Secondary synchronization sequences for cell group detection in a cellular communications system

US 7,961,709 B2
Filed: 12/07/2007
Issued: 06/14/2011
Est. Priority Date: 01/08/2007
Status: Active Grant

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1. A method of indicating timing parameters and an identity of a particular cell group from a number, M, of possible cell groups in a signal transmitted in a cellular communication system that employs a radio frame in a physical layer, the radio frame comprising a number of time slots, the method comprising:

transmitting, in a known one of the time slots of the radio frame, a synchronization signal, S₁, that comprises a pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a first ordering; and

transmitting, in another known one of the time slots of the radio frame, a synchronization signal, S₂, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a second ordering,wherein;

each member of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jis selected from a group comprising N_seqdifferent sequences, wherein N_seqis at least ceil

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Abstract

Timing parameters and an identity of a particular one of a number of cell groups are indicated in a signal transmitted in a cellular communication system having a radio frame in a physical layer, the radio frame comprising a number of time slots. In a known one of the time slots, a synchronization signal, S₁, is transmitted that comprises a pair of sequences arranged in a first ordering. In another known one of the time slots, a synchronization signal, S₂, is transmitted that comprises a pair of sequences arranged in a second ordering. The selected pair of sequences is uniquely identified with the particular cell group, and the first ordering of the sequences is used only for transmission in the known one of the time slots, and the second ordering of the sequences is used only for transmission in said another known one of the time slots.

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31 Claims

1. A method of indicating timing parameters and an identity of a particular cell group from a number, M, of possible cell groups in a signal transmitted in a cellular communication system that employs a radio frame in a physical layer, the radio frame comprising a number of time slots, the method comprising:
- transmitting, in a known one of the time slots of the radio frame, a synchronization signal, S₁, that comprises a pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a first ordering; and
  
  transmitting, in another known one of the time slots of the radio frame, a synchronization signal, S₂, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a second ordering,wherein;
  
  each member of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jis selected from a group comprising N_seqdifferent sequences, wherein N_seqis at least ceil
- View Dependent Claims (2, 3, 4)
- - 2. The method of claim 1, wherein:
    - the physical layer of the cellular communication system employs Orthogonal Frequency Division Multiplexing;
      
      the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jis effected by transmitting the sequence {tilde over (S)}_ion a first set of one or more sub-carriers, and transmitting the sequence {tilde over (S)}_jon a second set of one or more sub-carriers; and
      
      the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jis effected by transmitting the sequence {tilde over (S)}_jon the first set of one or more sub-carriers, and transmitting the sequence {tilde over (S)}_jon the second set of one or more sub-carriers.
  - 3. The method of claim 1, wherein:
    - in the physical layer of the cellular communication system, symbols of the synchronization signal, S₁, are separated in a frequency domain;
      
      the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jis effected by transmitting the sequence {tilde over (S)}_ion a first set of frequencies, and transmitting the sequence {tilde over (S)}_jon a second set of frequencies; and
      
      the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jis effected by transmitting the sequence {tilde over (S)}_jon the first set of frequencies, and transmitting the sequence {tilde over (S)}_ion the second set of frequencies.
  - 4. The method of claim 1, wherein the use of the first ordering of the sequences only for transmission in the known one of the time slots of the radio frame, and the use of the second ordering of the sequences only for transmission in said another known one of the time slots enables detection of radio frame timing using just one of the synchronization signals, S₁and S₂.

5. A method of detecting timing parameters and an identity of a particular cell group from a number, M, of possible cell groups in a signal received in a cellular communication system that employs a radio frame in a physical layer, the radio frame comprising a number of time slots including two time slots associated with a synchronization channel, the method comprising:
- receiving, in one of the time slots associated with the synchronization channel, one of first and second synchronization signals, S₁and S₂, wherein the first synchronization signal S₁comprises a pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a first ordering and the second synchronization signal S₂comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a second ordering;
  
  determining which of a number of predefined sequences best matches the received sequence {tilde over (S)}_i, which of the number of predefined sequences best matches the received sequence {tilde over (S)}_j, and whether the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jwere arranged in the first ordering or the second ordering, wherein the number of predefined sequences is selected from a group comprising N_seqdifferent sequences, wherein N_seqis at least ceil
- View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- - 6. The method of claim 5, wherein:
    - the physical layer of the cellular communication system employs Orthogonal Frequency Division Multiplexing;
      
      the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_ito be received on a first set of one or more sub-carriers, and the sequence {tilde over (S)}_jto be received on a second set of one or more sub-carriers; and
      
      the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_jto be received on the first set of one or more sub-carriers, and the sequence {tilde over (S)}_ito be received on the second set of one or more sub-carriers.
  - 7. The method of claim 6, wherein the first and second synchronization signals, S₁and S₂, and the sequences and {tilde over (S)}_iand {tilde over (S)}_jare all of equal length.
  - 8. The method of claim 5, wherein:
    - in the physical layer of the cellular communication system, symbols of the synchronization signal, S₁, are separated in a frequency domain;
      
      the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_ito be received on a first set of frequencies, and the sequence {tilde over (S)}_jto be received on a second set of frequencies; and
      
      the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_jto be received on the first set of frequencies, and the sequence {tilde over (S)}_ito be received on the second set of frequencies.
  - 9. The method of claim 5, wherein receiving, in one of the time slots associated with the synchronization channel, one of the first and second synchronization signals S₁and s₂comprises:
    - receiving the pair of sequences {tilde over (S)}_i, {tilde over (S)}_jsimultaneously.
  - 10. The method of claim 5, comprising:
    - detecting radio frame timing by using information that indicates in which one of the two time slots associated with the synchronization channel the one of the first and second synchronization signals was received.
  - 11. The method of claim 5, wherein identifying the particular cell group by determining with which cell group the pair of received sequences, {tilde over (S)}_i, {tilde over (S)}_j, is uniquely associated comprises using the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jto locate an entry in a look-up table.
  - 12. The method of claim 5, wherein identifying the particular cell group by determining with which cell group the pair of received sequences, {tilde over (S)}_i, {tilde over (S)}_j, is uniquely associated is performed by calculation circuitry.
  - 13. The method of claim 5, wherein using information about whether the sequences {tilde over (S)}_i, {tilde over (S)}_jwere arranged in the first ordering or the second ordering to determine in which one of the two time slots associated with the synchronization channel the received one of the first and second synchronization signals was received comprises using the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jto locate an entry in a look-up table.
  - 14. The method of claim 5, wherein using information about whether the sequences {tilde over (S)}_i, {tilde over (S)}_jwere arranged in the first ordering or the second ordering to determine in which one of the two time slots associated with the synchronization channel the received one of the first and second synchronization signals was received is performed by calculation circuitry.
  - 15. The method of claim 5, comprising:
    - receiving, in an other one of the time slots associated with the synchronization channel, an other one of the first and second synchronization signals;
      
      determining whether a type of cell search procedure to be performed is an inter-frequency cell search procedure;
      
      determining whether the type of cell search procedure to be performed is an inter-radio access technology cell search procedure;
      
      determining whether the type of cell search procedure to be performed is an intra-cell search procedure;
      
      if the type of cell search procedure to be performed is none of the inter-frequency cell search procedure, the inter-radio access technology cell search procedure, or the intra-cell search procedure, then performing;
      
      determining which of the number of predefined sequences best matches the received sequence {tilde over (S)}_iof the other one of the first and second synchronization signals, which of the number of predefined sequences best matches the received sequence {tilde over (S)}_jof the other one of the first and second synchronization signals, and whether the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jof the other one of the first and second synchronization signals were arranged in the first ordering or the second ordering,wherein the cell group identification process further includes determining with which cell group the pair of received sequences, {tilde over (S)}_i, {tilde over (S)}_j, of the other one of the first and second synchronization signals is uniquely associated.

16. An apparatus for indicating timing parameters and an identity of a particular cell group from a number, M, of possible cell groups in a signal transmitted in a cellular communication system that employs a radio frame in a physical layer, the radio frame comprising a number of time slots, the apparatus comprising:
- circuit operable to transmit, in a known one of the time slots of the radio frame, a synchronization signal, S₁, that comprises a pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a first ordering; and
  
  circuit operable to transmit, in another known one of the time slots of the radio frame, a synchronization signal, S₂, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a second ordering, wherein;
  
  each member of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_j, is selected from a group comprising N_seqdifferent sequences, wherein N_seqis at least ceil
- View Dependent Claims (17, 18, 19, 20)
- - 17. The apparatus of claim 16, wherein:
    - the physical layer of the cellular communication system employs Orthogonal Frequency Division Multiplexing;
      
      the circuit operable to transmit, in the known one of the time slots of the radio frame, the synchronization signal, S₁, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in the first ordering effects the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jby transmitting the sequence {tilde over (S)}_ion a first set of one or more sub-carriers, and transmitting the sequence {tilde over (S)}_jon a second set of one or more sub-carriers; and
      
      the circuit operable to transmit, in said another known one of the time slots of the radio frame, the synchronization signal, S₂, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in the second ordering effects the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jby transmitting the sequence {tilde over (S)}_ithe first set of one or more sub-carriers, and transmitting the sequence {tilde over (S)}_ion the second set of one or more sub-carriers.
  - 18. The apparatus of claim 17, wherein the first and second synchronization signals, S₁and S₂, and the sequences {tilde over (S)}_iand {tilde over (S)}_jare all of equal length.
  - 19. The apparatus of claim 16, wherein:
    - in the physical layer of the cellular communication system, symbols of the synchronization signal, S₁, are separated in a frequency domain;
      
      the circuit operable to transmit, in the known one of the time slots of the radio frame, the synchronization signal, S₁, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in the first ordering effects the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jby transmitting the sequence {tilde over (S)}_ion a first set of frequencies, and transmitting the sequence {tilde over (S)}_jon a second set of frequencies; and
      
      the circuit operable to transmit, in said another known one of the time slots of the radio frame, the synchronization signal, S₂, that comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in the second ordering effects the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jby transmitting the sequence {tilde over (S)}_jon the first set of frequencies, and transmitting the sequence {tilde over (S)}_ion the second set of frequencies.
  - 20. The apparatus of claim 16, wherein the use of the first ordering of the sequences only for transmission in the known one of the time slots of the radio frame, and the use of the second ordering of the sequences only for transmission in said another known one of the time slots enables detection of radio frame timing using just one of the synchronization signals, S₁and S₂.

21. An apparatus for detecting timing parameters and an identity of a particular cell group from a number, M, of possible cell groups in a signal received in a cellular communication system that employs a radio frame in a physical layer, the radio frame comprising a number of time slots including two time slots associated with a synchronization channel, the apparatus comprising:
- circuit operable to receive, in one of the time slots associated with the synchronization channel, one of first and second synchronization signals, S₁and S₂, wherein the first synchronization signal S₁comprises a pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a first ordering and the second synchronization signal S₂comprises the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jarranged in a second ordering;
  
  circuit operable to determine which of a number of predefined sequences best matches the received sequence {tilde over (S)}_i, which of the number of predefined sequences best matches the received sequence {tilde over (S)}_j, and whether the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jwere arranged in the first ordering or the second ordering, wherein the number of predefined sequences is selected from a group comprising N_seqdifferent sequences, wherein N_seqis at least ceil
- View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- - 22. The apparatus of claim 21, wherein:
    - the physical layer of the cellular communication system employs Orthogonal Frequency Division Multiplexing;
      
      the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_ito be received on a first set of one or more sub-carriers, and the sequence {tilde over (S)}_jto be received on a second set of one or more sub-carriers; and
      
      the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_jto be received on the first set of one or more sub-carriers, and the sequence {tilde over (S)}_ito be received on the second set of one or more sub-carriers.
  - 23. The apparatus of claim 22, wherein the first and second synchronization signals, S₁and S₂, and the sequences {tilde over (S)}_iand {tilde over (S)}_jare all of equal length.
  - 24. The apparatus of claim 21, wherein:
    - in the physical layer of the cellular communication system, symbols of the synchronization signal, S₁, are separated in a frequency domain;
      
      the first ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_ito be received on a first set of frequencies, and the sequence {tilde over (S)}_jto be received on a second set of frequencies; and
      
      the second ordering of the pair of sequences, {tilde over (S)}_i, {tilde over (S)}_jcauses the sequence {tilde over (S)}_ito be received on the first set of frequencies, and the sequence {tilde over (S)}_ito be received on the second set of frequencies.
  - 25. The apparatus of claim 21, wherein the circuit operable to receive, in one of the time slots associated with the synchronization channel, one of the first and second synchronization signals S₁and S₂comprises:
    - circuit operable to receive the pair of sequences {tilde over (S)}_i, {tilde over (S)}_jsimultaneously.
  - 26. The apparatus of claim 21, comprising:
    - circuit operable to detect radio frame timing by using information that indicates in which one of the two time slots associated with the synchronization channel the one of the first and second synchronization signals was received.
  - 27. The apparatus of claim 21, wherein the circuit operable to identify the particular cell group by determining with which cell group the pair of received sequences, {tilde over (S)}_i, {tilde over (S)}_j, is uniquely associated comprises circuit operable to use the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jto locate an entry in a look-up table.
  - 28. The apparatus of claim 21, wherein the circuit operable to identify the particular cell group by determining with which cell group the pair of received sequences, {tilde over (S)}_i, {tilde over (S)}_j, is uniquely associated comprises calculation circuitry.
  - 29. The apparatus of claim 21, wherein the circuit operable to determine in which one of the two time slots associated with the synchronization channel the one of first and second synchronization signals was received by using information that indicates whether the sequences {tilde over (S)}_i, {tilde over (S)}_jwere received in the first ordering or the second ordering comprises:
    - a look-up table; and
      
      circuit operable to use the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jto locate an entry in the look-up table.
  - 30. The apparatus of claim 21, wherein the circuit operable to determine in which one of the two time slots associated with the synchronization channel the one of first and second synchronization signals was received by using information that indicates whether the sequences {tilde over (S)}_i, {tilde over (S)}_jwere received in the first ordering or the second ordering comprises:
    - calculation circuitry that takes as input the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_j.
  - 31. The apparatus of claim 21, comprising:
    - circuit operable to receive, in an other one of the time slots associated with the synchronization channel, an other one of the first and second synchronization signals;
      
      circuit operable to determine whether a type of cell search procedure to be performed is an inter-frequency cell search procedure;
      
      circuit operable to determine whether the type of cell search procedure to be performed is an inter-radio access technology cell search procedure;
      
      circuit operable to determine whether the type of cell search procedure to be performed is an intra-cell search procedure;
      
      circuit operable to respond to the type of cell search procedure to be performed being none of the inter-frequency cell search procedure, the inter-radio access technology cell search procedure, or the intra-cell search procedure, by performing;
      
      determining which of the number of predefined sequences best matches the received sequence {tilde over (S)}_iof the other one of the first and second synchronization signals, which of the number of predefined sequences best matches the received sequence {tilde over (S)}_jof the other one of the first and second synchronization signals, and whether the pair of received sequences {tilde over (S)}_i, {tilde over (S)}_jof the other one of the first and second synchronization signals were arranged in the first ordering or the second ordering,wherein the cell group identification process further includes determining with which cell group the pair of received sequences, {tilde over (S)}_i, {tilde over (S)}_jof the other one of the first and second synchronization signals is uniquely associated.

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Current Assignee
Telefonaktiebolaget LM Ericsson
Original Assignee
Telefonaktiebolaget LM Ericsson
Inventors
Dahlman, Erik, Lindoff, Bengt, Baldemair, Robert
Primary Examiner(s)
Moe; Aung S
Assistant Examiner(s)
Mered; Habte

Application Number

US12/522,166
Publication Number

US 20090323629A1
Time in Patent Office

1,285 Days
Field of Search

370203-210, 370/304, 370/324, 370/335, 370/337, 370/342, 370/350, 370/395.62, 370503-514, 370/520, 455/13.2, 455/67.16, 455208-209, 455/255, 455/265, 455/434, 455/446, 455/501, 455/502, 455/517, 455/524, 455/525, 375/145, 375/149, 375/356, 375365-368
US Class Current

370/350
CPC Class Codes

H04B 7/2681   Synchronisation of a mobile...

H04J 11/0073   Acquisition of primary sync...

H04J 11/0076   Acquisition of secondary sy...

H04J 13/0077   Multicode, e.g. multiple co...

H04J 13/107   by concatenation

H04J 13/16   Code allocation

H04J 2011/0009   with FDM/FDMA

H04L 27/2613   Structure of the reference ...

H04W 56/00   Synchronisation arrangements

H04W 56/0085   detecting a given structure...

Secondary synchronization sequences for cell group detection in a cellular communications system

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Secondary synchronization sequences for cell group detection in a cellular communications system

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