TDoA Positioning in Single Frequency Networks without Transmitter Identities

The conventional global positioning system (GPS) can often fail to provide position determination for a mobile user in indoor and urban environments. To cope with GPS failure in such environments, a new navigation system which utilizes a terrestrial digital multimedia broadcasting (T-DMB) signal to obtain the mobile user's position is presented. Since the T-DMB transmitters in Korea construct a single frequency network (SFN), which forces the transmitters to be synchronized, the mobile user can measure a time difference of arrival (TDOA) for all audible T-DMB transmitter pairs. The time difference between T-DMB transmitters is converted to a distance difference by multiplying the time difference by the speed of light. Using these measurements and a TDOA positioning method, the mobile user position can be estimated. An experiment with a T-DMB receiver and a data acquisition (DAQ) board is performed in Seoul to analyze the error characteristic of TDOA measurements. It is certified that the measurement error is bounded under 300 m and can be used to determine the mobile user's position with a small standard deviation.

The location technology based on time difference of arrival (TDOA) is one of the key technologies in The 3rd Generation Telecommunication. In this paper, TDOA positioning method based on modified Chan algorithm for CDMA2000 mobile network is proposed. Pilot delay measurement is adopted to realize TDOA positioning parameter detection. A mathematical model of TDOA positioning is established and the location solving method under ideal Gauss circumstance is put forward. In accordance with the trait of Non Light of Sight (NLOS) propagation delay obeying index distribution in the mobile communication environment, NLOS estimation covariance correction method is presented to decrease the NLOS influence upon positioning accuracy. Theoretical analysis and simulation results show that the positioning method in discussion is possessed with good qualities of positioning in actual channel environment. Meanwhile, with the low computational complexity, the proposed algorithm is well applied to mobile location of CDMA2000 telecommunication systems.

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.

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.

There are several methods available for the positioning of mobile devices, such as GNSS, Wi-Fi, Bluetooth and radio access technology (RAT) dependent methods. Among them, the RAT-dependent positioning method uses only measurement information from the mobile network so that devices do not need to be equipped with receivers for GNSS, Wi-Fi or other systems. This can lead to device simplification and power savings. In this paper, we consider the time difference of arrival (TDOA) positioning method, which is a typical RAT-dependent positioning method. The positioning accuracy of the TDOA positioning method depends on which 4 base stations (BSs) are selected. For mobile network TDOA positioning, one method is to select BSs near the mobile device. However, if two or more BSs of the selected 4 BSs are near each other, the positioning accuracy is reduced. Another BS selection method is to select BSs so that the tetrahedron volume determined by connecting the positions of the 4 BSs is large. However, in this method, the BSs far from the mobile device are likely selected, so the elevation angles between all 4 selected BSs and the mobile device are small. In this case, the positioning accuracy is also low. Therefore, we propose a BS selection method in which at least one of the BSs has a large elevation angle while maximizing the volume of the tetrahedron formed with the positions of the 4 BSs, and evaluate the effectiveness of the proposed method in terms of positioning accuracy.

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.

This paper presents a comparative analysis of direction of arrival (DOA) estimation techniques for the application in a linear antenna array of a passive bistatic radar (PBR). State of the art and emerging DOA algorithms were investigated in order to identify techniques that achieve optimum accuracy performance. The viability is demonstrated with experimental data obtained from a field trial with a PBR that exploits illuminations by the digital transmissions standard DVB-T2. The trial focused on air surveillance in the controlled traffic region (CTR) of an international airport. A target localization scheme was developed, with special emphasis on accurate estimation of the aircraft height, were the multistatic nature of a single frequency network (SFN) is exploited. As a consequence, the PBR is able to receive and process multiple time difference of arrival (TDOA) measurements from a single target within the same signal. This in conjunction with the system's DOA capability allows to accurately estimate 3D positions of air targets within the CTR.

We have been conducting research on a transmission system using ultra-multilevel orthogonal frequency division multiplexing (OFDM) technology and dual-polarized multiple-input multiple-output (MIMO) technology based on the digital terrestrial broadcasting signal format, ISDB-T. As a technology of a single frequency network (SFN) for the next-generation of digital broadcasting, we studied a space time coding (STC) - space division multiplexing (SDM) transmission in which STC and dual-polarized MIMO-OFDM are used together. In this paper, we studied a scattered pilot (SP) scheme for the channel estimation in STC-SDM transmission and the coding schemes. Computer simulations confirmed the advantages of STC-SDM transmission compared with the conventional SFN scheme in environments in which the desired to undesired signal ratio (D/U) is low. We also show the results that STC-SDM transmission with space time block coding (STBC) and space frequency block coding (SFBC) has the same characteristics as transmissions under fixed reception conditions.

For digital terrestrial television broadcasting (DT-TB) systems, orthogonal frequency division multiplexing (OFDM) technique is considered to be an effective method to combat the frequency selective channel cause by multi-path effect. In the single frequency network (SFN) scenario, Alamouti space frequency block coding (SFBC) is introduced to provide spatial diversity gain and improve the link stability. However, both OFDM and Alamouti SFBC are sensitive to time-variant during mobile reception. In this paper, we propose a decision feedback equalization algorithm for inter-carrier interference (ICI) can-celation of the dual (PN) padded time domain synchronization OFDM (TDS-OFDM) DTTB system over doubly selective channel. Our algorithm is proven by numerical simulations which show bit error rate (BER) gain over mobile SFN channel and can be adopted in mobile high density television (HDTV) transmission systems.

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.

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%.

During the last decade, several land mobile communication networks have been developed based on full satellite solutions such as Globalstar or Iridium systems or on huge terrestrial networks such as GSM for example. Deploying new terrestrial networks or new satellite constellations for new telecommunication or broadcast mobile systems on very large areas would be so expensive that another solution is now often considered: hybrid systems with a terrestrial segment to cover high‐density built‐up areas and a satellite segment to bring services to the largest part of coverage area. In the framework of Satellite Digital Multimedia Broadcasting CNES project, such a hybrid mobile broadcast system was studied, in particular air interface performances. This performance assessment required a good knowledge of the hybrid single frequency network (SFN) propagation channel including a geostationary satellite and terrestrial gap fillers. The requirement for an exhaustive characterization of the hybrid SFN propagation channel involved the development of a specific channel sounding solution. Moreover, mobile telecommunication systems recently developed use spatial diversity techniques to take benefit from multipath spatial decorrelation in particular. The measurement of diversity gains in actual conditions can provide information very helpful for network deployment and air interface design. The CNES channel sounder enables to carry out such diversity measurements using only propagation data. This paper presents this channel sounder developed and used to measure the SFN radio propagation channel with four transmitters in spatial diversity configuration. Copyright © 2009 John Wiley & Sons, Ltd.

This paper proposed an approach based on genetic algorithm (GA) to deploy green single frequency network (SFN) for digital terrestrial television multimedia broadcasting (DTMB). The network optimization goal is to achieve energy efficiency, low cost, low carbon and low exposure to radiation, which caters to the sustainable development strategy. The method is applied over a real area of China, which is described by a digital terrain model (DTM) with the resolution of 20m. In order to show the validity of green deployment, optimization results of three other planning strategies are also presented. Comparisons between optimization results of the four planning strategies show that green deployment strategy can achieve energy consumption savings and low exposure to radiation. Energy consumption savings lead to CO2 reductions and cost savings.