Mobile Radio Transmission Research Articles

A quantitative analysis of MIMO channel performance in new generation networks: Prospects and limitations

The objective of this article is to analyze the behavior of channels in mobile radio transmission chains and propose a solution for reducing propagation attenuation and ensuring Quality of Service (QoS) in telecommunications. As network coverage and throughput demands continue to grow, a thorough characterization of channels is essential. The primary contribution of this work is to investigate the different phases of the digital transmission chain jointly to achieve optimal reliability and QoS. Spatial and temporal representations must be considered at the same level when characterizing and modeling MIMO system channels. Accurate and realistic modeling can be achieved through transmission channel characterization in the spatial domain, which is critical in a MIMO context to improve throughput and performance compared to conventional systems. The article explores the behavior of information carriers in the propagation environment and the impact of fading, diversity, multiplexing, and multipath phenomena.

Comparative Analysis of Mobile Signal Propagation Path Loss in Lagos, Nigeria

This research involves comparative analysis of mobile radio transmission path loss models in Lagos state. Lagos, coastal region within an altitude of 38m, and geographical coordinates (63.60N, 3.280E), in the rainforest area of south-western, Nigeria. The measured active base stations propagation measured parameters (for selected areas; Agbowa, Ibeju Imota, Ilupeju, and Surulere in Lagos between 2019 and 2020 from MTN-NG Microsites) recorded between frequency range of 1500- 2500MHz band with a visible line of sight (LOS) in three areas within the state. Stanford University Interim, ECC-33 and COST 231 models were adopted and optimized models were developed and their empirical outcomes revealed standard deviations (SDs) of 1.87, 1.11, and 31.78 respectively at 500m distance from the microsite of average rural areas. For the sub-urban areas, RMSEs (root mean square errors) observed were 39.11, 0.04, and 1.98 and with SD being 33.52, 0.03, and 1.69. More so, for an urban area, it was discovered that the RMSEs obtained for these three models were 34.84, 1.98 and 0.55 with SD of 29.86, 10.27 and 0.47 at same distance of 500m. The implication is that probability of an improved performance is high when optimized models is adopted compared with what is in existence.

Application of iterative decoding systems (UTTCM) to 4G-LTE mobile radio communication network

The mobile communications market has grown at an unprecedented rate and cellular phones have been adopted much faster than any other equipment. At the same time, current systems meet many needs, depending on whether mobility, speed, cost and quality are promoted and ensured ... To meet the ever-increasing demands of consumers. These large capacity demands can only be met by high efficiency and very good optimization of mobile network infrastructures, while taking into account the constraints that are power, bandwidth and limited complexity. The concern to transmit at high rates while being confined to a defined bandwidth has led some researchers to consider the application of iterative channel codes to high spectral efficiency modulations. In order to recover the transmitted data correctly and efficiently. In our paper, we are mainly interested in simulation analysis to improve the performance of 4G-LTE mobile radio transmission, through the use of iterative coding technique, which is efficient and less complex, named UTTCM through three models of channels (EPA, EVA, ETU).

Cyclic interleaving scheme for an IFDMA system

In this paper, a new interleaving scheme for an interleaved frequency division multiple access (IFDMA) system is proposed. The proposed scheme combines the advantages of code division multiple access (CDMA) with maximal length sequence (m-sequence) and orthogonal frequency division multiple access (OFDMA). Multiaccess interference (MAI) among users is eliminated by employing orthogonal carriers, and the intersymbol interference (ISI) due to multipath channels is minimized by using cyclic interleaving. Diversity gain is achieved in the proposed method with maximal ratio combining (MRC) in the case of a Rayleigh environment. Compared to complex multiuser (MU) detection, the detection process in the proposed method is relatively simple. Multipath orthogonality is achieved in the proposed method, avoiding the need for channel equalization. The proposed method is compared with the conventional interleaving employing well-known minimum mean square error frequency domain equalization (MMSE-FDE). The Monte Carlo simulation results prove the superiority of the proposed interleaving over conventional interleaving with MMSE-FDE, showing that the present scheme is suitable for both uplink and downlink mobile radio transmissions.

Blind channel estimation for FBMC‐based PMR transmission

AbstractThe paper presents a blind channel estimation algorithm for an filter bank multicarriers waveform in a fast varying channel context for professional mobile radio transmissions. A fourth‐order power elevation algorithm, followed by an auto‐deconvolution step, directly leading to the channel impulse response estimation, is developed. Simulation results are adapted to the Tetra enhanced data services standard context for hilly terrain propagation model. Copyright © 2016 John Wiley & Sons, Ltd.

Railway automatic safety protection system based on GPS

The automatic protection system of railway safety is designed for the railway construction workers to protect alarm, and the safety protection device by using GPS satellite positioning system to acquire location information of the operating point, through the CTC/TDCS system and computer monitoring system for the running of the train position and the arithmetic distance. Achieving timely and continuously forecasts about the distance of the train which is apart from the operating point to prompt the voice alarm of the approaching train. Using digital technology to realize the function of the traditional analog interphone, eliminates the quality problems of the call. With the GSM-R, mobile wireless transmission channel and terminal technology, it overcomes the restrictions of the analog interphone which influenced by communication distance and more problems of blind areas. Finally to achieve practical, convenient, applicable and adaptable design goals.

Comparative Evaluation of Fading Channel Model Selection for Mobile Wireless Transmission System

This paper compares the performance of Rayleigh, Rician and Log-normal distributions in mobile wireless transmission system. In these distributions link quality cannot be predicted accurately enough to achieve reliable performance because of the unpredictable nature of the time-varying channel at different mobile speeds in sub-urban environment and as a result it will be very difficult to select the appropriate model in the system design for proper implementation. Binary Phase Shift Keying signaling scheme is used to modulate the data to be analyzed for efficient transmission over the three different distributions at mobile speeds of 30 km/h, 60 km/h and 90 km/h at carrier frequency of 900 MHz. Square root raised cosine filter is used to convert the modulated signal to analog signal suitable for transmission. The received bits through the channel without mitigating technique over the three scenarios are analyzed and Bit Error Rate (BER) computed for comparison. The results obtained showed that Rayleigh distribution has the highest BER, while Rician distribution has the BER between the Rayleigh and log-normal at the different speeds considered. This implies that Rayleigh distribution is the best model to be adopted by communication systems engineers.

Real-Time Measurements for Adaptive and Cognitive Radio Systems

Adaptive and cognitive radios (CR) have been becoming popular for optimizing mobile radio system transmission and reception. One of the most important elements of the adaptive radio and CR concepts is the ability to measure, sense, learn about, and be aware of parameters related to the radio channel characteristics, availability of spectrum and power, interference and noise temperature, operational environment of radio, user requirements and applications, available networks and infrastructures, local policies, other operating restrictions, and so on. This paper discusses some of the important measurement parameters for enabling adaptive radio and CR systems along with their relationships and impacts on the performance including relevant challenges.

Role of Ultrasound in Mass‐Casualty Situations

Ultrasound has been accepted as an important initial screening tool for diagnosing severely traumatized patients. The discovery of free fluid in the abdomen and chest can lead to appropriate and timely definitive care. Mass trauma in disasters may occur in remote places where routine radiological diagnostic tools are not available. The portability, small size, light weight, improved quality and low price are advantages of the new hand-held portable ultrasound machines. Focused Assessment Sonography for Trauma (FAST) can be used as a quick adjuvant method for triaging patients. It accurately, and rapidly provides objective information on injured victims, which ultimately aids in assessment, triage and allocation of resources. Furthermore, it can be repeated during transportation. Satellite and mobile wireless transmission of FAST has also been tested using hand-held units. Interpretation of these images was correct in more than 90% of the studied cases. These new developments in technology have a tremendou...

Satellite and Mobile Wireless Transmission of Focused Assessment with Sonography in Trauma

Objectives: Focused assessment with sonography in trauma (FAST) can define life‐threatening injuries in austere settings with remote real‐time review by experienced physicians. This study evaluates vest‐mounted microwave, satellite, and LifeLink communications technology for image clarity and diagnostic accuracy during remote transmission of FAST examinations. Methods: Using a SonoSite, FAST was obtained on three patients with pericardial and intraperitoneal effusions and two control subjects in a remotely located U.S. Army Combat Support Hospital. A miniature vest‐mounted video transmitter attached to the SonoSite sent wireless ultrasound video 20 m to a receiving antenna. The signal was then transferred over VSAT satellite systems at 512 kilobaud per second (kbps), INMARSAT satellite systems at 64 kbps, and over LifeLink on a moving ambulance through a metropolitan wireless traffic–management network. Clarity and absence or presence of effusions were recorded by 15 staff emergency physicians. Results: Average sensitivity, specificity, and accuracy were 87% (95% confidence interval [CI] = 79% to 95%), 85% (95% CI = 81% to 89%), and 86% (95% CI = 82% to 90%) for the Premier Wireless Vest; 98% (95% CI = 97% to 99%), 83% (95% CI = 75% to 91%), and 86% (95% CI = 82% to 90%) for VSAT; 95% (95% CI = 94% to 96%), 70% (95% CI = 58% to 82%), and 75% (95% CI = 70% to 80%) for INMARSAT; and 82% (95% CI = 73% to 91%), 83% (95% CI = 74% to 92%), and 82% (95% CI = 78% to 86%) for LifeLink with clarity of 3.0 (95% CI = 2.7 to 3.3), 2.9 (95% CI = 2.6 to 3.2), 1.3 (95% CI = 1.2 to 1.4), and 2.1 (95% CI = 1.8 to 2.4), respectively. Conclusions: Accuracy correlated with clarity. Roaming vest transmission of FAST provides interpretable, diagnostic imagery at the distances used in this study. VSAT provided the best clarity and diagnostic value with the lighter, more portable INMARSAT serving a lesser role for remote clinical interpretation. LifeLink performed well, and further infrastructure improvements may increase clarity and accuracy.

Satellite and mobile wireless transmission of focused assessment with sonography in trauma.

Focused assessment with sonography in trauma (FAST) can define life-threatening injuries in austere settings with remote real-time review by experienced physicians. This study evaluates vest-mounted microwave, satellite, and LifeLink communications technology for image clarity and diagnostic accuracy during remote transmission of FAST examinations. Using a SonoSite, FAST was obtained on three patients with pericardial and intraperitoneal effusions and two control subjects in a remotely located U.S. Army Combat Support Hospital. A miniature vest-mounted video transmitter attached to the SonoSite sent wireless ultrasound video 20 m to a receiving antenna. The signal was then transferred over VSAT satellite systems at 512 kilobaud per second (kbps), INMARSAT satellite systems at 64 kbps, and over LifeLink on a moving ambulance through a metropolitan wireless traffic-management network. Clarity and absence or presence of effusions were recorded by 15 staff emergency physicians. Average sensitivity, specificity, and accuracy were 87% (95% confidence interval [CI]=79% to 95%), 85% (95% CI=81% to 89%), and 86% (95% CI=82% to 90%) for the Premier Wireless Vest; 98% (95% CI=97% to 99%), 83% (95% CI=75% to 91%), and 86% (95% CI=82% to 90%) for VSAT; 95% (95% CI=94% to 96%), 70% (95% CI=58% to 82%), and 75% (95% CI=70% to 80%) for INMARSAT; and 82% (95% CI=73% to 91%), 83% (95% CI=74% to 92%), and 82% (95% CI=78% to 86%) for LifeLink with clarity of 3.0 (95% CI=2.7 to 3.3), 2.9 (95% CI=2.6 to 3.2), 1.3 (95% CI=1.2 to 1.4), and 2.1 (95% CI=1.8 to 2.4), respectively. Accuracy correlated with clarity. Roaming vest transmission of FAST provides interpretable, diagnostic imagery at the distances used in this study. VSAT provided the best clarity and diagnostic value with the lighter, more portable INMARSAT serving a lesser role for remote clinical interpretation. LifeLink performed well, and further infrastructure improvements may increase clarity and accuracy.

Chip-level differential encoding/detection of spread-spectrum signals for CDMA radio transmission over fading channels

This paper is concerned with the design and performance evaluation of a direct-sequence spread-spectrum transmission and signal-detection technique for application to code-division multiple-access mobile radio networks. Unlike the conventional differential encoding/detection of data symbols, such a technique envisages differential encoding/detection of the spreading code chips to counteract the fast time-selective fading encountered in mobile radio transmissions. Binary PSK modulation on a Rician frequency-flat-fading channel is assumed, with Gaussian and Rayleigh channels as particular cases. The bit-error rate performance of the receiver is analytically evaluated as a function of the relevant system parameters, and the impact on the receiver performance of a carrier frequency offset is also investigated.

Multiple differential detection with adaptive sequence estimation (MDD-ASE)–-mobile radio transmission performance in frequency selective fading environment

This paper aims at the improvement of the transmission performance of the differential detection system in the mobile radio transmission channel in a frequency selective environment. The multiple differential detection with adaptive sequence estimation (MDD-ASE) is proposed, and the performance is analyzed by a computer simulation. In MDD-ASE, not only the differential detection by one-symbol delay but also the differential detection by two- or more-symbol delays are applied. The soft decision is applied to the output of the multiple differential detection, and the symbol sequence is estimated by Viterbi algorithm (VA). The bit error rate (BER) performance is improved by the extended observation time by the multiple differential detection and the sequence estimation. The number of states in VA and the processing complexity of the adaptive algorithm increases exponentially with the extension of the observation time. Consequently, the following method is proposed: (i) the number of parameters to be estimated is reduced; and (ii) the sequence candidates stored in each path of VA are fed back. In this paper, the configuration and operation of MDD-ASE are described first and then the transmission performance of the 40 kbit/s QPSK modulation system is presented. As a result of analysis for the static and the dynamic performances of ADD-MSE using one- and two-symbol differential detection, it is shown that the improvement effect is almost the same as in coherent detection DFE.

An adaptive coding scheme with code combining for mobile radio systems

The authors propose and study an adaptive error-control coding scheme for binary digital FM (BFM) mobile radio transmission. The scheme employs code combining through packet retransmissions. The number of transmissions of a packet is in proportion to the channel fading/noise levels, which is in contrast to time diversity techniques where a fixed number of repetitions of a data packet is performed even in the absence of channel errors. Furthermore, the receiver uses received signal envelopes as channel state information, which significantly improves the throughput and bit error rate (BER) performance. Performance of the proposed scheme is analyzed for frequency-flat Rayleigh fading channels with additive white Gaussian noise (AWGN), co-channel interference and random FM noise.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Envelope, phase and data-transmission characterization for mobile radio channels at UHF frequencies

Presents results of envelope, phase and data-transmission measurements for mobile radio transmissions in the 900 MHz band as well as statistical characterization of the channel-envelope and phase behaviour, of the effect of space diversity, and modeling of error sequences experienced with 20 kb/s BPSK and 10 kb/s differential phase-shift keying (DPSK) data transmission. All experiments were conducted in medium-sized cities, namely Quebec City and Ottawa, and the results show evidence in most cases of a main or direct component superimposed on the multipath components, as is typical of a Rice channel, rather than the fully random behaviour of Rayleigh channels. Actual recordings of the error sequences indicate that the error-generation process is well characterized by Fritchman's channel model consisting of two to four error-free states and a single error state, and the authors conclude by presenting typical values of Fritchman parameters as a function of different values of the mean error rate.

Digital multicarrier‐transmission of audio signals over mobile radio channels

AbstractThis paper presents a systematic overview over different concepts of multicarrier‐trans‐mission under the specific aspect of mobile radio transmission. It will be shown that under realistic multipath channel conditions the postulation of ideal bandwidth efficiency has to be given up. As a consequence sub‐optimum multicarrier concepts are regarded and mutually compared under the aspects of intersymbol interference and adjacent channel interference. A specific impuls shaping concept based on time and frequency concentrated impulses (Gaussian shaping) turns out as an appropriate solution since hereby the adjacent channel interference can be largely suppressed at the expense of a small increase in intersymbol inference. The performance of the different multicarrier concepts is illustrated by various simulation results under mobile radio channel conditions.

An equalizer with carrier‐acquisition‐during‐training (CAT) algorithm for mobile radio

AbstractThis paper investigates an adaptive equalizer with carrier frequency offset compensation for digital mobile radio transmission over several tens kbit/s. The performance of conventional adaptive equalizers for mobile radio severely degrades for receiving signals having carrier frequency offset which is caused by local oscillator frequency offset due to misadjustment, temperature dependence, and aging.Carrier frequency offset compensation for TDMA burst signaling requires both accurate and short‐time measurements. However, both requirements have a tradeoff relationship and must be optimized.This paper proposes the carrier‐acquisition‐during‐training (CAT) algorithm for transmissions allowing a training signal. First, two basic configurations and their equivalence are discussed. Next, computer simulations and real‐time experiments with one‐chip DSP show the effectiveness of CAT by demonstrating training convergence, optimum parameter characteristics, and average BER performance under two‐path selective fading with one‐symbol delay difference and independent Rayleigh components.

Solar effects on communications

When people involved in the power industry think of Solar Magnetic Disturbances (SMD), they normally consider the potential for disrupting power transmission which results form solar-induced disturbances to the earth's magnetic field known as geomagnetic storms. However, in addition to the disruption of power transmission, solar phenomena can interfere with utility communication systems. Utilities use many different types of communication media, some of which can be affected by various solar phenomena. These include wire-based facilities (metallic cables and power line carrier), radio systems (HF, VHF, UHF mobile radio, microwave networks, and satellite transmissions), and fiber optic systems. This paper reports that the solar flares and other solar phenomena can affect these media through different mechanisms: Radio communications can be disturbed by flare-induced changes in the ionispheric layer of the atmosphere; Cable communications can be disrupted by the flare-induced changes in the magnetosphere which surrounds the earth. These changes, in turn, induce currents in the power equipment that energizes long communications cables; Satellite communications can be disrupted by the flare-induced perturbations of satellite orbits and equipment.

Performance of a new adaptive diversity-equalisation for digital mobile radio

A new adaptive diversity-equalisation suitable for mobile radio signal transmission in the mobile radio fast fading environment is proposed. Adaptivity of the diversity-equalisation is enhanced by employing the recursive least-squares algorithm (RLS) with exponential weighting and two newly proposed techniques: bi-directional equalisation (BDE) and transmitter time-diversity (TTD). Computer simulation shows that QPSK transmission performance equivalent to that of four-branch diversity can be obtained with small impairment.

A novel demodulator/detector for digital and analog signals on LMR channels

The design, implementation, and performance of an all-digital demodulator/detector suitable for differential phase-shift keying (DPSK), continuous-phase frequency-shift keying (CPFSK), frequency-shift keying (FSK), and analog FM are discussed. In this modulator/detector, two detectors, one noncoherent and another differentially coherent, operate simultaneously to provide data detection and automatic frequency control (AFC). Test results indicate that the system provides improved performance over the conventional analog quadrature detector for two-period raised-cosine (2RC) CPFSK modulation in additive white Gaussian noise (AWGN) and Rayleigh fading channels. Being all-digital, the demodulator/detector is well suited for integrated circuit implementation. In addition, the system performs as well as the analog quadrature detector for analog FM voice transmissions, thereby maintaining full compatibility with analog land mobile radio (LMR) transmissions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>