Random access preamble design

A mobile communications system, comprising a user equipment (UE) in communication with a base station (BS) via a cell of the mobile communications system, wherein

• the UE is configured to:
• select a random access preamble sequence from a set of random access preamble sequences;
• and
• transmit the random access preamble sequence to the BS;
• and
• the BS is configured to:
• receive the random access preamble sequence;
• and
• estimate a time of arrival of the random access preamble sequence, wherein the set of random access preamble sequences is included in 64 random access preamble sequences available in the cell, the 64 random access preamble sequences are obtained from at least one Zadoff-Chu sequence, the at least one Zadoff-Chu sequence is used in generation of a sequence xu,v(k) for the 64 random access preamble sequences, xu,v(k) is given by:
• xu,v(k)=xu,v((k+vNCS) mod NZC), where u and v are integers, NZC is a length of the at least one Zadoff-Chu sequence, NCS is given by a pre-defined set including all of the following values:
• 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419, and
• Zadoff-Chu sequence is defined by:
• xj(k)=Wuk(k+1)/2, k=0,1, . . . , NZC−1, W=e−j2π/NZC, j=√{square root over (−1)}.

A user equipment (UE), comprising:

• a memory retaining instructions related to:
• selecting a random access preamble sequence from a set of random access preamble sequences;
• and
• transmitting the random access preamble sequence to a base station (BS), the UE being used for communicating with the BS via a cell of a mobile communications system;
• wherein the set of random access preamble sequences is included in 64 random access preamble sequences available in the cell, the 64 random access preamble sequences are obtained from at least one Zadoff-Chu sequence, the at least one Zadoff-Chu sequence is used in generation of a sequence xu,v(k) for the 64 random access preamble sequences, xu,v(k) is given by:
• xu,v(k)=xu,v((k+vNCS) mod NZC), where u and v are integers, NZC is a length of the at least one Zadoff-Chu sequence, NCS is given by a pre-defined set including all of the following values:
• 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419, and
• Zadoff-Chu sequence is defined by:
• xu(k)=Wuk(k+1)/2, k=0,1, . . . , NZC−1, W=e−j2π/NZC, j=√{square root over (−1)};
• and
• a processor, coupled to the memory, configured to execute the instructions retained in the memory.

A base station (BS), comprising:

• a memory retaining instructions related to:
• receiving a random access preamble sequence, the random access preamble sequence being selected from a set of random access preamble sequences;
• and
• estimating a time of arrival of the random access preamble sequence, the BS being used for communicating with a user equipment (UE) via a cell of a mobile communications system;
• wherein the set of random access preamble sequences is included in 64 RAPs available in the cell, the 64 random access preamble sequences are obtained from at least one Zadoff-Chu sequence, the at least one Zadoff-Chu sequence is used in generation of a sequence xu,v(k) for the 64 random access preamble sequences, xu,v(k) is given by:
• xu,v(k)=xu,v((k+vNCS) mod NZC), where u and v are integers, NZC is a length of the at least one Zadoff-Chu sequence, NCS is given by a pre-defined set including all of the following values:
• 0, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 93, 119, 167, 279, 419, and
• Zadoff-Chu sequence is defined by:
• xu(k)=Wuk(k+1)/2, k=0,1, . . . , NZC−1, W=e−j2π/NZC, j=√{square root over (−1)};
• and
• a processor, coupled to the memory, configured to execute the instructions retained in the memory.