This paper presents results of frequency domain measurements conducted to evaluate the effectiveness of frequency diversity in mitigating the effects of multipath fading in indoor microcellular channels employing omni-directional receive antenna in the band 63.4-65.4 GHz. The performance of frequency diversity for 155 MHz and other channel bandwidths to accommodate modulated signals with data rates up to 155 Mb/s is presented. Results are obtained using maximum selection combining and presented as functions of frequency separation between the diversity branch signals. Improvement in the level crossing rate and average fade duration is given together with improvement in the -Rician factor. The root mean square (rms) delay spread ( rms ) and coherence bandwidth ( c ) of the channel are also presented as functions of distance between terminals. Values of c for correlation levels of 0.9, 0.7, and 0.5 are given together with the cumulative distribution functions of rms . The levels below which the coherence bandwidth stays for 90% of receiver positions are estimated. Measurements were repeated under identical test conditions but with the receive omni-directional antenna replaced by a directional horn in order to characterize the effect of the receive antenna radiation pattern on the indoor radio channel characteristics.Index Terms-Coherence bandwidth, diversity, indoor channel, millimeter wave, radio-wave propagation, RMS delay spread, wireless LAN.

No abstract

No abstract

This paper introduces an efficient implementation of the Automatic Gain Control (AGC) for an IEEE 802.15.3c compliant receiver developed using a Field-Programmable Gate Arrays (FPGAs), both feed-forward and feed-backward AGCs are designed, implemented and evaluated.

Abstract-This paper presents results of frequency domain measurements conducted to characterize the distortionless transmission bandwidth (DTB) of indoor nonfading channels employing vertically and horizontally polarized antennas in the frequency band 63.4-65.4 GHz. The mean delay spread ( mean ), root mean square (rms) delay spread ( rms ), and the DTB of the channel are also presented as functions of distance between terminals and are compared for both polarizations. The dependence of DTB on the separation between terminals is modeled as DTB = where is a constant. mean increases linearly with , and its relationship with DTB is characterized as DTB = (1 mean ) + , where and are constants. The effectiveness of frequency and polarization diversity in mitigating the effects of multipath fading in indoor channels has also been evaluated. The performance of both diversity techniques when modulated signals with high data rates for multimedia applications are utilized is presented for maximum selection combining. The performance of frequency diversity is also shown as a function of frequency separation between diversity branch signals to determine whether an optimal frequency separation exists.