Propagation Properties of Radio Wave in Multipath Scattering Mobile Channel

1IntroductionAgoodunderstandingofthepropagationPropellesoftheurbanndcrocellularradiotransmissionchannelisveryimpo~tforthedesignofmobileradioandcordlesstelephonesystems.ThechannelbehaviorinurbanndcrocellsisdetenninedbyPropagationofrwhowavesinthetransmissionenvirolllnent.Typicalwavephenomenalikescattering,difhachon,andabsorphonbyPhysicalstIUctUresintheenvironmentSleadtoadiffusionofa~saltteddigitalsignalwaveintoacontinuousdistribuhonofpnalwaves.Obviously,theseeffeCtSdependonthegeometricalande…     

Correlation Bandwidth and Delay Spread Multipath Propagation Statistics for 910-MHz Urban Mobile Radio Channels

Distributions of delay spread and correlation bandwidth at 0.9 and 0.5 correlation for Gaussian wide-sense stationary uncorrelated scattering (GWSSUS) channels associated with 100 small-scale areas at different locations within a 2 × 2.5 km region of New York City are presented. For delay spread the maximum value observed was3frac{1}{2};mus and l0 percent of the areas exceeded2frac{1}{2}mus; for correlation bandwidth at 0.9 correlation the minimum was 20 kHz and 10 percent of the areas were less than 30 kHz; for correlation bandwidth at 0.5 correlation the minimum was 55 kHz and 10 percent of the areas were less than 130 kHz. The region is representative of the heavily built-up areas of many large cities in the United States.     

A Multipath Fading Simulator for Mobile Radio

A simple device to simulate the Rayleigh distributed fast fading encountered in mobile radio is described and evaluated. The Rayleigh envelope statistics are obtained by adding two independent Gaussian noise source in quadrature. The theoretical spectrum of the received signal is approximated by shaping the spectrum of the noise sources with filters. A design is given whose performance is shown to agree very closely with theory.     

多径衰落移动无线系统中的同频道干扰预测

同频道干扰是微蜂窝结构移动通信网所要考虑的一个核心问题，要想成功地对任何一种频率再用无线系统进行规划设计，就必须很好地了解并分析研究同频道干扰对系统性能的影响。本文对具有Ｎａｋａｇａｍｉ衰落和对数正态衰落的同频道干扰特性进行了理论分析，并提出了对微蜂窝多径衰落移动无线电系统中的同频道干扰及其影响进行预测的近似方法。     

Adaptive Equalization of High Capacity M-QAM Radio Systems on Multipath Fading Channels

In multilevel QAM radio systems affected by selective fading, countermeasures such as adaptive baseband equalization allow a drastic reduction of signatures. Linear and decision feedback equalization are investigated from an analytical and experimental point of view. The performance is evaluated and compared, dependence on accuracy of circuit implementation is analyzed, and simple asymptotic formulas describing the system behavior are given.     

Outage Analysis due to Multipath Mobile Radio Reception with Poisson Multiphath Arriva

The multipath self-interference (MSI) with Poisson multipath arrival is investigated in this paper. A number of scenarios are built around the statistical characterization of the magnitude of desired signal and the composite interfering signals, namely, Rayleigh/Rayleigh-Poisson, Rayleigh/Nakagami-Poisson, Nakagami/Nakagami-Poisson, and Rice/Nakagami-Poisson. It is shown that MSI can be statistically characterized in a similar manner as impulse or shot noise. The probability density function of the power ratio of desired to interfering signals is derived which is used to find the expressions for system outrage probability for the considered scenarios.     

Wide-Sense Stationarity of Mobile MIMO Radio Channels

Tests for the wide-sense stationarity (WSS) of multivariate random processes are developed and applied to measured multiple-input-multiple-output (MIMO) radio channel responses. Evolutionary spectral density functions are used to estimate the time-dependent power spectral density, and analysis of variance procedures are applied to determine whether the first and second moments of the data series exhibit statistically significant changes over short intervals. It is found that while the assumption of WSS is met in 40%-70% of half-second intervals for a single element at the transmitter and receiver, only 2%-12% of intervals with two elements at the transmitter and receiver are jointly WSS; furthermore, the occurrence of non-WSS intervals is not dependent on the antenna separation. The analyses also show that WSS intervals are interspersed with long non-WSS intervals.     

Link Performance of an ESPAR-Antenna Array in Rich Scattering and Clustered Channels

This paper aims at evaluating the link performance of an electronically steerable passive array radiator (ESPAR) in both rich scattering and clustered channels. Previous work has shown that the performance of an ESPAR-antenna can be comparable to a 2 × 2 multiple-input-multiple-output (MIMO) system in a rich scattering environment. The design of the antenna patterns used for transmission was based on intuition, and therefore cannot be guaranteed to be optimal. In this paper, we design the antenna patterns by minimizing the average inner-product between signals that are transmitted with different antenna patterns. We also evaluate the performance of the ESPAR-antenna at higher spectral-efficiencies than previous literature has done. The performance in terms of spectral-efficiency is evaluated for both rich scattering environments and clustered channels, whereas the performance in terms of symbol error rate is evaluated for rich scattering channels only.

Analysis of GMSK with Two-Bit Differential Detection in Land Mobile Radio Channels

The effect of intersymbol interference (ISI) of Gaussian filtered minimum shift keying (GMSK) on the probability of error of twobit differential detection is analyzed theoretically in fast Rayleigh fading characterizing land mobile radio channels. A closed form expression is derived for the probability of error. Numerical results are presented for cases of practical interest to researchers and designers of cellular land mobile radio systems.     

NR-DCSK Based Chaotic Communications in MIMO Multipath Channels

Wireless Personal Communications - In this paper, digital chaotic communications in multiple-input–multiple-output (MIMO) wireless multipath fading channels is considered. A noise...     

无线多径特性及其对陆地移动通信系统规划设计的影响

本文对无线多径传播特及其对陆地移动通信系统规划设计的影响、抗多径衰落措施等进行了论述.     

Performance of First-Order Digital Phase-Locked Loops in Mobile Radio Channels

The performance of a first-order digital phase-locked loop (DPLL) using nonuniform sampling is studied in the mobile radio environments. The mobile radio channel is characterized by introducing fast Rayleigh fading and random phase variation to the signal envelope and phase, respectively. The nonlinear stochastic difference equation describing the loop operation in fading environments is introduced. The joint probability density function (pdf) of the random variables of this equation is derived by transformation of random variables for fast Rayleigh fading channels. A closed-form expression for the transition probability of the ChapmanKolmogorov (C-K) equation is obtained for phase step plus noise input and for frequency step plus noise input. The probability density function of the steady-state phase error is obtained by solving the C-K equation numerically.     

910 MHz Urban Mobile Radio Propagation: Multipath Characteristics in New York City

Small scale statistics of multipath propagation in a heavily built-up urban mobile radio environment are presented. The statistics cover vehicle travel distances on the order of 30 m along streets. Measuring equipment time delay resolution is about 0.1 μs. In some locations, paths with significant amplitudes are observed with excess delays of 9 to 10 μs. The delay spreads (sqrt{second central moment of power delay profile}) in this environment are on the order of 2 μs. Often the signal at fixed delays has a Rayleighdistributed amplitude but large departures from the Rayleigh distribution also occur. From the measurements it appears reasonable to model the urban mobile radio channel as a Gaussian quasi-wide-sense stationary uncorrelated scattering channel within a bandwidth of 10 MHz and for intervals along the street of up to 30 m.     

Multipath Fading Effects on Digital Radio

An experimental study of multipath fading effects on an 8-PSK 6 GHz digital radio system was conducted on a 26.4 mi test link near Atlanta, Georgia. Results were obtained for a non-diversity arrangement and a space-diversity arrangement employing a cophasing combiner operating at 70 MHz and fed by two antennas separated by 30 ft. Multipath fading was found to have a significant impact on bit error rate performance, i.e., the digital radio system was fragile by comparison to conventional analog FM radio. Modest in-band linear amplitude dispersion, 0.2 dB/MHz for example, was sufficient to cause aBERgeq10^{-3}. Such dispersion occurred at (average power) fade depths as shallow as 20 dB. However, average fade depth was a poor indicator of BER performance. The measured hop missed short haul outage objectives by an order of magnitude without space-diversity, and was close to acceptable when diversity was activated.     

多径信道Turbo均衡技术性能分析

Turbo均衡技术将Turbo原理和均衡技术结合起来，通过对接收信号在均衡器和译码器之间迭代处理，提高系统抗符号间干扰（ISI）的能力。文中介绍了几种Turbo均衡技术，讨论了其计算复杂度，并给出了系统在Proakis信道下的误码性能。文中提出将应用于设计短波接收机。     

多径信道下辅助矢量接收机性能分析

研究了在直接序列码分多址(DS-CDMA)系统中,多径环境下一种基于RAKE结构的辅助矢量接收机。该接收机在收集多径信号的同时抑制系统中的多址干扰,从收集的多径信号中估计出信道响应矢量,并利用估计出的信道响应矢量对多径信号进行合并,最后进行判决。仿真结果表明,辅助矢量接收机能够有效地去除DS-CDMA系统中的多址干扰,同时具备良好的抗多径衰落性能,误码性能明显优于RAKE接收机。     

Statistical Approach for Performance Analysis of Multipath Scattering Environment

Wireless Personal Communications - In realistic scenarios, multipath scattering environments usually require an approach which can easily model signal behavior. We have considered a Rayleigh...     

Effects of Multipath Propagation on Digital Radio

This paper summarizes experimental work at Bell Laboratories in the field of multipath propagation as it affects digital radio. Field and laboratory measurements are presented on commercial-quality high-speed digital radio systems working in the 4, 6, and 11 GHz common carrier bands. Circuits and equipment used in these systems are all state of the art, but no attempt has been made to describe them in any detail. Modulation types are offset-4 PSK, conventional 8 PSK, and 16 QAM. Outages(BER > 10^{-3})vastly exceeding accepted objectives are measured on unprotected radio hops. A very effective method for reducing outages has been the use of a space diversity combiner followed by an amplitude slope equalizer. Results from single, as well as dual-polarized digital radio relay systems, are presented. The paper also describes the laboratory measurement of an equipment "signature" as a means to compare different digital radio designs in their sensitivity to multipath fading.     

Distributed Polar Coded Single Carrier-FDMA Based on Multilevel Construction Over Multipath Channels

Wireless Personal Communications - A multilevel constructed polar coded single carrier frequency division multiple access (MLPC-SCFDMA) scheme is proposed and its bit-error rate performance over...