Ultra-Compact FPGA-Based Fading Channel Simulators

Accurate emulation of fading channels is crucial for the efficient design and accurate performance verification of wireless communication systems under various propagation scenarios. A wide range of ultra-compact fading channel simulator cores provided by Ukalta Engineering support accurate emulation of diverse radio channel propagation scenarios in a laboratory setting and provide channel models for the latest standards, including LTE, WiMax, 802.11n and W-CDMA.

Fading channels can be divided into two models: frequency-flat (narrow-band) fading channels and frequency-selective fading channels. In a frequency-flat fading channel, the coherence bandwidth of the channel is greater than the bandwidth of the signal. Therefore, all frequency components of the signal will experience the same magnitude of fading. In a frequency-selective (multipath) fading channel, the bandwidth of the signal is greater than the coherence bandwidth of the channel. Therefore, different frequency components of the signal experience independent fading. While low data rate application may operate over a frequency-flat channel, modern wireless communication systems that target high data-rate transmission experience wide-band multipath fading channels.

Ukalta provides a complete set of single and multiple-antenna fading channel emulator IP cores. Multiple-input multiple-output (MIMO) fading channels supports various spatial-correlation models such as the Kronecker model, Weichselberger model, virtual channel representation (VCR) model and full-correlation model. Both analytical and geometrical channel models can be simulated efficiently using Ukalta’s fading channel solutions.

SINGLE-ANTENNA FADING CHANNELS

Part Number	Description	View Product Datasheet
USCH-FF-JKS	Frequency-flat fading channel simulator with Jakes’ classical Doppler spectrum: Ukalta’s USCH-FF-JKS core implements a frequency-flat fading channel. This channel emulator supports the classical Jakes’ Doppler power spectrum.
USCH-FF-USD	Frequency-flat fading channel simulator with user-defined power spectral densities: Ukalta’s USCH-FF-USD core implements a frequency-flat fading channel. This channel emulator generates fading samples with any Doppler spectrum shape, including support for flat, Gaussian, rounded, bell and Jakes’ power spectral densities.
USCH-FS-JKS	Frequency-selective fading channel simulator with Jakes’ classical Doppler spectrum: Ukalta’s USCH-FS-JKS core implements a multipath fading channel. This channel emulator supports the classical Jakes’ Doppler power spectrum. The delay between independent paths can be set by the user.
USCH-FS-USD	Frequency-selective fading channel simulator with user-defined power spectral densities: Ukalta’s USCH-FS-USD core implements a multipath fading channel. This channel emulator generates fading samples with any Doppler spectrum shape, including support for flat, Gaussian, rounded, bell and Jakes’ power spectral densities. The delay between independent paths can be set by the user.
USCH-GEO	Geometric fading channel simulator: Geometric channel models characterize the fading channels based on the physical characteristics of wave propagation or actual measurements. A geometric fading channel model considers the relative location of transmitter, receiver, and scatterers in the radio propagation channel. Ukalta’s USCH-GEO geometric fading channel emulator IP core simulates single- and double-bounce geometric fading channels using one-ring, two-ring and elliptical scattering models.

MULTIPLE ANTENNA FADING CHANNELS

Part Number	Description	View Product Datasheet
UMCH-FF-JKS	Frequency-flat MIMO fading channel simulator with Jakes’ classical Doppler spectrum: Ukalta’s UMCH-FF-JKS core implements a frequency-flat MIMO fading channel. This channel emulator supports the classical Jakes’ Doppler power spectrum and various spatial correlation models.
UMCH-FF-USD	Frequency-flat MIMO fading channel simulator with user-defined power spectral densities: Ukalta’s UMCH-FF-USD core implements a frequency-flat fading channel. This channel emulator generates spatially-correlated fading samples with any Doppler spectrum shape, including support for flat, Gaussian, rounded, bell and Jakes’ power spectral densities.
UMCH-FS-JKS	Frequency-selective MIMO fading channel simulator with Jakes’ classical Doppler spectrum: Ukalta’s UMCH-FS-JKS core implements a multipath MIMO fading channel. This channel emulator supports the classical Jakes’ Doppler power spectrum and various spatial correlation models. The delay between independent paths can be set by the user.
UMCH-FS-USD	Frequency-selective MIMO fading channel simulator with user-defined power spectral densities, supporting the latest standards such as LTE, WiMax and 802.11n. Ukalta’s UMCH-FS-USD core implements a multipath MIMO fading channel. This channel emulator generates spatially-correlated fading samples with any Doppler spectrum shape, including support for flat, Gaussian, rounded, bell and Jakes’ power spectral densities. The delay between independent paths can be set by the user. The UMCH-FS-USD supports the latest wireless standards and is ready for future standards such as LTE-Advanced and WiMax 802.16m. Current standard channel model support includes fading profiles from LTE, WiMax (802.16-2009), W-CDMA/HSPA (UMTS), and WLAN/WiFi (802.11n).
UMCH-GEO	Geometric MIMO fading channel simulator: In contrast to analytical MIMO channel models, geometric channel models characterize the fading channels based on the physical characteristics of wave propagation or actual measurements. A geometric MIMO channel model considers the relative location of transmitter, receiver, and scatterers in the radio propagation channel. Ukalta’s UMCH-GEO geometric MIMO fading channel emulator IP core simulates single and double-bounce geometric fading channels using one-ring, two-ring and elliptical scattering models.

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Random Number Generators

Gaussian Noise Generator

Sequences of random variates with a Gaussian probability density function (PDF) are widely used to model noisy natural phenomena. Ukalta’s ultra-compact and accurate Gaussian noise generator IP cores allow designers to use the most-efficient Gaussian noise generators in the market. These IP cores are ideal as a source of additive white-Gaussian noise (AWGN) in communication system testing.

GAUSSIAN NOISE GENERATOR

Part Number	Description	View Product Datasheet
UGNG-31	Gaussian noise generator with 1% accuracy up to ±3.1σ of the standard normal distribution: Ukalta’s UGNG-31 IP core provides an ultra-compact and high-throughput Gaussian noise generator with 1% accuracy up to ±3.1σ of the standard normal distribution.
UGNG-57	Gaussian noise generator with 0.2% accuracy up to ±5.7σ of the standard normal distribution: Ukalta’s UGNG-57 IP core provides an ultra-compact and high-throughput Gaussian noise generator with 0.2% accuracy up to ±5.7σ of the standard normal distribution.
UGNG-71	Gaussian noise generator with 0.2% accuracy up to ±7.1σ of the standard normal distribution: Ukalta’s UGNG-71 IP core provides an ultra-compact and high-throughput Gaussian noise generator with 0.2% accuracy up to ±7.1σ of the standard normal distribution.

Statistically-Accurate Uniform Random Number Generators with Extremely Long Periods

Most commonly-used pseudo-random number generators (PRNGs) are based on linear recurrence. These deterministic PRNGs, including the well-known linear feedback shift registers and cellular automata, have fast and compact implementations, and can ensure very long periods. However, the states generated by linear PRNGs in fact have a very regular structure and are thus not suitable for applications that rely on the assumption of uniformly distributed pseudo-random numbers. Ukalta’s UPRNG package provides a library of PRNG IP cores with extremely long periods and excellent equidistribution properties. These IP cores are based on algorithms such as TT800, Mersenne Twister (MT), SIMD-oriented fast Mersenne Twister (SFMT), and Well Equidistributed Long-period Linear (WELL).

STATISTICALLY-ACCURATE UNIFORM PRNG LIBRARY

Part Number	Description	View Product Datasheet
UPRNG	A library of pseudo-random uniform number generators: Ukalta’s UPRNG package provides a library of pseudo-random uniform number generator IP cores with excellent statistical properties and extremely long periods.