Mobile communication system, radio base station apparatus, and method for determining uplink reception synchronization

• US 20040109422A1
• Filed: 11/26/2003
• Published: 06/10/2004
• Est. Priority Date: 12/04/2002
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Naito, Takahiro
• Granted Patent: US 7,298,731 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04B 7/2668 Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation, for code acquisition H04B1/7075, for code tracking H04B1/7085
• CPC Class Codes: H04W 56/0085 detecting a given structure in the signal

Abstract

A radio base station apparatus capable of improving accuracy of synchronization detection and making stable determination of reception synchronization without erroneous synchronization determination is provided.

A TFCI bit error determination section re-encodes a decoded TFCI value, and computes the difference between the re-encoded TFCI symbol and a hard-decided symbol of the received TFCI symbol. A TFCI decoding characteristic determination section computes a characteristic indicator value from a correlation result of Fast Hadamard Transform used in a soft decision TFCI decoder. An uplink radio synchronization state determination section determines state transitions of the uplink synchronization state by using synchronization state determination parameters, a reception SIR value computed by a reception SIR determination section, the number of pilot error bits computed by a pilot bit error determination section, the number of error TFCI bits computed by the TFCI bit error determination section, and the TFCI decoding characteristic indicator value computed by the TFCI decoding characteristic determination section.

Claims

1. A mobile communication system including a radio base station apparatus for determining uplink reception synchronization by using a pilot symbol of DPCCH (Dedicated Physical Control Channel) from a mobile station, the system comprising:

means for re-encoding a TFCI (Transport Format Combination Indicator) value that has been once decoded and comparing the re-encoded TFCI value with a TFCI symbol received from the mobile station; and

determination means for using the number of TFCI error bits resulting from the comparison to determine uplink reception synchronization.

2. The mobile communication system according to claim 1 further comprising means for computing a characteristic indicator value from a decoding characteristic resulting from Hadamard transform used in decoding the TFCI value,

wherein the characteristic indicator value is used to determine uplink reception synchronization.

3. The mobile communication system according to claim 2 further comprising control means for determining whether or not to use a reception SIR (Signal to Interference power Ratio) value computed with the pilot symbol, the number of pilot error bits of the pilot symbol, the number of the TFCI error bits, and the characteristic indicator value for the determination of uplink reception synchronization, depending on a radio environment.

4. A radio base station apparatus for determining uplink reception synchronization by using a pilot symbol of DPCCH (Dedicated Physical Control Channel) from a mobile station, the apparatus comprising:

means for re-encoding a TFCI (Transport Format Combination Indicator) value that has been once decoded and comparing the re-encoded TFCI value with a TFCI symbol received from the mobile station; and

determination means for using the number of TFCI error bits resulting from the comparison to determine uplink reception synchronization.

5. The radio base station apparatus according to claim 4 further comprising means for computing a characteristic indicator value from a decoding characteristic resulting from Hadamard transform used in decoding the TFCI value,

wherein the characteristic indicator value is used to determine uplink reception synchronization.

6. The radio base station apparatus according to claim 5 further comprising control means for determining whether or not to use a reception SIR (Signal to Interference power Ratio) value computed with the pilot symbol, the number of pilot error bits of the pilot symbol, the number of the TFCI error bits, and the characteristic indicator value for the determination of uplink reception synchronization, depending on a radio environment.

7. A method for determining uplink reception synchronization in a mobile communication system including a radio base station apparatus for determining uplink reception synchronization by using a pilot symbol of DPCCH (Dedicated Physical Control Channel) from a mobile station, the method comprising the steps, in the radio base station apparatus, of:

re-encoding a TFCI (Transport Format Combination Indicator) value that has been once decoded and comparing the re-encoded TFCI value with a TFCI symbol received from the mobile station; and

using the number of TFCI error bits resulting from the comparison to determine uplink reception synchronization.

8. The method for determining uplink reception synchronization according to claim 7, further comprising the step of computing a characteristic indicator value from a decoding characteristic resulting from Hadamard transform used in decoding the TFCI value,

wherein the characteristic indicator value is used to determine uplink reception synchronization.

9. The method for determining uplink reception synchronization according to claim 8, further comprising the step of determining whether or not to use a reception SIR (Signal to Interference power Ratio) value computed with the pilot symbol, the number of pilot error bits of the pilot symbol, the number of the TFCI error bits, and the characteristic indicator value for the determination of uplink reception synchronization, depending on a radio environment.