An analytical statistical model for the RMS delay spread parameter in millimeter frequencies

1997 ◽  
Vol 18 (6) ◽  
pp. 1335-1351 ◽  
Author(s):  
G. A. Dimitrakopoulos ◽  
C. N. Capsalis
Keyword(s):  
Statistical Model ◽  
Delay Spread ◽  
Rms Delay Spread

scholarly journals PHY, MAC, and RLC Layer Based Estimation of Optimal Cyclic Prefix Length

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4796
Author(s):  
Adriana Lipovac ◽  
Vlatko Lipovac ◽  
Borivoj Modlic
Keyword(s):  
Error Recovery ◽  
Cyclic Prefix ◽  
Closed Form Expression ◽  
Delay Spread ◽  
Radio Link ◽  
Medium Access ◽  
Power Delay Profile ◽  
Rms Delay Spread ◽  
Industry Standard ◽  
New Radio

This work is motivated by growing evidence that the standard Cyclic Prefix (CP) length, adopted in the Long Term Evolution (LTE) physical layer (PHY) specifications, is oversized in propagation environments ranging from indoor to typical urban. Although this ostensibly seems to be addressed by 5G New Radio (NR) numerology, its scalable CP length reduction is proportionally tracked by the OFDM symbol length, which preserves the relative CP overhead of LTE. Furthermore, some simple means to optimize fixed or introduce adaptive CP length arose from either simulations or models taking into account only the bit-oriented PHY transmission performance. On the contrary, in the novel crosslayer analytical model proposed here, the closed-form expression for the optimal CP length is derived such as to minimize the effective average codeblock length, by also considering the error recovery retransmissions through the layers above PHY—the Medium Access Control (MAC) and the Radio Link Control (RLC), in particular. It turns out that, for given protective coding, the optimal CP length is determined by the appropriate rms delay spread of the channel power delay profile part remaining outside the CP span. The optimal CP length values are found to be significantly lower than the corresponding industry-standard ones, which unveils the potential for improving the net throughput.

The 5-GHz Airport Surface Area Channel—Part I: Measurement and Modeling Results for Large Airports

2008 ◽  
Vol 57 (4) ◽  
pp. 2014-2026 ◽  
Author(s):  
David W. Matolak ◽  
Indranil Sen ◽  
Wenhui Xiong
Keyword(s):  
Path Loss ◽  
Correlation Coefficients ◽  
Line Of Sight ◽  
Delay Spread ◽  
Rms Delay Spread ◽  
Amplitude Data ◽  
Amplitude Correlation ◽  
5 Ghz ◽  
Best Fit ◽  
Probability Density Function Pdf

We describe results from a channel measurement and modeling campaign for the airport surface environment in the 5-GHz band. Using a 50-MHz bandwidth test signal, thousands of power delay profiles (PDPs) were obtained and processed to develop empirical tapped-delay line statistical channel models for large airports. A log-distance path loss model was also developed. The large airport surface channel is classified into three propagation regions, and models are presented for each of the regions for two values of bandwidth. Values of the median root-mean-square (RMS) delay spread range from 500 to 1000 ns for these airports, with the 90 th percentile RMS delay spreads being approximately 1.7 ms. Corresponding correlation bandwidths (i.e., correlation value 1/2) range from approximately 1.5 MHz in non-line-of-sight (NLOS) settings to 17.5 MHz in line-of-sight (LOS) settings. Two types of statistical nonstationarity were also observed: 1) multipath component persistence and 2) propagation region transitions. We provide the multipath component probability of occurrence models and describe Markov chains that are used for modeling both phenomena. Channel tap amplitude statistics are also provided, using the flexible Weibull probability density function (pdf). This pdf was found to best fit fading tap amplitude data, particularly for frequently observed severe fading, which is characterized by fade probabilities that are worse than the commonly used Rayleigh model. Fading parameters equivalent to Nakagami-m-model values ofmnear 0.7 were often observed (withm= 1 being Rayleigh and m < 1 being worse than Rayleigh). We also provide channel tap amplitude correlation coefficients, which typically range from 0.1 to 0.4 but occasionally take values greater than 0.7.

scholarly journals Measurements of Building Transmission Loss and Delay Spread at 2.5 GHz

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
L. H. Gonsioroski ◽  
L. da Silva Mello
Keyword(s):  
Transmission Loss ◽  
Signal Transmission ◽  
Delay Spread ◽  
Dispersion Parameters ◽  
Rms Delay Spread ◽  
Urban Buildings ◽  
Time Dispersion ◽  
The Mean ◽  
Mean Excess Delay

This paper presents the results of measurements of signal transmission loss at 2.5 GHz through 10 urban buildings. This allows the characterization of different types of buildings by effective attenuation constants and consideration of the contribution of the transmitted signal in microcell coverage predictions. Power delay profiles (PDPs) of the received signal were also measured and used to determine the time dispersion parameters of the channel, including the mean excess delay and the rms delay spread.

scholarly journals Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Millimeter Wave Bands for 5G Cellular Communications

2018 ◽  
Vol 8 (4) ◽  
pp. 2254 ◽  
Author(s):  
Mohammed B. Majed ◽  
Tharek A. Rahman ◽  
Omar Abdul Aziz
Keyword(s):  
Communication Networks ◽  
Millimeter Wave ◽  
Wide Spectrum ◽  
Path Loss ◽  
Separation Distance ◽  
Propagation Path ◽  
Delay Spread ◽  
Propagation Time ◽  
60 Ghz ◽  
Rms Delay Spread

The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.

UWB CHANNEL CHARACTERIZATION IN 28 GHZ MILLIMETER WAVEBAND FOR 5G CELLULAR NETWORKS

2016 ◽  
Vol 78 (6-11) ◽  
Author(s):  
Ahmed M. Al-Samman ◽  
Tharek A. Rahman ◽  
Razali Ngah
Keyword(s):  
Cellular Networks ◽  
Cumulative Distribution ◽  
Delay Spread ◽  
Wave Band ◽  
Dispersion Parameters ◽  
Rms Delay Spread ◽  
High Data ◽  
Large Bandwidth ◽  
The Future ◽  
Wideband Channel

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.

scholarly journals Wideband and Ultrawideband Channel Models in Working Machine Environment

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Attaphongse Taparugssanagorn ◽  
Matti Hämäläinen ◽  
Jari Iinatti
Keyword(s):  
Exponential Decay ◽  
Radio Channel ◽  
Line Of Sight ◽  
Small Scale ◽  
Delay Spread ◽  
Confined Space ◽  
Rms Delay Spread ◽  
Decay Profile ◽  
Cabin Environment ◽  
Uwb Radio

We present statistical models for wideband and ultrawideband (UWB) radio channels in a working machine cabin environment. Based on a set of measurements, it was found that such a small and confined space causes mostly diffuse multipath scattering rather than specular paths. The amplitude of the channel impulse responses in the wideband case is mostly Rayleigh distributed small-scale fading signal, with only a few paths exhibiting Ricean distributions, whereas the ones in the UWB case tend to be log-normally distributed. For the path amplitude, we suggest an exponential decay profile, which has a constant slope in dB scale, with the corresponding parameters for the UWB case. For the wideband case, a twofold exponential decay profile provides excellent fits to the measured data. It was also noted that the root-mean-square (RMS) delay spread is independent of the line-of-sight/obstructed line-of-sight situations of the channel. The multipath components contributing significant energy play a major role in such a small environment if compared to the direct path. In addition, the radio channel gains are attenuated with the presence of a driver inside the cabin.

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