Tetsuomi Ikeda

Performance evaluation of transmission system for 8K Super Hi-Vision satellite broadcasting

We developed a new transmission system for 8K Super Hi-Vision satellite broadcasting in Japan. This system has a transmission capacity of over 100 Mbps in a single 34.5MHz satellite transponder. The key technical feature of the new system are lowering roll-off factor to 0.03 and using 16APSK and LDPC code with a coding rate of 7/9. To confirm the transmission performance in a satellite channel, we conducted indoor transmission tests and transmission tests using Japanese communication and broadcasting satellites. This paper shows the transmission performance of this system and similar performance was obtained in indoor-transmission and satellite-transmission tests.

Development of MMSE Macro-Diversity Receiver with Delay Difference Correction Technique

We have been developing a minimum mean square error macro-diversity (MMSE-MD) reception system using distributed remote antennas and radio-on-fiber (RoF) links for use in live broadcasts of road races. For the system to be feasible, we have to consider the propagation delay differences among diversity branches due to RoF links and radio propagation. This paper describes a hardware implementation of an MMSE-MD receiver embodying our delay difference correction (DDC) technique and indoor and outdoor performance evaluations. Our prototype receiver perfectly corrected the propagation delay difference among diversity branches in less than 11 symbols duration in a time-varying multipath fading environment, and it was capable of the MD reception without outage on an actual road race course.

Evaluation of millimeter-wave MIMO-OFDM transmission performance in a TV studio

The authors have been developing a wireless HDTV camera for TV studio use, which can transmit high picture-quality HDTV signals with short delay. A MIMO-OFDM transmission system that has two transmitting and four receiving antennas in the 55 GHz-band was proposed to ensure a reliable link and was named the millimeter-wave mobile camera. Transmission experiments were conducted using a prototype system in a 150 m2-class studio and an anechoic chamber, where BER performance and MIMO channel characteristics were measured and compared. The results showed that BER performance depends on the received CNR and channel correlation. Computer simulation confirmed this relationship. Correct optimization of antenna positions can allow the received CNR and channel correlation distributions to be controlled in a LOS environment.

Performance evaluation of iterative LDPC-coded MIMO OFDM system with time interleaving in mobile line-of-sight environments

Iterative low-density parity-check (LDPC) coded multiple-input multiple-output (MIMO) systems are known to be able to theoretically achieve excellent performance by computer simulation. If the systems can exploit time interleaving long enough to cover a fading cycle, excellent error rate performance should be obtained in mobile line-of-sight (LOS) environments. This paper describes an iterative LDPC minimum mean square error with soft interference cancellation (LDPC-MMSE-SIC) receiver with a time de-interleaver before the MMSE detector and evaluates it using channel state information (CSI) acquired in outdoor measurements. We show that the iterative receiver with time interleaving improves the error rate performance significantly in mobile LOS environments and outperforms an LDPC maximum likelihood detection (LDPC-MLD) receiver with the same error correction and interleaving.

Practical delay difference correction in distributed MIMO OFDM systems

We developed a practical delay difference correction (DDC) technique and confirmed that it could perfectly compensate for large delay differences due to the RoF link. Furthermore, we showed by a computer simulation of road race relay broadcasting that D-MIMO with DDC can achieve better coverage performance than C-MIMO due to low spatial correlation and good average received CNR.

Performance of a 2×2 STTC-MIMO-OFDM in 800-MHz-band urban mobile environment

A 64-state 16-QAM space-time trellis code (STTC), which uses two transmitting antennas, is proposed and applied to a 2×2 MIMO-OFDM system for outdoor mobile transmission in the 800-MHz band. Although STTCs have been analyzed theoretically and the error performances have been simulated by many researchers, experimental results have rarely been reported. Therefore, we evaluated the performance of our 2×2 STTC-MIMO-OFDM in both a simulation and experiment in the 800-MHz-band urban mobile environment. As a result, excellent bit error rate (BER) performance obtained in the simulation was verified by the experiment.

Hardware Implementation of Proposed Antenna Selection Algorithm and Its Performance Evaluation Using Received Signals in Field Experiment

Multiple-input multiple-output (MIMO) systems with antenna selection are practical ones that can intuitively alleviate the computational complexity at the receiver and achieve good reception performance. Channel correlation, not just carrier-to-noise ratio (CNR), has a great impact on the reception performance in MIMO channels. We propose a simple antenna selection algorithm that exploits the condition number of the channel matrix and a predetermined threshold CNR. This paper describes the hardware implementation of the proposed algorithm and its performance evaluation, which was conducted in an indoor measurement using received signals obtained in the actual mobile outdoor experiment. The results confirm that our proposed method provides good bit error rate performance by setting a threshold CNR properly.

Development and Performance Evaluation of MMSE MacroDiversity Reception System With Delay Difference Correction

We have been developing a minimum-mean-square-error macrodiversity (MMSE-MD) reception system using distributed remote antennas and radio-on-fiber (RoF) links for use in live broadcasts of road races. The system selects remote antennas with good signal quality and combines their signals based on the MMSE algorithm to combat both small-scale and large-scale fading. For the system to be feasible, we have to consider propagation delay differences among diversity branches due to the RoF links and radio propagation. This paper describes a practical delay difference correction (DDC) technique that can keep signal continuity in any situation, the hardware implementation of an MMSE-MD receiver embodying the technique, and indoor and outdoor performance evaluations. Our prototype receiver perfectly corrected the propagation delay differences among diversity branches without losing signal continuity and maintained MD reception without signal outage across a wide area on an actual road-race course.