Random Access Mode Control Method and Entity

A network entity for communicating with terminals in a cell of a cellular communication system, said cell adapted for operating in a first random access mode associated with a first set of random access identification sequences or in a second random access mode associated with a second set of random access identification sequences, said random access identification sequences to be used by terminals performing a random access operation in said cell, where said second set of random access identification sequences is arranged for avoiding misidentifications due to sequence alterations occurring in transmissions from said terminals, the network entity comprising

• a random access identification sequence detector,
• an analyser for performing a sequence alteration analysis based on an output of the random access identification sequence detector, and
• a mode switch adapted to automatically switch operation of said cell from one of said random access modes to the other of said random access modes if a mode switching condition is determined on the basis of the sequence alteration analysis.

A method in a cellular communication system for controlling a random access mode in a cell of a cellular communication system, said cell being operable in a first random access mode associated with a first set of random access identification sequences or in a second random access mode associated with a second set of random access identification sequences, said random access identification sequences to be used by terminals performing a random access operation in said cell, where said second set of random access identification sequences is arranged for avoiding misidentifications due to sequence alterations occurring in transmissions from said terminals, the cellular communication system comprising a first network entity and a second network entity, the method comprising:

• the first network entity, performing a sequence alteration analysis based on an output of a random access identification sequence detector in the first network entity, and
• the second network entity, if a mode switching condition is determined on the basis of the sequence alteration analysis, automatically switching operation of said cell from one of said random access modes to the other of said random access modes.