Reference Channel Model Research Articles

BER analysis of a full-duplex relay-assisted BPSK-SIM based VLC system for indoor applications.

This paper contemplates a relay-assisted visible light communication (VLC) system, where the light source (table lamp) acts as a relay node and cooperates with the main light source. Following the IEEE 802.15.7r1 VLC reference channel model, we assume that there are two different light sources present in an office room. The first one is the source terminal present on the ceiling and another one is the desk lamp that serves as the relay station, which works in a full-duplex method. Because of the loop interference channel, we model the VLC relay terminal using ray tracing simulations. We have analyzed the bit error rate (BER) performance of the relay-assisted VLC system using a binary phase shift keying-subcarrier intensity modulation (BPSK-SIM) technique. The proposed method outperforms existing phase shift keying (PSK) and square M-quadrature amplitude modulation (M-QAM) techniques. The proposed VLC system using the BPSK-SIM technique achieves a BER performance of 10-12 for an SNR of 20dB. The results of the proposed full-duplex and half-duplex relayed VLC systems are evaluated using equal power allocation (EPA) and optimum power allocation (OPA) techniques over three different modulation schemes, which are 2-PSK, square M-QAM, and BPSK-SIM.

Research on Performance Metrics and Environmental Conditions for 5G MIMO OTA

For Multiple-input, multiple-output (MIMO) user equipment (UE), over-the-air (OTA) testing of radiated multi-antenna reception performance is crucial to guarantee actual network performance and is mandatory in North America, Europe and China. For 5G MIMO OTA, 3GPP has specified the clustered delay line (CDL) channel models as the reference channel models, which present higher order and directivity than those of 4G. Therefore, which kinds of performance metrics and environmental conditions are feasible and necessary to better characterize the MIMO performance should be studied. In this paper, MIMO OTA measurement results of different figures of merits (FoMs) under both UE noise-limited and interference-limited environmental conditions have been compared and discussed, respectively. In addition, the impact of different channel models on MIMO OTA throughput performance as well as the variance per azimuth are compared. Based on the analysis, Peak-Null can better reflect the difference between the 12 azimuth positions than Variance. Total Radiated Multi-antenna Sensitivity (TRMS) under both channel models presents nearly the same performance trends at different thresholds. On the contrary, MIMO Average Radiated SIR Sensitivity (MARSS) exhibits a high dependence on channel models. The MARSS under UMi channel model shows a much smaller performance variation between UEs than UMa channel model. TRMS under 3GPP UE noise-limited environmental condition exhibits a stronger ability to distinguish between good and bad performing devices than that of MARSS under CTIA interference-limited environmental condition. The discrepancy can reach 4 dB at most. This discrepancy does not come from different average manners between TRMS and MARSS, but originates from environmental condition itself. Therefore, it is proposed to adopt TRMS under UE noise-limited environmental condition as the unique or baseline test condition in 5G FR1 MIMO OTA. Peak-Null can be considered as a secondary FoM to characterize the variance per azimuth.

Channel modelling for vehicle‐to‐vehicle MIMO communications in geometrical rectangular tunnel scenarios

This study presents a multiple-input multiple-output (MIMO) statistical channel model for vehicle-to-vehicle (V2V) line-of-sight (LOS) and non-LOS mobile communication system in a rectangular tunnel environment. In order to improve the V2V communication system performance, the authors introduced the elevation and azimuth angles in three-dimensional modelling based on the original literature. In the proposed reference channel model, the single-bounced scattering propagation path of electromagnetic signals is considered and it is assumed that the scatterers are randomly distributed on the rectangular tunnel wall. Starting from the statistical physical channel model, the time-variant transfer functions are derived. Thereafter, the analytical expressions of the space–time–frequency cross-correlation function, the space cross-correlation function, the temporal autocorrelation function, the frequency correlation function, and MIMO channel capacity are derived. The influence of model parameters on the performance of the V2V communication system is also analysed. This work provides an innovative approach to channel modelling in a rectangular tunnel mobile communication environment.

5G Channel Model for 28 GHz frequency in Palembang

Next generation wireless technology require a wide frequency band. Current technology use a frequency of below 3 GHz which cannot provide a wide frequency band due to quite dense frequency utilization. The mm-Wave frequency guarantee to provide a wide band frequency band. The use of mm-Wave frequency will be influenced by climate factors. The characteristics of a place will cause a different channel model. Channel Model is useful for minimizes errors and maximizes information transmission or bitrate in communication model. The Channel Model will be represented as a PDP (Power Delay Profile). Channel model performance uses the Outage performance parameter in Shannon Theorem Implementation. Validation results using the CP-OFDM system with 5G BPSK. The parameters used for validation are FER and BER. In this paper, channel models will be analysed based on the characteristic of Palembang area as a reference channel model in Outer of Indonesia. Hopefully, it can be used as a reference for the development 5G wireless system.

Channel modelling for indoor visible light communications.

Visible light communication (VLC) allows the dual use of light-emitting diodes (LEDs) for wireless communication purposes in addition to their primary purpose of illumination. As in any other communication system, realistic channel modelling is a key for VLC system design, analysis and testing. In this paper, we present a comprehensive survey of indoor VLC channel models. In order to set the background, we start with an overview of infrared (IR) channel modelling, which has received much attention in the past, and highlight the differences between visible and IR optical bands. In the light of these, we present a comparative discussion of existing VLC channel modelling studies and point out the relevant advantages and disadvantages. Then, we provide a detailed description of a site-specific channel modelling approach based on non-sequential ray tracing that precisely captures the optical propagation characteristics of a given indoor environment. We further present channel models for representative deployment scenarios developed through this approach that were adopted by the Institute of Electrical and Electronics Engineering (IEEE) as reference channel models. Finally, we consider mobile VLC scenarios and investigate the effect of receiver location and rotation for a mobile indoor user. This article is part of the theme issue 'Optical wireless communication'.

A Novel Random Angular Sampling Method for Spatial and Temporal Channel Emulation

In this letter, a novel angular sampling method–random offset sampling (ROS) is proposed for the simulation of ray-based physical reference channel models. This new method employs an asymmetrical random angular offset to the equal power sampling method, which makes the simulated channel match the spatial–temporal characteristics of the reference channel model more exactly. It is shown that this new method can make better utilization of the symmetrical property of power angular spectrum distributions with very limited sampling sinusoids, especially performing pretty well in case of small angular spread. With small modifications, ROS can be directly embedded in the state-of-the-art standardized channel simulation models.

Statistical Modeling, Simulation, and Experimental Verification of Wideband Indoor Mobile Radio Channels

This paper focuses on the modeling, simulation, and experimental verification of wideband single‐input single‐output (SISO) mobile fading channels for indoor propagation environments. The indoor reference channel model is derived from a geometrical rectangle scattering model, which consists of an infinite number of scatterers. It is assumed that the scatterers are exponentially distributed over the two‐dimensional (2D) horizontal plane of a rectangular room. Analytical expressions are derived for the probability density function (PDF) of the angle of arrival (AOA), the PDF of the propagation path length, the power delay profile (PDP), and the frequency correlation function (FCF). An efficient sum‐of‐cisoids (SOC) channel simulator is derived from the nonrealizable reference model by employing the SOC principle. It is shown that the SOC channel simulator approximates closely the reference model with respect to the FCF. The SOC channel simulator enables the performance evaluation of wideband indoor wireless communication systems with reduced realization expenditure. Moreover, the rationality and usefulness of the derived indoor channel model is confirmed by various measurements at 2.4, 5, and 60 GHz.

Performance analysis and optimization of unipolar OFDM based relay-assisted visible light communications☆

In this paper, we consider a relay-assisted visible light communication (VLC) system where an intermediate light source cooperates with the main light source. Following the IEEE 802.15.7r1 VLC reference channel model, we assume the presence of two different light sources in an office space. The first one is the ceiling light that serves as the source terminal while the second one is the desk lamp that serves as the relay terminal. Our system builds upon unipolar optical orthogonal frequency division multiplexing (U-OFDM) where the desk light performs amplify-and-forward relaying to assist the ceiling light and operates in a half-duplex mode. In addition, we consider the use of enhanced U-OFDM (eU-OFDM) which doubles the spectral efficiency of U-OFDM at the expense of additional computational complexity. We analyze the bit error rate performance of the relay-assisted VLC system building on these two OFDM types and quantify performance improvements over point-to-point (i.e., no relaying) VLC systems. In an effort to further improve system performance, we investigate optimal power allocation between source and relay terminals.

IEEE 802.15.7r1 Reference Channel Models for Visible Light Communications

The IEEE has established the standardization group 802.15.7r1 “Short Range Optical Wireless Communications”, which is currently in the process of developing a standard for visible light communication (VLC). As with any other communication system, realistic channel models are of critical importance for VLC system design, performance evaluation, and testing. This article presents the reference channel models that were endorsed by the IEEE 802.15.7r1 Task Group for evaluation of VLC system proposals. These were developed for typical indoor environments, including home, office, and manufacturing cells. While highlighting the channel models, we further discuss physical layer techniques potentially considered for IEEE 802.15.7r1.

Experimental Verification of a Plane-Wave Field Synthesis Technique for MIMO OTA Antenna Testing

This paper evaluates the feasibility of a plane-wave field synthesis (PWS) technique for multiple-input multiple-output (MIMO) over-the-air (OTA) test facility, where a reference channel model is implemented. The test facility is based on a fading emulator and an anechoic chamber, equipped with multiple field emulating probes. The test facility emulates a radio channel condition using the PWS technique, based on the spherical wave theory. A simulation tool implementing the MIMO OTA field synthesis based on the PWS technique, named WIN-OTA, is established, where the WINNER II is chosen as the reference channel model. The simulation results show that the PWS technique reproduces the reference channels accurately in terms of envelope distribution, spatial and temporal correlation, and channel capacity. The WIN-OTA implementation was verified by comparing the emulated fields and the throughput from the simulations with the measurements for a practical MIMO OTA test facility. The results support the feasibility and accuracy of the field synthesis technique and the WIN-OTA implementation in MIMO OTA antenna testing.

A Novel Wideband MIMO Car-to-Car Channel Model Based on a Geometrical Semi-Circular Tunnel Scattering Model

In this paper, we present a wideband multiple-input multiple-output (MIMO) car-to-car (C2C) channel model based on a geometrical semi-circular tunnel (SCT) scattering model. From the geometrical SCT scattering model, a reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS) and non-LOS (NLOS) propagation environments. In the proposed reference channel model, it is assumed that an infinite number of scatterers are randomly distributed on the tunnel wall. Starting from the geometrical scattering model, the time-variant transfer function (TVTF) is derived, and its correlation properties in time, frequency, and space are studied. Expressions are presented for the space–time–frequency cross-correlation function (STF-CCF), the two-dimensional (2D) space CCF, the 2D time–frequency CCF (TF-CCF), the temporal autocorrelation function (ACF), and the frequency correlation function (FCF). Owing to the semi-circular geometry, we reduced the originally threefold integrals to double integrals in the computations of the correlation functions, which simplifies the numerical analysis considerably. From the TVTF characterizing the reference model, an efficient sum-of-cisoid (SOC) channel simulator is derived. Numerical results show that both the temporal ACF and the FCF of the SOC channel simulator match very well with those of the reference model. A validation of the proposed model has been done by fitting the delay spread of the reference model to that of the measured channel, which demonstrates an excellent agreement. The proposed channel simulator allows us to evaluate the performance of C2C communication systems in tunnel environments.

An electromagnetic street scattering channel model for outdoor vehicular-to-vehicular communication systems

The vehicular-to-vehicular (V2V) communications have recently received great attention due to some traffic telematic applications that make transportation safer, more efficient, and more environmentally friendly. Reliable traffic telematic applications and services require V2V wireless communication systems to be able to provide robust connectivity. To develop such wireless communication systems and standards, accurate channel models for the V2V communication systems are required. In this paper, a geometric street scattering channel model for a V2V communication system is presented under line-of-sight (LOS) and non-LOS (NLOS) propagation conditions. Starting from the geometric model, a stochastic reference channel model is developed, where the scatterers are uniformly distributed in rectangles in the form of stripes parallel to both sides of the street. A typical propagation scenario for the proposed model is presented, where the buildings and the trees can be considered as scatterers. Analytical expressions for the probability density functions (PDFs) of the angle-of-departure (AOD) and the angle-of-arrival (AOA) are derived. By obtaining the PDF of the total Doppler frequency, the Doppler power spectral density (PSD) and the autocorrelation function (ACF) of the proposed model are also investigated and computed, assuming that the mobile transmitter (MT) and the mobile receiver (MR) are moving, while the surrounding scatterers are fixed. In this respect the underlying radio channel model differs from the traditional cellular channels. We can draw the conclusion that the PDFs of AOD and AOA first increase and then decrease within a certain angle range; the Doppler power spectral density of the signal in the outdoor street environment presents the peak value in fmax. In addition, while the Rice distribution factor is larger, the value of the autocorrelation function increases relatively, the stability of the fluctuation increases correspondingly as well. To validate the reference channel model, its Doppler parameters are compared with those of a real-world measured channel for urban and rural areas. The numerical results show a good fitting of the theoretical results to the computer simulations. In the proposed geometry-based channel model, we not only study the influence of the street scatterers on the performance of V2V communication system, but also broaden the research of the channel modeling of outdoor wireless communication in turn. To evaluate the propagation characteristics of the outdoor V2V communication systems and the simulation of wireless communication system, this paper provides a powerful research tool.

Indoor wireless propagation under line of sight and no line of sight comprehensive channel modeling

This paper mainly deals with the indoor wireless propagation channel under line of sight (LOS) and non-line of sight (NLOS) propagation conditions, introducing the reference model and studing the design and simulation of modeling and the relevant statistical properties. This paper will present a comprehensive and improved indoor reference channel model based on a geometric scattering model. The reference channel model assumes that infinite number of scatterers will be uniformly distributed on the two-dimensional (2D) horizontal plane of a three-dimensional space. This paper also derives analytical expressions for the probability density function (PDF) of the angle-of-arrival (AOA), the Doppler power spectral density (PSD), and the temporal autocorrelation function (ACF) of an electromagnetic arrival signal; it also analyzes the influences of the important parameters of the functions. It presents a highly efficient sum-of-cisoids (SOC) channel simulation model from the unrealistic reference model, also proposes two efficient parameter computation methods for the design of sum-of-cisoids indoor channel simulation model and compares the computing performances of both. It is shown by simulation results that the statistical properties of the sum-of-cisoids channel simulation model match perfectly the reference channel model. It turns out that the indoor reference model can be approximated by an SOC channel simulation model. Meanwhile the channel simulation model can be well applied to evaluate the performance of indoor wireless communication systems. It also extends the research for indoor wireless channel modeling while reduces the realization expenditure.

The Performance Evaluation of IEEE 802.16 Physical Layer in the Basis of Bit Error Rate Considering Reference Channel Models

Fixed Broadband Wireless Access is a promising technology which can offer high speed data rate from transmitting end to customer end which can offer high speed text, voice, and video data. IEEE 802.16 WirelessMAN is a standard that specifies medium access control layer and a set of PHY layer to fixed and mobile BWA in broad range of frequencies and it supports equipment manufacturers due to its robust performance in multipath environment. Consequently WiMAX forum has adopted this version to develop the network world wide. In this paper the performance of IEEE 802.16 OFDM PHY Layer has been investigated by using the simulation model in Matlab. The Stanford University Interim (SUI) channel models are selected for the performance evaluation of this standard. The Ideal Channel estimation is considered in this work and the performance evaluation is observed in the basis of BER.

Cooperative MIMO multicell networks

Recently, the pressing desire to provide cost-effective solutions aimed at supporting high-throughput broadband wireless access with large-scale coverage has significantly changed the notion of the traditional cellular systems. Physical layer cooperation serves as an enabling technology for such a change. In latest cellular networks, neighboring infrastructure stations, such as base stations (BSs) or relay stations (RSs), share their communication resources to create virtual multiple-input multiple-output (MIMO) systems by means of distributed transmission and signal processing. Cooperative processing at the BSs promises to exceed the limits on spectral efficiency imposed by inter-cell interference, thereby allowing ever more aggressive frequency reuse patterns. On the other hand, cooperation between BSs and RSs, as well as among RSs, is expected to extend coverage and capacity of point-to-multipoint links between BSs and mobile stations in a highly economical fashion. However, to achieve such benefits in practice, numerous research challenges have to be still tackled. This special issue has come up with the intention of collecting cutting-edge research achievements in cooperative MIMO multicell systems. For this special issue, we have received 35 manuscript submissions altogether. After a careful review process, 10 manuscripts have been accepted for publication, which cover the following topics for cooperative MIMO multicell networks: channel modeling, power control and scheduling, interference management, protocol design and performance analysis, cost deployment, simulation tools and testbeds. A brief introduction of all the accepted manuscripts is reported in the following. In the manuscript “A Geometrical Three-Ring-Based Model for MIMO Mobile-to-Mobile Fading Channels in Cooperative Networks” by Talha and Patzold [1], a stochastic narrowband MIMO mobile-to-mobile reference channel model is derived in relay-based cooperative networks and exact closed-form expressions for different correlation functions are provided, under isotropic as well as non-isotropic scattering conditions. A stochastic simulation model is drawn from the reference model. It is shown that the cross-correlation functions of the simulation model closely approximate the corresponding ones of the reference model. In the article “Adaptive Coordinated Reception for Multicell MIMO Uplink” by Lu et al. [2], power control and receive beamforming are jointly optimized with adaptive selection of multiple BSs to minimize the total transmit power, under individual signal-to-interferenceplus-noise ratio constraint per mobile station. To reduce the complexity in the large-scale cellular network, a suboptimal algorithm is derived, which exhibits a good trade-off between performance and complexity if the number of the pre-selected BSs is carefully chosen. In the article “Virtual Cooperation for Throughput Maximization in Distributed Large-Scale Wireless Networks” by Abouei et al. [3], a distributed wireless network with K links is con-sidered, where the links are partitioned into M clusters each operating in a subchannel with bandwidth W/M. The power allocation and number of clusters of such a network are optimized for maximization of the throughput as the number of links approaches infinity. In the article “Distributed Cooperative Precoding with Power Control for Cellular Systems with Correlated Antennas at the Receiver” by Vinosh Babu James et al. [4], the authors consider an analytical model for a multicell and multiuser system with receiver-side correlation. A distributed protocol for cooperation amongst the BSs is also proposed. System performance gains measured in terms of mean and cell-edge spectral efficiency values are reported. In the article “Multimode Transmission in Network MIMO Downlink with Incomplete CSI” by Seifi et al. [5], a two-step scheduling algorithm for a cooperative multicell MIMO downlink is proposed: in the first step, joint user and mode selection is performed, whereas, in the second step, feedback and precoder design is carried out by only considering the users selected in the first step. The metric used to perform user and mode * Correspondence: f.verde@unina.it Department of Biomedical, Electronic and Telecommunication Engineering (DIBET), University of Naples Federico II, Naples, Italy Full list of author information is available at the end of the article Verde et al. EURASIP Journal on Advances in Signal Processing 2012, 2012:41 http://asp.eurasipjournals.com/content/2012/1/41

Benefits and Challenges of Deterministic Reference Channel Models

The paper introduces a new paradigm for reference channel models. Current reference channel models are designed as platforms that generate radio channels for testing using random values for their parameters. These parameters follow some pre-established distribution based on process called parameterization, i.e. statistical processing of previous real measurements or accurate ray tracing simulations. The paper argues that random generated channels give either no new insight or even delusive information and should be replaced with the initial set of radio channels that was used for parameterization. Therefore a deterministic reference channel model, as an emulator of previously recorded real radio channels, is proposed and its potential elaborated.

Design of Wideband MIMO Car-to-Car Channel Models Based on the Geometrical Street Scattering Model

We propose a wideband multiple-input multiple-output (MIMO) car-to-car (C2C) channel model based on the geometrical street scattering model. Starting from the geometrical model, a MIMO reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS) and non-LOS (NLOS) propagation environments. The proposed channel model assumes an infinite number of scatterers, which are uniformly distributed in two rectangular areas located on both sides of the street. Analytical solutions are presented for the space-time-frequency cross-correlation function (STF-CCF), the two-dimensional (2D) space CCF, the time-frequency CCF (TF-CCF), the temporal autocorrelation function (ACF), and the frequency correlation function (FCF). An efficient sum-of-cisoids (SOCs) channel simulator is derived from the reference model. It is shown that the temporal ACF and the FCF of the SOC channel simulator fit very well to the corresponding correlation functions of the reference model. To validate the proposed channel model, the mean Doppler shift and the Doppler spread of the reference model have been matched to real-world measurement data. The comparison results demonstrate an excellent agreement between theory and measurements, which confirms the validity of the derived reference model. The proposed geometry-based channel simulator allows us to study the effect of nearby street scatterers on the performance of C2C communication systems.

A Geometrical Three-Ring-Based Model for MIMO Mobile-to-Mobile Fading Channels in Cooperative Networks

This paper deals with the modeling and analysis of narrowband multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) fading channels in relay-based cooperative networks. In the transmission links from the source mobile station to the destination mobile station via the mobile relay, non-line-of-sight (NLOS) propagation conditions are taken into account. A stochastic narrowband MIMO M2M reference channel model is derived from the geometrical three-ring scattering model, where it is assumed that an infinite number of local scatterers surround the source mobile station, the mobile relay, and the destination mobile station. The complex channel gains associated with the new reference channel model are derived, and their temporal as well as spatial correlation properties are explored. General analytical solutions are obtained for the four-dimensional (4D) space-time cross-correlation function (CCF), the three-dimensional (3D) spatial CCF, the two-dimensional (2D) source (relay, destination) correlation function (CF), and the temporal autocorrelation function (ACF). Exact closed-form expressions for different CFs under isotropic as well as nonisotropic scattering conditions are provided in this article. A stochastic simulation model is then drawn from the reference model. It is shown that the CCFs of the simulation model closely approximate the corresponding CCFs of the reference model. The developed channel simulator is not only important for the development of future MIMO M2M cooperative communication systems, but also for analyzing the dynamic behavior of the MIMO M2M channel capacity.

An Effective MIMO–OFDM System for IEEE 802.22 WRAN Channels

We propose a closed-loop multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) transmission scheme appropriate for the IEEE 802.22 wireless regional area network (WRAN) channel environments. The proposed scheme utilizes the Grassmannian beamforming and an antenna selection algorithm to maintain bit-error-rate (BER) performance and to reduce feedback information. To further reduce the feedback information considering the channel property of the IEEE 802.22 WRAN, the proposed scheme employs an extension of the feedback period and subcarrier grouping. Simulation results in the IEEE 802.22 WRAN reference channel models indicate that the proposed MIMO-OFDM transmission scheme achieves superior BER performance and spectral efficiency than open-loop MIMO-OFDM system even considering the feedback overhead of the system.

Modeling, analysis, and simulation of MIMO mobile-to-mobile fading channels

This paper' deals with the modeling, analysis, and simulation of multiple-input multiple-output (MIMO) narrowband fading channels for mobile-to-mobile communications. A stochastic MIMO mobile-to-mobile reference channel model is derived from the geometrical two-ring scattering model under the assumption that both the transmitter and the receiver are surrounded by an infinite number of local scatterers. Using a wave propagation model, the complex channel gains are derived and their statistical properties are studied. General analytical solutions are provided for the three-dimensional (3-D) space-time cross-correlation function (CCF). We show that this function can be expressed as the product of two 2D space-time cross-correlation function (CFs), called the transmit and receive CF. From the non-realizable reference model, a stochastic and a deterministic simulation model are derived using a double sum of complex exponential functions. It is shown how the parameters of the simulation model can be determined for any given distribution of the angle of departure (AOD) and angle of arrival (AOA). In case of isotropic scattering, we present a closed-form solution for the parameter computation problem and illustrate some numerical results concerning the transmit CF. The proposed procedure provides an important framework for designers of future mobile-to-mobile communication systems to verify new transmission concepts employing MIMO techniques under realistic propagation conditions.