Layered Division Multiplexing With Co-Located Multiple-Input Multiple-Output Schemes

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.

<p>Advanced Television Systems Committee (ATSC) 3.0, the new generation digital terrestrial television standard, has been designed for facing the new challenges of the future broadcasting systems. ATSC 3.0 has been built using the most recent cutting-edge technologies. Layered division multiplexing (LDM) is one of the major components of the new system baseline. LDM provides a tool to make flexible use of the spectrum for delivering simultaneous services to stationary and mobile services. This paper presents the performance evaluation of ATSC 3.0 core services in mobile scenarios using LDM. Simulation results are presented to analyze the influence of different LDM ensemble configuration modes for mobile reception. The simulation results have been also confirmed by laboratory tests under different channel models. The signal to noise ratio threshold values confirm the excellent behavior of ATSC 3.0 and LDM in mobile and portable scenarios.</p>

The Advanced Television System Committee (ATSC) is currently developing the next-generation U.S. Digital Terrestrial Television (DTT) standard, known as ATSC 3.0. Two disruptive technologies for the physical layer are being evaluated, Layer Division Multiplexing (LDM) and Time Frequency Slicing (TFS). LDM consist in the transmission of a signal composed of two independent signals (layers) which are superimposed together at different power levels. These two layer can be configured with the desired robustness and capacity. LDM enables the efficient provision of services addressed to mobile and fixed reception in a more efficient way than the classical Frequency Division Multiplexing (FDM) and Time Division Multiplexing (TDM) since full bandwidth and transmission time are used in both layers. However, practical operation is restricted due to several implementation constraints such as the use of common parameters and transmitter blocks for both layers (e.g. a common time interleaver). The use of TFS allows for an improved frequency diversity by the distribution of the service data across multiple Radio Frequency (RF) channels instead of using a single RF channel. The paper investigates the potential gains provided by the increased frequency diversity with TFS in conjunction with LDM.

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Advanced Television Systems Committee (ATSC) 3.0 standard does not support the combined structure of layered division multiplexing (LDM) and multiple-input multiple-output (MIMO). Recently, previous works have evaluated the theoretical performance of LDM plus MIMO structure for enhanced system capacity. However, the practical performance for the structure has not been investigated yet over the realistic channels. This paper presents the practical performance of the layered MIMO broadcasting system evaluated by a working prototype. To this end, the ATSC 3.0-centric prototype transmitter and receiver are implemented. Based on the real hardware solutions, the laboratory-measured transmission performance is analyzed with respect to the crosstalk power within the MIMO channel, i.e., cross-polarization discrimination (XPD).

In this paper, we present an efficient transmission method of multiple broadcasting services using layered division multiplexing (LDM) and scalable high efficiency video coding (SHVC) based on the next generation terrestrial digital broadcasting standard, advanced television systems committee 3.0. In a two-layer LDM system, each layer forms a physical layer pipe that carries base layer and enhancement layer video streams of SHVC, respectively. This combination of physical and presentation layers technologies can maximize channel utilization when multiple broadcasting services are delivered in a single radio frequency channel with different robustness and reception conditions. An intensive performance analysis is provided when the proposed combination of LDM and SHVC is compared with other approaches, such as time division multiplexing and/or high efficiency video coding simulcast broadcasting. Several performance measurements are also introduced, such as constant data rate measurement and constant quality measurement, which are used to evaluate the performance of video codecs in conjunction with different physical layer system parameters. A prototype hardware system with LDM and SHVC capable of selecting different parameter combinations is tested in the laboratory and in real field environments to verify the performance and feasibility of the proposed LDM and SHVC combination. Results show that the proposed LDM and SHVC combination provides significant gains on video service quality as well as reception robustness.

Recent broadcast standards support Layered Division Multiplexing (LDM) to achieve graceful degradation as signal quality degrades at the receiver. LDM is accomplished by using different constellations within the same Radio Frequency (RF) spectrum. LDM thus enables delivering multiple service tiers in a single broadcast channel. LDM when used in conjunction with scalable source coding codecs such as the Scalable extension of High Efficiency Video Coding (SHVC), further helps improve overall spectrum utilization and efficiency. In this paper we investigate a 2-tier broadcast LDM based service with one service tier aimed at lower video resolution such as 540p, 720p, 1080p for a mobile receiver (smaller/indoor antenna) and the other service tier targeting twice the video resolution of the lower tier, for stationary receivers (larger/outdoor antenna). The primary contribution of this paper is to identify 2-tier transmission configurations of interest to broadcasters and compare the spectrum and bitrate coding efficiency gains of an SHVC-based multi-tier service versus a simulcast (single layer) based multi-tier service for an Advanced Television Systems Committee (ATSC) 3.0 transmission system. Bitrate savings ranging from 38% and 57% is observed for the SHVC based layered system. For large coverage and pedestrian with a receiver test scenarios, channel utilization savings ranging from 23% to 46% is observed. For mobile and tablet in bedroom scenarios a smaller broadcast bandwidth savings ranging from 6% to 9% is observed.

Several previous studies have demonstrated that additional low-rate data can be transmitted in Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) systems by modulating the polarity of the transmitter identification (TxID) signal. Previously proposed additional-data transmission schemes can offer an additional reliable transmission channel, and thus they have a very large coverage area compared to that of a DTV signal. Unfortunately, as the cost of a reliable transmission, they have a limitation in their maximum data rate. In this paper, we propose a new additional data transmission scheme based on sequence phase modulation (SPM) to increase the data rate. The proposed scheme exploits not only the polarity but also the phase of a TxID signal, and thus it significantly enhances the data rate compared to conventional schemes.

In a single frequency network (SFN) for the Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, co-channel interference induced by the multiple transmitters and/or repeaters which use the same output channel is inevitable. Since the presence of interference results in the performance degradation of the SFN, it is crucial to manipulate the interference by adjusting the transmit power and the emission time of each transmitter and repeater within the SFN. In the ATSC terrestrial DTV system, in order to facilitate the interference manipulation process, a transmitter identification (TxID) signal which is embedded in the transmit signal from each transmitter and repeater is recommended. However, such an embedded signal may degrade the DTV signal quality even though the injection level of the TxID signal is very low compared to the DTV signal. Hence, the effect of the TxID signal on the DTV signal needs to be investigated before deploying the SFN with TxID signal. In this paper, the effect of the TxID signal on the performance of legacy DTV receivers is investigated not only with extensive computer simulation but also with laboratory and field tests. According to the various test results, the average performance loss of the conventional DTV receiver due to the TxID signal is less than 0.2 dB when the TxID signal is injected at 30 dB below the DTV signal power.

This paper proposes an improved additional data transmission (ADT) system based on low density parity check (LDPC) code which can transmit an additional data stream in the Advanced Television Systems Committee (ATSC) terrestrial digital television system. The LDPC code based ADT system can offer an additional data of rate up to a few megabits per second (Mbps) which is significantly increased compared to the conventional data transmission schemes used in the transmitter identification system.

The next generation digital TV (DTV) broadcast, namely Advanced Television System Committee (ATSC) 3.0, relies on substantial single frequency networks (SFN), each of which requires a studio to transmitter link (STL) to transmit data from the broadcast gateway (BG), leading to significant construction costs. Therefore, the wireless in-band distribution link (IDL) technology is proposed, which uses layered-division multiplexing (LDM) to transmit the STL data via wireless links from the BG to the SFN transmitters within the same spectrum as the broadcast services. In this paper, we propose the time synchronization and signal detection algorithm for wireless IDL systems with both unicast and broadcast signals. We introduce two multiplexing schemes, N-LDM and 3-LDM, and demonstrate their superiority over traditional frequency division multiplexing (FDM). To overcome the challenge of multi-access interference and synchronization errors caused by multipath, we develop a unique word (UW) design algorithm for transmitted signals and a double threshold correlation detection algorithm (DTCDA) that outperforms traditional ones. We employ a second threshold to enhance detection performance at low signal-to-noise ratios, and utilizes successive interference cancellation (SIC) to mitigate multiple-access interference. More importantly, our approach requires no knowledge of the unicast user number or channel state information. Simulation results validate the effectiveness of the proposed scheme.

In this paper, we present performance evaluation of multiple physical layer pipe (PLP) based layered division multiplexing (LDM) systems for the next generation terrestrial broadcasting. In addition to a conventional multiple-PLP configuration, which is based on time division multiplexing (TDM), a variety of LDM configurations, which includes combinations of TDM and two-layer LDM, and three-layer LDM, are considered. Given three different broadcasting contents are delivered by three PLPs, performance comparison and analysis are provided when four different multiple-PLP configurations including TDM, two-layer LDM, and three-layer LDM are used.

New digital television standards are emerging to meet the demand for new services from TV broadcasters, as well as to support new high-resolution audio and video formats available on the market. In Brazil, the Brazilian Digital TV System (SBTVD) Forum defines the standard to be adopted. Among the currently available physical layer technologies, the Advanced Television Systems Committee (ATSC) 3.0 standard offers great flexibility in operating modes, depending on the broadcasters’ requirements and propagation conditions, for both fixed and mobile reception. This allows the system to be configured to balance robustness and transmission efficiency. This paper presents the performance test results in various mobile reception scenarios in the city of Rio de Janeiro, using an ATSC 3.0 signal with a transmission rate of 32.3 Mbps in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 2$</tex-math> </inline-formula> Multiple-Input Multiple-Output (MIMO) configuration. The results showed a reception success rate of 53.6%, with an increase in reception errors for Carrier-to-Noise Ratio (C/N) lower than 26 dB. Furthermore, reception errors were detected with greater intensity when the received signal level was below -70 dBm. Although the overall success rate was around 50%, the complementary metrics (C/N threshold, RSSI, and PLP0 error behavior) were consistent with theoretical expectations, demonstrating that ATSC 3.0 performs effectively under real urban mobility conditions at high spectral efficiency. ATSC 3.0 thus proved effective in broadcast transmission, meeting the needs for ultra-high-definition (UHD) audio and video broadcasting.

This paper aims to identify and evaluate the protection ratios and overload thresholds between 700 MHz FDDLTE and analog/digital terrestrial television systems. The evaluated analog and digital terrestrial television (A TT and DTT respectively) systems were the NTSC-M and DTMB, respectively. All the tests were conducted in a confined environment at the laboratory level. Eight different interference scenarios were evaluated under different LTE configurations such as 0/100 % of system load and 5, 10, and 20 MHz of bandwidth. For each interference scenario and LTE system configuration, co-channel and adjacent channel interference conditions were evaluated with a frequency offset between the wanted and unwanted signal of up to 100 MHz. A total of 964 measurement values were registered during the laboratory tests. The tests intended to identify the conditions that make possible the coexistence between these services. The results analysis shows that the ATT service is at least 14 dB more sensible to LTE interference than the DTT service. The ATT service is at least 4 dB more sensible to LTE interference from the left side (-$\Delta f$) than from the right side ($+\Delta f$). The LTE user equipment is 9 dB more sensible to co-channel interference from the DTT service than from the ATT service. The LTE user equipment and base station are more sensible to adjacent channel ATT interference from the right side (+$\Delta f$) than from left side (-$\Delta f$) and from $\pm\Delta f$ of DTT interference.

In this paper, we propose an additional data transmission scheme for the ATSC (Advanced Television Systems Committee) terrestrial DTV (digital television) systems based on a low rate systematic irregular repeat-accumulate (SIRA) code. Unlike the previously proposed additional data transmission scheme using TxID (transmitter identification) signals, the proposed scheme conjuncted with a DTV VSB signal cancellation technique is suitable for high data transmission. Compared to the previous additional data transmission scheme based on a low rate systematic repeat-accumulate code, the BER performance of the proposed scheme is significantly improved. The additional data is encoded with a simplified IRA channel coding scheme and injected to the conventional VSB signals with the bury ratio (BR) of -27 dB. With the proposed scheme, an additional data of rate up to 1 Mbps can be transmitted along with the ATSC terrestrial DTV signals by minimizing the detrimental effects on the ATSC terrestrial DTV systems.