Radio transmission device and radio transmission method

1. A mobile station for transmitting a random access preamble, comprising:

communication control circuitry, which, in operation:

selects at least one of:

preamble(s) contained in a first Random Access Preamble group;

preamble(s) contained in a second Random Access Preamble group; and

preamble(s) contained in a third Random Access Preamble group,

wherein, a preamble contained in the first Random Access Preamble group is selected when a message size based on data available for transmission does not meet a first condition or when a value calculated based on a reference signal received power of downlink does not meet a second condition, a preamble contained in the second Random Access Preamble group is selected when the message size based on data available for transmission meets the first condition and the value calculated based on the reference signal received power of downlink meets the second condition, and a preamble contained in the third Random Access Preamble group is selected for a handover, independent of the message size based on data available for transmission and the value calculated based on the reference signal received power of downlink;

generates a preamble from among the preamble(s) when the first Random Access Preamble group is selected;

generates a preamble from among the preamble(s) when the second Random Access Preamble group is selected;

generates a preamble from among the preamble(s) when the third Random Access Preamble group is selected; and

transmits at least one generated preamble.

2. The mobile station of claim 1 wherein a number of the preamble(s) to be included in the first Random Access Preamble group, a number of the preamble(s) to be included in the second Random Access Preamble group, and a number of the preamble(s) to be included in the third Random Access Preamble group are determined based on information broadcasted from a base station.

3. The mobile station of claim 1 wherein the data available for transmission is indicated as a buffer status.

4. The mobile station of claim 1 wherein the value calculated based on the reference signal received power of downlink is a downlink Channel Quality Indicator (DL CQI).

5. The mobile station of claim 1 wherein the value calculated based on the reference signal received power of downlink is a transmission power margin.

6. The mobile station of claim 1 wherein the preamble is generated from the selected Random Access Preamble group such that each of the preambles in the selected Random Access Preamble group has an equal probability of being generated.

7. A random access preamble transmission method to be performed by a mobile station comprising:

selecting at least one of:

a preamble contained in a first Random Access Preamble group;

a preamble contained in a second Random Access Preamble group; and

a preamble contained in a third Random Access Preamble group,

wherein, a preamble contained in the first Random Access Preamble group is selected when a message size based on data available for transmission does not meet a first condition or when a value calculated based on a reference signal received power of downlink does not meet a second condition, a preamble contained in the second Random Access Preamble group is selected when the message size based on data available for transmission meets the first condition and the value calculated based on the reference signal received power of downlink meets the second condition, and a preamble contained in the third Random Access Preamble group is selected for a handover, independent of the message size based on data available for transmission and the value calculated based on the reference signal received power of downlink;

generating a preamble from among the preamble(s) when the first Random Access Preamble group is selected;

generating a preamble from among the preamble(s) when the second Random Access Preamble group is selected;

generating a preamble from among the preamble(s) when the third Random Access Preamble group is selected; and

transmitting at least one generated preamble.

8. The random access preamble transmission method of claim 7 wherein a number of the preamble(s) to be included in the first Random Access Preamble group, a number of the preamble(s) to be included in the second Random Access Preamble group, and a number of the preamble(s) to be included in the third Random Access Preamble group are determined based on information broadcasted from a base station.

9. The random access preamble transmission method of claim 7 wherein the data available for transmission is indicated as a buffer status.

10. The random access preamble transmission method of claim 7 wherein the value calculated based on the reference signal received power of downlink is a downlink Channel Quality Indicator (DL CQI).

11. The random access preamble transmission method of claim 7 wherein the value calculated based on the reference signal received power of downlink is a transmission power margin.

12. The random access preamble transmission method of claim 7 wherein a preamble is generated from the selected Random Access Preamble group such that each of the preambles in the selected Random Access Preamble group has an equal probability of being generated.

13. An integrated circuit, comprising:

communication control circuitry, which, in operation:

selects at least one of:

preamble(s) contained in a first Random Access Preamble group;

preamble(s) contained in a second Random Access Preamble group; and

preamble(s) contained in a third Random Access Preamble group,

wherein, a preamble contained in the first Random Access Preamble group is selected when a message size based on data available for transmission does not meet a first condition or when a value calculated based on a reference signal received power of downlink does not meet a second condition, a preamble contained in the second Random Access Preamble group is selected when the message size based on data available for transmission meets the first condition and the value calculated based on the reference signal received power of downlink meets the second condition, and a preamble contained in the third Random Access Preamble group is selected for a handover, independent of the message size based on data available for transmission and the value calculated based on the reference signal received power of downlink;

generates a preamble from among the preamble(s) when the first Random Access Preamble group is selected;

generates a preamble from among the preamble(s) when the second Random Access Preamble group is selected; and

generates a preamble from among the preamble(s) when the third Random Access Preamble group is selected; and

one or more output nodes, which, in operation, output at least one generated preamble.

14. The integrated circuit of claim 13 wherein a number of the preamble(s) to be included in the first Random Access Preamble group, a number of the preamble(s) to be included in the second Random Access Preamble group, and a number of the preamble(s) to be included in the third Random Access Preamble group are determined based on information broadcast by a base station.

15. The integrated circuit of claim 12 wherein the data available for transmission is indicated as a buffer status.

16. The integrated circuit of claim 13 wherein the value calculated based on the reference signal received power of downlink is a downlink Channel Quality Indicator (DL CQI).

17. The integrated circuit of claim 13 wherein the value calculated based on the reference signal received power of downlink is a transmission power margin.

18. The integrated circuit of claim 13 wherein the preamble is generated from the selected Random Access Preamble group such that each of the preambles in the selected Random Access Preamble group has an equal probability of being generated.