| Patent application number | Description | Published |
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| 20100104042 | COMMUNICATION SYSTEM, TRANSMISSION DEVICE, RECEPTION DEVICE, AND COMMUNICATION METHOD - There is provided a communication system capable of achieving a high usage efficiency of frequencies without the need for cooperation of multiplexed users. A communication system communicates over frequency channels set by dividing a frequency bandwidth assigned to the system allows interference between channels by overlapping the adjacent frequency channels with each other in the frequency domain, or a transmitting and receiving device, which transmits and receives a signal by allowing the interference between symbols at a waveform level for each channel to decrease the occupied bandwidth, is provided with ICI removal and ISI compensation filter | 04-29-2010 |
| 20110080884 | COORDINATED TRANSMISSION METHOD, COORDINATED TRANSMISSION SYSTEM, CENTRAL STATION AND RADIO BASE STATION - A coordinated transmission method of the invention has the steps of selecting a directional pattern corresponding to an area in which a radio terminal locates, from among a plurality of directional patterns determined respectively corresponding to a plurality of resources in frequency domains where the plurality of directional patterns is configured so that a plurality of radio base stations surrounding the area transmits, to the area, directional beams of same frequency domain resources to face one another, while not transmitting the directional beams of the same frequency domain resources using the same frequency domain resources to areas adjacent to the area, and of distributing a signal to transmit to the radio terminal according to the selected directional pattern, determining a frequency domain and directions of directional beams regarding the distributed signal, and delivering the signal to each of the plurality of radio base stations that simultaneously transmits the signal to the radio terminal. | 04-07-2011 |
| 20110188540 | RADIO COMMUNICATION SYSTEM, RADIO BASE STATION APPARATUS AND COMMUNICATION CONTROL METHOD - The present invention provides a radio communication system which includes a plurality of radio base station apparatuses that transmit reference signals orthogonal to each other among a plurality of transmitting antennas and a mobile terminal apparatus that performs channel estimation based on the reference signals transmitted from the plurality of radio base station apparatuses, sets priority among a plurality of neighboring radio base station apparatuses and introduces a bias in the number of reference signals that can be allocated to each radio base station apparatus according to the priority from the radio resources shared among the plurality of neighboring radio base station apparatuses. | 08-04-2011 |
| Patent application number | Description | Published |
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| 20090280760 | RADIO COMMUNICATION APPARATUS AND RADIO COMMUNICATION METHOD - A disclosed radio communication apparatus transmits a radio signal to multiple users via multiple transmit antenna groups at appropriate transmit power levels, each of the transmit antenna groups including one or more transmit antennas, the transmit antenna groups having respective transmit power constraints. The apparatus includes a precoding unit configured to perform precoding on signals modulated for individual users and generate transmit weights, an optimum transmit power calculation unit configured to receive the transmit weights from the precoding unit and use components of the transmit weights and respective transmit power limit values for the transmit antenna groups to calculate an initial value for a transmit power optimization problem for calculation of the appropriate transmit power levels for the users, and a transmission unit configured to transmit radio signals at the calculated transmit power levels. | 11-12-2009 |
| 20090280855 | RADIO COMMUNICATION APPARATUS AND RADIO COMMUNICATION METHOD - A disclosed radio communication apparatus includes a preceding unit configured to precode multiple streams, a splitting unit configured to split the precoded streams into two or more stream sets each including one or more streams, a sub power optimization unit configured to execute an iterative transmit power optimization algorithm on each of the split stream sets to determine respective transmit power levels for the individual stream sets, a power optimization unit configured to execute the iterative transmit power optimization algorithm by using the determined transmit power levels as initial values for the iterative transmit power optimization algorithm to determine respective transmit power levels for the individual streams, and a transmission unit configured to transmit radio signals from individual transmit antennas at the determined transmit power levels. | 11-12-2009 |
| 20090280856 | RADIO COMMUNICATION APPARATUS AND RADIO COMMUNICATION METHOD - A disclosed radio communication apparatus includes a preceding unit, a optimum transmit power calculation unit and a transmission unit. The optimum transmit power calculation unit receives the transmit weight related information from the preceding unit and calculates a transmit power level to optimize an objective function in accordance with an interior point method. The objective function results from addition of a barrier function adjusted with a barrier parameter to an original objective function associated with a constrained optimization problem. The original objective function includes a function of respective channel capacities for individual users derived from the transmit weight related information. The optimum transmit power calculation unit adaptively updates a logarithm of the barrier parameter and uses a gradient obtained through a high-order derivative with the logarithm of the barrier parameter to calculate the transmit power level to optimize the resulting objective function. | 11-12-2009 |
| 20100272211 | RADIO COMMUNICATION APPARATUS AND METHOD - A disclosed radio communication method includes precoding modulated information signal sequences to calculate transmit weight information, setting initial transmit power based on prior information including the calculated transmit weight information, generating an objective function of a user channel capacity for a constrained optimization problem based on the transmit weight information and the initial transmit power, generating a new objective function by adding a barrier function to the objective function, using an initial temporary barrier parameter to initiate iteration of an optimization operation for the new objective function, setting an initial barrier parameter based on comparison between the current and previous outputs, calculating transmit power to optimize the new objective function in accordance with an interior point method based on the initial transmit power and the initial barrier parameter and allocating the calculated transmit power to the respective transmit antennas. | 10-28-2010 |
