Showing papers by "Younsun Kim published in 2005"

Apparatus and method for transmitting a data stream in a wireless communication system with multiple antennas

Abstract: An apparatus and method for determining a transmission unit for data stream transmission in a wireless communication system in which multiple transmission and reception antennas are used and a receiver provides information on a data stream to be transmitted through a transmission unit A fading estimator calculates fading values from the multiple transmission antennas to the multiple reception antennas A channel quality estimator reverse-orders combined weights for multiple transmission units based on the fading values from the multiple transmission antennas to the multiple reception antennas, successively selects transmission units for data stream transmission among the reverse-ordered transmission units, determines a modulation and coding scheme (MCS) for each of the selected transmission units, and feeds back the MCS to a transmitter

Apparatus and method for transmitting and receiving data in a mobile communication system using an array antenna

Abstract: An apparatus and a method for transmitting and receiving data in a mobile communication system including an array antenna. The method includes the steps of transmitting pilot channels through a transmission antenna while aligning the pilot channels orthogonally to each other, receiving feedback information related to the pilot channels from a mobile station capable of receiving the data, dividing the data to be transmitted into sub-data streams by using the feedback information, and determining a coding rate and a transmit power for the sub-data streams, and converting the sub-data streams into symbol arrays to be transmitted according to the coding rate and the transmit power and transmitting data by converting the data into fixed beams.

Method for transmitting and receiving broadcast service data in an OFDMA wireless communication system

Abstract: A method for providing two or more broadcast services in an orthogonal frequency division multiple access (OFDMA) wireless communication system. The method comprises the steps of separately receiving broadcast services to be transmitted, and independently performing coding, interleaving and modulation on the broadcast services according to a required quality for each of the broadcast services; segmenting each of the modulated broadcast signals into minimum transmission units; time-division-multiplexing the segmented broadcast service signals; configuring a frame comprising information on the broadcast service in physical layer transmission information transmitted together with the broadcast service; and transmitting the frame.

Apparatus and method for interleaving channels in a mobile communication system

Abstract: An apparatus and method interleaving symbols coded by a turbo encoder in a communication system that uses the turbo encoder for encoding transmission information into coded systematic symbols and at least one parity symbol pair, and maps the coded symbols using a second or higher modulation order before transmission. An interleaver controller performs a control operation of cyclic-shifting the systematic symbols among the symbols coded by the turbo encoder depending on a size of a physical packet to be transmitted, the number of transmission slots, and the modulation order, using an equation of (K×c+k) mod R, and cyclic-shifting redundancy symbols constituting the remaining size of the coded symbols to be transmitted, using an equation of floor{(K×c+k)/D}mod R. An interleaver cyclic-shifts input symbols under the control of the interleaver controller.

Performance evaluation of high-speed packet enhancement on cdma2000 1/spl times/EV-DV

Abstract: During the last few years, the cdma2000/spl reg/ cellular system has undergone a major enhancement within the 3rd Generation Partnership Project 2. The objective of this enhancement was to improve the bandwidth efficiency of the cdma2000 system by creating a new set of high-speed packet data channels, the forward packet data channel and the reverse packet data channel. This new set of high-speed packet data channels utilize technologies such as fast packet scheduling, hybrid automatic repeat request, and adaptive modulation and coding. This article discusses the performance evaluation aspect of the high-speed packet enhancement of cdma2000 revisions C and D, the so-called 1/spl times/EV-DV system. Insights into how the performance evaluations of cdma2000 revisions C and D were conducted, and the results of these evaluations are discussed.

An efficient radio resource management technique for the reverse link in cdma2000 1xEV-DV

Abstract: This paper studies the problem of efficient exploitation of the available bandwidth on the reverse link (RL) of cdma2000 1/spl times/EV-DV system. The objective is to maximize user throughput and to minimize packet delay while ensuring that forward link (FL) overhead is as low as possible. Two radio resource management (RRM) mechanisms, the time-scheduled (TS) scheme and the rate-controlled (RC) scheme, which can be used as the RRM schemes for the RL of 1/spl times/EV-DV are introduced and compared. It is shown that the RC scheme offers a better sector throughput through higher rise-over-thermal (RoT) utilization with less FL overhead, while the TS scheme outperforms the RC scheme in terms of packet delay through the capability of fast rate adaptation. In addition, a hybrid RRM scheme, namely rate control with quick start (RCQS) is introduced to combine the advantages of the TS and RC schemes. It is shown that the throughput and delay of the RCQS are comparable to those of the RC scheme the TS scheme, respectively.