Youngsik Hur

Analysis of 60 GHz band indoor wireless channels with channel configurations

In this paper, 60 GHz indoor broadband wireless channels are measured with various configurations in a typical office environment. Measurements are taken at nine positions of the room and the base-station antenna is placed either at the center or at an edge of the measurement room, and the remote-station antenna is of either sharp beam or broad beam type. The RMS delay spread (RDS) and normalized received power (NRP) are estimated from the measurements. Statistical models of the 60 GHz indoor wireless channels are also presented with model parameters from the measured channel data based on the Salehs (1987) indoor channel modeling method. Bit error rate (BER) simulations are performed using measured and simulated channel impulse responses with DQPSK-OFDM modulation, respectively. Using sharp beam antenna results in superior performances to using broad beam antenna in terms of both bit error rates (BER) and NRP penalty. Also, placing the base-station antenna at the center is superior to placing it at an edge in terms of BER and NRP.

WLC05-1: A Cognitive Radio (CR) System Employing A Dual-Stage Spectrum Sensing Technique : A Multi-Resolution Spectrum Sensing (MRSS) and A Temporal Signature Detection (TSD) Technique

Spectrum sensing technology is most vital to the implementation of a CR system using dynamic spectrum resource management. This paper suggested a CR system architecture with a wideband dual-stage spectrum sensing technique - a coarse and a fine spectrum sensing. Specifically, a coarse spectrum sensing technique adopted wavelet transforms in this architecture to provide a multi-resolution spectrum sensing (MRSS) feature. Analog implementation of the MRSS block offers wideband, low-power, and real-time operation. A fine spectrum sensing technique used the beneficial properties of auto-correlation in time domain - temporal signature detection (TSD). This TSD technique enables identifying the unique signature feature of each specific signal type. Moreover, this feature detection technique in time domain realizes simple and fast spectrum-detection compared to spectral feature detection methods.

Analog integrator and analog-to-digital converter effect on a Multi-Resolution Spectrum Sensing (MRSS) for cognitive radio systems

The proposed multi-resolution spectrum sensing (MRSS) technique is a flexible, low-power, high-speed spectrum-sensing solution for cognitive radio systems. Meanwhile, impairments of analog building blocks may degrade the accuracy of the proposed MRSS performance. In this paper, the effect of non-idealities of an integrator is explored. The dominant pole position is suggested to be less than 20% of the spectrum-sensing resolution- bandwidth. Then, the quantization effect of an analog-to-digital converter (ADC) is addressed when one of a linear amplifier and logarithmic amplifier is present in front of the ADC, respectively. A 7-bit ADC is suggested when a high-dynamic- range logarithmic amplifier is accompanied.

Millimeter-wave universal test bed (MUTB) for high speed communication systems: system architecture and measurement

This paper reports a new simulation method using software based millimeter-wave test bed that has been developed to emulate a wide range of millimeter-wave communication concepts in the hardware-in-the-loop-simulations and to evaluate an advanced signal processing algorithm for the high speed communication. The system description of the test bed architecture and the implementation of a millimeter-wave transceiver of 38 and 60 GHz are presented. To evaluate the test bed performance, the BERs and the constellations are measured.