Amplitude Fading Statistics Research Articles

A Measurement-Based Model of BMI Impact on UWB Multi-Antenna PAN and B2B Channels

Personal area networks (PANs) and body-to-body (B2B) networks are of increasing importance for applications ranging from medical monitoring to entertainment. The performance of such networks is largely determined by the propagation channels in which they operate, and which in turn are strongly impacted by the human body/bodies in these channels. It is thus essential to quantify the impact of different body types/sizes on the channel characteristics for PAN and B2B channels. In this paper, we present an extensive propagation channel measurement campaign in the 2–10 GHz frequency band for SIMO (single-input-multiple-output) PAN and MIMO (multiple-input-multiple-output) B2B channels. The measurements were done using 60 (for PAN) and 9 (B2B) human subjects, which had widely varying body mass index (BMI) values grouped into three categories. For each BMI category, parameters such as the average path gain, shadowing gain, root-mean-squared delay spread, channel spatial correlation coefficients, amplitude fading statistics, and channel capacity values were extracted for both PAN and B2B channels. Our analysis reveals considerable differences between these parameters for different BMI categories.

Modeling the Ultra-Wideband Outdoor Channel: Model Specification and Validation

In this paper we establish a geometry-based stochastic ultra-wideband channel model for gas stations. We statistically describe the two-dimensional spatial location and power of clustered scatterers, and the shape of their visibility and shadowing regions. We also separately model the diffuse part of the impulse response (i.e., the part that cannot be explained by the scatterers' multipath components), and show that its amplitude fading statistics can be best described by a Weibull distribution with a delay dependent beta-parameter. A step-by-step implementation recipe demonstrates how the model can be built. Finally, we validate our model by comparing simulated and measured channel parameters such as the rms delay spread.

Efficacy of Multiband OFDM Approach in High Data Rate Ultra WideBand WPAN Physical Layer Standard using Realistic Channel Models

Multiband Orthogonal Frequency Division Multiplexing (MBOFDM) approach using UWB signals with short duration of pulses provide unique advantages in short-range high data rate wireless applications which include easy penetration through obstacles, high precision ranging and low processing power. In this paper a performance study on MB-OFDM is attempted for high data rate ultra wideband (UWB) WPAN physical layer standard according to modulation techniques such as QPSK, 16-QAM, 64-QAM etc. Different multipath components in the UWB channels are characterized by different delays and attenuation. The channel models chosen in simulation of MB-OFDM UWB communication system are different from standard UWB channels considering realistic multipath resolution and operating frequencies. In this research different amplitude fading statistics for UWB channel (IEEE 802.15.3a) are analysed. The BER performance of MB-OFDM UWB on modified UWB channel models are investigated through simulation study. It is observed that QPSK modulation for the MB-OFDM UWB system performs better than 16-QAM and 64-QAM in the CM3 (NLOS) and CM4 (NLOS) channel environment. We show that, at low data rate (55 Mbps) the MB-OFDM system performs better in the CM4 channel environment than in the CM3, CM2 and CM1 channel model due to its inherent frequency diversity. In high data rate (480 Mbps), the BER performance in CM1 channel model is found to be better than in CM2, CM3, CM4 channel model.

Performance Analysis of UWB Channels for Wireless Personal Area Networks

Ultra-wide band (UWB) communication is one of the most promising technology for high data rate networks over short-range communication. The ultra-wide bandwidth offers pulses with very short duration that provides frequency diversity and multipath resolution. Ultra-wide band (UWB) channels raise new effects in the receiver, the amplitude fading statistics being different compared to the conventional narrow band wireless channels. This review paper focuses on modeling of ultra-wide band channels, especially for simulation of personal area networks and also discusses the benefits, application potential and technical challenges in wideband communication. The concept of Orthogonal Frequency Division Multiplexing (OFDM) has recently been applied in wireless communication systems due to its high data rate transmission capability with high bandwidth efficiency and its robustness to multi-path delay. UWB OFDM communication was proposed for physical layer in the IEEE 802.15.3a standard which covers wideband communication in wireless personal area networks. Since the channel model for multicarrier UWB communication is different from that of plain ultra-wide band channel, a novel modification method in UWB channel model is proposed with specific center frequency and multipath resolution. Moreover, dynamic channel estimation is necessary before demodulation of UWB OFDM signals since the radio channel is time varying and frequency selective for wideband systems. The performance of the proposed method is statistically analyzed using LS and MMSE based channel estimation methods.

Performance Analysis of UWB Channels for Wireless Personal Area Networks

Ultra-wide band (UWB) communication is one of the most promising technology for high data rate networks over short-range communication. The ultra-wide bandwidth offers pulses with very short duration that provides frequency diversity and multipath resolution. Ultra-wide band (UWB) channels raise new effects in the receiver, the amplitude fading statistics being different compared to the conventional narrow band wireless channels. This review paper focuses on modeling of ultra-wide band channels, especially for simulation of personal area networks and also discusses the benefits, application potential and technical challenges in wideband communication. The concept of Orthogonal Frequency Division Multiplexing (OFDM) has recently been applied in wireless communication systems due to its high data rate transmission capability with high bandwidth efficiency and its robustness to multi-path delay. UWB OFDM communication was proposed for physical layer in the IEEE 802.15.3a standard which covers wideband communication in wireless personal area networks. Since the channel model for multicarrier UWB communication is different from that of plain ultra-wide band channel, a novel modification method in UWB channel model is proposed with specific center frequency and multipath resolution. Moreover, dynamic channel estimation is necessary before demodulation of UWB OFDM signals since the radio channel is time varying and frequency selective for wideband systems. The performance of the proposed method is statistically analyzed using LS and MMSE based channel estimation methods.

A generic statistical-based UWB channel model for high-rise apartments

A generic statistical-based ultrawide-band (UWB) indoor channel model which incorporates the clustering of multipath components (MPCs) is proposed. The model is derived using measurement data collected in the frequency band of 3-10 GHz in various types of high-rise apartment under different propagation scenarios. The measurement procedure allows the characterization of both the large-scale and the small-scale statistics of the channel. The main objective is to study multipath propagation behavior, particularly the phenomenon of clustered MPCs. The description of clustering observed in the channel uses two classes of parameters which characterize the clustering and the MPCs respectively. All parameters are described by a set of empirical probability density functions derived from the measured data such as the distribution of clusters and MPCs, cluster and MPC arrival statistics and small-scale amplitude fading statistics. A new distribution, namely, a mixture of two Poisson processes, is proposed to model the ray arrival times. This new distribution fits the empirical data better than the single Poisson process proposed in the conventional Saleh-Valenzuela (S-V) model. Analysis results show that the small-scale amplitude fading statistics are best modeled by the Weibull distribution. The Weibull b-shape parameter is lognormally distributed and is found to be invariant across the excess delay. Additionally, the temporal correlation between adjacent path amplitudes is investigated. The amplitude temporal correlation coefficients are found to be relatively small, and thus, can be assumed to be negligible in reality. The proposed model can provide a realistic simulation platform for UWB communication systems.

Channel Simulation for Optical Communication Systems

A technique is reported for simulating the signal fading that will be experienced by typical optical communication systems. The desired irradiance or amplitude fading statistics can be simulated by incorporating a linearized optical modulator subsystem between the transmitter and receiver. This technique has been implemented in the design and construction of a laboratory channel simulator. The design of the processing electronics is discussed along with the results of tests performed for each mode of operation.