USER TERMINAL, RADIO BASE STATION AND RADIO COMMUNICATION METHOD

• US 20170347350A1
• Filed: 10/09/2015
• Published: 11/30/2017
• Est. Priority Date: 11/06/2014
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takeda, Kazuaki, Yasukawa, Shimpei, Moroga, Hideyuki, Nagata, Satoshi
• Granted Patent: US 11,089,574 B2
• Time in Patent Office: Days
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

The present invention is designed to optimize the uplink access procedure even when the band to use is limited to partial narrow bands in a system band. A user terminal, in which the band to use is limited to a partial narrow band in a system band, has a receiving section that receives system information that includes indication information of an uplink carrier frequency, from a radio base station, as system information for narrow bands, which is different from system information for the system band, and a transmission section that transmits a random access preamble to the radio base station in one of a plurality of narrow bands that are specified by the indication information of the uplink carrier frequency.

Claims

1. A user terminal, in which a bandwidth is limited to a narrow band in a system band, the user terminal comprising:

a receiving section that receives system information that includes indication information of an uplink carrier frequency, from a radio base station, as system information for narrow bands, which is different from system information for the system band; and

a transmission section that transmits a random access preamble to the radio base station in one of a plurality of narrow bands that are specified by the indication information of the uplink carrier frequency.

2. The user terminal according to claim 1, wherein:

the indication information is a frequency value to indicate an uplink carrier frequency and an offset value to apply to the frequency value; and

the transmission section transmits the random access preamble to the radio base station in one of a plurality of narrow bands that are specified by the frequency value of the uplink carrier frequency and another frequency value that is determined by adding the offset value to the frequency value.

3. The user terminal according to claim 1, wherein the transmission section transmits the random access preamble to the radio base station in one of the plurality of narrow bands, and, when the transmission of the random access preamble fails, transmits the random access preamble to the radio base station in another one of the plurality of narrow bands.

4. The user terminal according to claim 1, wherein:

the indication information is configured so that the plurality of narrow bands adjoin an uplink control channel band placed on either edge of the system band; and

the transmission section transmits the random access preamble to the radio base station in one of the plurality of narrow bands.

5. The user terminal according to claim 1, wherein the receiving section receives a random access response from the radio base station, as an acknowledgment signal in response to the random access preamble, in a resource that is linked with a signal sequence and/or a frequency of the random access preamble.

6. The user terminal according to claim 5, wherein the transmission section transmits a connection request message to the radio base station, as an acknowledgment signal in response to the random access response, in a narrow band in which a random access preamble was transmitted.

7. The user terminal according to claim 5, wherein, when the transmission section transmits the random access preamble to the radio base station by subjecting the random access preamble to frequency hopping among the plurality of narrow bands, the transmission section transmits a connection request message to the radio base station, as an acknowledgment signal in response to the random access response, in a frequency in which a random access preamble was transmitted.

8. The user terminal according to claim 1, wherein the receiving section receives system information that includes indication information of a downlink frequency, from the radio base station, as the system information for narrow bands, and receives a downlink signal in one of a plurality of narrow bands that are specified by the indication information of the downlink frequency.

11. The user terminal according to claim 2, wherein the transmission section transmits the random access preamble to the radio base station in one of the plurality of narrow bands, and, when the transmission of the random access preamble fails, transmits the random access preamble to the radio base station in another one of the plurality of narrow bands.

12. The user terminal according to claim 2, wherein:

the indication information is configured so that the plurality of narrow bands adjoin an uplink control channel band placed on either edge of the system band; and

the transmission section transmits the random access preamble to the radio base station in one of the plurality of narrow bands.

13. The user terminal according to claim 3, wherein:

the indication information is configured so that the plurality of narrow bands adjoin an uplink control channel band placed on either edge of the system band; and

the transmission section transmits the random access preamble to the radio base station in one of the plurality of narrow bands.

9. A radio base station that communicates with a user terminal in which a band to use is limited to a partial narrow band in a system band, the radio base station comprising:

a generating section that generates system information that includes indication information of an uplink carrier frequency, as system information for narrow bands, which is different from system information for the system band;

a transmission section that transmits the system information for narrow bands to the user terminal; and

a receiving section that receives a random access preamble from the user terminal in one of a plurality of narrow bands that are specified by the indication information of the uplink carrier frequency.

10. A radio communication method to allow a user terminal, in which a band to use is limited to a partial narrow band in a system band, and a radio base station to communicate, the radio communication method comprising the steps in which:

the radio base station generates system information that includes indication information of an uplink carrier frequency, as system information for narrow bands, which is different from system information for the system band, and transmits the generated system information to the user terminal; and

the user terminal receives the system information for narrow bands from the radio base station, and transmits a random access preamble to the radio base station in one of a plurality of narrow bands that are specified by the indication information of the uplink carrier frequency.