Terrestrial Node Location Calculation for NTN Timing Advance
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Solution Overview
Problem
The use of non-terrestrial network (NTN) nodes in wireless communication systems results in significant signal transmission propagation delays, leading to inter-symbol interference and the inability of terrestrial network solutions to correct timing errors effectively due to propagation delays exceeding cyclic prefix lengths, necessitating an accurate and efficient method for determining communication and signaling offsets between user equipment and NTN nodes.
Innovation Solution
An apparatus and method for evaluating the location of a terrestrial network node by receiving propagation delay and location indications, using broadcast system information blocks and ephemeris information to calculate the NTN node's location, allowing for precise determination of timing advances and reducing the need for frequent SIB readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terrestrial network timing advance correction is used, then timing errors can be corrected within cyclic prefix length, but propagation delay exceeds cyclic prefix length making correction ineffective
Solution Approach 1:
The patent applies preliminary action by having the network node pre-calculate and provide timing advance values to multiple terrestrial network nodes before actual communication occurs. The location evaluation apparatus determines the locations of terrestrial network nodes in advance, and the network node uses these pre-determined timing advance values to correct timing errors before uplink transmissions occur, making the correction effective despite large propagation delays.
2Ease of operation
If a common timing advance value is used for all UE devices, then network operation is simplified, but different transmission delays occur for different UE locations within the large footprint
Solution Approach 1:
The patent applies local quality by providing different timing advance values to different terrestrial network nodes based on their specific locations. The location evaluation apparatus evaluates the location of each terrestrial network node individually, and the network node transmits different timing advance values corresponding to each node's location. This ensures that each UE device receives a timing advance value appropriate for its specific geographic position within the large footprint, maintaining both operational simplicity and correction precision.
3Measurement precision
If frequent SIB readings are performed to maintain accurate timing information, then timing accuracy is improved, but operational overhead and power consumption increase
Solution Approach 1:
The patent applies preliminary action by having the network node provide timing advance values proactively to terrestrial network nodes in advance, eliminating the need for frequent SIB readings. The location evaluation apparatus determines locations and calculates timing advance values beforehand, and the network node transmits these pre-calculated values directly to the appropriate nodes. This preliminary provision of timing information maintains accuracy while significantly reducing operational overhead and power consumption associated with frequent broadcasting and reading operations.
Data Source
AI summary
Aspects and embodiments relate to an apparatus and method for evaluating location of a terrestrial network node in a non-terrestrial network. In particular, one aspect provides an apparatus, comprising means for receiving an indication of propagation delay between a terrestrial network node and a non-terrestrial node in a non-terrestrial wireless communication network; means for receiving an indication of location of the non-terrestrial node; and means for evaluating location of the terrestrial network node in dependence upon the received indication of propagation delay between the terrestrial network node and the non-terrestrial node, and the indication of location of the non-terrestrial node. A further aspect provides a method of evaluating location of a terrestrial network node, and a computer program product operable, when executed on a computer, to perform that method. Aspects and embodiments recognise that having a knowledge of gNB and NTN-GW location in a non-terrestrial network can allow UE to simplify procedures in relation to the updating and tracking of forward link delay. Since it has been agreed that a network will not directly provide the gNB and/or NTN-GW location to UE, due to security and privacy reasons in some countries, apparatus can be configured to perform methods according to which a UE is operable to calculate or obtain information which can assist its ongoing operation and reduce an ongoing need to decode SIB in support of calculation of an appropriate Uplink timing advance (TA) to apply in relation to communications exchanged with a network.