阅读说明：本技术 无线网络的多接入点工作 (Multi-access point operation for wireless networks ) 是由 方永刚 于 2020-03-02 设计创作，主要内容包括：公开了与数字无线通信相关的方法、系统和设备,并且更具体地,公开了与站控多接入点传输和重传相关的技术相关的方法、系统和设备。在一个示例性方面中,一种无线通信方法包括：从第一网络节点和第二网络节点接收多网络节点能力指示消息,该消息指示第一网络节点和第二网络节点中的每个都能够传送多网络节点传输。该方法还包括向第一网络节点和第二网络节点传送多网络节点关联请求消息,以将第一网络节点和第二网络节点关联为网络节点组。(Methods, systems, and devices related to digital wireless communications are disclosed, and more particularly, methods, systems, and devices related to techniques related to station controlled multi-access point transmissions and retransmissions. In one exemplary aspect, a method of wireless communication includes: a multi-network node capability indication message is received from the first network node and the second network node, the message indicating that each of the first network node and the second network node is capable of transmitting a multi-network node transmission. The method also includes transmitting a multi-network node association request message to the first network node and the second network node to associate the first network node and the second network node as a network node group.)

1. A method for wireless communication, comprising:

receiving, by a station, a first indication message from a first network node indicating that the first network node is capable of communicating information with other network nodes of a set of network nodes and a second indication message from a second network node indicating that the second network node is capable of communicating information with other network nodes of the set of network nodes; and

transmitting, by the station, a first request message to the first network node to associate the first network node with a group of network nodes, and a second request message to the second network node to associate the second network node with the group of network nodes.

2. The method of claim 1, further comprising:

receiving, by the station, at least one of a first response message from the first network node and a second response message from the second network node, the first and second response messages indicating an acknowledgement that the at least one of the first and second network nodes is included in the group of network nodes.

3. The method of claim 2, further comprising:

transmitting, by the station, a multi-network node group acknowledgement message that indicates the station to identify the network node group as including acknowledgements of the first network node and the second network node.

4. The method of claim 1, wherein the first and second indication messages comprise multi-network node support information and hybrid automatic repeat request (HARQ) support information in an Extremely High Throughput (EHT) capability information element of a multi-network node capability indication message.

5. The method of claim 4, wherein the multi-network node support information comprises at least one of: information indicating that the second network node does not support multi-network node functionality, information indicating that the second network node supports selective multi-network node transmission, information indicating that the second network node supports joint multi-network node transmission, and information indicating that the second network node supports both selective multi-network node transmission and joint multi-network node transmission.

6. The method of claim 4, wherein the HARQ support information comprises at least one of: information indicating that the second network node does not support HARQ, information indicating that the second network node only supports Chase Combining (CC) HARQ, information indicating that the second network node only supports Incremental Redundancy (IR) HARQ, and information indicating that the second network node simultaneously supports CC HARQ and IR HARQ.

7. The method of claim 1, wherein the first request message includes a multi-network node group identifier that identifies the network node group.

8. The method of claim 2, wherein the first and second network nodes are configured to align the timing of the first and second network nodes with the timing associated with the station based on receiving the first request message.

9. The method of claim 1, further comprising:

transmitting, by the station, a multi-network node re-association request message to update the group of network nodes, wherein updating the group of network nodes includes adding a new network node or removing a network node from the group of network nodes.

10. The method of claim 2, further comprising:

starting, by the station, a timer to track a lifecycle of the group of network nodes upon receiving the multi-network node association response message from the first network node and the second network node.

11. The method of claim 10, further comprising:

and after the timer expires, releasing the network node group by the station.

12. The method of claim 1, further comprising:

transmitting, by the station, a disassociation message to all network nodes associated with the multi-network node group to release the network node from a multi-network node.

13. The method of claim 1, wherein the first network node and the second network node are interconnected via a switch through a Distribution System (DS) forming a multiple Basic Service Set (BSS).

14. A method for wireless communication, comprising:

transmitting, by a station, a first message to at least one of a first network node and a second network node in a group of network nodes, wherein the first message includes transmission configuration information; and

receiving, by the station, data from at least one of the first network node and the second network node in the multi-network node group based on the transmission configuration information.

15. The method of claim 14, wherein the transmission configuration information comprises a request for the first network node to transmit data on a first channel.

16. The method of claim 15, wherein the data is transmitted by the first network node via a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU), the PLCP PPDU comprising a plurality of aggregated media access control protocol data units (MPDUs).

17. The method of claim 14, wherein the transmission configuration information comprises a request for the first network node and the second network node to jointly transmit the data to the station, and wherein the data is received from the first network node and the second network node.

18. The method of claim 17, wherein the first network node transmits the data on a first channel, and wherein the second network node transmits the data on a second channel.

19. The method of claim 18, further comprising:

combining, by the station, the data transmitted by the first network node and the second network node in a Physical (PHY) baseband.

20. The method of claim 17, wherein the first network node transmits the data on a first channel, and wherein the second network node transmits the data on the first channel.

21. The method of claim 18, further comprising:

combining, by the station, the data transmitted by the first network node and the second network node in a Radio Frequency (RF) module.

22. A method for wireless communication, comprising:

receiving, by a first network node included in a group of network nodes, scheduling information from a controller that controls transmissions by the group of network nodes to schedule a time to transmit a request-to-send message to a station; and

transmitting, by the first network node included in the group of network nodes, the request to send message to the station at the time indicated by the controller based on the scheduling information.

23. The method of claim 22, wherein the request to send message is transmitted on a first channel, and wherein a second network node included in the group of network nodes is configured to transmit a second request to send message on a second channel.

24. The method of claim 22, wherein the request to send message is transmitted on a first channel, and wherein a second network node included in the group of network nodes is configured to transmit the second request to send message on the first channel.

25. The method of claim 22, further comprising:

receiving, by the first network node included in the group of network nodes, a clear to send message from the station, the clear to send message indicating a request for the first network node to transmit data to the station.

26. The method of claim 25, wherein the clear to send message is received by at least one other network node included in the group of network nodes.

27. The method of claim 22, wherein stations not included in the group of network nodes are configured to update a Network Allocation Vector (NAV) to prevent transmission of data during a transmit opportunity (TXOP) time period associated with the group of network nodes based on receiving the request to send message.

28. The method of claim 25, wherein the clear to send message comprises at least one of: a preferred multi-network node transmission type indicating one of a selective multi-network node transmission or a joint multi-network node transmission, a multi-network node transmission handover reservation for a joint multi-network node transmission, a hybrid automatic repeat request (HARQ) retransmission type indicating Chase Combining (CC) or Incremental Redundancy (IR), an identification of at least one network node in the group of network nodes, a Received Signal Strength (RSSI) measurement, and a preferred downlink transmission power on an operating channel.

29. A method for wireless communication, comprising:

receiving, by a station, a first message from a first network node included in a group of network nodes, wherein the station initiates formation of the group of network nodes;

determining, by the station, that an error exists in a portion of the first message; and

transmitting, by the station, a second message instructing the first network node to retransmit the request for the portion of the first message.

30. The method of claim 29, wherein the second message comprises a Media Access Control (MAC) header for a multi-network node control frame.

31. The method of claim 30, wherein the MAC header comprises a common information field, wherein the common information field comprises at least one of: an identifier identifying the group of network nodes, a Negative Acknowledgement (NACK) identifier indicating the error in the first message, a multi-network node type indicating a subsequent message to be transmitted in one of a joint multi-network node transmission or a selective multi-network node transmission, a multi-network node handover reservation indicating other network nodes in the group of network nodes to reserve Resource Units (RUs) and to perform data cache synchronization with other network nodes in the group, and a HARQ type to be used for a subsequent HARQ retransmission.

32. The method of claim 29, further comprising:

receiving, by the station, a third message comprising a portion of the first message that includes an error.

33. The method of claim 29, wherein the second message comprises a hybrid automatic repeat request (HARQ).

34. The method of claim 29, wherein a network node group controller is configured to schedule joint transmission of information included in the first message, the joint transmission of information being performed by each network node included in the network node group.

35. The method of claim 29, wherein the first message comprises a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU), the PLCP PPDU comprising a plurality of aggregated media access control protocol data units (MPDUs).

36. The method of claim 35, wherein the determining comprises checking whether there is an error in each MPDU received in the first message.

37. The method of claim 35, wherein the second message comprises a HARQ request for retransmission of at least one MPDU included in the first message.

38. The method of claim 35, wherein the second message comprises a HARQ request for retransmission of the PPDU on a second Resource Unit (RU) included in a control frame of a third message.

39. The method of claim 29, further comprising:

setting, by the station, a source address of the second message to an address of the station, a receive address of the second message to an address of the first network node included in the group of network nodes, and/or a destination address of the second message to an identifier associated with the group of network nodes, wherein the identifier associated with the group of network nodes is included in a common information portion of a Media Access Control (MAC) header of the second message.

40. The method of claim 32, wherein a second network node included in the group of network nodes is configured to receive the second message from the station and transmit a fourth message concurrently with transmitting the third message to the first network node, wherein the fourth message and the third message comprise the same MPDU identified in the second message.

41. The method of claim 32, wherein the third message is independently decodable by the station for the station to determine whether there is an error in the third message.

42. The method of claim 32, further comprising:

determining, by the station, that the third message does not include any errors; and

transmitting, by the station to the first network node, a fifth message acknowledging successful transmission of the third message.

43. The method of claim 34, wherein the network node group controller is a multi-basic service set (MBSS) controller configured to allow the network node to make subsequent multi-network node transmissions based on determining a TXOP time period during which the subsequent multi-network node transmissions are scheduled by the network nodes included in the network node group.

44. The method of claim 40, wherein the MPDU identified in the second message is jointly transmitted by the first and second network nodes in the third message and the first and second network nodes in the group of network nodes in the fourth message over a Resource Unit (RU) specified in the second message.

45. The method of claim 44, further comprising:

combining, by the station, the third message received in the joint transmission by the first network node and the second network node through one of the Radio Frequency (RF) module or a Physical (PHY) layer baseband; and

transmitting, by the station, the fourth message to the first network node and the second network node to identify any failed MPDUs transmitted in the first message and the third message.

46. The method of claim 29, wherein the second message comprises a Media Access Control (MAC) header for a multi-network node control frame.

47. A method for wireless communication, comprising:

receiving, by a station, a first message from a first network node included in a group of network nodes;

determining, by the station, that a portion of the first message includes an error; and

transmitting, by the station, a second message to a second network node included in the group of network nodes, wherein the second message includes a request to retransmit the portion of the first message that includes the error.

48. The method of claim 47, further comprising:

receiving, by the station, a third message from the second network node, wherein the third message comprises a portion of the first message that includes an error.

49. The method of claim 48, wherein the second message comprises an identifier identifying the group of network nodes, and wherein the second network node is configured to transmit the third message based on determining that the identifier matches the group of network nodes associated with the second network node.

50. The method of claim 47, wherein the first message comprises a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU), the PLCP PPDU comprising a plurality of aggregated media access control protocol data units (MPDUs).

51. The method of claim 50, wherein the second message comprises a hybrid automatic repeat request (HARQ) for retransmitting at least one MPDU identified in the first message.

52. The method of claim 50, wherein the second message comprises a bitmap corresponding to each MPDU transmitted in the first message, wherein the station is configured to update the bitmap based on identifying the errors in the MPDUs for the second network node to identify the MPDUs having the errors.

Technical Field

The present patent application relates generally to wireless communications.

Background

A wireless communication system may include a network of one or more Access Points (APs) in communication with one or more wireless Stations (STAs). The AP may transmit radio signals carrying management information, control information, or user data to one or more STAs. The STA may transmit radio signals to the AP in the same frequency channel using a technique such as Time Division Duplex (TDD), or in a different frequency channel using a technique such as Frequency Division Duplex (FDD).

Institute of Electrical and Electronics Engineers (IEEE)802.11 specifies a specification for a Wireless Local Area Network (WLAN) through a radio channel in an unlicensed frequency band. The basic element of a WLAN is the Basic Service Set (BSS). The infrastructure BSS may include a BSS having stations that connect to a wired network or the internet by associating with an Access Point (AP). In an infrastructure BSS, both the access point and the stations can share the same frequency channel for multiple access and data transmission via the use of carrier sense multiple access with collision avoidance (CSMA/CA) technology, a TDD mechanism.

Disclosure of Invention

Methods, systems, and devices related to digital wireless communications are disclosed, and more particularly, to methods, systems, and devices related to techniques for utilizing multiple access points to communicate user data to a station to improve transmission reliability.

In one exemplary aspect, a method of wireless communication includes: a multi-network node capability indication message is received from the first network node and the second network node, the message indicating that each of the first network node and the second network node is capable of transmitting a multi-network node transmission. The method further comprises the following steps: transmitting a multi-network node association request message to the first network node and the second network node to associate the first network node and the second network node as a network node group.

In another exemplary embodiment, a wireless communication method includes: a first message is transmitted to a first network node and a second network node in a multi-network node group, wherein the first message includes transport configuration information. The method further comprises the following steps: data is received from at least one of the first network node and the second network node in the group of network nodes based on the transmission configuration information.

In another exemplary embodiment, a method for wireless communication includes: scheduling information is received from the controller to schedule a time for transmission of the request-to-send message to the station. The method further comprises the following steps: transmitting a transmission request to the station at a time indicated by the controller based on the scheduling information.

In another exemplary embodiment, a method for wireless communication includes: a first message is received from a first network node included in a group of network nodes. The method further comprises the following steps: it is determined that an error exists in a portion of the first message. The method further comprises the following steps: transmitting a second message indicating the request to the first network node to retransmit the portion of the first message.

In another exemplary embodiment, a method for wireless communication includes: a first message is received from a first network node included in a group of network nodes. The method further comprises the following steps: it is determined that a portion of the first message includes an error. The method further comprises the following steps: transmitting a second message to a second network node included in the group of network nodes, wherein the second message includes a request to retransmit the portion of the first message that includes the error.

The details of one or more implementations are set forth in the accompanying drawings, and the description below. Other features will be apparent from the description and drawings, and from the claims.

Drawings

Fig. 1 shows an example infrastructure multi-bss (mbss).

FIGS. 2A-2B illustrate examples of selective transmission of MAP-G.

Fig. 3A-3B illustrate examples of joint transmission of MAP-G.

Fig. 4 illustrates an example signaling procedure 400 for MAP-G establishment based on association request and response messages.

Fig. 5A-5B illustrate example signaling procedures for MAP transmission protection establishment.

Fig. 6A-6B illustrate example signaling procedures for selective MAP transmission with HARQ retransmission and handover MAP.

Fig. 7 shows an example signaling process for a joint MAP transmission with HARQ retransmissions.

Fig. 8 shows an example of an EHT capability IE having MAP and HARQ support information.

Fig. 9 shows an example MAC header format for a MAP control frame.

Fig. 10A-10B illustrate examples of HARQ NACKs that identify failed MPDUs or HPDUs in a MAP PPDU.

Fig. 11 shows a block diagram of a method for controlling transmissions and retransmissions by a station-controlled multi-access point.

FIG. 12 is a block diagram representation of a portion of a hardware platform.

Detailed Description

Wireless local communication is rapidly becoming a popular mechanism to communicate with each other directly or through a network such as the internet. Multiple wireless devices (e.g., smartphones, tablets, etc.) may attempt to transmit and receive data over a shared communication spectrum in an environment (e.g., an airport, home, building, stadium, etc.). Furthermore, wireless devices (e.g., sensors, cameras, control units, etc.) are increasingly being used in networks for various applications (e.g., factory automation, vehicle communications, etc.).

In some cases, the data transmission is based on an air interface specified by the Institute of Electrical and Electronics Engineers (IEEE) standard 802.11 series. In this specification, devices may share a transmission medium that includes a particular set of rules. In IEEE802.11, a Basic Service Set (BSS) is a component of a Wireless Local Area Network (WLAN). Associated wireless stations (also referred to as stations) in the radio coverage area may establish a BSS and provide basic services of the WLAN.

IEEE802.11 specifies wireless access protocols that operate over unlicensed and/or shared spectrum. A station may operate on a channel in an unlicensed band (e.g., 2.4GHz or 5GHz) or a band shared with other traffic (e.g., 6 GHz).

When operating over unlicensed or shared spectrum, the transmission and reception of wireless messages may be unreliable due to interference from other sites located within the same coverage area (such as hidden node transmissions or "visible" nodes attempting to utilize a common communication medium for transmissions). These unreliable transmissions may result in lost packets being transmitted, longer transmission delays due to the use of Enhanced Distributed Channel Access (EDCA), and greater jitter in an unstable radio environment. Such unreliable transmission may also degrade user experience and limit the performance of applications that require low latency and high reliability over IEEE802.11 access networks.

In some cases, because the IEEE802.11 specification allows a station to associate with an access point, it may be more difficult for the station to receive reliable transmissions when there is interference around the associated access point.

This patent application describes techniques for improving transmission reliability in a WLAN network by implementing a mechanism to control station-controlled Multiple Access Point (MAP) transmissions utilizing hybrid automatic repeat request (HARQ) retransmissions over multiple channels.

Fig. 1 shows an example infrastructure multi-bss (mbss). The infrastructure may include multiple stations STA 1110 and STA 2112. Each station may be included within the coverage area of a first access point AP 1120 and a second access point AP 2122, which form an infrastructure BSS: BSS1 and BSS 2. Access points AP 1120 and AP 2122 may be interconnected by a Distribution System (DS) via switches to form a multi-bss (MBSS)100 coordinated via MBSS controller 150. MBSS controller 150 may include network functions located at the gateway of any AP in MBSS 100. In some embodiments, MBSS controller 150 may include a full MAC protocol stack or a partial MAC protocol stack if MBSS controller 150 is located at a gateway of the DS.

In some embodiments, a station with multiple radio frequencies (e.g., STA 1110) may operate on one or more channels (or OFDMA channels) in the same frequency band or different frequency bands. The station may associate with a plurality of access points (MAPs) in the coverage of the MBSS to form a MAP group (MAP-G). The MAP-G may include a station (e.g., STA 1110) and one or more APs (e.g., AP 1120). The MAP-G may include a site-centric group of multiple access points.

In some embodiments, MAP-G utilizes joint or selective transmission over one or more channels (or OFDMA channels) to improve downlink transmission reliability under control of the STA (e.g., STA 1110) and/or coordinated by MBSS controller 150. A joint downlink transmission may refer to two or more APs transmitting the same PPDU to a STA at the same time. The STA may combine the received signals in Radio Frequency (RF) or baseband to improve the signal-to-noise ratio (SINR) of the received signals, thereby improving the reliability of the transmission.

Selective downlink transmission may refer to either AP 1120, AP 2122, or both AP 1120, AP 2122 transmitting a downlink PPDU to the STA. The STA may selectively receive transmissions from AP 1120 or AP 2122.

In some embodiments, the STA may utilize a hybrid automatic repeat request (HARQ) mechanism to request retransmission from the AP 1120 in the MAP-G over one or more (OFDMA) channels to improve transmission reliability.

FIGS. 2A-2B illustrate examples of selective transmission of MAP-G. In a first embodiment as shown in fig. 2A, MAP-G selective transmission may include a first AP1 transmission and a second AP2 transmission, the first AP1 transmission being over a first channel CH1, the second AP2 transmission being over a second channel CH2, where each channel may be a normal channel or an OFDMA channel. In the present embodiment, the AP1 or the AP2 may simultaneously or selectively transmit the MAP PPDU through the channels (CH1, CH2) according to the request of the STA in the MAP-G. If the AP1 and the AP2 transmit the MAP PPDU at the same time, the STA in the MAP-G can selectively receive the best MPDU among a plurality of received MPDUs.

In a second embodiment as shown in fig. 2B, MAP-G selective transmission may include a first AP1 transmission and a second AP2 transmission, the first AP1 transmission being over a first channel CH1, the second AP2 transmission being over the same channel CH 1. Either AP1 or AP2 may transmit a MAP PPDU to the STA. Depending on the reception conditions, the STA in the MAP-G may control the selection of MAP transmission by transmitting an uplink control frame to the AP1 or AP2 to request selective MAP PPDU transmission.

Fig. 3A-3B illustrate examples of joint transmission of MAP-G. In a first embodiment as shown in fig. 3A, the joint MAP transmission may include a first AP1 operating on a first channel and a second AP2 operating on a second channel. CH1 and CH2 may be in the same or different channel bands. AP1 and AP2 may jointly transmit the same MAP PPDU through CH1 or CH 2. The STAs in the MAP-G may perform maximum rate combining between the received joint MAP PPDU transmissions in the baseband.

In a first embodiment as shown in fig. 3B, the joint MAP transmission may include AP1 and AP2 operating on the same channel, i.e., both AP1 and AP2 are on CH1 or CH 2. AP1 and AP2 may jointly transmit MAP PPDUs. The STAs in the MAP-G may combine the received joint MAP PPDU transmissions in a Radio Frequency (RF) module to improve the SINR of the received PPDU.

In some embodiments, station-controlled multi-AP transmission and HARQ retransmission may include forming a multi-AP group (MAP) to coordinate MAP transmission and HARQ retransmission in the downlink. MAP-G formation may be based on enhancements to existing association requests/responses or define a set of new messages for establishing MAP-G.

Fig. 4 illustrates an example signaling procedure 400 for MAP-G establishment based on association request and response messages. As shown in fig. 4, at steps 401A-401B, AP 1420 and AP 2422 may be MAP-capable access points. The access points 420, 422 may broadcast the MAP support information and HARQ support information in an Extremely High Throughput (EHT) capability information element of a beacon or in a probe response frame. In an embodiment, if the AP supports the MAP, the MAP support indication may be changed to a first value. Otherwise, the MAP support indication may be set to a second value. Similarly, if the AP supports HARQ, the AP may set the HARQ support indication to a third value. Otherwise, the AP may set the HARQ support indication to a fourth value.

In step 402, a station (e.g., STA 410) in the MBSS coverage area may examine the beacon or probe response frame and determine whether the neighboring AP is capable of supporting the MAP and HARQ features. If STA 410 determines that a neighboring AP (e.g., AP 2422) has MAP and/or HARQ capabilities, the station may send a MAP association request to APs 420, 422, where the MAP association request may include a request to form a MAP-G over a single working channel or multiple working channels. The STA 410 may include a MAP-G identifier (MAP-G ID) in association with a station identifier (STA ID) in the MAP association request. The MAP-G ID may be used to identify the MAP-G until it is released.

In step 403, upon receiving the MAP association request from the STA, the AP 1420 and the AP 2422 may process the MAP association request and transmit a MAP association response to confirm whether it can join the requested MAP-G through a single channel or through multiple channels sequentially or simultaneously. AP 1420 and/or AP 2422 include the MAP-G ID and other MAP-G information in the MAP association response. AP 1420 and/or AP 2422 may use the MAP association request message to adjust or refine the AP timing to align with the timing of STA 410 and control it to be less than the CP time of the OFDM symbol. AP 1420 and AP 2422 may then be ready for the next MAP transmission.

In step 404, the STA may send a MAP-ACK to acknowledge the MAP member joining the MAP-G.

After the MAP-G is formed, the STA may send a MAP reassociation request to update the MAP-G, such as adding a new AP or removing an existing AP. The AP in the MAP-G may respond with a MAP reassociation response.

Members of the MAP-G (i.e., the STA and the MAP) may set a timer to track the MAP-G lifecycle after the MAP-G is formed. If the timer expires, the MAP-G may be released. If the MAP-G member detects any activity in the MAP-G before the timer expires, it may reset the timer to maintain the life of the MAP-G.

In some embodiments, MAP-G may be released if the STA disassociates from all members of MAP-G via sending a disassociation request.

In some embodiments, controlling multi-AP transmissions and HARQ retransmissions by a station may include establishing MAP TXOP protection. When there is some buffered data for the STA, the MBSS controller may coordinate all MAP-G members to schedule a MAP-RTS to be sent to request establishment of a MAP TXOP for the downlink MAP transmission.

Fig. 5A-5B illustrate example signaling procedures for MAP transmission protection establishment. In the first embodiment as shown in fig. 5A, MAP transmission protection may be established when AP1 and AP2 of the MAP-G are on different channels. In the second embodiment as shown in fig. 5B, MAP transmission protection may be established when AP1 and AP2 of the MAP-G operate on the same channel.

In step 501, MBSS controller 150 may coordinate AP1 and AP2 in the MAP-G to schedule MAP-RTS transmissions to STAs. In the first embodiment in fig. 5A, both AP1 and AP2 may transmit MAP-RTS through CH1 and CH2, respectively. In the second embodiment in fig. 5B, either AP1 or AP2 or both AP1 and AP2 in MAP-G may transmit a MAP-RTS request over CH 1.

Meanwhile, the MBSS controller may coordinate to send downlink MAP data to all MAP-G members (i.e., AP1 and AP2) to prepare MAP transmissions to the STAs. AP1 and AP2 may then prepare MAP transmissions.

In step 502, after receiving a MAP-RTS request from one or more MAP-G members, the STA may send a MAP-CTS via CH1 or CH2, or both, to acknowledge and activate a MAP transmission with the requested MAP-G member. The STA and MAP may use MAP-RTS and MAP-CTS to establish a TXOP for the next MAP transmission. Other STAs receiving the MAP-RTS and/or MAP-CTS may set their NAVs to prevent data from being transmitted during the MAP TXOP period.

The STA may include information about the MAP transmission, such as a preferred MAP transmission type, in the MAP-CTS to immediately trigger the MAP transmission: selective MAP transmission or joint MAP transmission; a MAP transmission switch reservation for joint MAP transmission; HARQ retransmission type: HARQ or non-HARQ tracking combining (CC) or Incremental Redundancy (IR); identity of the AP in MAP-G; measuring the RSSI; a preferred downlink transmission power on an operating channel; requested transfer time, etc.

In some embodiments, the station-controlled multi-AP transmission and HARQ retransmission may include a selective MAP transmission.

Fig. 6A-6B illustrate example signaling procedures for selective MAP transmission with HARQ retransmission and handover MAP. In step 601, MBSS controller 150 may coordinate APs in the MAP-G to schedule MAP transmissions to the STAs and to send downlink MAP data to all MAP-G members (i.e., AP 1610 and AP 2620). AP 1610 in this example may transmit a MAP-RTS to establish a MAP TXOP and to secure MAP communications with STA 630. Other nearby non-MAP-G STAs that receive this MAP-RTS may set their NAVs to prevent interference with the MAP transmission.

In step 602, after receiving the MAP-RTS, the STA 630 may send a MAP-CTS to acknowledge the MAP TXOP establishment and indicate a preferred MAP transmission option for the next one or more transmissions, such as a preferred MAP transmission type, HARQ retransmission type, one or more AP IDs, and so on. Other nearby non-MAP-G STAs that receive the MAP-CTS may set their NAVs to prevent interference with the MAP transmission.

In step 603, the selected AP (e.g., AP 1610) may transmit a MAP-PPDU, which may include an aggregated MPDU (a-MPDU), to the STA 630 based on the preferred MAP transmission information in the MAP-CTS. The AP 1610 sets a MAP-G ID to an SA field and an STA address to an RA field in the MAC header.

In step 604, the STA 630 may perform error checking on the MAP-PPDU received from the AP 1610 or error checking on each received MPDU. If there is an error on the received MAP-PPDU (or single MPDU), the STA 630 may send a MAP non-acknowledgement message (MAP-NACK) to the AP 1610 to request retransmission of one or more failed MPDUs. The STA 630 may request the AP 1610 to send HARQ retransmitted PPDUs on one or more different RUs to avoid interference to certain particular RUs.

The STA 630 may set the Source Address (SA) to its address and set the Receive Address (RA) to the address of the MAP-G ID in the MAP-NACK. If a DA is present, the STA may set the Destination Address (DA) to the MAP-G ID. The STA 630 may set the MAP-G ID in the common information of the MAC header of the MAP-NACK frame. When the MAP-NACK message is designated to the MAP-G, if the MAP transmission reservation switching is being set, the AP 2620 in the MAP-G may be able to receive the MAP-NACK and perform transmission synchronization with the AP 1610 for the MAP transmission switching.

In step 605, the AP 1610 may retransmit one or more failed MPDUs of the MAP-PPDU to the STA 630 with setting the MAP-G ID to the SA field and the STA address to the RA field. The MAP-PPDU may be independently decoded for the STAs to perform error checking.

In step 606, STA 630 may apply soft decoding to check whether CC or IR can correct one or more errors in the previous decoding. If an error is still detected in the MAP-PPDU (or single MPDU) of a HARQ retransmission, the STA 630 may send a MAP-NACK to request another HARQ retransmission. If a failure is experienced in one or more consecutive HARQ retransmissions, the STA 630 may request a switch to a different AP in the MAP-G for HARQ retransmission in the MAP-NACK message if the STA 630 can detect that the AP 2620 in the MAP-G is idle and that a MAP TXOP has been reserved for MAP-G members to switch MAP transmissions.

In step 607, if the AP 2620 receives a MAP-NACK with a MAP-G ID matching its MAP-G, the AP may initiate HARQ retransmissions for one or more failed MPDUs in the MAP-PPDU.

In step 608, if the STA 630 does not receive a MAP-PPDU for HARQ retransmission within a given time, it may trigger a retransmission timeout. The STA 630 may send another MAP-NACK or report HARQ failure after multiple retries. If STA 630 receives the MAP-PPDU, it may apply soft decoding to check whether CC or IR can correct one or more errors in the previous decoding. If the error can be corrected in the HARQ retransmission, the STA 630 may send a MAP-ACK to confirm that the MAP-G member successfully made the MAP PPDU transmission.

After receiving the MAP-ACK, if more data is buffered for STA 630 and a MAP TXOP is allowed to be used to schedule another MAP transmission, MBSS controller 150 may coordinate to schedule another MAP transmission in the MAP TXOP.

In some embodiments, the station-controlled multi-AP transmission and HARQ retransmission may include a joint MAP transmission.

Fig. 7 shows an example signaling process for a joint MAP transmission with HARQ retransmissions. In step 701, MBSS controller 150 may coordinate APs 710, 720 in the MAP-G to schedule MAP transmissions to STAs 730. Either AP 1710 or AP 2720 or both may transmit a MAP ready to send (MAP-RTS), for example, to establish a MAP TXOP to protect MAP communications with STAs. MBSS controller 150 may coordinate to send downlink MAP data to all MAP-G members (i.e., AP 1710 and AP 2720). Other nearby non-MAP-G STAs that receive the MAP-RTS may set their NAVs to prevent interference with communications.

In step 702, after receiving the MAP-RTS, the STA (730) sends a MAP clear to send (MAP-CTS) to acknowledge the MAP TXOP establishment and indicate a preferred MAP transmission option, e.g., a preferred MAP transmission type, a HARQ retransmission type, and one or more AP IDs for one or more initial transmissions. The STA730 may set the MAP transmission type to 'joint MAP transmission' in the MAP-CTS for joint MAP transmission. Other nearby STAs that receive the MAP-CTS may set their NAVs to prevent interference with the MAP transmission.

In step 703, both AP 1710 and AP 2720 may transmit the same MAP-PPDU, which may consist of a-MPDUs, to STA 730. AP 1710 and AP 2720 may set a MAP-G ID as an SA field and an address of STA (730) as an RA field in a MAC header.

In step 704, the STA730 may combine the received signals from the AP 1720 and the AP 2730 in the RF baseband or the PHY baseband and perform error checking on the combined MAP-PPDU or on each MPDU. If STA730 is unable to correctly decode any MPDUs of the MAP-PPDU or a-MPDU, STA730 may send a MAP-NACK to request retransmission of one or more failed MPDUs. STA730 may request to send HARQ retransmissions on one or more different Resource Units (RUs) to avoid interference to certain particular RUs.

STA730 may set the Source Address (SA) to its address, the Receive Address (RA) to the MAP-G ID, and/or the Destination Address (DA) to the MAP-G ID in the MAP-NACK, if present. The STA730 may set the MAP-G ID in a common information field of a MAC header of the MAP-NACK frame.

In step 705, after receiving the MAP-NACK from the STA730, both the AP 1710 and the AP 2720 may adjust their timing to align with the STA and retransmit one or more failed MPDUs of the MAP-PPDU to the STA730 at the requested time via the designated RU. AP 1710 and AP 2720 may set a MAP-G ID as an SA field and an address of STA730 as an RA field in a MAC header of retransmission.

In step 706, STA730 may check whether CC or IR is able to correct one or more errors in previous decoding using joint MAP HARQ retransmission. If an error is still detected, the STA730 may send a MAP-NACK to request another HARQ retransmission or report a HARQ retransmission failure after multiple retries. If the error can be corrected in the joint MAP HARQ retransmission, the STA730 may send a MAP-ACK to confirm that the MAP-G member successfully made the MAP PPDU transmission.

After receiving the MAP-ACK, if more data is buffered for STA730 and a MAP TXOP is allowed to be used to schedule another MAP transmission, MBSS controller 150 may coordinate to schedule another MAP transmission in the MAP TXOP.

In some embodiments, the station-controlled multi-AP transmission and HARQ retransmission may include MAP and HARQ support information in an EHT capability Information Element (IE). The EHT capability IE may be carried in an EHT beacon or probe response frame to indicate the capabilities of the AP.

Fig. 8 shows an example of an EHT capability IE having MAP and HARQ support information. In fig. 8, an information element 800 may carry information of EHT capability information and multiband operation information. The EHT capability information 810 may include MAP support information 811 and HARQ support information 812.

The MAP support information 811 indicates a MAP capability supported by the AP, and may include at least one of: an indication that it does not support MAP, an indication that it only supports selective MAP transmission, an indication that it only supports joint MAP transmission, and an indication that it supports selective MAP transmission and joint MAP transmission.

The HARQ support information 812 may indicate HARQ capabilities supported by the AP, which may include at least one of: an indication that HARQ is not supported (i.e., only the conventional ARQ mechanism is supported), an indication that it only supports Chase Combining (CC) HARQ, an indication that it only supports Incremental Redundancy (IR) HARQ, and an indication that it supports both CC and IR HARQ at the same time.

Multiband information 820 may include information for the multiple channels on which the AP is operating. Example channels may include 2.4GHz, 5GHz, or 6GHz frequency bands.

Fig. 9 shows an example MAC header format for a MAP control frame. The MAC header format for the MAP control frame may include, for example, MAP NACK/ACK, MAP CTS, MAP management frame (e.g., MAP association request).

The MAC header may include a Frame Control (FC) to indicate the MAC frame type and other information about the frame. The MAC header may include the transmission duration of the frame. The MAC header may include any one of a Reception Address (RA), a Transmission Address (TA), and a Destination Address (DA). The DA may be set to the MAP-G ID for MAP transmission.

The MAC header may include a common information field. The common information field may include at least one of a MAP-G ID for identifying a MAP-G and a NACK IND for indicating that the frame is a MAP-NACK or a MAP-ACK. If NACK IND is set to MAP-ACK, the previous MAP transmission or retransmission is successful. Otherwise, there may be an error in the previous MAP transmission or retransmission. Another retransmission may be needed in CC or IR.

The common information field may include a MAP type indicating a MAP transmission type (selective or joint) to be used. In the case of joint MAP transmission, MAP-G members may be requested to jointly transmit a MAP PPDU after receiving the frame. Otherwise, the selected one or more MAP-G members may be requested to transmit a MAP PPDU.

The common information field may include a MAP handover reservation indicating whether other MAP-G members need to reserve one or more RUs and perform data cache synchronization with the active MAP-G member for preparing MAP member handover in selective MAP transmission.

The common information field may include a HARQ type indicating a HARQ type (i.e., non-HARQ, HARQ-CC, or HARQ-IR) to be used in HARQ retransmission.

The MAC header may include MAP information that carries information for a single AP in a MAP transmission. The MAP information may include at least one of: a MAP ID specifying a single AP for MAP transmission, a Resource Unit (RU) indicating a RU to be used for MAP transmission from the AP, and an RTT, wherein a STA in the MAP-G can specify a time at which the AP having the MAP ID starts MAP PPDU transmission using the Requested Transmission Time (RTT). The AP may adjust its timing clock upon receiving the frame and schedule a MAP PPDU transmission at that time according to the RTT value. The MAP information may include an ETP indicating an expected transmit power for the AP to transmit a MAP PPDU.

In some embodiments, the station-controlled multi-AP transmission and HARQ retransmission may include a HARQ NACK frame to identify the failed MPDU in the MAP PPDU.

Fig. 10 shows an example of HARQ NACK for identifying failed MPDUs in a MAP PPDU. The MAP-PPDU 1010 may be a PPDU format, which may include at least one of a PHY preamble 1020 and a MAP a-MPDU 1030, the PHY preamble 1020 including an L-STF, an L-LTF, an L-SIG, an RL-SIG, an HE-SIG-A, HE-STF, an HE-LTF, an EHT-SIG, etc., the MAP a-MPDU 1030 being a payload of the PPDU 1010. MAP a-MPDU 1030 may include MPDU delimiter 1031, MPDU 1032, and padding 1033.

The MAP-NACK 1090 may be a HARQ NACK frame indicating the location of the failed MPDU 1032 within the received MAP-PPDU 1010. The MAP-NACK 1090 may comprise a bitmap in which each bit is mapped to a received MPDU. If an error is detected in the received MPDU, the corresponding bit of the bitmap in the MAP-NACK may be set to 1 to indicate that the MPDU needs to be retransmitted. The NACK bitmap may be carried in a MAP-NACK frame.

The MAP HARQ retransmission mechanism may utilize MAC layer MPDU retransmission and PHY layer combining (CC or IR) to improve the reliability of the retransmission. The minimum unit of HARQ retransmission may be the size of an MPDU.

The MAP-PPDU 1010 may include a PHY preamble 1020 and a MAC payload including one or more a-MPDUs 1030 and padding.

The MAC payload may be partitioned into multiple HARQ PDUs by the PHY layer according to HARQ transmission requirements. The minimum unit of HARQ retransmission may be different from the MPDU size.

The HARQ PDU 1040 may include a HARQ header 1041 and an HPDU 1042.

The MAP-NACK 1090 may include a HARQ NACK frame indicating the location of the failed HARQ PDU 1040 in the received MAP-PPDU 1010. The MAP-NACK 1090 may comprise a bitmap in which each bit is mapped to a received HARQ PDU 1040. If an error is detected in the received HARQ PDU 1040, the corresponding bit of the bitmap in the MAP-NACK can be set to 1 to indicate that retransmission of the HARQ PDU is required. The NACK bitmap is carried in a MAP-NACK frame.

Fig. 11 shows a block diagram of a method for controlling transmissions and retransmissions by a station-controlled multi-access point. In a first exemplary embodiment, a method comprises: a first indication message from a first network node indicating that the first network node is capable of communicating information with other network nodes in a set of network nodes and a second indication message from a second network node indicating that the second network node is capable of communicating information with other network nodes in the set of network nodes are received by a station (block 1102). For example, as shown in fig. 3A-3B, the first and second indication messages may include information identifying that the access point is capable of joint transmission. The first and second network nodes may include AP1 and AP2 included in the MAP-G, as shown in various embodiments of the present disclosure.

The method further comprises the following steps: a first request message is transmitted by a station to a first network node to associate the first network node with a network node group, and a second request message is transmitted to a second network node to associate the second network node with the network node group (block 1104). For example, as shown in step 403 of fig. 4, the first request message may include a MAP association request to AP1 and AP2 indicating a request to join the requested MAP-G.

In some embodiments, the method includes receiving, by the station, at least one of a first response message from the first network node and a second response message from the second network node indicating an acknowledgement that at least one of the first network node and/or the second network node is included in the group of network nodes.

In some embodiments, the method includes transmitting, by the station, a multi-network node group acknowledgement message that instructs the station to identify the network node group as including an acknowledgement of the first network node and the second network node.

In some embodiments, the first and second indication messages include multi-network node support information and hybrid automatic repeat request (HARQ) support information in an Extremely High Throughput (EHT) capability information element of the multi-network node capability indication message.

In some embodiments, the multi-network node support information comprises at least one of: information indicating that the second network node does not support multi-network node functionality, information indicating that the second network node supports selective multi-network node transmission, information indicating that the second network node supports joint multi-network node transmission, and information indicating that the second network node supports both selective multi-network node transmission and joint multi-network node transmission.

In some embodiments, the HARQ support information comprises at least one of: information indicating that the second network node does not support HARQ, information indicating that the second network node only supports Chase Combining (CC) HARQ, information indicating that the second network node only supports Incremental Redundancy (IR) HARQ, and information indicating that the second network node simultaneously supports CC HARQ and IR HARQ.

In some embodiments, the first request message includes a multi-network node group identifier that identifies the network node group.

In some embodiments, the first network node and the second network node are configured to align the timing of the first network node and the second network node with the timing associated with the station based on receiving the first request message.

In some embodiments, the method comprises: transmitting, by the station, a multi-network node re-association request message to update the group of network nodes, wherein updating the group of network nodes includes adding a new network node or removing a network node from the group of network nodes.

In some embodiments, the method comprises: upon receiving a multi-network node association response message from the first network node and the second network node, a timer is started by the station to track a lifecycle of the group of network nodes.

In some embodiments, the method comprises: the network node group is released by the station upon expiration of the timer.

In some embodiments, the method comprises: a disassociation message is transmitted by the station to all network nodes associated with the multi-network node group to release the network nodes from the multi-network nodes.

In some embodiments, the first network node and the second network node are interconnected via a switch through a Distribution System (DS) forming a multiple Basic Service Set (BSS).

In another exemplary embodiment, a method for wireless communication includes: transmitting, by a station, a first message to at least one of a first network node and a second network node in a group of network nodes, wherein the first message includes transmission configuration information. The method further comprises the following steps: receiving, by the station, data from at least one of the first network node and the second network node in the group of network nodes based on the transmission configuration information.

In some embodiments, the transmission configuration information comprises a request for the first network node to transmit data on the first channel.

In some embodiments, the data is transmitted by the first network node via a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU) that includes a plurality of aggregated media access control protocol data units (MPDUs).

In some embodiments, the transmission configuration information comprises a request for the first network node and the second network node to jointly transmit data to the station, and wherein the data is received from both the first network node and the second network node.

In some embodiments, the first network node transmits data on a first channel, and wherein the second network node transmits data on a second channel.

In some embodiments, the method includes merging, by a station, data transmitted by a first network node and a second network node in a Physical (PHY) baseband.

In some embodiments, the first network node transmits data on a first channel, and wherein the second network node transmits data on the first channel.

In some embodiments, the method includes combining, by the station, data transmitted by the first network node and the second network node in a Radio Frequency (RF) module.

In another exemplary embodiment, a method for wireless communication includes: scheduling information is received by a first network node included in the group of network nodes from a controller that controls transmissions by the group of network nodes to schedule a time at which to transmit a request-to-send message to the station. The method further comprises the following steps: transmitting, by a first network node included in the group of network nodes, a request to send message to the station at a time indicated by the controller based on the scheduling information.

In some embodiments, the request to send message is transmitted on a first channel, and wherein a second network node comprised in the group of network nodes is configured to transmit a second request to send message on a second channel.

In some embodiments, the request to send message is transmitted on a first channel, and wherein a second network node comprised in the group of network nodes is configured to transmit a second request to send message on the first channel.

In some embodiments, the method includes receiving, by a first network node included in the group of network nodes, a clear to send message from the station, the message indicating a request for the first network node to transmit data to the station.

In some embodiments, the sent message is allowed to be received by at least one other network node included in the group of network nodes.

In some embodiments, stations not included in the group of network nodes are configured to update a Network Allocation Vector (NAV) based on receiving the request to send message to prevent transmission of data during a transmit opportunity (TXOP) time period associated with the group of network nodes.

In some embodiments, the allowing to send the message comprises at least one of: a preferred multi-network node transmission type indicating one of a selective multi-network node transmission or a joint multi-network node transmission, a multi-network node transmission handover reservation for a joint multi-network node transmission, a hybrid automatic repeat request (HARQ) retransmission type indicating Chase Combining (CC) or Incremental Redundancy (IR), an identification of at least one network node in a network node group, a Received Signal Strength (RSSI) measurement, and a preferred downlink transmission power on an operating channel.

In another exemplary embodiment, a method for wireless communication includes: the method includes receiving, by a station, a first message from a first network node included in a group of network nodes, wherein the station initiates formation of the group of network nodes. The method further comprises the following steps: determining, by the station, that an error exists in a portion of the first message. The method also includes transmitting, by the station, a second message indicating a request for the first network node to retransmit a portion of the first message.

In some embodiments, the second message includes a Media Access Control (MAC) header for the multi-network node control frame.

In some embodiments, the MAC header comprises a common information field, wherein the common information field comprises at least one of: an identifier identifying a network node group, a Negative Acknowledgement (NACK) identifier indicating an error in the first message, a multi-network node type indicating a subsequent message to be transmitted in one of the joint multi-network node transmission or the selective multi-network node transmission, a multi-network node handover reservation indicating other network nodes in the network node group to reserve Resource Units (RUs) and to perform data cache synchronization with other network nodes in the group, and a HARQ type to be used for a subsequent HARQ retransmission.

In some embodiments, the method includes receiving, by the station, a third message including a portion of the first message that includes the error.

In some embodiments, the second message comprises a hybrid automatic repeat request (HARQ).

In some embodiments, the network node group controller is configured to schedule joint transmission of information included in the first message, the joint transmission of the information being performed by each network node included in the network node group.

In some embodiments, the first message comprises a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU) comprising a plurality of aggregated media access control protocol data units (MPDUs).

In some embodiments, the determining includes checking whether there is an error in each MPDU received in the first message.

In some embodiments, the second message includes a HARQ request for retransmission of at least one MPDU included in the first message.

In some embodiments, the second message includes a HARQ request for retransmission of a PPDU on a second Resource Unit (RU) included in a control frame of the third message.

In some embodiments, the method comprises: setting, by the station, a source address of the second message to an address of the station, a receive address of the second message to an address of a first network node included in the group of network nodes, and/or a destination address of the second message to an identifier associated with the group of network nodes, wherein the identifier associated with the group of network nodes is included in a common information portion of a Media Access Control (MAC) header of the second message.

In some embodiments, a second network node included in the group of network nodes is configured to receive a second message from the station and transmit a fourth message concurrently with transmitting a third message to the first network node, wherein the fourth message and the third message include the same MPDUs identified in the second message.

In some embodiments, the third message may be independently decodable by the station for the station to determine whether there is an error in the third message.

In some embodiments, the method comprises: determining, by the station, that the third message does not include any errors; and transmitting, by the station to the first network node, a fifth message acknowledging successful transmission of the third message.

In some embodiments, the network node group controller is a multi-basic service set (MBSS) controller configured to schedule subsequent multi-network node transmissions by network nodes included in the network node group during a TXOP time period associated with the network node group based on determining that the TXOP time period allows the network nodes to make the subsequent multi-network node transmissions.

In some embodiments, the MPDU identified in the second message is jointly transmitted by the first and second network nodes in the third message, and the first and second network nodes in the group of network nodes in the fourth message, over a Resource Unit (RU) specified in the second message.

In some embodiments, the method comprises: combining, by the station, the third message received in the joint transmission by the first network node and the second network node through one of a Radio Frequency (RF) module or a Physical (PHY) layer baseband; and transmitting, by the station, a fourth message to the first network node and the second network node to identify any failed MPDUs transmitted in the first message and the third message.

In some embodiments, the second message includes a Media Access Control (MAC) header for the multi-network node control frame.

In another exemplary embodiment, a method for wireless communication includes: a first message is received by a station from a first network node included in a group of network nodes. The method further comprises the following steps: determining, by the station, that a portion of the first message includes an error. The method further comprises the following steps: transmitting, by the station, a second message to a second network node included in the group of network nodes, wherein the second message includes a request to retransmit the portion of the first message that includes the error.

In some embodiments, the method comprises: a third message is received by the station from the second network node, wherein the third message includes a portion of the first message that includes the error.

In some embodiments, the second message comprises an identifier identifying a group of network nodes, and wherein the second network node is configured to transmit the third message based on determining that the identifier matches the group of network nodes associated with the second network node.

In some embodiments, the first message comprises a Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU) comprising a plurality of aggregated media access control protocol data units (MPDUs).

In some embodiments, the second message includes a hybrid automatic repeat request (HARQ) for retransmitting at least one MPDU identified in the first message.

In some embodiments, the second message comprises a bitmap corresponding to each MPDU transmitted in the first message, wherein the station is configured to update the bitmap based on identifying an error in the MPDU for the second network node to identify the MPDU having the error.

FIG. 12 is a block diagram representation of a portion of a hardware platform. A hardware platform 1205, such as a network device or a base station or wireless device, may include processor electronics 1210, such as a microprocessor, that implements one or more of the techniques presented herein. The hardware platform 1205 may include transceiver electronics 1215 for sending and/or receiving wired or wireless signals through one or more communication interfaces, such as an antenna 1220 or a wired interface. Hardware platform 1205 may implement other communication interfaces having defined protocols for transmitting and receiving data. Hardware platform 1205 may include one or more memories (not explicitly shown) configured to store information such as data and/or instructions. In some implementations, the processor electronics 1210 may include at least a portion of the transceiver electronics 1215. In some embodiments, at least some of the disclosed techniques, modules, or functions are implemented using a hardware platform 1205.

From the foregoing it will be appreciated that specific embodiments of the disclosed technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Accordingly, the disclosed technology is not limited, except as by the appended claims.

The disclosed embodiments and other embodiments, modules, and functional operations described herein may be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this application and their equivalents, or in combinations of one or more of them. The disclosed embodiments and other embodiments may be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more of them. The term "data processing apparatus" includes all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

A computer program (also known as a program, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this application can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include a mass storage device (e.g., a magnetic, magneto-optical disk, or optical disk) operatively coupled to receive data from or transfer data to the mass storage device, or both, for storing data. However, a computer need not have such a device. Computer-readable media suitable for storing computer program instructions and data include various forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD ROM disks and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

While this patent application contains many specifics, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features of the application, which are described in the context of separate embodiments, may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a described combination can in some cases be excised from the combination, and the combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the embodiments described in this patent application should not be understood as requiring such separation in all embodiments.

Only a few embodiments and examples are described and other embodiments, enhancements and variations can be made based on what is described and illustrated in this patent application.