Random access method and apparatus and system
Embodiments of the present invention provide a random access method and apparatus and system. Where, the method includes: selecting randomly, by UE, a physical random access channel (PRACH) resource for transmitting a preamble from multiple PRACH resources pre-configured by an eNB for the UE; and transmitting the preamble by the UE on a selected PRACH resource, so that the eNB transmits a random access response to UE to which a correctly demodulated preamble corresponds according to preambles transmitted by UEs. With the method and apparatus of the embodiments of the present invention, coverage performance of an uplink channel and a downlink channel may be improved.
1. A User equipment (UE), applicable to performing random access, the UE comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
randomly select a PRACH resource for transmitting a preamble from multiple PRACH resources pre-configured by an eNB for the UE; and
transmit the preamble on the selected PRACH resource, so that the eNB transmits a random access response to UE to which a correctly demodulated preamble corresponds according to preambles transmitted by UEs,
wherein, the multiple PRACH resources pre-configured by the eNB hop in a frequency domain within multiple transmission time,
wherein the processor is further configured to execute the instructions to:
calculate an RA-RNTI for performing CRC attachment on a PDCCH according to a PRACH resource occupied by the preamble; and
perform CRC de-attachment on a PDCCH according to the calculated RA-RNTI, so that the random access response is detected in a time window to which the preamble corresponds.
2. The UE according to claim 1 , wherein
the processor is configured to execute the instructions to:
receive UE-specific signaling transmitted by the eNB, the UE-specific signaling comprising time frequency position information of the multiple PRACH resources configured by the eNB for the UE.
3. An eNB, applicable to controlling random access, the eNB comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
configure multiple PRACH resources for all or part of UEs in a cell to which the eNB belongs, so that each of the UEs selects one of the multiple PRACH resources to transmit a preamble of its own;
demodulate and detect the preambles transmitted by the UEs in all possible PRACH resources configured for the UEs; and
transmit a random access response to UE to which a correctly demodulated preamble corresponds, wherein, the multiple PRACH resources configured by the eNB hop in a frequency domain within multiple transmission time,
wherein the processor is further configured to execute the instructions to:
calculate an RA-RNTI for performing CRC attachment on a PDCCH according to a PRACH resource used by a last combined preamble;
perform CRC attachment on a PDCCH by using the RA-RNTI; and
transmit the random access response by using a PDSCH scheduled by the PDCCH.
4. The eNB according to claim 3 , wherein the processor is configured to execute the instructions to:
group all or part of UEs in the cell to which the eNB belongs; and
allocate multiple PRACH resources for each group of UEs, so that the UE randomly selects one PRACH resource from the multiple PRACH resources to transmit the preamble of its own.
5. The eNB according to claim 3 , wherein the processor is further configured to execute the instructions to:
transmit UE-specific signaling to the UE, the UE-specific signaling comprising time frequency position information of multiple PRACH resources configured for the UE;
and wherein the multiple PRACH resources configured for each UE or each group of UEs are identical or different.
6. A User equipment (UE), applicable to performing random access, the UE comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
transmit multiple preambles within multiple transmission time, wherein PRACH resources used by the preambles hop in a frequency domain; and
detect a random access response in a time window to which each of the preambles corresponds, wherein the PRACH resources used by the preambles are pre-configured by an eNB, wherein the processor is further configured to execute the instructions to:
calculate an RA-RNTI for performing CRC attachment on a PDCCH according to a PRACH resource occupied by a last preamble in transmitted multiple preambles in the transmission time; and
perform CRC de-attachment on a PDCCH according to the calculated RA-RNTI, so that the random access response is detected in a time window to which each of the preambles corresponds.
7. The UE according to claim 6 , wherein the processor is further configured to execute the instructions to:
control to terminate transmission of subsequent preambles if a random access response is detected in a time window to which a preamble corresponds.
8. An eNB, applicable to controlling random access, the eNB comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
receive multiple preambles transmitted by UE within multiple transmission time, wherein PRACH resources used by the preambles hop in a frequency domain;
perform combined demodulation by using the received multiple preambles or a part of the multiple preambles; and
transmit a random access response to UE to which a correctly demodulated preamble corresponds, wherein the processor is further configured to execute the instructions to:
configure PRACH resources for transmitting preambles, so that the UE transmits the multiple preambles according to the PRACH resources configured by the eNB,
calculate an RA-RNTI for performing CRC attachment on a PDCCH according to a PRACH resource used by a last combined preamble;
perform CRC attachment on a PDCCH by using the RA-RNTI; and
transmit the random access response by using a PDSCH scheduled by the PDCCH.
9. The eNB according to claim 8 , wherein the processor is further configured to execute the instructions to:
transmit configuration signaling to the UE, the configuration signaling comprising time frequency position information of multiple PRACH resources configured for the UE and corresponding to the multiple preambles, and hopping manners of the multiple PRACH resources.
10. The eNB according to claim 8 , wherein the processor is further configured to execute the instructions to:
group all or part of the UEs in a cell to which the eNB belongs; and
configure identical PRACH resources for each group of UEs.
11. An eNB, applicable to controlling random access, the eNB comprising:
a memory that stores a plurality of instructions; and
a processor coupled to the memory and configured to execute the instructions to:
receive multiple preambles transmitted by UE within multiple transmission time, wherein PRACH resources used by the preambles hop in a frequency domain;
perform combined demodulation by using the received multiple preambles or a part of the multiple preambles; and
transmit a random access response to UE to which a correctly demodulated preamble corresponds, wherein the processor is configured to execute the instructions to:
calculate an RA-RNTI for performing CRC attachment on a PDCCH according to a PRACH resource used by a last combined preamble;
perform CRC attachment on a PDCCH by using the RA-RNTI; and
transmit the random access response by using a PDSCH scheduled by the PDCCH.