WO2016191985A1 - Procédé et dispositif de transmission de données redondantes sur une pluralité de liaisons sans fil - Google Patents

Procédé et dispositif de transmission de données redondantes sur une pluralité de liaisons sans fil Download PDF

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Publication number
WO2016191985A1
WO2016191985A1 PCT/CN2015/080415 CN2015080415W WO2016191985A1 WO 2016191985 A1 WO2016191985 A1 WO 2016191985A1 CN 2015080415 W CN2015080415 W CN 2015080415W WO 2016191985 A1 WO2016191985 A1 WO 2016191985A1
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WO
WIPO (PCT)
Prior art keywords
sender
wireless links
multiple wireless
client
packet
Prior art date
Application number
PCT/CN2015/080415
Other languages
English (en)
Inventor
Mattias Lampe
Jie Zhang
Original Assignee
Siemens Aktiengesellschaft
FENG, Da Wei
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft, FENG, Da Wei filed Critical Siemens Aktiengesellschaft
Priority to PCT/CN2015/080415 priority Critical patent/WO2016191985A1/fr
Publication of WO2016191985A1 publication Critical patent/WO2016191985A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1812—Hybrid protocols; Hybrid automatic repeat request [HARQ]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L2001/0092—Error control systems characterised by the topology of the transmission link
    • H04L2001/0096—Channel splitting in point-to-point links
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L2001/0092—Error control systems characterised by the topology of the transmission link
    • H04L2001/0097—Relays

Definitions

  • the invention relates to wireless data transmission, and more particularly to a method and device for redundant data transmission over multiple wireless links.
  • Link redundancy i.e. transmission of identical data on several independent communication links in parallel, is a well-known method to increase the end-to-end reliability and availability of a communication channel.
  • the PRP protocol “Parallel Redundancy Protocol” as specified in IEC 62439-3) is one example for a layer 2 protocol that can be applied in Ethernet networks to provide increased robustness against disturbances and component failure.
  • redundant radio links will not only increase the robustness against interference, jamming and other channel impairments but it can also eliminate data outage during the roaming phase of a mobile client and thereby allow a virtually lossless handover between different Access Points (APs) .
  • APs Access Points
  • redundant versions of a particular data packet will normally not occur on the air interfaces at exactly the same time but with some random time offset, depending on the channel conditions and other factors (e.g. random packet loss) .
  • the wireless links lead to different and time-variant delays between the redundant versions of the data packet. It is also important to keep in mind that the relative delay changes over time and therefore the link with the largest delay a one time may eventually have the smallest delay at a later time, e.g. if the quality of the radio channel improves.
  • an object of the present invention is to reduce the relative delay between the redundant wireless links.
  • the present invention provides a method for redundant data transmission over multiple wireless links, the method comprising:
  • the present invention provides a device for redundant data transmission over multiple wireless links, the device comprising:
  • a checking module configured to check whether a packet to be transmitted has been successfully transmitted over one of the multiple wireless links
  • a discarding module configured to discard the packet if the checking result is positive.
  • FIG. 1 depicts an exemplary setup of a wireless system in accordance with the invention
  • FIG. 2 depicts an exemplary flow chart for redundant data transmission over the multiple wireless links as shown in FIG. 1;
  • FIG. 3 shows a typical architecture of a multi-radio WLAN device for implementating the redundant data transmission in accordance with the present invention
  • FIG. 4 depicts another exemplary setup of a wireless system in accordance with the present invention.
  • FIG. 5 depicts another exemplary flow chart for redundant data transmission over the multiple wireless links as shown in FIG. 4;
  • FIG. 6 depicts another exemplary setup of a wireless system in accordance with the present invention.
  • FIG. 7 depicts an exampleray block diagram of a device in accordance with the present invention.
  • FIG. 8 depicts an exampleray block diagram of an apparatus in accordance with the present invention.
  • FIG. 1 depicts an exemplary setup of a wireless system 100, e.g. a WLAN system based on IEEE802.11 standards, in accordance with the present invention.
  • the system 100 comprises multiple APs 101a to 101d, an application device 106, e.g. a server, and one ore more Ethernet switches 104 which connects the APs to the application device.
  • Another application device 103 e.g. a user terminal, communicates with the application device 106 via the wireless access of a client 101 to the AP 102b.
  • the client 101 maintains multiple redundant wireless links 121a and 121b to the AP 102b at a time, thus the reliability of the wireless acess is increased.
  • a redundancy layer 115/116 replicates data packets generated by the application device 103/106 across all radio interfaces 111 and 113/112 and 114, and in receive direction eliminates duplicate packets (packets received redundantly on more than one radio interface) to be forwarded to the application device 103/106.
  • the redundancy layer 115/116 typically adds a specific protocol header to the transmitted packets, including a sequence number.
  • the redundant wirelss links 121a and 121b will use different frequency channels.
  • the client 101 leaves the coverage of the current AP 102b all redundant links will need to be transferred to another AP.
  • FIG. 2 depicts an exemplary flow chart for redundant data transmission according to the present invention over the multiple wireless links as shown in FIG. 1.
  • the method of FIG. 2 comprises the following steps:
  • step 201 the client 101 or the AP 102b, whichever as a sender, checks whether a packet to be transmitted has been successfully transmitted over one of the multiple wireless links 121a and 121b;
  • step 202 the sender discards the packet if the checking result of step 201 is positive.
  • FIG. 3 shows a typical architecture of a multi-radio WLAN device 300 for implementating the redundant data transmission in accordance with the present invention.
  • the WLAN device 300 can be either the client 101 or the AP 102b as shown in FIG. 1.
  • WLAN adapters 321a and 321b are presented by the WLAN device drivers 311 and 313 to the redundancy layer 315 as separate radio interfaces, whereas the redundancy layer 315 appears to the operating system 317 and the application 319 as a single virtual network interface.
  • the hardware of the radio interfaces can differ, in which case they may have different device drivers. More commonly, though, the radio interfaces are identical and controlled by separate logical entities within the same device driver.
  • the WLAN device 300 also has an Ethernet interface 320 and the corresponding Ethernet device driver 310, which are shown only for completeness and not in the scope of the present invention.
  • Checking whether the packet has been successfully transmitted over one of the multiple wireless links can be achieved by establishing an information exchange between the WLAN device drivers controlling the WLAN adapters. As shown in FIG. 3, the WLAN device drivers 311 and 313 are notified (e.g. by interrupt created by the WLAN adapters 321a and 321b) that a packet has been successfully transmitted (i.e. the packet has been acknowledged by the receiver) . Moreover, the redundancy layer 315 has added an identifier (usually a sequence number) to each packet which can identify sets of redundant packets (e.g. redundant packets all have the same sequence number) .
  • an identifier usually a sequence number
  • the WLAN device driver of a particular WLAN adapter Once the WLAN device driver of a particular WLAN adapter is notified of the successful delivery of a packet, it will communicate the sequence number (or a comparable identifier common to all redundant copies of the packet) to the device drivers of the other WLAN adapters.
  • a WLAN device driver Before a WLAN device driver hands over a packet from the redundancy layer to the WLAN adapter, it checks whether the sequence number (or comparable identifier) of the packet matches a sequence number previously reported by the other device drivers as a successful transmission. If so, the packet will be discarded and not forwarded to the WLAN adapter.
  • a device driver that has already handed a packet to the WLAN adapter may try to remove the packet from the queue if meanwhile the successful transmission of the same packet (e.g. identical sequence number) on another radio interface has been reported.
  • the information exchange between the WLAN device driver entities can be achieved by maintaining a single shared data structure within the driver recording sequence numbers of successfully transmitted packets, i.e. if the driver successfully completes transmission on any one radio interface, it enters the sequence number (and optionally additional information, e.g. a timestamp) into a global data structure, and whenever the driver intends to hand a packet to any of the radio interfaces, it first checks that data structure for previous successful transmissions on the other interfaces.
  • each of the device drivers may access a joint data structure stored in a shared memory to exchange information of successfully transmitted packets.
  • each of the device drivers may maintain a separate data structure in which it records sequence numbers of packets successfully transmitted by the other drivers using common techniques of inter-process-communication, such as FIFOs, pipes, sockets, shared memory, etc.
  • FIG. 4 depicts another exemplary setup of a wireless system 400 in accordance with the present invention.
  • the radio interfaces 111 and 113 of the client 101 can in this system be associated to different APs 102c and 102d.
  • a so-called “Redundancy Box” (RedBox) 108 which can be either a dedicated hardware or a software component running on the application device 106 with multiple Ethernet interfaces, takes over the functionality of the redundancy layer on the infrastructure side.
  • the system 400 therefore avoids the data outage typically encountered in WLAN networks during handover and has the additional benefit of allowing a virtually lossless roaming of the client 101.
  • the system 400 as shown in FIG. 4 can achieve the correct delivery of the redundant data packets through the Ethernet backbone by means of maintaining a separate virtual network (VLAN) for each redundant link 121a and 121b.
  • VLAN virtual network
  • this setup requires an additional information communication 122 to inform the involved APs 102c and 102d of the successful packet transmission.
  • the involved APs 102c and 102d can maintain a list of the multiple APs currently involved in the redundant data transmission.
  • FIG. 5 is another exemplary flow chart for redundant data transmission according to the present invention over the multiple wireless links as shown in FIG. 4.
  • the method of FIG. 5 comprises the following steps:
  • each o f the APs 102c and 102d maintains a list of the multiple APs involved in the redundant data transmission;
  • step 502 the AP 102b or 102c, whichever as a sender, checks whether a packet to be transmitted has been successfully transmitted over the wireless link of the other AP based on the list maintained in step 501;
  • step 503 the sender discards the packet if the checking result of step 502 is positive.
  • the AP Upon association of a client’s radio interface to an AP, the AP will inform all the other APs about this association and an ID (e.g. MAC ID plus an additional identifier obtained during or after the association phase) of the associated radio interface.
  • an ID e.g. MAC ID plus an additional identifier obtained during or after the association phase
  • the ID of the client’s radio interface should be defined in such a way that it’s able to indicate which APs are involved in the redundant links.
  • the other APs receiving a notification from the AP about the association (or de-association, respectively) of a client’s radio interface to the AP, will start (or stop, respectively) informing the AP via the communication connection 122 about successful packet transmissions over the redundant links.
  • the client upon association of a client’s radio interface with an AP the client will inform that AP about the other APs that the other client’s radio interfaces participating in the redundant data transmission are currently associated with.
  • the APs involved in the redundant data transmission will thereafter inform each other via the communication connection 122 about its successful packet transmissions.
  • the involved APs can further notify each other about the de-association of the client’s radio interface and stop the information communication 122 accordingly.
  • the redundancy layer is moved to the RedBox 108 and does not exist in the APs, which in this case may even be single-radio devices.
  • the respective WLAN device driver of the APs 102c and 102d can share the information of successfully transmitted packets via the communication connection 122.
  • radio links use an automatic repeat request mechanism (ARQ) with retransmission of lost packets;
  • ARQ automatic repeat request mechanism
  • radio access scheme employs a listen-before-talk concept, i.e. transmission of a packet will have to wait until the radio channel is free.
  • FIG. 7 depicts an exampleray block diagram of the device in accordance with the present invention.
  • the device 700 as shown in FIG. 7 can be implemented as software, hardware (e.g. DSP, FPGA or ASIC, etc) or their combination.
  • the device 700 comprises:
  • a checking module 702 configured to check whether a packet to be transmitted has been successfully transmitted over one of the multiple wireless links
  • a discarding module 703 configured to discard the packet if the checking result is positive.
  • the multiple wireless links belong to a single device, such as the client 101 or the AP 102b as described above.
  • the multiple wireless links belong to multiple devices, such as the APs 102c and 102d as decribed above.
  • the checking module 702 in such embodiment is configured to check whether the packet has been successfully transmitted over one of the multiple wireless links of another device of the multiple devices.
  • the device 700 as shown in FIG. 7 further comprises:
  • a maintaining module 701 configured to maintain a list of the multiple devices involved on the wireless links.
  • the maintaining module 701 can maintain the list by information from the another device upon association of a client to the another device over one of the multiple wireless links.
  • the maintaining module 701 can maintain the list by information from a client upon association of the client to the device 700.
  • the client is in this situation associated both to the device and the another device at a time over the multiple wireless links.
  • the device 700 is also informed by the another device for the maintaining module 701 to update the list upon de-association of the client to the another device.
  • FIG. 8 depicts an exampleray block diagram of an apparatus for redundant data transmission over multiple wireless links in accordance with the present invention.
  • the apparatus 800 comprises:
  • memory 801 configured to store instructions
  • a processor 802 configured to excute the instructions to perform the operations of the device 700 above.
  • the present invention also provides a computer-readable medium storing instructions, which when excuted by a processor performs operations of the device 700 above.

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

Abstract

L'invention concerne un procédé et un dispositif de transmission de données redondantes sur une pluralité de liaisons sans fil. Dans le procédé : un expéditeur vérifie si un paquet devant être transmis par l'expéditeur a été transmis avec succès sur une de la pluralité de liaisons sans fil ; dans l'affirmative, l'expéditeur abandonne le paquet. En évitant la transmission inutile de paquets redondants qui ont déjà été transmis avec succès sur une des liaisons sans fil, l'invention réduit le retard relatif entre les paquets redondants. Le temps de basculement est alors réduit et l'usage des ressources radio amélioré.
PCT/CN2015/080415 2015-05-29 2015-05-29 Procédé et dispositif de transmission de données redondantes sur une pluralité de liaisons sans fil WO2016191985A1 (fr)

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PCT/CN2015/080415 WO2016191985A1 (fr) 2015-05-29 2015-05-29 Procédé et dispositif de transmission de données redondantes sur une pluralité de liaisons sans fil

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Application Number Priority Date Filing Date Title
PCT/CN2015/080415 WO2016191985A1 (fr) 2015-05-29 2015-05-29 Procédé et dispositif de transmission de données redondantes sur une pluralité de liaisons sans fil

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3416322A1 (fr) * 2017-06-14 2018-12-19 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Communications fiables à ultra faible latence
US10237784B2 (en) * 2017-03-24 2019-03-19 Motorola Mobility Llc Split bearer packet data converge protocol protocol data unit routing
CN111818231A (zh) * 2020-07-06 2020-10-23 全时云商务服务股份有限公司 丢包补偿方法、装置、数据报文传输系统和存储介质
CN113411823A (zh) * 2020-03-17 2021-09-17 青岛海尔工业智能研究院有限公司 一种无线通信系统及方法
US11405948B2 (en) 2017-06-14 2022-08-02 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Joint resource pools for uplink communications

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EP2048637A2 (fr) * 2007-10-08 2009-04-15 Honeywell International Inc. Réseaux sans fil pour applications très fiables
CN102208962A (zh) * 2011-05-19 2011-10-05 清华大学 无线数据传输方法
CN103780365A (zh) * 2014-01-26 2014-05-07 中国神华能源股份有限公司 动态的多链路冗余数据传输方法和系统

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2048637A2 (fr) * 2007-10-08 2009-04-15 Honeywell International Inc. Réseaux sans fil pour applications très fiables
CN102208962A (zh) * 2011-05-19 2011-10-05 清华大学 无线数据传输方法
CN103780365A (zh) * 2014-01-26 2014-05-07 中国神华能源股份有限公司 动态的多链路冗余数据传输方法和系统

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10237784B2 (en) * 2017-03-24 2019-03-19 Motorola Mobility Llc Split bearer packet data converge protocol protocol data unit routing
US10813005B2 (en) 2017-03-24 2020-10-20 Motorola Mobility Llc Split bearer packet data converge protocol protocol data unit routing
US11700548B2 (en) 2017-03-24 2023-07-11 Motorola Mobility Llc Split bearer packet data converge protocol protocol data unit routing
EP3416322A1 (fr) * 2017-06-14 2018-12-19 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Communications fiables à ultra faible latence
US11387946B2 (en) 2017-06-14 2022-07-12 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Reliable ultra-low latency communications
US11405948B2 (en) 2017-06-14 2022-08-02 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Joint resource pools for uplink communications
CN113411823A (zh) * 2020-03-17 2021-09-17 青岛海尔工业智能研究院有限公司 一种无线通信系统及方法
CN113411823B (zh) * 2020-03-17 2023-02-03 卡奥斯工业智能研究院(青岛)有限公司 一种无线通信系统及方法
CN111818231A (zh) * 2020-07-06 2020-10-23 全时云商务服务股份有限公司 丢包补偿方法、装置、数据报文传输系统和存储介质
CN111818231B (zh) * 2020-07-06 2021-02-09 全时云商务服务股份有限公司 丢包补偿方法、装置、数据报文传输系统和存储介质

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