Radio communication device and transmitting power control method

• US 6,512,917 B1
• Filed: 03/16/2000
• Issued: 01/28/2003
• Est. Priority Date: 06/29/1998
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hiramatsu, Katsuhiko
• Primary Examiner(s): MAUNG, NAY AUNG
• Application Number:
  US09/486,106
• Time in Patent Office: 1,048 Days
• Field of Search: 455/63, 455/67.1, 455/67.3, 455/68, 455/69, 455/133, 455/134, 455/135, 455/277.1, 455/277.2, 455/422, 455/522, 455/562, 342/378, 342/380-384
• US Class Current: 455/69
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

An AAA receiving circuit 105 calculates reception weight of signals received by adaptive array antennas 101, and a direction of arrival estimating circuit 106 estimates a direction of arrival of the received signals. A demodulating circuit demodulates the received signals to separate transmission power control information. A radiation pattern calculating circuit 108 calculates directional gains based on the reception weight and the arrival direction of the received signals. A gain controlling circuit 109 calculates a correction value based on the directional gains and transmission power control information, and controls a gain of a transmission power amplifier. A transmission weight calculating circuit calculates transmission weight based on the reception weight and the correction value. This makes it possible to control transmission power such that reception power of each communication counterpart becomes constant, and to improve communication quality and an increase in the number of containable users in a system wherein directivity is sequentially changed in accordance with the positions of the communication counterparts or a propagation environment.

Claims

1. A radio communication apparatus comprising:

an array antenna for forming directivity by a plurality of antenna elements;

directional gain calculating means for calculating directional gains of received signals from said array antenna based on a direction of arrival and reception weight;

transmission gain controlling means for calculating a correction value of transmission weight from said directional gains, and for controlling a gain of a transmission power amplifier based on transmission power control information included in said correction value and said received signals; and

transmission weight controlling means for controlling transmission weight based on said reception weight and said correction value.

2. The radio communication apparatus according to claim 1, wherein said transmission gain controlling means calculates the correction value of transmission weight such that the directional gains become constant.

3. The radio communication apparatus according to claim 1, wherein said transmission gain controlling means calculates the correction value of transmission weight such that each directional gain is equal to a product of the previous directional gain and transmission power control information included in the received signals.

4. The radio communication apparatus according to claim 1, wherein the directional gain calculating means calculates each directional gain of each signal transmitted from a plurality of communication counterparts, said transmission gain controlling means calculates the correction value of transmission weight such that each directional gain is equal to a product of the previous directional gain and transmission power control information included in the received signals, said transmission gain controlling means controls the gain of the transmission power amplifier uniformly with respect to all communication counterparts, and said transmission weight controlling means controls the transmission weight for each communication counterpart based on said reception weight and said correction value.

5. The radio communication apparatus according to claim 4, further comprising input power measuring means for combining transmitted signals to the plurality of communication counterparts, and for measuring input power of the transmission power amplifier from the combined transmission signal, wherein said transmission gain controlling means controls the correction value of transmission weight of the transmitted signal to each communication counterpart and the gain of the transmission power amplifier such that the input power falls within a given range.

6. A transmission power controlling method comprising the steps of:

calculating directional gains of received signals from an array antenna, which forms directivity using a plurality of antenna elements based on a direction of arrival and reception weight;

controlling a gain of a transmission power amplifier based on transmission power control information included in the calculated directional gains and said received signals; and

controlling transmission weight based on said reception weight and said directional gains.

7. The transmission power controlling method according to claim 6, wherein said transmission weight is controlled such that the directional gains become constant.

8. The transmission power controlling method according to claim 6, wherein said transmission weight is controlled such that each directional gain is equal to a product of the previous directional gain and transmission power control information included in the received signals.

9. The transmission power controlling method according to claim 6, wherein a directional measurement area is divided to predetermined segments in the arrival direction of the received signals, and an average value of the directional gains measured in the divided directional measurement areas is used in gain control of the transmission power amplifier and transmission weight control.

10. A transmission power controlling method comprising the steps of:

calculating a directional gain of each signal, which has been transmitted from a plurality of communication counterparts and which has been received by an array antenna, which forms directivity using a plurality of antenna elements, based on a direction of arrival and a reception weight;

controlling transmission weight such that each directional gain is equal to a product of the previous directional gain and transmission power control information included in the received signals; and

controlling a gain of a transmission power amplifier based on said reception weight and said directional gains.

11. The transmission power controlling method according to claim 10, further comprising the steps of:

combining transmitted signals to the plurality of communication counterparts;

measuring input power of the transmission power amplifier from combined transmitted signals; and

controlling the transmission weight of the transmitted signals to the respective communication counterparts and the gain of the transmission power amplifier such that the input power falls within a given range.

12. The transmission power controlling method according to claim 10, wherein the received signals are despread by spread codes assigned to the plurality of communication counterparts to be separated for each communication counterpart, and the directional gain of each received signal separated is calculated for each communication counterpart based on the arrival direction and the reception weight.

13. A base station apparatus comprising a radio communication apparatus, said radio communication apparatus comprising:

an array antenna for forming directivity by a plurality of antenna elements;

directional gain calculating means for calculating directional gains of received signals from said array antenna based on a direction of arrival and reception weight;

transmission gain controlling means for calculating a correction value of transmission weight from said directional gains, and for controlling a gain of a transmission power amplifier based on transmission power control information included in said correction value and said received signals; and

transmission weight controlling means for controlling transmission weight based on said reception weight and said correction value.

14. A communication terminal apparatus comprising a radio communication apparatus, said radio communication apparatus comprising:

an array antenna for forming directivity by a plurality of antenna elements;

directional gain calculating means for calculating directional gains of received signals from said array antenna based on a direction of arrival and reception weight;

transmission gain controlling means for calculating a correction value of transmission weight from said directional gains, and for controlling a gain of a transmission power amplifier based on transmission power control information included in said correction value and said received signals; and

transmission weight controlling means for controlling transmission weight based on said reception weight and said correction value.