Mobile Location Finding Using ATSC Mobile/Handheld Digital TV RF Watermark Signals
ABSTRACT This paper investigates the use of ATSC M/H digital television (DTV) signal for location finding. In comparison to satellite based location finding system, DTV signals have higher field strength, wider bandwidth, lower frequency band, and DTV transmission towers are pervasively available everywhere. They can be used for indoor and mobile location finding in major cities where satellite based system might not function well. The ATSC receiver can obtain the multiple transmitter impulse responses and signal arrival times using the embedded RF watermark (RFWM) signal, and then derives its geographic coordinates based on the position of ATSC transmitters. As a critical step of this process, the transmitter identification in mobile environment has significant impact on the overall accuracy of location finding. In this paper, we present extensive analytical and simulation results to demonstrate the performance of RFWM technology over mobile channels.
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ABSTRACT: A transmitter identification system for DTV distributed transmission network using embedded pseudo random sequences is investigated. Different orthogonal pseudo random sequences and their suitability for transmitter identification are discussed. Code generators are developed to study the auto-correlation and cross-correlation properties of the Kasami sequences. To speed up the identification process, the embedded pseudo random sequence is preferred to be time-synchronized with the DTV frame structure. Therefore, the length of the identification code has to be truncated before it is fitted into each field of the ATSC DTV signal. The impact of truncation noise and in-band DTV interference on transmitter identification is also investigated. It is shown that the auto-correlation and cross-correlation properties are only slightly affected by truncation. It is also found that the dominant interference to the transmitter identification is the in-band DTV signal. The signal to truncation noise ratio and signal to DTV interference ratio in the correlation output are derived, and verified via simulation. It is further recognized that in-band DTV interference can only be mitigated by increasing the code length or by time-domain averaging technique to smoothen out the in-band interference.IEEE Transactions on Broadcasting 10/2004; · 2.65 Impact Factor
Article: Single frequency networks in DTV[Show abstract] [Hide abstract]
ABSTRACT: Single Frequency Networks (SFNs) offer many advantages including better coverage, less interference, less power, and higher reliability. SFNs can also free up extra TV channels, resulting in more efficient use of the spectrum. The paper presents an overview of the advantages of SFNs and some basics about how to implement them. The significantly improved Signal to Interference performance and less radiated power in SFNs are derived from simple propagation models. Some potential problems that must be considered are discussed, including limitations due to receiver performance. Several simple formulas that should be helpful in quickly estimating and evaluating an SFN system are also presented. Finally, the likely implications of SFNs are covered, in particular the need for changed FCC rules and increased competition through a higher frequency reuse. The idea of the FCCs only limiting the power outside of the service area and letting the broadcasters decide on transmitter locations, number of transmitters and power levels is proposed.IEEE Transactions on Broadcasting 01/2006; · 2.65 Impact Factor
Conference Paper: A new position location system using ATSC TxID signals[Show abstract] [Hide abstract]
ABSTRACT: A new position location technique using the transmitter identification (TxID) sequences in the digital TV (DTV) signals is proposed in this paper. Conventional Global Positioning System (GPS) usually does not work well inside buildings due to the high frequency and weak field strength of the signal. In contrast to the GPS, the DTV signals are received from transmitters at relatively short distance, while the broadcast transmitters operate at levels up to the megawatts ERP. Also the RF frequency of the DTV signal is much lower than the GPS, which makes it easier for the signal to penetrate buildings and other objects. In this paper, the proposed position location system based on DTV TxID signal is presented. Performance of the proposed technique is evaluated and compared with other existing position location systems. Possible ways to improve the accuracy of the new position location system is discussed.Vehicular Technology Conference, 2005. VTC 2005-Spring. 2005 IEEE 61st, Stockholm, Sweden; 05/2005