Wireless communication method

Abstract

Wireless communication arrangements including: first base station referring to beam scheduling information including identification information of a beam pattern to be used in each slot by the second base station, selecting, where identification information of the beam area to be used by the second base station in the slot assigned is coincident with the identification information of the first interference beam area received from the wireless terminal, the first data rate received from the wireless terminal, and selects, where the identification information of the beam area to be used by the second base station is not coincident with the identification information of the first interference beam area, the second data rate received from the wireless terminal; a step at which the first base station modulates data in accordance with one of the selected first data rate and second data rate, and transmits modulated data to the wireless terminal.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001]This application is a continuation application of U.S. patent application Ser. No. 11 / 677,134, filed Feb. 21, 2007, which relates to U.S. patent application Ser. No. 11 / 508,200 filed on Aug. 23, 2006. This application relates to and claims priority from Japanese Patent Application No. 2006-080897, filed on Mar. 23, 2006. The entirety of the contents and subject matter of all of the above is incorporated herein by reference.BACKGROUND OF THE INVENTION [0002]The present invention relates to a wireless communication method, and particularly to a wireless communication method in which in a wireless system to perform cellular communication, an array antenna type wireless apparatus including a plurality of antennas is used, beams are formed in time division and packet transmission is performed.[0003]Antennas used in cellular system base stations are directional antennas to form sectors, and in some antennas, an array antenna to further subdivi...

AI Technical Summary

Benefits of technology

[0022]In light of the circumstances described above, an object of the present invention is to provide a method in which under application of an inter-base-station cooperative system, to avoid the reduction of the throughput as a result of avoidance of the interference and, also in the slot in which the interference occurs, to enable communication at a suitable forward-link transmission rate. Besides, an object of the present invention is to provide a wireless communication method in which under the application of the inter-base-station cooperative system, the amount of reverse-link feedback information is decreased, and the scale of the demodulation circuit of the wireless terminal can be made small.

[0045]According to the invention, under application of an inter-base-station cooperative system, as a result of avoidance of the interference, the reduction of the throughput is avoided, and also in the slot in which the interference occurs, communication at a suitable forward-link transmission rate is enabled. Besides, a wireless communication method and a wireless communication system can be provided in which under the application of the inter-base-station cooperative system, the amount of reverse-link feedback information is decreased, and the scale of the demodulation circuit of the wireless terminal can be made small.

[0046]According to the invention, even if a variation in the interference state of each slot occurs, the communication can be performed while using the suitable data rate. Thus, the reduction of the throughput due to this can be prevented.

Problems solved by technology

However, the forward-link data rate requested by the wireless terminal is one value estimated from the common pilot signal and is a value independent of the presence / absence of the interference, in the case where the interference from the adjacent cell occurs, there occurs a possibility that the signal of the slot can not be received.

In the related art, with respect to a slot in which interference occurs, it is difficult to accurately predict the reception quality at the time when the data signal is received based on the reception quality of the pilot signal.

However, since the forward-link communication rate requested from the terminal is a single value independent of the presence / absence of the interference, there is a case where the communication can not be performed at the rate corresponding to the change in the reception quality of each slot.

Thus, a suitable throughput can not be obtained.

However, in this system, following problems occur according to the distribution of the wireless terminals.

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