A Statistical Spatio-Temporal Radio Channel Model for Large Indoor Environments at 60 and 70 GHz

Abstract

Millimeter-wave radios operating at unlicensed 60 GHz and licensed 70 GHz bands are attractive solutions to realize short-range backhaul links for flexible wireless network deployment. We present a measurement-based spatio-temporal statistical channel model for short-range millimeter-wave links in large office rooms, shopping mall, and station scenarios. Channel sounding in these scenarios at 60 and 70 GHz revealed that spatio-temporal channel characteristics of the two frequencies are similar, making it possible to use an identical channel model framework to cover the radio frequencies and scenarios. The sounding also revealed dominance of a line-of-sight and specular propagation paths over diffuse scattering because of weak reverberation of propagating energy in the scenarios. The main difference between 60 and 70 GHz channels lies in power levels of the specular propagation paths and diffuse scattering which affect their visibility over the noise level in the measurements, and the speed of power decay as the propagation delay increases. Having defined the channel model framework, a set of model parameters has been derived for each scenario at the two radio frequencies. After specifying the implementation recipe of the proposed channel model, channel model outputs are compared with the measurements to show validity of the channel model framework and implementation. Validity was demonstrated through objective parameters, i.e., pathloss and root-mean-square delay spread, which were not used as defining parameters of the channel model.Index Terms-Channel model, millimeter-wave, short-range communications.

E-band millimeter wave indoor channel characterization

“…Following the approach described in [13], [18], extended to the double-directional channel, the synthetic omnidirectional power delay profile (PDP) is then obtained as follows:…”

“…Rx). The number of detectable paths (N k ) and their corresponding delays τ k , (k = {1...N k }) is determined from the synthetic P DP p (τ ) by applying the path detection algorithm defined in [13]. The algorithm searches for local maxima in the synthetic omnidirectional PDP by comparison with the threshold function defined as:…”

Channel Models and Beamforming at Millimeter-Wave Frequency Bands

“…[88] complements the cluster parameters following the principle of the 11ad-model, and furthermore found that small fixtures such as ceiling lamps and shelfs are often visible as clusters, despite they are neglected for the sake of simplicity in the 11ad-model. As an alternative model, the papers [89], [90] characterize their measured PDPs as a combination of specular and diffuse components that appear as discrete spikes and continuously decaying power spectrum over delay, respectively. The diffuse spectrum behaves as if it was a noise floor, as commonly observed in PDPs at microwave frequencies [91].…”

“…In contrast, there are also works reporting PAS spread over wide angular range; [71] shows PAS of outdoor rooftop-to-ground channels at 28 GHz, revealing rich scattering even in LOS cases. The work [90] reports that radio channels in large indoor scenarios at 60 and 70 GHz show a uniform distribution of propagation paths over the azimuth angle, and that the path clustering phenomenon is not prevailing over the spatio-temporal domain.…”

“…Reported comparisons of channel characteristics at the mm-wave bands cover pathloss and delay spread with those measured at 2 GHz in office rooms [189], [190], 5 GHz in halls and meeting rooms [191], [192], 6.5 GHz in a car compartment [62], 17 GHz in an office building [193], [194] and in a car compartment [195], and finally with ultrawideband indoor channels [196], [197]. Comparison of channel characteristics parameters for different mm-wave frequency bands is reported in [27] for outdoor 38 and 60 GHz channels, [90] for indoor 60 and 70 GHz channels, and [21], [28] for 28 and 73 GHz in urban cellular channels. The papers tend to reveal that the equivalent omni-directional pathloss has similar pathloss exponents for mm-wave and microwave frequencies, and the main difference stems from the existence or absence of LOS that affects the initial pathloss.…”