WO2003056731A1 - Procedes de synchronisation pour systeme de communications - Google Patents

Procedes de synchronisation pour systeme de communications Download PDF

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Publication number
WO2003056731A1
WO2003056731A1 PCT/GB2003/000007 GB0300007W WO03056731A1 WO 2003056731 A1 WO2003056731 A1 WO 2003056731A1 GB 0300007 W GB0300007 W GB 0300007W WO 03056731 A1 WO03056731 A1 WO 03056731A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
nodes
noise ratio
schedule
target
Prior art date
Application number
PCT/GB2003/000007
Other languages
English (en)
Inventor
Anthony Peter Hulbert
Original Assignee
Roke Manor Research Limited
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 Roke Manor Research Limited filed Critical Roke Manor Research Limited
Publication of WO2003056731A1 publication Critical patent/WO2003056731A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0602—Systems characterised by the synchronising information used

Definitions

  • This invention relates to synchronisation methods for a communications system for synchronising the operation of base stations.
  • a Global Positioning System GPS receiver is included in the node which receives the accurate timing signals used in the GPS system.
  • Nodes equipped with the timing means transmit a timing signal to other nodes and they adjust their timing accordingly in a master slave arrangement. The timing message is relayed to more remote nodes that cannot receive the timing message directly from the master node in a chain of hops.
  • the present invention arose from a realisation by the inventor that the radio resource allocated for synchronisation of the UE may be also utilised for the synchronisation of the network.
  • a method of synchronising a network comprising allocating a first radio resource for synchronising mobile nodes to network nodes and utilising the first radio resource for synchronising the network nodes.
  • the first radio resource is a downlink pilot timeslot.
  • the synchronisation of the network nodes across a network takes place in accordance with a schedule.
  • the schedule is preferably based on a required signal to
  • the signal to noise ratio is chosen to be that which all the network nodes can achieve. This is determined by a routine which varies a target signal to noise ratio until not all the network nodes can achieve the target. Then the last target value is used as the signal to noise ratio to be used.
  • FIG. 1 shows in schematic form a communications network operating in accordance with the invention.
  • FIG. 1 is an explanatory diagram showing the steps in the method.
  • a UMTS third generation mobile communications network 1 includes network nodes 2 to 9 and user equipment 10 and 11.
  • the network nodes 2 to 9 are node Bs serving geographically separate cells.
  • Certain of the node Bs 2 and 6 include Global Positioning System GPS receivers which derive time from signals received from satellites (not shown).
  • the node Bs including the GPS receivers are termed master nodes and they will be used to send timing synchronisation signals to the other node Bs in a manner which will now be described.
  • a flag denoting the available SINR being exceeded is cleared.
  • a target signal to noise ratio is set to an initial target value.
  • step 23 all master nodes are designated as potential "sources”. All the other nodes are then designated as potential destinations in step 24 and the schedule count set to 1 in step 25.
  • the next step 26 is to then determine for each destination node a best (maximum path gain) source. If there are any sources which are not the best source for any of the destinations then they are removed from the set of sources in step 27. An optional power control step 28 will be described later.
  • the signal to noise ratio is computed for each destination node based on the respective best sources.
  • a decision step 30 determines if all the signal to noise ratios are less than the target. If they are the yes branch is followed and the next step is step 31.
  • step 31 the destination with the lowest signal to noise ratio and below a target threshold is identified and removed from the set of destinations for the current schedule. (If this was the only destination for its source then the source is also removed from the set for this schedule in step 32.)
  • An optional power control step is carried out at step 33 and the signal to noise ratios for the remaining destinations are then re-computed in step 34.
  • the yes branch then loops back to step 30.
  • the process is repeated by removing the destination having the lowest signal to noise ratio and re-calculating the signal to noise ratios for the remaining destinations until the lowest and hence all of the destinations meet the target.
  • the assignment part of the process for the first schedule is then complete by the no branch being followed form step 30 to decision step 35. If all the nodes are assigned then the available signal to noise ratio flag is set in step 36 and the process finishes.
  • Step 37 compares the schedule count with a pre-set value for the maximum number of schedules to be carried out. If the count equals the precept maximum then the yes branch is followed to step 36. If not then the next transmission schedule is completed in the same way as the first but with this time the sources being the set of destinations of the first schedule by step 38. The destinations are then set as the remainder in step 39. The schedule count is then incremented in step 40 and the process returns to step 26. Thus, subsequent schedules are derived in the same manner upto a predetermined number. If any node Bs remain at the end of this process without a schedule for synchronisation then the process is repeated using a lower target for the signal to noise ratio and so on until the process is successful.
  • Step 41 determines is all the nodes are assigned. If they are, then in step 42 the signal to noise ratio target is increased and the process returns to step 23. If they are not then the available signal to noise ratio exceeded flag is set in step 43 and in a next step 44 the target signal to noise ratio is reduced. The process then returns to step 23.
  • the synchronisation burst is then transmitted in accordance with the derived schedule on a downlink pilot timeslot DwPTS in the downlink pilot channel DwPCH. This is the channel allocated for use to synchronise the user equipment to the nodeB.
  • the optional power control steps 28, 33 are implemented and the power level is adjusted to ensure that for each source the target signal to noise ratio is met for the synchronisation signal transmitted to each of the destinations.

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

Abstract

Dans un premier procédé, des signaux de synchronisation sont transmis dans une ressource de communications attribuée pour un autre usage. Le second procédé consiste à dériver un programme à suivre pour la transmission de signaux de synchronisation à travers un réseau.
PCT/GB2003/000007 2002-01-04 2003-01-03 Procedes de synchronisation pour systeme de communications WO2003056731A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0200091.7 2002-01-04
GB0200091A GB0200091D0 (en) 2002-01-04 2002-01-04 Scheduling algorithm for nodeb steady state sync

Publications (1)

Publication Number Publication Date
WO2003056731A1 true WO2003056731A1 (fr) 2003-07-10

Family

ID=9928586

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2003/000007 WO2003056731A1 (fr) 2002-01-04 2003-01-03 Procedes de synchronisation pour systeme de communications

Country Status (2)

Country Link
GB (1) GB0200091D0 (fr)
WO (1) WO2003056731A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000014900A1 (fr) * 1998-09-10 2000-03-16 Qualcomm Incorporated Procede et dispositif de planification distribuee optimale des ressources telles que le debit et la puissance, par la liaison inverse d'un systeme de radiocommunications
WO2001054302A1 (fr) * 2000-01-19 2001-07-26 Motorola Limited Ordonnanceur de paquets et procede associe
WO2001054299A2 (fr) * 2000-01-19 2001-07-26 Motorola Limited Programmateur de paquets et procede correspondant
WO2001072081A1 (fr) * 2000-03-23 2001-09-27 Siemens Mobile Communications S.P.A. Procedures de transfert dans un systeme de radiocommunication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000014900A1 (fr) * 1998-09-10 2000-03-16 Qualcomm Incorporated Procede et dispositif de planification distribuee optimale des ressources telles que le debit et la puissance, par la liaison inverse d'un systeme de radiocommunications
WO2001054302A1 (fr) * 2000-01-19 2001-07-26 Motorola Limited Ordonnanceur de paquets et procede associe
WO2001054299A2 (fr) * 2000-01-19 2001-07-26 Motorola Limited Programmateur de paquets et procede correspondant
WO2001072081A1 (fr) * 2000-03-23 2001-09-27 Siemens Mobile Communications S.P.A. Procedures de transfert dans un systeme de radiocommunication

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEONG YUI WONG ET AL: "Multiuser OFDM with adaptive subcarrier, bit, and power allocation", IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, OCT. 1999, IEEE, USA, vol. 17, no. 10, pages 1747 - 1758, XP002237965, ISSN: 0733-8716 *

Also Published As

Publication number Publication date
GB0200091D0 (en) 2002-02-20

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