Mitsuhiro Tomita

New video synthesis based on flocking behavior simulation

In this paper we present the combination of two well known techniques like video synthesis and flocking behavior to introduce a new form of video animation, real-video based animation. This system can be used in the elaboration of games and special effects for movies. We have developed a system that makes possible to manipulate objects in the frames of a video while maintaining its natural appearance and complexity and allows us to multiply an object in the frame or control the pattern of its movement. The system accepts as input a video in format AVI and renders automatically another with new patterns from the original. Video synthesis and flocking behavior are well known independent techniques but the combination of them was not researched yet.

A multi-user CDMA receiver utilizing decorrelating detector with additional dummy pilot response

A pilot assisted CDMA system which uses extended spreading sequences with guard sequences under a quasi-synchronous condition is capable of separating the interference components included in the input of a de-correlating receiver by solving a system of linear equations. The performance of such a system, however, depends on the property of the de-correlating matrix consisting of the received pilots, which correspond to the respective user spreading sequences and the multi-path channel conditions. That is, the regularity of the matrix often tends to degrade, and the rank reduces occasionally primarily due to the multi-paths, resulting in solutions that are vulnerable to AWGN. The present paper proposes an effective technique to solve this problem by introducing a virtual user into a group of real users that are to be served. The simulation results indicate a remarkable improvement in the bit-error-rate (BER) performance. In addition, based on the BER performance, the system has a RAKE-like function that has power-sum characteristics. Copyright

Error rate performance improvement for a decorrelating CDMA receiver by introducing additional dummy pilot response

A pilot assisted CDMA system which uses extended spreading sequences with guard sequences under a quasi-synchronous condition is capable of separating the interference components included in the input of a decorrelating receiver by solving a system of linear equations. The performance of such a system, however, depends on the property of the de-correlating matrix made of the pilots responses. The regularity of the matrix often tends to degrade due to primarily the multipaths, resulting in the solutions vulnerable to AWGN. This paper proposes an effective technique to solve this problem by introducing a dummy pilot associated with a virtual user into a group of the real users to be served. The simulation indicates a remarkable improvement in the bit-error-rate performance. In addition, it proves a RAKE like function with power-sum-characteristics.

A multi-rate CDMA system with block-spreading schemes for anti-interference and high frequency efficiency

For mobile systems higher than 3G, multi-rate data service is becoming an important issue. This paper proposes a multi-rate block-spreading CDMA system as an efficient scheme which is capable of intra-cell-interference free operation and inter-cell-interference reduction by a factor of reciprocal of the spreading factor. With a use of an accurate pilot transmission scheme, it is shown that a high frequency utilization efficiency can be achieved for various mixed data rate services.

Performance of block spreading MIMO-CDMA systems for heavy multi-path environment

In CDMA systems using block spreading techniques, where a data-block modulates a spreading sequence to produce a transmitting symbol, a user inherent orthogonal carrier-frequency modulating system is proposed. This method contributes to accommodating as many users as the processing gain L and to reducing the guard sequence overhead. Applying a MIMO configuration without using coding and multiple constellation on PSK modulation to this system, especially using N pieces of receive antennas is considered. This block spreading system is capable of accommodating as many users per orthogonal carrier as N, by using a method of concatenating the N symbols received at N antennas. This means that the aggregate data rate per chip increases N in the maximum. Further it is shown that a fairly good error rate performance is achieved by selecting the practical aggregate data rate to be about 80% of the maximum rate.

Sequential detection CDMA multi‐user receiver

This paper proposes c1 sequential detection multi-user receiver which is constructed over a CDMA system such that a transmitter transmits a symbol made bv spreading the spectmm with an enveloped sequence prorected by guard sequences, and a receiver de-modulates the core-sequence part of the received symbol with a de-correlating detector or an MMSE detector and has an advantage of increasing the number of the active users. This sequential detection uses such a method that the best user signal is estimated out of the soft outputs, which are obtained by solving a de-correlating system of equations, and then detected, followed by removing the detected user component from the received symbol. All the user signals may be sequentially detected by repeating the method stated above. The computer simulution reveals a remarkable improvement in bit error rate performance compared to conventional systems.

Sequential detection CDMA multiuser receiver

This paper proposes c1 sequential detection multi-user receiver which is constructed over a CDMA system such that a transmitter transmits a symbol made bv spreading the spectmm with an enveloped sequence prorected by guard sequences, and a receiver de-modulates the core-sequence part of the received symbol with a de-correlating detector or an MMSE detector and has an advantage of increasing the number of the active users. This sequential detection uses such a method that the best user signal is estimated out of the soft outputs, which are obtained by solving a de-correlating system of equations, and then detected, followed by removing the detected user component from the received symbol. All the user signals may be sequentially detected by repeating the method stated above. The computer simulution reveals a remarkable improvement in bit error rate performance compared to conventional systems.

An interference canceling receiver with differential frames for high frequency usage CDMA systems

A new signal demodulation system for CDMA receivers is proposed. This system has an effective function of canceling the interference noise components in the received symbol frames. For a target symbol frame to be detected, the differential frames are produced, each of which is made by subtracting one of the neighboring symbol frames from the target frame. The interference noise being left in some of the differential frames is much less than that in the target frame. By demodulating only such noise cancelled differential frames that have been estimated with effective analyzing sequences, the information conveyed on the target frame with a heavy interference can be detected. The simulation indicates powerful canceling performance for all the possible interference disturbance is achieved.

An inter-frame demodulation system for CDMA receivers with heavy interference canceling function

A new signal demodulation system for CDMA receivers is proposed. This system has an effective function of canceling the interference noise components in the received symbol frames. For a target symbol frame to be detected, the differential frames are produced, each of which is made by subtracting one of the neighboring symbol frames from the target frame. The interference noise being left in some of the differential frames is much less than that in the target frame. By demodulating only such noise cancelled differential frames that have been estimated with an analyzing sequence, the information conveyed on the target frame with a heavy interference can be detected. The simulation indicates effective canceling performance for all the possible interference disturbance is achieved.

A narrowband multi-ary FSK transmission principle using sampling function waveform modulation

Conventional FSK uses shift frequencies of integer times the frame rate. If shift frequencies using non-integers (NIFSK) could be used, the frequency utilization efficiency would improve due to the capability of multi-ary transmission. However, since a framed sequence consisting of NIFSK includes abrupt transients, the waveform suffers from considerable distortion when it is transmitted via a bandlimited path. To solve this problem, we propose sampling function waveform modulation system (SAFWM). SAFWM uses a modified sampling function waveform that is immune to intersymbol interference generated in the process of conveying each sampled value of an FSK signal. The transmission bandwidth is only slightly larger than that of zero to the maximum shift frequency. At the receiver, the sampled values are restored by correlation detection with the same waveforms, and are transformed into the original FSK. To accurately restore a waveform of transmitted NIFSK signals, frame extension is introduced. Distortionless transmission performed with this method is confirmed by computer simulation. This principle can be applied not only for FSK/PSK but also for FSK-SS (spread spectrum) and FH-SS, resulting in improving their frequency utilization efficiencies.