Method and apparatus of establishing a synchronization signal in a communication system
First Claim
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1. A method of establishing a synchronization signal for transmission in a communication system, the method comprising:
- defining a set of discrete Fourier frequency coefficients,transforming the set of discrete Fourier frequency coefficients into a discrete time representation, andusing the discrete time representation as the synchronization signal in the communication system,wherein the set of discrete Fourier frequency coefficients represents a mapping of a centrally symmetric number sequence onto discrete Fourier frequency coefficients, and the centrally symmetric number sequence, du[n], is obtained by puncturing a central element of a Zadoff-Chu sequence of odd length L+1, so that du[n] is given by where WN=exp(−
j2π
/N), for positive integer N.
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Abstract
A method of establishing a synchronization signal in a communication system is disclosed. A set of discrete Fourier frequency coefficients is defined and transformed into a discrete time representation, the discrete time representation being particularly useful as a synchronization signal. According to example embodiments of the invention, signal symmetry is exploited. Preferably, the center frequency, also referred to as DC subcarrier, is not used for transmission. The invention also concerns a transmitter and receiver of a communication system.
21 Citations
15 Claims
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1. A method of establishing a synchronization signal for transmission in a communication system, the method comprising:
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defining a set of discrete Fourier frequency coefficients, transforming the set of discrete Fourier frequency coefficients into a discrete time representation, and using the discrete time representation as the synchronization signal in the communication system, wherein the set of discrete Fourier frequency coefficients represents a mapping of a centrally symmetric number sequence onto discrete Fourier frequency coefficients, and the centrally symmetric number sequence, du[n], is obtained by puncturing a central element of a Zadoff-Chu sequence of odd length L+1, so that du[n] is given by where WN=exp(−
j2π
/N), for positive integer N.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
where, du[n], n=0, 1, . . . , L−
1, represents the number sequence and L is a length of the number sequence, and Hu[l], l=0, 1, . . . , N−
1, represents the discrete Fourier frequency coefficients and N is the number of discrete Fourier frequency coefficients.
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5. The method according to claim 4, wherein the number sequence, du[n], is of length L and has a property such that du[n]=du[L−
- 1−
n], n=0, 1, . . . , L/2−
1.
- 1−
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6. The method according to claim 1, wherein the centrally symmetric number sequence is a punctured Zadoff-Chu sequence of either of three root indices, u, u=u1, u=u2 or u=u3.
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7. The method according to claim 6, wherein for a first root index u1, a second root index is L+1−
- u1.
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8. The method according to claim 6, wherein each of the root indices corresponds to a cell-specific synchronization sequence in a cellular communication system.
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9. The method according to claim 1, wherein the set of discrete Fourier frequency coefficients are transformed into a discrete time representation, su[k], corresponding to:
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for Fourier frequency coefficients Hu[l], l=0, 1, . . . , N−
1, where N is a number of discrete Fourier frequency coefficients of the set.
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10. The method according to claim 1, wherein the synchronization signal provides OFDM symbol timing synchronization.
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11. A transmitter for a communication system, the transmitter comprising:
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a microprocessor adapted to establish a synchronization signal for transmission, the synchronization signal representing; a set of discrete Fourier frequency coefficients as defined, the set of discrete Fourier frequency coefficients being transformed into a discrete time representation, the set of discrete Fourier frequency coefficients being defined to represent mapping of a centrally symmetric number sequence onto discrete Fourier frequency coefficients, and the centrally symmetric number sequence, du[n], is obtained by puncturing a central element of a Zadoff-Chu sequence of odd length L+1, so that du[n] is given by where WN=exp(−
j2π
/N), for positive integer N, andcircuitry adapted to send the synchronization signal as established, the circuitry being arranged for sending the synchronization signal corresponding to the discrete time representation in the communication system.
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12. A receiver for a communication system, the receiver comprising:
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circuitry for receiving a synchronization signal, and a microprocessor being adapted to synchronize the receiver to the synchronization signal, the synchronization signal representing; a set of discrete Fourier frequency coefficients as defined, the set of discrete Fourier frequency coefficients being transformed into a discrete time representation, the set of discrete Fourier frequency coefficients being defined to represent mapping of a centrally symmetric number sequence onto discrete Fourier frequency coefficients, and the centrally symmetric number sequence, du[n], is obtained by puncturing a central element of a Zadoff-Chu sequence of odd length L+1, so that du[n] is given by where WN=exp(−
j2π
/N), for positive integer N, andwherein the circuitry for receiving is arranged for receiving a synchronization signal corresponding to the discrete time representation in the communication system. - View Dependent Claims (13, 14, 15)
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Specification