Steen Leth Larsen

Bodyloss for handheld phones

Measurements in an anechoic room of three-dimensional radiation patterns for 44 test persons using a handheld phone with two antennas are investigated in order to find the bodyloss. The measured bodyloss range from 0.9 dB to 16 dB. From the measurements is was possible to separate the absorption and the loss due to mis-match of the antenna. The antenna mis-tuning accounted for less than 2 dB to the bodyloss. The uncertainties in the measurements is in the order of one dB.

Preliminary measurement results from an adaptive antenna array testbed for GSM/UMTS

This paper presents preliminary measurement results for an 8 element adaptive antenna array in an urban environment. The results show that in most cases the received signal consists of a single narrowly scattered component impinging from the direction towards the mobile. The angular spread (AS) is found to be no larger than 5 degrees for the test measurements. The correlation coefficient between slow fading and AS is -0.56, indicating that the AS increases when the local signal strength fades. The paper also shows the results for a direction of arrival (DoA) algorithm, which is designed for downlink beamsteering in a GSM related system. The results indicate that an averaging window size of one SACCH frame (0.48 s) is a wise choice for DoA estimation in a non-FH network.

A hardware testbed for evaluation of adaptive antennas in GSM/UMTS

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.

Algorithm test using measurements from an adaptive antenna array testbed for GSM/UMTS

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.