Jong-Ryul Lee

A 2×2 MIMO tri-band dual-mode CMOS transceiver for worldwide WiMAX/WLAN applications

This paper describes a fully integrated 130nm CMOS 2×2 MIMO tri-band dual-mode transceiver for fixed and mobile WiMAX and IEEE 802.11a/b/g/n applications. The transceiver features reduced RF interface (only 4 RF pins) with the wideband circuit topology of the LNA and drive amplifier that minimizes the performance degradation. The measured receive path NF is 3.6~4.2, 4.2~4.7, and 5.4~6.2dB for the 2/3/5GHz bands respectively. The measured integrated phase noise from 1kHz to 10MHz is 0.5/0.8/0.95 rms degree for 2/3/5GHz bands respectively. The transceiver ensures low EVM over the wide dynamic range due to highly linear RX and TX signal paths, and low integrated PLL phase noise characteristics.

A 2×2 MIMO multi-band RF transceiver and power amplifier for compact LTE small cell base station

We present a fully integrated 2×2 MIMO CMOS LTE RF transceiver along with multi-band InGaP/GaAs HBT power amplifiers for LTE-A small cell (femtocell) base stations. The transceiver features highly integrated LNAs and drive amplifiers with 24 individual RF I/O pins. The multi-band PAs achieves ACLR <-45dBc at 25dBm with PAE >38% at 33dBm by employing a third-order intermodulation distortion (IMD3) canceling techniques. The presented SiP composed of proposed radio and PAs shows plenty of margins in radio conformal test of femtocell base station using a commercial modem.

A Triple-Band Transceiver Module for 2.3/2.5/3.5 GHz Mobile WiMAX Applications

A triple-band transceiver module for 2.3/2.5/3.5 GHz mobile WiMAX, IEEE 802.16e, applications is introduced. The suggested transceiver module consists of RFIC, reconfigurable/multi- resonance MIMO antenna, embedded PCB, mobile WiMAX base band, memory and channel selection front-end module. The RFIC is fabricated in 0.13μm RF CMOS process and has 3.5 dB noise figure(NF) of receiver and 1 dBm maximum power of transmitter with 68-pin QFN package, 8  8 mm 2 area. The area reduction of transceiver module is achieved by using embedded PCB which decreases area by 9% of the area of transceiver module with normal PCB. The developed triple-band mobile WiMAX transceiver module is tested by performing radio conformance test(RCT) and measuring carrier to interference plus noise ratio (CINR) and received signal strength indication (RSSI) in each 2.3/2.5/3.5 GHz frequency. Index Terms—Transceiver module, triple-Band, mobile WiMAX, IEEE 802.16e, RFIC, embedded PCB

An object-based information retrieval model: toward the structural construction of thesauri

We propose an information retrieval model, where the object-oriented paradigm is applied to the construction of thesauri and the interpretation of user queries. This model provides a mechanism to assist domain experts in constructing thesauri; it determines a considerable part of the relationship degrees between term objects by inheritance, and supplies domain experts with information available from a thesaurus being constructed. It enables domain experts to incrementally construct a thesaurus as well, since the automatically determined degree of relationships can be refined whenever a more sophisticated thesaurus is needed. It may minimize the domain experts burden caused from exhaustive specification of individual relationships. All the relationships between term objects of our thesaurus (called object-based thesaurus) are represented in terms of two levels: concept level and instance level. The former defines the relationships between concepts, whereas the latter specifies the relationships between instances. We also propose a new query evaluation mechanism to exploit the thesaurus when interpreting the intent of user queries.

A CMOS Implementation Of CDMA/FM IF Signal Processor

A CDMAiFM IF IC is implemented using 0.8 pm 2-metal 2-poly CMOS process. This IC integrates both CDMA and FM IF signal processing functions required for dual mode cellular phone. Rx and Tx frequencies are 85.38 MHz and 130.38 MHz, respectively. The chip size is 5.5 x 6.3 mm2 and the maximum power consumption is 230 mW.

A 65nm CMOS 2×2 MIMO multi-band LTE RF transceiver for small cell base stations

This paper describes a fully integrated 65nm CMOS 2×2 MIMO multi-band LTE RF transceiver for small cell (femtocell) base stations with frequency support from 680MHz to 6GHz. The transceiver features highly integrated RF front-ends including single-ended LNAs and drive amplifiers with total 32 individual RF I/O pins. The receiver shows NF of 2.9∼5.2dB, HP3 of >-2dBm, and HP2 of >48dBm over the entire frequency range at maximum gain. The transmitter shows ACLR of <−55dBc at −5dBm output power with <−157dBc/Hz out-of-band phase noise. The proposed RF transceiver mounted in the prototype of Femtocell base station using a commercial power amplifier and modem shows plenty of margins in the radio conformal test.

A 3.3 V 0.8 /spl mu/m CMOS single chip IF IC for CDMA/FM cellular phone

A 3.3 v 150 mW IF IC is implemented using 0.8 /spl mu/m CMOS process. This IC integrates both CDMA and FM IF signal processing units and interfaces between IF signals and baseband modem. Rx mixer down-converts 85.38 MHz IF signals into baseband signal, and Tx mixer based on a replica transconductor up-converts baseband signal into a 130.38 MHz IF signal. The chip size is 5.5/spl times/6.3 mm/sup 2/.