Patent application number | Description | Published |
20080232320 | Dynamic Resource Allocation Method Based on Frequency Reuse Partitioning For Ofdma/Fdd System, and Frame Transmission Method Therefor - Provided are a dynamic resource allocation method based on frequency reuse partitioning for an Orthogonal Frequency Division Multiple Access (OFDMA) system, and a frame transmission method therefor. The dynamic resource allocation method includes: a) dividing a coverage into cells based on frequency reuse partitioning; b) selecting a candidate user to receive a channel allocated thereto based on the ratio; c) acquiring distance information for the candidate user; and d) checking whether the candidate user is in an inner or outer cell area based on the distance information. If the candidate user is in the inner cell area, a subchannel group among subchannel groups having a Frequency Reuse Factor (FRF) lower than a threshold value is selected and subcarriers of the selected subchannel group is allocated. If the candidate user is in the outer cell area, a subchannel group among subchannel groups having a FRF higher than the threshold value is selected. | 09-25-2008 |
20080248753 | Method and apparatus for retransmitting data based on antenna scheduling in MIMO system - Provided is a method for retransmitting data based on antenna scheduling in a MIMO system to which a spatial multiplexing technique is applied. The method includes the steps of: (a) at a transmitter side, modulating an input packet into transmittable data to transmit to a receiver side; (b) at the receiver side, estimating channel values from the packet transmitted from the transmitter side, and selecting transmitting and receiving antennas for transmitting the next packet from the estimated channel values; (c) detecting whether an error is present in the packet or not, and transmitting a feedback signal to the transmitter side, the feedback signal including information on whether or not to transmit the packet and a list of the selected transmitting antennas; and (d) at the transmitter side, retransmitting the transmitted packet or transmitting the next packet through the transmitting antennas designated by the receiver side depending on the feedback signal. | 10-09-2008 |
20090196362 | TRANSMISSION METHOD AND APPARATUS FOR ALLOCATING SUBCHANNEL AND FORMING STATIONARY BEAM TO MAXIMIZE TRANSMISSION EFFICIENCY IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING/MULTIPLE ACCESS BASED WIRELESS COMMUNICATION SYSTEM - Provided are a transmission method and apparatus for allocating a subchannel and forming a stationary beam to maximize transmission efficiency in an OFDMA based wireless communication system. The method includes determining the subchannel for the equipment of each user based on the channel state of the equipment of each user, determining a beam index for the equipment of each user, based on location information and direction of arrival information of the equipment of each user, generating an OFDM symbol by mapping a modulation symbol corresponding to the equipment of each user to the determined subchannel, and transmitting the generated OFDM symbol to a wireless space by forming a beam following the determined beam index. Using the method, the equipment of each user can be allocated with an advantageous subchannel, can remove an interference signal at low cost, and can increase total throughput of an OFDMA system downlink. | 08-06-2009 |
20090316635 | Method and frame structure for supporting dynamic channel allocation and dynamic power allocation in frequency reuse partitioning based OFDMA system - Provided are a dynamic channel/power allocation method for an FRP-based OFDMA system and a frame/slot structure. capable of supporting the dynamic channel/power allocation method. In the FRP-based OFDMA system, each of cells has an inner cell, an outer cell and a plurality of sectors and performs data communication with a plurality of MSs therein through one or more orthogonal subchannel groups. In the dynamic channel/power allocation method, a BS receives a feedback channel condition from an MS provided with a service of the BS and allocates a subchannel group with a high SINR to each MS in consideration of the fairness and the distance information of each MS. Power is allocated to each MS on the basis of the conditions of a channel allocated to each MS, thereby obtaining a multi-user diversity gain. | 12-24-2009 |
20100182897 | SIGNAL DETECTING METHOD FOR SPATIAL MULTIPLEXING MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEMS - A method for detecting signals in spatial multiplexing multiple-input multiple-output (MIMO) systems using a QR-decomposition with M (QRD-M) algorithm is provided. The method includes receiving signals, limiting upper and lower bounds of a complexity in a QR-decomposition with M (QRD-M) algorithm, and detecting the received signals using the QRD-M algorithm. The signal detecting method can effectively reduce the amount of operation generated while detecting signals, using the QRD-M algorithm where the upper and lower bounds of the complexity are limited. | 07-22-2010 |
20110044407 | ADAPTIVE QRD-M ALGORITHM BASED SIGNAL DETECTING METHOD BY USING CONSTELLATION SET GROUPING IN SPATIAL MULTIPLEXING MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEM - There is provided a signal detecting method using constellation set grouping in a spatial multiplexing multiple input multiple output system. The signal detecting method includes dividing a set of candidate symbols, a constellation set into a plurality of subsets by grouping the constellation set; dividing a tree search process of a QR-decomposition with M-algorithm (QRDM) algorithm into a plurality of partial detection phases; and performing the plurality of divided partial detection phases in parallel or iteratively. | 02-24-2011 |
20110058470 | RANGING APPARATUS AND METHOD FOR IMPROVING RANGING PERFORMANCE IN OFDMA SYSTEM - Disclosed herein is a ranging apparatus and method. The ranging apparatus includes a correlation unit for correlating OFDMA reception signals with inverse fast Fourier transformed ranging codes, and outputting correlation result values. A threshold determination unit determines a threshold value depending on characteristics of the reception signals. A comparison unit estimates a delay time by selecting a maximum value from among the correlation result values, and detects a ranging code by comparing the maximum value with the threshold value, and then outputs and feeds back the ranging code and the delay time when the maximum value is equal to or greater than the threshold value. A weight multiplication unit delays the ranging code by the delay time, multiplies a weight by the delayed ranging code, and outputs a resulting value. A calculation unit subtracts the resulting value from the reception signals, and provides adjusted reception signals. | 03-10-2011 |
20140293906 | SYSTEM AND METHOD TO MITIGATE INTERFERENCE OF 3GPP LTE HETEROGENEOUS NETWORK ACCORDING TO PRIORITY OF SERVICE - A power control system and method to mitigate interference in a heterogeneous network is provided. A power control method to mitigate interference may include: receiving a link connection request from a femto terminal; transmitting a downlink signal when the link connection request is allowed; receiving information of a macro terminal present around a femto base station; controlling a power of the downlink signal in response to a high interference indicator (HII) report being included in the received information of the macro terminal; and controlling the power of the downlink signal based on a priority of service while satisfying predetermined constraints, in response to the HII report in a state in which the power of the downlink signal is decreased up to a predetermined required power. | 10-02-2014 |
20140295872 | SYSTEM AND METHOD TO ALLOCATE FREQUENCY DYNAMICALLY BASED ON PRIORITY OF QUALITY OF EXPERIENCE (QoE) IN 3GPP LTE HETEROGENEOUS NETWORK - A method and system to dynamically allocate a frequency based on a priority of quality of experience (QoE) is disclosed. A method to dynamically allocate a frequency may include: securing a predetermined frequency band and a bonus frequency band for a macrocell; allocating the predetermined frequency band and the bonus frequency band to a macro terminal located in the macrocell; allocating the bonus frequency band based on the priority of service in a subsequent time slot when a frequency band comprising the predetermined frequency band and the bonus frequency band is not allocated to the macro terminal. | 10-02-2014 |