Standardization work for MIMO OTA testing methods is currently ongoing, where a multi-probe anechoic chamber based solution is an important candidate. In this paper, the probes located on an OTA ring are used to synthesize a plane wave field in the center of the OTA ring. This paper investigates the extent to which we can approach the synthesized plane wave in practical measurement systems. Both single plane wave with certain AoA and multiple plane waves with different AoAs and power weightings are synthesized and measured. Deviations of the measured plane wave and the simulated plane wave field are presented in terms of phase and power. Possible reasons for the deviations are also investigated.

Long haul transport can be considered an obvious deployment scenario for communication between vehicles travelling in convoy, where environments will be comparable to that of a rural highway. Therefore this paper addresses antenna array techniques applicable to such circumstances, which provide little scattering to the propagation channel and little support for diversity. Only beamforming is realistically suited to increase the capacity in the vehicle to vehicle link. However, the possibility to enable multi user channels is limited in such environments since the propagation channels are highly correlated when more than two vehicle to vehicle links are in close proximity. The deliberate introduction of delay spread through wide spaced and combined multiple antenna topology thus creating an artificial wideband fading channel is proposed in this paper, which results in de-correlated vehicle to vehicle links. Measurements and experimental results are presented that demonstrate the means by which uncorrelated wideband channels between separate vehicle to vehicle links can be formed to enable multi user capabilities specific to vehicles on a rural highway.

Preliminary results on the use of the vehicle to vehicle MIMO channel in a rural highway environment are presented. This is looked at both in terms of the available spatial multiplexing through singular value decomposition and also angular distribution within the channel. Results indicate a strong predominant line of sight link in general while instances of scattering from other vehicles will cause changes in the Doppler spectrum as well as beamforming jitter.

Outdoor radio propagation experiments are presented at 2.4 GHz, using a handset MIMO antenna with two monopoles and two planar inverted-F antennas (PIFAs), adjacent to a human phantom in browsing stance. The propagation test was performed in an urban area of a city, which resulted in non line-of-sight (NLOS) situations. In our investigation, the 4-by-4 MIMO and SISO channel capacities for the reception signals were evaluated. These measurements show that the handset MIMO antenna, close to the human operator, is capable of MIMO reception.

We obtained results on the capacity of a mobile MIMO channel and on the influence of the user. Measurements were done in a configuration with three distributed transmitters equipped with single antennas and with a small wireless handset with four antennas, creating a 4Rx /spl times/ 3Tx configuration. We express the quality of the radio channel in terms of the effective degree of freedom (EDOF). From our measurement it follows that fitting a small handset with multiple antennas still makes sense in an outdoor-to-indoor mobile MIMO scenario. The channel capacity can be excellent, comparable with fully uncorrelated Rayleigh fading branch signals. However, on average the user should be satisfied with less favourable conditions amounting to a loss in EDOF of 0.16 at 50% complementary cumulative distribution function (CCDF) level. Systems operating without power control will suffer from an extra degradation in EDOF of 0.10 with an increased spread in channel quality both at the high and low end of the EDOF curve.

Attaching cables to mobile terminals for accurate measurements is progressively influencing the radiation characteristics with the diminishing size of the terminals. Simulations show the large influence of cables and their exact curvature on the radiation properties of mobile terminals that are small with respect to the wavelength. These results are confirmed by measurements in an anechoic chamber. As corrections for these almost irreproducible influences are hardly feasible, we propose to omit conducting cables completely. Instead, optical fibres are used for transparent transport of the RF signals. Off-the-shelf system components allow for two channels in a box of size comparable to modern small terminals. When driven at an appropriate level this set-up shows ample dynamic range for mobile radio channel sounding.

This paper describes radio channel and BER investigations performed in various scenarios typical to the TETRA direct mode operation (DMO), in a forest area. The data from radio channel sounding measurements was analysed in terms of average fade duration and envelop CDF. The same data was used to evaluate the unprotected BER on a TETRA communication link. The BER level distribution was compared to the distribution obtained when simulating a pedestrian speed TETRA DMO radio channel. The dynamics of the mobiles can have a strong influence on the radio link quality. As a general tendency, higher practical BER values can be expected as compared to the simulations when using the simple TETRA radio channel model.

This paper shows the results for a direction of arrival (DOA) algorithm, which is designed for downlink beamsteering in a GSM related system. Measurement campaigns have been conducted for an 8 element adaptive antenna array in an urban environment. The results using measurement data indicate that an averaging window size of one SACCH frame (0.48s) is a wise choice for DOA estimation in a non-FH network or a FH network using DTX. Downlink beamsteering performance is analysed for different antenna array configurations and different number of fixed beam directions. The performance evaluations are made for both the measured data and data obtained from simulations.

This paper gives a description of a hardware testbed for evaluation of adaptive base station antenna arrays in the GSM/UMTS. The testbed is aimed at the spatial and temporal characterisation of the radio channel and at the performance evaluation of array processing algorithms. The testbed consists of two test mobiles and an 8 element adaptive array receiver. The array processing is implemented by means of real-time digital signal processing hardware.