Coherent detection of large physical random access control channel (prach) delays
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsJohan AXNÄS, Henrik SAHLIN, Andres REIAL, Naga Vishnu Kanth IRUKULAPATI
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Abstract
According to embodiments described herein, a long delay-detector improves delay estimation performance for PRACH for many practical deployment scenarios. This, for example, reduces the risk that the timing advance of the UE is set incorrectly and hence reduces the risk that subsequent communication fails and that the UE spreads unnecessary interference to other communication in the system.
Claims27
A method in a radio network node for processing a preamble used in a wireless communication system, the method comprising:
- receiving, from a user equipment (UE), the preamble including a plurality of short sequences;
- determining, by a preamble detector, a fractional-symbol delay (Tfrac) of at least one of the plurality of short sequences;
- and
- based at least in part on the determined Tfrac, using at least one of a first part of the preamble detector, the first part used to detect portions of the preamble arriving during an early time window of the plurality of time windows, and a second part of the preamble detector, the second part used to detect portions of the preamble arriving during a late time window of the plurality of time windows, to process at least one short sequence of the plurality of short sequences as part of calculating a propagation delay between the UE and the radio network node.
A method in a user equipment (UE) for transmitting a preamble, wherein the preamble is comprised of a plurality of short sequences, the method comprising:
- transmitting, by the UE, the preamble to a radio network node, the transmitting including changing a transmission characteristic part way through the transmission of the preamble to split the preamble into two portions, wherein the transmitting includes:
- transmitting a first of the two portions of the preamble using a first transmission characteristic;
- and
- transmitting a second of the two portions of the preamble using a second transmission characteristic that is different from the first transmission characteristic.
A method in a radio network node for processing a preamble, the method comprising:
- detecting a change in a transmission characteristic of a preamble received from a user equipment (UE) part way through receiving the preamble, the change in transmission characteristic splitting the preamble into two portions, wherein the preamble includes a plurality of short sequences;
- and
- determining, based on the two portions of the preamble, a propagation delay between the radio network node and the UE.
-55. (canceled)
Dependencies are inferred from the claim text.