EP1055341A1 - Reseaux mailles hertziens - Google Patents

Reseaux mailles hertziens

Info

Publication number
EP1055341A1
EP1055341A1 EP98962652A EP98962652A EP1055341A1 EP 1055341 A1 EP1055341 A1 EP 1055341A1 EP 98962652 A EP98962652 A EP 98962652A EP 98962652 A EP98962652 A EP 98962652A EP 1055341 A1 EP1055341 A1 EP 1055341A1
Authority
EP
European Patent Office
Prior art keywords
wireless network
sites
protection
working
path
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP98962652A
Other languages
German (de)
English (en)
Inventor
Rony Levy
Paz Gilboa
Tuvia Barak
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Radiotel Ltd
Original Assignee
Radiotel Ltd
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 Radiotel Ltd filed Critical Radiotel Ltd
Publication of EP1055341A1 publication Critical patent/EP1055341A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/22—Alternate routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/28—Routing or path finding of packets in data switching networks using route fault recovery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/40169—Flexible bus arrangements
    • H04L12/40176—Flexible bus arrangements involving redundancy
    • H04L12/40182—Flexible bus arrangements involving redundancy by using a plurality of communication lines
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/42—Loop networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/42—Loop networks
    • H04L12/427—Loop networks with decentralised control

Definitions

  • This invention refers to managed survivable wireless networks, viz. wireless networks that are capable of operating even after failures have occurred in links between their stations.
  • the networks of the invention also provide a high efficiency and quality of service under variable operating conditions.
  • Network survivability viz. the capability of a network to continue operating in spite of a failure or near-failure, such as a substantial drop in transmission quality, in one or more of the links comprised in the network
  • SONET Synchronous Optical Networks
  • SDH Synchronous Digital Hierarchy
  • the most common configuration in a multi-point fixed radio environment is a logical Star configuration, which typically comprises a main Hub and a plurality of Remote Terminals (RT) or Sites, as they will generally be called hereinafter.
  • the main Hub which includes a Central control Office (CO), which in turn contains the main switch, is composed of an array of transmitters and an array of receivers.
  • the RTs or Sites are equipped with a single transmitter and a single receiver.
  • the main Hub is directly connected to each RT by a link or channel - hereinafter "working" or "main” link.
  • a link or channel (these two terms should be considered herein as synonymous, is defined by a frequency or a very narrow band of frequencies, which means that each RT or Site is characterized by the frequency or narrow band assigned to it, whereas the main Hub can transmit and receive over all the frequencies of a very wide band.
  • the corresponding RT ceases to be operative.
  • B-ISDN Broadband Integrated Services Digital Network
  • GSM Groupe Special Mobile
  • the invention provides a wireless network which comprises:
  • I - a Hub comprising a transmitter array and a receiver array
  • the network comprises means for switching traffic from one to another of said communication paths or routes.
  • path indicates the route by which a signal travels between the point at which it has been sent and the point at which it has been received.
  • a path may be constituted by a single link or channel, viz. be a direct path between a transmitter and a receiver, or by a succession of links or channels which convey the signal from the transmitter to the receiver though one or more intermediate nodes, each of which receives the signal and retransmits it, the reception and transmission channels being generally different.
  • the network according to the invention comprises:
  • the means for switching traffic from one another of the communication paths comprise means for switching traffic a) from a path defined by a working link to a path defined by the combination of another working link with at least one protection link, or defined by a plurality of protection links, or b) from a path defined by the combination of a working link with at least one protection link to a path defined by another such combination, or defined by a plurality of protection links.
  • traffic is meant herein the transmission of signals or information of any kind.
  • the said means for switching traffic operate automatically in case of failure of a link comprised in a communication path.
  • the wireless network is a ring network comprising a plurality of Sites successively connected to one another by a plurality of links each connecting to Sites. Any one of the Sites can be considered a Hub and the remaining Sites can be considered RTs.
  • said protection links carry extra traffic, which are lost when the main traffic is switched to a path comprising said link.
  • an ISDN link can be provided between the Hub and one of the Sites in any network or communication system as hereinbefore defined.
  • ISDN terminals can be provided at one or more Sites, to provide access of ISDN information into the network.
  • the invention also comprises a communication system, which comprises a plurality of networks, each as hereinbefore defined, and means for interconnecting the same. More preferably, means are also provided for using the extra capacity of at least one such network in case of crisis in the Hub of at least another such network. Further, one or more of such networks can be integrated into a broader communication system, such as GSM.
  • the invention further comprises a method of operating a survivable wireless network as hereinbefore defined, which comprises sending information over both working and protection paths and selecting at each Site for the best available path.
  • said method comprises sending the main information over the working path, using the protection path to carry extras traffic, and selecting at each Site the best available path, and in case of failure, sending the main information over the protected path, while losing the extra traffic.
  • the wireless network is a ring network and is operated by sending information constantly in the two opposite directions and selecting at each Site the path that is best at the moment the information is received. More preferably, information is sent by the full bandwidth of the system and the relevant information is dropped at each Site.
  • FIG. 1 schematically illustrates a Multipoint Meshed Survivable Network, which, by way of illustration only, is represented as comprising 5 nodes: a Hub and 4 RTs;
  • FIG. 2 schematically illustrates a point-to-multipoint Survivable Ring Network
  • FIG. 3 schematically illustrates a point-to-multipoint Survivable ISDN Network
  • - Fig. 4 is a simplified GSM structure diagram
  • - Figs. 5(a), 5(b), 5(c), 5(d), 5(e) schematically illustrate different network architectures for the GSM
  • FIG. 6 schematically illustrates two combined Survivable Networks, each comprising a Base Station Controller (BSC) which controls a plurality (three in the drawing) of Base Transceiver Stations (BTS).
  • BSC Base Station Controller
  • BTS Base Transceiver Stations
  • Fig. 1 schematically illustrates a first embodiment of the invention, which is a Multipoint Meshed Survivable Network.
  • Numeral 10 indicates the Hub, which includes a symbolically represented Network Management (NM) 11.
  • NM Network Management
  • Numerals 12, 13, 14 and 15 are four Sites or RTs.
  • Hub 10 is connected to the aforesaid Sites, through working links respectively indicated at 16, 17, 18 and 19.
  • protective links are provided as follows: link 20 between Sites 12 and 13; link 21 between Sites 13 and 14; and fink 22 between Sites 14 and 15.
  • the working links as well as the protection links are two-way links.
  • the said network is controlled by the NM 11 at the Hub.
  • the network's status is conveyed to the NM by Operation and Maintenance (OAM) channels from the RT Site's local controllers via the working and protection finks.
  • OAM Operation and Maintenance
  • Any one or more than one of the main or working links, 16, 17, 18 and 19, may cease to operate, or the quality of service (QOS) associated with it may become degraded.
  • QOS quality of service
  • the NM at the Hub will cause a new communication path to become operative to transmit the main information, instead of the original path defined by a failed working link.
  • the new path will be defined by the combination or succession of an efficient working link and one or more protection links.
  • the information that is to be transmitted to a first Site which can no longer be reached efficiently through the corresponding working link, because of the failure of degraded functionality of this latter, is transmitted to a second Site, preferably one of the Sites near to said first Site, via the corresponding working link, together with an instruction to said second Site to retransmit the information via a protection fink to said first Site, to which it is destined.
  • information from said first Site can be transmitted to said second Site, via the same protection fink, together with an instruction to said second Site to retransmit the information to the Hub via its working link.
  • information from said first Site can be transmitted to said second Site, via the same protection fink, together with an instruction to said second Site to retransmit the information to the Hub via its working link.
  • working link 18 should be interrupted or cease to operate efficiently, so that direct communication of information from the Hub to Site 14, and vice versa, is no longer possible
  • information can be sent by the Hub via a survival path constituted by working link 19 and a protection link, specifically, in the case illustrated, via working fink 19 to Site 15, and from Site 15, over protection link 22, to Site 14; or it can be sent via another survival path, viz. via working link 17 to Site 13, and from Site 13, over protection link 21, to Site 14.
  • the action of the NM will be manual, or preferably automatic, viz. determined by reception at the NM of a signal indicating the loss or degraded quality of signal over a working link (18, in the case exemplified), which signal will be received at the relevant Site (14, in the case exemplified), as well. Since alternative survival paths are available, the local controller at said relevant Site will select the one that gives better results. In general, information is always transmitted in both directions, clockwise and anticlockwise. The terminals accept the best and coherent signal.
  • the NM is constantly monitoring the signal and the selection is done by making sure that the signal have the best Bit Error Rate (BER), and, for coherency, in terms of weather or atmospheric conditions which are known to affect wireless signals at high RF frequencies, and therefore need different types of equalization, examples of which are "adaptive” or “blind” equalization to compensate.
  • BER Bit Error Rate
  • modulation techniques viz. QPSK, 16 QAM, 64 QAM, etc.
  • the protective fink used e.g., link 31 or 22
  • this extra traffic will be lost when the Hub decides to activate a survival path which includes said protective link in order to transmit information to a Site which could not otherwise be reached, e.g., in the aforesaid example, to Site 14.
  • the information may be continuously sent over both the working and the survival paths.
  • information to Site 14 can be sent both through working link 18 or through working link 19 and protection link 22.
  • the Site will select the path which is better in terms of noise, etc. This is permitted because the information is sent through working link 18 at a frequency and through protection path 22 at a different frequency, and therefore the two receptions can be compared and one of them selected
  • Fig. 2 illustrates another embodiment of the invention, which will be called herein "Point-to-multipoint Survivable Ring Network”. Said network, differs from that of Fig. 1 in that the Sites are arranged, so to speak, in a succession, and links are provided from the Hub only to Sites that can be called “terminal”.
  • Hub 30 having an NM 31, is connected to Site 32 and Site 35 through working links 36 and 39, respectively.
  • Protection links 40, 41 and 42 are provided.
  • Site 33 will receive information through working link 36 and protection link 40 or through working link 39 and protection links 42 and 43; and Site 34 will receive information through working link 39 and protection link 42, or through working link 36 and protection links 40 and 41.
  • each Site will select the path which provides the best information. Since there are two routes of information to each Site, if one of the Sites leaves the network, e.g., when a cellular telephone is shifted to an area which cannot be reached by Hub 30, the network does not cease to operate, because the other route is still available. Thus, even if one of the two terminal Sites, e.g., Site 32, should leave the area covered by Hub 30, the remaining Sites will still receive information from working link 39 and protection links 42, 41 and 40. Likewise, if the working link between the Hub and a terminal Site should be interrupted, that Site will still receive information through the other working link, and/or the intermediate protection finks.
  • each Site is really a Hub that has double RF units and Modems; or, in other words, a ring of a plurality of Sites is provided, comprising finks each of which connects two successive or adjacent Sites, wherein each Site can be considered as the Hub.
  • the ring is provided with means for sending the information in both directions at all times. Therefore, one cannot actually identify which path is a protection path and which is the main path.
  • the essential concept is that the same information is circulated fully in both directions and at each node the best path is selected at the time the information is received. This system will support add/drop type communication, which will allow to utilize the full bandwidth of the system, while dropping the relevant information at each node as a multiple of El/Tl.
  • Fig. 3 illustrates a third embodiment of the invention, which will be called "ISDN BRI (Basic Rate Interface) multipoint Network".
  • This provides a B- ISDN access. It includes a network such as illustrated in Fig. 1, with the addition of an ISDN link.
  • An ISDN multiplexer 52 is provided at the NM 51 of the Hub 50, and is connected by a link 53 to another ISDN multiplexer 54, which is located at one of the Sites 55, 56, 57 and 58 - in the particular example shown by way of illustration, to Site 57.
  • the aforesaid Sites are connected to the Hub 50 by working links 60 to 63 respectively, and protection links 64, 65 and 66 are provided between Sites, as in the preceding embodiments.
  • the ISDN link provides an alternative route for transmitting information, which can reach any Site through the protection links.
  • ISDN terminal equipment units 67, 68, 69 are provided at the RTs that are not connected to ISDN link 53, to permit access of ISDN information through the RTs.
  • the ISDN link provides an NT (Network Terminal) functionality, and a multiplexed voice/fax grade 3 can be carried over the ISDN link.
  • NT Network Terminal
  • the embodiment of Fig. 3 provides a Survivable Wireless ISDN Network which offers high-speed connection in a variety of quality and service grades for the shared protection capacity of the link, using the ISDN products which offer the best cost effective solution.
  • the Site which is connected to the ISDN link in this example, Site 57, can use an existing narrow band, ( 64 K, 128 K) leased fine fink, offering extra protection through the different routes which the network makes available.
  • the network of Fig. 3 can serve either as a wireless ISDN extension, or a private ISDN network which provides a gateway to the public ISDN network.
  • Fig. 4 illustrates another application of the invention, specifically, a survivable GSM network.
  • Fig. 4 is a simplified GSM structure diagram, including embodiments of the invention.
  • the Mobile Switching Center can be connected to a Public Switch Telephone Network (PSTN) or an ISDN.
  • PSTN Public Switch Telephone Network
  • the MSC in turn is connected to a plurality of Base Station Controllers (BSC), two in the case illustrated in Fig. 4.
  • BSC Base Station Controllers
  • Each BSC is connected to a number of Base Transceiver Stations (BTS) - three for each BSC, in the embodiment of Fig. 4.
  • BTS Base Transceiver Stations
  • El and Tl are standard types of bit rate communication.
  • a Management System MS which comprises message transfer terminal equipment (TE-MT).
  • TE-MT message transfer terminal equipment
  • Fig. 5 illustrates various possible architecture configurations for the GSM network.
  • the MSC is connected to a Base Station Controller (BSC) which in turn is coupled to a Base Transceiver Station (BTS).
  • BSC Base Station Controller
  • BTS Base Transceiver Station
  • FIG. 5b Another configuration, called herein “Combined Star”, is illustrated in Fig. 5b, wherein the MSC is connected to a BSC, which in turn controls a number (three in the figure) of BTSs.
  • the BSC controls a number of BTSs.
  • the BSC is directly coupled to three BTSs and controls three other BTSs through a fink.
  • the BSC directly controls the BTS and controls two more BTSs, one directly and one through the other BTS.
  • Fig. 6 schematically illustrates a simple case of a communication system which comprises a combination of networks embodying the invention - in the figure, for purposes of illustration, two networks.
  • Two BSCs indicated as 70 and 80, are provided.
  • BSC 70 controls BTSs 72, 73 and 74 through working links 76, 77 and 78, the BTSs being connected by protection links 78 and 79.
  • BTS 80 controls BTSs 81, 82 and 83 through working finks 84, 85 and 86, protection links 87 and 88 being provided between the BTSs.
  • the number of components indicated in Fig. 6 is only illustrative, and the various networks may comprise a different number of Sites or terminal stations.
  • the two networks are connected by an additional protection link 90, which connects two BTSs, in the example, BTSs 73 and 83.
  • a direct link could be provided between BSC 70 and BSC 80.
  • the function of the protection links is the same as that explained with respect, e.g., to Fig. 1, but additionally, the protection link 90 connects to the two networks, so that the system may survive in case of the failure of one of the BSCs.
  • the network associated with each of the BSCs has been illustrated as a Meshed Survivable Network, as in Fig. 1, it could be constituted by a Multipoint Survivable Ring Network, as illustrated in Fig. 2.
  • One or two of the networks could also be a Survivable ISDN Network, as illustrated in Fig. 3.

Abstract

L'invention porte sur un réseau hertzien surviable tel qu'un réseau en anneau qui comprend un concentrateur principal (10) doté d'un ensemble d'émetteurs et de récepteurs, une pluralité de sites (12, 15), chaque site comprenant un émetteur et un récepteur et aux moins deux voies de communication (16-22) permettant de transmettre des informations entre le concentrateur principal et le site. Plusieurs voies de communication sont des voies de trafic (16-19) et d'autres voies de communication fonctionnent comme des voies de protection (20-22) dotées de système de commutation permettant de passer d'une voie de communication à une autre. Chaque voie de communication comprend au moins une liaison hertzienne bidirectionnelle. Le réseau comprend également des liaisons de trafic (16-19) situées entre le concentrateur (10) et au moins deux des sites (12-15), et des liaisons de protection (20-22) raccordant un nombre de sites entre eux. Le système commutant le trafic d'une voie de communication à une autre comprend un dispositif commutant le trafic d'une voie définie par une liaison de trafic à une voie définie par la combinaison d'une autre liaison de trafic avec au moins une liaison de protection, ou définie par une pluralité de liaisons de protection, ou bien ce dispositif permet de commuter le trafic d'une voie définie par la combinaison d'une liaison de trafic avec au moins une liaison de protection à une voie définie par une autre combinaison, ou définie par une pluralité de liaisons de protection.
EP98962652A 1998-01-05 1998-12-31 Reseaux mailles hertziens Withdrawn EP1055341A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IL12285298A IL122852A (en) 1998-01-05 1998-01-05 Meshed wireless networks
IL12285298 1998-01-05
PCT/IL1998/000636 WO1999035868A1 (fr) 1998-01-05 1998-12-31 Reseaux mailles hertziens

Publications (1)

Publication Number Publication Date
EP1055341A1 true EP1055341A1 (fr) 2000-11-29

Family

ID=11071057

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98962652A Withdrawn EP1055341A1 (fr) 1998-01-05 1998-12-31 Reseaux mailles hertziens

Country Status (5)

Country Link
EP (1) EP1055341A1 (fr)
AU (1) AU1780399A (fr)
IL (1) IL122852A (fr)
NO (1) NO20003421L (fr)
WO (1) WO1999035868A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030021251A1 (en) * 2001-07-30 2003-01-30 Ramin Moshiri-Tafreshi Self-healing wireless communication systems
JP3972737B2 (ja) * 2002-06-05 2007-09-05 日本電気株式会社 ディジタル伝送システム及びそれに用いるディジタル伝送方法
US6879574B2 (en) * 2002-06-24 2005-04-12 Nokia Corporation Mobile mesh Ad-Hoc networking

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1250515B (it) * 1991-10-07 1995-04-08 Sixtel Spa Rete per area locale senza fili.
US5276703A (en) * 1992-01-13 1994-01-04 Windata, Inc. Wireless local area network communications system
GB2292868B (en) * 1994-08-26 1998-08-05 Nec Corp Cordless telephone system
FI100081B (fi) * 1995-02-20 1997-09-15 Nokia Telecommunications Oy Henkilökohtainen tietoliikennejärjestelmä
JPH0951573A (ja) * 1995-08-03 1997-02-18 Iwatsu Electric Co Ltd 基地局多重化方法と装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9935868A1 *

Also Published As

Publication number Publication date
NO20003421L (no) 2000-08-28
WO1999035868A1 (fr) 1999-07-15
NO20003421D0 (no) 2000-06-30
IL122852A0 (en) 1999-03-12
IL122852A (en) 2001-10-31
AU1780399A (en) 1999-07-26

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