Suhartono Tjondronegoro

Performance comparisons of adaptive MVDR and received LS beamforming on the downlink time varying channel of HAP system

We consider the performance comparisons of adaptive Minimum Variance Distortionless Response (MVDR) and received Least Squares (LS) beamforming on the downlink channel from High Altitude Platform (HAP) to high speed train. The channel, as modeled in CAPANINA project, is considered as time varying rician and flat fading process. Since the rician factor is moderate to high, adaptive MVDR beamforming is attractive in compensating for the rician fading channel. Due to the constraint in the cost function, MVDR beamforming neglects useful received signal particularly in the lower rician factors, hence, mismatch occurs. By implementing the LS beamforming, the receiver is able to adapt better to a more rayleigh fading channel case. The comparisons of the considered beamforming algorithms are given in terms of Mean Square Error (MSE) of beamforming weight tracking and Bit Error Rate (BER).

Application of a Mobile Telemedicine System with Multi Communication Links for Disaster Reliefs in Indonesia

Natural disasters sometimes occur at locations where medical facilities are not available. Although if such kind of a facility is near, the level of damage can over load this facility and require assistance of a more mobile resource. A mobile telemedicine system is considered an appropriate means catering for various catastrophic cases. This paper offers application of a mobile telemedicine system for disaster reliefs in Indonesia. The system consists of a low cost mobile telemedicine kit and a base unit. The main significant feature of this system is the facility of integrated health services which can be run during a normal situation or in disastrous cases. Furthermore, communication between these two units can be conducted via multicommunication links, so having choice of communication means become an advantage particularly for disaster relief.

Spectrum sensing of OFDM signals using GLRT detector with bootstrap approach

Among some of its duties, the cognitive radios main role is to do spectrum sensing in the surrounding radio environment. In order to do mapping and can determine the frequency of use vacant frequencies which can be optimized for the use of cognitive radio communication. Even to the worst conditions in which the detector system has no knowledge of the signal and noise. There are several techniques that can be used to perform spectrum sensing in this condition, among these techniques are simpler implementation of energy detection techniques. This technique has a weakness at noise conditions are unknown and uncertainty. In this condition, a technique that can be used and better than energy detection is GLRT detector. However, this detector requires choose threshold with empirically. This process has a problem when we move from one location to another, it is necessary to conduct empirical calculations again. And would face difficulties if we do detect a signal that is already active in a new place, so it is necessary to know the exact time the signal was not active. In this condition the bootstrap approach can help determine the threshold detector directly from the active signal is received. So the detector can gain threshold which is always updated with any condition, anytime and anywhere. The simulation result show that GLRT detector with bootstrap approach has a toughness in the face of uncertainty noise. Even able to exceed the performance of which is owned by the energy detector and GLRT. At condition SNR -5 dB and uncertainty noise 1 dB, GLRT with bootstrap approach improve probability of miss detection almost 0.030 than ordinary GLRT and 0.094 than energy detector.

Statistical properties proposed for blind classification OFDM modulation scheme

Classification of modulation scheme, previous step before demodulation, is the main part of an intelligent receiver at military or commercial application. Moreover, without definite parameters of the transmitted signal, blind modulation classification becomes a difficult task. Modulation classification becomes more challenging in real application with multicarrier modulation at fading channel. Furthermore, in recent years, the wireless communication has concerned to the orthogonal frequency division multiplexing (OFDM) because of spectral efficiency by using orthogonal multicarrier modulation. In this paper, we provided statistical characteristics of different modulation schemes from the OFDM signal with multipath (Rayleigh) fading channel. Based on standard of IEEE 802.16e, there are three possible modulation schemes used like a Quadrature Phase Shift Keying (QPSK), 16-QAM (Quadrature Amplitude Modulation), and 64-QAM. We analyzed those three modulation schemes by using statistical properties, such as, mean, variance, skewness, kurtosis and moment order.

Development of a new Biomedical Engineering Education Program at Institut Teknologi Bandung

Biomedical Engineering is the application of engineering principles and design concepts to medicine and biology, this field seeks to close the gap between engineering and medicine, in order to improve healthcare diagnosis, monitoring and therapy. At Institut Teknologi Bandung (ITB), the Biomedical Engineering (BME) undergraduate program has been conducted since 1998, as an option within the Electrical Engineering (EE) undergraduate program. In March 2013, the Institut Teknologi Bandung obtained a mandate from the Directorate of Higher Education - Ministry of National Education to offer a Bachelor Program in Biomedical Engineering. Therefore, we have to develop a new Biomedical Engineering Education Program (including its curriculum), based on many years experiences in running the existing undergraduate biomedical engineering program. This paper presents the development of a new 2013 Biomedical Engineering Curriculum for the undergraduate level at ITB. The program strength of basic sciences and engineering will allow the graduate students to understand rapidly new Biomedical Engineering and Technologies.

Sum rate capacity of multiuser MISO designed for HAPS high speed train application

The capacity gain proportional to the number of transmit or receive antenna promised by MIMO, has attracted many interests to implement MIMO on existing terrestrial and satellite system. A complementary to those existing systems is known as HAPS, and is situated in the stratosphere around 17–22 km. One of the interesting applications of HAPS is broadband transmission to high speed trains.

Precoding matrices for wireless MIMO communication system

To support providing broadband wireless communication services against limited and expensive frequency bandwidth issues, we have to develop a bandwidth efficient system. Therefore, this paper proposes a closed-loop MIMO (Multiple-Input-Multiple-Output) system using pre-coding matrices to optimize capacity and to increase system performance. The grand scenario of this concept is the attained advantages of the pre-coding matrices, which is guaranteed by its derived analysis. First, transformation matrix can allocate transmitted signals power suit to the channel. Second, it can be manipulated in order to maximize the minimum-distance at the receiver. Finally, this pre-coding matrix can mitigate inter-channel correlation. Furthermore, computer simulations validates that our system at 0 dB SNR (Signal to Noise Ratio) can reach optimal capacity up to 1 bps/Hz and error rate up to 0, 1 higher than opened-loop MIMO.

Segmental sinusoidal model for speech coding

Speech signal could be represented as a combination of sinusoidal signal with infinite combination of amplitude, frequency and phase. On quantization based on peak to peak, speech signal is detected its peaks, both of positive and negative. Then time distance between peak to peak would be quantized. In this paper, we explain a new method to quantize the speech signal which is segmented into peak to peak based on sinusoidal modeling. The part of signal between positive peak and following negative peak or vice versa is estimated as a half period of sinusoidal signal. Magnitude between peaks is the double of the ed sine amplitude. The experiment result showed that synthesis signal quality is reduced on the high frequency interval. Human perception due to the synthesis signal is good enough, because of less sensitivity human perception above 1 kHz.