The IRC radio channel measurement system has been developed to enable multidimensional channel measurements for different purposes. The number of channels has been extended to 64 at the 2 GHz frequency band, and 32 at the 5 GHz band. A dual-polarized microstrip patch antenna element has been developed for measurement purposes. A fast data acquisition unit has been designed to allow measurements of long continuous mobile routes with antenna arrays [9]. A data acquisition unit with similar design is currently under construction.
Other people involved:
Pauli Aikio, Ralf Grüber, Eino Kahra, Jarmo Kivinen, Matti Leppänen, Jani Ollikainen,
Martti Toikka, Pertti Vainikainen, Veli Voipio, Lasse Vuokko
Measurements of the time-variant radio channel of a moving mobile in a suburban environment have been performed at the base station site using a linear 8-element antenna array [1,2]. The measured channels have been analyzed in terms of the instantaneous delay and azimuth spread over the mobile routes. The routes included transients between LOS and NLOS, and the results demonstrate the effect of transients on the spatial and temporal channel properties. The correlation between the delay and angular spread of the channel is found to be high, with a correlation coefficient of approximately 0.85. The frequency correlation of the channel is analyzed using the wideband measurement signal. The frequency correlation coefficient at ±15 MHz off the center frequency varies from 0.5 to 0.7, depending on the mobile route. In addition, the correlation of the channel at the BS is studied as a function of distance between the elements in the array. The correlation coefficient between the ends of the array (3.5 l) separation is approximately 0.7 [10].
Other people involved:
Pauli Aikio, Eino Kahra, Petri Karttunen, Jarmo Kivinen, Hassan El Sallabi, Pertti
Vainikainen
A real-time measurement method has been developed to determine the angular 3D signal distribution at the mobile station [3,5]. The properties of the measurement include 40° angular resolution, 17 dB cross polarization discrimination, and 12 dB spatial dynamic range. The measurement is very fast, and thus enables the collection of statistically significant amounts of data, as well as the characterization of the time-variant channel behavior, e.g. transients. Measurements have been performed in different environments to characterize the elevation power distribution and cross-polarization power ratio at the mobile terminal. The information is essential in evaluating antennas of mobile handsets in realistic environments. Four different types of environments have been measured: indoor microcell, urban microcell, suburban microcell, and suburban macrocell. According to the measurements, the elevation power distribution varies heavily depending on the propagation conditions such as building height and material. There is no significant difference in the elevation power distributions for vertical and horizontal polarizations, when vertical polarization is transmitted. Only the LOS peaks can be clearly identified in the power at vertical polarization [4,8]. More measurements will be performed during 2000 to obtain statistical significance.
Other people involved:
Arnaud Brehonnet (NRC), Eino Kahra, Heikki Laitinen (VTT), Viktor Nässi, Kari Skog (NRC),
Martti Toikka, Pertti Vainikainen, Leo Vaskelainen (VTT), Lasse Vuokko
A novel 3D high-resolution measurement method has been developed for the base station, to investigate the propagation mechanisms in urban environments at 2 GHz. The achieved angular resolution with the used DoA estimation algorithm is approximately 1° in azimuth and 2° in elevation domains [6]. The cross polarization discrimination is 18 dB. Measurements at three different BS sites with different antenna heights in urban environment have been performed. The results show that the urban radio channel has a very strong directional nature, where the incoming energy is mainly concentrated in spatial clusters. The surroundings of the mobile have only minor effect on the clusters seen by the BS, independently of the antenna height [6,7].
Other people involved:
Klaus Hugl (TuWien), Eino Kahra, Juha Laurila (TuWien), Viktor Nässi, Martin Toeltsch
(TuWien), Martti Toikka, Pertti Vainikainen, Lasse Vuokko