Methods and apparatus for transmitting information between a basestation and multiple mobile stations
AssigneeFlarion Technologies, Inc.
InventorsPramod Viswanath, Rajiv Laroia, David N. C. Tse
Life of this patent
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Abstract
Methods and apparatus for scheduling mobile stations (MSs) to download data and/or to control the rate of downloading to an MS from a base station (BS) as a function of downlink channel condition information are described. Artificial channel variations, which can be measured at the MS, and feedback to a BS for scheduling purposes, are introduced through the use of two or more transmitter antennas at a BS. Each of the antennas transmits a signal at the same frequency having the same information content, e.g., modulated data. However the signals are made to differ with time in their phase and/or amplitude to introduce what appear to be channel variations to the MSs.
Claims16
A communications method for use in a communications system including a first device, a second device, and a third device, the method comprising the steps of:
- operating the first device to receive first communications channel condition information regarding the condition of a first communications channel existing between the first device and the second device and to receive second communications channel condition information regarding the condition of a second communications channel existing between the first device and the third device;
- determining, as a function of the first communications channel condition information, when to transmit data from the first device to said second device;
- and
- determining, as a function of the second communications channel condition information, when to transmit data to said third device;
- transmitting, using a plurality of N antennas, the same data to the second device, N being a positive integer greater than one, the step of transmitting including:
- transmitting from a first antenna in said plurality of N antennas a first data signal including said data;
- transmitting from a second antenna in said plurality of N antennas a second data signal including the same data as said first data signal;
- and
- varying the relative amplitudes of the first and second data signals as a function of time while maintaining the combined average transmitted power of the first and second data signals at an almost constant value over the period in time during which the relative amplitudes of the first and second data signals are varied.
A communications method for use in a communications system including a first device, a second device, and a third device, the method comprising the steps of:
- operating the first device to receive first communications channel condition information regarding the condition of a first communications channel existing between the first device and the second device and to receive second communications channel condition information regarding the condition of a second communications channel existing between the first device and the third device;
- and
- determining, as a function of the first communications channel condition information, when to transmit data from the first device to said second device;
- and
- determining, as a function of the second communications channel condition information, when to transmit data to said third device;
- transmitting, using a plurality of N antennas, the same data to the second device, N being a positive integer greater than one, the step of transmitting including:
- transmitting from a first antenna in said plurality of N antennas a first data signal including said data;
- transmitting from a second antenna in said plurality of N antennas a second data signal including the same data as said first data signal, the first and second data signals including symbols having a symbol period;
- and
- varying at least one of the relative amplitudes of the first and second data signals over time and the relative phase of the first and second data signals over time while using a fixed average amount of power over at least one symbol period to transmit the combination of the first and second data signals.
Dependencies are inferred from the claim text.