Method and wireless device for transmitting random-access preamble by means of single-tone method
Disclosed is a method for a wireless device for transmitting a random-access preamble. The method may comprise the steps of: generating a sequence of a random-access preamble; and mapping the sequence of a random-access preamble to one sub-carrier wave from among 12 sub-carrier waves of a frequency domain. The mapping step may comprise the step for carrying out a first hop between a plurality of sub-regions. Each sub-region may comprise a previously set number of sub-carrier waves. The mapping step may additionally comprise the step for carrying out a second hop from among the sub-carrier waves within any one sub-region.
1. A method for transmitting a random access preamble, the method performed by a wireless device and comprising:
performing a single tone transmission of the random access preamble,
wherein the single tone transmission of the random access preamble uses a 3.75 kHz subcarrier spacing and includes:
generating a sequence of the random access preamble;
mapping the sequence of the random access preamble onto one subcarrier among 12 subcarriers in a frequency domain; and
transmitting the sequence of the random access preamble which is mapped onto the one subcarrier;
wherein the mapping of the sequence of the random access preamble includes:
performing a first hopping among plural groups, each of which includes a pre-configured number of subcarriers, and
performing a second hopping among the pre-configured number of subcarriers in one group of the plural groups.
2. The method of claim 1 , wherein the performing of the first hopping comprises:
selecting one group among the plural groups; and
performing a hopping into the selected group.
3. The method of claim 2 , wherein the performing of the second hopping comprises:
selecting one subcarrier among plural subcarriers included in the selected group;
performing the hopping into the selected subcarrier; and
mapping the sequence of the random access preamble onto the selected subcarrier.
4. The method of claim 1 , further comprising:
receiving information on one or more of the plural groups via a higher layer signal.
5. The method of claim 4 , wherein the information on one or more of the plural groups received via the higher layer signal includes
information on the pre-configured number of the subcarriers included in each group.
6. The method of claim 5 , wherein the information on one or more of the plural groups received via the higher layer signal includes
information on a frequency offset.
7. The method of claim 1 , wherein the sequence of the random access preamble is generated based on an identifier of a narrowband internet of things (NB-IoT).
8. The method of claim 1 , further comprising:
receiving a physical downlink control channel (PDCCH) order for triggering a transmission of the random access preamble.
9. The method of claim 8 , wherein the PDCCH order includes
downlink control information (DCI) including information on the subcarrier on which the random access preamble is transmitted.
10. A wireless device for transmitting a random access preamble, the wireless device comprising:
a transceiver; and
a processor configured to control the transceiver and configured to:
perform a single tone transmission of the random access preamble,
wherein the single tone transmission of the random access preamble uses a 3.75 kHz subcarrier spacing and includes:
generating a sequence of the random access preamble;
mapping the sequence of the random access preamble onto one subcarrier among 12 subcarriers in a frequency domain,
transmitting the sequence of the random access preamble which is mapped onto the one subcarrier;
wherein the mapping of the sequence of the random access preamble includes:
performing a first hopping among plural groups, each of which includes a pre-configured number of subcarriers, and
performing a second hopping among the pre-configured number of subcarriers in one group of the plural groups.
11. The wireless device of claim 10 , wherein for performing the first hopping, the processor is further configured to:
select one group among the plural groups; and
perform a hopping into the selected group.
12. The wireless device of claim 11 , wherein for performing the second hopping, the processor is further configured to:
select one subcarrier among plural subcarriers included in the selected group;
perform the hopping into the selected subcarrier; and
map the sequence of the random access preamble onto the selected subcarrier.
13. The wireless device of claim 10 , wherein the transceiver is configured to:
receive information on one or more of the plural groups via a higher layer signal.
14. The wireless device of claim 10 , wherein the transceiver is configured to:
receive a physical downlink control channel (PDCCH) order for triggering a transmission of the random access preamble.
15. The wireless device of claim 14 , wherein the PDCCH order includes
downlink control information (DCI) including information on the subcarrier on which the random access preamble is transmitted.