Source: https://patents.google.com/patent/US9693303B2/en
Timestamp: 2018-11-15 23:31:23
Document Index: 382361952

Matched Legal Cases: ['Application No. 60', 'art 11', 'art 11', 'art 11', 'art 11', 'art 11', 'art 11']

US9693303B2 - Method and apparatus for efficient addressing and power savings in wireless communications - Google Patents
Method and apparatus for efficient addressing and power savings in wireless communications Download PDF
US9693303B2
US9693303B2 US14684896 US201514684896A US9693303B2 US 9693303 B2 US9693303 B2 US 9693303B2 US 14684896 US14684896 US 14684896 US 201514684896 A US201514684896 A US 201514684896A US 9693303 B2 US9693303 B2 US 9693303B2
US14684896
US20150223163A1 (en )
A method and apparatus may be used for assigning groups of stations in wireless communications to one or more groups. Groups may be assigned by an access point (AP) based on information received from a station (STA). Group information may be signaled to each station and a group identifier may be indicated in a frame. The group information may be applied to a performance enhancement, for example power savings for the station, wherein the station enters a power saving mode on a condition that the station determines that it is not a member of the group.
This application is a continuation of U.S. patent application Ser. No. 14/162,251 filed on Jan. 23, 2014, which is a continuation of U.S. patent application Ser. No. 13/036,456 filed on Feb. 28, 2011, which issued on Jan. 28, 2014 as U.S. Pat. No. 8,639,257, which is a continuation of U.S. patent application Ser. No. 12/539,837, filed on Aug. 12, 2009, which issued on Mar. 1, 2011 as U.S. Pat. No. 7,899,462, which is a divisional of U.S. patent application Ser. No. 11/406,877, filed Apr. 19, 2006, which issued on Aug. 18, 2009 as U.S. Pat. No. 7,577,438, which claims the benefit of U.S. Provisional Patent Application No. 60/674,811, filed Apr. 25, 2005, the contents of which are incorporated by reference.
Frame aggregation and frame bursting are two proposed mechanisms for enhancing the performance of WLAN systems. Such mechanisms are under consideration for the 802.11n extension to the 802.11 WLAN standard, which will allow for higher throughput WLAN devices. Both TGnSync and WWISE proposals are considering various types of frame aggregation and frame bursting schemes.
A method and apparatus may be applicable to frame aggregation schemes, frame bursting schemes, and to frames that are not aggregated (i.e., those sent to a single receiver for example). The method and apparatus may not be restricted to power and battery savings, but may also be used for other performance enhancing purposes, such as for providing addressing scalability via simplified group addressing, for use in packet scheduler design or implementation, or for use in various radio resource management functionalities.
A method and apparatus may be used to assign STAs in wireless communications to one or more groups. Groups may be assigned by an access point (AP) based on information received from a station (STA). Group information may be signaled to each STA and a group identifier may be indicated in a frame.
A method and apparatus may be used for enabling power savings in wireless communications may assign the STAs in a system into a number of groups. Group information may be signaled to each STA and a group identifier may be indicated in a frame. A STA may enter a power saving mode on a condition that the STA determines that it is not a member of the group.
A method and apparatus may be used for enabling power savings in wireless communications may indicate a traffic direction in a frame. The traffic direction may indicate the frame destination. The STA may enter a power saving mode on a condition that the traffic is not directed to the STA.
The method and apparatus may be used to receive and decode a frame at a STA until the STA decodes a power saving indicator. The STA may enter a power saving mode on a condition that the power saving indicator indicates that the STA may use the power saving mode. The power saving indicator may be associated with group information.
The method and apparatus may be used to transmit timing information to a STA in a portion of a frame. The STA may enter a power saving mode based on the timing information. The STA may exit the power saving mode based on the timing information, and may receive and decode a portion of the frame after exiting the power saving mode.
The method and apparatus may be used to provide listening instructions for a frame. The listening instructions may include an indication of how much of a frame may be decoded by a STA that is not an intended receiver of the frame. The listening instructions may be included in the frame, which may be transmitted to a STA. The frame may be received at the STA and the listening instructions may be decoded. The frame may be decoded at the STA based on the listening instructions, wherein the STA may enter a power saving mode after decoding the portion of the frame indicated by the listening instructions.
The method and apparatus may be used to transmit a first frame from a STA to an AP, including a request from the STA to opt out of a transmission type. At least one second frame may be transmitted from the AP. The STA may receive the second frame and decode the transmission type of the second frame. The STA may enter a power saving mode on a condition that the transmission type of the second frame is the transmission type that the STA has opted out from.
The present invention proposes a new efficient scheme for group addressing of STAs, and can be used in WLAN headers with limited size. This group addressing scheme can be used by various performance enhancement functions, such as power saving, radio resource management, improving QoS (Quality of Service), and packet scheduling (packet scheduler design and implementation). It may also be used to uniquely identify the final traffic destination (e.g., the receiving WLAN STA) when the number of STAs is small enough. In a WLAN, efficient addressing can be achieved by having an AP (access point) organize the STAs it is servicing (e.g., those STAs that are associated with the AP) into different groups, with each group capable of containing multiple STAs. The terminology “Power Saving Groups”, “Station Groups”, or “Address Groups” can be used to refer to such groups.
While a WLAN STA is typically uniquely identified by its MAC address, performance enhancements and power savings can be achieved without the need to specify the full MAC address or parts of the MAC address of the STA. Instead, a “group address,” a “group identifier,” a “group indicator,” or a “group number” can be used to enable power savings. For example as shown in FIG. 3, assume that an AP 300 would like to organize the six STAs (302-312) that it is servicing into four groups. One possibility is for the AP 300 to assign STAs #1 (302) and #6 (312) to group 1, STA #2 (304) to group 2, STA #4 (308) and #5 (310) to group 3, and STA #3 (306) to group 4. It is also possible for the AP 300 to place one STA in multiple groups. In FIG. 3, STAs #5 (310) and #6 (312) both belong to groups 1 and 3.
The AP can belong to a default group (e.g., a fixed value) that all STAs are aware of (for example, a group that is identified by all 0's or all 1's; in FIG. 3, the AP belongs to group 0). A STA that has not yet been assigned into a group by the AP can assume that it is, by default, part of all possible groups (e.g., a STA belongs to every group until it has been assigned into a specific group). Also, within the specific context of Direct Link Setup or Direct Link Protocol (DLS or DLP), the AP may communicate to a STA the group ID it should use when talking directly to another STA (e.g., which could be the group that the other STA is assigned into) or alternatively a default group may be used for such purpose.
The information proposed for use in realizing power savings, in simplified or scalable addressing, in scheduling frames (scheduler implementations), for any radio resource management functions, or for any other performance enhancement functions, is generically referred to as “power saving group information”. The use of such information is not restricted to power savings, but can be used for other purposes, such as data scheduler implementations; grouping STAs with similar aggregation requirements (i.e., those frames that are likely to be aggregated together), similar data rate, similar power, or similar QoS requirements within the same group; and various radio resource management functions. Some or all frames usable by the WLAN can contain all or some pieces of the power saving group information within the frame header (PHY or MAC header), the body of the frame, or any previously sent frames (e.g., RTS/CTS, IAC/RAC, CF-Poll, or QoS-Poll). The power saving group information can consist of one or more of the following pieces of information.
As another example, when an AP sends data to STAs using an aggregated frame (e.g., when using MSDU aggregation, MPDU aggregation, PPDU aggregation, PPDU Bursting, MRMRA, or Multi-Poll), a bitmap value of 0110 indicates that the frame contains data for at least one STA in group 2 and at least one STA in group 3, and that the frame does not contain data for group 1 or group 4. It is noted that even though this example assumes four groups, any number of groups can be used and the bitmap is expanded to accommodate the number of groups used. Further, the number of groups used can be presented as a dynamic variable. The GPI can be contained within the frame header, the PHY header, the MAC header, the SIGNAL field (legacy SIGNAL, HT-SIG, or SIGNAL-N) of the PHY header the MAC header, the MRAD, an MMP, or any multi-poll frame.
In order to provide the GTI, the start time for each group within the frame (e.g., in the form of a time offset) is provided. This information is the time at or near which the first piece of data belonging to any STA within the group starts getting transmitted. In order to provide the GTI efficiently, instead of fully specifying (encoding) the individual group start times (or offset times), a base duration (i.e., base period) that applies to all groups can be used and a different fractional value to identify the start time (e.g., the time offset) can be used for each group. For example, assuming that the base duration is 16 time units, then by using two bits, the group start time could be encoded and communicated as the fraction ¾, which means that the group start time (e.g., the group time offset) is (¾×16=) 12 time units either from a reference point in time.
An example of using the timing information based on the Spoofed Duration (SD) and GTI coding is shown in FIG. 4. The GTI indicates when the STA should begin listening to the medium, and in FIG. 4 the coded GTI is given in ¼ intervals of the SD. The coding for the GTI used in FIG. 4 is described in Table 1. It is noted that while Table 1 describes the GTI coding in terms of the SD, any type of frame duration can be used to encode the GTI.
GTI value When the STA begins listening
00 at the beginning of the SD
01 at ¼ of the SD
10 at ½ of the SD
11 at ¾ of the SD
Again taking the example of a GPI of 0110 indicating that groups 2 and 3 are present, one possible way to encode the GTI is to have two bits per group, so the GTI consists of eight bits (b1, b2, b3, b4, b5, b6, b7, b8), whereby the value of bits b1 and b2 provide the numerator value for group 1 (which may not be necessary in this example, since GPI indicates that group 1 is not present), while b3 and b4 provide the numerator value for group 2, and so on. As an example, in order to obtain the time offset information at or near which group 2's transmission will start, one has to multiply the base duration by the value of ‘b3 b4’ and divide by four. The time offset information is generally interpreted as the time at or near which a STA will start listening to the frame, when such frame contains data for that STA (i.e., when the STA's group is present within the frame).
GPTI value When the STA begins listening
11 at the end of the SD
In a system where there are multiple APs that may use the same frequency channel, it is possible for STAs within a given cell (i.e., an AP coverage area) to listen to frame transmissions occurring in another nearby or adjacent cell. In order to extract better power savings performance in such cases, the WLAN frame can contain an AP identification, which can be referred to as an “AP color” or “AP Group” or “Cell Color” or “Cell ID”. The AP color (APC) is not necessarily a unique identification of the AP. For example, if AP1, AP2, and AP3 are close to each other and are using the same frequency channel, then by using two bits to identify APC, AP1 can be assigned a color of 11, AP2 a color of 01, and AP3 a color of 00. The APC can be contained within the frame header, the PHY header, the MAC header, the SIGNAL field (legacy SIGNAL, HT-SIG or SIGNAL-N) of the PHY header, the MRAD, the MMP, or any multi-poll frame.
Power savings may also be obtained by knowing the direction of the traffic. For example, if a given STA is sending traffic to the AP, it marks in the frame header that the data is destined to the AP. STAs can use this information to achieve power savings since they can sleep during other STA's transmissions to the AP, by looking at this “traffic direction” (TD) field or bit. Within the MAC header, and more specifically within the Frame Control field of the MAC header, there are “To DS” and “From DS” fields that can be used to identify the direction of the traffic. Such information can also be used for the purpose of achieving power savings. Additionally, a new TD field can be located in the PHY header of the frame for the specific purpose of identifying the direction of the traffic. The TD field can be located within the SIGNAL field (legacy SIGNAL, HT-SIG, or SIGNAL-N) of the PHY header. The advantage of this simple scheme is that it does not require specific new signaling to establish the groups (one group consists of the AP as the receiver, while the other group consists of all STAs as receivers).
1. A wireless station (STA) comprising:
a transmitter configured to transmit information to an access point (AP);
a receiver configured to receive, from the AP, a management frame that includes an indication of a plurality of groups to which the STA is assigned;
wherein the transmitter is further configured to transmit, to the AP, an acknowledgement associated with the management frame;
wherein the receiver is further configured to receive a data frame, wherein the data frame comprises a data packet and a group identifier; and
a processor configured to determine whether the group identifier received in the data frame corresponds to at least one of the plurality of assigned groups, and wherein the processor is further configured to cause the STA to enter a power saving mode on a condition that the group identifier received in the data frame does not correspond to at least one of the plurality of assigned groups.
2. The STA of claim 1, wherein the transmitter is further configured to transmit traffic utilization information to the AP.
3. The STA of claim 1, wherein the transmitter is further configured to transmit power level information to the AP.
4. The STA of claim 1, wherein the transmitter is further configured to transmit a quality of service requirement to the AP.
5. The STA of claim 1, wherein the assigned group is based on a load balancing requirement.
6. A method associated with a station (STA), the method comprising:
transmitting information to an access point (AP);
receiving, from the AP, a management frame that includes an indication of a plurality of groups to which the STA is assigned;
transmitting, to the AP, an acknowledgement associated with the management frame;
receiving a data frame, wherein the data frame comprises a data packet and a group identifier;
determining whether the group identifier received in the data frame corresponds to at least one of the plurality of assigned groups; and
causing the STA to enter a power saving mode on a condition that the group identifier received in the data frame does not correspond to at least one of the plurality of assigned groups.
7. The method of claim 6, further comprising transmitting traffic utilization information to the AP.
8. The method of claim 6, further comprising transmitting power level information to the AP.
9. The method of claim 6, further comprising transmitting a quality of service requirement to the AP.
10. The method of claim 6, wherein the assigned group is based on a load balancing requirement.
a receiver configured to receive information from at least one station (STA);
a processor configured to assign a STA to a plurality of groups based on the received information;
a transmitter configured to transmit, to the STA, a management frame that includes an indication of the plurality of groups to which the STA is assigned;
wherein the receiver is further configured to receive, from the STA, an acknowledgement associated with the management frame; and
wherein the transmitter is further configured to transmit, to the STA, a data frame including a data packet and a group identifier to enable the STA to determine whether the data packet is intended for at least one of the plurality of groups.
12. The AP of claim 11, wherein the receiver is further configured to receive traffic utilization information from each of a plurality of STAs and wherein the processor is further configured to assign the plurality of groups based on the traffic utilization information.
13. The AP of claim 11, wherein the receiver is further configured to receive power level information from each of a plurality of STAs and wherein the processor is further configured to assign the plurality of groups based on the power level information.
14. The AP of claim 11, wherein the receiver is further configured to receive a quality of service requirement from each of a plurality of groups and wherein the processor is further configured to assign the STA to the plurality of groups based on the received quality of service requirement.
15. A method associated with an access point (AP), the method comprising:
receiving information from at least one station (STA);
assigning a STA to a plurality of groups based on the received information;
transmitting, to the STA, a management frame that includes an indication of the plurality of groups to which the STA is assigned;
receiving, from the STA, an acknowledgement associated with the management frame; and
transmitting, to the STA, a data frame including a data packet and a group identifier to enable the STA to determine whether the data packet is intended for at least one of the plurality of groups.
16. The method of claim 15, further comprising receiving traffic utilization information from each of a plurality of STAs and assigning the plurality of groups based on the traffic utilization information.
17. The method of claim 15, further comprising receiving power level information from each of a plurality of STAs and assigning the plurality of groups based on the power level information.
18. The method of claim 15, further comprising receiving a quality of service requirement from each of a plurality of groups and assigning the STA to the plurality of groups based on the received quality of service requirement.
US14684896 2005-04-25 2015-04-13 Method and apparatus for efficient addressing and power savings in wireless communications Active 2026-09-07 US9693303B2 (en)
US67481105 true 2005-04-25 2005-04-25
US11406877 US7577438B2 (en) 2005-04-25 2006-04-19 Method and system for efficient addressing and power savings in wireless systems
US12539837 US7899462B2 (en) 2005-04-25 2009-08-12 Method and system for efficient addressing and power savings in wireless systems
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US14162251 US9042290B2 (en) 2005-04-25 2014-01-23 Method and apparatus for efficient addressing and power savings in wireless communications
US14684896 US9693303B2 (en) 2005-04-25 2015-04-13 Method and apparatus for efficient addressing and power savings in wireless communications
US15610714 US20170273021A1 (en) 2005-04-25 2017-06-01 Method and apparatus for efficient addressing and power savings in wireless communications
US14162251 Continuation US9042290B2 (en) 2005-04-25 2014-01-23 Method and apparatus for efficient addressing and power savings in wireless communications
US15610714 Continuation US20170273021A1 (en) 2005-04-25 2017-06-01 Method and apparatus for efficient addressing and power savings in wireless communications
US20150223163A1 true US20150223163A1 (en) 2015-08-06
US9693303B2 true US9693303B2 (en) 2017-06-27
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US14162251 Active US9042290B2 (en) 2005-04-25 2014-01-23 Method and apparatus for efficient addressing and power savings in wireless communications
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