Lecture

• Fluctuation and Delay Spread of Coupling Loop Interference
  Tomoaki TAKEUCHI,Koichiro IMAMURA,Hiroyuki HAMAZUMI and Kazuhiko SHIBUYA↓summary

  summary

  Coupling loop interference(CLI)between transmitting and receiving antennas must be suppressed to achieve on-air relay in a single frequency network(SFN)for digital terrestrial broadcasting.To avoid this interference,we have developed and demonstrated the effectiveness of a CLI canceller.An important step toward to designing and installing an on-air relay station in an SFN is to measure and analyze the propagation characteristics of CLI.This paper describes the measured and analytical results of the delay spread,magnitude,and fluctuation of CLI.

• Development of Adaptive Array for ISDB-TAn Application of MMSE Adaptive Array to Broadcast-Wave Relay
  Tomoaki TAKEUCHI,Satoshi KIMURA,Hiroyuki HAMAZUMI and Kazuhiko SHIBUYA↓summary

  summary

  The transmission signal quality becomes degraded during relays of digital terrestrial broadcasting signals and must be improved at the relay station.In particular,we must give special consideration to co-channel interference because the relay station is usually located at a place that has a high probability of receiving un-desired broadcast waves.This paper describes a co-channel interference canceller which uses the minimum mean square error(MMSE)adaptive array at a digital broadcast wave relay station.In the proposed scheme,a scattered pilot is used as a reference signal to minimize the error which is defined as the difference between a known symbol and the combined one.The received data symbols are combined in each subcarrier on the basis of interpolated optimal weights,thus canceling the interference.Numerical examples and indoor experimental results are presented in this paper to verify the effectiveness of the proposed scheme.

• Maximum Likelihood Decision-Directed Adaptive Array Based on Combine, Compare and Select Operation in Broadcast Wave Relay Stations for ISDB-T
  Tomoaki TAKEUCHI,Yoshikazu NARIKIYO,Kazunori YOKOHATA,Koichiro IMAMURA, Hiroyuki HAMAZUMI and Kazuhiko SHIBUYA↓summary

  summary

  We are developing a minimum mean square error(MMSE)adaptive array as a countermeasure against co-channel interference at digital broadcast relay stations.However,the conventional algorithm which uses a scattered pilot as a reference signal has a problem with interference from other ISDB-T signals.This paper proposes a combine,compare,and select operation maximum likelihood decision-directed weight control algorithm.Numerical examples and field experimental results performed using a prototype verified the effectiveness of the method and the possibility of using a decision directed adaptive array at a digital broadcast relay station.