EFFICIENT IMPLEMENTATION OF FPGA-BASED FORWARD ERROR CORRECTING COMBINATION AND BIT TO CELL WORD DE-MULTIPLEXER FOR A SECOND GENERATION DIGITAL TERRESTRIAL TELEVISION BROADCASTING SYSTEM

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency division multiplexing is extensively used in modern digital television terrestrial broadcasting systems to support high performance bandwidth-efficient multimedia services. Accurate channel estimation is important for the application of simple channel equalization for the broadband multi-carrier orthogonal frequency division multiplexing systems and the accuracy of the channel estimation is crucial to the performance of the overall orthogonal frequency division multiplexing system in terms of the symbol error rate. In this paper, a robust channel estimation scheme is proposed for the receiver of the time domain synchronous orthogonal frequency division multiplexing based Chinese digital television terrestrial broadcasting systems. Simulations under different channel situations show that the proposed channel estimation scheme can also effectively solve the phase noise problem existing at the receiver and verify the efficiency of the proposed scheme.

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency division multiplexing (OFDM) is extensively used in modern digital television terrestrial broadcasting (DTTB) systems, such as the OFDM based Digital Video Broadcasting for Handheld (DVB-H) system, to support high performance bandwidth-efficient multimedia services. OFDM based DVB-H system is very sensitive to the nonlinear distortion at the transmitter and the carrier frequency offset at the receiver. The objective of this paper is to research and analyze the performance of the OFDM based DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel. A closed form of symbol error probability is derived for the OFDM based DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel. Theoretical results show closely matching with those obtained by simulations for the OFDM based DVB-H system in the presence of carrier frequency offset and nonlinear distortion under multipath fading channel.

Spectrum sensing for the China digital television terrestrial broadcasting system is considered in this paper. The spectrum sensing algorithms utilize PN sequences embedded in the frame headers to perform spectrum sensing. A theoretical lower bound on the misdetection probability for each spectrum sensor presented in this paper is derived. The performances of the proposed spectrum sensing algorithms are demonstrated by computer simulation for the multipath Rayleigh fading and steady state multipath Rayleigh fading channels. Simulation results show that the misdetection probability evaluated by computer simulations is close to the lower bound on the misdetection probability for a steady state multipath Rayleigh channel. When the probability of false alarm is 0.01 and a 50 ms of sensing time is used, a misdetection probability equal to 0.1 is achieved when the signal to noise power ratio is -16 dB, -18.8 dB, and -18 dB for modes 1, 2, and 3 in the multipath Rayleigh fading channel, respectively.

This paper relates to the application method of channel state information (CSI) to the Viterbi (maximum likelihood) decoder in the digital terrestrial television broadcasting system. The proposed Viterbi decoder uses the CSI derived from the pilots inserted in the transmitter of the COFDM (coded orthogonal frequency division multiplexing) system. The CSI is calculated by interpolation using the pilots in the receiver. The active real (I) and imaginary (Q) data after equalization are transferred to the branch metric calculation block that decides the euclidean distance for soft decision decoding and also the estimated CSI values are transferred to the same block. After calculating the euclidean distance for the soft decision decoding, the euclidean distance of the branch metric is multiplied by CSI. To do so, new branch metric values that consider each carrier state information are obtained. We simulated this method in Rayleigh fading defined in the ETSI standard. From the simulation, this method has better performance of about 0.15 dB to 0.7 dB and 2.2 dB to 2.9 dB in the Rayleigh channel than that of conventional soft decision Viterbi decoding with or without a bit interleaver where the constellation is QPSK, l6-QAM and 64-QAM.

Orthogonal frequency division multiplex-single frequency network (OFDM-SFN) has been widely used in the digital audio broadcasting system (DAB) and the terrestrial digital video broadcasting system (DVB-T) as a scheme of downlink broadcasting service. A novel system structure of single frequency cellular network (SFCN) is proposed by applying OFDM-SFN to conventional cellular systems. Transmitter macrodiversity and receiver selective diversity are adopted in the downlink and the uplink respectively. Theoretical analysis and numerical simulation in comparison with conventional cellular systems demonstrate the performance improvement of the proposed system.

Terrestrial digital multimedia TV/handle broadcasting (DMB-TH) is a newly upcoming framing structure, channel coding and modulation for digital television terrestrial broadcasting system standard of China, which is recently drafted and is ready to be verified in order to deploy mobile multimedia broadcasting services for the public. The adoption of strong channel coding techniques appears to be of key importance for mobile operators and broadcasters. Low-density parity-check (LDPC) codes have been widely considered as error-correcting codes for next generation communication systems. A good LDPC decoder design requires both implementation friendly LDPC codes and efficient decoder architectures. The quality of LDPC code is crucial in determining the coding gain and implementation complexity of LDPC hardware decoders. This paper presents a turbo-decoding message-passing algorithm (TDMP) based LDPC code search algorithm with hardware considerations. The main advantages of the proposed algorithm over the DMB-TH standard decoding algorithm are 1) improvement in coding gain by an order of magnitude at high signal-to-noise ratio (SNR), 2) reduced decoder complexity. The performance of the proposed TDMP architecture is shown by the comparison of simulation results.

Channel Estimation for the Multiple-antenna Chinese Digital Television Terrestrial Broadcasting Systems

Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) is appealing for the provision of high spectral efficiency in digital terrestrial broadcast systems. To fully obtain its advantageous features, it is very important to remove the frequency mismatch between the transmitter and the receiver. In this paper, we present the performance analysis of joint estimation of carrier and sampling frequency offsets in the MIMO-OFDM-based advanced television systems committee (ATSC) 3.0 system. In the MIMO-OFDM ATSC system, the continual pilot (CP) is primarily utilized to perform frequency synchronization. To efficiently suppress an unwanted bias introduced by the presence of random-likely located CPs, an optimal pilot subset is selected to form the basis of least squares frequency-offset estimation. A closed-form mean squared error is derived in the context of MIMO-OFDM, considering the multipath fading channel. We show via computer simulations and numerical analysis that the proposed estimation method achieves higher estimation accuracy than the existing estimation method.

A public process has been in place in the United States for six years to establish an HDTV terrestrial broadcasting standard. The process, having moved through a planning phase, a competition phase, and an examination phase, has now entered a cooperation phase. Remarkable progress has been made/spl minus/a testament to the process. During 1994 the American digital HDTV terrestrial broadcasting system will be tested, fully documented, and recommended to the FCC for adoption.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The transmitting aerials for terrestrial digital audio broadcasting (DAB) systems should have a low directivity in the horizontal plane. So, for example, the aerial of the central transmitter of a terrestrial single frequency network usually has a circular radiation pattern. The present report discusses the design features and advantages of using cylindrical strip radiators as elements of aerials in single frequency networks.

Pseudo-noise (PN) sequence is widely used in wireless transmission systems for synchronization, which is usually performed via cross-correlation, i.e. PN correlator, between the received signal and a locally generated PN sequence. However, the hardware implementation of such a correlator becomes the inhibiting bottleneck of integration due to the long tapped-delay line, particularly in the case of oversampling systems. Furthermore, few attempts have been made to improve the structure until now attributing to the random but simple coefficients of the PN correlator. This paper proposes a novel grouping and segmentation structure for filters with simple coefficients, such as a PN correlator. Remarkable hardware reduction has been achieved by multiplexing tapped-delay line and further operations skillfully. The arithmetic complexities of the conventional direct form structure and the proposed structure are compared based on a digital terrestrial multimedia broadcasting (DTMB) system. The advantages of the proposed structure are demonstrated by the FPGA implementation results.

We have been conducting research on an advanced digital terrestrial TV broadcasting system(advanced ISDB-T) that can transmit 4K/8K UHDTV content. The advanced ISDB-T has the segmented structure similar to ISDB-T. Therefore, advanced ISDB-T can provide both mobile reception service and fixed reception service using hierarchical transmission by frequency division multiplexing (FDM). Furthermore, the transmission capacity is increased by using a large-sized fast Fourier transform (FFT). Although large-sized FFT degrades speed tolerance in mobile reception, the advanced ISDB-T can mitigate this influence by selecting an appropriate scattered pilot (SP) pattern. In this paper, we analyze the influence of large-size FFT in mobile reception and evaluate the reception performance caused by differences in SP patterns through computer simulation and field experiments.

Japan Broadcasting Corporation (NHK) has been conducting research and development on large-capacity transmission technologies for next-generation digital terrestrial television broadcasting (DTTB) system. In this work, a transmission system inherited Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) has been developed, which can provide both fixed reception service and mobile reception service. The transmission system was developed with the aim of providing 4K/8K UHDTV broadcasting for fixed reception and HDTV broadcasting for mobile reception in one channel (6 MHz bandwidth). This report describes an overview of the transmission system for a next-generation DTTB called the advanced ISDB-T and its basic transmission performance.

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.

FPGA Implementation Of Dynamic Power, Area Optimized Reversible ALU For Various DSP Applications