Byoung-Hak Kim

An IEEE 802.15.4g SUN OFDM-based RF CMOS transceiver for Smart Grid and CEs

The proposed SUN OFDM-based RF CMOS transceiver, with replacement of ZigBee, can be used as not only an energy saving intelligent green home, which is related to Smart Grid, but also an universal remote controller, a Building Automation, and so on. With our proposed SUN OFDM RF transceiver, wireless connectivity among CEs (Consumer Electronics) devices and electric meters can save electronic energy and make lives more comfortable. The proposed RF transceiver consists of a RF front-end, a TX BBA (Base Band Analog), a RX BBA, and a PLL. Re-using of a LC resonator in the RF front-end can reduce the chip size of RF transceiver, DC power consumption, and the cost. The proposed RF transceiver is implemented in a 0.18-μm CMOS technology and consumes 37-mA in TX and 38-mA in RX mode from a 1.8-V supply voltage. In addition, with a fabricated RF transceiver chip, we have succeeded a public demonstration.

An IEEE 802.15.4g sun compliant MR-OFDM RF CMOS transceiver for smart grid and CES

This paper proposes an IEEE 802.15.4g SUN OFDM-based 920 MHz RF CMOS transceiver. It can be adopted in energy saving intelligent green homes, which are related to Smart Grid, as well as universal remote controller, building automation, which is related to CEs (Consumer Electronics), and other areas. With the proposed SUN OFDM-based RF transceiver, wireless connectivity among CE devices or among electric metering systems can considerably save electronic energy and make our lives more comfortable. The proposed RF transceiver consists of a RF front-end with an on-chip RF switch, a Tx BBA (Baseband Analog), a Rx BBA, and a PLL. The proposed RF transceiver is implemented in 0.18-μm CMOS technology and consumes 37 mA in Tx mode and 38 mA in Rx mode from a 1.8 V supply voltage. With the fabricated RF transceiver chip, two successful public demonstrations have been carried out, which show the possibility of its use in commercial products.

Packet detection scheme using cross correlation and complex multiplication in MB-OFDM UWB system

In this paper, we introduce a low power consumption packet detection scheme based on cross correlation and complex multiplication for MB-OFDM UWB system. The proposed scheme compares received signal power and calculated value explained later. The received signal is filtered by a correlator and then output of the correlator is multiplied with delayed output of the correlator and then we get the calculated value which is absolute value of output of complex multiplier. Filter tap coefficient of the correlator is given as sign value of known preamble. This scheme improves packet detection performance in multi-path fading channel model for MB-OFDM UWB system. Through the simulation for 4 block-fading channels, we describe that the proposed scheme can shrink degradation of packet detection performance due to any sampling timing offset and the fading channel model environment for MB-OFDM UWB system.

Joint Carrier Recovery and Turbo Decoding Method for TDMA Burst MODEM Under Very Low SNRs

In this paper, we propose the enhanced carrier recovery algorithm for very low SNR environment. Especially, in order to increase an accuracy of residual frequency and phase offset estimation under very low SNR with constraints of power-limited communication system, it is achieved by comparing the phases between soft decision outputs of code symbols and the channel symbols at the each turbo decoding iteration. As the number of iteration increases, residual freq. and phase offset are compensated and thus the reliability of the soft decision output at next iteration is increased. In consequence, the complementary cooperation between iteration decoding and carrier recovery improves the final coded BER performance. The proposed techniques can fulfil the stringent up-link link budgets at Ka band by operating at very low SNR

Preamble generation method to improve timing estimation for OFDM system using training sequence

A novel preamble structure is proposed for a timing estimation for orthogonal frequency division multiplexing (OFDM) systems such as the IEEE 802.11 and the IEEE 802.15.4g/4m. The boundary estimation becomes easy because of the outstanding correlation property between the short training sequence (STS) and the proposed long training sequence (LTS). The proposed method can be applied to OFDM systems which use STS and LTS preamble structures. The proposed LTS scheme considerably improves the performance of timing estimation in comparison with the method of using legacy LTS. This method has been applied to the IEEE 802.15.4m standard.

Implementation of IEEE 802.15.4g wireless communication platform for smart utility service

Smart home utility network is the last mile of smart grid network. Although some wireless technologies such as ZigBee or Wi-Fi have been used for home utility service, they have disadvantages such as cost, power consumption, and network topology. To overcome the problems, a new wireless technology has been introduced in IEEE 802.15.4g standard. In this paper, we implement IEEE 802.15.4g communication platform and show possibilities of smart home utility service using the implemented platform. We firstly introduce an architecture of the implemented platform. Then, we show the demonstration of smart home utility service and water metering service using the platform which includes IEEE 802.15.4g OFDM and FSK features.

A study of detection algorithm for DAA regulation of Korea using MB-OFDM UWB receiver

This paper analyzed the performance of a detection algorithm using MB-OFDM UWB receiver based on silent time when the victim signal is received by detection limit of -80 dBm/MHz proposed in Korea for DAA. Simulation results show that the performance of the proposed detection algorithm is enough to detect the victim signal with 95% detection probability within the +/-0.5 dB error range if repeat Number over 4 is used.

Design of the robust demodulator for mobile broadband satellite Internet access system

In this paper, we propose a robust demodulator structure for mobile broadband satellite Internet access systems. Especially, in order to achieve good synchronization under very low SNR, a large frequency offset, and Doppler frequency offset, with the constraints of mobile satellite communication, we design a demodulator which has robust algorithms for carrier frequency recovery compared with the conventional algorithms. The proposed technique can fulfill the stringent up-link link budgets at Ka band by operating at very low SNR.

Optimal capacity assignment in interactive satellite return channels for mobile multimedia services

We develop an efficient method for optimal capacity assignment in an interactive satellite multimedia system using hybrid CDMA/TDMA channels. We mathematically formulate a throughput-maximizing capacity assignment problem as a binary integer programming (BIP) problem, and decompose this BIP problem into two subproblems. With this decomposition, we promote the computational efficiency in finding the optimal solution of the original BIP problem.

An open-loop power control method for mobile satellite system

In this paper, we propose an architecture of open-loop power control, which is applicable to Ku/Ka-band mobile satellite systems. When a mobile terminal tries to access a HUB system initially, the location of the mobile terminal is not fixed. If the transmission power of the mobile terminal is in a low state, the probability of initial access failure may be increased. For this, we propose an open-loop power control method which can be applied to mobile terminals which are located in any beam coverage. In the mobile environment, a communication channel can be changed dynamically, and our architecture can work in a dynamic environment.