Beamforming training
Provided are a method for beamforming training and an apparatus using the same. An STA receives a beacon frame from an AP during a BTI. The STA transmits SSW frames during an A-BFT. The beacon frame comprises an A-BFT length indicating the number of a plurality of SSW slots included in the A-BFT, a FSS field indicating the number of the SSW frames allowed in one SSW slot among the plurality of SSW slots, and information about the type of the SSW frames used in one SSW slot. The information about the type of the SSW frames indicates that the SSW frames are determined to be one from among first type SSW frames and second type SSW frames. The second type SSW frames have a smaller size than that of the first type SSW frames. If the SSW frames are determined to be the second type SSW frames, the FSS field indicates the number of the second type SSW frames that can be transmitted in one SSW slot.
1. A method in a wireless local area network (WLAN), comprising:
receiving, by a station (STA), a beacon frame from an access point (AP) during a beacon transmission interval (BTI); and
wherein the beacon frame includes an association beamforming training (A-BFT) length field including information related to a number of multiple short sector sweep (SSW) slots and a frame per SSW slot (FSS) field including information related to a number of SSW frames that can be transmitted in one SSW slot among the multiple SSW slots,
wherein the SSW frames are first type SSW frames or second type SSW frames,
wherein one second type SSW frame is shorter than one first type SSW frame, and
wherein the STA differently interprets a value of the FSS field to be a number of the first type SSW frames or a number of the second type SSW frames based on the following table:
TABLE
Value of the FSS field
0
1
2
3
4
5
6
7
Number of
1
2
3
4
5
6
7
8
first type
SSW frames
Number of
1
3
4
6
8
9
11
12
second
type SSW
frames
Value of the FSS field
8
9
10
11
12
13
14
15
Number of
9
10
11
12
13
14
15
16
first type
SSW frames
Number of
14
16
17
19
21
22
24
25;
second
type SSW
frames
and
transmitting, by the STA, the SSW frames during an association beamforming training (A-BFT) interval to the AP.
2. The method of claim 1 , wherein the STA interprets the value of the FSS field to be the number of the first type SSW frames when the SSW frames are first type SSW frames.
3. The method of claim 1 , wherein the STA interprets the value of the FSS field to be the number of the second type SSW frames when the SSW frames are second type SSW frames.
4. The method of claim 1 , wherein the FSS field has a length of 4 bits.
5. The method of claim 1 , wherein a length of the A-BFT interval is fixed regardless of a type of the SSW frames.
6. A station (STA) in a wireless local area network (WLAN), comprising:
a transceiver configured to transmit and/or receive a wireless signal; and
a processor configured to control the transceiver,
wherein the processor is further configured to:
receive, via the transceiver, a beacon frame from an access point (AP) during a beacon transmission interval (BTI); and
wherein the beacon frame includes an association beamforming training (A-BFT) length field including information related to a number of multiple short sector sweep (SSW) slots and a frame per SSW slot (FSS) field including information related to a number of SSW frames that can be transmitted in one SSW slot among the multiple SSW slots,
wherein the SSW frames are first type SSW frames or second type SSW frames,
wherein one second type SSW frame is shorter than one first type SSW frame, and
wherein the processor differently interprets a value of the FSS field to be a number of the first type SSW frames or a number of the second type SSW frames based on the following table:
TABLE
Value of the FSS field
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Number of
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
first type
SSW frames
Number of
1
3
4
6
8
9
11
12
14
16
17
19
21
22
24
25;
second
type SSW
frames
and
transmit, via the transceiver the SSW frames during an A-BFT interval to the AP.
7. The STA of claim 6 , wherein the processor interprets the value of the FSS field to be the number of the first type SSW frames when the SSW frames are first type SSW frames.
8. The STA of claim 6 , wherein the processor interprets the value of the FSS field to be the number of the second type SSW frames when the SSW frames are second type SSW frames.
9. The STA of claim 6 , wherein the FSS field has a length of 4 bits.
10. The STA of claim 6 , wherein a length of the A-BFT interval is fixed regardless of a type of the SSW frames.