Electronics and Telecommunications Research Institute

Samsung Electronics Co., Ltd.

Korea Advanced Institute of Science and Technology

Jong-sub Cha

Jong-Suk Chae

Seung-Il Myong

Heyung-sub Lee

Jong-Ho Lee

Sang-Boh Yun

Joo-Hyun Lee

Kyung-Ho Park

Sung-Soo Hwang

Keon-Kook Lee

Sung-Yoon Jung

Hoe-Sung Yang

Joonhyuk Kang

Namseok Chang

Kang-bok Lee

Sang-hyun Mo

Disclosed is a wireless signal receiving apparatus, and more particularly, disclosed is a parallel automatic frequency offset estimation apparatus and method for tracking a frequency offset in an early stage by calculating, in parallel, frequency offsets of a received signal. The parallel automatic frequency offset estimation apparatus includes a receiving unit to receive a data frame; and a frequency offset estimation unit to calculate, in parallel, frequency and phase deviations at different bit intervals within a particular section of the received data frame, to add together the frequency and phase deviations to obtain a first sum of the frequency and phase deviations, and to add the first sum to a frequency phase deviation calculated for each bit after the particular section in the received data frame to obtain a second sum of the frequency and phase deviations. Accordingly, transmission frequency tracking can be performed at higher speed, compared to the conventional systems in which frequency offset acquisition is carried out in stages. Also, accurate tracking of a transmission frequency is possible in an initial frame.

Parallel automatic frequency offset estimation method and apparatus

An active radio frequency identification (RFID) apparatus having an additional transmitter in addition to a single transmitter is provided. The active RFID apparatus includes a first transmitter including a first pseudo noise (PN) code generator to generate a direct sequence spread spectrum (DSSS) introduced by ISO/IEC (International Organization for Standardization/International Electrotechnical Commission) 24730-2 or ISO/IEC 18185-5 type B; and a second transmitter including a second PN code generator to perform an AND operation on an initial value and a fed back value and shift the resultant value of the AND operation, to perform an XOR operation on particular bits from among the shifted bits and to perform an XOR operation again on the shifted bits and the resulting value of the XOR operation to finally generate a PN code. Accordingly, where an additional PN code is added besides an existing PN code, a PN code having excellent auto correlation characteristics allowing discrimination of the PN code itself and cross-correlation characteristics providing a code discrimination ability with respect to another code can be generated.

Active RFID apparatus for improving PN code generation

An iterative tree search-based preceding method for a multi-user Multi-Input Multi-Output (MIMO) communication system includes determining a reference value of a cumulative branch metric of a candidate symbol, eliminating candidates having values that exceed the determined reference value of the cumulative branch metric of the candidate symbol, and registering values, which do not exceed the determined reference value of the cumulative branch metric of the candidate symbol, as entries, and selecting the least value from the values registered as the entries. Thereby, the method has low complexity and similar performance compared to an existing Sphere Encoding (SE) technique.

Iterative tree search-based precoding technique for multiuser MIMO communication system

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Seoul, South Korea

Jong-sub Cha