WO2012060781A1 - Dispositifs de communication dans un réseau et procédé de commande d'un dispositif de communication - Google Patents

Dispositifs de communication dans un réseau et procédé de commande d'un dispositif de communication Download PDF

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Publication number
WO2012060781A1
WO2012060781A1 PCT/SG2011/000390 SG2011000390W WO2012060781A1 WO 2012060781 A1 WO2012060781 A1 WO 2012060781A1 SG 2011000390 W SG2011000390 W SG 2011000390W WO 2012060781 A1 WO2012060781 A1 WO 2012060781A1
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Prior art keywords
message
communication device
communication devices
communication
access control
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PCT/SG2011/000390
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English (en)
Inventor
Haiguang Wang
Jaya Shankar Pathmasuntharam
Zhongding Lei
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Agency For Science, Technology And Research
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • H04W74/0825—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA] with collision detection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/18—Processing of user or subscriber data, e.g. subscribed services, user preferences or user profiles; Transfer of user or subscriber data
    • H04W8/186—Processing of subscriber group data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/26—Network addressing or numbering for mobility support

Definitions

  • Various embodiments generally relate to the field of communication devices in a network and methods for controlling a communication device.
  • the IEEE 802.11 communication standard has been widely used for short range wireless network access. It is a complementary technology to the wired Local Area Network (LAN). However, compared to the wired communication, there are more challenges when using the wireless technology. For example, hidden terminal may be one such challenge.
  • the 802.1 1 communication standard uses Carrier Sensing Multiple Access / Collision Avoidance (CSMA/CA) to avoid collision. Request- to-Send (RTS) and Clear-to-Send (CTS) are used for media reservation. Nodes within the transmission range of source or destination are not allowed to transmit before the current transmission finished.
  • CSMA/CA Carrier Sensing Multiple Access / Collision Avoidance
  • RTS Request- to-Send
  • CTS Clear-to-Send
  • FIG. 1 illustrates a basic view of the IEEE 802.11 technology in terms of (a) its topology and (b) its timeline transmission activities.
  • the exemplary IEEE 802.11 network 100 of Figure 1(a) comprises a number of communication devices which may be a source (SRC) 102, a destination (DEST) 104 and others 106, such as a plurality of communication devices.
  • the SRC 102 may send out a Request-to-Send (RTS) message or signal or packet 108.
  • RTS Request-to-Send
  • This RTS message 108 may be received by communication devices located within an area 112.
  • the DEST 104 is one of these communication devices within the area 1 12, it will send a reply Clear-to-Send (CTS) message or signal or packet 1 10.
  • CTS Clear-to-Send
  • This CTS message 1 10 may be received by communication devices located within an area 114. As the SRC 102 is located within the area 114, the CTS message 1 10 is received by the SRC 102. The SRC 102 can then reserve channel time for data transmission with the DEST 104. As the others 106 are not responsive to the RTS message 108, they will not reply any CTS messages to the SRC 102. Therefore, no data transmission is performed between the SRC 102 and the others 106.
  • FIG 1(b) shows various transmission activities in the exemplary IEEE 802.11 network 100 of Figure 1(a) with respect to time 116. Time increases from left to right.
  • DCF Distributed Coordinate Functioning
  • the SRC 102 senses the status of the wireless medium or channel before transmitting. If the channel is continuously idle for DCF Interframe Space (DIFS) 120 duration, only then it is supposed to transmit a frame, in this case, containing the RTS message 108. If the channel is busy during the DIFS interval, the SRC 102 will defer its transmission (not shown in Figure 1(b)).
  • DIFS DCF Interframe Space
  • the DEST 104 Upon receiving the RTS message 108, the DEST 104 waits for a Short Interframe Space (SIFS) 122 before acknowledging with the CTS message 110. After receiving CTS, the SRC 102 waits for a SIFS 122 and then sends data 124 to the DEST 104. Once the data 124 is received, the DEST 104 waits for a SIFS 122 before sending an acknowledgement (ACK) frame 126.
  • SIFS Short Interframe Space
  • NAV Network Allocation Vector
  • RTS Network Allocation Vector
  • the NAV is virtual carrier sensing mechanism used with wireless network protocols such as IEEE 802.11.
  • the virtual carrier sensing is a logical abstraction which limits the need for physical carrier sensing at the air interface in order to save power.
  • the NAV can be seen as a counter, which counts down to zero at a uniform rate. When the counter is zero, the virtual carrier sensing indication is that the medium is idle and when nonzero, the indication is busy.
  • NAV NAV
  • An on-going IEEE 802.1 lac or equivalent standard focuses on applying Multi- User Multi-Input- Multi-Output (MU-MIMO) technology in 802.1 1 based communication technology.
  • MU-MIMO Multi- User Multi-Input- Multi-Output
  • an 802.11 access point can send data to a few stations at the same time.
  • AP 802.11 access point
  • one of the challenges is the way of protecting data transmission over the IEEE 802.1 lac MU-MIMO downlink as the traditional RTS/CTS scheme cannot provide a complete protection over the transmission.
  • an access point (AP) 200 supports IEEE 802.1 lac technology. It has three stations, STA1 202, STA2 204 and STA3 206 attached to it.
  • the AP 200 wants to transmit data to STA1 202, STA2 204 and STA3 206 simultaneously with 802.1 lac MU-MIMO technology via a MU-MIMO downlink 208, an area 208 shown in Figure 2 is to be completely protected. That is, for stations 202, 204, 206 in the area defined by an outer boundary 310, either an RTS or CTS message, or both should be received.
  • Figure 3 shows an area 300 protected by a traditional single RTS 302/CTS 304 message.
  • This protected area 300 is established by the RTS protection range 306 and the CTS protection range 308. It is observed that there are areas 310 which are not protected, as line-shaded in Figure 3. If a station STA4 312 is located in the unprotected areas 310 and if the STA4 312 is sending a signal 314 out to, for example, a different access point (AP2) 316, the signal 314 may also be received by a ST A3 318 which is located within the protected area 300. Collision 320 may also occur. Therefore, a scheme with more complete protection is necessary, especially when the data packets are long.
  • AP2 access point
  • An alternative method to protect data transmission from collision on 802.1 1 systems is to use a CTS-to-Self scheme as illustrated in Figure 4, where an API 400 will send a CTS message 402 when it needs to send downlink packets 404 without receiving a RTS message first.
  • this method can only provide protection within the coverage of the AP as defined by an area of CTS-to Self protection range 406. That is to say, for example, if a station STA4 408 is located outside the protected area 406 and if the STA4 408 is sending a signal 410 out to, for example, a different access point (AP2) 412, the signal 410 may also be received by a STA3 414 which is located within the protected area 406. Further, the drawback of such a protection is that it takes a longer time to transmit the same amount of data; thereby reducing the effective throughput.
  • AP2 access point
  • the protection range provided by the CTS-to-Self scheme as described in Figure 4 is limited and also, it can only help in ACK protection instead of data transmission. This is because even if the CTS-to-Self scheme may collide with other transmissions, the data transmission proceeds as scheduled as seen between the STA3 414 and the STA4 408 of Figure 4. In contrast, the RTS/CTS protection for example, as described in Figure 3, data transmission will not proceed as scheduled when RTS or CTS is not transmitted or received properly.
  • the protected area is also less than the required complete protection area as seen in Figure 2. However, it is larger than the area protected by the CTS-to-Self scheme of Figure 4.
  • RTS/CTS can filter out part of potential collision in data transmission part. When they are not transmitted or received properly by the source or destination, data packet will not be transmitted. Instead, the source waits for future opportunity to do RTS/CTS transaction again.
  • the scheme uses single RTS multiple CTS method.
  • the name implies, after the AP sends out a RTS message, desired reception stations may send back CTS messages either sequentially or simultaneously.
  • Figure 5 and Figure 6 show the two possible way of CTS transmission of sending CTS packets sequentially or simultaneously, respectively. In Figures 5 and 6, time increases from left to right. Sending multiple CTS packets back sequentially is easier in design and implementation.
  • the SIFS may also include reduced interframe space (RIFS) 500.
  • RIFS reduced interframe space
  • RIFS reduced interframe space
  • L-SIG legacy signal
  • H-SIG high throughput signal field
  • the HT-SIG 506 is used to carry information required to interpret the high throughput packet formats.
  • the acknowledgement (ACK) frames may be block acknowledgements (BA) for example, BA1 508, BA2 510 and BA3 512 of Figure 5.
  • each of the intervals between the RTS message 600 and the CTS message 602 is based on an interframe space (xIFS) time 604.
  • xIFS interframe space
  • the IEEE 802.1 lac defines a new technology for the data transmission with Wireless Local Area Networks (WLAN). Different from a traditional WLAN technology, MU-MIMO technology is applied in the design and multiple data packets are allowed to transmit to multiple stations simultaneously. This feature makes the transmission protection provided by traditional RTS/CTS schemes incomplete.
  • the present invention relates to a communication device for a network, the communication device comprising a message generating circuit configured to generate a message for sending to each of a plurality of communication devices in the network, wherein the message comprises a Media Access Control address associated with the plurality of communication devices, and a transmitter configured to send the message to each of the plurality of communication devices.
  • the present invention relates to a method for controlling a communication device in a network, the method comprising generating a message for sending to each of a plurality of communication devices in the network, wherein the message comprises a Media Access Control address associated with the plurality of communication devices, and sending the message to each of the plurality of communication devices.
  • the present invention also relates to a communication device for a network, the communication device comprising a receiver configured to receive a message comprising a Media Access Control address associated with a plurality of communication devices in the network, a determining unit configured to determine whether the communication device is part of the plurality of communication devices, and a processor configured to process the message as a message addressed to the communication device if it is determined that the communication device is part of the plurality of communication devices.
  • the present invention relates to a method for controlling a communication device in a network, the method comprising receiving a message comprising a Media Access Control address associated with a plurality of communication devices in the network, determining whether the communication device is part of the plurality of communication devices, and processing the message as a message addressed to the communication device if it is determined that the communication device is part of the plurality of communication devices.
  • Figure 1 shows a schematic view of the IEEE 802.11 technology in terms of (a) its topology and (b) its timeline transmission activities;
  • Figure 2 shows a schematic topological view of a complete protection required for MU-MIMO downlink
  • Figure 3 shows a schematic topological view of an area protected by single RTS/CTS scheme
  • Figure 4 shows a schematic topological view of a protection range achieved with CTS-to-Self messages
  • Figure 5 shows a schematic timeline-based view of transmission activities of a single RTS with multiple CTS being sent sequentially
  • Figure 6 shows a schematic timeline-based view of transmission activities of a single RTS with multiple CTS being sent simultaneously;
  • Figure 7 shows a schematic block diagram of a communication device, in accordance to various embodiments.
  • Figure 8 shows a representation of a RTS packet format, in accordance to various embodiments.
  • Figure 9 shows a representation of a CTS packet format, in accordance to various embodiments.
  • Figure 10 shows a representation of a RTS-to-Self format, in accordance to various embodiments
  • Figure 11 shows a schematic block diagram of a communication device, in accordance to various embodiments.
  • Figure 12 shows a schematic topological view of an example of an AP detecting conflict between Group ID and MAC address, in accordance to various embodiments;
  • Figure 13 shows a schematic topological view of another example of an AP detecting conflict between Group ID and MAC address, in accordance to various embodiments
  • Figure 14 shows a schematic topological view of an example of an AP using a group ID directly as a group MAC address, in accordance to various embodiments
  • Figure 15 shows a schematic topological view of an example of handling a lost CTS message, in accordance to various embodiments
  • Figure 16 shows a schematic block diagram of a method of controlling a communication device in a network, in accordance to various embodiments
  • Figure 17 shows a schematic block diagram of a communication device, in accordance to various embodiments.
  • Figure 18 shows a schematic block diagram of a communication device, in accordance to various embodiments.
  • Figure 19 shows a schematic block diagram of a method of controlling a communication device in a network, in accordance to various embodiments.
  • a communication device for a network comprises a message generating circuit 702 configured to generate a message for sending to each of a plurality of communication devices in the network, wherein the message comprises a Media Access Control address associated with the plurality of communication devices; and a transmitter 704 configured to send the message to each of the plurality of communication devices.
  • association with may refer to having a link to or establishing a relationship with.
  • association with may be interchangably referred as “assigned to”, or “having”, or “belong to”, or “allocated to”.
  • MAC address refers to a unique identifier assigned to network interfaces for communications on the physical network segment.
  • MAC addresses are used for numerous network technologies and most IEEE 802 network technologies including Ethernet.
  • MAC addresses are used in the Media Access Control protocol sub-layer of the OSI reference model.
  • the term "communication device” may for example refer to a machine that assists data transmission, that is sending and/or receiving data information.
  • a communication device may be, for example but not limited to, a station, or a base station, or a substation, or an access point, or a modem, a cable, or a port.
  • the communication device 700 may comprise an access point of a wireless communication network.
  • the plurality of communication devices may be referred to as a plurality of stations.
  • the term "network” refers to a communication network or a wireless communication network.
  • the network may be a IEEE 802 network.
  • the term "message” generally refers to a short information sent from one entity to at least another one entity.
  • a message may be a packet or a cluster.
  • a media reservation may be established between a communication device 700, for example, an access point and its targeted plurality of communication devices, for example, a plurality of stations.
  • the communication device 700 may generate and send a message to the plurality of communication devices to initiate the media reservation. Any of the plurality of communication devices may also initiate the media reservation by generating and sending a message to the communication device 700.
  • An identifier or a multicast identifier such as a Media Access Control address may be appended in the message so that a communication device or a station receiving the message can check whether it is associated with this address, for example, whether it is of the same address. If so, the message may be meant for this communication device as a recipient and the recipient may check the rest of the message and react to it accordingly. If the communication device or the station is not associated with the address, it may mean that this communication device or station may not be an intended recipient and it may not react to the message.
  • the message may contain requests and information that is necessary for at least establishing, maintaining and terminating the communication link.
  • the message may indicate that the communication device is ready to send data to each of the plurality of communication devices in the network.
  • the message may a Request-to-Send message.
  • FIG. 8 shows a Request-to-Send (RTS) packet format.
  • a RTS packet format 800 comprises an about 16 ⁇ preamble 802, followed by an about 10 ⁇ Physical Layer Convergence Procedure (PLCP) frame 804, a typically 20-octet RTS Media Access Control (MAC) frame 806, followed by a typically 6-bit tail 808 and a pad or padding field 810 for proving proper spacing.
  • PLCP Physical Layer Convergence Procedure
  • MAC Media Access Control
  • the RTS MAC frame 806 comprises a 2-octet frame control (FC) 812, a 2-octet duration ID 814, a 6-octet receiver address (RA) 816, a 6-octet transmitter or send address (TA) 818 and a 4-octet frame check sequence (FCS) 820.
  • FC 2-octet frame control
  • RA 6-octet receiver address
  • TA 6-octet transmitter or send address
  • FCS 4-octet frame check sequence
  • Group addressing with pre-allocated MAC Address from IEEE MAC Address Space is provided.
  • the simplest scheme is to assign a group MAC address and notify the stations within the group about the assignment. Then this address is used in the RTS message.
  • the stations in the group can react, for example, to send or not to send a Clear-to-Send (CTS) message, based on their respective configurations.
  • CTS Clear-to-Send
  • a group MAC address may only be assigned to one group of stations associated with an access point (AP).
  • the same group MAC address may be assigned to groups under a different AP if the stations in those groups have both the group MAC address and a transmitter address.
  • a station should only reply to a RTS message with a group MAC address sent by the AP it associates with. Therefore, a group can be uniquely identified by a group MAC address and the MAC address of the AP who assigns this group MAC address to it.
  • the Institute of Electrical and Electronic Engineering assigns a MAC address at a price of about S$550 for each block of 4096 MAC addresses.
  • a company or an individual may purchase and allow the AP produced/owned to use the MAC address for group communication.
  • an AP sends group MAC address information to the stations when they are included into a certain group. Therefore, different manufacturer or individual may have to pay for the MAC address.
  • the message may comprise a group address corresponding to the Media Access Control address.
  • the group address may be derived from a physical layer group address or may be assigned by an authoritative body such as the IEEE.
  • the group address may comprise a group ID.
  • the Media Access Control address may be mapped to the group ID.
  • the physical layer refers to the first layer of the Open Systems Interconnection model (OSI model), which is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communication system in terms of abstraction layers. Similar communication functions are grouped into logical layers.
  • OSI model Open Systems Interconnection model
  • group ID for use to identify the potential multiple reception stations for the current transmission at the physical layer.
  • a static mapping may be setup between the group ID and the MAC address.
  • the group ID 0x00 corresponds to a reserved group MAC address OxabcdOO
  • 0x01 corresponds to OxadcdOl and so on.
  • the addresses are in HEX representations.
  • a group MAC address may be allocated automatically or pre-allocated during the negotiation of the group ID for the physical layer. This simplifies the implementation.
  • an access point may transmit a RTS message with a group MAC address/group ID to the network and one or several stations belong to the group can send back a CTS message based on a predefined schedule.
  • This way to a single RTS message and multiple CTS messages are transmitted to protect the data transmission on the IEEE 802.1 lac MU-MIMO downlink.
  • This scheme provides an improved protection over the data transmission and an improved efficiency since not every station is required to send back a CTS message and therefore relieves a medium's or a channel's bandwidth for other data transmission.
  • the message may comprise a Clear-to-Send (CTS) message.
  • CTS Clear-to-Send
  • FIG 9 shows a representation of a CTS packet format.
  • the CTS packet format 900 comprises an about 16 ⁇ preamble 902, followed by an about 10 ⁇ PLCP frame 904, a typically 14-octet CTS MAC frame 906, followed by a typically 6-bit tail 908 and a pad or padding field 910 for proving proper spacing.
  • the CTS MAC frame 906 comprises a 2-octet FC 912, a 2-octet duration ID 914, a 6-octet RA 916, and a 4-octet FCS 918.
  • an AP may also send a CTS message with a group MAC address for acknowledgement (ACK) protection. Stations that are not in the group can give up the decoding of the following data packet.
  • ACK acknowledgement
  • the group ID may be used to directly for addressing in a RTS packet.
  • various embodiments provide the Media Access Control address of the communication device 700 being comprised in a receiver address field of the message.
  • the group address may be comprised in a transmitter address field of the message.
  • an AP may skip certain group ID and use other group IDs in group assignment.
  • a station in Ad Hoc Mode it may receive a RTS message with a group ID which is the same its own MAC address. If the station in Ad Hoc mode sends back a CTS message, then collision may happen. To avoid this from occurring, a RTS-to-Self scheme is used instead of a normal RTS scheme to allow multiple CTS messages be sent back from the stations.
  • the RA field 1000 in the RTS message 1002 is set to the MAC address of the AP 1004 and the TA field 1006 of the RTS packet 1002 is set to group ID 1008 as illustrated in Figure 10 showing a representation of the format of the RTS-to-Self message.
  • the stations associate to this AP, they will know that the RTS message 1002 is sent to a group of stations and the stations in the group may send back a CTS message to the AP.
  • the station with MAC address the same as group ID it will not send back a CTS message when receiving RTS-to-Self messages, for example, similar to the RTS message 1002 as it is not the intended receiver.
  • the message may request each communication device of the plurality of communication devices to transmit a response message indicating that the respective communication device of the plurality of communication devices is ready to receive the data.
  • the respective communication device of the plurality of communication devices may refer to one or more of the plurality of communication devices.
  • the message may be transmitted according to a communication protocol according to which the plurality of communication devices transmit respective response messages in response to the message, wherein each of the response messages indicates that the respective communication device of the plurality of communication devices is ready to receive the data.
  • the communication protocol may be, for example but not limited to, IEEE 802 protocol or IEEE 802.1 1 protocol or IEEE 802.1 lac protocol.
  • the response message may be a Clear-to-Send message.
  • each Clear-to-Send message may be sent one after another in sequence. This allows for balancing the overhead and protection.
  • the Clear-to-Send messages may be sent simultaneously.
  • the communication device 700 may further comprise a receiver 1100 configured to receive a message sent by any communication device in the network.
  • the communication device 700 may further comprise a determining unit 1102 for determining collision if the message received by the receiver is a Request-to-Send message with a transmitter address being the same as the Media Access Control address, the Request-to-Send message being sent by any communication device that is not associated with the Media Access Control address, or if the message received by the receiver 1 100 is a Clear-to-Send message sent by one of the plurality of communication devices associated with the Media Access Control address, wherein the Clear-to-Send message being sent is not in response to a Request-to-Send message sent by the communication device 700.
  • a determining unit 1102 for determining collision if the message received by the receiver is a Request-to-Send message with a transmitter address being the same as the Media Access Control address, the Request-to-Send message being sent by any communication device that is not associated with the Media Access Control address, or if the message received by the receiver 1 100 is a Clear-to-Send message sent by one of the plurality of communication devices associated with the Media
  • the message generating circuit 702 may be configured to generate a message for sending to each of the plurality of communication devices in the network, wherein the message comprises a different Media Access Control address associated with the plurality of communication devices.
  • the different Media Access Control address may be any Media Access Control address that is not the same as the Media Access Control address previously used or currently being used.
  • Figure 12 and Figure 13 show the scenario of the group ID and MAC address conflict detection.
  • an API 1200 receives a RTS message 1202 with a TA address that is the same as a group ID sent by STA4 1204, which is not associated with the plurality of communication devices, such as the STAl 1206, STA2 1208, and STA3 1210.
  • the API 1200 can therefore detect collision of group ID and MAC address.
  • a new (different) group ID will then be assigned to the group of STAl 1206, STA2 1208, and STA3 1210.
  • a STA3 1300 receives a RTS message 1302 with a TA address that is same as a group ID sent by STA4 1304, which is not associated with the plurality of communication devices, such as the STAl 1306, STA2 1308, and STA3 1300.
  • the STA3 1300 then sends a CTS message to a API 1310.
  • the API 1310 detects a collision of group ID and MAC address.
  • a new (different) group ID will then be assigned to the group of STAl 1306, STA2 1308, and STA3 1300.
  • every station in the group is to send a CTS message back to facilitate the detection.
  • the message received by the receiver 1 100 may be a notification signal sent by one of the plurality of communication devices, wherein the notification signal indicates whether a Clear-to-Send message is to be sent upon receiving a Request-to-Send message comprising the Media Access Control address.
  • the station can send a notification signal to notify the AP that it is not going to send a CTS message when receiving a RTS message to the group it belongs to.
  • the station may send a notification signal to indicate that a CTS message will be generated when receiving a RTS message for the group. Acknowledgement may be sent for confirmation of the change.
  • the AP should derive the duration value for NAV when sending a RTS message based on the number of CTS messages expected.
  • the term "notification signal" may be in the form of a message or a flag.
  • the message may be sent to each of the plurality of communication devices to establish a communication link for data transmission between the communication device 700 and the plurality of communication devices.
  • the communication device 700 as shown in Figure 1 1 may further comprise a transmitter 1104 configured to transmit the data after a predetermined time period after the transmission of the message.
  • the transmitter 1104 may be configured to transmit the data to the plurality of communication devices using MIMO.
  • the transmitter 1 104 may be configured to transmit different data to be sent to different communication devices of the plurality of communication devices in parallel.
  • the data may be transmitted according to a communication protocol requesting the plurality of communication devices to acknowledge receipt of the data.
  • the communication protocol may be as defined above.
  • Various embodiments and examples for group addressing in a RTS message allows an 802.1 lac AP to receive multiple CTS messages by sending one RTS message, and is compatible with legacy 802.11 stations. It also helps in energy saving because when stations receiving a RTS message with a group MAC address, if they are not in the group, they can stop listening to the channel until transmission activity ends. [0087] For selective CTS transmission, whether a CTS message is necessary for a given station depends on the environment. It only transmits when it senses that other 802.11 networks on the same channel are nearby and packet loss is non-negligible. Stations are allowed to send in messages to indicate whether a CTS message is necessary.
  • the AP When sending a RTS message, the AP checks the number of CTS messages required to send back and then set the duration value in the RTS packet accordingly. In the event that a station not belonging to the same group to be addressed by the AP (or more generally referred to as a non-station) indicates that a CTS message is necessary, the AP may either establish a RTS meassge (or a RTS-to-Self message) or a CTS-to-Self message for protection. A group address can also be put in a CTS-to-Self message.
  • a first approach reserves a block for a MAC address from the IEEE 802 MAC address.
  • the group address assignment is done through signaling exchange between an AP and its related (or associated) stations.
  • the stations When receiving a RTS message with a group MAC address, the stations know whether a CTS message should be sent back and when the CTS message should be sent back.
  • a group ID of the IEEE 802.1 lac PHY layer and the group MAC address may be used. That is, for each group ID defined in the 802.1 lac PHY layer, a MAC address will be assigned to group.
  • a second approach uses the group ID as a group MAC address.
  • the stations know which group the RTS message is sent to and a CTS message may sent back based on the signaling information exchanged among the stations. If there are stations with MAC addresses are the same as the group ID, then either the AP gives up the group ID or only using the traditional single RTS/CTS scheme for protection.
  • FIG 14 shows a schematic topological view of an example illustrating an AP using a group ID directly as a group MAC address, in accordance to various embodiments.
  • an API 1400 sends a RTS message 1402 with a group ID as a group MAC address.
  • the STA1 1404, the STA2 1406 and the STA3 1408 being associated with the group ID, in this case being the group MAC address, MU-MIMO downlink 1410 is established between the API 1400 and these stations 1404, 1406, 1408.
  • the STA4 1412 is located near the STA3 1408 and within an area which the RTS message can reach, the STA4 1412 being associated with a different AP2 1414 does not respond to the RTS message and no MU-MIMO is established between the STA4 1412 and the API 1400.
  • the data packet to the station may be excluded from the transmission as illustrated in Figure 15.
  • An API 1500 in Figure 5 establishes a RTS protection range 1502.
  • the STA1 1504 and the STA2 1506 receiving the RTS message each responds with a CTS message 1508, 1510.
  • the STA1 1504 further has a CTS protection range 1512 which encompasses the STA2 1506.
  • the CTS message of STA3 1514 is lost.
  • the API may exclude data transmission to the STA3 1514.
  • the ST A3 1514 may at the same time receive a message from a STA4 1518, which is located outside the protected area and the message may be for a different AP2 1520, thus collision may occur in transmission 1522.
  • a method for controlling a communication device in a network comprises generating a message for sending to each of a plurality of communication devices in the network 1602, wherein the message comprises a Media Access Control address associated with the plurality of communication devices; and sending the message to each of the plurality of communication devices 1604.
  • the generating the message 1602 may comprise generating a message indicating readiness to send data to each of the plurality of communication devices in the network.
  • the sending the message 1604 may comprise transmitting the message according to a communication protocol according to which the plurality of communication devices transmit respective response messages in response to the message, wherein each of the response messages indicates that the respective communication device of the plurality of communication devices is ready to receive the data.
  • the response messages may be sent by the plurality of communication devices simultaneously.
  • a communication device for a network comprises a receiver 1702 configured to receive a message comprising a Media Access Control address associated with a plurality of communication devices in the network; a determining unit 1704 configured to determine whether the communication device 1700 is part of the plurality of communication devices; and a processor 1706 configured to process the message as a message addressed to the communication device 1700 if it is determined that the communication device 1700 is part of the plurality of communication devices.
  • the phrase "the communication device is part of the plurality of communication devices" may refer to the communication device 1700 having an address which is associated with, or corresponds to, or is the same as the address of the plurality of communication devices.
  • the determining unit 1704 may determine collision if the message is a Request- to- Send message with a transmitter address being the same as the Media Access Control address associated with the plurality of communication devices, wherein the Request-to-Send message is sent by any communication device that is not associated with the Media Access Control address, or if the message is a Clear-to-Send message sent by one of the plurality of communication devices associated with the Media Access Control address, wherein the Clear-to-Send message being sent is not in response to a Request-to-Send message sent by a communication device associated with the Media Access Control address.
  • the communication device 1700 may further comprise a message generating circuit 1800 configured to generate a message for sending to each of the plurality of communication devices in the network, wherein in response to determining collision, the message comprises a different Media Access Control address associated with the plurality of communication devices.
  • a method for controlling a communication device in a network is provided as shown in Figure 19.
  • the method 1900 comprises receiving a message comprising a Media Access Control address associated with a plurality of communication devices in the network 1902, determining whether the communication device is part of the plurality of communication devices 1904, and processing the message as a message addressed to the communication device if it is determined that the communication device is part of the plurality of communication devices 1906.
  • the method 1900 may further comprise determining collision if the message is a Request-to-Send message with a transmitter address being the same as a Media Access Control address associated with a plurality of communication devices, wherein the Request-to-Send message is sent by any communication device that is not associated with the Media Access Control address, or if the message is a Clear-to- Send message sent by one of the plurality of communication devices associated with the Media Access Control address, wherein the Clear-to-Send message being sent is not in response to a Request-to-Send message sent by a communication device associated with the Media Access Control address.
  • the method may further comprise generating a message for sending to each of the plurality of communication devices in the network in response to determining collision, wherein the message comprises a different Media Access Control address associated with the plurality of communication devices.
  • the term "about” or “approximately” as applied to a numeric value encompasses the exact value and a variance of +/- 5% of the value.
  • the phrase "at least substantially” may include “exactly” and a variance of +/- 5% thereof.
  • the phrase "A is at least substantially the same as B” may encompass embodiments where A is exactly the same as B, or where A may be within a variance of +/- 5%, for example of a value, of B, or vice versa.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention porte sur un dispositif de communication pour un réseau, le dispositif de communication comprenant un circuit de génération de messages configuré pour générer un message destiné à être envoyé à chaque dispositif de communication parmi une pluralité de dispositifs de communication dans le réseau, le message comprenant une adresse de commande d'accès au support associée à la pluralité de dispositifs de communication, et un émetteur configuré pour envoyer le message à chacun de la pluralité de dispositifs de communication. La présente invention porte également sur un dispositif de communication pour un réseau, le dispositif de communication comprenant un récepteur configuré pour recevoir un message comprenant une adresse de commande d'accès au support associée à une pluralité de dispositifs de communication dans le réseau, une unité de détermination configurée pour déterminer si le dispositif de communication fait ou non partie de la pluralité de dispositifs de communication, et un processeur configuré pour traiter le message en tant que message adressé au dispositif de communication, s'il est déterminé que le dispositif de communication fait partie de la pluralité de dispositifs de communication. La présente invention porte également sur des procédés de commande d'un dispositif de communication.
PCT/SG2011/000390 2010-11-02 2011-11-02 Dispositifs de communication dans un réseau et procédé de commande d'un dispositif de communication WO2012060781A1 (fr)

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WO2014206283A1 (fr) * 2013-06-25 2014-12-31 Huawei Technologies Co., Ltd. Système et procédé de détection et de résolution de conflits
CN108650715A (zh) * 2012-06-19 2018-10-12 韩国电子通信研究院 无线局域网系统的基于时隙的信道接入控制装置和方法

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CN108650715A (zh) * 2012-06-19 2018-10-12 韩国电子通信研究院 无线局域网系统的基于时隙的信道接入控制装置和方法
WO2014206283A1 (fr) * 2013-06-25 2014-12-31 Huawei Technologies Co., Ltd. Système et procédé de détection et de résolution de conflits
CN105144641A (zh) * 2013-06-25 2015-12-09 华为技术有限公司 用于检测并解决冲突的系统和方法
US9433016B2 (en) 2013-06-25 2016-08-30 Futurewei Technologies, Inc. System and method for detecting and resolving conflicts
JP2016533058A (ja) * 2013-06-25 2016-10-20 ホアウェイ・テクノロジーズ・カンパニー・リミテッド コンフリクトを検出し、解決するためのシステム及び方法
US9681467B2 (en) 2013-06-25 2017-06-13 Futurewei Technologies, Inc. System and method for detecting and resolving conflicts

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