KR101279735B1 - Method and system for improving responsiveness in exchanging frames in a wireless local area network - Google Patents

Abstract

A method and system for improving responsiveness in exchanging management and control frames in a local area network are disclosed. The initiator sends a frame (action, management, control or data frame) to the responder. In the case of correctly receiving this frame, the responder sends a response frame to the initiator instead of sending an acknowledgment (ACK) packet directly. The responder preferably accesses the wireless medium and transmits a response frame at short inter-frame spacing (SIFS). In this way, the long delay associated with competing for transmission of a response frame by the wireless medium can be avoided, thereby significantly improving the responsiveness and timeliness of the feedback mechanism. The response frame is piggybacked on another packet or integrated with another packet.

Wireless LAN

Description

METHOD AND SYSTEM FOR IMPROVING RESPONSIVENESS IN EXCHANGING FRAMES IN A WIRELESS LOCAL AREA NETWORK}

1 is a signaling diagram of the prior art for exchanging management frames or action frames between an initiator and a responder.

2 is a signaling diagram for exchanging management frames or action frames between an initiator and a responder in accordance with the present invention.

3 and 4 illustrate an integrated media access control layer protocol data unit (A-MPDU) with an ACK policy designated as a managed medium access control (MAC) layer protocol data unit (MMPDU) according to the present invention. An example process for exchanging packets between an initiator and a responder using < RTI ID = 0.0 >

5 and 6 illustrate examples of exchanging packets between an initiator and a responder using reduced inter-frame spacing (RIFS) with an ACK policy designated as No-ACK for MMPDUs in accordance with the present invention. Representative process.

[Description of Drawings]

102, 202: Initiator 104, 204: Responder

The present invention relates to a wireless local area network (WLAN). More specifically, the present invention relates to a method and system for improving the responsiveness when exchanging management, control or data frames in a WLAN.

In an IEEE 802.11 WLAN, an access point (AP) or station (STA) uses a management frame to perform any management function. Examples of management frames are related request, related response, rerelated request, rerelated response, probe request and probe request frame.

IEEE 802.11e extends the IEEE 802.11 standard using new management frames. Some of these new management frames are called action frames. Action frames are used to perform any function such as quality of service (QoS) traffic stream setup, direct link setup, block ACK setup, and the like. Examples of action frames include an Add Traffic Stream (ADDTS) request, an ADDTS response, a Direct Link Setup (DLS) request, a DLS response, an Add Block acknowledgement (ADDBA) request, an ADDBA response, a Delete Block ACK (DELBA) request, and the like.

In general, the IEEE 802.11n extension standard has been proposed to achieve higher throughput (HT). In the IEEE 802.11n proposal, new action frames are introduced to provide transmission mode and channel information feedback. By transmission mode feedback, the receiving station informs the transmitting station of the preferred mode for the current channel condition. The specific mode selection is determined by the receiving station. The transmitting station may or may not use a particular mode, depending on its capacity. The receiving station may also refuse to provide the desired mode. Channel information feedback provides a mechanism for the transmitting station to detect the exact channel seen at the receiving station. This information may be used as part of calibration, or as direct channel feedback, for a system that assumes channel correlation. The receiving station may provide a complete channel estimate or null response. Examples of IEEE 802.11n action frames are mode requests, mode responses, multiple-input multiple-output (MIMO) channel requests, and MIMO channel response frames.

Management frames (including action frames) may be broadcast or multicast to multiple respondents (eg, via beacon frames), or alternatively specific (single) respondents (eg, ADDBA). Request, ADDBA response, mode request, mode response, MIMO channel request and MIMO channel response). In the case where official and action frames are unicast to a particular responder, the IEEE 802.11 standard requires the responder to acknowledge receipt of such frames by sending ACK packets. On the other hand, when management or action frames are broadcast or multicast to multiple responders, the IEEE 802.11 standard does not require a responder to acknowledge receipt of such frames.

1 is a signaling diagram of a prior art process 100 for exchanging a management frame or action frame between an initiator 102 and a responder 104. Initiator 102 accesses a wireless medium, which requires some delay corresponding to contention or access delay under the IEEE 802.11 standard, and responds to an action frame (e.g., a mode request frame). (Step 112). In the case of correctly receiving the action frame, the responder 104 accesses the wireless medium, which also has some delay (e.g., a delay corresponding to short inter-frame spacing (SIFS)). And sends an ACK packet to the initiator (step 114). The responder 104 then prepares an action frame (e.g., a mode response frame) containing the data requested by the initiator 102, and then requires some delay due to contention or access delay. Access the wireless medium again and send this action frame to the initiator (step 116). At this time, the delay may be substantially long because other stations are unable to exchange packets at that time, so that the responder 104 cannot access the desired wireless medium. Upon receipt of the action frame correctly from the responder 104, the initiator 102 accesses the wireless medium requiring some delay (typically a time period corresponding to SIFS) and sends an ACK packet to the responder 104. (Step 118).

In the prior art process 100, the responder 104 must first send an ACK packet (step 114), then a contention or access delay must occur in step 116 to access the wireless medium and send a response frame. This slow management or action frame response may degrade the performance of the WLAN because it may not be effective or relevant at the time the information is delivered. For example, by transmission mode feedback, the responder 104 specifies or indicates initiator transmission related information, including data rate, modulation and coding scheme (MCS), number of spatial streams in MIMO, and guard intervals. Information should be exchanged as soon as possible. However, under the prior art scheme, this exchange of information may be substantially delayed.

Thus, a new mechanism is needed to exchange management or action frames within a very short period of time.

The present invention relates to a method and system for improving responsiveness when exchanging management and control frames in a WLAN. The initiator sends a frame (action, management, control or data frame) to the responder. In the case of correctly receiving this frame, the responder sends a response frame to the initiator instead of sending an ACK packet directly. The responder preferably accesses the wireless medium and transmits a response frame within SIFS. In this way, the long delay associated with competing in the wireless medium to send a response frame can be avoided, thereby significantly improving the responsiveness and timeliness of the feedback mechanism. The response frame may be piggybacked on another packet or integrated with another packet.

Hereinafter, the terms "initiator" and "responder" refer to user equipment (UE), wireless transmit / receive unit (WTRU), mobile station, fixed or mobile subscriber station, pager, node-B, base station. , Site controller, access point or any other type of device capable of operating in a wireless environment.

Features of the invention may be integrated in integrated circuits (ICs) or configured in circuits having a plurality of interconnecting components.

2 is a signaling diagram of a process 200 for exchanging action frames between an initiator 202 (also known as a sender) and a responder 204 (also known as a receiver) in accordance with the present invention. Initiator 202 is a communication entity having a transmit opportunity (TXOP) and is a frame exchange sequence that includes an aggregate physical layer protocol data unit (A-PPDU) or integrated control frames. Transmits the first frame. Responder 204 is a communication entity that responds to initiator 202 in a frame exchange sequence that includes a control frame integrated with the A-PPDU. The initiator 202 sends an action frame (usually a request frame, such as a mode request frame) to the responder 202 (step 212). If the action frame is correctly received, instead of sending an ACK packet directly, the responder 204 sends a responding action frame (eg, a mode response frame) (step 214). Hereinafter, the present invention will be described with reference to action frames. However, the present invention can be equally applied to any type of frame, such as a management frame, a control frame, a data frame, and the like. The request frame and the response frame may be other types of frames.

Responder 204 preferably accesses the wireless medium and sends a response action frame in a time period corresponding to SIFS. The initiator 202 then sends an ACK frame, preferably after a short delay corresponding to its SIFS. According to the present invention, the long delay associated with contention for the wireless medium in step 116 of FIG. 1 can be avoided, thereby greatly improving the responsiveness and timeliness of the feedback mechanism.

Alternatively, in step 214 the response action frame may be piggybacked on an ACK frame, another management or control frame, or data packet, or integrated with the ACK frame, another management or control frame, or data packet. May be When the ACK frame is piggybacked or merged, the ACK packet sent in response to the initiation action frame (i.e., the mode request frame) is not dropped, but is sent with another frame.

The signaling mechanism of the present invention may be implemented by default or in accordance with common procedures established for both the initiator 202 and the responder 204. In this case, additional fields are included in the action frame (including management frame, control frame, data frame, etc.) to indicate the desired signaling mechanism. For example, the initiator 202 may request frame (eg, mode request frame, MIMO channel request frame), MCS request (MRQ) frame, channel state information (CSI) request frame, calibration start frame, transmit antenna selection. Send a sounding request frame, training request (TRQ) frame, etc.) and set a new field in the request frame that indicates how the responder 204 wants to respond to the request frame.

The new field includes, but is not limited to, an ACK policy field, a request identity number field, a response time policy field, and an integration policy field. The ACK policy field indicates whether the responder 204 needs to send an ACK packet.

The Request Identity Number field contains a Request Identity Number. The response frame uses a similar request identity number field with a value corresponding to the request identity number in the request frame. Alternatively, the Request Identity Number field in the response frame may be set to a specific value if the response frame is transmitted as often as possible, as will be discussed in detail later.

The response time policy field may indicate that the responder 204 has sent the response frame to the initiator 202 immediately (i.e., SIFS) or within a certain time period longer than a short delay, or the number of times the responder 204 selects (i.e. not requested). Or not).

The unified policy field may be used by the responder 204 to send a response frame that is piggybacked on another packet or by using other packets such as an ACK packet, a management or control packet, a data packet, or any other type of packet. Indicates whether it is integrated. The plurality of management frames may be integrated in the packet. A block ACK (BA) may be used if a simple ACK is used and one or more MMPDUs are transmitted as part of an aggregate, if the MMPDU is transmitted alone (i.e., not part of an aggregate).

If the ACK policy is selected to include an ACK for the response frame, the following schemes may apply. The MMPDU is assigned a sequence number (SN) by the initiator 202 using a single counter, which is not unique to the responder, and is also used for broadcast / multicast frames and for non-QoS data subtype frames. do. According to the present invention, the management frames may be sequenced using a new separate SN counter unique to the responder. Alternatively, management frames may be sequenced using the same SN counter as the SN counter of the data incorporating the management frames. Since the gap in the received SN cannot be used to explicitly identify lost frames by this responder 204, another method uses the same IEEE 802.11e method of assigning SN to management frames, and responder 204. May not rearrange management frames. The initiator 202 is only required to store a copy of these related frames specified in the ACK policy field until management frames have been acknowledged or their duration has expired.

For a block ACK request (BAR) for a management frame, the ACK policy field of the new MMPDU may be described as a BAR. Alternatively, a separate BAR MAC Protocol Data Unit (MPDU) for related frames may be sent as part of an aggregate (ie, the aggregate includes a BAR frame for data frames and a BAR frame for management frames). have. Alternatively, the original BAR MPDU format may be extended to include an additional portion for management frames (ie, the aggregate may have one bar, one portion for each management frame and one portion for a data frame). ) Frame).

For a BA packet, a separate BA MPDU for a management frame may be sent as this part of the coalesce (ie, the coalesce contains a BA packet for the data frame and a BA packet for the management frame). Alternatively, the conventional BA MPDU format may be extended to include an additional portion for acknowledging management frames.

For the format of BA and BAR packets that support management frames, the BA and BAR packets used for management frames may be manufactured in the same or similar manner as the conventional format, and may be explicitly used using bit or specific field assignments. It may be identified. BA and BAR may use the concept of a starting sequence number (SSN) followed by a bitmap. If the bit position n of the BA bitmap is set to 1, this allows acknowledgment of receipt of an MPDU having a sequence control value equal to BA SSN + n. If bit position n of the BA bitmap is set to 0, this indicates that an MPDU having an MPDU sequence control value equal to (BA SSN + n) was not successfully received. Typically, unified management frames tend to have a scalable SN. If the unified management frames have a large gap in the SN (eg, unify retransmitted frames and new frames), it is possible to use (integrate) multiple BAs, each BA having a different management frame Or acknowledge frames. For example, if bitmaps have a predetermined maximum size (e.g., 16 bits) and the integrated management frames have a sequence number that differs by more than 15, they cannot be acknowledged in the same bitmap, Another BA frame is needed. BA and BAR may simply list the SN for each related management frame.

An MRQ frame, an MCS feedback (MFB) frame, and a training request (TRQ) frame including new fields are described here by way of example. However, any other management, control or data frame may include new fields that improve the responsiveness of packet exchange.

The MRQ frame is a management frame of category HT. The MRQ frame is used to request MCS feedback from the responder 204. The MRQ frame includes one or more ACK policy fields, a request identity number field, a response time policy field and an unified format field in addition to the MCS request field as shown in Table 1. The ACK policy field is set to either "No-ACK" (ie, requesting a direct MFB frame response) or "ACK" (ie, requesting an ACK packet). The Request Identity Number field is set to the Request Identity Number if an MFB packet is expected once, or set to '0' if the MFB packet is transmitted as often as possible. The Response Time Policy field is set to "Immediate" (ie SIFS), "Delayed" or "Not Requested". If the response time policy is set to "immediately", the responder 204 attempts to send an MFB frame immediately (ie, within SIFS). If the response time policy is set to "delayed", the responder 204 attempts to send an MFB frame at a particular delay time. The unified format field may be set to "Integrated MAC Protocol Data Unit" (A-MPDU), "RIFS-PPDU" or "No-Aggregation". If the unified format field is set to "A-MPDU", responder 204 and initiator 202 attempt to send an A-MPDU. If the unified format field is set to "RIFS-PPDU", responder 204 and initiator 202 attempt to send a plurality of MPDUs using RIFS, but may generate an A-MPDU. If the unified format field is set to non-integrated, responder 204 and initiator 202 do not attempt to unify MFB frames. Alternatively, if the unified format field is not included in the MRQ frame or the MFB frame, then the responder 204 or the initiator 202 decides itself without being instructed by another party through this unified format field. You can also perform the integration. The MCS Request indicates the requested feedback type.

Body field order Frame Body Field Information for MCS Request Frame One ACK policy 2 Request identity number 3 Request time policy 4 Unified format 5 MCS Request

                                  Table 1

The MFB frame is a management frame of category HT. The MFB frame is transmitted in response to or independently of the MRQ frame. The MFB frame includes one or more of an ACK policy field, a request identity number field, a response time policy field, and an integrated format field in addition to the MFB field as shown in Table 2. The ACK policy field is set to either "No-ACK" or "ACK". The Request Identity Number field is set to the corresponding request number from the MRQ frame if requested or '0' if the MFB frame is transmitted as often as possible or not requested. The response time policy field is set to "immediately" (ie SIFS), "delayed" or "unsolicited". The unified format field may be set to "A-MPDU", "RIFS-PPDU" or "No-Aggregation". The operations of the ACK policy field, the request identity number field, the response time policy field, and the unified format field are the same as the operation of the MRQ frame, and thus are not repeated here for the sake of brevity. The MCS Feedback field contains an MCS Response.

Body field order Frame Body Field Information for MCS Feedback Frames One ACK policy 2 Request identity number 3 Response time policy 4 Unified format 5 MCS Feedback

                                  Table 2

The TRQ frame is a management frame of category HT. The TRQ frame requests that the next transmission by the responder 204 be a sounding PPDU with specific physical layer attributes. The TRQ frame includes one or more of an ACK policy field, a request identity number field, a response time policy field, and an integrated format field in addition to the channel sounding parameter field as shown in Table 3. The ACK policy field is set to one of "No-ACK" or "ACK". The Request Identity Number field is set to the number of requests based on the training procedure. The response time policy field is set to "immediately" (SIFS), "delayed" or "unsolicited". The unified format field is set to "A-MPDU", "RIFS-PPDU" or "No-Aggregation". The operations of the ACK policy field, the request identity number field, the request time policy field, and the unified format field are the same as those of the MRQ frame, and thus are not repeated here for the sake of brevity. The channel sounding parameter field indicates the number and type of the HT-long training field (LTF), the number of transmit and receive antennas, and the like.

Field order Frame Body Field Information for Training Request (TRQ) Frames One ACK policy 2 Request identity number 3 Response time policy 4 Unified format 5 Channel sounding parameters

                                        TABLE 3

New fields (i.e. one or more of the ACK policy field, request identity number field, response time policy field, and unified format field) may include mode request frames, mode response frames, MIMO channel request frames, MIMO channel response frames, CSI feedback request frames, It may be included in any type of frame such as a CSI feedback request frame, a calibration start frame, a calibration sounding response frame, a transmit antenna selection sounding request frame, an antenna selection feedback frame, and the like.

Mode request frames and mode response frames are used to exchange optimal transmission modes for use in high throughput communications. The MIMO channel request frame, the MIMO channel response frame, the CSI feedback request frame, and the CSI feedback response frame are used to exchange CSI between the initiator 202 and the responder 204. A calibration start frame and a calibration sounding response frame are used for calibration purposes to eliminate differences in the transmit and receive chains of the initiator 202 and the responder 204. The transmit antenna selection sounding request frame and antenna selection feedback frame are used for antenna selection by the initiator 202 or the responder 204.

3 illustrates an example process 300 for exchanging packets between an initiator 302 and a responder 304 using an A-MPDU with an ACK policy designated as No-ACK for an MMPDU in accordance with the present invention. Initiator 302 generates a requeqt-to-send (RTS) frame 312 when there is data to be sent to responder 304 and uses the base rate non-integrated PPDU 314 to generate this RTS frame. 312 is sent to the responder 304. Upon receipt of the RTS frame 312, the responder 304 sends a clear-to-send (CTS) frame 316 to the initiator 302 using the base rate non-integrated PPDU 318. After receiving this CTS frame 316, the initiator 302 generates an A-MPDU 320 that includes an MRQ MMPDU 320a, a data MPDU 320b, and a BAR MPDU 320c. The A-MPDU 320 is transmitted using the integrated PPDU (A-PPDU) 322, which is generated based on the default MIMO and the default MCS.

Since the ACK policy field of the MRQ MMPDU 320a is set to No-ACK, the responder 304 directly sends the MFB MMPDU 314a without ACKing to acknowledge receipt of the MRQ MMPDU 320a. Responder 304 generates an A-MPDU 324 comprising an MFB MMPDU 324a and a BA 324b to acknowledge receipt of the data MPDU 320b and using the A-PPDU 326 to generate the A-MPDU 324. Transmit the MPDU 324.

The initiator 302 receives the MFB MMPDU 324a and selects the optimized MCS according to the MCS feedback included in the MFB MMPDU 324a. Initiator 302 creates another A-MPDU 328 that includes data MPDU 328a and BAR MPDU 328b, and uses A-PPDU 320 with an optimized rate based on MCS feedback. Send it. The responder 304 then sends the BA 332 using the unintegrated PPDU 334 in response to the BAR MPDU 328b. After successful transmission of data, the initiator 302 sends a CF-Poll END frame 336 to release the TXOP using the base rate non-integrated PPDU 338.

4 illustrates another exemplary process 400 for exchanging packets between an initiator 402 and a responder 404 using an A-MPDU with an ACK policy designated as No-ACK for an MMPDU in accordance with the present invention. Indicates. The initiator 4022 generates an RTS frame 412 when there is data to be sent to the responder 404, and uses the non-integrated PPDU 414 at the base rate to respond to the responder 404. To). Upon receipt of the RTS frame 412, the responder 404 sends the CTS frame 416 to the initiator 402 using the non-integrated PPDU 418 at the base rate. After receiving the CTS frame 416, the initiator 402 receives the A-MPDU 420, which includes the TRQ MMPDU 420a, the MRQ MMPDU 420b, the data MPDU 420c, and the BAR MPDU 420d. Create The A-MPDU 420 is transmitted using the integrated PPDU 422, which is generated based on the default MIMO and the default MCS.

Since the ACK policy fields of the TRQ MMPDU 420a and the MRQ MMPDU 420b are set to No-ACK, the responder 404 directly sends the MFB MMPDU without sending a separate ACK to acknowledge receipt of the MRQ MMPDU 420b. Send 424a. Responder 404 generates A-MPDU 424 including MFB MMPDU 424a and BA 424b and uses sounding A-PPDU 426 as requested by TRQ MMPDU 420a. Send it.

Initiator 402 then receives sounding PPDU 426 and estimates channel selection information (CSI) based on this sounding PPDU 426. The estimated CSI is used to set the MIMO parameter at the transmission of the next packet. The initiator 402 also receives the MFB MMPDU 424a and selects the optimized MCS according to the MFB frame included in the MFB MMPDU 424a. Initiator 402 generates another A-MPDU 428 that includes TRQ MMPDU 428a, MRQ MMPDU 428b, data MPDU 428c, and BAR MPDU 428d, and A-PPDU 430 This A-MPDU 428 is transmitted by using. A-PPDU 430 is generated based on MCS and MIMO parameters optimized according to CSI and MFB. Responder 404 receives A-MPDU 428, generates another A-MPDU 432 that includes MFB MMPDU 432a and BA 432b, and uses another sounding PPDU 434. Send it. The initiator 402 receives the sounding A-PPDU 434, estimates the CSI, and selects the MCS based on the MFB. Initiator 402 creates another A-MPDU 436 that includes data MPDU 436a and BAR MPDU 436b and transmits it using A-PPDU 438. A-PPDU is generated based on the MCS and MIMO parameters updated according to the second CSI and MFB. The responder 404 then sends the BA 440 in response to the BAR MPDU 436b using the non-integrated PPDU 442. After successful transmission of data, the initiator 402 sends a CF-Poll End frame 444 to release the TXOP using the base rate non-integrated PPDU 446.

FIG. 5 shows an exemplary process 500 for exchanging packets between an initiator 502 and a responder 504 using RIFS with an ACK policy designated as No-ACK for the MMPDU according to the present invention. The initiator 502 generates an RTS frame 512 when there is data to be sent to the responder 504 and uses the base rate non-integrated PPDU 514 to send the RFS frame 512 to the responder 504. To). Upon receipt of the RTS frame 512, the responder 504 sends the MRQ MMPDU 520 using the non-integrated PPDU 522 at the base rate. Without releasing the TXOP, the initiator 502 also creates an A-MPDU 524 that includes the data MPDU 524a and the BAR MPDU 524b, and the PPDU 522 using the A-PPDU 526. A-MPDU 524 is sent after RIFS from the transmission.

After receiving the MRQ MMPDU 520, the responder 504 is set to the ACK policy field No-ACK of the MRQ MMPDU 520 and thus directly transmits the MFB MMPDU 528 without transmitting the ACK. Without releasing the TXOP, the responder 504 generates a BA frame 532 to acknowledge receipt of the data MPDU 524a and from the transmission of the PPDU 530 using the unintegrated PPDU 534. Send the BA 532 after the RIFS.

The initiator 502 receives the MFB MMPDU 528 and selects an optimized MCS according to the MFB included in the MFB MMPDU 528. The initiator 502 generates an A-MPDU 536 that includes a data MPDU 536a and a BAR MPDU 536b, and generates an A-PPDU (i. The A-MPDU 536 is transmitted using the 538. Responder 504 then sends BA 540 to acknowledge receipt of data MPDU 536a using non-aggregated PPDU 542. [ After successful transmission of data, the initiator 504 sends a CF-Poll END frame to release the TXOP using the non-integrated PPDU 546 at the base rate.

6 shows another exemplary process 600 for exchanging packets between an initiator 602 and a responder 604 using RIFS with an ACK policy designated as No-ACK for MMPDUs in accordance with the present invention. Initiator 602 generates an RTS frame 612 if there is data to send to responder 604 and sends this RFS frame 612 to responder 604 using non-aggregated PPDU 614 at base rate . Upon receipt of the RTS frame 612, the responder 604 sends the CTS frame 616 to the initiator 602 using the non-integrated PPDU 618 at the base rate. After receiving the CTS frame 616, the initiator 602 generates a TRQ MMPDU 620 and transmits this TRQ MMPDU 620 using the unintegrated PPDU 622. In the same TXOP, the initiator 602 also creates an MRQ MMPDU 624 and transmits the MRQ MMPDU 624 after RIFS from the transmission of the PPDU 622 using the non-integrated PPDU 626. In addition, in the same TXOP, the initiator 602 generates an A-MPDU 628 that includes a data MPDU 628a and a BAR MPDU 628b, and uses the A-PPDU 630 to generate the A-MPDU ( 628). This A-PPDU 630 is generated based on the default MIMO parameters and the default MCS.

Responder 604 receives TRQ MMPDU 620 and MRQ MMPDU 624, generates MFB MMPDU 632, and via the sounding A-PPDU 634 as requested by TRQ MMPDU 620. send. Since the ACK policy fields of TRQ MMPDU 620 and MRQ MMPDU 624 are set to No-ACK, responder 604 sends a separate ACK to acknowledge receipt of TRQ MMPDU 620 and MRQ MMPDU 624. MFB MMPDU 632 is sent directly without doing so.

In the same TXOP, responder 604 also generates BA 636 to acknowledge receipt of data MPDU 628b and after RIFS from transmission of PPDU 634 using non-integrated PPDU 638. Send a BA 636.

Initiator 602 then receives sounding PPDU 634 and estimates the CSI based on the sounding PPDU 634. The estimated CSI is used to set the MIMO parameters at the transmission of the next packet. In addition, the initiator 602 receives the MFB MMPDU 632 and selects an optimized MCS according to the MFB included in the MFB MMPDU 632.

Initiator 602 generates a second TRQ MMPDU 640 and sends it via A-PPDU 642. In the same TXOP, the initiator 602 also generates a second MRQ MMPDU 644 and sends it after RIFS from the transmission of the A-PPDU 642 using the A-PPDU 646. In addition, in the same TXOP, the initiator 602 generates an A-MPDU 648 that includes a data MPDU 648a and a BAR MPDU 618b and uses the A-PPDU 650 to generate the PPDU 646. This A-MPDU 648 is sent after RIFS from the transmission. A-PPDUs 642, 646, 650 are generated based on MCS and MIMO parameters optimized according to CSI and MFB.

Responder 604 receives the second TRQ MMPDU 640 and the second MRQ MMPDU 644, generates a second MFB MMDPU 652, and uses the second sounding A-PPDU 654 to generate the MFB. Send MMPDU 652. In the same TXOP, responder 604 also generates BA 656 to acknowledge receipt of data MPDU 648 and sends BA 656 using unintegrated PPDU 658.

After receiving the second sounding A-PPDU 654 including this second MFB MMPDU 652, the initiator 602 estimates the CSI and based on the new MFB included in the MFB MMPDU 652. Select MCS. The initiator 602 generates a third A-MPDU 670 that includes a data MPDU 670a and a BAR MPDU 670b and uses the A-PPDU 672 to generate the third A-MPDU 670. The A-PPDU 672 is generated based on the optimized MCS and MIMO parameters according to the updated CSI and MFB.

Responder 604 receives A-MPDU 670 and sends BA 674 to acknowledge receipt of data MPDU 670a using non-integrated PPDU 676. After successful transmission of the data, the initiator 602 sends a CF-Poll END frame 678 to release the TXOP using the non-integrated PPDU 680 at the base rate.

According to another embodiment of the present invention, action, management or control frames may be prioritized over data frames. This prioritization can be explicitly achieved through designated fields in an action, management or control frame when accessing a wireless medium, or it can be a hardware or software implementation that handles higher priority action, management or control frames. May be potentially achieved. This prioritization scheme is used for all action, management or control frames proposed by TGnSync or by WWiSe, in particular the action and management frames used for transmission mode feedback and channel feedback (e.g., mode request, mode response, MIMO). Channel request, MIMO channel response, MRQ frame, TRQ frame).

While the features and elements of the invention have been described in particular embodiments in the preferred embodiments, each feature or element may be used alone without the other features and elements of the preferred embodiments, or with other features and elements of the invention. May be used in various combinations of or without them.

As described above, the present invention can provide a method and system for improving responsiveness when exchanging management and control frames in a WLAN.

Claims (77)

A method for use in a first station (STA), The first station sending a first management action frame to a second station, the first management action frame sending any acknowledgment (ACK) by the second station in response to the first management action frame. Sending an first management action frame comprising an ACK policy field indicating that it will not be; The second station receives the second management action frame in response to the first management action frame without receiving a separate ACK frame acknowledging receipt of the first management action frame by the second station. Receiving from the station Including, And wherein the second management action frame is received within a short inter-frame spacing (SIFS) of the first management action frame. delete The method of claim 1, wherein the second management action frame is piggybacked on another frame. The method of claim 1, wherein the second management action frame is aggregated with another frame. 2. The method of claim 1, wherein the first station transmits a third management action frame including an ACK policy field to another station, wherein the ACK policy field identifies receipt of the third management action frame as a separate ACK frame. Sending the third management action frame to the other station to respond; And receiving an ACK frame from the other station in response to the third management action frame prior to the first station receiving a fourth management action frame. 2. The method of claim 1, wherein the first management action frame includes a request identity number field indicating a request identity number. The first station of claim 1, wherein the first management action frame includes a response time policy field indicating whether the second management action frame should be received immediately or within a predetermined time period. Method for use in The method of claim 1, wherein the first management action frame includes an aggregation policy field indicating whether the second management action frame can be integrated with at least one other frame. 1 Method for use at the station. 9. The method of claim 8, wherein the coalescing policy field indicates that a plurality of packets should be received at Reduced Inter-Frame Spacing (RIFS). The method of claim 1, wherein the first management action frame includes a training request, and the second management action frame includes a sounding frame. Estimating channel state information (CSI) from the sounding frame; Transmitting the next frame based on the estimated CSI Further comprising a method for use at the first station. 2. The method of claim 1, wherein the first management action frame includes a channel state information (CSI) feedback request and the second management action frame includes a CSI feedback response. 12. The method of claim 11, wherein the CSI is used for at least one of transmit beam forming, calibration, and antenna selection. The method of claim 1, wherein the first management action frame and the second management action frame are each different types of frames. The method of claim 1, wherein the first management action frame includes a Modulation and Coding Scheme (MCS) request, the second management action frame includes MCS feedback, The method further comprising generating a next frame based on the MCS feedback. In the station (STA), A transmitter configured to transmit a first management action frame to a second station, the first management action frame indicating that no acknowledgment (ACK) will be sent by the second station in response to the first management action frame An ACK policy field; Short interframe space (SIFS) of the first management action frame in response to the first management action frame without receiving a separate ACK frame acknowledging receipt of the first management action frame by the second station. Within, a receiver configured to receive a second management action frame from the second station Station comprising a. delete 16. The station of claim 15, wherein the receiver is configured to receive the second management action frame that is piggybacked on another frame. 16. The station of claim 15, wherein the receiver is configured to receive the second management action frame that is integrated with another frame. 16. The apparatus of claim 15, wherein the transmitter is configured to transmit a third management action frame including an ACK policy field, wherein the ACK policy field is further configured to acknowledge receipt of the third management action frame as a separate ACK frame. To the station, Wherein the receiver is configured to receive an ACK frame from the other station in response to the third management action frame prior to receiving a fourth management action frame. 16. The station of claim 15, wherein the transmitter is configured to transmit the first management action frame that includes a request identity number field indicating a request identity number. 16. The apparatus of claim 15, wherein the transmitter is configured to transmit the first management action frame including a response time policy field indicating whether the second management action frame should be received immediately or within a predetermined time period. Station. 16. The station of claim 15, wherein the transmitter is configured to transmit the first management action frame including an integration policy field indicating whether the second management action frame can be integrated with another frame. 23. The station of claim 22, wherein the coalescing policy field indicates that the station should receive a plurality of packets at a reduced interframe space (RIFS). The apparatus of claim 15, wherein the transmitter is configured to send the first management action frame comprising a training request, the receiver is configured to receive the second management action frame as a sounding frame, and the station is configured to: A processor configured to estimate channel state information (CSI) from the sounding frame, The transmitter is further configured to transmit a next frame based on the estimated CSI. 16. The apparatus of claim 15, wherein the transmitter is configured to transmit the first management action frame comprising a channel state information (CSI) feedback request and the receiver is configured to receive the second management action frame comprising a CSI feedback response. Station configured. 27. The station of claim 25, further comprising a processor configured to use the CSI for at least one of transmit beam forming, calibration, and antenna selection. 16. The station of claim 15, wherein the transmitter is configured to transmit the first management action frame as a first type of frame and the receiver is configured to receive the second management action frame as a second type of frame. 16. The apparatus of claim 15, wherein the transmitter is configured to send the first management action frame comprising a modulation and coding method (MCS) request and the receiver is configured to receive the second management action frame including MCS feedback. And the transmitter is configured to transmit the next frame based on the MCS feedback. In a method for use in a first station, The first station receiving a first management action frame from a second station, wherein the first management action frame is not sent any acknowledgment (ACK) to the second station in response to the first management action frame. Receiving an first management action frame comprising an ACK policy field indicating that it will not; The second station transmits a second management action frame in response to the first management action frame without transmitting a separate ACK frame acknowledging receipt of the first management action frame by the first station. Steps to the station Including, And wherein the second management action frame is transmitted within a short interframe space (SIFS) of the first management action frame. delete 30. The method of claim 29, wherein the second management action frame is piggybacked on another frame. 30. The method of claim 29, wherein the second management action frame is integrated with another frame. 30. The method of claim 29, wherein the second management action frame is transmitted without sending a separate ACK frame by default. 30. The method of claim 29, wherein the first station receives a third management action frame that includes an ACK policy field from another station, wherein the ACK policy field is separate to acknowledge receipt of the third management action frame. Receiving the third management action frame, indicating to the first station to transmit an ACK frame; Transmitting an ACK frame to the other station in response to the third management action frame before the first station transmits a fourth management action frame Further comprising a method for use at the first station. 30. The method of claim 29, wherein the first management action frame includes a request identity number field indicating a request identity number. 30. The method of claim 29, wherein the first management action frame includes a response time policy field indicating whether a sounding physical layer protocol data unit (PPDU) should be sent immediately or within a predetermined time period. , Method for use in a first station. 30. The method of claim 29, wherein the first management action frame includes an integration policy field indicating whether the second management action frame can be integrated with at least one other frame. Way. 38. The method of claim 37, wherein the coalescing policy field indicates that a plurality of packets should be sent at a reduced interframe space (RIFS). 30. The method of claim 29, wherein the first management action frame includes a training request, and the second management action frame includes a sounding frame, The method further comprising receiving a next frame based on channel state information (CSI). 30. The method of claim 29, wherein the first management action frame includes a channel state information (CSI) feedback request and the second management action frame includes a CSI feedback response. 41. The method of claim 40, wherein the CSI is used for at least one of transmit beam forming, calibration, and antenna selection. 30. The method of claim 29, wherein the first management action frame and the second management action frame are each different types of frames. 30. The method of claim 29, wherein the first management action frame includes a modulation and coding method (MCS) request, the second management action frame includes MCS feedback, and a next frame is received based on the MCS feedback. Method for use in a first station. In the station (STA), A receiver configured to receive a first management action frame from a second station, wherein the first management action frame indicates that no acknowledgment (ACK) will be sent to the second station in response to the first management action frame. A receiver comprising a policy field; In response to the first management action frame, without transmitting a separate ACK frame acknowledging receipt of the first management action frame by the station, within a short interframe space (SIFS) of the first management action frame. A transmitter configured to transmit a second management action frame to the second station Station comprising a. delete 45. The station of claim 44, wherein the transmitter is configured to transmit the second management action frame that is piggybacked on another frame. 45. The station of claim 44, wherein the station is configured to transmit the second management action frame integrated with the other frame. 45. The station of claim 44, wherein the transmitter is configured to transmit the second management action frame without sending a separate ACK frame by default. 45. The apparatus of claim 44, wherein the receiver is configured to receive a third management action frame comprising an ACK policy field, wherein the ACK policy field tells another station to acknowledge receipt of the third management action frame as a separate ACK frame. To indicate, The transmitter is configured to send an ACK to the other station prior to sending a fourth management action frame. 45. The station of claim 44, wherein the receiver is configured to receive the first management action frame including a request identity number field indicating a request identity number. 45. The station of claim 44, wherein the receiver is configured to receive the first management action frame including a response time policy field indicating whether the transmitter should transmit immediately or within a predetermined time period. 45. The apparatus of claim 44, wherein the receiver is configured to receive the first management action frame including an integration policy field indicating whether the station can integrate the second management action frame with another frame. station. 53. The station of claim 52, wherein the aggregation policy field indicates that a plurality of packets should be sent at a reduced Interframe Interval (RIFS). 45. The apparatus of claim 44, wherein the receiver is configured to receive the first management action frame comprising a training request, the transmitter is configured to send the second management action frame as a sounding frame, and the receiver is further configured to: And receive the next frame based on channel state information (CSI). 45. The apparatus of claim 44, wherein the receiver is configured to receive the first management action frame comprising a channel state information (CSI) feedback request, and wherein the transmitter is configured to transmit the second management action frame comprising a CSI feedback response. Station configured. 56. The station of claim 55, further comprising a processor configured to use the CSI for at least one of transmit beam forming, calibration, and antenna selection. 45. The station of claim 44, wherein the receiver is configured to receive the first management action frame as a frame of a first type, and wherein the transmitter is configured to transmit the second management action frame as a frame of a second type. 45. The apparatus of claim 44, wherein the receiver is configured to receive the first management action frame comprising a modulation and coding method (MCS) request and the transmitter is configured to transmit the second management action frame including MCS feedback. Station. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

Images