential of 9.0 dB. The power of cross-polarized components is 8 dB below copolarized ones on average (vertical transmission).

We propose a semi-blind algorithm for smart antennas that, in addition to some structural signal properties, utilises user identifiers that are available in existing cellular systems. Our algorithm estimates, first, the row span of the adequately composed data matrix and then projects the obtained basis vectors iteratively to the finite alphabet (FA) constellation. We call the projection part of our algorithm DILSF (decoupled iterative least-squares with subspace fitting). Assuming two co-channel users in a GSM-like TDMA system and a Rayleigh fading channel with finite angular spread, we obtained a BER<10/sup -3/ with only 3 antennas, spaced 10/spl lambda/ apart. We also demonstrate that co-channel signals are resolvable even if they are not separable in angle. We gain a factor of up to 70 in computational complexity by employing subspace tracking algorithms and demonstrate the robustness of the method against array imperfections.