Patents by Inventor Ulf Forssén

Ulf Forssén has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6650910
    Abstract: The present invention relates to radio systems and, more particularly, to a method and apparatus for receiving radio signals with the aid of beams generated by antenna assemblies. For each of the beams in a first of the antenna assemblies there is a beam in the second of the antenna assemblies that covers the same space area. Signals received by the second are delayed relative to signals received by the first of the antenna assemblies. Then signals from the first antenna assembly are combined with signals from the second of the antenna assemblies. The combined signals derive from beams covering the same space area. Each combined signal is then radio received in a joint radio receiver. A DOA-estimation can be calculated on the basis of radio received signals derived from all beams.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: November 18, 2003
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Sara Mazur, Bo Hagerman, Ulf Forssén, Sören Andersson, Fredrik Ovesjö
  • Patent number: 6339399
    Abstract: A method and a system for calibrating the reception and transmission of an antenna array for use in a cellular communication system is disclosed. The calibration of the reception of the antenna array is performed by injecting a single calibration signal into each of a number of receiving antenna sections, in parallel. The signals are collected after having passed receiving components that might have distorted the phase and amplitude. Correction factors are generated and applied to received signals. The calibration of the transmission of the antenna array is preformed in a similar way. A single calibration signal is generated and injected into each of a number of transmitting antenna sections, one at a time. The signals are collected, one at a time, after having passed transmitting components that might have distorted the phase and amplitude. Correction factors are generated and applied to signals that are to be transmitted.
    Type: Grant
    Filed: June 26, 2000
    Date of Patent: January 15, 2002
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Sören Andersson, Ulf Forssén, Fredrik Bengt Ovesjö, Sven Oscar Petersson
  • Patent number: 6301238
    Abstract: Directional beam generative apparatus, and an associated method, for a radio communication station forms directional antenna beam patterns for the communication of communication signals with remote communication stations operable in a TDMA communication system. Channels are allocated for effectuation of communications between the radio communication station and the remote stations responsive to indications of locations at which the remote communication stations are indicated to be positioned. Remote communication stations indicated to be positioned within a selected area are allocated to channels formed upon a single carrier.
    Type: Grant
    Filed: January 28, 1997
    Date of Patent: October 9, 2001
    Assignee: Telefonaktiebolaget LM Ericsson (Publ)
    Inventors: Bo Hagerman, Ulf Forssén, Thomas Östman, Hans Mähler
  • Publication number: 20010016504
    Abstract: A radiocommunication system is described wherein a flexible transceiver is provided that can be switchably connected to different antenna structures. Switching matrices are provided between the antenna elements and the receive processing circuitry which, under the control of the central processing unit, allows the transceiver to handle the different antenna structures. The enhanced flexibility achieved by the present invention provides a novel transceiver which can, for example, be reconfigured between and during calls to dynamically assign resources based upon changes in the amount and type of load being experienced by the system and adjusted in order to render existing operating functions more efficient.
    Type: Application
    Filed: April 3, 1998
    Publication date: August 23, 2001
    Inventors: HENRIK DAM, ULF FORSSEN, SOREN ANDERSON, JOHNNY WIDEN, JONAS KARLSSON
  • Patent number: 6173014
    Abstract: Recently, interference rejection combining techniques have been proposed which can increase significantly the performance of the uplink in C/I limited environments. Another interesting property of the IRC techniques is that their C/I performance does not degrade as the correlation between the received signals increases. This feature of IRC techniques is exploited in the present invention to allow for a reduced spacing between the antennas. According to another aspect of the present invention, the performance of the downlink is improved using beamforming techniques to “steer” base station transmissions toward a desired mobile station. In this way, the performance of the downlink is improved using beamforming techniques to a degree similar to that at which the uplink has been improved using IRC techniques. This allows the system designer to more fully exploit the variations in system design associated with improving the uplink performance.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: January 9, 2001
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Ulf Forssen, Thomas {umlaut over (O)}stman, Gregory E. Bottomley
  • Patent number: 6167039
    Abstract: Mobile stations using antenna diversity are described. Techniques for combining CDMA signals received over plural antennas at a mobile unit are provided which suppress interference from undesired base stations.
    Type: Grant
    Filed: December 17, 1997
    Date of Patent: December 26, 2000
    Assignee: Telefonaktiebolget LM Ericsson
    Inventors: Jonas Karlsson, Bjorn Gudmundson, Ulf Forssen, Sara Mazur
  • Patent number: 6157343
    Abstract: A method and a system for calibrating the reception and transmission of an antenna array for use in a cellular communication system is disclosed. The calibration of the reception of the antenna array is performed by injecting a single calibration signal into each of a number of receiving antenna sections, in parallel. The signals are collected after having passed receiving components that might have distorted the phase and amplitude. Correction factors are generated and applied to received signals. The calibration of the transmission of the antenna array is performed in a similar way. A single calibration signal is generated and injected into each of a number of transmitting antenna sections, one at a time. The signals are collected, one at a time, after having passed transmitting components that might have distorted the phase and amplitude. Correction factors are generated and applied to signals that are to be transmitted.
    Type: Grant
    Filed: April 21, 1997
    Date of Patent: December 5, 2000
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Soren Andersson, Ulf Forssen, Fredrik Bengt Ovesjo, Sven Oscar Petersson
  • Patent number: 6021329
    Abstract: A method, and associated apparatus, for determining cell relationships in a radio communication system, such as a cellular communication system. The cell relationships describe how communications in a cell are disturbed by communications in other cells. The cell relationships are used, for example, in frequency planning procedures and procedures by which to determine neighbor cell lists.
    Type: Grant
    Filed: May 1, 1997
    Date of Patent: February 1, 2000
    Assignee: Telefonaktie Bolaget LM Ericsson (publ)
    Inventors: Carl Fredric Ulf Kornestedt, Ulf Forssen, Soren Andersson
  • Patent number: 5924020
    Abstract: An antenna assembly, and an associated method, which exhibits a selected the antenna beam configuration. The direction of a primary lobe and of a null is selected to improve the signal-to-noise and signal-to-interference ratios of communication signals transmitted between two communication stations. When implemented to form a portion of a base station of a cellular communication system, the traffic capacity of the communication system can be increased and the infrastructure costs of the system can be reduced.
    Type: Grant
    Filed: December 15, 1995
    Date of Patent: July 13, 1999
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventors: Ulf Forssen, Soren Anderson, Bjorn Johannisson
  • Patent number: 5848358
    Abstract: An intra-cell handover method in a cellular communication system which utilizes spatial information from an antenna array is disclosed. The spatial information is measured with the antenna array. A determination is then made on whether an intra-cell handover is desirable for a mobile station based upon said measured spatial information. The mobile station is then handed over from a first channel to a second channel when desirable and spatial filters in transceivers for mobile stations using the first and second channels are computed based on the spatial information.
    Type: Grant
    Filed: October 31, 1996
    Date of Patent: December 8, 1998
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Ulf Forssen, Bjorn Gudmundsson
  • Patent number: 5615409
    Abstract: A method and apparatus for transmitting and receiving signals in a base station with an antenna array in a cellular communication system. The available communication channels are divided into a plurality of classes. The base station transmits signals to the mobile station in a first class of channels in a wide antenna lobe. The position of a mobile station can then be determined from signals received at the base station from the mobile station. After the position of the mobile station has been determined, the base station can transmit signals to and receive signals from the mobile station in a second class channel with a narrow antenna lobe.
    Type: Grant
    Filed: September 25, 1995
    Date of Patent: March 25, 1997
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Ulf Forssen, Bjorn Gudmundson
  • Patent number: 5566209
    Abstract: A transceiver for improving the spectral efficiency and the capacity of cellular communication systems is disclosed. The transceiver uses an antenna array for communicating in a cellular communication system with a plurality of mobile stations. In addition, the transceiver contains a spatial filter connected to an antenna array wherein the spatial filter has as many outputs as there are array elements and as many inputs as there are spatial channels. A splitter then splits data to be transmitted to each mobile station into a number of parallel data streams, the number of parallel data streams corresponds with the number of spatial channels in the system, wherein the data streams, are delayed based upon uplink measurements. Finally, power allocators are provided for allocating transmission power to each possible channel based upon long-term SNR measurements on the uplink.
    Type: Grant
    Filed: February 10, 1994
    Date of Patent: October 15, 1996
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Ulf Forssen, Bjorn Gudmundson