Abstract:
Embodiments of the present invention provide a node grouping method, a node, and an access point (AP). The method comprises: receiving a grouping request sent by an AP; according to the grouping request, obtaining a received signal strength indicator (RSSI); obtaining a group Identity (ID) of a group determined according to the RSSI. In the embodiment of the present invention, nodes are grouped according to the RSSI, so as to solve the problems of contention collision and low network performance in a large-scale network, avoid the problem of unfair throughput incurred by the near-far effect, and reduce the phenomena of hidden terminals.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Patent Application No. PCT/CN2013/070746, filed on Jan. 21, 2013, which claims priority to Chinese Patent Application No. 201210017911.6, filed on Jan. 19, 2012, both of which are hereby incorporated by reference in their entireties. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to the technical field of communication, and in particular to a node grouping method, a node and an access point. 
       BACKGROUND 
       [0003]    With the development of communication technology, new requirements are proposed for the wireless network technology, i.e., a new generation of Wireless Fidelity (abbreviated as Wi-Fi) network of high rate, large scale and high throughput is required. The existing standard series of the Institute of Electrical and Electronics Engineers (abbreviated as IEEE) provide three channel access functions, including a Distributed Coordination Function (abbreviated as DCF), a Point Coordination Function (abbreviated as PCF) and a Hybrid Coordination Function (abbreviated as HCF). The DCF of Carrier Sense Multiple Access with Collision Avoidance (abbreviated as CSMA/CA), which is simple and convenient to be implemented, is a basic access mechanism and is used widely. As an optional access mechanism, PCF is based on DCF and performs centralized management on data transmission via a Point Coordinator (abbreviated as PC). HCF is a combination of DCF and PCF, and is used by a node which has Quality of Service (abbreviated as QoS) requirement. Therefore, the existing 802.11 IEEE standard series are based on contention. However, in a large scale network environment, the number of nodes which contend the channels at the same time is increased rapidly, thereby resulting in severe contention failure and thus lowering the network efficiency. In addition, the problem of hidden terminals in the wireless network may be more severe in the large scale network. It is indicated by a research that, in a network with infrastructure, the probability that any two nodes within the coverage area of a central node are hidden terminals is 41%. The problem of hidden terminals may become more severe with the increase of the network scale. If a delivery rate is 99% in a network without hidden terminal, the delivery rate is reduced to 94% in a network with hidden terminals of 5%. Therefore, the problem of hidden terminals is to be solved or alleviated urgently in a large scale network. 
         [0004]    In view of this, the conventional technology can not satisfy people&#39;s new requirement on the wireless network, especially for the large scale network. Therefore, an appropriate solution is required to solve the problems brought by the large scale network. 
       SUMMARY 
       [0005]    A method for grouping a node is provided according to embodiments of the disclosure, to solve problems such as contention conflict and low network efficiency in a large scale network, and reduce probability of hidden terminals. 
         [0006]    In one aspect, a method for grouping a node is provided, including: receiving a grouping request sent from an Access point (AP); acquiring a Received Signal Strength Indicator (RSSI) based on the grouping request; and acquiring an Identity (ID) of a group that the node belongs to determined based on the RSSI. 
         [0007]    In another aspect, a method for grouping a node is provided, including: sending to a node a grouping request, so that the node acquires a Received Signal Strength Indicator (RSSI) based on the grouping request; and acquiring an Identity (ID) of a group that the node belongs to determined based on the RSSI. 
         [0008]    In another aspect, a method for grouping a node is provided, including: receiving a group joining request sent from a first node; sending a first grouping poll to each node in a first set of nodes based on the group joining request, where the first set of nodes is composed of a grouped node in nodes served by an Access point (AP); receiving a first grouping acknowledgement sent from each node in a second set of nodes, where the second set of nodes is composed of a node that monitors the group joining request in the first set of nodes; receiving a two-way neighbor node list sent from the first node, where the two-way neighbor node list includes a third set of nodes which is composed of a node corresponding to the first grouping acknowledgement monitored by the first node; and grouping the first node based on the two-way neighbor node list. 
         [0009]    In another aspect, a method for grouping a node is provided, including: sending to an Access point (AP) a group joining request, so that the AP sends a first grouping poll to each node in a first set of nodes based on the group joining request and receives a first grouping acknowledgement sent from each node in a second set of nodes, where the first set of group is composed of a grouped node in nodes served by the AP, and the second set of nodes is composed of a node that monitors the group joining request in the first set of nodes; monitoring the first grouping acknowledgement sent from each node in the second set of nodes to the AP; and sending a two-way neighbor node list to the AP, where the two-way neighbor node list includes a third set of nodes which is composed of a node corresponding to the first grouping acknowledgement that is monitored. 
         [0010]    In another aspect, a node is provided, including: a first receiving module, configured to receive a grouping request sent from an Access point (AP); a first acquisition module, configured to acquire a Received Signal Strength Indicator (RSSI) based on the grouping request received by the first receiving module; and a second acquisition module, configured to acquire an Identity (ID) of a group that the node belongs to determined based on the RSSI acquired by the first acquisition module. 
         [0011]    In another aspect, an access point is provided, including: a first sending module, configured to send to a node a grouping request, so that the node acquires a Received Signal Strength Indicator (RSSI) based on the grouping request; and a first acquisition module, configured to acquire an Identity (ID) of a group that the node belongs to determined based on the RSSI. 
         [0012]    In another aspect, an access point is provided, including: a first receiving module, configured to receive a group joining request sent from a first node; a first sending module, configured to send a first grouping poll to each node in a first set of nodes based on the group joining request received by the first receiving module, where the first set of nodes is composed of a grouped node in nodes served by the Access point (AP); a second receiving module, configured to receive the first grouping acknowledgement sent from the second set of nodes, where the second set of node is composed of a node that monitors the group joining request sent from the first sending module in the first set of nodes; a third receiving module, configured to receive a two-way neighbor node list sent from the first node, where the two-way neighbor node list includes a third set of nodes, and the third set of nodes is composed of a node corresponding to the first grouping acknowledgement monitored by the first node; and a first grouping module, configured to group the first node based on the two-way neighbor node list received by the third receiving module. 
         [0013]    In another aspect, a node is provided, including: a first sending module, configured to send to an Access point (AP) a group joining request, so that the AP sends a first grouping poll to each node in a first set of nodes based on the group joining request and receives a first grouping acknowledgement sent from each node in a second set of nodes, where the first set of nodes is composed of a grouped node in nodes served by the AP, and the second set of nodes is composed of a node that monitors the group joining request in the first set of nodes; a first monitoring module, configured to monitor the first grouping acknowledgement sent from each node in the second set of nodes to the AP; and a second sending module, configured to send a two-way neighbor node list to the AP, where the two-way neighbor node list includes a third set of nodes which is composed of a node corresponding to the first grouping acknowledgement monitored by the first monitoring module. 
         [0014]    Based on the foregoing technical solutions, in the node grouping method, node and access point according to the embodiments of the disclosure, by grouping the node based on RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    In order to clearly illustrate the technical solutions of embodiments provided by the disclosure, drawings to be used in the disclosure of the embodiments or the prior art will be briefly described in the following. Obviously, the drawings described in the following are only some of embodiments of the disclosure, and those skilled in the art may obtain other drawings based on these drawings without any creative work. 
           [0016]      FIG. 1  is a schematic flow chart of a method for grouping a node provided according to an embodiment of the disclosure. 
           [0017]      FIG. 2  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0018]      FIG. 3  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0019]      FIG. 4A  and  FIG. 4B  are format charts of a MAC frame provided according to an embodiment of the disclosure. 
           [0020]      FIG. 5  is a format chart of a beacon frame provided according to an embodiment of the disclosure. 
           [0021]      FIG. 6  is a schematic flow chart of data transmission provided according to an embodiment of the disclosure. 
           [0022]      FIG. 7  is a schematic flow chart of a CP period provided according to an embodiment of the disclosure. 
           [0023]      FIG. 8  is a schematic flow chart of data transmission provided according to another embodiment of the disclosure. 
           [0024]      FIG. 9  is a schematic flow chart of data transmission provided according to another embodiment of the disclosure. 
           [0025]      FIG. 10  is a format chart of a TIM frame provided according to another embodiment of the disclosure. 
           [0026]      FIG. 11  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0027]      FIG. 12  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0028]      FIG. 13  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0029]      FIG. 14  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0030]      FIG. 15  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0031]      FIG. 16A  and  FIG. 16B  are format charts of a control frame provided according to an embodiment of the disclosure. 
           [0032]      FIG. 17  is a format chart of a data frame provided according to an embodiment of the disclosure. 
           [0033]      FIG. 18  is a schematic flow chart of a method for grouping a node provided according to another embodiment of the disclosure. 
           [0034]      FIG. 19  is a schematic block diagram of a node provided according to an embodiment of the disclosure. 
           [0035]      FIG. 20  is a schematic block diagram of a node provided according to another embodiment of the disclosure. 
           [0036]      FIG. 21  is a schematic block diagram of a node provided according to another embodiment of the disclosure. 
           [0037]      FIG. 22  is a schematic block diagram of an AP provided according to an embodiment of the disclosure. 
           [0038]      FIG. 23  is a schematic block diagram of an AP provided according to another embodiment of the disclosure. 
           [0039]      FIG. 24  is a schematic block diagram of an AP provided according to another embodiment of the disclosure. 
           [0040]      FIG. 25  is a schematic block diagram of an AP provided according to another embodiment of the disclosure. 
           [0041]      FIG. 26  is a schematic block diagram of an AP provided according to another embodiment of the disclosure. 
           [0042]      FIG. 27  is a schematic block diagram of an AP provided according to another embodiment of the disclosure. 
           [0043]      FIG. 28  is a schematic block diagram of a node provided according to another embodiment of the disclosure. 
           [0044]      FIG. 29  is a schematic block diagram of a node provided according to another embodiment of the disclosure. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0045]    The technical solutions according to the embodiments of the disclosure will be described clearly and completely in conjunction with the drawings of the embodiment of the disclosure. Obviously, the disclosed embodiments are only some but not all of embodiments of the disclosure. Other embodiments obtained by those skilled in the art without any creative work based on the embodiments of the disclosure fall within the protection scope of the disclosure. 
         [0046]    It should be understood that, the technical solutions in the embodiments of the disclosure are applicable to various of communication systems, such as a Global System for Mobile Communications (abbreviated as GSM) system, a Code Division Multiple Access (abbreviated as CDMA) system, a Wideband Code Division Multiple Access (abbreviated as WCDMA) system, a General Packet Radio Service (abbreviated as GPRS), a Long Term Evolution (abbreviated as LTE) system, a LTE Frequency Division Duplex (abbreviated as FDD) system, a LTE Time Division Duplex (abbreviated as TDD) system and a Universal Mobile Telecommunications System (abbreviated as UMTS). 
         [0047]      FIG. 1  is a schematic flow chart of a method  100  for grouping a node provided according to an embodiment of the disclosure. The method  100  may be implemented by a node (a station STA). As shown in  FIG. 1 , the method includes steps  110 ,  120  and  130  as follows. 
         [0048]    S 110  may include receiving a grouping request sent from an Access Point (abbreviated as AP). 
         [0049]    S 120  may include acquiring a Received Signal Strength Indicator (abbreviated as RSSI) based on the grouping request. 
         [0050]    S 130  may include acquiring an Identity (abbreviated as ID) of a group that the node belongs to determined based on the RSSI. 
         [0051]    After receiving the grouping request sent from the AP, the node may acquire the RSSI based on the grouping request and thus acquire the ID of the group that the node belongs to. 
         [0052]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, by grouping the node based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0053]    In addition, in an embodiment of the disclosure, by grouping the node based on the RSSI, the power may be controlled based on the actual situation, an uplink-downlink scheduling transmission reference may be provided for a power-saving protocol, and collision degree may be reduced by combining a directional antenna with a Multi-User Multiple Input Multiple Output (abbreviated as MU-MIIMO) technology and system capacity may be increased. 
         [0054]    An AP itself is a node in a WiFi network, and the AP may be regarded as a special station STA or may be a central node for managing and controlling in the network. In an embodiment of the disclosure, the node may be an AP or other nodes, which may be determined based on the actual situation, and the embodiment of the disclosure is not limited thereto. 
         [0055]    In an embodiment of the disclosure, as shown in  FIG. 2 , before acquiring the ID of the group that the node belongs to determined based on the RSSI in S 130 , the method  100  may further include a step  140  as follows. 
         [0056]    S 140  may include sending the RSSI to the AP. 
         [0057]    Correspondingly, the acquiring the ID of the group that the node belongs to determined based on the RSSI in S 130  may include steps  134  and  135  as follows. 
         [0058]    S 134  may include receiving a message including the ID of the group sent from the AP, where the ID of the group is determined by the AP based on the RSSI and a preset RSSI grouping range. 
         [0059]    S 135  may include acquiring the ID of the group from the message including the ID of the group. 
         [0060]    That is, after acquiring the RSSI based on the grouping request sent from the AP, the node may sent to the AP the RSSI; and after receiving the RSSI sent from the node, the AP may determine the ID of the group that the node belongs to based on the RSSI and a preset RSSI grouping range. For example, if the RSSI belongs to the RSSI grouping range of a certain group, the group is determined as the one that the node belongs to. After determining the ID of the group that the node belongs to, the AP may send to the node a message including the ID of the group, and then the node may acquire the ID of the group that the node belongs to based on the message including the ID of the group. 
         [0061]    In an embodiment of the disclosure, the preset RSSI grouping range is a RSSI range which can be grouped into each group. For example, the RSSI of a certain node is 2, and the preset RSSI grouping range is defined as follows: 1≦ the RSSI range of a first group &lt;3, 3≦ the RSSI range of a second group &lt;5, and 5≦ the RSSI range of a third group &lt;7; the node may be grouped into the first group since the RSSI of the node is 2, which is in the RSSI range of the first group. 
         [0062]    It may be understood that, the foregoing preset range of each group is only an example, which is not limited to the disclosure, and the specific preset range of each group may be determined according to actual situation. In an embodiment of the disclosure, as shown in  FIG. 3 , the acquiring an ID of a group that the node belongs to determined based on the RSSI in S 130  includes a step  136  as follows. 
         [0063]    S 136  may include determining the ID of the group that the node belongs to based on the RSSI and the preset RSSI grouping range. 
         [0064]    For example, in a case that the RSSI belongs to the RSSI range of a certain group, the group may be determined as a group that the node belongs to. 
         [0065]    The method may further include a step  160  as follows. 
         [0066]    S 160  may include sending to the AP a message including the ID of the group. 
         [0067]    For example, the node may send to the AP the message including the ID of the group that the node belongs to within a period of time determined based on the ID of the group that the node belongs to, a Distributed Coordination Function Inter-frame Space (abbreviated as DIFS) and a minimum value of Contention Window (abbreviated as CW) CWmin. For example, the time when the AP sends the ID of the group that the node belongs to may be determined based on the following formula (1). 
         [0000]        T= ID*DIFS+random(0,CWmin)  (1)
 
         [0000]    where T is the determined sending time. 
         [0068]    It should be understood that, the foregoing formula (1) is only an example, which is not limited to the embodiment of the disclosure, and the reporting time of the node may be determined based on other formulas. For example, supposing that the IDs of the groups are respectively 1, 2, 3, 4, 5, the node may determine the reporting time based on the following formula (2). 
         [0000]        T (ID−4)*DIFS+random(0,CWmin)  (2)
 
         [0069]    Alternatively, after the ID of the group that the node belongs to is determined, the node may send the ID of the group to the AP by carrying the ID of the group in the uplink data reported for the first time within a period of time specified by the AP in a Contention Period (abbreviated as CP). 
         [0070]    Therefore, in the embodiment of the disclosure, signaling conflict may be reduced by decentralizing the time when the node reports the ID of the group that the node belongs to. 
         [0071]    In an embodiment of the disclosure, the ID of the group may be sent to the AP via a MAC frame. For example, a domain for indicating the ID of the group that the node belongs to may be added into a frame head of a Medium Access Control (abbreviated as MAC) frame, and the domain may be referred to as a GID domain for convenience in an embodiment of the disclosure. For example, as shown in  FIG. 4A , a GID domain of 3 bytes is added into the frame head of a MAC data frame. In sending information from the node to the AP, since the AP is unique, 6 bytes in a Receiver address (abbreviated as RA) for indicating a target address is unused, so certain bytes, such as the 3 bytes shown in  FIG. 4B , may be selected from the RA field in the frame head of the MAC control frame to indicate the ID of the group that the node belongs to. It should be understood that, the 3 bytes shown in  FIGS. 4A and 4B  is only an example, and the GID domain may occupy bytes of other values, which may be determined according to actual situation. The MAC data frame shown in  FIG. 4A  further includes: a Frame Control, a Duration, an Address 1  (abbreviated as A 1 ), an Address 2  (abbreviated as A 2 ), an Address 3  (abbreviated as A 3 ), a Sequence (abbreviated as seq), an Address 4  (abbreviated as A 4 ), a Quality of Service (abbreviated as QoS), a High Through (abbreviated as HT), a body and a Frame Check Sequence (abbreviated as FCS). The MAC control frame in  FIG. 4B  further includes: a Frame Control, a Duration, a RA, a Transmit (abbreviated as TA) and a FCS. The specific meanings of these fields may refer to the conventional technology, and the description thereof is omitted herein for concision. 
         [0072]    In an embodiment of the disclosure, the preset RSSI grouping range may be determined by negotiation between the node and the AP in advance. For example, the RSSI grouping range may be determined by negotiation when the node and the AP are associated. Alternatively, the preset RSSI grouping range may be informed to the node by the AP before the AP sends to the node a grouping request. Alternatively, the preset RSSI grouping range may be carried in a grouping request sent from the AP to the node, where the grouping request may be indicated by a beacon frame. For example, as shown in  FIG. 5 , the preset RSSI grouping range may be added into the body of the beacon frame. The beacon frame in  FIG. 5  further includes: a Frame Control, a Duration, a A 1 , a A 2 , a A 3 , a Sequence, a A 4 , a body and a FCS. The specific meanings of these fields may refer to the conventional technology, and the description thereof is omitted herein for concision. 
         [0073]    Therefore, the receiving a grouping request sent from an AP in S 110  may include: 
         [0074]    receiving the grouping request indicated by the beacon frame and sent from the AP, where the body of the beacon frame carries the preset RSSI grouping range. 
         [0075]    In an embodiment of the disclosure, the preset RSSI grouping range may be set based on requirement or may be set automatically by the AP. For example, the preset RSSI grouping range may be determined based on, for example, tolerance of contention in the group, the number of nodes in the group and the RSSI value level of the group. 
         [0076]    In an embodiment of the disclosure, the ID of the group that the node belongs to may be determined based on the RSSI and the preset RSSI grouping range in conjunction with other factors, such as location and energy information of the node. In an embodiment of the disclosure, the ID of the group that the node belongs to may be determined based on the RSSI and the preset RSSI grouping range, or the ID of the group that the node belongs to may be determined based on the RSSI of the node and the RSSIs of other groups. For example, the RSSIs of all the nodes may be acquired, and the nodes are averagely distributed to each group based on the RSSIs of all the nodes. Therefore, all solutions, as long as in which the ID of the group that the node belongs to is determined based on the RSSI, are within the protection scope of the disclosure. 
         [0077]    The process of grouping provided according to the embodiment of the disclosure is described above, and the normal operation stage of the network after the nodes are grouped will be described in detail below. 
         [0078]    In an embodiment of the disclosure, as shown in  FIG. 6 , the method  100  may further include steps  172 ,  174  and  176  as follows. 
         [0079]    S 172  may include receiving, from the AP, a message of an access time period which only includes a CP, where the CP includes the access time divided for each group. 
         [0080]    S 174  may include determining the access time of the group that the node belongs to based on the access time period. 
         [0081]    S 176  may include transmitting data with the AP within the access time of the group that the node belongs to. 
         [0082]    That is, the AP may determine the access time period after the grouping is finished. The access time period only includes the CP, and the CP includes the access time divided for each group. For example, the AP may determine the access time of each group based on the number of the nodes in each group, or the traffic of nodes in each group, or the number of nodes and the traffic of nodes in each group. After determining the access time period, the AP may send the access time period to the grouped nodes via a broadcast frame. After receiving the message including the access time period sent from the AP, the node may determine the access time of the group that the node belongs to based on the access time period, and thus the node may transmit data with the AP within the access time of the group that the node belongs to. 
         [0083]    The access time period includes not only the CP and but also a Contention-Free Period (abbreviated as CFP), where the CFP is not used well. Therefore, in this embodiment, the access time period only includes a CP, thereby avoiding the CFP in the conventional technology, taking full use of time, and reducing the time cost. 
         [0084]    In an embodiment of the disclosure, the CP may only include the access time divided for each group, or the CP may include not only the access time divided for each group but also an access time which is not divided for any group. The access time which is not divided for any group may be used for transmitting delay-sensitive service. For example, as shown in  FIG. 7 , CP 1  includes not only the access time divided for group 1, group 2, group 3, group 4 . . . , but also the time T for transmitting delay-sensitive service. 
         [0085]    Therefore, in an embodiment of the disclosure, as shown in  FIG. 8 , the method may further include steps  182  and  184  as follows. 
         [0086]    S 182  may include determining that the data is delay-sensitive service and transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period. 
         [0087]    S 184  may include transmitting the data with the AP within the access time which is not divided for any group in the first access time period. 
         [0088]    That is, in a case that the node determines that the transmitted data is delay-sensitive service and the transmission of the data is not completed within the access time of the group that the node belongs to in the first access time period, the node may transmit the data with the AP within the access time which is not divided for any group in the first access time period. 
         [0089]    Therefore, in an embodiment of the disclosure, the average end-to-end transmission delay of the delay-sensitive service may be reduced effectively by setting a time for transmitting the delay-sensitive service in the CP. 
         [0090]    In an embodiment of the disclosure, as shown in  FIG. 9 , before transmitting the data with the AP within the access time of the group that the node belongs to, the method  100  may further include steps  192  and  194  as follows. 
         [0091]    S 192  may include receiving a Traffic Indication Map (abbreviated as TIM) frame sent from the AP, where the TIM frame carries information of the node which has cache downlink data at the AP in each group. 
         [0092]    S 194  may include determining that there is downlink cache data at the AP based on the TIM frame. 
         [0093]    That is, the AP sends a TIM frame to the node based on the stored cache data about the grouped nodes. The TIM frame carries information of the node which has cache downlink data at the AP in each group. After receiving the TIM frame, the node acquires corresponding data from the AP if the node determines that it has cache downlink data at the AP based on the TIM. 
         [0094]    For example, as shown in  FIG. 10 , a GID domain may be added into the TIM frame. The GID domain in  FIG. 10  has 7 bits, which may indicate  128  groups at most. The TIM frame in  FIG. 10  further includes: a Category, an Action, a Check beacon, a Timestamp and a TIM element. The meaning of these fields may refer to the conventional technology, and detailed description thereof is omitted herein for concision. 
         [0095]    Thus it can be seen that, the insufficient of partial virtual bitmap of the TIM frame can be solved by adding the domain for indicating the ID of the group that the node belongs to into the TIM frame. 
         [0096]    Therefore, in the embodiment of the disclosure, by grouping the node based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0097]    The method for grouping the node provided according to the embodiment of the disclosure is described from a perspective of node, and the method for grouping the node provided according to the embodiment of the disclosure may be described in the following from a perspective of AP. 
         [0098]      FIG. 11  is a method for grouping a node provided according to an embodiment of the disclosure. The method may be implemented by an AP. As shown in  FIG. 11 , the method  200  includes steps  210  and  220  as follows. 
         [0099]    S 210  may include sending to a node a grouping request, so that the node acquires a RSSI based on the grouping request. 
         [0100]    S 220  may include acquiring an ID of a group that the node belongs to determined based on the RSSI. 
         [0101]    Therefore, in an embodiment of the disclosure, by grouping the node based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0102]    In addition, in an embodiment of the disclosure, by grouping the node based on the RSSI, the power may be controlled based on the actual situation, an uplink-downlink scheduling transmission reference may be provided for a power-saving protocol, and collision degree may be reduced by combining a directional antenna with an MU-MIIMO technology and system capacity may be increased. 
         [0103]    In an embodiment of the disclosure, as shown in  FIG. 12 , the acquiring the ID of the group that the node belongs to determined based on the RSSI in S 220  may further include steps  224  and  228  as follows. 
         [0104]    S 224  may include receiving a message including the ID of the group sent from the node, where the ID of the group is determined by the node based on the RSSI and a preset RSSI grouping range. 
         [0105]    S 228  may include acquiring the ID of the group from the message including the ID of the group. 
         [0106]    In an embodiment of the disclosure, as shown in  FIG. 13 , before acquiring the ID of the group that the node belongs to determined based on the RSSI in S 220 , the method  200  may further include a step  240  as follows. 
         [0107]    S 240  may include receiving the RSSI sent from the node. 
         [0108]    Correspondingly, the acquiring the ID of the group that the node belongs to determined based on the RSSI in S 220  includes a step  226  as follows. 
         [0109]    S 226  may include determining the ID of the group that the node belongs to based on the RSSI and the preset RSSI grouping range. For example, if the RSSI belongs to the RSSI grouping range of a certain group, the group is determined as the one that the node belongs to. 
         [0110]    Correspondingly, the method further includes a step  250  as follows. 
         [0111]    S 250  may include sending to the node a message including the ID of the group. 
         [0112]    In an embodiment of the disclosure, the preset RSSI grouping range may be determined by negotiation in advance or may be carried along with the sent grouping request. For example, the preset RSSI grouping range is carried in a beacon frame which indicates the grouping request. 
         [0113]    Therefore, the sending the grouping request to an AP in S 210  may include: 
         [0114]    sending to the AP the grouping request indicated by a beacon frame, where the beacon frame carries the preset RSSI grouping range. 
         [0115]    The process of grouping provided according to the embodiment of the disclosure is described above, and the normal operation stage of the network after the nodes are grouped may be described in detail below. 
         [0116]    In an embodiment of the disclosure, the AP may send to the node an access time period which only includes a CP, where the CP includes the access time divided for each group, so that the node may transmit data with the AP within the access time of the group that the node belongs to. 
         [0117]    Therefore, the access time period only includes the CP, thereby avoiding the CFP in the conventional technology, taking full use of time, and reducing the time cost. 
         [0118]    In an embodiment of the disclosure, in a case that there is an idle of the sum of the DIFS and CWmin time, the AP may issue a grouping CP releasing message and re-send to the node the reset access time period, such as the CP 2  shown in  FIG. 7 . 
         [0119]    Therefore, the grouping access time is reset in a case that there is an idle in the group, thereby taking full use of time and reducing the time cost. 
         [0120]    In an embodiment of the disclosure, the CP may further include an access time which is not divided for any group, so that in a case that the node determines that the data is delay-sensitive service and transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period, the node may transmit the data with the AP within the access time which is not divided for any group in the first access time period, such as the time T in CP 1  shown in  FIG. 7 . Therefore, in the embodiment of the disclosure, the average end-to-end transmission delay of the delay-sensitive service may be reduced effectively by setting a time for transmitting the delay-sensitive service in the CP. 
         [0121]    In an embodiment of the disclosure, the AP may send to the node a TIM frame after determining that the grouping is completed, where the TIM frame carries information of the node which has cache downlink data at the AP in each group. For example, as shown in  FIG. 10 , a GID domain of 7 bits is added into the TIM frame. 
         [0122]    Therefore, in the embodiment of the disclosure, a large number of nodes in the large scale network may be supported by setting a domain of an ID of a carrying group in the TIM frame for indicating, in conjunction with the virtual bitmap, which node in which group has cache data at the AP. 
         [0123]    Therefore, in the embodiment of the disclosure, by grouping the node based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0124]    Another method for grouping a node is further provided according to an embodiment of the disclosure. The method may be described in detail below in conjunction with  FIG. 14  to  FIG. 18 . 
         [0125]      FIG. 14  is a schematic flow chart of a method  300  for grouping a node provided according to an embodiment of the disclosure. The method may be implemented by an AP. As shown in  FIG. 14 , the method  300  includes steps  310 ,  320 ,  330 ,  340  and  350  as follows. 
         [0126]    S 310  may include receiving a group joining request sent from a first node. 
         [0127]    S 320  may include sending a first grouping poll to each node in a first set of nodes based on the group joining request, where the first set of nodes is composed of grouped nodes in nodes served by the AP. 
         [0128]    S 330  may include receiving a first grouping acknowledgement sent from each node in a second set of nodes, where the second set of nodes is composed of the node that monitors the group joining request in the first set of nodes. 
         [0129]    S 340  may include receiving a two-way neighbor node list sent from the first node, where the two-way neighbor node list includes a third set of nodes, and the third set of node is composed of the node corresponding to the first grouping acknowledgement monitored by the first node. 
         [0130]    S 350  may include grouping the first node based on the two-way neighbor node list. 
         [0131]    The AP may send the first grouping poll to each node in the first set of nodes after receiving the group joining request sent from the first node, where the first set of nodes is composed of grouped nodes in nodes served by the AP. The second set of nodes, which is composed of the node that monitors the group joining request in the second set of nodes, sends to the AP the first grouping acknowledgement. The first node monitors the first grouping acknowledgement sent from the node in the second set of nodes and sends to the AP the two-way neighbor node list, where the two-way neighbor node list includes a third set of nodes which is composed of the node corresponding to the first grouping acknowledgement monitored by the first node. The AP groups the first node based on the two-way neighbor node list after receiving the two-way neighbor node list sent from the first node. 
         [0132]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the nodes based on the two-way neighbor node lists of the nodes, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0133]    Furthermore, in an embodiment of the disclosure, the neighbor node information may be collected by monitoring the grouping acknowledgement sent from the polled node to the AP, thereby reducing the probability of hidden terminals. 
         [0134]    In an embodiment of the disclosure, the AP may check the existing grouping after receiving the two-way neighbor node list sent from the first node, and then the first node may be grouped into such a group that all the nodes in this group are the two-way neighbor nodes of the first node; and the first node may be grouped into a group which includes the least number of nodes in a case that nodes in multiple groups all belong to the two-way neighbor node list of the first node; or the first node itself may be grouped into an independent group in a case that there is no such a group that all the nodes in this group are the two-way neighbor nodes of the first node. 
         [0135]    In an embodiment of the disclosure, the group joining request sent from the first node may be an association request in a case that the first node is associated with the AP, or may be a group joining request for joining into a group sent after the first node is associated with the AP. 
         [0136]    In an embodiment of the disclosure, as shown in  FIG. 15 , before the receiving the group joining request sent from the first node in S 110 , the method  300  may further include steps  362 ,  364  and  366  as follows. 
         [0137]    S 362  may include sending a second grouping poll to each node in the first set of nodes, so that the second node, which may be any node in the first set of nodes, may send a second grouping acknowledgement to the AP, and the node that monitors the second grouping poll and the second grouping acknowledgement in the first set of nodes records the second node into its one-way neighbor node list. 
         [0138]    S 364  may include receiving the one-way neighbor node list sent from each node in the first set of nodes. 
         [0139]    S 366  may include grouping the first set of nodes based on the one-way neighbor node list, where the nodes in each group are neighbor nodes with each other. 
         [0140]    That is, the AP sends the second grouping poll to each node in the first set of nodes. The second node, which may be any node in the first set of nodes, may send the second grouping acknowledgement to the AP after receiving the second grouping poll. The node that monitors the second grouping poll and the second grouping acknowledgement in the first set of nodes records the second node into its one-way neighbor node list. Each node in the first set of nodes sends the one-way neighbor list to the AP, and then the AP may group the first set of nodes after receiving the one-way neighbor node list sent from each node in the first set of nodes, where the nodes in each group are neighbor nodes with each other. 
         [0141]    Therefore, in the embodiment of the disclosure, the time cost of grouping may be reduced by grouping multiple nodes at a time and grouping a single node independently. 
         [0142]    In the embodiment of the disclosure, the nodes in each group are neighbor nodes with each other, i.e., each node is the two-way neighbor node of the other node, and there is no hidden terminal between any two nodes. 
         [0143]    In an embodiment of the disclosure, the AP may group all the nodes in the first set of nodes after receiving the one-way neighbor node list sent from each node in the first set of nodes, and the process of grouping may include: 
         [0144]    a) generating a directed graph based on the received one-way neighbor node lists of all the nodes, and drawing a directed relationship of these nodes in the graph; 
         [0145]    b) selecting a node which has the least number of the two-way neighbor nodes from all the nodes based on the directed graph and establishing a first group; 
         [0146]    c) selecting the node which has the least number of the two-way neighbor nodes from the rest of the nodes and checking the existing grouping; grouping the node into such a group that all nodes in the group are the two-way neighbor nodes of the node; and in a case that there have multiple groups that all nodes in these groups are the two-way neighbor nodes of the node, grouping the node into a group which has the least number of nodes in the multiple groups; and establishing a new group for the node in a case that there is no such a group that all nodes in the group are the two-way neighbor nodes of the node; and 
         [0147]    d) performing step c until all the nodes are grouped. 
         [0148]    It should be understood that the foregoing process of grouping is only an embodiment of the disclosure, the disclosure is not limited thereto, and the grouping may be implemented in other ways. 
         [0149]    It should be understood that, in an embodiment of the disclosure, the first set of nodes may be grouped in other ways. For example, a node in the first set of nodes may be grouped into a group first, and then S 310 , S 320 , S 330 , S 340  and S 350  in the method  300  may be performed in sequence, i.e., each node may be grouped respectively. For another example, the second node, which may be any node in the first set of nodes, may collect information of hidden nodes and report the information of hidden nodes to the AP, and then the AP may group the nodes which have no hidden relationship into a group after receiving the information of hidden nodes reported by all the nodes, that is, the nodes in a same group are neighbor nodes with each other. 
         [0150]    In an embodiment of the disclosure, the receiving the one-way neighbor node list sent from each node in the first set of nodes may include: 
         [0151]    receiving the one-way neighbor node list sent from each node in the first set of nodes in an order that the second grouping poll is received. 
         [0152]    That is, each node in the first set of nodes sends to the AP the one-way neighbor node list in an order of being polled, thereby avoiding signaling conflict caused by centralized reporting of the one-way neighbor node lists. 
         [0153]    In an embodiment of the disclosure, the sending the first grouping poll to each node in the first set of nodes in S 320  includes: 
         [0154]    sending, to each node in the first set of nodes, a first grouping poll indicated by a Type field, a Subtype field and a More Frag field included in a control frame. 
         [0155]    The receiving the first grouping acknowledgement sent from each node in the second set of nodes to the AP in S 330  includes: 
         [0156]    receiving the first grouping acknowledgement sent from each node in the second set of nodes to the AP and indicated by a Type field, a Subtype field and a More Frag field included in a control frame. 
         [0157]    The sending the second grouping poll to each node in the first set of nodes in S 362  includes: 
         [0158]    sending, to each node in the first set of nodes, a second grouping poll indicated by a Type field, a Subtype field and a More Frag field included in a control frame. 
         [0159]    The second grouping acknowledgement is indicated by a Type field, a Subtype field and a More Frag field included in a control frame. 
         [0160]    In an embodiment of the disclosure, the first and the second grouping polls may be indicated by the control frame; and the first and the second grouping acknowledgements may also be indicated by the control frame. For ease of description, the frame configured to indicate the first or the second grouping polls may be referred to as a grouping-poll frame, and the frame configured to indicate the first or the second grouping acknowledgements may be referred to as a grouping-ACK frame. It may be understood that the naming of the grouping-poll frame and the grouping-ACK frame is only for ease of description, and the disclosure is not limited thereto. 
         [0161]    In the conventional technology, the control frame generally includes: a Frame Control, a Duration, a RA, a TA and a FCS. The Frame Control includes a Protocol Version, a Type, a Subtype, a to Distributed System (abbreviated as to DS), a From Distributed System (abbreviated as From DS), a More Frag, a Retry, a Power Mangent (abbreviated as Pwr Mgt), a More Data, a Protected Frame and an Order, as shown in  FIG. 16A  and  FIG. 16B . A Request to Send (abbreviated as RTS) frame and a Clear to Send (abbreviated as CTS) frame are both very short frames, and usually may not adopt the frag mechanism, hence the “More Frag” field in the Frame Control domain may be given a double meaning, i.e., More Frag/Grouping. In a case that it is detected from the Type field of the Frame Control field that the frame is a RTS or CTS frame, the “More Frag/Grouping” indicates whether the frame is a RTS (CTS) frame or a grouping-poll (grouping-ACK) frame. 
         [0162]    For example, as shown in  FIG. 16A , the frame may be a RTS frame or a grouping-poll frame in a case that the Type field is 01 and the Subtype field is 1011. In this case, the frame is a grouping poll frame in a case that the More Frag/Grouping is 1, and the frame is a RTS frame in a case that the More Frag/Grouping is 0. 
         [0163]    In the same way, as shown in  FIG. 16B , the frame may be a CTS frame or a grouping-ACK frame in a case that the Type field is 01 and the Subtype field is 1100. In this case, the frame is a grouping-ACK frame in a case that the More Frag/Grouping is 1, and the frame is a CTS frame in a case that the More Frag/Grouping is 0. The contents and meanings of other fields in the frames shown in  FIG. 16A  and  FIG. 16B  may refer to the conventional technology, and detailed description thereof is omitted herein for concision. 
         [0164]    It may be understood that, the values of the foregoing fields are only examples, and the disclosure is not limited thereto. 
         [0165]    In an embodiment of the disclosure, the receiving a two-way neighbor node list sent from the first node in S 340  includes: 
         [0166]    receiving the two-way neighbor node list carried in a data frame and sent from the first node, where a Type field, a Subtype field and a More Data field in the data frame indicate that the data frame carries the two-way neighbor node list. 
         [0167]    The receiving the one-way neighbor node list sent from each node in the first set of nodes in S 364  includes: 
         [0168]    receiving the one-way neighbor node list carried in a data frame and sent from each node in the first set of nodes, where a Type field, a Subtype field and a More Data field in the data frame indicate that the data frame carries the one-way neighbor node list. 
         [0169]    In the conventional technology, the data frame generally includes: a Frame Control, a Duration, a RA, a TA, a body and a FCS. The Frame Control includes a Protocol Version, a Type, a Subtype, a to Distributed System (abbreviated as to DS), a From Distributed System (abbreviated as From DS), a More Frag, a Retry, a Power Mangent (abbreviated as Pwr Mgt), a More Data, a Protected Frame and an Order. The More Data field in the data frame sent from the node to the AP is rarely used, so the More Data field is reused as a “More Data/B_Nei Tab” herein, where B_Nei Tab represents the neighbor node list. For example, as shown in  FIG. 17 , the frame is a neighbor node list sent from the node to the AP in a case that “Type” is 10 and “Subtype” is 1101, where the body may be the one-way or two-way neighbor node list. It is indicated that the node sends a two-way neighbor node list in a case that the “More Data/B_Nei Tab” field is 1 and sends a one-way neighbor node list in a case that the “More Data/B_Nei Tab” field is 0. 
         [0170]    It should be understood that, the values of the foregoing fields are only examples and the disclosure is not limited thereto. 
         [0171]    In an embodiment of the disclosure, the AP may inform the node of the group that the node belongs to via a broadcast frame after determining the group that the node belongs to. 
         [0172]    The process of grouping provided according to the embodiment of the disclosure is described above, and the normal operation stage of the network after the nodes are grouped is described in detail below. 
         [0173]    In an embodiment of the disclosure, the method  300  may further include: 
         [0174]    sending to the node an access time period which only includes a CP, where the CP includes the access time divided for each group, so that the node may transmit data with the AP within the access time of the group that the node belongs to. 
         [0175]    In an embodiment of the disclosure, before sending to the node the access time period which only includes the CP, the method may further include: 
         [0176]    determining that there is a time idle of a sum of DIFS and CWmin in a channel 
         [0177]    In an embodiment of the disclosure, the CP may further include an access time which is not divided for any group, so that in a case that the node determines that the data is delay-sensitive service and transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period, the node may transmit the data with the AP within the access time which is not divided for any group in the first access time period. 
         [0178]    In an embodiment of the disclosure, the method  300  may further include: 
         [0179]    sending to the node a TIM frame, where the TIM frame carries information of the node which has cache downlink data at the AP in each group. 
         [0180]    The normal operation stage of the network after the grouping is described by the method  300 , and the details may refer to the description of the normal operation stage of the network in the method  200 , and detailed description thereof is omitted herein for concision. 
         [0181]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0182]    The method for grouping the node provided according to the embodiment of the disclosure is described from a perspective of the AP in conjunction with  FIG. 14  to  FIG. 17  as above, and the method for grouping the node provided according to the embodiment of the disclosure may be described in the following from a perspective of the first node. 
         [0183]      FIG. 18  illustrates a method for grouping a node provided according to an embodiment of the disclosure, which may be implemented by a node. As shown in  FIG. 18 , the method  400  includes steps  410 ,  420  and  430  as follows. 
         [0184]    S 410  may include sending to an AP a group joining request, so that the AP may send a first grouping poll to each node in a first set of nodes based on the group joining request and receive a first grouping acknowledgement sent from each node in a second set of nodes, where the first set of nodes is composed of the grouped node in nodes served by the AP, and the second set of nodes is composed of the node that monitors the group joining request in the first set of nodes. 
         [0185]    S 420  may include monitoring the first grouping acknowledgement sent from each node in the second set of nodes to the AP. 
         [0186]    S 430  may include sending a two-way neighbor node list to the AP, where the two-way neighbor node list includes a third set of nodes which is composed of the node corresponding to the first grouping acknowledgement that is monitored. 
         [0187]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0188]    In addition, in an embodiment of the disclosure, the neighbor node information may be collected completely by monitoring the grouping acknowledgement sent from the polled node to the AP, thereby reducing the probability of hidden terminals. 
         [0189]    In an embodiment of the disclosure, the first grouping poll and the first grouping acknowledgement are carried in a Type field, a Subtype field and a More Data field included in the control frame. 
         [0190]    In an embodiment of the disclosure, the sending the two-way neighbor node list to the AP in S 430  includes: 
         [0191]    sending to the AP the two-way neighbor node list carried in a data frame, where a Type field, a Subtype field and a More Data field in the data frame indicate that the data frame carries the two-way neighbor node list. 
         [0192]    The process of grouping provided according to the embodiment of the disclosure is described above, and the normal operation stage of the network after the nodes are grouped is described in detail below. 
         [0193]    In an embodiment of the disclosure, the method  400  may further include: 
         [0194]    receiving a message including an access time period sent from the AP, where the access time period only includes a CP, and the CP includes the access time divided for each group; 
         [0195]    determining the access time of the group that the node belongs to based on the access time period; and 
         [0196]    transmitting data with the AP within the access time of the group that the node belongs to. 
         [0197]    In an embodiment of the disclosure, the method  400  may further include: 
         [0198]    determining that the data is delay-sensitive service and transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period; and 
         [0199]    transmitting the data with the AP within an access time which is not divided for any group in the first access time period. 
         [0200]    In an embodiment of the disclosure, before transmitting the data with the AP within the access time of the group that the node belongs to, the method further includes: 
         [0201]    receiving a TIM frame sent from the AP, where the TIM frame carries information of the node which has cache downlink data at the AP in each group; and 
         [0202]    determining that there is downlink cache data at the AP based on the TIM frame. 
         [0203]    The normal operation stage of the network is described by the method  400 , the details may refer to the description of the normal operation stage of the network in the method  100 , and detailed description thereof is omitted herein for concision. 
         [0204]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor node with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0205]    The method for grouping the node provided according to the embodiment of the disclosure is described above in conjunction with  FIG. 1  to  FIG. 18 , and then a node and an AP provided according to embodiments of the disclosure are described in the following in conjunction with  FIG. 19  to  FIG. 29 . 
         [0206]      FIG. 19  is a schematic block diagram of a node  500  provided according to an embodiment of the disclosure. As shown in  FIG. 19 , the node  500  includes: 
         [0207]    a first receiving module  510 , configured to receive a grouping request sent from an AP; 
         [0208]    a first acquisition module  520 , configured to acquire a RSSI based on the grouping request received by the first receiving module  510 ; and 
         [0209]    a second acquisition module  530 , configured to acquire an ID of a group that the node belongs to determined based on the RSSI acquired by the first acquisition module. 
         [0210]    Therefore, for the node provided according to the embodiment of the disclosure, by grouping the node based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0211]    Optionally, as shown in  FIG. 20 , the node  500  provided according to an embodiment of the disclosure further includes: 
         [0212]    a first sending module  540 , configured to send the RSSI to the AP before the ID of the group that the node belongs to is determined based on the RSSI acquired by the first acquisition module  520 . 
         [0213]    Correspondingly, the second acquiring module  530  includes: 
         [0214]    a first receiving unit  534 , configured to receive a message including the ID of the group sent from the AP, where the ID of the group is determined by the AP based on the RSSI sent from the first sending module  540  and a preset RSSI grouping range; and 
         [0215]    a first acquisition unit  538 , configured to acquire the ID of the group from the message including the ID of the group received by the second receiving unit  534 . 
         [0216]    Optionally, the second acquisition module  530  is configured to: 
         [0217]    determine the ID of the group that the node belongs to based on the RSSI acquired by the first acquisition module  520  and the preset RSSI grouping range. 
         [0218]    Correspondingly, as shown in  FIG. 20 , the node  500  further includes: 
         [0219]    a second sending module  550 , configured to send to the AP the message including the ID of the group acquired by the second acquisition module  530 . 
         [0220]    Optionally, the first receiving module  510  is configured to: 
         [0221]    receive the grouping request indicated by a beacon frame and sent from the AP, where the body of the beacon frame carries the preset RSSI grouping range. 
         [0222]    Optionally, the second sending module  550  is configured to: 
         [0223]    send to the AP the message including the ID of the group within a period of time determined based on the ID of the group, a Distributed Coordination Function Inter-frame Space (DIFS) and a minimum value of Contention Window (CW) CWmin or within a preset Contention Period (CP). 
         [0224]    In an embodiment of the disclosure, signaling conflict may be reduced by decentralizing the time when the node reports the ID of the group that the node belongs to. 
         [0225]    Optionally, as shown in  FIG. 21 , the node  500  further includes: 
         [0226]    a third receiving module  561 , configured to receive a message including an access time period sent from the AP, where the access time period only includes a CP, and the CP includes the access time divided for each group; 
         [0227]    a first determining module  562 , configured to determine the access time of the group that the node belongs to based on the access time period received by the third receiving module  561 ; and 
         [0228]    a first transmitting module  563 , configured to transmit data with the AP within the access time of the group that the node belongs to determined by the first determining module  562 . 
         [0229]    Therefore, in the disclosure, the access time period only includes the CP, thereby avoiding the CFP in the conventional technology, taking full use of time, and reducing the time cost. 
         [0230]    Optionally, as shown in  FIG. 21 , the node  500  further includes: 
         [0231]    a second determining module  564 , configured to determine that the data transmitted by the first transmitting module  563  is delay-sensitive service, and transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period; and 
         [0232]    a second transmitting module  565 , configured to transmit the data with the AP within the access time which is not divided for any group in the first access time period. 
         [0233]    Therefore, in an embodiment of the disclosure, the average end-to-end transmission delay of the delay-sensitive service may be reduced effectively by setting a time for transmitting delay-sensitive service in the CP. 
         [0234]    Optionally, as shown in  FIG. 21 , the node  500  further includes: 
         [0235]    a fourth receiving module  566 , configured to receive a TIM frame sent from the AP before the data is transmitted to the AP within the access time of the group that the node belongs to, where the TIM frame carries information of the node which has cache downlink data at the AP in each group; and 
         [0236]    a third determining module  567 , configured to determine that there is downlink cache data at the AP based on the TIM frame received by the fourth receiving module  566 . 
         [0237]    The node  500  provided according to the embodiment of the disclosure may correspond to the node in the method  100  for grouping the node provided according to the embodiment of the disclosure, and the foregoing and other operations and/or functions of modules in the node  500  can realize the corresponding processes in the method  100  shown in  FIG. 1  to  FIG. 10 , and detailed description thereof is omitted herein. 
         [0238]    Therefore, for the node provided according to the embodiment of the disclosure, by grouping the nodes based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0239]    The node  500  provided according to the embodiment of the disclosure is described above in conjunction with  FIG. 19  to  FIG. 21 . An access point  600  provided according to an embodiment of the disclosure is described below in conjunction with  FIG. 22  to  FIG. 23 . 
         [0240]      FIG. 22  is a schematic block diagram of an access point  600  provided according to an embodiment of the disclosure. As shown in  FIG. 22 , the access point  600  includes: 
         [0241]    a first sending module  610 , configured to send to a node a grouping request, so that the node acquires a Received Signal Strength Indicator (RSSI) based on the grouping request; and 
         [0242]    a first acquisition module  620 , configured to acquire an ID of a group that the node belongs to determined based on the RSSI. 
         [0243]    Therefore, for the access point provided according to the embodiment of the disclosure, by grouping the nodes based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0244]    Optionally, as shown in  FIG. 23 , the first acquisition module  620  includes: 
         [0245]    a first receiving unit  624 , configured to receive a message including the ID of the group sent from the node, where the ID of the group is determined by the node based on the RSSI and a preset RSSI grouping range; and 
         [0246]    a first acquisition unit  628 , configured to acquire the ID of the group from the message including the ID of the group received by the first receiving unit  624 . 
         [0247]    Optionally, as shown in  FIG. 23 , the AP  600  further includes: 
         [0248]    a first receiving module  644 , configured to receive the RSSI sent from the node before the ID of the group that the node belongs to determined based on the RSSI is acquired by the first acquisition module. 
         [0249]    Correspondingly, the first acquisition module  620  is configured to: 
         [0250]    determine the ID of the group that the node belongs to based on the RSSI received by the second receiving module  644  and the preset RSSI grouping range. 
         [0251]    Correspondingly, as shown in  FIG. 23 , the AP  600  further includes: 
         [0252]    a second sending module  648 , configured to send to the node a message including the ID of the group acquired by the first acquisition module  620 . 
         [0253]    Optionally, the first sending module  610  is configured to: 
         [0254]    send to the node a grouping request indicated by a beacon frame, where the beacon frame carries the preset RSSI grouping range. 
         [0255]    Optionally, as shown in  FIG. 24 , the AP  600  further includes: 
         [0256]    a third sending module  652 , configured to send to the node an access time period which only includes a CP, where the CP include the access time divided for each group, so that the node may transmit data with the AP within the access time of the group that the node belongs to. 
         [0257]    Therefore, in the disclosure, the access time period only includes the CP, thereby avoiding the CFP in the conventional technology, taking full use of time, and reducing the time cost. 
         [0258]    Optionally, as shown in  FIG. 24 , the AP  600  further includes: 
         [0259]    a first determining module  654 , configured to determine there is a time idle of a sum of Distributed Coordination Function Inter-frame Space (DIFS) and a minimum value of Contention Window (CW) CWmin in a channel before the access time period which only includes the CP is sent from the third sending module  652  to the node. 
         [0260]    Therefore, the grouping access time may be reset in a case that there is an idle in the group, thereby taking full use of time and reducing the time cost. 
         [0261]    Optionally, the CP may further include an access time which is not divided for any group, so that in a case that the node determines that the data is delay-sensitive service and the transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period, the node may transmit the data with the AP within the access time which is not divided for any group in the first access time period. 
         [0262]    Therefore, in an embodiment of the disclosure, the average end-to-end transmission delay of the delay-sensitive service may be reduced effectively by setting a time for transmitting the delay-sensitive service in the CP. 
         [0263]    Optionally, as shown in  FIG. 24 , the AP  600  further includes: 
         [0264]    a fourth sending module  656 , configured to send to the node a Traffic Indication Map (TIM) frame, where the TIM frame carries information of the node which has cache downlink data at the AP in each group. 
         [0265]    The AP  600  provided according to the embodiment of the disclosure may correspond to the AP in the method  200  for grouping the node provided according to the embodiment of the disclosure, and the foregoing and other operations and/or functions of modules in the AP  600  can realize the corresponding processes in the method  200  shown in  FIG. 11  to  FIG. 13 , and detailed description thereof is omitted herein for concision. 
         [0266]    Therefore, for the AP provided according to the embodiment of the disclosure, by grouping the nodes based on the RSSI, the problems such as contention conflict and low network efficiency in the large scale network may be solved, and unfair throughput caused by near-far effect may be avoided, thereby reducing the probability of hidden terminals. 
         [0267]    An AP  700  provided according to an embodiment of the disclosure is described below in conjunction with  FIG. 25  to  FIG. 27 . 
         [0268]      FIG. 25  is a schematic block diagram of an AP  700  provided according to an embodiment of the disclosure. As shown in  FIG. 25 , the AP  700  includes: 
         [0269]    a first receiving module  710 , configured to receive a group joining request sent from a first node; 
         [0270]    a first sending module  720 , configured to send a first grouping poll to each node in a first set of nodes based on the group joining request received by the first receiving module  710 , where the first set of nodes is composed of grouped nodes in nodes served by the AP; 
         [0271]    a second receiving module  730 , configured to receive a first grouping acknowledgement sent from each node in a second set of nodes, where the second set of nodes is composed of the node that monitors the group joining request sent from the first sending module  720  in the first set of nodes; 
         [0272]    a third receiving module  740 , configured to receive a two-way neighbor node list sent from the first node, where the two-way neighbor node list includes information of a third set of nodes which is composed of the node corresponding to the first grouping acknowledgement monitored by the first node; and 
         [0273]    a first grouping module  750 , configured to group the first node based on the two-way neighbor node list received by the third receiving module  740 . 
         [0274]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0275]    Optionally, as shown in  FIG. 26 , the AP  700  includes: 
         [0276]    a second sending module  762 , configured to send a second grouping poll to each node in the first set of nodes before the group joining request sent from the first node is received by the first receiving node  710 , so that the second node, which may be any node in the first set of nodes, may send a second grouping acknowledgement to the AP, and the node that monitors the second grouping poll and the second grouping acknowledgement in the first set of nodes may record information of the second node into its one-way neighbor node list; 
         [0277]    a fourth receiving module  764 , configured to receive the one-way neighbor node list sent from each node in the first set of nodes; and 
         [0278]    a second grouping module  766 , configured to group the first set of nodes based on the one-way neighbor node list received by the fourth receiving module  764 , where the nodes in each group are neighbor nodes with each other. 
         [0279]    Therefore, in the embodiment of the disclosure, the time cost of grouping may be reduced by grouping multiple nodes at a time and grouping a single node independently. 
         [0280]    Optionally, the fourth receiving unit  764  is configured to: 
         [0281]    receive the one-way neighbor node list which is sent from each node in the first set of nodes in an order that the second grouping poll sent from the second sending module  762  is received. 
         [0282]    Optionally, the first sending module  720  is configured to: 
         [0283]    send to each node in the first set of nodes, the first grouping poll indicated by a Type field, a Subtype field and a More Frag file included in a control frame. 
         [0284]    The second receiving module  730  is configured to: 
         [0285]    receive the first grouping acknowledgement sent from each node in the second set of nodes to the AP and indicated by the Type field, the Subtype field and the More Frag field included in the control frame. 
         [0286]    The third receiving module  740  is configured to: 
         [0287]    receive the two-way neighbor node list carried in the data frame and sent from the first node, where the Type field, the Subtype field and the More Data field in the data frame indicate that the data frame carries the two-way neighbor node list. 
         [0288]    Optionally, the second sending module  762  is configured to: 
         [0289]    send, to each node in the first set of nodes, the second grouping poll indicated by a Type field, a Subtype field and a More Frag field included in a control frame. 
         [0290]    The second grouping acknowledgement is indicated by a Type field, a Subtype field and a More Frag field included in a control frame. 
         [0291]    The fourth receiving module  764  is configured to: 
         [0292]    receive the one-way neighbor node list carried in the data frame and sent from each node in the first set of nodes, where the Type field, the Subtype field and the More Data field in the data frame indicate that the data frame carries the one-way neighbor node list. 
         [0293]    Optionally, as shown in  FIG. 27 , the AP  700  further includes: 
         [0294]    a third sending module  772 , configured to send to the node an access time period which only includes a CP, where the CP includes the access time divided for each group, so that the node may transmit data with the AP within the access time of the group that the node belongs to. 
         [0295]    Therefore, in the disclosure, the access time period only includes the CP, thereby avoiding the CFP in the conventional technology, taking full use of time, and reducing the time cost. 
         [0296]    Optionally, as shown in  FIG. 27 , the AP  700  further includes: 
         [0297]    a first determining module  774 , configured to determine a time idle of a sum of Distributed Coordination Function Inter-frame Space (DIFS) and a minimum value of Contention Window (CWmin) in a channel before the access time period which only includes the CP is sent from the third sending module  772  to the node. 
         [0298]    Therefore, the grouping access time may be reset in a case that there is an idle in the group, thereby taking full use of time and reducing the time cost. 
         [0299]    Optionally, the CP may further include an access time which is not divided for any group, so that in a case that the node determines that the data is delay-sensitive service and the transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period, the node may transmit data with the AP within the access time which is not divided for any group in the first access time period. 
         [0300]    Therefore, in the embodiment of the disclosure, the average end-to-end transmission delay of the delay-sensitive service may be reduced effectively by setting a time for transmitting the delay-sensitive service in the CP. 
         [0301]    Optionally, as shown in  FIG. 27 , the AP  700  further includes: 
         [0302]    a fourth sending module  774 , configured to send to the node a Traffic Indication Map (TIM) frame, where the TIM frame carries information of the node which has cache downlink data at the AP in each group. 
         [0303]    The AP  700  provided according to the embodiment of the disclosure may correspond to the AP in the method  300  for grouping the node provided according to the embodiment of the disclosure, and the foregoing and other operations and/or functions of modules in the AP  700  can realize the corresponding processes in the method  300  shown in  FIG. 14  to  FIG. 17 , and detailed description thereof is omitted herein for concision. 
         [0304]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0305]      FIG. 28  is a schematic block diagram of a node  800  provided according to an embodiment of the disclosure. As shown in  FIG. 28 , the node  800  includes: 
         [0306]    a first sending module  810 , configured to send to an AP a group joining request, so that the AP may send a first grouping poll to each node in a first set of nodes based on the group joining request and receive a first grouping acknowledgement sent from each node in a second set of nodes, where the first set of nodes is composed of grouped nodes in nodes served by the AP, and the second set of nodes is composed of the node that monitors the group joining request in the first set of nodes; 
         [0307]    a first monitoring module  820 , configured to monitor the first grouping acknowledgement sent from each node in the second set of nodes to the AP; and 
         [0308]    a second sending module  830 , configured to send a two-way neighbor node list to the AP, where the two-way neighbor node list includes a third set of nodes which is composed of a node corresponding to the first grouping acknowledgement monitored by the first monitoring module  820 . 
         [0309]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0310]    Optionally, the first grouping poll and the first grouping acknowledgement are indicated by the Type field, the Subtype field and the More Data field included in the control frame. 
         [0311]    The second sending module  830  is configured to: 
         [0312]    send to the AP the two-way neighbor node list carried in the data frame, where the Type field, the Subtype field and the More Data field in the data frame indicate that the data frame carries the two-way neighbor node list. 
         [0313]    Optionally, as shown in  FIG. 29 , the node  800  further includes: 
         [0314]    a third receiving module  831 , configured to receive a message including an access time period sent from the AP, where the access time period only includes a CP, and the CP includes the access time divided for each group; 
         [0315]    a first determining module  832 , configured to determine the access time of the group that the node belongs to based on the access time period received by the third receiving module  562 ; and 
         [0316]    a first transmitting module  833 , configured to transmit data with the AP within the access time of the group that the node belongs to determined by the first determining module  564 . 
         [0317]    Therefore, in the disclosure, the access time period only includes the CP, thereby avoiding the CFP in the conventional technology, taking full use of time, and reducing the time cost. 
         [0318]    Optionally, as shown in  FIG. 29 , the node  800  further includes: 
         [0319]    a second determining module  834 , configured to determine that the data transmitted by the first transmitting module  833  is delay-sensitive service and transmission of the data is not completed within the access time of the group that the node belongs to in a first access time period; and 
         [0320]    a second transmitting module  835 , configured to transmit data to the AP within the access time which is not divided for any group in the first access time period. 
         [0321]    Therefore, in the embodiment of the disclosure, the average end-to-end transmission delay of the delay-sensitive service may be reduced effectively by setting a time for transmitting the delay-sensitive service in the CP. 
         [0322]    Optionally, as shown in  FIG. 29 , the node  800  further includes: 
         [0323]    a fourth receiving module  836 , configured to receive a Traffic Indication Map (TIM) frame sent from the AP before the data is transmitted to the AP within the access time of the group that the node belongs to, where the TIM frame carries information of the node which has cache downlink data at the AP in each group; and 
         [0324]    a third determining module  837 , configured to determine that there is downlink cache data at the AP based on the TIM frame received by the fourth receiving module  836 . 
         [0325]    The node  800  provided according to the embodiment of the disclosure may correspond to the node in the method  400  for grouping the node provided according to the embodiment of the disclosure, and the foregoing and other operations and/or functions of modules in the node  800  can realize the corresponding processes in the method  400  shown in  FIG. 18 , and detailed description thereof is omitted herein for concision. 
         [0326]    Therefore, in the method for grouping the node provided according to the embodiment of the disclosure, nodes in each group are neighbor nodes with each other by grouping the node based on the two-way neighbor node list of the node, thereby reducing the probability of hidden terminals in the large scale network and solving the problems such as contention conflict and low network efficiency. 
         [0327]    It may be understood by those skilled in the art that, the units and algorithm steps disclosed in the embodiment of the disclosure may be realized by electronic hardware or integration of computer software and electronic hardware. Whether the functions are implemented by electronic hardware or by integration of computer software and electronic hardware is determined based on the specific application and the design constrains of the technical solution. Those skilled in the art may adopt different ways to realize the described functions for each specific application, and the implementation is within the protection scope of the disclosure. 
         [0328]    It may be understood by those skilled in the art that, the working process of the foregoing system, apparatus and unit may refer to the corresponding process described in the foregoing method embodiments, and detailed description thereof is omitted herein. 
         [0329]    It may be understood that, the disclosed system, apparatus and method provided in the embodiments of the application may be realized in other ways. For example, the apparatus set forth is only an illustrative example. For example, the division of units is only a logical function division, and there may be other divisions in implementation. For example, multiple units or components may be combined or integrated into another system, and certain features may be omitted or not be implemented. In addition, a coupling or a direct coupling or a communication connection described may be an indirect coupling or communication connection via a certain interface, apparatus or unit, which may be an electronic or a mechanical coupling or communication connection, for example. 
         [0330]    The units which are described as separated components may be or not be separated physically, and components which are illustrated as units may be or not be physical units, i.e., may be located in a certain position or be distributed in multiple network units. Part or all of the units may be adopted to realize the purpose of the embodiment according to actual needs. 
         [0331]    In addition, the functional units in the embodiments of the disclosure may be integrated into a processing unit or may be independent from each other, and two or more units may be integrated into one unit. 
         [0332]    The functions may be stored in a computer-readable storage medium in a case that the functions are realized via a software function unit and are sold and used as an independent product. In view of this, the essential technical solution of the disclosure or the part of the disclosure which contributes to the prior art or part of the technical solution may be implemented by a software product. The computer software product may be stored in a storage medium and includes several instructions, to enable a computer device (for example, a personal computer, a server or a network device) to implement all or part of steps of the method provided according to each embodiment of the disclosure. The foregoing storage medium includes medium which can store program codes, such as a USB flash disk, a mobile hard disk drive, a Read-Only Memory (ROM), a Random Access Memory (RAM), a diskette or an optical disk. 
         [0333]    The above are only embodiments of the invention, and the protection scope of the invention is not limited thereto. Modifications and substitutions which can be made by those skilled in the art without any creative work within the technical scope of the disclosure all belong to the protection scope of the invention. Therefore, the protection scope of the invention is interpreted by the claims.