Gain control for reduced interframe spacing (RIFS)

• US 8,116,408 B2
• Filed: 06/16/2008
• Issued: 02/14/2012
• Est. Priority Date: 06/15/2007
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Gaikwad, Rohit V.
• Primary Examiner(s): LEE, SIU M
• Application Number:
  US12/213,179
• Publication Number:
  US 20080310559A1
• Time in Patent Office: 1,338 Days
• Field of Search: 375/340, 375/260, 375/267, 375/316, 375/345, 375/349, 375/350, 342/101, 342/98, 342/89
• US Class Current: 375/340
• CPC Class Codes: H03H 17/0294 Variable filters; Programmable filters
• CPC Class Codes: H04L 27/0002 analog front ends; means for connecting modulators, demodulators or transceivers to a transmission line duplex arrangements H04L5/143
• CPC Class Codes: H04L 7/046 using a dotting sequence

Abstract

A method and apparatus is disclosed to recover at least one information payload from a frame and/or to configure one or more reception parameters to receive a future frame to support RIFS. A physical layer device (PHY) receives at least a training sequence embedded in the frame of a transmitted communication signal using a receiver filter bandwidth corresponding to a variable filter training sequence bandwidth. The PHY determines an amount of gain necessary to recover an information payload embedded in the frame based on the recovery of the training sequence. The PHY determines an amount of gain necessary to recover an information payload embedded in the frame based on the recovery of the preamble. A previous communications receiver gain is adjusted by the difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain. The PHY adjusts the receiver filter bandwidth from the variable filter training sequence bandwidth to a variable filter information payload bandwidth. The PHY recovers the at least one information payload embedded in frame using the variable filter information payload bandwidth. The PHY adjusts the receiver filter bandwidth from the information payload bandwidth to the variable filter training sequence bandwidth to receive the future frame.

Claims

1. A method for recovering an information payload embedded in one or more communication signals by a communications receiver, the one or more communication signals including a plurality of frames separated by a corresponding interframe spacer from among a plurality of interframe spacers, comprising:

(A) recovering a training sequence embedded in a frame from among the plurality of frames using a variable filter training sequence bandwidth;

(B) adjusting a reception parameter based on a previous reception parameter;

(C) adjusting a receiver filter bandwidth from the variable filter training sequence bandwidth to a variable filter information payload bandwidth when the reception parameter has substantially settled to a steady-state condition;

(D) recovering an information payload embedded in the frame using the variable filter information payload bandwidth before a duration of the corresponding interframe spacer lapses; and

(E) adjusting the receiver filter bandwidth from the variable filter information payload bandwidth to the variable filter training sequence bandwidth.

2. The method of claim 1, wherein step (A) comprises:

(A)(i) recovering the training sequence embedded in the frame in accordance with at least one selected from a group consisting of;

a known single stream communications standard; and

a known multiple stream communications standard.

3. The method of claim 2, wherein step (A)(i) comprises:

(A)(i)(1) recovering the training sequence embedded in the frame in accordance with at least one selected from a group consisting of;

an Institute of Electrical and Electronics Engineers (IEEE) 802.11a™

standard;

an IEEE 802.11b™

standard;

an IEEE 802.11g™

standard; and

an IEEE 802.11n™

standard.

4. The method of claim 1, wherein step (A) comprises:

(A)(i) recovering a preamble embedded in the frame using the variable filter training sequence bandwidth.

5. The method of claim 4, wherein step (A)(i) comprises:

(A)(i)(1) recovering at least one selected from a group consisting of a single stream preamble and a multiple stream preamble embedded in the frame using the variable filter training sequence bandwidth.

6. The method of claim 4, wherein step (A)(i) comprises:

(A)(i)(1) recovering the preamble embedded in the frame in accordance with at least one selected from a group consisting of;

a known single stream communications standard; and

a known multiple stream communications standard.

7. The method of claim 1, wherein step (A)(i)(1) comprises:

(A)(i)(1)(a) recovering the preamble embedded in the frame in accordance with at least one selected from a group consisting of;

an Institute of Electrical and Electronics Engineers (IEEE) 802.11a™

standard;

an IEEE 802.11b™

standard;

an IEEE 802.11g™

standard; and

an IEEE 802.11n™

standard.

8. The method of claim 1, wherein step (A) comprises:

(A)(i) recovering at least one of a single stream training sequence and a multiple stream training sequence embedded in the frame using the variable filter training sequence bandwidth.

9. The method of claim 1, wherein step (B) comprises:

(B)(i) adjusting a communications receiver gain based on a previous communications receiver gain.

10. The method of claim 9, wherein step (B)(i) comprises:

(B)(i)(1) determining an amount of gain necessary to recover the information payload based on the training sequence;

(B)(i)(2) determining a difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain; and

(B)(i)(3) adjusting the previous communications receiver gain by the difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain.

11. The method of claim 9, wherein step (C) comprises:

(C)(i) adjusting a receiver filter bandwidth from the variable filter training sequence bandwidth to a variable filter information payload bandwidth when the communications receiver gain has substantially settled to the steady-state condition.

12. The method of claim 1, wherein step (D) comprises:

(D)(i) recovering the payload embedded in the frame in accordance with at least one selected from a group consisting of;

a known single stream communications standard; and

a known multiple stream communications standard.

13. The method of claim 1, wherein step (D)(i) comprises:

(D)(i)(1) recovering the payload embedded in the frame in accordance with at least one selected from a group consisting of;

an Institute of Electrical and Electronics Engineers (IEEE) 802.11a™

standard;

an IEEE 802.11b™

standard;

an IEEE 802.11g™

standard; and

an IEEE 802.11n™

standard.

14. The method of claim 1, wherein step (D) comprises:

(D)(i) recovering the payload embedded in the frame substantially before a duration of a reduced interframe spacer (RIFS) lapses.

15. A communications receiver for recovering an information payload embedded in one or more communication signals, the one or more communication signals including a plurality of frames separated by a corresponding interframe spacer from among a plurality of interframe spacers, comprising:

a radio receiver configured to operate upon the one or more communication signals using a reception parameter to recover a frame from among the plurality of frames;

a physical layer interface (PHY) receiver filter configured to operate upon the frame using a PHY receiver filter bandwidth;

one or more baseband processing modules configured to recover a training sequence and an information payload embedded in the frame before a duration of the corresponding interframe spacer lapses,

wherein the one or more baseband processing modules are configured to adjust the reception parameter based on a previous reception parameter before recovering the information payload, and

wherein the PHY receiver filter bandwidth is configurable to be adjusted to a variable filter training sequence bandwidth before recovering the training sequence and to be adjusted to a variable filter information payload bandwidth before recovering the information payload.

16. The communications receiver of claim 15, wherein the one or more baseband processing modules are further configured to recover the training sequence in accordance with at least one selected from a group consisting of:

a known single stream communications standard; and

a known multiple stream communications standard.

17. The communications receiver of claim 16, wherein the one or more baseband processing modules are further configured to recover the training sequence in accordance with at least one selected from a group consisting of:

an Institute of Electrical and Electronics Engineers (IEEE) 802.11a™

standard;

an IEEE 802.11b™

standard;

an IEEE 802.11g™

standard; and

an IEEE 802.11n™

standard.

18. The communications receiver of claim 15, wherein the training sequence includes a preamble.

19. The communications receiver of claim 18, wherein the preamble includes at least one selected from a group consisting of:

a single stream preamble; and

a multiple stream preamble.

20. The communications receiver of claim 15, wherein the reception parameter includes a communications receiver gain.

21. The communications receiver of claim 20, wherein the radio receiver is further configured to amplify the frame based on the communications receiver gain.

22. The communications receiver of claim 20, wherein the one or more baseband processing modules are configured to adjust the communications receiver gain by determining an amount of gain necessary to recover the information payload based on the training sequence, to determine a difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain, and to adjust the previous communications receiver gain by the difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain.

23. The communications receiver of claim 20, wherein the PHY receiver filter bandwidth is further configurable to be adjusted when the communications receiver gain has substantially settled to a steady-state condition.

24. The communications receiver of claim 15, wherein the one or more baseband processing modules are further configured to recover the information payload in accordance with at least one selected from a group consisting of:

a known single stream communications standard; and

a known multiple stream communications standard.

25. The communications receiver of claim 15, wherein the one or more baseband processing modules are further configured to recover the information payload more frames in accordance with at least one selected from a group consisting of:

an Institute of Electrical and Electronics Engineers (IEEE) 802.11a™

standard;

an IEEE 802.11b™

standard;

an IEEE 802.11g™

standard; and

an IEEE 802.11n™

standard.

26. The communications receiver of claim 15, wherein the one or more baseband processing modules are further configured to recover the training sequence embedded and the information payload substantially before a duration of a reduced interframe spacer (RIFS) lapses.

27. The communications receiver of claim 15, wherein the radio receiver comprises:

a radio receiver filter configured to operate upon the frame using a radio receiver filter bandwidth,

wherein the radio receiver filter bandwidth is configurable to be adjusted to the variable filter training sequence bandwidth before recovering the training sequence and to be adjusted to the variable filter information payload bandwidth before recovering the information payload.