In this paper, we study the performance of Space Shift Keying (SSK) modulation for a generic Multiple-Input-Multiple-Output (MIMO) wireless system over correlated Rician fading channels. In particular, our contribution is twofold, i) First, we propose a very general framework for computing the Average Bit Error Probability (ABEP) of SSK-MIMO systems over a generic Rician fading channel with arbitrary correlation and channel parameters. The framework relies upon the Moschopoulos method. We show that it is exact for MIMO systems with two transmit-antenna and arbitrary receive-antenna, while an asymptotically-tight upper-bound is proposed to handle the system setup with an arbitrary number of transmit-antenna. ii) Second, moving from the consideration that conventional SSK-MIMO schemes can offer only receive-diversity gains, we propose a novel SSK-MIMO scheme that can exploit the transmit-antenna to increase the diversity order. The new method has its basic foundation on the transmission of signals with good time-correlation properties, and is called Time-Orthogonal-Signal-Design (TOSD-) assisted SSK modulation (TOSD-SSK). It is shown that the proposed method can increase twofold the diversity order for arbitrary transmit- and receive-antenna. In particular, for MIMO systems with two transmit-antenna and Nr receive-antenna full-diversity equal to 2Nr can be achieved. Analytical frameworks and theoretical findings are substantiated via Monte Carlo simulations for various system setups.

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Space Shift Keying (SSK—) MIMO over Correlated Rician Fading Channels: Performance Analysis And a New Method for Transmit-Diversity

In this paper, we present a method to obtain a set of orthogonal pulses to be used in pulse-shape modulation (PSM) for ultra-wideband communications. The pulses are built as linear combinations of Hermite functions, which are shown to have unique advantageous features. Mathematical restrictions of orthogonality and spectral efficiency are introduced as guidelines to a fully explained search procedure to find the best set of pulses. Additionally, this procedure is adapted and used to find a single FCC-compliant pulse shape. A quaternary PSM scheme is implemented with orthogonal pulses obtained by the proposed method, and the results of a simulation are shown

Spectrally Efficient UWB Pulse Shaping With Application in Orthogonal PSM

This paper presents an updated survey on research related to ultra wideband (UWB) communications, particularly that of impulse radio (IR) technology. In addition to the research, we survey UWB physical layer specifications of the two existing standards-the IEEE 802.15.6-2012 and the IEEE 802.15.4-2015-as well as the leading global UWB spectrum regulatory limitations which have been updated recently. The latter standard including the UWB specifications was first published in 2007 and the latest revision dates to 2015. The focus in this paper is the period from 2007 to 2015. Our purpose is to provide an in-depth survey with a clearly specified topic together with the standard specifications and the related regulatory restrictions. Additionally, the last part of this paper discusses the possibilities of increasing the current IR-UWB data rates to meet increasing future demands.

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An Ultra Wideband Survey: Global Regulations and Impulse Radio Research Based on Standards

M-ary pulse shape modulation (PSM) has been proposed for achieving a high data rate even in severe multipath fading environments, based on the orthogonality of pulse waveforms of prolate spheroidal wave functions (PSWF). With respect to the PSWF-based M-ary PSM proposal, adaptive guard-time and selective-Rake receivers with different combining fingers are also considered The BER performance of the M-ary PSM, the guard-time and the Rake combination are investigated according to Monte-Carlo simulations by using the modified IEEE 802.15.3a S-V UWB multipath channel model. The proposed guard-time scheme has been verified to be effective in overcoming the inter-pulse-interferences. Moreover, it has been found that the PSWF-based pulse waveforms behave better than the conventional Gaussian mono-pulse under multipath fading conditions.

M-ary pulse shape modulation for PSWF-based UWB systems in multipath fading environment

Recent advances in electro-optical systems make them ideal for undersampling multiband signals with very high carrier frequencies. In this paper, we propose a new scheme for sampling and reconstructing of a multiband sparse signals that occupy a small part of a given broad frequency range under the constraint of a small number of sampling channels. The locations of the signal bands are not known a priori. The scheme, which we call synchronous multirate sampling (SMRS), entails gathering samples synchronously at few different rates whose sum is significantly lower than the Nyquist sampling rate. The signals are reconstructed by finding a solution of an underdetermined system of linear equations by applying a pursuit algorithm and assuming that the solution is composed of a minimum number of bands. The empirical reconstruction success rate is higher than obtained using previously published multicoset scheme when the number of sampling channels is small and the conditions for a perfect reconstruction in the multicoset scheme are not fulfilled. The practical sampling system which is simulated in our work consists of three sampling channels. Our simulation results show that a very high empirical success rate is obtained when the total sampling rate is five times higher than the total signal support of a complex signal with four bands. By comparison, a multicoset sampling scheme obtains a very high empirical success rate with a total sampling rate which is three times higher than the total signal support. However, the multicoset scheme requires 14 channels.

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Multirate Synchronous Sampling of Sparse Multiband Signals

In this paper we present a novel method for high data rate transmissions in ultra-wideband (UWB) communications systems. This is achieved through the combination of conventional pulse position modulation and pulse shape modulation schemes. The result is a pulse shape and position modulation that allows transmission of more bits of information in the same amount of time and using the same number of pulses as the conventional schemes. A feature of the proposed system is that the allowable alphabet is limited so as to ensure equal power in transmission of all symbols. Symbol size can also be easily changed without significantly changing the hardware of the system. Theoretical error performance analysis of this system is also provided.

Combined Pulse Shape and Pulse Position Modulation for High Data Rate Transmissions in Ultra-Wideband Communications

Orthogonal pulse-shape modulation using Hermite pulses for ultra-wideband communications is reviewed. Closed-form expressions of cross-correlations among Hermite pulses and their corresponding transmit and receive waveforms are provided. These show that the pulses lose orthogonality at the receiver in the presence of differentiating antennas. Using these expressions, an algebraic model is established based on the projections of distorted receive waveforms onto the orthonormal basis given by the set of normalized orthogonal Hermite pulses. Using this new matrix model, a number of pulse-shape modulation schemes are analyzed and a novel orthogonal design is proposed. In the proposed orthogonal design, transmit waveforms are constructed as combinations of elementary Hermites with weighting coefficients derived by employing the Gram-Schmidt (QR.) factorization of the differentiating distortion model's matrix. The design ensures orthogonality of the vectors at the output of the receiver bank of correlators, without requiring compensation for the distortion introduced by the antennas. In addition, a new set of elementary Hermite Pulses is proposed which further enhances the performance of the new design while enabling a simplified hardware implementation.

On the design of orthogonal pulse-shape modulation for UWB systems using Hermite pulses

A novel method for high data rate transmission in ultra-wideband (UWB) communications systems is presented. This is achieved through the exploitation of the orthogonality of the modified Hermite polynomial function. By transmitting multiple pulses simultaneously and applying appropriate error correction, one is able to achieve reliable communications at higher data rates. By applying the error correction coding in a multilayered manner in both the time and shape domains, high data rate transmissions are achieved with good error performance characteristics. In addition, we also expand the pulse shape and pulse time modulation presented and show a new method for transmitting more bits using the same number of pulses.

High data rate transmissions using orthogonal modified Hermite pulses in UWB communications

Combined pulse position and pulse shape modulation in UWB systems has been proposed. This achieves high data rates using the same number of pulses as conventional UWB systems. Due to the non uniform distribution of the modulation constellation points and the fact that these points are not orthogonal, the performance of the system suffers. We propose some methods to compensate for this performance degradation. By altering the modulation alphabet so as to obtain orthogonal points, one can expect improved performance. In addition, by applying coded modulation techniques and error correcting codes, it is possible to improve the performance of such a system significantly. Two different kinds of coding, namely Reed Solomon and trellis coding, are considered.

http://ieeexplore.ieee.org/iel5/9232/29256/01320959.pdf

Orthogonalized and coded modulation for combined pulse position and pulse shape modulation

The design of a class of jitter-robust, Hermite polynomial-based, orthogonal pulses for ultra-wideband impulse radio (UWB-IR) communications systems is presented. A unified and exact closed-form expression of the auto- and cross-correlation functions of Hermite pulses is provided. Under the assumption that jitter values are sufficiently smaller than pulse widths, this formula is used to decompose jitter-shifted pulses over an orthonormal basis of the Hermite space. For any given jitter probability density function (pdf), the decomposition yields an equivalent distribution of N-by-N matrices which simplifies the convolutional jitter channel model onto a multiplicative matrix model. The design of jitter-robust orthogonal pulses is then transformed into a generalized eigendecomposition problem whose solution is obtained with a Jacobi-like simultaneous diagonalization algorithm applied over a subset of samples of the channel matrix distribution. Examples of the waveforms obtained with the proposed design and their improved auto- and cross-correlation functions are given. Simulation results are presented, which demonstrate the superior performance of a pulse-shape modulated (PSM-) UWB-IR system using the proposed pulses, over the same system using conventional orthogonal Hermite pulses, in jitter channels with additive white Gaussian noise (AWGN).

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Craig John Mitchell

Papers

Combined Pulse Shape and Pulse Position Modulation for High Data Rate Transmissions in Ultra-Wideband Communications

On the design of orthogonal pulse-shape modulation for UWB systems using Hermite pulses

High data rate transmissions using orthogonal modified Hermite pulses in UWB communications

Orthogonalized and coded modulation for combined pulse position and pulse shape modulation

Jitter-robust orthogonal Hermite pulses for ultra-wideband impulse radio communications