Methods and apparatus for transmitting information between a basestation and multiple mobile stations
View Patent ↗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.
1. A communications apparatus, comprising:
a source of data;
a transmitter circuit coupled to the source of data for generating a plurality of data signals each data signal including the same data, the plurality of data signals including a first data signal and a second data signal the first and second data signals differing from one another as a function of time by at least one of a phase and an amplitude, the transmitter circuit including means for independently varying the phase of at least one of the first and second data signals as a function of time;
a plurality of antennas coupled to said transmitter circuit to receive and transmit said data signals in parallel, each antenna receiving and transmitting one of said data signals;
a receiver for receiving communications channel condition information from a plurality of mobile stations regarding the condition of a communications channel associated with individual ones of said plurality of mobile stations;
means for scheduling transmission of data to individual mobile stations as a function of the received communications channel condition information wherein the means for scheduling includes a scheduling routine which gives preferential treatment to the scheduling of data transmissions to mobile stations with good communications channels as compared to mobile stations with poorer communications channels; and
means for determining the rate at which data should be transmitted in said first and second data signals as a function of the communications channel information.
2. A base station, the base station comprising:
i) a receiver for receiving communications channel condition information regarding the condition of a first communications channel existing between the base station and a mobile station and information regarding the condition of additional communications channels existing between the base station and a plurality of additional mobile stations;
ii) means for determining the rate at which data is transmitted to said mobile station as a function of the channel condition information;
iii) means for determining the order in which the base station is to transmit data to different mobile stations as a function of said communication channel conditionn information and said additional communications channel condition information; and
iv) means for introducing signal variations into signals transmitted to the mobile stations so that the mobile stations will detect fluctuations in received signal power.
3. The base station of claim 2 , wherein signals transmitted to the mobile stations are OFDM signals.
4. The base station of claim 3 , wherein said: means for determining the order in which the base station is to transmit data to different mobile stations as a function of said communication channel condition information and said additional communications channel condition information includes a scheduler routine stored in a memory.
5. The base station of claim 2 , further comprising: includes:
at least a first and second antenna for broadcasting first and second signals including the same data to one of said mobile stations, the first and second signals having different phases.
6. A communications system, comprising:
a mobile station;
a plurality of additional mobile stations; and
a base station, the base station including:
i) a receiver for receiving communications channel condition information regarding the condition of a first communications channel existing between the base station and the mobile station and for receiving additional communications channel condition information regarding the condition of additional communications channels existing between the base station and said additional mobile stations;
ii) means for determining the rate at which data is transmitted to said mobile station as a function of the channel condition information;
iii) means for determining the order in which the base station is to transmit data to different mobile stations as a function of said communication channel condition information and said additional communications channel condition information; and
iv) at least a first and second antenna for broadcasting first and second signals including the same data to one of said mobile stations the first and second signals having different amplitudes.
7. A communications system, comprising:
a mobile station;
a plurality of additional mobile stations; and
a base station, the base station including:
i) a receiver for receiving communications channel condition information regarding the condition of a first communications channel existing between the base station and the mobile station and for receiving additional communications channel condition information regarding the condition of additional communications channels existing between the base station and said additional mobile stations;
ii) means for determining the rate at which data is transmitted to said mobile station as a function of the channel condition information;
iii) means for determining the order in which the base station is to transmit data to different mobile stations as a function of said communication channel condition information and said additional communications channel condition information; and
iv) means for introducing signal variations into signals transmitted to the mobile stations so that the mobile stations will detect fluctuations in received signal power.
8. The communication system of claim 7 , wherein said means for introducng signal variatons into signals includes a plurality of antennas for transmitting the same data in parallel.