In this paper, we study network-coded cooperative diversity (NCCD) systems comprising multiple sources, one relay, and one destination, where the relay detects the packets received from all sources and performs Galois field (GF) network coding over rm GF(2m) before forwarding a single packet to the destination. Assuming independent Rayleigh fading for all links of the network, we derive simple and accurate closed-form approximations for the asymptotic symbol and bit error rates of NCCD systems. The derived error rate expressions are valid for arbitrary numbers of sources, arbitrary modulation schemes, and arbitrary constellation mappings and provide significant insight into the impact of various system and channel parameters on performance. Moreover, these expressions can be exploited for optimization of the constellation mapping as well as for formulation of various NCCD system optimization problems including optimal power allocation, relay selection, and relay placement.

In this paper, we provide a high signal-to-noise ratio (SNR) error rate analysis of amplify-and-forward (AF) best relay selection in networks impaired by Rayleigh fading and generic, possibly non-Gaussian noise. The derived closed - form asymptotic error rate expressions are applicable to any type of noise with finite moments. Exploiting these analytical results, we formulate a power allocation problem with energy consumption fairness constraints for the source and the relays, which is solved using monomial fitting and a series of geometric programs. The accuracy of the derived analytical results and the effectiveness of the proposed power allocation scheme are confirmed with computer simulations.

In this letter, we investigate the performance of generalized selection combining in channels impaired by generalized fading and generic noise with finite moments. In particular, we derive accurate high signal-to-noise ratio approximations for the bit and symbol error rates of linear modulation schemes, which offer significant insight into the impact of the number of selected diversity branches, the type of fading, and the type of noise. Our analysis is applicable to all practically relevant types of fading including Rayleigh, Rician, Nakagami-q, and Nakagami-m fading, all types of noise with finite moments including Gaussian noise, Gaussian mixture noise, generalized Gaussian noise, and co-channel interference, and non-identically distributed fading and noise across the diversity branches. Our results reveal that while performance always improves with increasing number of selected branches for identically distributed noise, this is not necessarily true for non-identically distributed noise.

Best relay selection (BRS) has received considerable attention in the literature as it makes efficient use of the system resources and achieves full diversity. Partial relay selection (PRS) is an alternative to BRS and performs relay selection based on local channel state information (CSI) only at the expense of a loss in diversity. Although, in practice, relays may be deployed in unfavorable environments exposing them to non-Gaussian impairments, existing analyses and design guidelines for BRS and PRS are limited to additive white Gaussian noise channels. In this paper, we analyze the error rate of BRS and PRS in the asymptotic regime of high signal-to-noise ratio (SNR) for amplify-and-forward (AF) relays and impairment by generic noise and interference. The derived analytical results are valid for Gaussian and non-Gaussian noises with finite moments, independent and non-identically distributed Rayleigh fading, and arbitrary linear modulation schemes. In order to reduce the signaling overhead required for CSI acquisition, we propose a relay subset selection scheme for BRS and PRS. Furthermore, to guarantee fairness in energy resource usage across the relays, we introduce a fair and flexible power allocation scheme with energy consumption constraints which does not affect the achievable diversity gain. The proposed relay subset selection and power allocation schemes only require knowledge of the average CSI of the links and certain moments of the noises impairing the relays and the destination.

In this paper, we study a cooperative diversity scheme for wireless systems employing network coding and the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The considered system comprises multiple sources, one relay, and one destination. The relay decodes the signal received from all sources and performs network coding before forwarding the signal to the destination. We propose a simple cooperative maximum-ratio combining scheme for the destination which can successfully exploit the full spatial and frequency diversity offered by the channel for arbitrary numbers of sources and arbitrary linear modulation schemes. Furthermore, we propose techniques to reduce the signaling overhead and the decoding complexity at the destination. To gain insight for system design, we derive a closed-form upper bound for the asymptotic worst-case pairwise error probability and the diversity gain of the considered network coded cooperative BICM-OFDM system. These analytical results reveal the influence of various system parameters, including the number of sources, the free distance of the code, and the frequency diversity of the involved links, on performance. Based on the derived analytical results, we develop schemes for optimal relay placement and power allocation. Simulation results corroborate the derived analytical results and confirm the effectiveness of the developed optimization framework.

In this letter, we propose a novel enhanced maximal-ratio combining (E-MRC) scheme for multi-branch decode-and-forward (DF) cooperative diversity systems consisting of a source, a destination, and multiple relays. This scheme employs adjustable parameters at the relays and the destination which enable this scheme to appropriately adapt to variations in the source-relay and relay-destination channel gains. For the proposed E-MRC scheme, we analyze the asymptotic error rate performance for high signal-to-noise ratios and Rayleigh fading. Based on the obtained analytical expressions, we find the optimal parameters that lead to minimization of the asymptotic error rate. Furthermore, we compare the error rate performance as well as the feedback overhead of E-MRC with those of important DF schemes, namely, cooperative MRC (C-MRC) and two DF schemes based on the link adaptive regeneration (LAR) concept, namely, LAR-αinstand LAR-α. We show that although the feedback requirements of E-MRC are similar to those of LAR-α, E-MRC achieves a performance similar to that of LAR-αinst, which has a substantially higher feedback overhead.

In this paper, we study a cooperative diversity scheme for wireless systems employing network coding and the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The considered system comprises multiple sources, one relay, and one destination. The relay decodes the signal received from all sources and performs network coding before forwarding the signal to the destination. We propose a simple cooperative maximum-ratio combining scheme for decoding at the destination which can successfully exploit the full spatial and frequency diversity offered by the channel for arbitrary number of sources and arbitrary modulation schemes. We derive a closed-form upper bound for the asymptotic worst-case pairwise error probability and the diversity gain of the considered network coded cooperative BICM-OFDM scheme. Simulation results corroborate the derived diversity gain and show the effectiveness of a low complexity decoding scheme.

In this paper, we study a decode-and-forward cooperative diversity scheme for wireless systems using the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). We propose a simple cooperative maximum-ratio combining scheme for the destination which can successfully exploit the full spatial and frequency diversity offered by the channel. Taking possible decision errors at the relay into account, we develop a closed- form upper bound on the asymptotic worst-case pairwise error probability (PEP) of the considered cooperative diversity system which provides insight into the influence of various code and channel parameters on performance. The PEP expression is then exploited for optimal relay placement. Simulation results corroborate the derived analytical results regarding the diversity gain of the system and confirm the effectiveness of the proposed relay placement scheme.

In cognitive radio (CR) systems, reliable spectrum sensing techniques are required in order to avoid interference to the primary users of the spectrum. Whereas most of the existing literature on spectrum sensing considers impairment by additive white Gaussian noise (AWGN) only, in practice, CRs also have to cope with various types of non-Gaussian noise such as man-made impulsive noise, co-channel interference, and ultra-wideband interference. In this paper, we propose an adaptive Lp-norm detector which does not require any a priori knowledge about the primary user signal and performs well for a wide range of circularly symmetric non-Gaussian noises with finite moments. We analyze the probabilities of false alarm and missed detection of the proposed detector in Rayleigh fading in the low signal-to-noise ratio regime and investigate its asymptotic performance if the number of samples available for spectrum sensing is large. Furthermore, we consider the deflection coefficient for optimization of the Lp-norm parameters and discuss its connection to the probabilities of false alarm and missed detection. Based on the deflection coefficient an adaptive algorithm for online optimization of the Lp-norm parameters is developed. Analytical and simulation results show that the proposed Lp-norm detector yields significant performance gains compared to conventional energy detection in non-Gaussian noise and approaches the performance of the locally optimal detector which requires knowledge of the noise distribution.

Cooperative diversity systems have received significant attention recently as a distributed means of exploiting the inherent spatial diversity of wireless networks. In this paper, we consider a cooperative diversity system consisting of a source, a destination, and multiple single-hop amplify-and-forward relays, and provide a mathematical framework for the asymptotic analysis of this system in generic noise and interference for high signal-to-noise ratios. Assuming independent Rayleigh fading for all links in the network and orthogonal relay-destination channels, we obtain simple and elegant closed-form expressions for the asymptotic symbol and bit error rates valid for arbitrary linear modulation formats, arbitrary numbers of relays, and arbitrary types of noise and interference with finite moments including co-channel interference, ultra-wideband interference, impulsive ε-mixture noise, generalized Gaussian noise, and Gaussian noise. Furthermore, we exploit the derived analytical error rate expressions to develop power allocation, relay selection, and relay placement schemes that are asymptotically optimal in environments with generic noise and interference. In general, the power allocation problem results in a geometric program which can be solved efficiently numerically. For the special case of only one relay, we provide a closed-form result for the optimal power allocation. Simulation results confirm our analysis and illustrate that, in non-Gaussian noise, the proposed power allocation, relay selection, and relay placement schemes lead to large performance gains compared to their conventional counterparts optimized for Gaussian noise.

The keyhole phenomenon, i.e., non-fully correlated but rank-deficient fading, can lead to significant performance degradations in multiple-input multiple-output (MIMO) systems and has to be carefully taken into account for system design. In this paper, we consider generalized keyhole fading including Rayleigh, Ricean, Nakagami-q, Nakagami-m, and Weibull fading. We derive simple and elegant closed-form expressions for the asymptotic pairwise error probability (PEP) of both single-antenna transmission and space-time coded transmission with two transmit antennas. The obtained PEP expressions provide significant insight into the impact of various system and channel parameters such as the types of fading at the transmitter and receiver side, the numbers of transmit and receive antennas, and the space-time code design on performance. This insight can be exploited for system design and to explain the differences in the performance of space-time codes in non-keyhole and keyhole fading channels. Furthermore, the presented asymptotic PEP expressions can be utilized to obtain tight asymptotic approximations for the bit, symbol, and frame error probabilities of arbitrary, not necessarily orthogonal, space-time codes. Simulation results confirm the accuracy and usefulness of the derived results.

In this paper, we study network-coded cooperative diversity (NCCD) systems comprising multiple sources, one relay, and one destination. The relay detects the packets received from all sources and performs Galois field network coding. We propose a simple cooperative maximum-ratio combining scheme for the destination which is shown to achieve the maximum diversity gain of the system. Furthermore, we provide a mathematical framework for the asymptotic analysis of NCCD systems with M-ary modulation for high signal-to-noise ratios. Based on this framework, we derive simple and elegant closed- form expressions for the asymptotic symbol and bit error rates which provide significant insight into the impact of various system and channel parameters on performance and can be exploited for performance optimization. Simulation results confirm the accuracy of the presented analysis and show that large performance gains are possible by optimizing the power allocation in NCCD systems based on the developed analytical results.

Cooperative diversity (CD) systems have received significant attention recently as a distributed means of exploiting the inherent spatial diversity of wireless networks. In this paper, we consider a CD system where a source transmits to a destination via multiple single--hop amplify and forward (AF) relays. In particular, we provide a mathematical framework for the asymptotic analysis of this system in general non--Gaussian noise and interference for high signal--to--noise ratios (SNRs). Assuming independent Rayleigh fading for all links in the network, we obtain simple and elegant closed--form expressions for the asymptotic symbol error rate (SER) and bit error rate (BER) valid for arbitrary linear modulation formats, arbitrary numbers of relays, and arbitrary non--Gaussian noise and interference with finite moments. Furthermore, exploiting the derived analytical results, we introduce a new relay selection criterion for non--Gaussian environments. Simulation results confirm our analysis and illustrate that, in non--Gaussian noise, the proposed relay selection criterion can lead to large performance gains compared to the conventional relay selection criterion which was optimized for Gaussian noise.

The keyhole phenomenon, i.e., uncorrelated but rank-deficient fading, can lead to significant performance degradations in multiple-input multiple-output (MIMO) systems and has to be carefully taken into account for system design. In this paper, considering the practically important case of two transmit and an arbitrary number of receive antennas, we provide a simple closed-form expression for the asymptotic pairwise error probability (PEP) of space-time codes (STCs) in generalized keyhole fading channels including Rayleigh, Ricean, Nakagami-q, Nakagami-m, and Weibull fading. We show how the number of transmit and receive antennas as well as the fading parameters affect the diversity gain. The presented analysis provides new insights into STC design and can be used to obtain tight asymptotic upper bounds for the bit, symbol, and frame error probabilities of arbitrary STCs in keyhole fading.

The frequency bands used by secondary user systems such as cognitive radio and ultra-wideband (UWB) systems are subject to various forms of non-Gaussian noise and interference including co-channel and narrowband interference caused by the primary user and other secondary users as well as man-made impulsive noise. For secondary user systems employing popular bit-interleaved coded modulation (BICM) we propose a robust Lp-norm metric for Viterbi decoding to overcome the harmful effects of non-Gaussian noise and interference. For the resulting system, we derive an approximate upper bound on the bit error rate (BER) and a general analytical expression for the asymptotic BER valid for all practically relevant types of fading, including Rayleigh, Ricean, Nakagami-m, Nakagami-q, and Weibull fading, and all types of noise and interference with finite moments. Simulation and analytical results show that, in non-Gaussian noise and interference, the proposed Lp-norm metric yields large performance gains over the conventional L2-norm metric and outperforms erasure decoding.

In cognitive radio (CR) systems reliable spectrum sensing techniques are required in order to avoid interference to the primary users of the spectrum. Whereas most of the existing literature on spectrum sensing considers impairment by additive white Gaussian noise (AWGN) only, in practice, CRs also have to cope with various types of non-Gaussian noise such as man-made impulsive noise, co-channel interference, and ultrawideband interference. In this paper, we propose robust Lp-norm detectors which do not require any a priori knowledge about the primary user signal and perform well for a wide range of nonGaussian noises. Furthermore, we analyze the probabilities of false alarm and missed detection of the proposed detectors in the low signal-to-noise ratio regime. For optimization of Lp-norm detection we propose a direct approach based on minimization of the probability of false alarm for a given probability of missed detection and a simpler approach based on maximization of the deflection coefficient of the detector. Analytical and simulation results show that the proposed Lp-norm detectors achieve significant performance gains over conventional energy detection in non-Gaussian noise.

The frequency bands used by secondary systems such as cognitive radio (CR) and ultra-wideband (UWB) systems are subject to various forms of non-Gaussian noise and interference including co-channel interference caused by the primary user and other secondary systems and man-made impulsive noise. For secondary systems employing the popular combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM) it has been recently shown that robustness against the negative effects of non-Gaussian impairments can be achieved by replacing the conventional L2-norm metric for Viterbi decoding with an Lp- norm metric. However, in order to achieve high performance, the metric parameter p has to be optimized for the underlying type of noise. In this paper, we propose two adaptive algorithms for online optimization of p. The first algorithm is based on a maximum-likelihood parameter estimation framework. The second algorithm is based on the direct minimization of the asymptotic bit error rate of Lp-norm decoding. Simulation results show that both algorithms have excellent performance and that the resulting adaptive Lp-norm metric outperforms other popular metrics in non-Gaussian noise channels.

In this paper, we introduce an adaptive Lp-norm metric for robust coherent diversity combining in non-Gaussian noise and interference. We derive a general closed-form expression for the asymptotic bit error rate (BER) for Lp-norm combining in independent non-identically distributed Ricean fading and non-Gaussian noise and interference with finite moments. Based on this asymptotic BER expression, the metric parameters can be adapted to the underlying type of noise and interference using a finite difference stochastic approximation (FDSA) algorithm. Simulation results confirm the validity of the derived asymptotic BER expression and the excellent performance of the proposed adaptive Lp-norm metric.

In this paper, we present a general mathematical framework for performance analysis of single-carrier (SC) and orthogonal frequency division multiplexing (OFDM) systems employing popular bit-interleaved coded modulation (BICM) and multiple receive antennas. The proposed analysis is applicable to BICM systems impaired by general types of fading (including Rayleigh, Ricean, Nakagami-m, Nakagami-q, and Weibull fading) and general types of noise and interference with finite moments such as additive white Gaussian noise (AWGN), additive correlated Gaussian noise, Gaussian mixture noise, co-channel interference, narrowband interference, and ultra-wideband interference. We present an approximate upper bound for the bit error rate (BER) and an accurate closed-form approximation for the asymptotic BER at high signal-to-noise ratios for Viterbi decoding with the standard Euclidean distance branch metric. For the standard rate-1/2 convolutional code the proposed approximate upper bound and the asymptotic approximation become tight at BERs of 10-6and 10-12, respectively. However, if the code is punctured to higher rates (e.g. 2/3 or 3/4), the asymptotic approximation also becomes tight at a BER of 10-6. Exploiting the asymptotic BER approximation we show that the diversity gain of BICM systems only depends on the free distance of the code, the type of fading, and the number of receive antennas but not on the type of noise. In contrast their coding gain strongly depends on the noise moments. Our asymptotic analysis shows that as long as the standard Euclidean distance branch metric is used for Viterbi decoding, BICM systems optimized for AWGN are also optimum for any other type of noise and interference with finite moments.

In this paper, we study the asymptotic behavior of the bit-error probability (BEP) and the symbol-error probability (SEP) of quadratic diversity combining schemes such as coherent maximum-ratio combining (MRC), differential equal-gain combining (EGC), and noncoherent combining (NC) in correlated Ricean fading and non-Gaussian noise, which in our definition also includes interference. We provide simple and easy-to-evaluate asymptotic BEP and SEP expressions which show that at high signal-to-noise ratios (SNRs) the performance of the considered combining schemes depends on certain moments of the noise and interference impairing the transmission. We derive general rules for calculation of these moments and we provide closed-form expressions for the moments of several practically important types of noise such as spatially dependent and spatially independent Gaussian mixture noise, correlated synchronous and asynchronous co-channel interference, and correlated Gaussian interference. From our asymptotic results we conclude that (a) the asymptotic performance loss of binary frequency-shift keying (BFSK) with NC compared to binary phase-shift keying (BPSK) with MRC is always 6 dB independent of the type of noise and the number of diversity branches, (b) the asymptotic performance loss of differential EGC compared to MRC is always 3 dB for additive white Gaussian noise but depends on the number of diversity branches and may be larger or smaller than 3 dB for other types of noise, and (c) not only fading correlation but also noise correlation negatively affects the performance of quadratic diversity combiners.

In this paper, we introduce an adaptive Lp-norm metric for robust coherent, differential, and noncoherent diversity combining in non-Gaussian noise and interference. We consider the general case where all diversity branches may use different combining weights and different Lp-norms. We derive a general closed-form expression for the asymptotic bit error rate (BER) for Lp-norm combining in independent non-identically distributed Ricean fading and non-Gaussian noise and interference with finite moments. The asymptotic BER expression reveals that the diversity gain of Lp-norm combining is independent of the type of noise and the metric parameters. In contrast, the combining gain depends on both the type of noise and the metric parameters. Thus, the asymptotic BER can be minimized by optimizing the Lp-norm metric parameters for the underlying type of noise. For this purpose finite difference stochastic approximation (FDSA) and localized random search (LRS) algorithms are developed. Both adaptive algorithms do not require any a priori knowledge about the underlying noise and are able to track changes in the noise statistics. Simulation results confirm the validity of the derived asymptotic BER expressions, the effectiveness of the proposed adaptive algorithms, and the excellent performance of the proposed adaptive Lp-norm metric compared to other popular metrics.

In this paper, we develop an analytical framework for performance analysis of generic bit-interleaved coded modulation orthogonal frequency-division multiplexing (BICMOFDM) systems impaired by ultra-wideband (UWB) interference. For practical relevance we consider multi-band OFDM (MB-OFDM), direct-sequence UWB (DS-UWB), and impulseradio UWB (IR-UWB) interference formats following recent IEEE/ECMA standards or standard proposals. Besides the exact analysis we calculate the bit error rate (BER) for the case when the UWB interference is modeled as additional Gaussian noise. Our results show that in general the BER of the BICM-OFDM system strongly depends on the UWB format and the OFDM sub-carrier spacing. While the Gaussian approximation is very accurate for DS-UWB, it may severely overor underestimate the true BER for MB-OFDM and IR-UWB interference. Our analysis is applicable to e.g. IEEE 802.11 wireless local area networks (WLANs), IEEE 802.16 wireless access systems (WiMAX), and 4th generation mobile communication systems. Furthermore, since the ECMA MB-OFDM standard is also based on the BICM-OFDM concept, our analysis can also be used to evaluate the impact of other UWB signals on ECMA MB-OFDM UWB systems.

In this paper, we present a general mathematical framework for performance analysis of systems employing bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed analysis is general enough to include impairment by general types of noise and interference with finite moments such as additive white Gaussian noise (AWGN), Gaussian mixture noise, narrowband interference, and ultra-wideband interference. We present an asymptotically tight upper bound for the bit error rate (BER) and a closed-form expression for the asymptotic BER at high signal-to-noise ratios. Our analysis shows that, if the popular Euclidean distance metric is used for Viterbi decoding, BICM-OFDM systems optimized for AWGN are also optimum for any other type of noise and interference with finite moments.

In this paper, we propose a theoretical framework for the analysis of the impact of ultra-wideband (UWB) interference on systems that use the popular combination of bit- interleaved coded modulation (BICM) and orthogonal frequency- division multiplexing (OFDM). For the UWB interference we consider multi-band OFDM (MB-OFDM), direct-sequence UWB (DS-UWB), and impulse-radio UWB (IR-UWB) formats following recent IEEE/ECMA standards and standard proposals. Our analysis is applicable to generic BICM-OFDM victim systems including IEEE 802.11 wireless local area networks (WLANs), IEEE 802.16 wireless access systems (WiMAX), and 4th generation mobile communication systems. Besides the exact analysis we also calculate the bit-error rate for the case when the UWB interference is modeled as additional Gaussian noise. Our results show that in general the BER of the BICM-OFDM system strongly depends on the type of the UWB interference and the sub-carrier spacing. While the Gaussian approximation is very accurate for DS-UWB, it may severely over- or underestimate the true BER for MB-OFDM and IR-UWB interference.

In this paper, we present a unified asymptotic symbol error rate (SER) analysis of linearly modulated signals impaired by fading and (possibly) non-Gaussian noise, which in our definition also includes interference. The derived asymptotic closed-form results are valid for a large class of fading and noise processes. Our analysis also encompasses diversity reception with equal gain and selection combining and is extended to binary orthogonal modulation. We show that for high signal-to-noise ratios (SNRs) the SER of linearly modulated signals depends on the Mellin transform of the probability density function (pdf) of the noise. Since the Mellin transform can be readily obtained for all commonly encountered noise pdfs, the provided SER expressions are easy and fast to evaluate. Furthermore, we show that the diversity gain only depends on the fading statistic and the number of diversity branches, whereas the combining gain depends on the modulation format, the type of fading, the number of diversity branches, and the type of noise. An exception are systems with a diversity gain of one, since their combining gain and asymptotic SER are independent of the type of noise. However, in general, in a log-log scale for high SNR the SER curves for different types of noise are parallel but not identical and their relative shift depends on the Mellin transforms of the noise pdfs.

In this paper, we study the asymptotic behavior of the bit-error probability (BEP) and symbol-error probability (SEP) of differential M-ary phase-shift keying with differential equal gain combining (DEGC) in correlated Ricean fading and non-Gaussian noise, which in our definition also includes interference. We derive simple and easy-to-evaluate asymptotic BEP and SEP expressions which show that at high signal- to-noise ratios (SNRs) the performance of DEGC depends on certain moments of the noise and interference impairing the transmission. We provide closed-form expressions for these moments for practically important types of noise such as Gaussian noise, Gaussian mixture noise, and correlated co-channel interference. In addition, we show that the performance loss of DEGC compared to coherent maximum ratio combining (MRC) is always 3 dB independent of the type of noise if only one diversity branch is available but strongly depends on the type of noise if multiple diversity branches are combined.

In this paper, we present a unified asymptotic symbol error rate (SER) analysis for linearly modulated signals with equal gain combining (EGC) and selection combining (SC) at the receiver. Our analysis is general enough to encompass all commonly used fading models and (possibly) non-Gaussian noise (and interference). We show that for high signal-to-noise ratios (SNRs) the SER of EGC and SC depends on the Mellin transform of the probability density function (pdf) of the noise. Since the Mellin transform can be readily obtained for all commonly encountered noise pdfs, the provided SER expressions are easy and fast to evaluate. Furthermore, we show that the diversity gain of EGC and SC only depends on the fading statistic and the number of diversity branches, whereas the coding gain depends on the modulation format, the type of fading, the number of diversity branches, the type of noise, and the combining scheme. Therefore, in a log-log scale for high SNR the SER curves of EGC and SC for different types of noise are parallel and their relative shift depends on the Mellin transforms of the noise pdfs.

In this paper, we study the asymptotic behavior of the bit-error probability (BEP) and symbol-error probability (SEP) of coherent maximum-ratio combining (MRC) in correlated Ricean fading and non-Gaussian noise, which in our definition also includes interference. We derive simple and easy- to-evaluate asymptotic BEP and SEP expressions which show that at high signal-to-noise ratios (SNRs) the performance of MRC depends on certain moments of the noise and interference impairing the transmission. We provide closed-form expressions for these moments for practically important types of noise such as Gaussian mixture noise, correlated co-channel interference, and correlated Gaussian interference. Interestingly, our results show that not only fading correlation but also noise correlation has an adverse effect on the asymptotic BEP and SEP.

In this paper, we investigate the effect of multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) interference on narrowband (NB) receivers. For this purpose, we first derive the exact moment generating function of MB-OFDM UWB interference. Based on this result, we develop analytical expressions for the amplitude probability distribution (APD) and the bit error rate (BER) of a binary phase-shift keying NB receiver. These expressions can be efficiently numerically evaluated and the presented analysis is general enough to encompass non-fading and various fading NB channels. We show that for NB signals with, respectively, much smaller and much larger bandwidths than the MB-OFDM sub-carrier spacing a Gaussian approximation (GA) and an impulsive GA (IGA) of the MB-OFDM UWB interference lead to accurate performance predictions. However, for most NB channel models and signal bandwidths the exact BER analysis has to be used to obtain meaningful results. An exception is the Rayleigh fading NB channel where both GA and IGA yield tight approximations of the exact BER regardless of the NB signal bandwidth.

In this paper, we provide a unified asymptotic symbol error rate (SER) analysis of linearly modulated signals impaired by fading and (possibly) non-Gaussian noise (and interference). The derived asymptotic closed-form results are valid for a large class of fading and noise processes. In particular, we show that for high signal-to-noise ratios (SNRs) the SER of linear modulation schemes depends on the Mellin transform of the probability density function (pdf) of the noise and the diversity gain of the fading channel. Since the Mellin transform can be readily obtained for all commonly encountered noise pdfs, the provided SER expressions are easy and fast to evaluate.

In this paper, we evaluate the effect of multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra-wide-band (UWB) interference on a narrowband (NB) receiver. For this purpose, we first derive an analytical expression for the exact moment generating function (MGF) of MB-OFDM UWB interference. Subsequently the bit error rate (BER) of a binary phase-shift keying (BPSK) NB receiver impaired by MB-OFDM UWB interference and additive white Gaussian noise is analyzed. We show that for NB signal bandwidths much smaller and much larger than the OFDM sub-carrier spacing a Gaussian approximation (GA ) and an impulsive GA of the MB-OFDM UWB interference leads to accurate performance predictions, respectively. However, for most NB signal bandwidths of practical interest the exact BER analysis has to be used to obtain meaningful results.

In this paper, we evaluate the effect of multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) interference in fading narrowband (NB) channels. We derive the exact bit error rate (BER) of a binary phase-shift keying (BPSK) NB receiver impaired by fading, MB-OFDM UWB interference, and additive white Gaussian noise. We show that for NB signal bandwidths much smaller and much larger than the OFDM sub-carrier spacing a Gaussian approximation (GA) and an impulsive GA (IGA) of the MB-OFDM UWB interference lead to accurate performance predictions, respectively. While for general fading distributions and most NB signal bandwidths of practical interest the exact BER analysis has to be used to obtain meaningful results, both the GA and the IGA are very accurate for Rayleigh fading and arbitrary NB signal bandwidths