Direct communication by use of frequency of neighboring cell
Provided is a technology relating to a terminal device, a base station apparatus, a communication system, a communication method, and an integrated circuit, in all of which it is possible that a communication procedure relating to device-to-device communication is efficiently performed. A terminal device that is capable of direct communication with a different terminal device makes a determination of whether or not transmission and reception of data relating to the direct communication at a frequency in a serving cell are not possible and transmission and reception of data relating to the direct communication at a frequency in a neighboring cell are possible, based on capability information relating to a combination of frequency bands that are supported by the terminal device, the frequency in the serving cell, and the frequency in the neighboring cell, and starts evaluation for selecting the neighboring cell, at a frequency in the neighboring cell in which the transmission and reception of the data relating to the direct communication are possible, in a case where the terminal device is interested in the direct communication.
1. A first terminal device that is capable of direct communication with a second terminal device different from the first terminal device, the first terminal device comprising:
reception circuitry that receives first system information including cell selection parameters and second system information indicating a radio resource for the direct communication, the cell selection parameters including an offset for cell selection relating to the direct communication, the offset being used for an evaluation of a cell on a frequency which supports the direct communication, and the frequency being a non-serving frequency; and
cell selection circuitry that determines that the first terminal device is configured to perform the direct communication on the frequency using the radio resource for the direct communication, in a case that at least one neighboring cell is detected on the frequency by the evaluation,
wherein the cell selection circuitry performs the evaluation based on the cell selection parameters and a result of a measurement for the neighboring cell.
2. The first terminal device according to claim 1 ,
wherein the cell selection circuitry, in a case that the neighboring cell in which the direct communication at the frequency is performed has been selected, performs evaluation for reselecting a neighboring cell for the cell in which the direct communication is performed.
3. A communication method of a first terminal device that is capable of direct communication with a second terminal device different from the first terminal device, the communication method comprising:
receiving first system information including cell selection parameters and second system information indicating a radio resource for the direct communication, the cell selection parameters including an offset for cell selection relating to the direct communication, the offset being used for an evaluation of a cell on a frequency which supports the direct communication, and the frequency being a non-serving frequency; and
in a case that at least one neighboring cell is detected on the frequency by the evaluation,
performing measurement for a neighboring cell;
performing the evaluation for the cell selection based on the cell selection parameters and a result of the measurement; and
determining that the first terminal device is configured to perform the direct communication on the frequency using the direct communication resources.
4. The communication method according to claim 3 , further comprising:
performing evaluation for reselecting a neighboring cell for the cell in which the direct communication is performed in a case that the neighboring cell in which the direct communication at the frequency is performed has been selected.
5. An integrated circuit that is built into a first terminal device that is capable of direct communication with a second terminal device different from the first terminal device, the integrated circuit causing the first terminal device to perform at least:
receiving first system information including cell selection parameters and second system information indicating a radio resource for the direct communication, the cell selection parameters including an offset for cell selection relating to the direct communication, the offset being used for an evaluation of a cell on a frequency which supports the direct communication, and the frequency being a non-serving frequency; and
in a case that at least one neighboring cell is detected on the frequency by the evaluation,
performing measurement for a neighboring cell;
performing the evaluation for the cell selection based on the cell selection parameters and a result of the measurement; and
determining that the first terminal device is configured to perform the direct communication on the frequency using the direct communication resources.