RADIO COMMUNICATION SYSTEM, USER TERMINAL AND RADIO COMMUNICATION METHOD

• US 20140293947A1
• Filed: 11/08/2012
• Published: 10/02/2014
• Est. Priority Date: 11/09/2011
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Nishikawa, Daisuke, Takeda, Kazuaki, Nagata, Satoshi, Kishiyama, Yoshihisa, Uchino, Tooru, Sagae, Yuta
• Granted Patent: US 9,717,084 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/535 based on resource usage policies

Abstract

To ensure stable operation of a user terminal even in the case where the user terminal is instructed to transmit uplink signals at different transmission timings with a plurality of component carriers, in a radio communication system provided with a radio base station apparatus that indicates transmission timings of uplink signals for each component carrier, and a user terminal that transmits an uplink signal at a transmission timing set based on transmission timing information indicated from the radio base station apparatus and the like, it is a feature that the radio base station apparatus indicates different transmission timing information in a plurality of component carriers, and that the user terminal avoids simultaneous transmission of uplink signals in the case of performing communications using a plurality of contiguous component carriers.

Claims

1. A radio communication system comprising:

a radio base station apparatus that indicates transmission timing information of uplink signals for each component carrier; and

a user terminal that transmits an uplink signal based on information including the transmission timing information indicated from the radio base station apparatus,

wherein the radio base station apparatus indicates different transmission timing information in a plurality of component carriers, and

the user terminal avoids simultaneous transmission of uplink signals in performing communications using a plurality of contiguous component carriers.

2. The radio communication system according to claim 1, wherein the plurality of component carriers is comprised of a primary cell and at least one secondary cell, and with respect to portions in which transmission timings overlap in the primary cell and the secondary cell, the user terminal transmits a signal in the primary cell, while controlling a signal in the secondary cell not to overlap, and thereby avoids simultaneous transmission of uplink signals.

3. The radio communication system according to claim 2, wherein the user terminal delays a start position of the transmission timing of the signal in the secondary cell.

4. The radio communication system according to claim 3, wherein the user terminal delays the start position of the transmission timing of the signal in the secondary cell by rate matching.

5. The radio communication system according to claim 3, wherein the user terminal delays the start position of the transmission timing of the signal in the secondary cell by puncturing.

6. The radio communication system according to claim 2, wherein the user terminal omits transmission of the signal in the secondary cell.

7. The radio communication system according to claim 2, wherein when uplink data channel signals overlap in the plurality of component carriers, the user terminal controls an uplink data channel signal in the secondary cell not to overlap.

8. The radio communication system according to claim 2, wherein when an uplink data channel signal and an uplink control channel signal overlap in the plurality of component carriers, the user terminal controls the uplink data channel signal in the secondary cell not to overlap.

9. The radio communication system according to claim 2, wherein when an uplink data channel signal and an uplink sounding reference signal overlap in the plurality of component carriers, the user terminal controls the uplink data channel signal in the secondary cell or the uplink sounding reference signal not to overlap.

10. The radio communication system according to claim 2, wherein when an uplink data channel signal and an uplink sounding reference signal overlap in the plurality of component carriers, the user terminal controls one of the uplink data channel signal and the uplink sounding reference signal not to overlap.

11. The radio communication system according to claim 2, wherein when an uplink data channel signal and a random access channel signal overlap in the plurality of component carriers, the user terminal controls the uplink data channel signal in the secondary cell or the random access channel signal not to overlap.

12. The radio communication system according to claim 2, wherein when an uplink data channel signal and a random access channel signal overlap in the plurality of component carriers, the user terminal always controls one of the uplink data channel signal and the random access channel signal not to overlap.

13. The radio communication system according to claim 2, wherein when an uplink control channel signal and an uplink sounding reference signal overlap in the plurality of component carriers, the user terminal controls the uplink sounding reference signal not to overlap.

14. The radio communication system according to claim 2, wherein when an uplink control channel signal and a random access channel signal overlap in the plurality of component carriers, the user terminal controls the random access channel signal not to overlap.

15. The radio communication system according to claim 2, wherein when an uplink sounding reference signal and a random access channel signal overlap in the plurality of component carriers, the user terminal always controls one of the uplink sounding reference signal and the random access channel signal not to overlap.

16. The radio communication system according to claim 1, wherein the user terminal permits simultaneous transmission of uplink signals in performing communications using a plurality of non-contiguous component carriers.

17. The radio communication system according to claim 16, wherein when total transmission power of uplink signals to undergo simultaneous transmission exceeds maximum transmission power determined in the user terminal, the user terminal avoids simultaneous transmission of the uplink signals.

18. The radio communication system according to claim 16, wherein when total transmission power of uplink signals to undergo simultaneous transmission exceeds maximum transmission power determined in the user terminal, the user terminal adjusts transmission power of an uplink signal to undergo the simultaneous transmission to a certain transmission power value below the maximum transmission power.

19. A user terminal comprising:

a receiving section that receives transmission timing information of uplink signals indicated for each component carrier from a radio base station apparatus; and

a determining section that determines transmission of an uplink signal corresponding to a difference between transmission timings set based on information including the transmission timing information of uplink signals, wherein in performing communications using a plurality of contiguous component carriers, when a difference exists between transmission timings of the uplink signals, the determining section avoids simultaneous transmission of the uplink signals.

20. The user terminal according to claim 19, wherein in performing communications using a plurality of non-contiguous component carriers, even when a difference exists between transmission timings of the uplink signals, the determining section permits simultaneous transmission of the uplink signals.

21. A radio communication method provided with a radio base station apparatus that indicates transmission timing information of uplink signals for each component carrier, and a user terminal that transmits an uplink signal at a transmission timing set based on information including the transmission timing information indicated from the radio base station apparatus, comprising the steps of:

in the radio base station apparatus, indicating different transmission timing information in a plurality of component carriers;

in the user terminal,

determining whether or not to perform communications using a plurality of contiguous component carriers; and

avoiding simultaneous transmission of uplink signals in performing communications using the plurality of contiguous component carriers.

22. The radio communication method according to claim 21, further comprising the steps of:

in the user terminal, determining whether or not to perform communications using a plurality of non-contiguous component carriers; and

permitting simultaneous transmission of uplink signals in performing communications using the plurality of non-contiguous component carriers.