Communication System, Base Station Apparatus, Mobile Station Apparatus, and Communication Method

1. A mobile station apparatus configured to communicate with a base station apparatus, the mobile station apparatus comprising a pseudo-random sequence generator configured to being initialized, at a beginning of each radio frame, with an initial value c init using a first parameter, wherein in a case that a second parameter is set, the pseudo-random sequence generator is configured to be initialized with the initial value c init using the second parameter, for an initialization of a pseudo-random sequence for each of a cyclic shift (CS) for a physical uplink control channel (PUCCH), sequence group hopping (SGH) of a demodulation reference signal (DMRS) for the PUCCH and sequence hopping (SH) of a demodulation reference signal (DMRS) for the PUCCH.

2. The mobile station apparatus according to claim 1 , wherein in a case that the second parameter is set, the pseudo-random sequence generator is configured to be initialized with the initial value c init using the second parameter, for an initialization of a pseudo-random sequence for each of sequence group hopping (SGH) of a demodulation reference signal (DMRS) for a physical uplink shared channel (PUSCH) and sequence hopping (SH) of a demodulation reference signal (DMRS) for the PUSCH.

3. The mobile station apparatus according to claim 1 , further comprising: a reception unit configured to receive, from the base station apparatus, information indicating the second parameter.

4. A method of a mobile station apparatus configured to communicate with a base station apparatus, the method comprising: initializing a pseudo-random sequence generator, at a beginning of each radio frame, with an initial value c init using a first parameter, wherein in a case that a second parameter is set, the step of initializing the pseudo-random sequence generator uses the second parameter, for an initialization of a pseudo-random sequence for each of a cyclic shift (CS) for a physical uplink control channel (PUCCH), sequence group hopping (SGH) of a demodulation reference signal (DMRS) for the PUCCH and sequence hopping (SH) of a demodulation reference signal (DMRS) for the PUCCH.

5. An integrated circuit to be mounted on a mobile station apparatus that is configured to communicate with a base station apparatus, the integrated circuit is configured to control a process comprising: initializing a pseudo-random sequence generator, at a beginning of each radio frame, with an initial value c init using a first parameter, wherein in a case that a second parameter is set, the step of initializing the pseudo-random sequence generator uses the second parameter, for an initialization of a pseudo-random sequence for each of a cyclic shift (CS) for a physical uplink control channel (PUCCH), sequence group hopping (SGH) of a demodulation reference signal (DMRS) for the PUCCH and sequence hopping (SH) of a demodulation reference signal (DMRS) for the PUCCH.

6. A base station apparatus configured to communicate with a mobile station apparatus, the base station apparatus comprising: a radio resource control unit configured to set a first parameter and a second parameter, and a transmission unit configured to transmit the first parameter and/or the second parameter to the mobile station apparatus, wherein the second parameter is used for an initialization of a pseudo-random sequence for each of a cyclic shift (CS) for a physical uplink control channel (PUCCH), sequence group hopping (SGH) of a demodulation reference signal (DMRS) for the PUCCH and sequence hopping (SH) of a demodulation reference signal (DMRS) for the PUCCH.

7. The base station apparatus according to claim 6 , comprising: a reception data demodulation unit configured to demodulate data that is transmitted using a physical channel from the mobile station apparatus, on the basis of a pseudo-random sequence that is initialized with an initial value c init using the second parameter, in a case that the transmission unit transmits the second parameter to the mobile station apparatus.

8. The mobile station apparatus according to claim 1 , wherein the first parameter is a physical layer cell identity to be set based on a first Synchronization Signal and a second Synchronization Signal or is the physical layer cell identity to be set by a higher layer signaling, and the second parameter is an identity to be set by the high layer signaling, wherein each of the first parameter and the second parameter is independently set.