Radio transmission control method, radio receiver apparatus, and radio transmitter apparatus

• US 8,385,295 B2
• Filed: 02/09/2012
• Issued: 02/26/2013
• Est. Priority Date: 08/04/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hara, Yoshitaka, Taira, Akinori, Otsuki, Tomoaki, Suto, Kenji
• Primary Examiner(s): Patel, Nimesh
• Application Number:
  US13/369,352
• Publication Number:
  US 20120134437A1
• Time in Patent Office: 383 Days
• Field of Search: 455/454, 455/562.1, 455/560.1, 455/575.7, 455/553.1, 455/95, 455/450, 455/501, 375/267, 375/299, 370/334, 370/267, 370/347, 370/610, 370/342
• US Class Current: 370/334
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Conventionally, if the number of transmission antennas is greater than that of reception antennas, different signals simultaneously transmitted from the transmission antennas cannot be separated from one another at the receiving end, resulting in a significant degradation of received-signal quality. A transmitter and a receiver each have a plurality of antennas. The transmitter transmits a pilot signal. The receiver receives the pilot signal, calculates transmission-related information corresponding to the pilot signal, selects, based on this calculated information, a transmission signal to be used by the transmitter, and notifies the transmitter of the selected signal. The transmitter selects, from the informed transmission signal, transmission antennas and uses the selected antennas to transmit information signals, so that a signal separation can be easily performed at the receiving end.

Claims

1. A radio communication method by a radio communication system in which output signals are generated from a plurality of information signals and then transmitted respectively at a plurality of different frequencies to a system of a communication partner from N antennas, the method comprising:

receiving control information by a control signal which is transmitted by the system of the communication partner; and

transmitting transmission signals respectively at the plurality of frequencies from the N antennas based on the received control information, the transmission signals each being generated based on a first operation result, which is obtained by multiplying a first information signal by a first N-dimensional weight vector, and a second operation result, which is obtained by multiplying a second information signal by a second N-dimensional weight vector, wherein

the control information includes weight-related information representing a set of the first N-dimensional weight vector and the second N-dimensional weight vector,

the first information signal and the second information signal include a set of signals modulated and encoded individually, and

the weight-related information is common to all of the plurality of frequencies used for signal transmission from the radio communication system to the system of the communication partner.

2. A radio communication system in which output signals are generated from a plurality of information signals and then transmitted respectively at a plurality of different frequencies to a system of a communication partner from N antennas, comprising:

reception means for receiving control information by a control signal which is transmitted by the system of the communication partner; and

transmission means for transmitting transmission signals respectively at the plurality of frequencies from the N antennas based on the received control information, the transmission signals each being generated based on a first operation result, which is obtained by multiplying a first information signal by a first N-dimensional weight vector, and a second operation result, which is obtained by multiplying a second information signal by a second N-dimensional weight vector, wherein

the control information includes weight-related information representing a set of the first N-dimensional weight vector and the second N-dimensional weight vector,

the first information signal and the second information signal include a set of signals modulated and encoded individually, and

the weight-related information is common to all of the plurality of frequencies used for signal transmission from the radio communication system to the system of the communication partner.