Method and terminal for selecting random access resource
The present invention discloses a method and terminal for selecting a random access resource, the method includes: the terminal receives the physical downlink control channel signaling sent by a system; the terminal determines the first subframe which meets a condition A and contains a random access resource from the subsequent subframes of the subframe receiving the physical downlink control channel signaling, the condition A is that the time difference between the first subframe and the subframe receiving the physical downlink control channel signaling is greater than or equal to k, k is the time delay defined by the physical layer of the terminal; and the terminal starts a selection on the subframe containing a random access source from the first subframe.
1. A method for selecting a random access resource, the method comprising:
receiving, by a terminal, a physical downlink control channel signaling sent by a system;
determining, by the terminal, from among a plurality of subframes following a subframe in which the physical downlink control channel signaling is received, a first subframe which meets condition A and contains a random access resource, wherein
condition A is that the time difference between the current subframe and the subframe in which the physical downlink control channel signaling is received is greater than or equal to k, and k is a time delay defined at a physical layer of the terminal; and
selecting, by the terminal, starting from the first subframe, one or more subframes each containing a respective random access source,
wherein assuming the subframe in which the physical downlink control channel signaling is received has a subframe number m, and is located in a radio frame which has a frame number M, the first subframe has a subframe number n, and is located in a radio frame which has a frame number N, the first subframe further meets the following equation:
N= ( M +└( m+k )/10┘)%1024, n= ( m+k )%10.
2. The method according to claim 1 , wherein
a Physical Random Access Channel (PRACH) mask index and a physical random access preamble index are included in the physical downlink control channel signaling;
the first subframe containing the random access resource is determined by a PRACH configuration index, the PRACH mask index and the physical random access preamble index, wherein the PRACH configuration index is acquired by the terminal from a system message or a handover signaling; and
the range for the selection on the subframe containing a random access resource is the first subframe.
3. The method according to claim 2 , wherein k is equal to 6 milliseconds.
4. The method according to claim 1 , wherein
a PRACH mask index and a physical random access preamble index are included in the physical downlink control channel signaling; and
the subframe containing a random access resource is determined by a PRACH configuration index, the PRACH mask index, the physical random access preamble index and an uplink/downlink configuration index, wherein the PRACH configuration index and the uplink/downlink configuration index are acquired by the terminal from a system message or a handover signaling.
5. The method according to claim 4 , wherein
when the PRACH mask index is not equal to 0, the time range for the terminal to select the subframe containing a random access resource is the first subframe; and
when the PRACH mask index is equal to 0, the time range for the terminal to select the subframe containing a random access resource is the first subframe and two successive subframes subsequent to the first subframe.
6. The method according to claim 5 , wherein k is equal to 6 milliseconds.
7. The method according to claim 4 , wherein k is equal to 6 milliseconds.
8. The method according to claim 1 , wherein k is equal to 6 milliseconds.
9. A terminal for selecting a random access resource, the terminal comprising: a memory storing instructions for a receiving module, a subframe selecting module and a resource selecting module, wherein
a processor executing the stored instructions for the receiving module receives a physical downlink control channel signaling sent by a system;
said processor executing the stored instructions for the subframe selecting module determines from among a plurality of subframes following a subframe in which the physical downlink control channel signaling is received, a first subframe which meets condition A and contains a random access resource, wherein condition A is that the time difference between the current subframe and the subframe in which the physical downlink control channel signaling is received is greater than or equal to k, and k is the time delay defined at a physical layer of the terminal; and
said processor executing the stored instructions for the resource selecting modules selects, starting from the first subframe, one or more subframes each containing a respective random access source,
wherein assuming the subframe in which the physical downlink control channel signaling is received has a subframe number m, and is located in a radio frame which has a frame number M, the first subframe has a subframe number n, and is located in a radio frame which has a frame number N, the first subframe further meets the following equation:
N= ( M +└( m+k )/10┘)%1024, n= ( m+k )%10.
10. The terminal according to claim 9 , wherein
a PRACH mask index and a physical random access preamble index are included in the physical downlink control channel signaling; and
said processor executing the stored instructions for the receiving module further receives a system message or handover signaling which includes a PRACH configuration index.
11. The terminal according to claim 10 , further comprising a storage, wherein
the storage is arranged for storing a PRACH configuration table and a PRACH mask index table; and
wherein the memory further stores instructions for an analyzing module, and said processor executing the stored instructions for the analyzing module determines the subframe containing a random access resource according to the physical downlink control channel signaling, the system message or handover signaling, and the storing module.
12. The terminal according to claim 11 , wherein
the first subframe is selected from the subframes containing a random access resource; and
the range for the resource selecting module to select the subframe containing a random access resource is the first subframe.
13. The terminal according to claim 9 , wherein
a physical random access preamble index and a PRACH mask index are included in the physical downlink control channel signaling; and
said processor executing the stored instructions for the receiving module further receives a system message or handover signaling which includes a PRACH configuration index and an uplink/downlink configuration index.
14. The terminal according to claim 13 , further comprising a storage, wherein
the storage is arranged for storing a PRACH configuration table and a PRACH mask index table; and
wherein the memory further stores instructions for an analyzing module, and said processor executing the stored instructions for the analyzing module determines the subframe containing a random access resource according to the physical downlink control channel signaling, the system message or handover signaling, and the storing module.
15. The terminal according to claim 14 , wherein
the first subframe is selected from the subframes containing a random access resource;
when the PRACH mask index is not equal to 0, the time range for the resource selecting module to select the subframe containing a random access resource is the first subframe; and
when the PRACH mask index is equal to 0, the time range for the resource selecting module to select the subframe containing a random access resource is the first subframe and two successive subframes subsequent to the first subframe.