Method, Apparatus and System for Transmitting Traffic Indication Message

A method, an apparatus, and a system for transmitting a traffic indication message, which relate to a wireless fidelity (WiFi) technology and are mainly applicable to a traffic indication message processing procedure. The method includes: compressing a delivery traffic indication message, and generating a traffic indication message; and transmitting the traffic indication message, where the traffic indication message includes compression method indication information and the compressed delivery traffic indication message.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following describes a method, an apparatus, and a system for transmitting a traffic indication message provided by the embodiments of the present invention in detail with reference to the accompanying drawings.

An embodiment of the present invention provides a method for transmitting a traffic indication message. As shown inFIG. 4, operation steps of an access point include:

Step101: Compress a delivery traffic indication message, and generate a traffic indication message, where the delivery traffic indication message is used for indicating whether at least one terminal device associated with the access point has data to receive, and the delivery traffic indication message indicates, through a delivery traffic indication bit corresponding to the at least one terminal device, whether the at least one terminal device has data to receive.

Step102: Transmit the traffic indication message, where the traffic indication message includes compression method indication information and the compressed delivery traffic indication message, and the compression method indication information is used for indicating a compression method adopted to compress the delivery traffic indication message.

The method for transmitting a traffic indication message provided by this embodiment of the present invention compresses a delivery traffic indication message corresponding to each terminal device, generates the traffic indication message, and then transmits the traffic indication message, thereby solving the problem that the TIM message is too long, reducing the length of a Beacon frame, and increasing the transmission efficiency.

In this specific application, compressing the delivery traffic indication message specifically includes: encoding a bitmap of the delivery traffic indication bit. Different compression methods, namely, encoding methods, may be adopted for encoding the bitmaps; and the compression methods are indicated by the compression method indication information in the traffic indication message.

The following provides a multi-block solution for compressing a delivery traffic indication message. As shown inFIG. 5, basic elements of a multi-block definition include an offset, a block length, and a bitmap. Specific definitions are as follows: offset indicates an AID of a first terminal device of which an indication bit is one in a block and may occupy 13 bytes; block length indicates the length of a block bitmap in the block; when the block length is zero, it indicates that there is no block bitmap information; therefore, the offset refers to only one AID; and the maximum block length is seven bytes, which occupy 3 bits; and block bitmap indicates a partial bitmap of one block; the maximum length of the bitmap is seven bytes, that is, one block indicates partial bitmaps of 56 terminal devices at most.

During the compressing of the TIM message, by using the multi-block solution the TIM is searched backwards, starting from AID1, for bits of which values are ones; when the first one is found, a value of an AID corresponding to the first one is filled in the Offset of the basic elements; if multiple ones appear within a range of several bytes (a range of seven bytes at most) after the first one in the TIM, bitmaps including the several bytes of which values are ones in the TIM are copied to a block bitmap, where the length (in bytes) of the block bitmap is indicated by the block length; and if no other ones appear within the range of seven bytes after the first one, the block length is set to zero, which indicates that no bitmap exists after the first one. In this way, the first basic element for compression is obtained; then, the above steps are continuously performed to search for the first one appearing afterwards, and the above steps are repeated until the searching and encoding of the whole TIM is completed. After the whole TIM is compressed, multiple basic elements are obtained.

When the compression method is adopted, the compression method needs to be indicated in the compression method indication information of the TIM message, so that when receiving the compressed TIM message, the STA may decompress the TIM message according to an algorithm indicated by the compression method indication information, so as to obtain a corresponding delivery traffic indication message. For example, when three bits are adopted to indicate the compression method indication information, 000 may indicate adopting the existing method of compressing zeroes in the front and rear; 001 may indicate adopting the multi-block compression algorithm, and so on. Certainly, other compression algorithms may also be adopted to compress the TIM, and are indicated by the compression method indication information.

For example, as shown inFIG. 6, when the compression method indication information is 001, which indicates adopting the multi-block compression algorithm, a value of the AID1 in the TIM message is one, and no other ones appear within seven bytes after the one; therefore, the block length is set to zero, which indicates that no bitmap exists after the one. In this way, the first basic element for compression is obtained. When a value of AID58 is one, because multiple ones appear within the range of seven bytes after the one, Bitmaps including the seven bytes of which values are ones in the TIM are copied into the block bitmap of the basic element, where the length (in bytes) of the block bitmap is indicated by the block length in the basic elements, and the block length of the second basic element is seven bytes. Then, the above steps are continuously performed to search for the first one that appears afterwards, and the above steps are repeated until the searching and encoding of the whole TIM is completed. After the whole TIM is compressed, multiple basic elements are obtained.

Meanwhile, as shown inFIG. 6, the transmitted traffic indication message further includes bit flipping indication information, used for indicating whether bit flipping is performed on the delivery traffic indication bit in the delivery traffic indication message.

The bit flipping is used to invert ones to zeroes and invert zeroes to ones before compression when multiple ones appear in the TIM, thereby further improving the compression efficiency. The flipping may be performed on the whole TIM before the compression; in this case, the bit flipping indication information needs to be added to the TIM message and may be placed behind the compression method indication information. When a value of the indication information is zero, it indicates that the flipping is not performed; and when the value of the indication information is one, it indicates that the flipping is performed before the compression. Correspondingly, the flipping may also be used for partial Bitmap compression, and may be indicated by a corresponding indication bit.

FIG. 7shows an information situation of the TIM before the bit flipping is performed, and an information situation of the TIM after the bit flipping is performed is shown inFIG. 6.

An embodiment of the present invention provides a method for receiving a traffic indication message. As shown inFIG. 8, operation steps of a terminal device include:

Step201: A first terminal device receives a traffic indication message, where the traffic indication message includes compression method indication information and a compressed delivery traffic indication message corresponding to at least one terminal device associated with an access point, the compression method indication information is used for indicating a compression method adopted to compress the delivery traffic indication message corresponding to the at least one terminal device, and the delivery traffic indication message indicates, through a delivery traffic indication bit, whether the at least one terminal device has data to receive.

Step202: According to the compression method indicated by the compression method indication information in the received traffic indication message, decompress the delivery traffic indication message in the received traffic indication message, and obtain the delivery traffic indication bit corresponding to the first terminal device.

In the method for receiving a traffic indication message provided by this embodiment of the present invention, the terminal device receives the traffic indication message, decompresses a delivery traffic indication message corresponding to the terminal device in the received traffic indication message, and obtains the delivery traffic indication bit corresponding to the terminal device, thereby solving the problem that the TIM message is too long, reducing the length of a Beacon frame, and increasing the transmission efficiency.

In this specific application, according to the compression method indication information in the received traffic indication message, decompression is performed on the delivery traffic indication message in the received traffic indication message, that is, a bitmap of the delivery traffic indication bit is decoded.

A compression algorithm indicated by the compression method indication information is shown inFIG. 6. According toFIG. 6, decompression is performed on the delivery traffic indication message corresponding to the terminal device in the received traffic indication message, that is, the bitmap of the delivery traffic indication bit is decoded.

Meanwhile, according to bit flipping indication information in the received traffic indication message, it is learned that whether bit flipping needs to be performed on the delivery traffic indication bit in the delivery traffic indication message.

As shown inFIG. 6, when the bit flipping indication information is one, bit flipping is performed on the obtained Bitmap after the decompression is performed on the received delivery traffic indication message according to the compression algorithm indicated by the compression method indication information, so as to invert ones to zeroes and invert zeroes to ones, and thereby corresponding delivery traffic indication information is obtained.

An embodiment of the present invention provides a method for transmitting a traffic indication message. As shown inFIG. 9, specific steps are as follows:

Step301: Group all terminal devices associated with an access point according to a preset number, and obtain at least one terminal device group.

The access point groups the terminal devices according to a preset fixed number.

For example, when the preset fixed number is 1500, every 1500 terminal devices form one group; therefore, terminal devices of which association IDs are from one to 1500 belong to a first terminal device group, terminal devices of which association IDs are from 1501 to 3000 belong to a second terminal device group, terminal devices of which association IDs are from 3001 to 4500 belong to a third terminal device group, and the rest can be deduced by analogy.

Step302: Compress a delivery traffic indication message corresponding to the at least one terminal device group, and generate a traffic indication message corresponding to the at least one terminal device group, where the delivery traffic indication message is corresponding to one terminal device in the at least one terminal device group, and the at least one terminal device associated with the access point is specifically any terminal device in the terminal device group corresponding to the traffic indication message.

Different compression methods may be adopted to compress a delivery traffic indication messages corresponding to terminal devices in each terminal device group, and a compression method is indicated by compression method indication information in the traffic indication message corresponding to the terminal device group.

Step303: Sequentially transmit the traffic indication message corresponding to the at least one terminal device group, where the traffic indication message further includes group information, the group information is group information used for indicating the terminal device group corresponding to the traffic indication message, and the delivery traffic indication message indicates, through a delivery traffic indication bit corresponding to each terminal device in the terminal device group corresponding to the delivery traffic indication message, whether each terminal device in the terminal device group corresponding to the delivery traffic indication message has data to receive.

The access point transmits a traffic indication message corresponding to an ithterminal device group to all the terminal devices which access the access point. The group information in the traffic indication message may include a group period of the terminal device groups, and/or the number of terminals included in each terminal device group, a group index i, compression method indication information, and the compressed delivery traffic indication message corresponding to each terminal device in the terminal device group, where i is a positive integer, and 1≦i≦group period.

In this case, the traffic indication message corresponding to the terminal device group is GTIM. A format of a first type of GTIM message provided by an embodiment of the present invention is shown inFIG. 10. Each GTIM message includes a DTIM message, and newly defined fields inFIG. 10are as follows: element ID indicates the type of a message, which is used for indicating that the message is a GTIM message; message length indicates the length of a transmitted GTIM message; compression method indication information indicates a method for compressing a delivery traffic indication message in a terminal device group; group period is used for indicating the total number of terminal device groups; and group index is used for indicating a group serial number of a terminal device group.

The group period and the group index may altogether occupy the first eight bits (each four bits) in an original partial virtual bitmap, and the compression method may occupy two or three bits in the original partial virtual bitmap; therefore, the partial virtual bitmap in the GTIM is reduced from the original 2008 bits to 1998 bits or 1997 bits, that is, the partial virtual bitmap may correspond to 1998 or 1997 terminal devices at most.

When the access point needs to support 6000 terminal devices, the preset fixed number is 1500; therefore, the group period is four. As the group period is four, the group index may be 1, 2, 3, or 4.

Because the traffic indication message corresponding to the terminal device group carries the delivery traffic indication message of the terminal device which accesses the access point, in the partial virtual bitmap, each bit is corresponding to a terminal device; when a message needs to be transmitted to a terminal device, a value of an indication bit corresponding to the terminal device is one; and when no message needs to be transmitted to the terminal device, the indication bit is zero. When plenty of zeroes exist, a great number of bits are wasted. An existing compression method is adopted to compress the delivery traffic indication message of each terminal device.

For example, when the compression method indication information takes up three bits, a compression method indicated by 000 is shown inFIG. 10; in the partial virtual bitmap, the first 16 bits (altogether two bytes) are all zeroes, and the rear bytes from the 501thbit to the last bit (altogether 125 bytes) are all zeroes; therefore, B7 in the Bitmap Control field is one, which indicates that two bytes are skipped, that is, AIDs in the partial virtual bitmap start from 16. The Length field is 128, because 256 bytes minus one byte of the Element ID is 255 bytes, and 255 bytes minus the skipped first two bytes and the truncated rear 125 bytes is 128 bytes. When the compression method is adopted, in a situation that a bit corresponding to AID1 is one, a bit corresponding to AID2007 is also one, and bits corresponding to all AIDs between AID1 and AID2007 are all zeroes, a beneficial effect of compression cannot be achieved.

In response to the above situation, a multi-block compression method algorithm may be adopted. As shown inFIG. 11, at this time, the compression method indication bit information is 001, and the seven bits in the Bitmap Control field and the partial virtual bitmap are replaced by the block basic elements shown inFIG. 6.

The traffic indication message corresponding to the terminal device group may include a plurality of the above basic elements, and the sizes of the basic elements are not fixed.

In addition, there may be other compression methods, which may provide different compression effects in different distribution situations of zeroes and ones in the delivery traffic indication messages corresponding to the terminal devices in each terminal device group. Therefore, in order to increase the compression efficiency, different compression methods may be adopted for different terminal device groups, so as to achieve the best compression effect.

Meanwhile, as shown inFIG. 10andFIG. 11, the transmitted traffic indication message corresponding to the terminal device group further includes bit flipping indication information, used for indicating whether bit flipping is performed on the delivery traffic indication bit in the delivery traffic indication message.

Beacon frames transmitted by the access point sequentially carry traffic indication messages corresponding to three terminal device groups in an order of group indexes of the terminal device groups, and the beacon frame transmitted each time carries a traffic indication message corresponding to one terminal device group.

Step304: Determine, according to the group information in the received traffic indication message, whether the received traffic indication message is the traffic indication message corresponding to the terminal device group to which the first terminal device belongs.

The first terminal device receives the traffic indication message corresponding to the ithterminal device group and transmitted by the access point. As described above, the group information in the traffic indication message may include a group period of the terminal device groups, and/or the number of terminal devices in each group, a group index i, compression method indication information, and the compressed delivery traffic indication message corresponding to each terminal device in the terminal device group, where i is a positive integer, and 1≦i≦group period.

It is determined whether the group index of the group to which the first terminal device belongs is equal to the group index of the ithterminal device group.

A group index of a terminal device group to which a terminal device belongs may be obtained by: dividing an association ID of the terminal device by a preset fixed number to obtain a quotient, rounding the quotient to obtain an integer, and adding one to the integer.

For example, the association ID of the first terminal device is 14, and the preset fixed number is 1500; therefore, the group index of the group to which the first terminal device belongs is [14/2000]+1, that is, the group index of the group, to which the first terminal device with the association ID being 14 belongs, is one.

Step305: When it is determined that the traffic indication message received by the first terminal device is the traffic indication message corresponding to the terminal device group to which the first terminal device belongs, according to the compression method indicated by the compression method indication information in the received traffic indication message, decompress the delivery traffic indication message in the received traffic indication message, and obtain the delivery traffic indication bit corresponding to the first terminal device.

When the group index of the group to which the first terminal device belongs is equal to the group index of the ithterminal device group, the delivery traffic indication message corresponding to the terminal device in the ithterminal device group is obtained.

For example, when the group index of the group, to which the first terminal device with the association ID being 14 belongs, is one, and the received traffic indication message is a traffic indication message corresponding to the first terminal device group, the terminal device obtains the delivery traffic indication message corresponding to the terminal device from the first terminal device group among the received terminal device groups.

Step306: When it is determined, according to the group information in the received traffic indication message, that the received traffic indication message is not the traffic indication message corresponding to the terminal device group to which the first terminal device belongs, continue to receive a traffic indication message corresponding to a next terminal device group; or predict, according to the group information in the received traffic indication message, a beacon frame of the traffic indication message corresponding to the terminal device group to which the first terminal device belongs, and obtain the beacon frame at the moment when the beacon frame is sent.

When the group index of the group to which the first terminal device belongs is not equal to the group index of the ithterminal device group, the first terminal device continues to receive a next beacon frame, where the next beacon frame includes a traffic indication message corresponding to an (i+1)thterminal device group; or when the group index of the group to which the first terminal device belongs is not equal to the group index of the ithterminal device group, the first terminal device predicts, according to the group period of the received terminal device groups, a beacon frame of the traffic indication message corresponding to the terminal device group to which the first terminal device belongs, and obtains the beacon frame at the moment when the beacon frame is sent.

For example, when the group index of the group, to which the first terminal device with the association ID being 4500 belongs, is three, and the received traffic indication message is a traffic indication message corresponding to the first terminal device group, the first terminal device is not in the received terminal device group. The first terminal device continues to receive a next beacon frame and executes step304; or when the first terminal device receives the first terminal device group and a group period four, the first terminal device may learn that the traffic indication message corresponding to the terminal device group to which the first terminal device belongs can be obtained from the third beacon frame to be transmitted later, so that the first terminal device does not need to wait to receive every beacon frame. In this way, energy saving of the terminal device is further implemented.

Step307: According to the compression method indicated by the compression method indication information in the received traffic indication message, decompress the delivery traffic indication message in the received traffic indication message, and obtain the delivery traffic indication bit corresponding to the first terminal device.

As shown inFIG. 10, when the AID of the first terminal device is 14, and the compression method indication bit received by the first terminal device is 000, according to an indication of B1-B7 in the Bitmap Control field, it is learned that the first 16 bits in the partial virtual bitmap are all zeroes, which indicates that the access point has no indication message to transmit to the first terminal device; therefore, the first terminal device does not perform any operation on the received traffic indication message corresponding to the terminal device group to which the first terminal device belongs.

As shown inFIG. 11, when the AID of the first terminal device is 14, and the compression method indication bit received by the first terminal device is 001, the first terminal device obtains, from a first block information basic element in the received traffic indication message corresponding to the terminal device group, an offset one and a block length zero, which indicates that the access point has no indication message to transmit to the first terminal device of which the AID is 14; therefore, the first terminal device does not perform any operation on the received traffic indication message.

When the AID of the first terminal device is one, and the compression method indication bit received by the first terminal device is 001, the first terminal device obtains, from the first block information basic element in the received traffic indication message corresponding to the terminal device group, an offset one, which indicates that the access point has an indication message to transmit to the first terminal device of which the AID is one; therefore, the first terminal device obtains the corresponding delivery traffic indication message.

In addition, there may be other compression methods, which may provide different compression effects in different distribution situations of zeroes and ones in the delivery traffic indication messages corresponding to the terminal devices in each terminal device group. According to different preset compression methods, corresponding decompression operations are performed to obtain the corresponding delivery traffic indication message.

In addition, when the obtained traffic indication message corresponding to the terminal device group to which the terminal device belongs includes bit flipping indication information, and the bit flipping indication information is one, bit flipping is performed on the Bitmap obtained after the decompression to invert ones to zeroes and invert zeroes to ones, so as to obtain the corresponding delivery traffic indication information, and thereby the delivery traffic indication message of the terminal device is obtained.

An embodiment of the present invention provides a method for transmitting a traffic indication message. As shown inFIG. 12, specific steps are shown in the following:

Step401: Group all terminal devices associated with an access point according to a preset number, and obtain at least one terminal device group.

The access point groups the terminal devices according to a preset fixed number.

For example, every 2000 terminal devices form one group; therefore, terminal devices of which association IDs are from 1 to 2000 belong to a first terminal device group, terminal devices of which association IDs are from 2001 to 4000 belong to a second terminal device group, terminal devices of which association IDs are from 4001 to 6000 belong to a third terminal device group, and the rest can be deduced by analogy.

The existing 2007 terminal devices may form the first terminal device group, and terminal devices of which association IDs are greater than 2007 may be grouped according to a preset fixed number.

Step402: Compress a delivery traffic indication message corresponding to the at least one terminal device group, and generate a traffic indication message corresponding to the at least one terminal device group, where the delivery traffic indication message is corresponding to one terminal device in the at least one terminal device group, and the at least one terminal device associated with the access point is specifically any terminal device in the terminal device group corresponding to the traffic indication message.

Different compression methods may be adopted to compress a delivery traffic indication message corresponding to terminal devices in each terminal device group, and a compression method is indicated by compression method indication information in the traffic indication message corresponding to the terminal device group.

Step403: Simultaneously transmit the traffic indication message corresponding to the at least one terminal device group, where the traffic indication message further includes group information, the group information is group information used for indicating the terminal device group corresponding to the traffic indication message, and the delivery traffic indication message indicates, through a delivery traffic indication bit corresponding to each terminal device in the terminal device group corresponding to the delivery traffic indication message, whether each terminal device in the terminal device group corresponding to the delivery traffic indication message has data to receive.

Specifically, traffic indication messages corresponding to all terminal device groups are included. When the first terminal device group includes the original 2007 terminal devices, the original TIM message format is adopted to transmit the traffic indication message corresponding to the terminal device group.

When the access point needs to support 6000 terminal devices, for terminal devices of which AIDs are greater than 2007, when the preset fixed number is 1999, these terminal devices are grouped and each group includes 1999 terminal devices, that is, terminal devices with AIDs from 2008 to 4007 form a group, and terminal devices with AIDs from 4008 to 6000 form another group. In this case, a second GTIM message format is adopted, and as shown inFIG. 13, newly defined fields are as follows: element ID indicates the type of a message, which is used for indicating that the message is a GTIM message; message length indicates the length of a transmitted GTIM message; group index is used for indicating a group serial number of a terminal device group and takes up eight bits; compression method indicates a method for compressing a traffic indication message in a terminal device group, and the compression method takes up two or three bits in a partial virtual bitmap; and Partial Virtual Bitmap supports at most 2014 or 2015 terminal devices.

Therefore, a beacon frame transmitted by the access point carries the original TIM message as well as a GTIM1 message and a GTIM2 message, where the group indexes of the GTIM1 message and the GTIM2 message are one and two, respectively.

For the partial virtual bitmap in each GTIM message, when the delivery traffic indication bit corresponding to each terminal device is zero, the GTIM message may not be sent.

Meanwhile, according to the indication of the compression method indication information, for example, the method shown inFIG. 10orFIG. 11, the terminal device group may compress the delivery traffic indication message corresponding to each terminal device in the traffic indication message corresponding to the terminal device group.

In addition, there may be other compression methods, which may provide different compression effects in different distribution situations of zeroes and ones in the delivery traffic indication messages corresponding to the terminal devices in each terminal device group. Therefore, in order to increase the compression efficiency, different compression methods may be adopted for different terminal device groups, so as to achieve the best compression effect.

Meanwhile, as shown inFIG. 10andFIG. 11, the transmitted traffic indication message corresponding to the terminal device group further includes bit flipping indication information, used for indicating whether bit flipping is performed on the delivery traffic indication bit in the delivery traffic indication message.

Step404: When the traffic indication message received by the first terminal device is a traffic indication message corresponding to at least two terminal device groups, obtain, according to the group information in the received traffic indication message, the delivery traffic indication message corresponding to the terminal device group to which the first terminal device belongs; and decompress, according to the compression method indicated by the compression method indication information in the received traffic indication message, the delivery traffic indication message in the received traffic indication message, and obtain the delivery traffic indication bit corresponding to the first terminal device.

For example, the traffic indication message corresponding to the terminal device group to which the terminal device belongs is obtained according to the association ID and the group index of the terminal device group.

The terminal device obtains the delivery traffic indication message corresponding to the terminal device from the decompressed delivery traffic indication messages corresponding to the terminal devices.

For a terminal device of which an association ID is greater than 2007, a group index of a terminal device group to which the terminal device belongs may be obtained by: subtracting 2007 from the association ID of the terminal device to obtain a value, dividing the obtained value by 1999 to obtain a quotient, rounding the quotient to obtain an integer, and adding one to the integer.

When the traffic indication message corresponding to the terminal device group to which the terminal device belongs is obtained, a corresponding decompression operation is performed according to the obtained compression method as shown inFIG. 10orFIG. 11.

In addition, when the obtained traffic indication message corresponding to the terminal device group to which the terminal device belongs includes bit flipping indication information, and the bit flipping indication information is one, bit flipping is performed on the Bitmap obtained after the decompression to invert ones to zeroes and invert zeroes to ones, so as to obtain the corresponding delivery traffic indication information, and thereby the delivery traffic indication message of the terminal device is obtained.

When the terminal device does not find the terminal device group to which the terminal device belongs in the received beacon frame, which indicates that the terminal devices in the group do not have data to transmit, the terminal device does not have data to receive.

An embodiment of the present invention provides an access point. As shown inFIG. 14, the access point includes a compressing unit501and a transmitting unit502, where the compressing unit501is configured to compress a delivery traffic indication message and generate a traffic indication message, where the delivery traffic indication message is used for indicating whether at least one terminal device associated with an access point has data to receive, and the delivery traffic indication message indicates, through a delivery traffic indication bit corresponding to the at least one terminal device, whether the at least one terminal device has data to receive; and the transmitting unit502is configured to transmit the traffic indication message, where the traffic indication message includes compression method indication information and the compressed delivery traffic indication message, and the compression method indication information is used for indicating a compression method adopted to compress the delivery traffic indication message.

In an embodiment, the compressing unit501is specifically configured to encode a bitmap of the delivery traffic indication bit.

In an embodiment, the traffic indication message transmitted by the transmitting unit502further includes bit flipping indication information, used for indicating whether bit flipping is performed on the delivery traffic indication bit in the delivery traffic indication message.

In an embodiment, as shown inFIG. 15, the compressing unit501further includes: a grouping module61configured to group all the terminal devices associated with the access point according to a preset number and obtain at least one terminal device group; a compressing module62configured to compress the delivery traffic indication message corresponding to the at least one terminal device group, and generate the traffic indication message corresponding to the at least one terminal device group, where the delivery traffic indication message is corresponding to one terminal device in the at least one terminal device group, and the at least one terminal device associated with the access point is specifically any terminal device in the terminal device group corresponding to the traffic indication message.

At this time, the transmitting unit is specifically configured to: transmit the traffic indication message corresponding to the at least one terminal device group, where the traffic indication message further includes group information, the group information is group information used for indicating the terminal device group corresponding to the traffic indication message, and the delivery traffic indication message indicates, through the delivery traffic indication bit corresponding to each terminal device in the terminal device group corresponding to the delivery traffic indication message, whether each terminal device in the terminal device group corresponding to the delivery traffic indication message has data to receive.

The transmitting unit is configured to sequentially transmit the traffic indication message corresponding to the at least one terminal device group; or simultaneously transmit the traffic indication message corresponding to the at least one terminal device group.

An embodiment of the present invention provides a terminal device. As shown inFIG. 16, the terminal device includes a receiving unit701and a decompressing unit702, where the receiving unit701is configured to receive a traffic indication message, where the traffic indication message includes compression method indication information and a compressed delivery traffic indication message corresponding to at least one terminal device associated with an access point, the compression method indication information is used for indicating a compression method adopted to compress the delivery traffic indication message corresponding to the at least one terminal device, and the delivery traffic indication message indicates, through a delivery traffic indication bit, whether the at least one terminal device has data to receive; and the decompressing unit702is configured to decompress, according to the compression method indicated by the compression method indication information in the received traffic indication message, the delivery traffic indication message in the received traffic indication message, and obtain the delivery traffic indication bit corresponding to the terminal device.

In an embodiment, the decompressing unit is specifically configured to decode a bitmap of the delivery traffic indication bit.

In an embodiment, the traffic indication message received by the receiving unit further includes bit flipping indication information, used for indicating whether bit flipping is performed on the delivery traffic indication bit in the delivery traffic indication message.

The traffic indication message received by the receiving unit may further include group information of the terminal device group. The group information is group information used for indicating the terminal device group, and the traffic indication message is corresponding to the terminal device group. The at least one terminal device associated with the access point is specifically any terminal device in the terminal device group corresponding to the traffic indication message.

In an embodiment, the receiving unit is specifically configured to: when the traffic indication message received by the receiving unit is a traffic indication message corresponding to one terminal device group, determine, according to the group information in the received traffic indication message, whether the received traffic indication message is the traffic indication message corresponding to the terminal device group to which the terminal device belongs; when it is determined that the traffic indication message received by the receiving unit is the traffic indication message corresponding to the terminal device group to which the terminal device belongs, decompress, according to the compression method indicated by the compression method indication information in the received traffic indication message, the delivery traffic indication message in the received traffic indication message; or when it is determined, according to the group information in the received traffic indication message, that the traffic indication message received by the receiving unit is not the traffic indication message corresponding to the terminal device group to which the terminal device belongs, continue to receive a traffic indication message corresponding to a next terminal device group; or predict, according to the group information in the received traffic indication message, a beacon frame of the traffic indication message corresponding to the terminal device group to which the terminal device belongs, and obtain the beacon frame at the moment when the beacon frame is sent.

In an embodiment, the receiving unit is specifically configured to: when the traffic indication message received by the receiving unit is the traffic indication message corresponding to at least two terminal device groups, obtain, according to the group information in the received traffic indication message, the delivery traffic indication message corresponding to the terminal device group to which the terminal device belongs; and decompress, according to the compression method indicated by the compression method indication information in the received traffic indication message, the delivery traffic indication message in the received traffic indication message.

An embodiment of the present invention provides a system for transmitting a traffic indication message. As shown inFIG. 17, the system includes an access point801and a terminal device802, where the access point801may be the access point composed of the compressing unit501and the transmitting unit502shown inFIG. 14, or composed of the compressing unit including the grouping module61and the compressing module62shown inFIG. 15and the transmitting unit502shown inFIG. 14; and the terminal device802may be the terminal device composed of the receiving unit701and the decompressing unit702shown inFIG. 16.

In the apparatus and system for transmitting a traffic indication message provided by the embodiments of the present invention, the access point groups the terminal devices to obtain the at least one terminal device group, compresses, according to the preset compression method, the delivery traffic indication message corresponding to each terminal device in the traffic indication message corresponding to the terminal device group, and transmits the traffic indication message which includes the compressed delivery traffic indication message, where the adopted transmitting manner includes: sequentially transmitting the traffic indication message corresponding to the at least one terminal device group or simultaneously transmitting the traffic indication message corresponding to the at least one terminal device group. In this way, when a single AP supports more than 2007 STAs, a problem that a TIM message is too long is solved, the TIM message is effectively compressed, and the length of the TIM message is reduced; therefore, the length of a beacon frame is reduced, and the transmission efficiency is increased.

The above method, apparatus, and system are more applicable to application scenarios where the number of terminal devices, such as smart meters and machine to machine (M2M) is large and the amount of data is small, so that a single AP supports more terminal devices in these application scenarios.

The technologies, system, apparatus, and method, respectively, illustrated in the above embodiments and the technical features, respectively, illustrated in the embodiments may be combined, so as to produce other modules, methods, apparatuses, systems, and technologies without departing from the spirit and principle of the present invention, and the modules, methods, apparatuses, systems, and technologies produced according to the embodiments of the present invention shall fall within the protection scope of the present invention.

Apparently, a person skilled in the art should understand that the units or steps in the present invention may be implemented by a universal computing apparatus. The units or steps may be integrated in a single computing apparatus, or may be distributed in a network composed of multiple computing apparatuses. Optionally, the units or steps may be implemented through program code which is executable to a computing apparatus, so that the units or steps may be stored in a storage device (such as a magnetic disk, an optical disc, a read-only memory, a random access memory, or a flash memory) to be executed by a computing apparatus. Alternatively, the units or steps may be, respectively, made into multiple circuit modules, or multiple units or steps in the units or steps may be made into a single circuit module so as to be implemented. Therefore, the present invention is not limited to any particular combination of hardware and software.