Signal-to-interference-plus-noise Ratio Analysis Research Articles

On energy conservation for fixed-wing UAV assisted practical full-duplex relaying with service requirement and bank angle limit

This paper studies a full-duplex (FD) amplify-and-forward relaying, where a fixed-wing unmanned aerial vehicle (UAV) is dispatched as a mobile relay to serve a source-destination communication pair so as to satisfy their service requirement. Here, the UAV relay flies in a circular path and hence it must continuously change its heading of flight which leads to a bank angle of the aircraft. In order to ensure flight safety, therefore, a bank angle limit is imposed on the UAV relay. By considering a practical FD relaying, namely, there exists both residual loop interference (RLI) and processing time-delay at the relay side, novel signal to interference plus noise ratio (SINR) received at the destination is analyzed, giving a closed-form expression in addition to a concise lower-bound. Armed with the SINR analysis, the size of data received by the destination during a period of flight time of the UAV is calculated, leading to a closed-form lower-bound of the size of data. Taking bank angle limit into consideration and using the calculated lower-bound of the size of data, an optimization problem with the purpose of energy conservation is solved, leading to a novel method for joint adjustment of the UAV's flight parameters. Computer simulation experiments are conducted, and the results demonstrated that the proposed optimization method performs better in terms of energy conservation compared to the benchmark techniques regardless of the value of RLI and/or the service requirement of the source-destination communication pair.

Precoding Design for Multi-Group MIMO-NOMA Scheme With SIC Residual Analysis

This paper presents a precoder design for multiple-input multiple-output (MIMO) uplink communications with a multi-group non-orthogonal multiple access (NOMA) scheme. In this scheme, QR-decomposition-based detection is used to decode user signals of each group under imperfect successive interference cancellation (SIC). In the uplink, transmitted signals are encoded with the constellation of a symmetric quadrature amplitude modulation (QAM), and SIC residual errors are generated from symbol demodulation. The statistics of the SIC errors are derived, with which expressions of approximate SIC-residual-power coefficient and signal-to-interference-plus-noise ratio (SINR) are developed. Consequently, the effect of the SIC errors can be explicitly addressed in the precoder design for minimizing the total transmit power subject to users' symbol error probability (SEP) constraints. A suboptimal design algorithm with efficient “logarithmic” golden-section search is developed. Simulation results show the effectiveness of the design criterion and algorithm, and validate the detection error analysis. Unlike the conventional fractional-SIC-error model that suffers from underestimation/overestimation of SIC errors and infeasibility, our SIC error model can provide accurate effect of the SIC errors in the SINR analysis and enable the proposed method to give design solutions to satisfy the SEP constraints.

MIMO Multifunction RF Systems: Detection Performance and Waveform Design

This paper studies the detection performance of a multiple-input-multiple-output (MIMO) multifunction radio frequency (MFRF) system, which simultaneously supports radar, communication, and jamming. We show that the detection performance of the MIMO MFRF system improves as the transmit signal-to-interference-plus-noise-ratio (SINR) increases. To analyze the achievable SINR of the system, we formulate an SINR maximization problem under the communication and jamming functionality constraint as well as a transmit energy constraint. We derive a closed-form solution of this optimization problem for energy-constrained waveforms and present a detailed analysis of the achievable SINR. Moreover, we analyze the SINR for systems transmitting constant-modulus waveforms, which are often used in practice. We propose an efficient constant-modulus waveform design algorithm to maximize the SINR. Numerical results demonstrate the capability of a MIMO array to provide multiple functions, and also show the tradeoff between radar detection and the communication/jamming functionality.

SINR Analysis of Different OFDM-Inspired Waveforms Over Doubly Dispersive Channels

Wireless channels generally exhibit dispersion in both time and frequency domain, known as doubly selective or doubly dispersive channels. To combat the delay spread effect, multicarrier modulation (MCM) such as orthogonal frequency division multiplexing (OFDM) and its universal filtered variant (UF-OFDM) can be employed, leading to a simple per-subcarrier one tap equalization. The time-varying nature of the channel, in particular, the intra-multicarrier-symbol channel variation induces spectral broadening and thus inter-carrier interference (ICI). Most existing works address both effects separately, focusing on the one effect while ignoring the respective other. This paper considers both effects simultaneously for cyclic prefix (CP)-, zero padded (ZP)- and universal filtered (UF)-based OFDM with a simple one tap equalization, assuming doubly dispersive wireless channel model. For this general channel model, we show that the independent (wide sense stationary uncorrelated scatter, WSSUS) selectivity in time and frequency domain starts to intertwine in contrast to the ideal cases with single selectivity. We derive signal-to-interference-plus-noise ratio (SINR) in closed form for arbitrary system settings and channel parameters, e.g., bandwidth, delay- and Doppler-spread. With the SINR analysis, we compare the three MCM schemes under different channel scenarios.

A Unified Framework for SINR Analysis in Poisson Networks With Traffic Dynamics

We study the performance of wireless links for a class of Poisson networks, in which packets arrive at the transmitters following Bernoulli processes. By combining stochastic geometry with queueing theory, two fundamental measures are analyzed, namely the transmission success probability and the meta distribution of signal-to-interference-plus-noise ratio (SINR). Different from the conventional approaches that assume independent active states across the nodes and use homogeneous point processes to model the locations of interferers, our analysis accounts for the interdependency amongst active states of the transmitters in space and arrives at a non-homogeneous point process for the modeling of interferers’ positions, which leads to a more accurate characterization of the SINR. The accuracy of the theoretical results is verified by simulations, and the developed framework is then used to devise design guidelines for the deployment strategies of wireless networks.

SINR Analysis and Interference Management of Macrocell Cellular Networks in Dense Urban Environments

The increasing growth of wireless applications leads to the congestion of radio spectrum below 10 GHz. This has slowed down the growth of high data rate applications due to the limited bandwidth of currently used frequency bands. This prompted wireless service providers to look for 30–300 GHz frequency band for mobile Broadband and enhanced mobile Broadband services. In this paper, the performance of 5G cellular networks at 30 GHz frequency by suppressing the interference caused by multiple transmissions from potential interferers sharing the same physical medium has been studied. Here initially the appropriate interference model that can predict the outage events in 5G cellular networks in any scenario has been investigated. Next using a cellular network site in dense urban environment with high traffic loads, user density and pedestrian and vehicular movement was created. The signal-to-interference-plus-noise ratio (SINR) is visualized for different antenna systems on a map using real geospatial information. The SINR maps of single antenna element and antenna array are plotted and compared. Both Free-space propagation model and Close-in-Propagation model are used to compare the results. Also using a uniform planar array of antennas on network-side the directionality increases hence interference reduces and higher values of SINR are achieved.

Recursive Carrier Interferometry Aided High Data Rate OFDM Systems With PAPR Suppression, Phase Noise Rejection, and Carrier Frequency Offsets Compensation

In this paper, we propose two groups of recursive codes, namely the Hadamard recursive carrier interferometry (HRCI) codes and diagonal recursive carrier interferometry (DRCI) codes, to simultaneously reduce the peak-to-average power ratio (PAPR) and suppress the phase noises and residual carrier frequency offset (RCFO) for high-speed orthogonal frequency division multiplexing (OFDM) systems. We exploit the recursion property of the Hadamard and diagonal matrices to constitute the proposed HRCI code and DRCI code using the carrier interferometry (CI) code, and present the system model in details to spread OFDM symbols in the frequency domain. Then, we prove that both HRCI and DRCI generation matrices keep their invertibility during the recursions. As a direct result of the new code design, the phase intervals are enlarged and the signals are shifted in the time domain, thus both the PAPR and the phase noises are reduced, and the RCFO can be mitigated. Moreover, the enlarged phase intervals enable the transceiver blocks including the channel estimator, which estimate the phase noise based on the received signals, to improve the performance. Furthermore, we present the expressions for the HRCI and DRCI embedded transmitted and received signals, and derive the analytical signal-to-interference-plus-noise ratio (SINR) expressions for bit error rate (BER) performance analysis. Then, we analyze the effects of presented codes on the phase differences and provide the computational complexity analysis. Numerical simulations verify the effectiveness of our theoretical analysis of SINR. Additionally, under different parameter settings, which consider the working conditions of practical systems, we demonstrate that the presented robust HRCI and DRCI coded OFDM systems can suppress the PAPR satisfactorily and better BER performances can be achieved by the recursive CI-aided spread OFDM systems with phase noise rejection and RCFO compensation when compared with counterpart systems.

On the Energy Efficient Multi-Pair Two-Way Massive MIMO AF Relaying With Imperfect CSI and Optimal Power Allocation

In this paper, we consider multipair two-way massive multiple-input and multiple-output (MIMO) communication system, in which multiple pairs of source nodes exchange messages with the help of one shared amplify-and-forward relay provisioned with large number of antennas. Unlike the perfect channel state information (CSI) assumption, the practical minimum mean-squared error-based channel estimation is considered. And the asymptotic signal to interference plus noise ratio (SINR) analysis of four power-scaling scenarios is presented to show that, even with the imperfect CSI, the interpair interference can still be eliminated, the small-scale fading as well as the noise at source nodes and the relay can be averaged out in the regime of very large number of antenna. It is unveiled that the impact of the channel estimation error will present in the effective large-scale fading coefficient, which explicates the degradation by the imperfect CSI estimate and consumes the results with perfect CSI as special cases. On the basis of the asymptotic SINR analysis results, the optimal power allocation problem is formulated to derive the energy efficient relaying scheme for the maximum ratio combining-maximum ratio transmission precoding scheme. Finally, numerical results are presented to validate that the energy efficient design can effectively reduce the power consumption while maintaining a reasonable sum rate in the multipair two-way massive MIMO relaying system, even in the presence of CSI error.

Bit error rate analysis of generalised frequency division multiplexing with weighted‐type fractional Fourier transform precoding

Generalised frequency division multiplexing (GFDM) as a non-orthogonal waveform candidate is posed to reduce the high out of band radiation of orthogonal frequency division multiplexing system via pulse shaping. In this study, an analytical model of introduced interference from neighbouring subcarriers caused by pulse shaping is firstly proposed. Signal-to-interference-plus-noise ratio (SINR) is calculated according to related GFDM models with different weighted-type fractional Fourier transform (WFRFT) precoding orders. Approximated bit error rate (BER) expressions are derived for the low complexity GFDM system over additive white Gaussian noise and fading channels based on the analysis of SINR. Particularly, the BER superiority of WFRFT precoding is highlighted over the fading channels. Furthermore, peak-to-average power ratio and out of band power suppression performances are simulated at different WFRFT orders to illustrate the advantages of WFRFT precoding.

Downlink Performance Analysis for a Generalized Shotgun Cellular System

In this paper, we analyze the signal-to-interference-plus-noise ratio (SINR) performance at a mobile station (MS) in a random cellular network. The cellular network is formed by base stations (BSs) placed in a one-, two-, or three-dimensional space according to a possibly non-homogeneous Poisson point process, which is a generalization of the so-called shotgun cellular system. We develop a sequence of equivalence relations for the SCSs and use them to derive semi-analytical expressions for the coverage probability at the MS when the transmissions from each BS may be affected by random fading with arbitrary distributions as well as attenuation following arbitrary path-loss models. For homogeneous Poisson point processes in the interference-limited case with power-law path-loss model, we show that the SINR distribution is the same for all fading distributions and is not a function of the base station density. In addition, the influence of random transmission power, power control, and multiple channel reuse groups on the downlink performance is also discussed. The techniques developed for the analysis of SINR have applications beyond cellular networks and can be used in similar studies for cognitive radio networks, femtocell networks, and other heterogeneous and multi-tier networks.

Exact pre‐scheduling SINR analysis for per‐user unitary rate control systems

The exact probability density function (PDF) of the pre-scheduling signal-to-interference-plus-noise ratio (SINR) for per-user unitary rate control (PU2RC) systems is derived. A main contribution is proposing a novel dimension-reducing-type function to resolve the key problem, i.e. within a multi-dimensional complex space, to obtain the PDF of a unit isotropic vector's maximum projection on vectors of an orthonormal basis. Even if PU2RC systems are only considered, the proposed function is quite useful for the analysis of other orthogonal beams-based MIMO systems as well. Monte Carlo simulations validate the analysis results.

SINR and Throughput Analysis for Random Beamforming Systems with Adaptive Modulation

In this paper, we derive the exact probability distribution of post-scheduling signal-to-interference-plus-noise ratio (SINR) considering both user feedback and scheduling. We also develop an optimized adaptive modulation scheme in orthogonal random beamforming systems with M transmit antennas and K single-antenna users. The exact probability distributions of each user's feedback SINR and the exact post-scheduling SINR are derived rigorously by direct integration and multinomial distribution. It is also shown that the derived cumulative distribution function (CDF) of the post-scheduling SINR happens to be identical to the the existing approximate CDF for SINR higher than 0 dB. The closed form expressions of system performance, such as average spectral efficiency (ASE) and average bit error ratio (A-BER), are derived using the CDF of the post-scheduling SINR. The optimal SINR thresholds that maximize the ASE with a target A-BER constraint are solved using the derived closed form CDF and a Lagrange multiplier. Key contributions of this paper include the derivation of the exact CDF of post-scheduling SINR by direct integration, and its application to an optimized adaptive modulation based on a Lagrange multiplier. Simulations show the correspondence between theoretical and empirical CDF's, and the performance improvement of the proposed adaptive modulation method in terms of ASE.

Exact post-scheduling SINR analysis for orthogonal random beamforming systems

Derived are the exact cumulative distribution functions (CDFs) of each user's feedback signal-to-interference-plus-noise ratio (SINR), and the post-scheduling SINR in orthogonal random beamforming systems with M transmit antennas and K single-antenna users considering both user feedback and scheduling. A key contribution is to derive the exact CDF of the post-scheduling SINR by direct integration, and it is verified by Monte-Carlo simulations. It is also shown that the existing approximate CDF is different from the exact distribution for SINR smaller than 0 dB.

SINR Analysis of Hexagonal Multicarrier Transmission Systems in the Presence of Insufficient Synchronization for Doubly Dispersive Channel

This paper analyzes the effect of the insufficient synchronization (carrier frequency offset, timing offset) on hexagonal multicarrier transmission (HMT) systems for doubly dispersive channel. Exact SINR and demodulated symbol expressions for HMT systems in the presence of insufficient synchronization transmission conditions over doubly dispersive channel with exponential delay power profile and U-shape Doppler power spectrum and uniform delay power profile and uniform Doppler power spectrum are derived, respectively. Theoretical analysis shows that similar degradations on symbol amplitude and phase caused by insufficient synchronization are incurred as in traditional cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) transmission. HMT systems outperform traditional OFDM systems with respect to signal to interference-plus-noise-ratio (SINR) against inter-symbol interference (ISI) and inter-carrier interference (ICI) caused by insufficient synchronization and doubly dispersive(DD) channel. The BER performance of the HMT systems using Monte Carlo simulation match with the conclusion given by the proposed exact SINR expression.

Exact SINR analysis of wireless OFDM in the presence of carrier frequency offset

This paper presents a new mathematical analysis for the evaluation of the average signal-to-interference plus noise ratio (SINR) of orthogonal frequency division multiplexing (OFDM) in the presence of carrier frequency offset (CFO). CFO destroys the orthogonality between different subcarriers giving rise to inter-carrier interference (ICI). The SINR of wireless OFDM in the presence of CFO and frequency-selective fading becomes a ratio of correlated random variables, and the exact evaluation of its average by using direct methods requires a huge computational effort. In this paper, we present an indirect method that leads to a new exact simpler expression for the average SINR over Rayleigh multipath fading channels.

Average SINR Analysis of DS-BPSK UWB Systems With IPI, ICI, ISI, and MAI and Its Application

Analytical expressions for the average output signal-to-interference-plus-noise ratio (SINR) of direct-sequence (DS) binary-phase-shift-keying (BPSK) ultra-wideband (UWB) receivers are derived using the IEEE UWB channel models. The derivation takes into account the interpath interference, the interchip interference (IPI), the intersymbol interference (ISI), and the multiple-access interference (MAI). The effects of the spreading gain and the pulse duration on the average output SINR are examined. Using these results, the optimal integration interval for a transmitted reference UWB receiver is studied.

Frequency domain discrete fourier transform spread generalized multi-carrier system and its performance analysis

Discrete fourier transform spread generalized multi-carrier (DFT-S-GMC) scheme is a promising candidate for the uplink transmission of the new generation broadband mobile communications due to its lower peak-to-average power ratio and its robustness to the multi-user interference if compared with the conventional orthogonal frequency division multiple (OFDM)-based transmission schemes. However, the time domain DFT-S-GMC system has a relatively high implementation complexity and is difficult to analyze its signal-to-interference plus noise ratio (SINR). In addition, the existing link-to-system mapping methods for OFDM-based systems cannot be utilized in the DFT-S-GMC systems. In this paper, we first propose a novel frequency domain transceiver model for the DFT-S-GMC system, which can effectively simplify the SINR analysis. Then, we derive the closed-form SINR expressions for the link-to-system mapping of DFT-S-GMC system with Alamouti-like space–time block-coding (STBC). It is demonstrated that the theoretical SINR expressions match the simulation results very well.

Analysis of Channel-Averaged SINR for Indoor UWB Rake and Transmitted Reference Systems

In this paper, we derive a closed-form expression for channel-averaged signal-to-interference-plus-noise ratio (SINR) for ultra-wideband (UWB) Rake receiving system in an indoor multiuser communication scenario, given that the interference level is fluctuating due to asynchronous transmissions among users. The indoor wireless channel model adopted here is a standard one, recently released by IEEE 802.15 study group 3a . We propose a theoretical framework to derive the channel-averaged SINR considering the lognormal channel gain distribution and the double independent Poisson arrival distribution of cluster and ray, and show that our analysis is well coincident with the simulation results. With this framework, we demonstrate that our analysis can be applied to theoretically determine the optimum integration interval for a UWB transmitted reference system, even in a multiuser scenario.

Performance analysis of multicarrier CDMA systems with frequency offsets and random spreading under optimum combining

The carrier-frequency offset effect on the performance of asynchronous multicarrier direct-sequence code-division multiple-access (MC-DS-CDMA) systems with aperiodic random spreading and correlated Rayleigh fading is studied in this paper. We obtain the optimum combining filter that maximizes the signal-to-interference-plus-noise ratio (SINR) of the combined statistics and exploits correlated information among subchannels. A closed-form expression for the unconditional covariance matrix of the interference-plus-noise vector, which forms the basis of our theoretical analysis of the maximum SINR and the average bit error probability formula, is derived by averaging several random parameters including asynchronous delays, correlated Rayleigh fading, and signature sequences. The analytic results obtained are applicable to MC-CDMA with appropriate modifications. Furthermore, we show that the MC-CDMA system with a common random signature sequence over all subcarriers for a given user outperforms that with distinct sequences over different subcarriers. Finally, the performance of MC-CDMA systems using the optimum combining technique is compared with that of different combining filters in the simulation.