Frequency-domain measurement of the millimeter wave indoor radio channel

Coherent wideband frequency-domain measurements of the complex frequency response of millimeter wave indoor radio channels are discussed. In addition, results of measurements performed in a 2 GHz band centered around 58 GHz will be presented. It is shown that a 40 dB dynamic range and a 400 ns aliasing-free range are sufficient for a correct estimation of the rms delay spread from the measurement dat

Characterisation of propagation in 60 GHz radio channels (invited)

Narrowband as well as wideband measurements have been performed in various indoor and outdoor environments in order to enable the development of reliable prediction models for 60 GHz radio channels. In addition, results of deterministic modelling on the basis of geometric ray-tracing have been compared with measurement results, showing that simple ray-tracing can be used to estimate both the narrowband and wideband characteristics of a 60 GHz radio channel. This paper reviews the measurement and modelling activities performed by various research institute

Bicnical horn antennas for uniform coverage in indoor areas at mm-wave frequencies

A method is presented for designing and dimensioning biconical horn antennas in such way that the level of received power does not depend strongly on the separation distance between a centralized base station and a remote radio terminal within an indoor pico-cell. Results of cell-coverage measurements at 58 GHz are presented using these antennas within eight different indoor environments. The measurement results show that, using biconical horn antennas, an overall uniform coverage can be achieved for both line-of-sight and obstructed line-of-sight topologie

Application of five-sector beam antenna for 60 GHz indoor wireless communications

The application of a switched five-sector beam antenna in high-speed indoor wireless LAN systems operating in the 60 GHz band is investigated. The effects of line-of-sight obstruction as well as the influence of the access-point antenna height are experimentally studied in a typical small-sized office room. The results are compared with those obtained with classical antenna configuration

Performance impact of IQ mismatch in direct-conversion MIMO OFDM transceivers

This contribution analytically studies the influence of transmitter (TX) as well as receiver (RX) IQ mismatch on the performance of multiple-antenna OFDM systems based on direct-conversion. Analytical expressions are derived for the probability of error for MIMO OFDM systems in both nonfaded and Rayleigh faded channels. The results can be used to derive matching specifications for the TX- and RX-branches. It is concluded that in fading channels RX IQ imbalance is on average more destructive than TX IQ imbalance. Additionally, it is concluded that the addition of extra RX antennas is beneficial to reduce RX IQ imbalance dependence, but increases the TX IQ imbalance impac

Application of fan-beam antennas for 60GHz indoor wireless communication

The application of fan-beam antennas in high-speed indoor wireless communication systems operating in the 60 GHz band is investigated. The effects of line-of-sight obstruction as well as antenna pointing deviation on the power link budget are experimentally studied in a typical laboratory environment. The results are contrasted with those obtained with alternative antenna configuration

Peak-to-average power reduction in space division multiplexing based OFDM systems through spatial shifting

A new method to reduce the peak-to-average power ratio (PAPR) in space division multiplexing systems applying orthogonal frequency division multiplexing is proposed. The method applies spatial shifting to partial transmit sequences to achieve a decreased PAPR on all transmit branches

Comments on "A shaped reflector antenna for 60-GHz indoor wireless LAN access points"

The author comments that the shaped reflector antenna principles and theory of Smulders, Khusial and Herben (see ibid., vol.50, p.584-91, Mar.2001) are based on the papers described by Kumar (see Proc. Montech '86 IEEE Conference on Antennas and Communication, 1986, IEEE Cat. No. TH0156-0, Inst. Elect. Eng. Proc., vol.134, p.106-108, 1987 and Technology Symposium, 1990). These papers described the X-band, circularly polarized shaped beam telemetry antenna suitable for retransmitting the radar data back to an earth terminal. Smulders et al. have used the same principle, and similar types of radiation patterns are produced. However, two points are different in their paper: (1) the design frequency (60 GHz) and (2) the application of antenna for indoor wireless LAN access points. Therefore, they authors should have referenced Kumar's papers. Smulders et al. agree with Kumar's comments that reflector shaping is nothing new. However, we took into account diffraction effects (by applying the uniform theory of diffraction) whereas the shaping in the paper of Kumar is based on geometrical optics, only. We showed that according to our approach, a more smooth illumination function can be achieved and how the smoothing effect depends on the amount of edge illumination. We also showed in which way the spatial field deviation can be minimized and that this could save a few decibels in the link budget