REDUCED INTERFRAME SPACING IN A WIRELESS LAN RECEIVER

• US 20070217378A1
• Filed: 11/10/2006
• Published: 09/20/2007
• Est. Priority Date: 11/11/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: KONDYLIS, GEORGE, FISCHER, MATTHEW, MOORTI, RAJENDRA
• Granted Patent: US 8,116,290 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A receiver in a wireless local area network capable of receiving and processing plurality of frames that are separated by a reduced interframe spacing interval. . Upon receiving a frame, the receiver determines whether the received frame is using Reduced Interframe Spacing intervals. When the received frame includes a RIFS indicator, acknowledgment of the received frame is suppressed, and subsequent frames of the plurality of frames are received at a RIFS interval.

Claims

1. A method for receiving a plurality of frames in a Wireless Local Area Network comprises:

receiving a first and a second frame of the plurality of frames;

determining whether the first and the second received frames are separated by a reduced interframe spacing (“

RIFS”

)interval; and

when the first and the second received frames are separated by a RIFS interval,

suppressing acknowledgment of received frames of the plurality of frames; and

receiving subsequent frames of the plurality of frames at a RIFS interval.

2. The method of claim 1 wherein determining whether the first and the second received frames are separated by a RIFS interval comprises:

determining whether the first received frame includes a RIFS indicator.

3. The method of claim 1 wherein determining whether the first and the second received frames are separated by a RIFS interval comprises:

sensing the second frame within a RIFS interval duration.

4. The method of claim 1 further comprises:

sending, in response to the received plurality of frames, a block acknowledgment.

5. The method of claim 1 wherein receiving the subsequent frames of the plurality of frames comprises:

for each of the subsequent frames;

sensing for a carrier of the received subsequent frame while sustaining a receiver setup for a predetermined delay interval, wherein the receiver setup relates to the received frame;

when a carrier is sensed, processing the received subsequent frame with the receiver setup; and

when a carrier is not sensed, tearing down the receiver setup.

6. The method of claim 5 wherein when the carrier is sensed, finely adjusting the receiver setup including channel estimation and fine frequency acquisition.

7. The method of claim 1 further comprises:

processing a data portion of the received frame in a back-end process while receiving the subsequent frame.

8. The method of claim 7 further comprises:

processing a preamble portion of the received subsequent frame in a front-end process while processing the data portion of the received frame in the back-end process, wherein the processing of the preamble portion and of the data portion occur at least partially in parallel.

9. The method of claim 1 wherein the plurality of frames include a frame fragment.

10. A method for receiving a plurality of frames in a Wireless Local Area Network, each frame of the plurality of frames including a preamble portion and a data portion, the method comprises:

receiving a frame of the plurality of frames;

processing the preamble portion of the received frame in a front-end process including carrier sensing and configuring a receiver setup in a physical layer, wherein the receiver setup relates to the preamble portion;

receiving a subsequent frame of the plurality of frames; and

determining whether there is a reduced interframe spacing (“

RIFS”

) interval separating the received subsequent frame and the received frame;

when there is a RIFS interval, processing the data portion of the received subsequent frame in a back-end process using the receiver setup; and

when the interval is not an RIFS interval, tearing down the receiver setup.

11. The method of claim 10 wherein determining whether there is a RIFS interval comprises:

sensing for a carrier of the received subsequent frame while sustaining the receiver setup;

when a carrier is sensed, the RIFS interval is present.

12. The method of claim 10 wherein when the carrier is sensed, finely adjusting the receiver setup including channel estimation and fine frequency acquisition based upon a portion of the preamble of the subsequent received frame.

13. The method of claim 10 further comprises:

processing a data portion of the received frame in a back-end process while receiving the subsequent frame.

14. The method of claim 10 wherein the plurality of frames includes a frame fragment.

15. Apparatus for receiving a plurality of frames in a Wireless Local Area Network, each frame of the plurality of frames including a preamble portion and a data portion, comprising:

a radio front end operable to produce an inbound continuous waveform signal, the radio front end including circuitry operable to receive an radio frequency (“

RF”

) signal, downconvert the received RF signal to one of a baseband or intermediate frequency signal, filtration circuitry to filter noise and unwanted frequency components, and amplification circuitry to amplify the RF and downconverted signals;

analog-to-digital conversion circuitry for converting the inbound continuous waveform signal from an analog domain to an inbound digital signal; and

wherein the apparatus functions to;

receive a frame of the plurality of frames;

determine whether to process the received frame in a Reduced InterFrame Spacing (“

RIFS”

) receive mode; and

when in the RIFS receive mode,

process the preamble portion of the received frame in a front-end process including carrier sensing and configuring a receiver setup of a physical (“

PHY”

) layer;

process the data portion of the received frame in a back-end process after processing the preamble portion;

receive a subsequent frame of the plurality of frames within a RIFS interval;

process the data portion of the received subsequent frame in a back-end process using the receiver setup without tearing down the receiver setup of the PHY layer.

16. The apparatus of claim 15 wherein when the carrier of the subsequent frame is sensed, finely adjusting the receive station setup including adjusting channel estimation and fine frequency acquisition based upon a portion of the preamble of the subsequent received frame.

17. The apparatus of claim 15 further functions to process the data portion of the received frame in the back-end process while receiving the subsequent frame.

18. The apparatus of claim 15 wherein the plurality of frames includes a frame fragment.

19. The apparatus of claim 15 wherein determining whether the plurality of frames are transmitted in the RIFS receive mode by evaluating a RIFS indicator included with the received frame.

20. The apparatus of claim 15 wherein determining whether the plurality of frames are transmitted in the RIFS receive mode by monitoring a channel of the WLAN.

21. Apparatus for receiving a plurality of frames in a Wireless Local Area Network, each frame of the plurality of frames including a preamble portion and a data portion, the apparatus comprises:

a radio front end for producing an inbound continuous waveform signal;

analog-to-digital conversion circuitry for converting the inbound continuous waveform signal from an analog domain to an inbound digital signal;

a baseband processing module operably disposed to receive and process the inbound digital signal; and

memory operably coupled to the baseband processing module, wherein the memory stores operational instructions that cause the processing module to;

receive a frame of the plurality of frames;

determine whether to process the received frame and subsequent frames of the plurality of frames in a Reduced InterFrame Spacing (“

RIFS”

) receive mode;

when in the RIFS receive mode,

process the preamble portion of the received frame in a front-end process including carrier sensing and receiver setup, wherein the receiver setup relates to the preamble portion;

when the preamble portion is processed, process the data portion of the received frame in a back-end process;

receive a subsequent frame of the plurality of frames within a RIFS interval; and

processing the data portion of the received subsequent frame in a back-end process using the receiver setup.

22. The apparatus of claim 21 wherein when the carrier is sensed, finely adjusting the receiver setup including channel estimation and fine frequency acquisition based upon a portion of the preamble of the received subsequent frame.

23. The apparatus of claim 21 wherein processing of the data portion of the received frame in the back-end process continues while receiving the received subsequent frame.

24. The apparatus of claim 22 wherein the plurality of frames includes a frame fragment.

25. The apparatus of claim 22 wherein the receive station determines whether the plurality of frames are transmitted in the RIFS interval receive mode by a RIFS indicator included with the received frame.

26. The apparatus of claim 22 wherein the receive station determines whether the plurality of frames are transmitted in the RIFS interval receive mode by monitoring a channel of the WLAN.