Transmission apparatus, reception apparatus and digital radio communication method

• US 7,545,882 B2
• Filed: 12/13/2007
• Issued: 06/09/2009
• Est. Priority Date: 07/28/1999
• Status: Expired due to Fees

• Current Assignee: Redwood Technologies, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Murakami, Yutaka, Matsuoka, Akihiko, Takabayashi, Shinichiro, Orihashi, Masayuki
• Primary Examiner(s): DEPPE, BETSY LEE
• Application Number:
  US11/955,443
• Publication Number:
  US 20080095270A1
• Time in Patent Office: 544 Days
• Field of Search: 375/259, 375/261, 375/264, 375/271, 375/279, 375/280, 375/281, 375/284, 375/285, 375/295, 375/298, 375/302, 375/308, 332/103, 455/67.13, 455/63.1, 455/114.2, 455/102, 455/110, 370/336, 370/337, 370/345, 370/347, 370/498
• US Class Current: 375/298
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0006 by adapting the transmission format
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/206 using a pair of orthogonal carriers, e.g. quadrature carriers
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04L 27/3455 in order to facilitate carrier recovery at the receiver end, e.g. by transmitting a pilot or by using additional signal points to allow the detection of rotations

Abstract

A transmission apparatus includes a frame configuration determiner that determines a modulation scheme, from among a plurality of modulation schemes. A first symbol generator modulates a transmission signal according the modulation scheme determined by the frame configuration determiner to generate a first symbol, the first symbol being a first quadrature baseband signal. A second symbol generator modulates a pilot signal in accordance with a specific modulation scheme to generate a second symbol. A third symbol generator generates a third symbol to be inserted immediately before or immediately after the second symbol, the third symbol being different from the first symbol. On a signal space diagram, the third symbol generator arranges a signal point of the third symbol on a virtual line that links an origin with a signal point of the second symbol.

Claims

1. A transmission apparatus comprising:

a frame configuration determiner that determines a modulation scheme, from among a plurality of modulation schemes;

a first symbol generator that modulates a transmission signal according to the modulation scheme determined by the frame configuration determiner, to generate a first symbol, the first symbol being a first quadrature baseband signal; and

a second symbol generator that modulates a pilot signal in accordance with a specific modulation scheme to generate a second symbol, and

a third symbol generator that generates a third symbol to be inserted immediately before or immediately after the second symbol, the third symbol being different from the first symbol,

wherein, on a signal space diagram, the third symbol generator arranges a signal point of the third symbol on a virtual line that links an origin with a signal point of the second symbol.

2. The transmission apparatus according to claim 1, wherein the specific modulation scheme comprises BPSK modulation.

3. The transmission apparatus according to claim 1, wherein the frame configuration determiner determines an insertion interval of the second symbol based on a communication situation.

4. The transmission apparatus according to claim 1, wherein the frame configuration determiner determines the modulation scheme for the transmission signal based on channel quality information between a transmission apparatus and a reception apparatus.

5. The transmission apparatus according to claim 4, wherein the channel quality information includes at least one of transmission path information and received signal strength information.

6. A digital radio communication method of a transmission apparatus including a frame configuration determiner, a first symbol generator, a second symbol generator and a third symbol generator, the communication method comprising:

determining a modulation scheme, from among a plurality of modulation schemes by the frame configuration determiner;

modulating, by the first symbol generator, a transmission signal according to the determined modulation scheme to generate a first symbol, the first symbol being a first quadrature baseband signal;

modulating, by the second symbol generator, a pilot signal according to a specific modulation scheme to generate a second symbol;

generating, by the third symbol generator, a third symbol to be inserted immediately before or immediately after the second symbol, the third symbol being different from the first symbol; and

arranging, by the third symbol generator, on a signal space diagram, a signal point of the third symbol on a virtual line that links an origin with a signal point of the second symbol.

7. The digital radio communication method according to claim 6, the specific modulation scheme comprising BPSK modulation.

8. The digital radio communication method according to claim 6, further comprising determining an insertion interval of the second symbol based on a communication situation.

9. The digital radio communication method according to claim 6 further comprising determining the modulation scheme for the transmission signal based on channel quality information between a transmission apparatus and a reception apparatus.

10. The digital radio communication method according to claim 9, wherein the channel quality information includes at least one of transmission path information and received signal strength information.