Transmission apparatus, reception apparatus, communication system, and processing method used in reception apparatus

• US 8,588,098 B2
• Filed: 11/25/2009
• Issued: 11/19/2013
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ito, Osamu
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): Hunt, Kenneth P
• Application Number:
  US13/129,954
• Publication Number:
  US 20110222429A1
• Time in Patent Office: 1,455 Days
• Field of Search: 370/252, 370/491, 370/500, 370503-520
• US Class Current: 370/252
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

The present invention relates to a transmission apparatus, a reception apparatus, a communication system, and a processing method used in the reception apparatus that are capable of reducing collisions of an Ack frame.

A transmission apparatus 100 transmits an Ack frame 200 made up of only a PLCP preamble. In a reception apparatus 300, an RF unit 320 supplies the Ack frame 200 received by an antenna 310 to a PMD unit 340. The PMD unit 340 determines a termination end of the Ack frame 200 on the basis of a signal strength of the Ack frame 200 supplied from the RF unit 320. Furthermore, the PMD unit 340 generates a timing of the termination end of the PLCP preamble of the Ack frame 200 on the basis of the PLCP preamble. A PLCP unit 350 detects the Ack frame 200 on the basis of a result in which the termination end of the Ack frame 200 has been determined using the signal strength and the timing of the termination end of the PLCP preamble generated by the PLCP preamble of the Ack frame 200.

Claims

1. A communication apparatus comprising:

a preamble generating unit operable to generate a packet signal comprising a preamble for adjusting carrier frequency error of a high-frequency signal; and

a transmitting unit operable to transmit the generated packet signal as the high-frequency signal to a receiving apparatus, wherein the receiving apparatus detects that the received packet signal is an acknowledgement frame if a timing of termination end of the received packet signal is less than a timing of termination end of the preamble.

11. The communication apparatus according to claim 1, wherein the preamble generating unit comprises a Physical Layer Convergence Protocol (PLCP) unit and a Physical Medium Dependent (PMD) unit.

12. The communication apparatus according to claim 11, wherein the PLCP unit is operable to generate the preamble and the PMD unit is operable to set a transmission level for the transmitting unit to transmit the preamble.

13. The communication apparatus according to claim 1, wherein the transmitting unit is operable to transmit the high-frequency signal in a frequency band of one of:

2.4 GHz band or a 5.2 GHz band.

2. A reception apparatus comprising:

a receiving unit operable to receive a packet signal comprising a preamble;

a signal strength determining unit operable to determine a timing of termination end of the packet signal on the basis of a signal strength of the packet signal received by the receiving unit;

a timing generating unit operable to detect the preamble from the received packet signal and generate a timing of termination end of the detected preamble; and

an acknowledgement frame detecting unit operable to detect that the received packet signal is an acknowledgement frame if the timing of the termination end of the received packet signal is less than the timing of the termination end of the detected preamble.

3. The reception apparatus according to claim 2, wherein the acknowledgement frame detecting unit is operable to detect that the received packet signal is the acknowledgement frame on the basis of an estimated period and the timing of the termination end of the received packet signal, wherein the estimated period is a period in which the signal strength determining unit determines the timing of the termination end of the received packet signal on the basis of the timing of the termination end of the detected preamble.

4. The reception apparatus according to claim 2, further comprising:

a decoding unit operable to decode the packet signal received by the receiving unit; and

an acknowledgement data detecting unit operable to detect that data decoded by the decoding unit is the data representing an acknowledgement.

5. The reception apparatus according to claim 2, wherein the signal strength determining unit is operable to determine the timing of the termination end of the received packet signal on the basis of the signal strength of the packet signal received by the receiving unit and a certain threshold.

6. The reception apparatus according to claim 5, wherein the signal strength determining unit is operable to determine the timing of the termination end of the received packet signal on the basis of an amount of change in the signal strength of the packet signal received by the receiving unit.

7. The reception apparatus according to claim 5, wherein the signal strength determining unit is operable to set the threshold on the basis of the signal strength of the packet signal before the packet signal is received by the receiving unit.

14. The reception apparatus according to claim 2, wherein the received packet signal is detected as the acknowledgement frame when the timing of the termination end of the received packet signal is within a period defined by a first timing threshold and a second timing threshold.

15. The reception apparatus according to claim 14, wherein the second timing threshold is larger than the first timing threshold.

16. The reception apparatus according to claim 2, wherein the acknowledgement frame detecting unit is operable to:

determine difference information by subtracting the timing of the termination end of the received packet signal from the timing of the termination end of the detected preamble; and

compare the determined difference information with a first timing threshold and a second timing threshold for the detection of the acknowledgement frame.

17. The reception apparatus according to claim 16, wherein the received packet signal is detected as the acknowledgment frame, if the determined difference information is larger than the first timing threshold and is lesser than the second timing threshold.

18. The reception apparatus according to claim 2, wherein the preamble comprises a plurality of short training symbols and a plurality of long training symbols.

19. The reception apparatus according to claim 2, wherein the timing generating unit is operable to perform amplification of the received packet signal and adjust carrier frequency error in the received packet signal.

20. The reception apparatus according to claim 2, wherein the received packet signal is detected as a data frame if the timing of the termination end of the received packet signal is not determined by the signal strength determining unit.

8. A communication system comprising:

a transmission apparatus operable to transmit a packet signal comprising a preamble; and

a reception apparatus that comprises;

a receiving unit operable to receive the packet signal transmitted from the transmission apparatus;

a signal strength determining unit operable to determine a timing of termination end of the received packet signal on the basis of a signal strength of the packet signal received by the receiving unit;

a timing generating unit operable to detect the preamble from the received packet signal and generate a timing of termination end of the detected preamble; and

an acknowledgement frame detecting unit operable to detect that the received packet signal is an acknowledgement frame if the timing of the termination end of the received packet signal is less than the timing of the termination end of the detected preamble.

9. An acknowledgement frame detection method comprising:

receiving a packet signal comprising a preamble;

determining a timing of termination end of the received packet signal on the basis of a signal strength of the received packet signal;

detecting the preamble from the received packet signal;

generating a timing of termination end of the detected preamble; and

detecting that the received packet signal is an acknowledgement frame if the timing of the termination end of the received packet signal is less than the timing of the termination end of the detected preamble.

10. The acknowledgement frame detection method according to claim 9, further comprising:

determining difference information by subtracting the timing of the termination end of the received packet signal from the timing of the termination end of the detected preamble; and

comparing the determined difference information with a first timing threshold and a second timing threshold for the detection of the acknowledgement frame, wherein the received packet signal is detected as the acknowledgment frame, if the difference information is larger than the first timing threshold and is lesser than the second timing threshold.