Method for communicating encoded traffic indication map information
Provided is a method of communicating encoded traffic indication map (TIM) information that can reduce power consumption by reducing an unnecessary decoding process. A method of receiving, by a terminal, a TIM that is encoded in a hierarchical structure including a page, a block, and a sub-block includes receiving an encoded TIM from an access point (AP), extracting a page index from the encoded TIM, and extracting block bitmap information indicating whether blocks included in a page designated by the page index include a bitmap. Therefore, an unnecessary decoding process with respect to each delivery traffic indication map (DTIM) beacon can be reduced, thereby reducing power consumption of a low-power terminal.
1. A method of receiving, by a terminal, a traffic indication map (TIM) of a hierarchical structure that a page includes one or more blocks and a block includes one or more sub-blocks, the method comprising:
receiving a beacon frame including a page index field, a block offset field and a first bitmap field for a plurality of blocks from an access point (AP), the first bitmap field for the plurality of blocks has a maximum length of 4 octets; and
determining, based on the first bitmap field for the plurality of blocks corresponding to an offset of blocks, whether performing overall decoding or not for the plurality of the blocks included in the TIM, the plurality of blocks are included in a page designated by the page index field,
wherein the block offset field indicates the offset of blocks,
wherein the first bitmap field indicates, for each of the plurality of blocks, whether there is data for at least one terminal corresponding to a block of the plurality of blocks,
wherein the beacon frame further includes a second bitmap field for a plurality of sub-blocks, the second bitmap field indicating, for each of the plurality of sub-blocks, whether there is data for at least one terminal corresponding to a sub-block of the plurality of sub-blocks, and
wherein each bit of a sub-block indicates whether there is data for a terminal corresponding to a bit position of the sub-block.
2. The method of claim 1 ,
wherein, when bits for designating a block including an association ID (AID) of the terminal are set in the first bitmap field for the plurality of blocks, the plurality of blocks including the AID of the terminal are determined to be decoded.
3. The method of claim 1 ,
wherein, when bits for designating a block including an AID of the terminal are not set in the first bitmap field for the plurality of blocks, the plurality of blocks are determined not to be decoded.
4. The method of claim 3 , wherein, when bits for designating a block including an AID of the terminal are not set in the first bitmap field for the plurality of blocks, the plurality of blocks are determined not to be decoded, and the terminal enters a power save mode.
5. The method of claim 1 ,
wherein the second bitmap field has a length of 1 octet, and
wherein an association identifier (AID) of the terminal is constructed by concatenating:
3 bits corresponding to a bit position index in a sub-block,
3 bits corresponding a sub-block index in a block,
5 bits corresponding to a block index, and
2 bits corresponding to the page index.
6. A method of transmitting, by an AP, a TIM of a hierarchical structure that a page includes one or more blocks and a block includes one or more sub-blocks, the method comprising:
generating a beacon frame including a page index field, a block offset field, and a first bitmap field for a plurality of blocks, the first bitmap field for the plurality of blocks has a maximum length of 4 octets; and
transmitting the beacon frame to a terminal,
wherein whether performing overall decoding or not for the plurality of the blocks included in the TIM is determined based on the first bitmap field for the plurality of blocks corresponding to an offset of blocks, the plurality of blocks are included in a page designated by the page index field,
wherein the block offset field indicates the offset of blocks,
wherein the first bitmap field indicates, for each of the plurality of blocks, whether there is data for at least one terminal corresponding to a block of the plurality of blocks,
wherein the beacon frame further includes a second bitmap field for a plurality of sub-blocks, the second bitmap field indicating, for each of the plurality of sub-blocks, whether there is data for at least one terminal corresponding to a sub-block of the plurality of sub-blocks, and
wherein each bit of a sub-block indicates whether there is data for a terminal corresponding to a bit position of the sub-block.
7. The method of claim 6 ,
wherein the second bitmap field has a length of 1 octet, and
wherein an association identifier (AID) of the terminal is constructed by concatenating:
3 bits corresponding to a bit position index in a sub-block,
3 bits corresponding a sub-block index in a block,
5 bits corresponding to a block index, and
2 bits corresponding to the page index.
8. A terminal receiving a traffic indication map (TIM) of a hierarchical structure that a page includes one or more blocks and a block includes one or more sub-blocks, the terminal comprising:
a transceiver; and
a processor,
wherein the processor is configured to:
receive, using the transceiver, a beacon frame including a page index field, a block offset field and a first bitmap field for a plurality of blocks from an access point (AP), the first bitmap for the plurality of blocks has a maximum length of 4 octets;
determine whether performing overall decoding or not for the plurality of the blocks included in the TIM based on the first bitmap field for the plurality of blocks corresponding to an offset of blocks, the plurality of blocks are included in a page designated by the page index field,
wherein the block offset field indicates the offset of blocks,
wherein the first bitmap field indicates, for each of the plurality of blocks, whether there is data for at least one terminal corresponding to a block of the plurality of blocks,
wherein the beacon frame further includes a second bitmap field for a plurality of sub-blocks, the second bitmap field indicating, for each of the plurality of sub-blocks, whether there is data for at least one terminal corresponding to a sub-block of the plurality of sub-blocks, and
wherein each bit of a sub-block indicates whether there is data for a terminal corresponding to a bit position of the sub-block.
9. The terminal of claim 8 ,
wherein the second bitmap field has a length of 1 octet, and
wherein an association identifier (AID) of the terminal is constructed by concatenating:
3 bits corresponding to a bit position index in a sub-block,
3 bits corresponding a sub-block index in a block,
5 bits corresponding to a block index, and
2 bits corresponding to the page index.
10. An AP transmitting a TIM of a hierarchical structure that a page includes one or more blocks and a block includes one or more sub-blocks, the AP comprising:
a transceiver; and
a processor,
wherein the processor is configured to:
generate a beacon frame including a page index field, a block offset field and a first bitmap field for a plurality of blocks, the first bitmap field for the plurality of blocks has a maximum length of 4 octets; and
transmit, using the transceiver, the beacon frame to a terminal,
wherein whether performing overall decoding or not for the plurality of the blocks included in the TIM is determined based on the first bitmap field for the plurality of blocks corresponding to an offset of blocks, the plurality of blocks are included in a page designated by the page index field,
wherein the block offset field indicates the offset of blocks,
wherein the first bitmap field indicates, for each of the plurality of blocks, whether there is data for at least one terminal corresponding to a block of the plurality of blocks,
wherein the beacon frame further includes a second bitmap field for a plurality of sub-blocks, the second bitmap field indicating, for each of the plurality of sub-blocks, whether there is data for at least one terminal corresponding to a sub-block of the plurality of sub-blocks, and
wherein each bit of a sub-block indicates whether there is data for a terminal corresponding to a bit position of the sub-block.
11. The AP of claim 10 ,
wherein the second bitmap field has a length of 1 octet, and
wherein an association identifier (AID) of the terminal is constructed by concatenating:
3 bits corresponding to a bit position index in a sub-block,
3 bits corresponding a sub-block index in a block,
5 bits corresponding to a block index, and
2 bits corresponding to the page index.