COMMUNICATION CONTROL METHOD, MOBILE COMMUNICATION SYSTEM AND MOBILE TERMINAL APPARATUS

• US 20130308540A1
• Filed: 01/05/2012
• Published: 11/21/2013
• Est. Priority Date: 01/07/2011
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Abe, Tetsushi, Takeda, Kazuaki, Ookubo, Naoto, Ishii, Hiroyuki, Sagae, Yuta
• Granted Patent: US 8,995,349 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0067 Rate matching H04L1/0013 and H04L1/08 take precedence
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1822 involving configuration of automatic repeat request [ARQ] with parallel processes
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining

Abstract

The present invention is designated to reduce the deterioration of transmission characteristics upon data transmission, even when soft buffer memory for retransmission control is not sufficiently secured in a mobile terminal apparatus. The present invention provides the steps of, in a base station apparatus (eNB), performing channel coding of information bits (ST 802), performing a rate matching process for the coded bits after interleaving (ST 804), and transmitting transmission data to match the coded bit length after rate matching, to a mobile terminal apparatus (UE)

(ST 806), and, in the mobile terminal apparatus (UE), receiving the transmission data (ST 807), performing channel decoding of the received data (ST 810), and discarding part of the received data in accordance with the size of the soft buffer memory in the mobile terminal apparatus (UE) and storing this in the soft buffer memory (ST 812 and ST 813).

Claims

1. A communication control method comprising the steps of:

in a base station apparatus;

performing channel coding of information bits;

performing a rate matching process of the coded bits after the channel coding; and

transmitting transmission data to match a coded bit length after rate matching, to a mobile terminal apparatus; and

in the mobile terminal apparatus;

receiving the transmission data;

performing channel decoding of the received data; and

discarding part of the received data in accordance with a size of a soft buffer memory of the mobile terminal apparatus and storing in the soft buffer memory.

2. The communication control method according to claim 1, wherein, in the base station apparatus, the rate matching process is performed, without discarding the coded bits after the channel coding in accordance with the size of the soft buffer memory.

3. The communication control method according to claim 1, wherein, in the base station apparatus, the rate matching process is performed after a certain amount of the coded bits after the channel coding are discarded.

4. The communication control method according to claim 3, wherein, in a mobile communication system to be used in a mobile terminal apparatus which is capable of transmission and reception in a plurality of component carriers, the certain amount of the coded bits is determined by the size of the soft buffer memory of a mobile terminal apparatus which is capable of transmission and reception in a single component carrier alone, regardless of the number of component carriers.

5. The communication control method according to claim 1, further comprising a step of retransmitting the transmission data when the base station apparatus receives a retransmission request for the received data from the mobile terminal apparatus,

wherein chase combining and incremental redundancy, which are transmission schemes for parity bits, are switched according to the number of times of retransmissions of the transmission data.

16. The communication control method according to claim 2, further comprising a step of retransmitting the transmission data when the base station apparatus receives a retransmission request for the received data from the mobile terminal apparatus,

wherein chase combining and incremental redundancy, which are transmission schemes for parity bits, are switched according to the number of times of retransmissions of the transmission data.

17. The communication control method according to claim 3, further comprising a step of retransmitting the transmission data when the base station apparatus receives a retransmission request for the received data from the mobile terminal apparatus,

wherein chase combining and incremental redundancy, which are transmission schemes for parity bits, are switched according to the number of times of retransmissions of the transmission data.

18. The communication control method according to claim 4, further comprising a step of retransmitting the transmission data when the base station apparatus receives a retransmission request for the received data from the mobile terminal apparatus,

wherein chase combining and incremental redundancy, which are transmission schemes for parity bits, are switched according to the number of times of retransmissions of the transmission data.

6. A mobile communication system comprising a base station apparatus and a mobile terminal apparatus,

the base station apparatus comprising:

a channel coding section that performs channel coding of information bits;

a rate matching section that performs a rate matching process of the coded bits after channel coding; and

a transmission section that transmits transmission data to match a coded bit length after rate matching, to the mobile terminal apparatus; and

the mobile terminal apparatus comprising;

a receiving section that receives the transmission data;

a channel decoding section that performs channel decoding of the received data; and

a discarding process section that discards part of the received data in accordance with a size of a soft buffer memory of the mobile terminal apparatus.

7. The mobile communication system according to claim 6, wherein the base station apparatus further comprises a discarding process section that discards a certain amount of the coded bits after the channel coding, prior to the rate matching process.

8. The mobile communication system according to claim 7, wherein, in a mobile communication system to be used in a mobile terminal apparatus which is capable of transmission and reception in a plurality of component carriers, the certain amount of the coded bits is determined by the size of the soft buffer memory of a mobile terminal apparatus which is capable of transmission and reception in a single component carrier alone, regardless of the number of component carriers.

9. The mobile communication system according to claim 7, wherein, when the base station apparatus receives a retransmission request for the received data from the mobile terminal apparatus, chase combining and incremental redundancy, which are transmission schemes for parity bits, are switched according to the number of times of retransmissions of the transmission data.

15. The mobile communication system according to claim 8, wherein, when the base station apparatus receives a retransmission request for the received data from the mobile terminal apparatus, chase combining and incremental redundancy, which are transmission schemes for parity bits, are switched according to the number of times of retransmissions of the transmission data.

10. A mobile terminal apparatus comprising:

a receiving section that receives transmission data from a base station apparatus;

a channel decoding section that performs channel decoding of received data; and

a discarding process section that discards part or all of the received data in accordance with a size of a soft buffer memory of the mobile terminal apparatus.

11. The mobile terminal apparatus according to claim 10, further comprising a control section that monitors a state of use of the soft buffer memory and changes an area to store part of all of the received data in accordance with the state of use.

12. The mobile terminal apparatus according to claim 11, wherein the control section, when receiving the transmission data from the base station apparatus in a plurality of component carriers, shares the soft buffer memory between the plurality of component carriers.

13. The mobile terminal apparatus according to claim 12, wherein the control section assigns received data to correspond to an HARQ process where an error is found in a first component carrier and received data to correspond to an HARQ process where an error is found in a second component carrier, to the soft buffer memory.

14. The mobile terminal apparatus according to claim 11, wherein the control section controls an operation of the discarding process section in accordance with the area to store part of the received data.