Lg Electronics Inc.

Lg-ericsson Co., Ltd.

Ericsson-lg Co., Ltd.

Hyuck Chan Kwon

Hee Gul Park

Jung Seung Lee

Byoung Seong Park

Joon Kui Ahn

Dong Joo Park

Sung Lark Kwon

Jae Won Jang

Hoo Young Jeong

Young Kwon Ryu

Hong Jik Kim

Seung Hoon Hwang

Hoo Young Neuti Maeul Jugong Jeong

Dong Joo Neuti Maeul Jugong Park

Embodiments of the present invention may provide an apparatus and a method for transmitting and receiving a random access channel (RACH) in a single carrier-frequency division multiple access (SC-FDMA) system. A frequency domain RACH signal may be mapped to a localized sub-frequency band of an entire frequency band available to the SC-FDMA system. A guard band including at least one sub carrier may be allocated between the RACH signal band and other channel signal bands. A guard time may be allocated between the RACE signal and other channel signals in the time domain. The RACH signal may include a short message including information related to a mobile station. The RACE signal may be detected in a frequency based method, a time based method or a sliding matched filter based method. Receiver complexity can be decreased if the RACH signal includes a CAZAC code sequence for a preamble. In such a case, a receive delay may be simply calculated and then adjusted more accurately.

Apparatus and method for transmitting and receiving a RACH signal in SC-FDMA system

Embodiments of the present invention may provide an apparatus and a method for transmitting and receiving a random access channel (RACH) in a single carrier-frequency division multiple access (SC-FDMA) system. A frequency domain RACH signal may be mapped to a localized sub-frequency band of an entire frequency band available to the SC-FDMA system. A guard band including at least one sub carrier may be allocated between the RACH signal band and other channel signal bands. A guard time may be allocated between the RACH signal and other channel signals in the time domain. The RACH signal may include a short message including information related to a mobile station. The RACH signal may be detected in a frequency based method, a time based method or a sliding matched filter based method. Receiver complexity can be decreased if the RACH signal includes a CAZAC code sequence for a preamble. In such a case, a receive delay may be simply calculated and then adjusted more accurately.

An apparatus and a method for interference cancellation using a multi-user multiple input multiple output (MU-MIMO) scheme in a single carrier frequency division multiple access (SC-FDMA) system are disclosed. Received data of every terminal are classified into first received data and second received data. The first received data has lower reliability and the second received data has higher reliability than the first received data. The second received data is transmitted to an upper layer. Interference signals are formed with the second received data based on a channel estimation value. The interference signals are removed from the first received data, and the interference signal free first received data is transmitted to the upper layer.

Interference cancellation with MU-MIMO scheme in SC-FDMA system

The present invention relates to a power controlling method in a mobile radio communication system using Automatic Repeat reQuest (ARQ) scheme, and more particularly to a power controlling method of response (ACK/NACK) signals for transmitting the ACK/NACK signals in different power based on the permissible probabilities of reception error that the system requires. When the ACK/NACK signals are transmitted and received in the automatic repeat request (ARQ) system, since the ACK/NACK signals can be transmitted in accordance with the transmission power satisfying an error rate required in each signal by differentiating the transmission power of the signal according to each ACK/NACK, the power consumption required in the transmission of the ACK/NACK signals can be reduced.

Method and apparatus for transmitting acknowledgement signals

The present invention relates to a power controlling method in a mobile radio communication system using Automatic Repeat reQuest (ARQ) scheme, and more particularly to a power controlling method of response (ACK/NACK) signals for transmitting the ACK/NACK signals in different power based on the permissible probabilities of reception error that the system requires. When the ACK/NACK signals are transmitted and received in the automatic repeat request (ARQ) system, since the ACK/NACK signals can be transmitted in accordance with the transmission power satisfying an error rate required in each signal by differentiating the transmission power of the signal according to each ACK/NACK, the power consumption required in the transmission of the NACK signal can be reduced.

A method for controlling the transmission of data in a radio communications system transmits response signals from a receiver which includes information that reflects received signal quality, as well as information indicating whether an error has occurred in the data transmission. In one case, acknowledgment signals or negative acknowledgment signals may be regarded as no reply and not forwarded to a transmitter. In another case, the signals could be recognized as an acknowledgment or retransmission request by a receiver. Preferably, the signals transmitted from the receiver to the transmitter are composed of more than 2-bit multiplexed information. By transmitting response signals of this type, the transmission efficiency of packet data may be increased, and the automatic repeat request (ARQ) performance by the system may be greatly improved.

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Seoul, South Korea

Hyuck Chan Kwon