Gain control for reduced interframe spacing (RIFS)

• US 20080310559A1
• Filed: 06/16/2008
• Published: 12/18/2008
• Est. Priority Date: 06/15/2007
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Gaikwad, Rohit V.
• Granted Patent: US 8,116,408 B2
• Time in Patent Office: Days
• 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 to recover an information payload embedded in one or more communication signals by a communications receiver, wherein the one or more communication signals include one or more frames separated by a corresponding interframe spacer from one or more interframe spacers, comprising:

(A) recovering at least a training sequence embedded in the one or more frames using a variable filter training sequence bandwidth;

(B) adjusting one or more reception parameters based on one or more previous reception parameters;

(C) adjusting a receiver filter bandwidth from the variable filter training sequence bandwidth to a variable filter information payload bandwidth when the one or more reception parameters have substantially settled to a steady-state condition;

(D) recovering an information payload embedded in the one or more frames 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 one or more frames in accordance with at least one of;

a known single stream communications standard; and

a known multiple stream communications standard.

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

(A)(i)(1) recovering the training sequence embedded in the one or more frames in accordance with at least one 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 one or more frames 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 of a single stream preamble and a multiple stream preamble embedded in the one or more frames 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 one or more frames in accordance with at least one 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 one or more frames in accordance with at least one 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 one or more frames 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 one or more frames in the one or more frames in accordance with at least one 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 one or more frames in the one or more frames in accordance with at least one 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 one or more frames in the one or more frames substantially before a duration of a reduced interframe spacer (RIFS) lapses.

15. The method of claim 1, wherein step (E) comprises:

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

16. A communications receiver to recover an information payload embedded in one or more communication signals, wherein the one or more communication signals include one or more frames separated by a corresponding interframe spacer from one or more interframe spacers, comprising:

a radio receiver including a radio receiver filter, to downconvert the one or more frames to produce one or more downconverted frames, wherein the radio receiver operated on the one or more frames based on one or more reception parameters;

a PHY receiver filter coupled to the radio receiver to produce one or more filtered downconverted frames based on the one or more downconverted frames;

one or more baseband processing modules configured to recover at least a training sequence embedded in the one or more frames and an information payload embedded in the one or more frames based on the more filtered downconverted frames before a duration of the corresponding interframe spacer lapses,

wherein the one or more baseband processing modules adjust the one or more reception parameters based on a previous one or more reception parameters before recovering the information signal embedded in the one or more frames, and

wherein a bandwidth of the radio receiver filter and a bandwidth of the PHY receiver filter is adjusted to a variable filter training sequence bandwidth before recovering the training sequence embedded in the one or more frames and a variable filter information payload bandwidth before recovering the information signal embedded in the one or more frames.

17. The communications receiver of claim 16, wherein the one or more baseband processing modules is further configured to recover the training sequence embedded in the one or more frames in accordance with at least one of:

a known single stream communications standard; and

a known multiple stream communications standard.

18. The communications receiver of claim 17, wherein the one or more baseband processing modules is further configured to recover the training sequence embedded in the one or more frames in accordance with at least one 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.

19. The communications receiver of claim 16, wherein the at least the training sequence embedded in the one or more frames includes a preamble.

20. The communications receiver of claim 19, wherein the preamble includes at least one of:

a single stream preamble; and

a multiple stream preamble.

21. The communications receiver of claim 16, wherein the one or more reception parameters includes a communications receiver gain.

22. The communications receiver of claim 21, wherein the radio receiver amplifies the one or more frames based on the communications receiver gain.

23. The communications receiver of claim 21, wherein the one or more baseband processing modules adjust the communications receiver gain by determining an amount of gain necessary to recover the information payload based on the training sequence, determining a difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain, and 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.

24. The communications receiver of claim 21, wherein at least one of the bandwidth of the radio receiver filter and the bandwidth of the PHY receiver filter is adjusted when the communications receiver gain has substantially settled to the steady-state condition.

25. The communications receiver of claim 16, wherein the one or more baseband processing modules is further configured to recover the information payload embedded in the one or more frames in accordance with at least one of:

a known single stream communications standard; and

a known multiple stream communications standard.

26. The communications receiver of claim 16, wherein the one or more baseband processing modules is further configured to recover the information payload embedded in the one or more frames in accordance with at least one 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.

27. The communications receiver of claim 16, wherein the one or more baseband processing modules recovers at least the training sequence embedded in the one or more frames and the information payload embedded in the one or more frames substantially before a duration of a reduced interframe spacer (RIFS) lapses.

28. The communications receiver of claim 16, wherein at least one of the bandwidth of the radio receiver filter and the bandwidth of the PHY receiver filter is adjusted from the variable filter information payload bandwidth to the variable filter training sequence bandwidth if substantially recovering the information payload.