# US 8,570,902 B2 · Method and terminal for selecting random access resource > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,902 B2 - Document ID: US8570902B2 - Status: Granted - Kind: B2 - Application number: 13/203,446 - Filed: 2009-09-25 - Published: 2012-03-15 - Granted: 2013-10-29 - Earliest claimed: 2009-03-16 - Assignees: Zte Corporation - Applicants: Zhongda Du; Rui Ma; Bin Yu - Inventors: Zhongda Du; Rui Ma; Bin Yu - Web page: https://patentgrep.com/patent/US8570902B2 ## CPC - H04W 74/002: {Transmission of channel access control information} - H04W 36/0077: {of access information of target access point} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract 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. ## Claims ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 2) The method according to claim 2, wherein k is equal to 6 milliseconds. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 4) 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. ### Claim 6 (depends on 5) The method according to claim 5, wherein k is equal to 6 milliseconds. ### Claim 7 (depends on 4) The method according to claim 4, wherein k is equal to 6 milliseconds. ### Claim 8 (depends on 1) The method according to claim 1, wherein k is equal to 6 milliseconds. ### Claim 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. ### Claim 10 (depends on 9) 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. ### Claim 11 (depends on 10) 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. ### Claim 12 (depends on 11) 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. ### Claim 13 (depends on 9) 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. ### Claim 14 (depends on 13) 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. ### Claim 15 (depends on 14) 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.