Radio-network node, wireless device and methods performed therein

A method performed by a wireless device operating in a wireless communication network, the method comprising:

• receiving configuration information from a radio network node, indicating a scheduled time-multiplexing arrangement of Physical Random Access Channels (PRACHs) within a corresponding PRACH subframe, each PRACH having a configured PRACH preamble length and a corresponding starting position within the PRACH subframe, the PRACHs being available for the wireless device to use when performing a random access procedure to the radio network node;
• selecting one of the PRACHs on the basis of the configured PRACH preamble lengths, in dependence on signal conditions at the wireless device relative to the radio network node;
• and
• initiating the random access procedure using the selected PRACH.

A non-transitory computer-readable storage medium, having stored thereon a computer program comprising instructions that, when executed on at least one processor of a radio network node, cause the radio network node to:

• dynamically configure Physical Random Access Channels (PRACHs) over recurring PRACH subframes, at least in terms of configured PRACH preamble lengths, based on at least one of a changing load on associated PRACH resources and changing signal conditions measured by or reported to the radio network node for a service area of the wireless communication network corresponding to the associated PRACH resources;
• and
• transmit configuration information indicating the configured PRACHs for respective ones of the recurring PRACH subframes;
• wherein the PRACHs configured for each of the recurring PRACH subframes represent a scheduled time-multiplexing arrangement of PRACHs of configured PRACH preamble lengths and corresponding starting positions within the PRACH subframe.

A non-transitory computer-readable storage medium, having stored thereon a computer program comprising instructions that, when executed on at least one processor of a wireless device, cause the wireless device to:

• receive configuration information from a radio network node in a wireless communication network, indicating a scheduled time-multiplexing arrangement of Physical Random Access Channels (PRACHs) within a corresponding PRACH subframe, each PRACH having a configured PRACH preamble length and a corresponding starting position within the PRACH subframe, the PRACHs being available for the wireless device to use when performing a random access procedure to the radio network node;
• select one of the PRACHs on the basis of the configured PRACH preamble lengths, in dependence on signal conditions at the wireless device relative to the radio network node;
• and
• initiate the random access procedure using the selected PRACH.

A radio-network node configured for operation in a wireless communication network, the radio network node comprising:

• communication circuitry configured for communicating with wireless devices operating in a service area associated with the radio network node;
• and
• processing circuitry operatively associated with the communication circuitry and configured to:
• dynamically configure Physical Random Access Channels (PRACHs) over recurring PRACH subframes, at least in terms of configured PRACH preamble lengths, based on at least one of a changing load on associated PRACH resources and changing signal conditions measured by or reported to the radio network node for a service area of the wireless communication network corresponding to the associated PRACH resources;
• and
• transmit configuration information indicating the configured PRACHs for respective ones of the recurring PRACH subframes;
• wherein the PRACHs configured for each of the recurring PRACH subframes represent a scheduled time-multiplexing arrangement of PRACHs of configured PRACH preamble lengths and corresponding starting positions within the PRACH subframe.

A wireless device configured for operation in a wireless communication network, the wireless device comprising:

• communication circuitry configured for communicating with a radio network node in the wireless communication network;
• and
• processing circuitry operatively associated with the communication circuitry and configured to:
• receive configuration information from the radio network node, indicating a scheduled time-multiplexing arrangement of Physical Random Access Channels (PRACHs) within a corresponding PRACH subframe, each PRACH having a configured PRACH preamble length and a corresponding starting position within the PRACH subframe, the PRACHs being available for the wireless device to use when performing a random access procedure to the radio network node;
• select one of the PRACHs on the basis of the configured PRACH preamble lengths, in dependence on signal conditions at the wireless device relative to the radio network node;
• and
• initiate the random access procedure using the selected PRACH.