Base station which communicates according to a retransmission control
There are provided scheduling and a resend control system, which match simultaneous communications using a plurality of carriers. For individual carriers to be used, the simultaneous resend control of the carriers is made by notifying channel information and a data decoding result and by managing the resend numbers. Even in case the communications are performed by using the carriers simultaneously between a base station and a terminal, the scheduling can be done to contain the resend control. It is also possible to improve the communication quality and the throughput.
1. A communication control method for a wireless communication system having at least one base station and a plurality of terminals, which allows communication involving retransmission control by use of a plurality of carriers, the method comprising:
a first step of obtaining, by the base station, a result of decoding data related to a terminal which stores transmitted data;
a second step of determining, by the base station, based on a number of retransmissions of data transmitted by a first carrier from the base station to the terminal and the data decoding result, whether or not to retransmit the transmitted data by the first carrier;
a third step of, upon the base station determining to retransmit the transmitted data, scheduling, by the base station, data waiting to be transmitted for carriers other than the first carrier including the data that is determined to be retransmitted; and
a fourth step of, upon the base station determining not to retransmit the transmitted data, scheduling, by the base station, data waiting to be transmitted for the first carrier and the other carriers.
2. The communication control method according to claim 1 , further comprising the step of obtaining a result of determination on a channel condition of each of carriers related to each of the terminals,
wherein the scheduling is performed by using the channel condition of each of the carriers related to the terminal which stores the data waiting to be transmitted.
3. The communication control method according to claim 2 , wherein the result of determination on the channel condition of each of the carriers related to each of the terminals is notified from each of the terminals to the base station.
4. The communication control method according to claim 1 , wherein the transmitted data which requires retransmission is scheduled as data waiting to be transmitted.
5. The communication control method according to claim 4 , wherein, upon the transmitted data required to be retransmitted being scheduled as data waiting to be transmitted, the transmitted data required to be retransmitted is preferentially selected as a candidate for data to be transmitted.
6. The communication control method according to claim 4 , wherein, upon the transmitted data required to be retransmitted being scheduled as data waiting to be transmitted, the transmitted data required to be retransmitted is non-preferentially selected as a candidate for data to be transmitted.
7. The communication control method according to claim 1 , wherein the data to be retransmitted is the same part or a different part of the same code words of the transmitted data.
8. A base station, which communicates with a plurality of terminals according to retransmission control by use of a plurality of carriers, comprising:
a receiver for receiving signals corresponding to the plurality of carriers;
a control unit for controlling retransmission and scheduling corresponding to the plurality of carriers; and
a transmitter for transmitting the signals corresponding to the plurality of carriers for which the retransmission control or the scheduling has been performed,
wherein the receiver receives a data decoding result from a terminal which stores transmitted data;
wherein the controlling unit:
determines, based on a number of retransmissions of the transmitted data and the data decoding result, whether or not to retransmit the transmitted data by a first carrier used for transmitting the transmitted data to the terminal;
upon determining to retransmit the transmitted data, schedules data waiting to be transmitted for carriers other than the first carrier including the data that is determined to be retransmitted; and
upon determining not to retransmit the transmitted data, schedules data waiting to be transmitted for the first carrier and the other carriers.
9. The base station according to claim 8 , wherein:
the controlling unit determines a channel condition of each of carriers related to each of the terminals based on the signals received by the receiver; and
the controlling unit performs, in the scheduling of data waiting to be transmitted, the scheduling by use of the channel condition of each of the carriers related to the terminal which stores the data waiting to be transmitted.
10. The base station according to claim 9 , wherein the receiver receives, from each of the terminals, a result of the determination on the channel condition of each of the carriers related to each of the terminals.
11. The base station according to claim 8 , wherein the controlling unit sets the transmitted data which requires retransmission as a scheduled as data waiting to be transmitted.
12. The base station according to claim 8 , wherein, upon the transmitted data required to be retransmitted being scheduled as data waiting to be transmitted, the controlling unit preferentially selects the transmitted data required to be retransmitted as a candidate for data to be transmitted.
13. The base station according to claim 8 , wherein, upon the transmitted data required to be retransmitted being scheduled as data waiting to be transmitted, the controlling unit non-preferentially selects the transmitted data required to be retransmitted as a candidate for data to be transmitted.
14. The base station according to claim 8 , wherein the data to be retransmitted is the same part or a different part of the same code words of the transmitted data.