Radio communication system, a transmitter and a receiver

• US 7,929,922 B2
• Filed: 10/31/2007
• Issued: 04/19/2011
• Est. Priority Date: 02/16/1999
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kubo, Hiroshi
• Primary Examiner(s): Nguyen; Tu X
• Application Number:
  US11/931,990
• Publication Number:
  US 20080064428A1
• Time in Patent Office: 1,266 Days
• Field of Search: 455/101, 455/102, 455/103, 455/73, 455/91, 455/560, 455/562.1, 455/115.2, 455/403, 455/115.1, 455/105, 455/110, 455/550.1, 455/114.3, 455/115.3, 455/127.2, 455/69, 455/522
• US Class Current: 455/101
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0667 of delayed versions of same signal using space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16
• CPC Class Codes: H04L 1/0618 Space-time coding

Abstract

In a transmitter 2A, after an output level of a modulated signal is regulated by a first gain regulator 5A, the signal is transmitted from a first antenna 8A without delay, and after the modulated signal is delayed by a delay unit 6A and an output level of the delay output is regulated by a second gain regulator 7A, this signal is transmitted from a second antenna 9A. Similarly, in a transmitter 2B, after an output level of a modulated signal is regulated by a first gain regulator 5B, the signal is transmitted from a first antenna 8B without delay, and after the modulated signal is delayed by a delay unit 6B and an output level of the delay output is regulated by a second gain regulator 7B, this signal is transmitted from a second antenna 9B. A receiver 3 receives the transmitted signals from the four antennas 8A, 8B, 9A and 9B via an antenna 10, and executes a demodulation process.

Claims

1. A radio communication system comprising:

a plurality of transmitters each having at least one antenna for transmitting identical signals with the same frequency band; and

a receiver for receiving said signals,

wherein said signals supplied to the antennas are obtained by differently delaying modulated signals and carrying out weighting synthesization on the delayed and modulated signals, and

wherein at least one of a delay amount and a weighting factor in each of said transmitters is set to a value different from the other transmitters.

2. The radio communication system according to claim 1, wherein said receiver comprises an equalizer for demodulating a signal transmitted from at least one antenna in each of said transmitters.

3. A radio communication system comprising:

a plurality of transmitters, each having a plurality of antennas for transmitting identical signals with the same frequency band; and

a receiver for receiving said signals,

wherein said signals supplied to said plurality of antennas are obtained by differently delaying modulated signals and carrying out amplitude regulation on the delayed and modulated signals, and

wherein at least one of a delay amount and a value of amplitude regulation is set to different values in each of said transmitters.

4. The radio communication system according to claim 3, wherein said receiver comprises an equalizer for demodulating signals transmitted from said plurality of antennas.

5. A transmitter characterized in that in the case where a plurality of transmitters transmit same signals with same frequency band, at least one antenna is provided, signals which are supplied to respective antennas are signals which are obtained by differently delaying modulated signals and carrying out weighting synthesization on the delayed and modulated signals, and at least one of a delay amount and a weighting factor is set to a value different from the other transmitters.