Reduced interframe spacing in a wireless LAN receiver
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.
1. 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 a 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 based upon a modulation type of the plurality of frames; and
process the data portion of the received subsequent frame in the back-end process using the receiver setup based upon a previously received frame without tearing down the receiver setup of the PHY layer.
2. The apparatus of claim 1 wherein when the carrier of the subsequent frame is sensed, finely adjusting the receiver setup including adjusting channel estimation and fine frequency acquisition based upon a portion of the preamble of the subsequent received frame.
3. The apparatus of claim 1 further functions to process the data portion of the received frame in the back-end process while receiving the subsequent frame.
4. The apparatus of claim 1 wherein the plurality of frames includes a frame fragment.
5. The apparatus of claim 1 wherein the determining whether to process the received frame in the RIFS receive mode by evaluating a RIFS indicator included with the received frame.
6. The apparatus of claim 1 wherein the determining whether to process the received frame in the RIFS receive mode by monitoring a channel of the WLAN.
7. 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, wherein the RIFS interval is based upon a modulation type of the plurality of frames; and
processing the data portion of the received subsequent frame in the back-end process using the receiver setup based upon a previously received frame.
8. The apparatus of claim 7 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.
9. The apparatus of claim 7 wherein processing of the data portion of the received frame in the back-end process continues while receiving the received subsequent frame.
10. The apparatus of claim 7 wherein the plurality of frames includes a frame fragment.
11. The apparatus of claim 7 wherein the determining whether to process the received frame and subsequent frames of the plurality of frames in the RIFS receive mode is based upon a RIFS indicator included with the received frame.
12. The apparatus of claim 7 wherein the determining whether to process the received frame and subsequent frames of the plurality of frames in the RIFS receive mode is based upon monitoring a channel of the WLAN.