Optimization of the Coverage Area for DVB-T Single Frequency Networks Using a Particle Swarm Based Method

In this work, the usefulness and limitations of a planning tool that combines a propagation prediction method and a modern heuristic technique when applied to improve the coverage area in single frequency networks (SFN) is presented. The propagation prediction method uses 3D digital terrain maps along with a propagation model to estimate the contribution of any transmitter of the SFN at each location within the region in which the SFN is intended to be deployed, given in terms of parameters such as the received power and propagation delay. Furthermore, a particle swarm optimization (PSO) algorithm is used to optimize the transmission parameters of any of the transmitters within the SFN, including transmitters delay or gain for their sector antennas, in order to exploit the multipath tolerance in OFDM receivers. Preliminary results comparing the performance of different PSO schemes considering as the canonical problem a SFN consisting of eighteen transmitters, in which transmitters and receivers have been simplified, are reported and discussed. Moreover, results considering sector and directive antennas at the transmitter and receiver sides, respectively, are also included.

The problem of near-optimal test point set selection with imperfect test is solved by using the heuristic particle swarm optimization (HPSO) algorithm. First, to describe the uncertainty of each test, the testability analysis model and such indexes as fault detection rate, fault isolation rate, and false alarm rate are redefined. A heuristic function is then established to evaluate the detection isolation capability and uncertainty of the test point, which can provide heuristic information to improve the searching efficiency of particle swarm optimization (PSO). The heuristic function and least test cost principle are used as bases to design a fitness function of PSO algorithm for test point selection. Finally, the HPSO algorithm is proposed to select the optimal test point set for two practical systems. Simulation and experiment results show that the method can determine the global optimal test point accurately and effectively while meeting the requirements of testability indexes with least cost.

A heuristic particle swarm optimization algorithm is proposed to solve the problem of test point selection with unreliable test. Firstly, a heuristic function is established to value the capability of test point detection, coverage and reliance. Then based on the heuristic function and least test cost principle, a fitness function of unreliable test is created. Lastly, the method for test point selection using improved particle swarm optimization algorithm is presented. Comparing with other method of test point selection, the results show that the method is easy to find the global optimal test point in large-scale system. It can also minimize test cost on requirement of testability targets.

DVB-T2 broadcasting with a single frequency network (SFN) allows an efficient management of frequency utilization and extends the coverage area, which will enable more people to view a broadcast. The SFN mode also increases the concentration of the signal in overlap areas. However, some difference of overlap areas in actual use of SFN networks may have some degradation of the received signal due to the effect of the SFN. In this research, we analyze SFN broadcasting in SISO mode. This paper represents the effects of delays on the SFN signal over different delay times within the guard interval (GI) by analyzing the minimum reception threshold. The analysis of received signal power, MER, bBER, LBER, and noise margin are studied using an actual digital television transmitter for the experiment. The results show that the minimum thresholds for a delay time at 0 microseconds will require higher receive signal power than other delay times within the GI. The results of this experiment are useful in designing the SFN network and make it possible to determine the appropriate C/N threshold for the design of the digital terrestrial television network.

OFDM is expected to be a suitable modulation method for digital terrestrial broadcasting systems. One of the reasons is that it makes it possible to construct a single frequency network (SFN) and to make effective use of the frequency bands. In a SFN environment, however, some receivers will obtain their signals from more than one transmitter. This causes two effects, intersymbol interference and degradation of frequency characteristics due to echoes. This paper describes a theoretical study on the latter effect in a variety of signal numbers, D/U ratios and delays arriving at the receiving antenna and the BER (bit error rate) distribution within the coverage area of SFNs in a variety of the transmitter numbers with computer simulations on a virtual plain. Finally we suggest a method to improve the quality in a coverage area.

Single frequency networks (SFN) broadcast is an efficient method to provide broadcast services in cellular networks. How to select broadcast services by the SFN operation to trade off between the occupied bandwidth and the SFN performance including spectrum efficiency and broadcast service continuity is a new problem. To the best of our knowledge no solutions have been proposed to solve this problem so far in the literature. We define the problem of SFN broadcast services selection as a knapsack problem and solve it to minimize the occupied bandwidth while at the same time guaranteeing the SFN performance. Based on the solution, several SFN broadcast services selection algorithms are proposed which vary in the reselection policy. Numerical results show that our proposed algorithms are applicable to different cases with different system requirements and in particular, that the semi-dynamic-SFN broadcast services selection algorithm is an efficient solution in general.

This paper presents the results of laboratory tests simulating the reception in a Single Frequency Network (SFN) with ATSC on commercial receivers. The results of the commercial receivers are important because the viability of the SFNs with ATSC depends mainly of the performance of the receivers. Additionally, the basic implications of the results on the SFNs design are presented. Mexico officially adopted ATSC for Digital Terrestrial Television (DTT) service more than 10 years ago, but the analog transmissions stopped until December 31, 2015. The results of these tests can contribute to the planning of SFNs with ATSC. ATSC does not use OFDM modulation unlike others DTT systems. For this reason, the operation of a SFN with ATSC depends primarily on receiver equalizer capabilities. However, the performance of the receivers have improved over the years. The tests focus on the relationship between power and delay of the two signals received on the SFN, and the methodology includes the simulation of three reception environments: without multipath, outdoor reception and indoor reception.

Digital terrestrial television systems (DVB-T) using single frequency networks (SFN) based on OFDM modulation schemes have been deployed during the last years. Such SFN topology make it possible to increase the number and quality of services offered due to their more efficient use of the spectrum compared to multiple frequency networks (MFN). Moreover, SFN can cut down on the number of transmitters along with their powers because of the internal gain of the network, saving overall deployment and maintenance costs, and even achieving coverage improvements or a decrease of the outage probability over larger geographical areas through the reuse of frequencies. In this work, an approach to analyze and improve the coverage of a SFN over the most populated regions with the least possible economic investment is proposed, considering several strategies to synchronize and combine the signals at the receiver side and using a hybrid algorithm, mixing up the real and binary versions of the Particle Swarm Optimization algorithm (PSO), to optimize the static delays, gains and orientations for each SFN transmitter and decide whether each sector antenna must be active or not.

Single Frequency Network(SFN) transmission mode in Long Term Evolution(LTE) can be used to deliver Multimedia Broadcast Multicast Service(MBMS) business in the form of sharing wireless resources. It has negative effect on the spectral efficiency while the allocation of resources in SFN mode refers to the worst signal user. This paper introduces a novel transmission mode named Mixture Mode(MIX) for MBMS transmission, and proposes an optimized switching mechanism denominated MIX-SFN-PTP(MSP) to dominate the switching among MIX, SFN and Point-to-point(PTP). PTP and SFN are incorporated in MIX, and a fast-select algorithm working in a greedy manner is designed to determine the ways in which users receive the MBMS business. MIX and MSP are evaluated through simulation experiments. The results show that MIX is able to obtain higher spectral efficiency compared with SFN transmission mode, and MSP can economize more wireless resources than traditional algorithm in the case that users have subpar signal.

The single frequency network (SFN) has been assumed worldwide by telecommunication operators to save radio frequency resources and homogenize the network. Its applications have transcended the digital terrestrial television and digital radio to become part of the key techniques of the broadband and broadcast convergence for LTE-A, 5G and beyond. However, the transition from a multi frequency network (MFN) to an SFN involves multiple measurement campaigns and tuning of the network to achieve the expected up-performance and quality of service. This paper aims to propose a machine learning model to predict the SFN performance from the legacy MFN parameters. The model is based on regression and classification machine learning algorithms concatenated in three consecutive stages to predict SFN electric-field strength, modulation error ratio and gain. The training and test processes are performed with a dataset of 389 samples from an SFN/MFN trial in Ghent, Belgium. The best performance is obtained with concatenating gradient boosting, random forest, and linear regression, which allows predicting the SFN electric-field strength with an R-2 of 92%, the modulation error ratio with 95%, and SFN gain with 87% from only MFN and position data. Besides, the model allows classifying the data points according to positive or negative SFN gain with an accuracy of 93%.

Terrestrial broadcasting signals have been recognized as promising candidates for positioning and navigation needs. However, in some terrestrial broadcasting networks, which are usually single frequency networks, the transmitter confusion problem poses a huge obstacle to almost all positioning algorithms. Without knowing the transmitter identities, measurements can't be associated to transmitters coordinates properly, thus leaving receiver coordinates unable to be estimated. Meanwhile, as the exact transmission delay is usually hard to estimate, the time difference of arrival (TDoA) based positioning is widely used. In this paper, a novel TDoA based localization method is proposed to realize positioning in single frequency networks. With the proposed method, the receiver can estimate its own position when transmitter identities are missing from the signals. Simulation results verify the feasibility and accuracy of the method and discussions regarding its properties are given.

In a Single Frequency Network (SFN) for Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, the interferences induced by the multiple transmitters and/or repeaters using same frequency are unavoidable. To ease the interference handing in the SFN for ATSC DTV system, transmitter identification (TxID) signal is recommended in the ATSC terrestrial DTV system. The TxID signal is embedded in the ATSC DTV signal and transmitted from each transmitter and repeater within the SFN and in ATSC recommended practice (RP) A/111, Kasami sequence is recommended as the TxID signal. In this paper, we propose an additional data transmission scheme using the TxID signal. In the proposed scheme, the Kasami sequence not only acts as the conventional TxID of the SFN for ATSC terrestrial DTV system but also carriers the additional data bits on its polarity and the code phase.

DVB-T2, second generation of terrestrial digital video broadcasting standard, promises performance gains because of improved coding, modulation and multiple antenna technologies. This paper proposes a simulation and evaluation performance of the DVB-T2 in order to address the improvement of DVB-T2 compared with DVB-T in a single frequency network (SFN) transmission for receiving signals having the same data rate. These simulation results are obtained from the CSP DVB-T2 platform by using a model of an SFN network transmission based on two, three and four antennas. The obtained results with our considered configuration show clearly that in the case of two, three or four transmission antennas, the performance of SNR is average increased about 10 dB compared to DVB-T with the same data rate. This improvement allows to reduce the transmission power compared to DVB-T transmission or to increase the coverage of the receive area of an SFN network.

In single frequency network (SFN), there exist some special long delay spread channels as well as conventional multi-path channels. For pilot-aided orthogonal frequency division multiplex (OFDM) systems, channel estimation is usually accomplished by interpolation with pilots. However, few pilot subcarriers exist within coherent bandwidth under the long delay spread channels in SFN. In this case, conventional interpolation methods cannot work properly. This paper proposes a sine-wave based frequency domain interpolation method for channel estimation of pilot-aided OFDM systems in SFN. As simulation results show, the proposed method gives accurate channel estimation under the long delay spread channels, whereas the mismatched Wiener interpolation filter (WIF) estimates channel response inaccurately. Moreover, the proposed method performs well under conventional multi-path channels, especially for systems which adopt high order modulations.

In OFDM based Single Frequency Networks (SFNs) such as Digital Audio Broadcasting (DAB) and Digital Video Broadcasting (DVB), the mobile receiver is provided by the same signal from several synchronous transmitters at the same carrier frequency. This transmitter diversity structure makes SFNs very efficient in fading channels with an excellent spectrum saving, and very good power utilization over the service area. However, depending on the position of the mobile within the service area, these signals arrive with different delays causing possible echoes at the receiver. These echoes contribute to both the useful and the interfering parts of the signal. As the average received power in radio channels is a stochastic process, such contribution creates correlation between the different components of the Signal-to-Interference Ratio (SIR). In broadcasting practice, correlation was not taken into account when estimating the distribution of the SIR and the local coverage probability. This paper considers the effect of correlation on the estimation of the SIR and the coverage probability in OFDM based SFNs. Analyses are provided to show that in some situations the estimation error can be considerable when neglecting this correlation. To obtain a better estimation, the correlation coefficient between the total useful and total interfering parts of the received signal is first evaluated and then used as a correction factor in estimating the mean and standard deviation of the SIR. The obtained results show that such method can significantly reduce the estimation error of local coverage probability without increasing the computation complexity.