TWI734075B - Method of allocating protection duration of radio subsystem - Google Patents

Abstract

A method of allocating a protection duration of a radio subsystem for a transmitting station of a wireless communication system includes transmitting a proprietary frame to at least one receiving station of the wireless communication system, wherein the proprietary frame indicates the protection duration allocated for the radio subsystem.

Description

Method for allocating protection period of wireless subsystem

The present invention refers to a method of allocating the protection period of a wireless subsystem, and more particularly to a method of using a frame with a network allocation vector (NAV) to allocate the protection period of the wireless subsystem in a wireless communication system.

In a wireless communication system that complies with the IEEE 802.11 standard, the network allocation vector (NAV) is a timer mechanism that maintains the medium of the wireless communication system based on the period value information seen from the previous frame transmission. Forecasts on the future business. The network distribution vector can be regarded as a counter, which counts down to zero at a uniform rate. When the counter is not zero, the mobile station (STA) of the wireless communication system should not access the medium because the counter indicates that the system is busy.

In a coexistence scenario, for example, in a wireless communication system that can operate including the current wireless system (for example, WIFI) and another wireless subsystem (for example, Bluetooth), when it is determined that a short time is required to provide another wireless subsystem When in use, the sending station can send a frame with network allocation vector protection (NAV protection) to stop other interested mobile stations (for example, belonging to the same basic service set (BSS). ) Mobile station, also known as internal basic service set (intra-BSS) mobile station) transmission.

In this way, in terms of short-term protection, stopping the transmission from the mobile station of the internal basic service set is more effective than the power saving mechanism. However, this will result in reduced channel utilization because any mobile stations that have received NAV-protected frames (including non-interested mobile stations, for example, mobile stations belonging to another basic service set, also known as external basic services) Service Set (inter-BSS mobile station), they will update their network allocation vector and stop the transmission of another internal basic service set.

In view of this, the present invention provides a method for allocating the protection period of the wireless subsystem to the mobile station of the internal basic service set, which uses the frame with the network allocation vector to avoid reducing the channel utilization of the mobile station of the external basic service set. .

The present invention discloses a method for allocating the protection period of a wireless subsystem for a sending station of a wireless communication system. The method includes: sending a frame to at least one receiving station of the wireless communication system, wherein the frame indicates the wireless sub The protection period assigned by the system.

The present invention provides a method for allocating the protection period of a wireless subsystem for a receiving station of a wireless communication system. The method includes: receiving a frame from a transmitting station of the wireless communication system, wherein the frame indicates the wireless subsystem The assigned protection period.

When it is determined that the protection period needs to be allocated to the wireless subsystem, the present invention uses a dedicated frame to prohibit the internal basic service set mobile station from accessing the medium, but allows the external basic service set mobile station to access the medium. The dedicated frame indicates the basic service set identifier (receiving address) related to the sending station during the protection period. Therefore, when the receiving address matches the basic service set identifier of the receiving station, the receiving station can The network allocation vector is updated during the protection period indicated by the frame; otherwise, the receiving station discards the dedicated frame. In this way, through the method of allocating the protection period of the wireless subsystem of the present invention, it is possible to prevent the channel utilization rate of the uninterested station (for example, the mobile station of the external basic service set) from being reduced.

1: wireless communication system

3, 4: Process

30~32, 40~45: steps

Figure 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention.

Figure 2 is a schematic diagram of a transmission sequence according to the first embodiment of the present invention.

Figure 3 is a flow chart of the process of using the frame to allocate the protection period of the wireless subsystem to the mobile station in the internal basic service set according to the embodiment of the present invention.

FIG. 4 is a flowchart of a process of using a dedicated frame to allocate a protection period of a wireless subsystem to an internal basic service set mobile station according to an embodiment of the present invention.

Fig. 1 shows a wireless communication system 1 according to an embodiment of the present invention. The wireless communication system 1 includes basic service sets BSS1 and BSS2. The basic service set BSS1 includes the access point AP1 and mobile stations STA1~STA3, and the basic service set BSS2 includes the access point AP2 and mobile stations STA4~ to STA6.

Please note that mobile stations associated with the same access point are regarded as internal basic service set (abbreviated as intra-BSS) mobile stations, and stations associated with different access points are regarded as external basic service set (abbreviated as inter-BSS) mobile stations. -BSS) mobile station. For example, the mobile stations STA1~STA3 that access the access point AP1 are intra-BSS mobile stations of the basic service set BSS1, and the mobile stations STA4~STA6 that access the access point AP2 are the intra-BSS mobile stations of the basic service set BSS2. BSS mobile stations; and mobile stations STA1 and STA4 are inter-BSS mobile stations because they access different access points AP1 and AP2 respectively.

In the coexistence scenario in the basic service set BSS1, assume that the access point AP1 or mobile station STA1 determines that it is necessary to send a frame protected by a network allocation vector (NAV) to provide short-term use to the wireless subsystem (For example, Bluetooth). Based on the existing IEEE802.11 standard, since the mobile station STA4 can detect the NAV protected frame sent from the access point AP1 or the mobile station STA1, the mobile station STA4 as an inter-BSS mobile station will be prohibited from any transmission. In this case, the channel allocated to the mobile station STA4 to access the access point AP2 becomes idle, which causes the channel utilization rate of the basic service set BSS2 to decrease.

In order to avoid a decrease in channel utilization, the present invention uses a frame to prohibit intra-BSS mobile stations from accessing the medium when determining that the protection period needs to be allocated to the wireless subsystem, but allows inter-BSS mobile stations to access the medium. Specifically, in one embodiment, Table 1 illustrates the encoding of the "Duration/ID" field in the media access control (MAC) header format based on the IEEE 802.11 standard rule.

According to Table 1, when the most significant bit 15 is zero, the least significant bit 0-14 is used as the period in all frames except power-saving poll (PS-Poll) frames value. In other words, if a PS-Poll frame (ie, a regular-Poll frame) is received, the mobile station does not update its NAV value based on the "period/identification" field of the MAC header, because the PS-Poll frame is The "Period/Identification" field is used as the associated identifier of the relevant medium.

It can be seen from Table 1 that the PS-Poll frame can be used as a proprietary frame, which allows inter-BSS mobile stations to access the medium by not updating its NAV value, but through the “period/period” based on the MAC header. The least significant bit 0~14 of the “identification” field is used to update the NAV value of the intra-BSS mobile station to prohibit the intra-BSS mobile station from accessing the medium.

In one embodiment, if bit 15 of the "period/identification" field of the MAC header of the PS-Poll frame is zero, it is designated as a dedicated frame, and the protection period of the wireless subsystem can be set by the PS-Poll The least significant bit of the "period/identification" field of the MAC header of the frame is represented by 0~14.

When the mobile station wakes up from the power saving mode, it sends the PS-Poll frame to the access point to obtain the buffered frame when it is in the power saving mode. Therefore, the "basic service" of the MAC header of the PS-Poll frame The "Basic service set identifier" (BSSID) field is set to the receiver address (RA) of the basic service set to which it belongs, that is, the address of the access point currently associated with the sending station.

Please note that inter-BSS mobile stations and intra-BSS mobile stations are designated according to the basic service set identifier of the basic service set they belong to, so the receiving station will identify itself according to the basic service set identifier indicated by the PS-Poll frame It is an inter-BSS mobile station or an intra-BSS mobile station.

In one embodiment, the sending station can use the following rules to indicate it in the PS-Poll frame according to the "From DS" (distribution system, DS for short) field and the "To DS" field of the MAC header: Basic service set identifier: if "From DS" = 1 and "To DS" = 0, then the sending address is the basic service set identifier; or if "From DS" = 0 and "To DS" = 1, then receive The address is the basic service set identifier. The condition "From DS" = 1 and "To DS" = 0 means that the transmitted frame is sent from the distribution system (for example, the access point) to the mobile station, so the transmitter address (TA) is Set as the basic service set identifier. The condition "From DS"=0 and "To DS"=1 refers to the situation of the transmitted frame from the mobile station to the distribution system, so the receiver address is set as the basic service set identifier.

Therefore, when the PS-Poll frame is used as a dedicated frame, the receiving station that listens to the dedicated frame can know whether they are interested stations according to the basic service set identifier and the "receiving address" field of the MAC header. In one embodiment, when a dedicated frame is received, if the receiving address indicated by the dedicated frame matches the basic service set identifier of the basic service set to which it belongs, the intra-BSS mobile station can follow the protection period indicated by the dedicated frame Update its NAV value and stop accessing the medium until the NAV countdown is zero. On the other hand, when receiving a dedicated frame, if the receiver address indicated by the dedicated frame does not match the basic service set identifier of the basic service set to which it belongs, the inter-BSS mobile station can abandon the dedicated frame. avoid The channel utilization rate of inter-BSS mobile stations is reduced.

Please note that the sending station can send at least one of a beacon, a probe response, and an associated frame before sending a dedicated frame to indicate the capabilities of the wireless subsystem. A vendor specific information element (vendor specific information element) indication. Therefore, the transmission of any mobile station that is not interested and conforms to the existing IEEE 802.11 standard is not affected by the dedicated frame, because the dedicated frame is used as a regular PS-Poll frame to be discarded, so that it can avoid the uninteresting station's transmission. Channel utilization is reduced.

Figure 2 is a schematic diagram of a transmission sequence according to the first embodiment of the present invention. In the coexistence scenario of the basic service set BSS1, it is assumed that the access point AP1 or the mobile station STA1 determines that the current wireless system (for example, WIFI) needs to provide a short-term use for the wireless subsystem (for example, Bluetooth). The access point AP1 or the mobile station STA1 can send a frame, where the frame indicates the protection period allocated by the wireless subsystem, and the protection period includes the protection lead time and the operating time of the wireless subsystem. The frame can be a dedicated frame or a frame defined by a standard.

The access point AP1 and the mobile station STA1 can switch from the current wireless system operation to the wireless subsystem operation during the protection lead time; then the access point AP1 and the mobile station STA1 can perform the wireless subsystem operation during the wireless subsystem operation. At the same time, intra-BSS mobile stations STA2 and STA3 that listen to the dedicated frame can update their NAV values according to the protection period indicated by the dedicated frame to prohibit access to the access point AP1. The mobile station STA4 between the BSSs or any uninteresting stations (for example, the access point AP2 and the mobile stations STA5 and STA6) can discard the dedicated frame. In this way, it is possible to avoid reducing the channel utilization of any uninterested mobile stations.

FIG. 3 is a flowchart of process 3 of using a frame to allocate the protection period of the wireless subsystem to the intra-BSS mobile station according to an embodiment of the present invention. The frame can be a dedicated frame or a frame defined by a standard. Process 3 can be used for a sending station, which can be a mobile station or an access point in the basic service set of a wireless communication system. It prohibits intra-BSS mobile stations from accessing the medium but allows inter-BSS mobile stations to access the medium. Avoid reducing the channel utilization of inter-BSS mobile stations. Process 3 includes the following steps.

Step 30: Start.

Step 31: When it is determined that the protection period is allocated to the wireless subsystem in the wireless communication system, a dedicated frame is sent, where the dedicated frame indicates the protection period allocated for the wireless subsystem.

Step 32: End.

According to process 3, when it is determined that the wireless system in the wireless communication system allocates the protection period to the wireless subsystem, the sending station may send a dedicated frame, where the dedicated frame indicates the protection period allocated to the wireless subsystem. For a detailed description of the process 3, please refer to the related descriptions in Figure 1 and Figure 2, which will not be repeated here.

FIG. 4 is a flowchart of process 4 of using a dedicated frame to allocate a protection period of a wireless subsystem to an intra-BSS mobile station according to an embodiment of the present invention. Process 4 is used for a receiving station, which can be a mobile station or an access point in the basic service set of a wireless communication system. It prohibits intra-BSS mobile stations from accessing the medium but allows inter-BSS mobile stations to access the medium. Avoid reducing the channel utilization of inter-BSS mobile stations. Process 4 includes the following steps.

Step 40: Start.

Step 41: When it is determined that the protection period is allocated to the wireless subsystem in the wireless communication system, a dedicated frame is received, where the dedicated frame indicates the protection period allocated for the wireless subsystem.

Step 42: Check whether the receiver address indicated by the dedicated frame corresponds to its own basic service Set identifier matches. If it matches, proceed to step 43; if it does not match, proceed to step 44.

Step 43: Update the NAV value according to the protection period indicated by the dedicated frame. Go to step 45.

Step 44: Abandon the dedicated frame. And proceed to step 45.

Step 45: End.

According to process 4, when it is determined that the wireless system in the wireless communication system allocates the protection period to the wireless subsystem, the receiving station can receive a dedicated frame, where the dedicated frame indicates the protection period for the wireless subsystem. If the receiver address indicated by the dedicated frame matches its own basic service set identifier, the receiving station can update the NAV value according to the protection period indicated by the dedicated frame; otherwise, the receiving station discards the dedicated frame. For a detailed description of the process 4, please refer to the related descriptions of Figure 1 and Figure 2, which will not be repeated here.

In addition, in one embodiment, it is feasible to modify the current IEEE 802.11 standard to include the specification of the external basic service set protection frame. For example, a new MAC frame format can be added to the external basic service set protection frame. In another example, a new physical signal (physical signal, PHY SIG) field may be defined, or may include the protection period and the external basic service set indication, in which the payload of the external basic service set protection frame can be omitted ( payload) and reuse the external basic service set indication (for example, the "Basic Service Set Color" (BSS color) field specified in the IEEE 802.11ax standard). The "Basic Service Set Color" field is the identifier of the basic service set that sends the corresponding frame. During the carrier sensing process, all stations within the listening distance of the frame preamble read the basic service set color. Therefore, they can identify the basic service set for frame transmission. For example, if the basic service set identifier indicated by the "basic service set color" field is the same as the basic service set identifier of the receiving station, the dedicated frame is regarded as an external basic service set frame, or if the If the basic service set identifier indicated by the “service set color” field is different from the basic service set identifier of the receiving station, the dedicated frame is regarded as an external basic service set frame.

In summary, when it is determined that the protection period needs to be allocated to the wireless subsystem, the present invention uses a frame to prohibit intra-BSS mobile stations from accessing the medium, but allows inter-BSS mobile stations to access the medium. The frame can be a dedicated frame or a frame defined by a standard. The frame can indicate the basic service set identifier (receiver address) currently associated with the sending station during the protection period. Therefore, if the receiver address indicated by the frame matches the basic service set identifier of the receiving station, the receiving station can Update its NAV value according to the protection period indicated by the frame; otherwise, the receiving station discards the frame. In this way, it is possible to avoid reducing the channel utilization of any uninteresting stations. The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention should fall within the scope of the present invention.

3: process

30, 31, 32: steps

Claims (16)

A method for allocating a protection period of a wireless sub-system to a transmitting station of a wireless communication system includes: sending a frame to at least one receiving station of the wireless communication system, wherein the frame indicates the allocation to the wireless sub-system During the protection period of the system, if the receiver address indicated by the frame matches the basic service set identifier of the receiving station, the receiving station updates its network allocation vector ( network allocation vector (NAV) value, otherwise, the receiving station discards the frame. For example, the method described in item 1 of the scope of the patent application further includes: sending at least one of a beacon, a probe response, and an associated frame to the receiving station to indicate the capability of operating the wireless subsystem, wherein the capability is determined by the letter. A vendor specific information element (vendor specific information element) indication in at least one of the logo, the detection response, and the associated frame. The method described in item 1 of the scope of patent application, wherein if the bit of the "period/identification" field of the media access control (MAC) header of the PS-Poll frame is If yuan 15 is zero, the frame is designated as a dedicated frame. The method described in item 3 of the scope of patent application, wherein the protection period of the wireless subsystem is determined by the least significant bit of the "period/identification" field of the media access control header of the PS-Poll frame 0~14 indication. For example, the method described in item 3 of the scope of patent application, wherein the dedicated frame indicates the basic service set identifier (BSSID) of the sending station, if the PS-Poll frame is If the "From DS" field and the "To DS" field of the media access control header are 1 and 0 respectively, the sender address indicated by the dedicated frame is set as the basic service set identifier; if The “From DS” field and the “To DS” field of the media access control header of the PS-Poll frame are 0 and 1, respectively, and the receiver address indicated by the dedicated frame is set to this The basic service set identifier of the sending station. The method described in item 1 of the scope of patent application, wherein the protection period includes protection lead time and operation time. The method described in item 1 of the scope of patent application, wherein, if the basic service set identifier of the sending station indicated by the "basic service set color" field of the frame is the same as the basic service set identifier of the receiving station , The frame is an internal basic service set frame; or if the basic service set identifier of the sending station indicated by the "Basic Service Set Color" field is different from the basic service set identifier of the receiving station, then the The frame is an external basic service collection frame. A method for allocating a protection period of a wireless subsystem. The method is used in a receiving station of a wireless communication system. The method includes: receiving a frame from a sending station of the wireless communication system, wherein the frame indicates the allocation to the wireless During the protection period of the subsystem, if the receiver address indicated by the frame matches the basic service set identifier of the receiving station, the receiving station updates its network allocation vector according to the protection period indicated by the frame (network allocation vector, NAV) value, otherwise, the receiving station discards the frame. The method described in item 8 of the scope of patent application also includes: At least one of a beacon, a probe response, and an associated frame is received from the sending station to indicate the ability to operate the wireless subsystem, wherein the capability is determined by the supplier of at least one of the beacon, probe response, and associated frame Vendor specific information element indication. Such as the method described in item 8 of the scope of patent application, wherein, if bit 15 of the “period/identification” field of the media access control header of the PS-Poll frame is zero, the The frame is designated as a dedicated frame. The method described in claim 10, wherein the protection period of the wireless subsystem is determined by the least significant bit of the "period/identification" field of the media access control header of the PS-Poll frame 0~14 indication. For example, the method described in item 10 of the scope of patent application, wherein the dedicated frame indicates the basic service set identifier (BSSID) of the sending station, if the media access control of the PS-Poll frame The "From DS" field and the "To DS" field of the header are 1 and 0 respectively, and the transmitter address indicated by the dedicated frame is set as the basic service set identifier; if the PS-Poll message The "From DS" field and the "To DS" field of the MAC header of the frame are 0 and 1, respectively, and the receiver address indicated by the dedicated frame is set to the basic service set identification of the sending station symbol. For example, the method described in item 10 of the scope of patent application further includes: if the basic service set identifier of the receiving station is the same as the basic service set identifier of the sending station indicated by the dedicated frame, then according to the dedicated frame instruction Update the network allocation vector value during the protection period; or If the basic service set identifier of the receiving station is different from the basic service set identifier of the sending station indicated by the dedicated frame, the dedicated frame is discarded. Such as the method described in item 8 of the scope of patent application, wherein the protection period includes protection lead time and operation time. The method described in item 8 of the scope of patent application, wherein, if the basic service set identifier of the sending station indicated by the "basic service set color" field of the frame is the same as the basic service set identifier of the receiving station , The frame is an internal basic service set frame; or if the basic service set identifier of the sending station indicated by the "Basic Service Set Color" field is different from the basic service set identifier of the receiving station, then the The frame is an external basic service collection frame. For example, the method described in item 15 of the scope of the patent application further includes: if the frame is an internal basic service set frame, updating the network allocation vector value according to the protection period indicated by the frame; or if the frame is If the frame of basic services is set outside the time, the frame is discarded.

Images