For mobile systems involving hand held devices, the influence of the user on system performance has to be considered. Extensive studies below 6 GHz have demonstrated large effects on system performance. However, the impact of user influence at potential higher frequency bands for upcoming 5G mobile networks is still to be investigated. This work investigates how the user affects the performance of a 5G handset mock-up. The user impact is studied by channel sounding in an indoor scenario, with and without the presence of different users. The mock-up handset has a uniform linear array of receive (Rx) antennas operated at 21.5 GHz. A dual-polarized horn antenna with a wide beamwidth is used as transmit (Tx) antenna and a fast channel sounder is used, allowing for recording dynamic and realistic channels. The results show that the mean influence of the user on the power varies considerably depending on the scenario, with more than 12 dB loss in some cases, while a gain of 4 dB is seen in other. An important finding is that the mean power among the seven Rx branches may be very different. Branch power ratios in the typical range of 2-10 dB were found, depending on the user and scenario.

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Abstract-In this paper, we propose a novel map-free indoor localization method using ultrawideband large-scale array systems in high frequency bands. The proposed localization method comprises two stages, namely a channel-estimation stage and a target-localization stage. Due to the large array aperture, the locations of the scatterers associated to the multipath components (MPCs) can be estimated with the spherical wavefront model. The estimated scatterers are further used as virtual anchors to estimate the location of the target through trilateration. Since the scatterer locations are obtained from channel measurements, the map of the environment is not needed for localization. The proposed method is also assessed with measurements conducted in a cluttered indoor environment with line-of-sight (LoS) and non-line-of-sight (NLoS) scenarios. Results show the proposed algorithm attains good localization accuracy in both scenarios.

Abstract-In this paper, we present validation of a method for constructing a virtual omnidirectional antenna in the azimuth plane. The virtual omnidirectional antenna utilizes a combination of data from directive horn antennas. The aim is to utilize the high gain of the horn antenna to improve the dynamic range of channel sounding measurements conducted in the centimeter and millimeter wave bands. The resulting complex impulse response from the virtual omnidirectional antenna is used to find the powerdelay-profile (PDP). This is then compared to measurements conducted at the same time using a real omnidirectional antenna. The validation shows that the synthesized omnidirectional is capable of predicting main components and the slope of the PDP. Further, it is shown that by choosing angular sampling steps corresponding to the half power beam width (HPBW) of the used antenna similar power levels can be achieved.

Abstract-With the future LTE auction for TV white spaces at 600 MHz, there is a strong need for efficient handset antennas operating at very low frequencies. This paper proposes a tunable antenna design for the low bands of LTE. In this design, not only the antenna is tuned but also the resonance of the board, thanks to using a tunable parasitic. The resulting dual-resonant antenna exhibits a peak total efficiency of -4 dB at 600 MHz.