Ik Soo Jin

Design and Implementation of Efficient Reed-Solomon Decoder for Intelligent Home Networking

Intelligent home concept is the integration of different services within a home by using a common communication system. Error correction coding is being used on an almost routine basis in most communication systems including intelligent home networking. In addition, critical protocol management information requires high fidelity forward error correction (FEC) coding to ensure that the protocol functions correctly in the worst case situations. A powerful technique in the worst case situations is a Reed-Solomon (RS) code. With this technique, one achieves a high level of performance by trading an increase in overall block length for a reduction in hardware complexity. This paper concerns the design and implementation of RS codec for intelligent home networking. The 3 symbol error correcting RS codec is developed on field programmable gate array (FPGA) chips using very high speed integrated circuit hardware description language (VHDL). The logic functions are confirmed by VHDL simulator tool. The circuits are generated by the synthesis tool. Two FPGA chips are required and the FPGA utilization is 70% and 40%, respectively.

Interoperation of an UHF RFID Reader and a TCP/IP Device via Wired and Wireless Links

A main application in radio frequency identification (RFID) sensor networks is the function that processes real-time tag information after gathering the required data from multiple RFID tags. The component technologies that contain an RFID reader, called the interrogator, which has a tag chip, processors, coupling antenna, and a power management system have advanced significantly over the last decade. This paper presents a system implementation for interoperation between an UHF RFID reader and a TCP/IP device that is used as a gateway. The proposed system consists of an UHF RFID tag, an UHF RFID reader, an RF end-device, an RF coordinator, and a TCP/IP I/F. The UHF RFID reader, operating at 915 MHz, is compatible with EPC Class-0/Gen1, Class-1/Gen1 and 2, and ISO18000-6B. In particular, the UHF RFID reader can be combined with the RF end-device/coordinator for a ZigBee (IEEE 802.15.4) interface, which is a low-power wireless standard. The TCP/IP device communicates with the RFID reader via wired links. On the other hand, it is connected to the ZigBee end-device via wireless links. The web based test results show that the developed system can remotely recognize information of multiple tags through the interoperation between the RFID reader and the TCP/IP device.

A System Implementation for Cooperation between UHF RFID Reader and TCP/IP Device

This paper presents a system implementation for cooperation between UHF RFID reader and TCP/IP device that can be used as a home gateway. The system consists of an UHF RFID tag, an UHF RFID reader, a RF end-device, a RF coordinator and a TCP/IP I/F. The UHF RFID reader is compatible with EPC Class-0/Gen1, Class-1/Gen1, 2 and ISO18000-6B, operating at the 915MHz. In particular, UHF RFID reader can be combined with a RF end device/coordinator for ZigBee(IEEE 802.15.4) interface which is low power wireless standard. The TCP/IP device is communicated with RFID reader via wired type. On the other hand, it is connected with ZigBee end-device via wireless type. The experimental results show that the developed system can provide the right networking.

The Improved Space-Time Trellis Codes with Proportional Mapping on Fast Fading Channels

The use of multiple antennas in most future mobile communication systems seems to be inevitable. Today, the main question is how to include multiple antennas and what are the appropriate methods for specific applications. In this paper, a space-time trellis code (STTC) with proportional mapping is proposed in order to improve the bit error rate (BER) performance. The core of proportional mapping assigns information bits with a Hamming distance in proportion to the sum of the Euclidean distance to each trellis branch of STTC. Following these rules, we can construct 8-state 8-PSK STTC with proportional mapping. To the best knowledge, this combination has not been considered yet. The BER performance is examined with simulations and the performance of proportional mapping is compared to that of well known natural mapping and Gray mapping on both fast Rayleigh as well as fast Rician fading channels. It is shown that in case of 8-state 8-PSK STTC, proportional mapping outperforms Gray mapping and natural mapping by about 0.5 dB and about 0.7 dB at a BER of 10− 5, respectively, over fast Rician fading channels, without any additional loss.

The space-time trellis codes with improved performance for fading channels

The one motivation of this work stems from the different design criteria between in slow fading channels and in fast fading channels. We presented a new 4-PSK 4-state STTC with two transmit antennas for slow fading channels by improving the design parameters of the code. The other motivation of this work stems from the application of new mapping to STTC to obtain a further performance improvement. We refer the new mapping as proportional mapping. The 8-state 8-PSK STTC with proportional mapping is presented. From the simulation results, it is shown that new code is superior to the corresponding TSC code and the BBH code over slow fading channels. It is also shown that in case of 8-state 8-PSK STTC, proportional mapping outperforms Gray mapping and natural mapping over fast Rician fading channels.

All-Optical RZ-to-NRZ Converted Data Transmission at 10 Gb/s

This paper proposes and demonstrates a novel all-optical return-to-zero (RZ) to nonreturn-to-zero (NRZ) data format conversion using a semiconductor optical amplifier (SOA) loop mirror. The format conversion has been performed between the most widely used data formats—NRZ and RZ formats. The format conversion scheme is based on gain variation by an intensity-dependent phase change in an SOA-loop mirror. 10 Gb/s error-free fiber transmission up to 78 km for the converted NRZ format data is achieved. Further, the proposed method shows improved transmission performance than the conventional Mach-Zehnder modulation technique.

The Improved 4-PSK 4-State Space-Time Trellis Code with Two Transmit Antennas

Space-time coding is a powerful technique to improve the error performance of wireless communications systems by using multiple transmit antenna. In this paper, a new 4-PSK 4-state space-time trellis codes (STTCs) with two transmit antennas for slow fading channels is presented by improving the design parameters of the code. From the simulation results, it is shown that new code is superior to the TSC code and the BBH code by about 0.2 dB at a BER of 10− 4 over slow Rayleigh fading channels, about 0.4~1.3 dB over slow Rician fading channels. Moreover, it is also shown that new code with Gray mapping can be obtained gains by about 0.1~0.6 dB while keeping the complexity almost the same as the code with natural mapping.

Performance of DS/SSMA systems with MTCM codes

We examine the use of multiple trellis coded modulation (MTCM) codes for a direct sequence spread spectrum multiple access (DS/SSMA) system for fading channels, and compare the results with Boudreau et al.s (1990) system, in which the use of standard Ungerboeck type trellis codes in conjunction with a DS/SSMA system has been considered. A generalized transfer function method is used to evaluate upper bounds on bit error probability. Multiple access interference due to K asynchronous users transmitting simultaneously is computed using the method of moments. From the calculations and results, it is shown that DS/SSMA system with MTCM codes achieves better performance than the Boudreau et al.s system.