834 research outputs found
28 GHz and 73 GHz Millimeter-Wave Indoor Propagation Measurements and Path Loss Models
This paper presents 28 GHz and 73 GHz millimeter- wave propagation
measurements performed in a typical office environment using a 400
Megachip-per-second broadband sliding correlator channel sounder and highly
directional steerable 15 dBi (30 degrees beamwidth) and 20 dBi (15 degrees
beamwidth) horn antennas. Power delay profiles were acquired for 48
transmitter-receiver location combinations over distances ranging from 3.9 m to
45.9 m with maximum transmit powers of 24 dBm and 12.3 dBm at 28 GHz and 73
GHz, respectively. Directional and omnidirectional path loss models and RMS
delay spread statistics are presented for line-of-sight and non-line-of-sight
environments for both co- and cross-polarized antenna configurations. The LOS
omnidirectional path loss exponents were 1.1 and 1.3 at 28 GHz and 73 GHz, and
2.7 and 3.2 in NLOS at 28 GHz and 73 GHz, respectively, for
vertically-polarized antennas. The mean directional RMS delay spreads were 18.4
ns and 13.3 ns, with maximum values of 193 ns and 288 ns at 28 GHz and 73 GHz,
respectively.Comment: 7 pages, 9 figures, 2015 IEEE International Conference on
Communications (ICC), ICC Workshop
Wideband performance comparison between the 40 GHz and 60 GHz frequency bands for indoor radio channels
When 5G networks are to be deployed, the usability of millimeter-wave frequency allocations seems to be left out of the debate. However, there is an open question regarding the advantages and disadvantages of the main candidates for this allocation: The use of the licensed spectrum near 40 GHz or the unlicensed band at 60 GHz. Both bands may be adequate for high performance radio communication systems, and this paper provides insight into such alternatives. A large measurement campaign supplied enough data to analyze and to evaluate the network performance for both frequency bands in different types of indoor environments: Both large rooms and narrow corridors, and both line of sight and obstructed line of sight conditions. As a result of such a campaign and after a deep analysis in terms of wideband parameters, the radio channel usability is analyzed with numerical data regarding its performance
Experimental study of MIMO-OFDM transmissions at 94 GHz in indoor environments
Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28, 38and 60 GHz bands ─in both indoor and short-range scenarios─,only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this work is to study the viability and evaluate the performance of the 94 GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.This work was supported in part by the Ministerio de Economía y Competitividad MINECO, Spain under Grant TEC2016-78028-C3-2-P, and in part by the European FEDER funds
An Efficient Uplink Multi-Connectivity Scheme for 5G mmWave Control Plane Applications
The millimeter wave (mmWave) frequencies offer the potential of orders of
magnitude increases in capacity for next-generation cellular systems. However,
links in mmWave networks are susceptible to blockage and may suffer from rapid
variations in quality. Connectivity to multiple cells - at mmWave and/or
traditional frequencies - is considered essential for robust communication. One
of the challenges in supporting multi-connectivity in mmWaves is the
requirement for the network to track the direction of each link in addition to
its power and timing. To address this challenge, we implement a novel uplink
measurement system that, with the joint help of a local coordinator operating
in the legacy band, guarantees continuous monitoring of the channel propagation
conditions and allows for the design of efficient control plane applications,
including handover, beam tracking and initial access. We show that an
uplink-based multi-connectivity approach enables less consuming, better
performing, faster and more stable cell selection and scheduling decisions with
respect to a traditional downlink-based standalone scheme. Moreover, we argue
that the presented framework guarantees (i) efficient tracking of the user in
the presence of the channel dynamics expected at mmWaves, and (ii) fast
reaction to situations in which the primary propagation path is blocked or not
available.Comment: Submitted for publication in IEEE Transactions on Wireless
Communications (TWC
3-D Statistical Channel Model for Millimeter-Wave Outdoor Mobile Broadband Communications
This paper presents an omnidirectional spatial and temporal 3-dimensional
statistical channel model for 28 GHz dense urban non-line of sight
environments. The channel model is developed from 28 GHz ultrawideband
propagation measurements obtained with a 400 megachips per second broadband
sliding correlator channel sounder and highly directional, steerable horn
antennas in New York City. A 3GPP-like statistical channel model that is easy
to implement in software or hardware is developed from measured power delay
profiles and a synthesized method for providing absolute propagation delays
recovered from 3-D ray-tracing, as well as measured angle of departure and
angle of arrival power spectra. The extracted statistics are used to implement
a MATLAB-based statistical simulator that generates 3-D millimeter-wave
temporal and spatial channel coefficients that reproduce realistic impulse
responses of measured urban channels. The methods and model presented here can
be used for millimeter-wave system-wide simulations, and air interface design
and capacity analyses.Comment: 7 pages, 6 figures, ICC 2015 (London, UK, to appear
UWB channel characterization in 28 ghz millimeter waveband for 5G cellular networks
The demands of high data rate transmission for future wireless communication technologies are increasing rapidly. The current bands for cellular network will not be able to satisfy these requirements. The millimeter wave (mm-wave) bands are the candidate bands for the future cellular networks. The 28 GHz band is the strongest candidate for 5G cellular networks. The large bandwidth at this band is one of the main parameters that make the mm-wave bands promising candidate for the future cellular networks. To know the wideband channel behavior in mm-wave bands, the wideband channel characterizations are required. In this paper, the 3D WINNER model is used to model the wideband channel at 28 GHz band. Based on this model, the time dispersion parameters at 28 GHz mm-wave band are investigated. The root mean square delay spread and the mean excess delay are the main parameters that can be used to characterize the wideband channel. Morever, the cumulative distribution function (CDF) is used to model the RMS delay spreads. The results show that the RMS delay spread varies between 4.1 ns and 443.7 ns
Investigation of Prediction Accuracy, Sensitivity, and Parameter Stability of Large-Scale Propagation Path Loss Models for 5G Wireless Communications
This paper compares three candidate large-scale propagation path loss models
for use over the entire microwave and millimeter-wave (mmWave) radio spectrum:
the alpha-beta-gamma (ABG) model, the close-in (CI) free space reference
distance model, and the CI model with a frequency-weighted path loss exponent
(CIF). Each of these models have been recently studied for use in standards
bodies such as 3GPP, and for use in the design of fifth generation (5G)
wireless systems in urban macrocell, urban microcell, and indoor office and
shopping mall scenarios. Here we compare the accuracy and sensitivity of these
models using measured data from 30 propagation measurement datasets from 2 GHz
to 73 GHz over distances ranging from 4 m to 1238 m. A series of sensitivity
analyses of the three models show that the physically-based two-parameter CI
model and three-parameter CIF model offer computational simplicity, have very
similar goodness of fit (i.e., the shadow fading standard deviation), exhibit
more stable model parameter behavior across frequencies and distances, and
yield smaller prediction error in sensitivity testing across distances and
frequencies, when compared to the four-parameter ABG model. Results show the CI
model with a 1 m close-in reference distance is suitable for outdoor
environments, while the CIF model is more appropriate for indoor modeling. The
CI and CIF models are easily implemented in existing 3GPP models by making a
very subtle modification -- by replacing a floating non-physically based
constant with a frequency-dependent constant that represents free space path
loss in the first meter of propagation.Comment: Open access available at:
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=743465
THZ RF measurement techniques
Abstract. In this thesis, literature review on available methods, techniques and procedures for terahertz antenna measurement system and terahertz propagation measurement system are reported. The paper presented the terahertz frequency spectrum allocation by FCC, ITU, ETSI and its application in wireless communication system with advantage in obtaining terabits per second data rates. Terahertz antenna parameters are reported and measurement systems for measurement of these chapters are reviewed.
Literature of three papers on terahertz antenna measurement system with their respective measurement setup, calibration techniques and measurement procedures are reviewed. An automated antenna measurement system is reviewed with stochastic and systematic measurements and has achieved terahertz antenna s-parameter measurements in far field region at frequency range of 220 GHz to 330 GHz. Another measurement system with single port short-open-load (SOL) calibration technique is reviewed. In this measurement of s-parameter of terahertz antenna is carried out, using receiver horn placed on 3 D positioner, which records the AUT 3D radiation pattern. The third paper reviewed, is a reconfigurable terahertz antenna measurement system, with capabilities of working on large bandwidths, with small change in work bench instrumentation. This setup contains the multiplexing stages for terahertz frequency generation. Beam pattern measurements are conducted at 1.37 THz supporting the simulations and the system stability for reconfigurations.
In the later study, terahertz propagation parameters are studied and presented for review of available terahertz propagation measurement systems. Literature review of three papers describing different setup and procedures for terahertz propagation measurement system are reported. The first system with the setup to record path loss in LOS and NLOS links at 260 GHz to 400 GHz is presented. Propagation parameters containing reflections, shadowing is measured. LOS and NLOS channel capacity models are obtained based on data rates in terabits per second for using above 5G wireless communication systems. Another system with office architecture, indoor LOS link, viable for indoor wireless communication applications is reported. Propagation parameters containing power density profile (PDP) are measured and validated for 140 GHz to 220 GHz. A measurement system which reports effect of atmospheric pressure, temperature and humidity is reported in the last. The setup used short, offset-short, load and thru (SOLT) technique for calibration and PDP propagation parameter is measured for 0.5 THz to 0.75 THz.
Terahertz antenna and wave propagation measurement system reviewed in the papers are vital for development of terahertz systems in wireless and mobile communication. Further the study can be extended for measurement of terahertz antennas and wave propagation parameters with models of use in wireless hand-held devices, connected devices, mobile backhaul system and more
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