Indranil Sen

Vehicle–Vehicle Channel Models for the 5-GHz Band

In this paper, we describe the results of a channel measurement and modeling campaign for the vehicle-to-vehicle (V2V) channel in the 5-GHz band. We describe measurements and results for delay spread, amplitude statistics, and correlations for multiple V2V environments. We also discuss considerations used in developing statistical channel models for these environments and provide some sample results. Several statistical channel models are presented, and using simulation results, we elucidate tradeoffs between model implementation complexity and fidelity. The channel models presented should be useful for system designers in future V2V communication systems.

5 GHZ wireless channel characterization for vehicle to vehicle communications

We provide channel modeling results based upon measurements of the vehicle-to-vehicle (VTV) mobile channel, taken in the 5 GHz frequency band. Our measurements pertain to three types of areas: large cities, open highway areas, and small cities. A spread-spectrum stepped correlator technique was used, with omnidirectional antennas either atop or inside the vehicles. We provide measured and analytical results in the form of power delay profiles and frequency correlation function estimates. Delay spread statistics for these environments, as well as approximate amplitude fading distributions are also provided. The largest values of root-mean-square delay spreads, on the order of 1 microsecond, were obtained in urban areas with dense vehicle traffic, corresponding to coherence bandwidths of as low as 1-2 MHz. Fading amplitude statistics are best fit with a Nakagami-m distribution. Fading channel statistics for an example 10 MHz channel bandwidth are also provided.

5-GHz-Band Vehicle-to-Vehicle Channels: Models for Multiple Values of Channel Bandwidth

In Sen and Matolaks earlier paper, 5-GHz-band vehicle-to-vehicle (V2V) channel models were presented for channel bandwidths of 5 and 10 MHz. In this paper, we provide additional tapped delay line models for bandwidths of 1, 20, 33.33, and 50 MHz based upon the data used in Sen and Matolaks paper. We provide tables of channel parameters for five types of V2V channel classes and also include example tap correlation coefficients. Root-mean-square delay spread values are summarized, as are values of bandwidth for which the channel frequency correlation takes values of 0.7 and 0.5. As with the results from Sen and Matolaks paper, these models should be useful for designers in future V2V communication systems.

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

This paper describes results from a channel measurement campaign performed at several small airports in the U.S. in the 5-GHz band. This paper is a companion to another paper, which describes channel models for large airports. We classify the small airport surface channel into three propagation regions based upon different delay dispersion conditions. The channel characteristics of these regions in the delay and frequency domains are discussed with examples. We provide empirical stochastic channel models (of different bandwidths) to accurately represent the channel on the airport surface area for all propagation regions. The models are provided in the form of tapped delay lines, and complete statistical tap descriptions are given. Several key observations, including the presence of severe amplitude fading, some correlated scattering, and statistically nonstationary behavior, are also discussed.

Channel Modeling for V2V Communications

In this paper we describe results of a channel measurement campaign for modeling the V2V channel. After review of applications, potential frequency bands, and related work, we describe the measurements and results for delay spreads and multipath component fading amplitudes and correlations, made in multiple V2V environments. We also note how the V2V channel can differ appreciably from other common terrestrial (e.g., cellular) channels. We describe considerations used in developing the statistical channel models for these environments, and provide some example measurement and modeling results that should be useful for system designers in future V2V applications

Performance Evaluation of 802.16e in Vehicle to Vehicle Channels

Vehicle to vehicle (V2V) communications have drawn much attention in the past few years. The IEEE 802.16e standard systems can be considered potential candidates for these applications due to their attractive features, like high data rate, mobility support, etc. In this paper, we evaluate the performance of an 802.16e system with the OFDMA air interface in two non-stationary vehicle to vehicle (V2V) channels: an open area high traffic density (OHT) channel and an urban (UOC) channel. We first introduce the non-stationary V2V channel models developed from empirical data. Then we provide a brief overview of 802.16e and introduce three channel estimation schemes that apply to different scenarios. Finally, we evaluate the performance of the 802.16e system over the proposed non-stationary V2V channel models. We show that the proposed channel estimation methods provide a good tradeoff between channel estimation accuracy and computational complexity. We also illustrate that system performance in non-stationary channels is more volatile than in stationary channels.

Generation of multivariate Weibull random variates

A simple and efficient method for generating correlated multivariate Weibull random variables with arbitrary fading parameters and arbitrary average powers is proposed. The multivariate Weibull random variables generated via this method can be used to simulate the performance of wireless communication systems with any diversity order or channel impulse response length, under arbitrary correlated Weibull fading conditions.

V2V Channels and Performance of Multi-User Spread Spectrum Modulation

Vehicle to vehicle (V2V) communications have drawn much attention in recent years. In this paper, we discuss tradeoffs between implementation complexity and accuracy of several stochastic channel models for the V2V environment, and then address spread spectrum system performance attained using these channel models. Two different propagation environments are considered: urban and open areas (highways). The necessity of employing non-stationary channel models to accurately represent the channel is substantiated by comparing stationary and non-stationary empirical model outputs with measured data. A framework to compare single carrier direct sequence code division multiple access (SC-DS-CDMA) and multicarrier DS-CDMA (MC-DS-CDMA) performance in V2V channels is presented, and bit error ratio (BER) performance of the schemes is provided for the two channels. Our comparison of single- and multi-user performance shows that MC-DS-CDMA performs better than SC-DS-CDMA in both V2V environments.

V2V channels and performance of multiuser spread spectrum modulation

Vehicle-to-vehicle (V2V) communications have drawn much attention in recent years. In this article, we discuss tradeoffs between implementation complexity and accuracy of several stochastic channel models for lite V2V environment, and then address spread-spectrum system performance attained using these channel models. Two different propagation environments are considered: urban and open areas (highways). The necessity of employing nonstationary channel models to accurately represent the channel is substantiated by comparing stationary and nonstationary empirical model outputs with measured data. A framework to compare single-carrier direct sequence code division multiple access (SC-DS-CDMA) and mul- ticarrier DS-CDMA (MC-DS-CDMA) performance in V2V channels is presented, and bit error ratio (BER) performance of the schemes is provided for the two channels Our comparison of single- and multiuser performance shows that MC-DS-CDMA performs better than SC-DS-CDMA in both Y2V environments.

Channel Measurement/Modeling for Airport Surface Communications: Mobile and Fixed Platform Results

We provide examples of measurement and modeling results for wireless channel characteristics around airport surface areas. This is done for three settings: two mobile settings and one non-mobile setting, in the 5 GHz Microwave Landing System extension band. New findings, useful for communication system design in this environment, are reported.