P.F.M. Smulders

Statistical Characterization of 60-GHz Indoor Radio Channels

An extensive review of the statistical characterization of 60-GHz indoor radio channels is provided from a large number of published measurement and modeling results. First, the most prominent driver applications for 60 GHz are considered in order to identify those environment types that need to be characterized most urgently. Large-scale fading is addressed yielding path-loss parameter values for a generic 60-GHz indoor channel model as well as for the office environment in particular. In addition, the small-scale channel behavior is reviewed including the modeling of time-of-arrival and angle-of-arrival details and statistical parameters related to delay spread, angular spread and Doppler spread. Finally, some research directions for future channel characterization are given.

On the Design of Low-Cost 60-GHz Radios for Multigigabit-per-Second Transmission over Short Distances [Topics in Radio Communications]

This article reviews, discusses, and proposes crucial 60-GHz radio design options. First, it discusses the choice of integrated circuit technology for the radio frequency (RF) part and presents the status quo concerning standardization. Then, it describes the 60-GHz channel-propagation characteristics and proposes antenna solutions, as well as the architecture of the RF part, including a channelization scheme and frequency synthesizer architecture. With regard to the baseband part, we discuss the use of multicarrier modulation and compare it to single-carrier modulation. Finally, we demonstrate the consequences of the various design options as judged from link-budget calculations.

The threat of information theft by reception of electromagnetic radiation from RS-232 cables

Electromagnetic radiation arising from RS-232 cables may contain information which is related to the original RS-232 data signals. The seriousness of eavesdropping risks is shown by estimates of bit error rates feasible with a standard radio receiver as a function of the separation distance. In addition to this, results of experimental eavesdropping are presented.

In-House Networks Using Multimode Polymer Optical Fiber for Broadband Wireless Services

A novel system concept is presented to transport microwave signals over an in-house multimode graded-index polymer optical fiber network, in order to feed the radio access points in high-capacity wireless LANs. By employing optical frequency multiplying, the networks intrinsically limited bandwidth is overcome. The feasibility of this concept to carry data at several hundreds of Mbit/s speed for various microwave signal formats at carrier frequencies in the tens of GHz range is shown. The concept enables cost-effective system implementation, and easy upgrading by offering data signal transparency. It can readily be integrated with other system technologies such as wired Gigabit Ethernet in a single multi-service in-house polymer optical fiber network.

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 data. >

Frequency Selectivity of 60-GHz LOS and NLOS Indoor Radio Channels

This paper analyzes the frequency selectivity, which is caused by multipath effects, of indoor line-of-sight (LOS) and non-LOS (NLOS) channels based on channel measurements in the frequency band of 60 GHz. The coherence bandwidth is determined to characterize frequency selectivity figures of the channels employing the combination of omnidirectional, fan-beam and pencil-beam antennas at transmitter (TX) and receiver (RX) sides. The results quantitatively show how far directional configurations are more effective for combating multipath effect than the omnidirectional ones for LOS channels. The frequency selectivity of the fan-beam-to-fan-beam configuration is less sensitive to misaligned TX-RX beams than the fan-beam-to-pencil-beam one. In addition, when omnidirectional antennas are used at both TX and RX side, the frequency selectivity of a NLOS channel is less sensitive to the TX-RX height difference than that of a LOS channel. Moreover, coherence bandwidth is empirically related to root-mean-squared delay spread. Lastly, the results presented in this paper lead to some useful insights into antenna configurations and beamformer designs for a 60 GHz radio system

Deterministic modelling of indoor radio propagation at 40-60 GHz

Factors that influence the accuracy of high frequency models for indoor radio propagation at 40–60 GHz are identified and discussed. Simulation results obtained on the basis of Geometrical Optics are presented. The reliability of these results is examined by comparing them with those obtained from empirical measurements.

Wide-band measurements of MM-wave indoor radio channels

The results of wide-band measurements of indoor radio channels operating in a 2 GHz frequency band centered around 58 GHz are presented. The measurements were performed with a frequency step sounding technique. From the resulting frequency domain data base, cell coverage and time delay spread with both line-of-sight and obstruction of the direct path are derived. Eight indoor environments were subjected to propagation experiments. Since these areas are well defined and described the results can be readily related to other environments.<<ETX>>

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

This paper addresses the design of a 60-GHz shaped reflector antenna that has to illuminate a predefined circular area without substantial spatial variation. At the boundary of this coverage area, the field strength has to fall off rapidly. Such efficient and confined illumination may be required in wireless networks that have to cope with a stringent link budget and/or require low channel dispersion. Typical examples are the emerging broadband wireless networks for customer premises and residential applications that will operate in the millimeter-wave frequency region. The particular property of the considered reflector is its diverging surface instead of the commonly applied converging shape. It is shown that the spatial variation within the defined coverage area can be within 1 dB, provided that the antenna is perfectly constructed. It is also shown that practical imperfections such as axial and lateral feed displacement and mispointing of the feed on top of effects due to blocking by the feed can contribute to spatial field variations on the order of a few decibels.

A shaped reflector antenna for 60-GHz radio access points

A shaped reflector antenna for a prototype 60-GHz wireless LAN access point has been designed and constructed. Its performance has been verified through measurements of the antenna far-field radiation patterns in the compact antenna test range. Near-field patterns have been reconstructed from the measured far-field data by using the Hankel transform. The results show that the amplitude across the footprint area remains within 6 dB of uniformity.