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<ul><li>Power Save Mechanisms Supported by IEEE 802.11 Protocol </li></ul><ul><li>Tutorial - 2 </li></ul><ul><li>Shashank ...
U-APSD Mechanism <ul><li>AP transmits traffic only when it receives trigger enabled frame from STA. </li></ul><ul><ul><li>...
U-APSD Power Save Mechanism <ul><li>Whenever AP receives trigger enabled frame from STA, AP transmits ‘n’ number of frames...
SM Mechanism <ul><li>SM Powersave Mechanism is advertised in  the HT capability IE of APs Beacon. </li></ul><ul><li>SM pow...
Dynamic SM Power Save Mechanism RTS CTS QoS Data Basic Association Procedure  <ul><li>In this PS mode, STA is always awake...
Static SM Power Save Mechanism SM Power Save HT Action Frame QoS Data Basic Association Procedure  <ul><li>In this PS mode...
PSMP Power Save Mechanism PSMP Power Save Frame QoS Data Basic Association Procedure  <ul><li>In this PS mode, AP transmit...
<ul><li>? </li></ul><ul><li>For any queries mail me at </li></ul><ul><li>[email_address] </li></ul>
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Power Save Mechanismin80211 Protocol Part2

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This presentation represents the basic pictorial functionality of various power save mechanisms supported in IEEE 802.11 protocol.

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Transcript of "Power Save Mechanismin80211 Protocol Part2"

  1. 1. <ul><li>Power Save Mechanisms Supported by IEEE 802.11 Protocol </li></ul><ul><li>Tutorial - 2 </li></ul><ul><li>Shashank Tadakamadla </li></ul>
  2. 2. U-APSD Mechanism <ul><li>AP transmits traffic only when it receives trigger enabled frame from STA. </li></ul><ul><ul><li>Trigger enabled frame will be negotiated in (Re)Association Request frame. </li></ul></ul><ul><ul><li>Trigger enabled frame can also be updated using ADDTS request frame per AC. </li></ul></ul>
  3. 3. U-APSD Power Save Mechanism <ul><li>Whenever AP receives trigger enabled frame from STA, AP transmits ‘n’ number of frames. Where ‘n’ is the number of frames negotiated at the time of association. ‘n’ can be all, 2, 4 & 6 frames. </li></ul><ul><li>Once ‘n’ number of frames are transmitted by AP, AP sets EOSP=1 in the last QoS frame in that Service period. Which indicates that client shall go to sleep after receiving last frame. </li></ul><ul><li>Client wakes up at regular intervals of Service Interval. Which is also negotiated at the time of association. SI can be updated using ADDTS request frame. </li></ul><ul><li>If the More Data field is set in the last data frame transmitted by AP, STA wakes up after Service Interval and retrieves data for a SP as negotiated. </li></ul><ul><li>If traffic buffered at AP is non-AC, then PS mode STAs retrive data using Legacy Methods. </li></ul>QoS Null/Data Frame Acknowledgement QoS Data Basic Association Procedure 1 2 3 QoSData Acknowledgement Acknowledgement 4 5 Access Point Station
  4. 4. SM Mechanism <ul><li>SM Powersave Mechanism is advertised in the HT capability IE of APs Beacon. </li></ul><ul><li>SM powersave mechanisms are of two types: </li></ul><ul><ul><li>Dynamic SM </li></ul></ul><ul><ul><ul><li>A STA enables its multiple receive chains only when it receives start of sequence frames. Basically an RTS/CTS frames can this used for this purpose. </li></ul></ul></ul><ul><ul><li>Static SM </li></ul></ul><ul><ul><ul><li>A STA enables its multiple receive chains only when it receives SM Power Save HT action frame from AP to client. </li></ul></ul></ul>
  5. 5. Dynamic SM Power Save Mechanism RTS CTS QoS Data Basic Association Procedure <ul><li>In this PS mode, STA is always awake but with its single chain active. </li></ul><ul><li>Whenever a frame is to be transmitted by AP, AP transmits an RTS/CTS frames. When an RTS frame is received by STA, all the chains shall be active for the duration mentioned in the RTS/CTS frames respectively after the SIFS period. </li></ul><ul><li>After receiving the frame, STA is active only with single chain until it receives either RTS/CTS frame. </li></ul><ul><li>Its up to vendor to decide which frame should be selected as start of data delivery to STA. Usually, RTS / CTS frames are used as start of data delivery. </li></ul>Acknowledgement . . . Access Point Station
  6. 6. Static SM Power Save Mechanism SM Power Save HT Action Frame QoS Data Basic Association Procedure <ul><li>In this PS mode, STA is always awake with single active chain. </li></ul><ul><li>Whenever a frame is to be transmitted by AP, AP transmits an SM Action frame. When an SM action frame is received by STA, all the chains shall be active and STA starts receiving data until More Data bit is equal to 0. </li></ul><ul><li>After receiving the frame, STA is active only with single chain. </li></ul>Acknowledgement . . . . Access Point Station
  7. 7. PSMP Power Save Mechanism PSMP Power Save Frame QoS Data Basic Association Procedure <ul><li>In this PS mode, AP transmits PSMP frame when all stations are awake in its BSS. </li></ul><ul><li>More information related to PSMP can be found in standard. </li></ul>Acknowledgement . . . . Access Point Station
  8. 8. <ul><li>? </li></ul><ul><li>For any queries mail me at </li></ul><ul><li>[email_address] </li></ul>
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