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To increase the spectral efficiency of HFC network, the standard of digital video broadcasting for cable systems (DVB-C2) was completed in 2010 and products that support the DVB-C2 is expected to be released within years. Before making products for DVB-C2 receiver, the performance of them should be investigated under various channel conditions first. Thus, we show the performance of the proposed structure for a pre-FEC in DVB-C2 receiver considering the channel model including additive white Gaussian noise (AWGN), a frequency offset, and echo channels to provide information about the implementation of DVB-C2 receiver. Based on the simulation results, we implement the pre-FEC using two field programmable gate arrays (FPGAs) and show the measured symbol error rate (SER) between the transmitted and received quadrature amplitude modulation (QAM) symbols with respect to various symbol timing estimations (STEs) of synchronization (SYNC) and powers of analog-to-digital converter (ADC) input. Because the STE makes the received pilot symbols in preamble rotated and these rotated pilot symbols are used in channel estimation, it affects the channel estimation and SER of pre-FEC. In addition, the channel estimation impaired by the STE causes the received QAM symbols to have biased mean values compared with the transmitted 4096QAM symbols. Since this degrades the performance of pre-FEC, the automatic gain control (AGC) is added after zero-forcing linear equalizer (ZF-LE) to improve the performance of pre-FEC. As the power of ADC input decreases, the SER increases due to the noise enhancement of ZF-LE.

A receiver of upstream cable modem (CM) for data over cable service interface specifications (DOCSIS) 3.0 is proposed and implemented in field programmable gate arrays (FPGAs). The receiver, which can demodulate four upstream channels simultaneously, consists of a digital down converter (DDC), a pre-forward error correction (FEC) and a FEC decoder. In DDC, fixed decimation and variable decimation with respect to symbol rate are used to remove adjacent channel images. An automatic gain control (AGC) uses a power calculation in a packet detection (PD) to reduce hardware complexity. Coefficients of symbol timing estimation (STE) use the sign of preamble symbols for eliminating multipliers. In addition, STE operates only for some parts of preamble to save power consumption. We simulate estimated AGC values, success probability of STE, estimated frequency offsets. In addition, it is found that when the bit error rate (BER) of the pre-FEC of 64QAM is 10-5, the required Eb/N0 is 19.5 dB under the conditions of additive white Gaussian noise (AWGN), a frequency offset, and echo channel. We measure the spectrum of DDC output, an estimated AGC value, and an estimated frequency offset, and experiment on FEC decoder. Measured results show the maximum transmitted error vector magnitude (EVM) of 1.54 % and the maximum received EVM of 2.67%.

This paper presents a new economic and effective TPEG (transport protocol experts group) application for location based service (LBS) that can be provided in terrestrial-digital multimedia broadcasting (T-DMB) transmission system. We propose a novel point-of-interest (POI) application interoperable with TPEG protocol, and introduce the POI data server/client and the DMB receiver with TPEG decoder implemented by using the proposed protocol. The stability and effectiveness of the proposed protocol is verified through the experimental broadcasting, and the pilot service using the commercial T-DMB network is being provided successfully