Cyclic Prefix Design for Wireless Subframe Timing Overlap
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems using OFDMA or analogous radio access schemes, adjusting transmission timing can lead to packet collisions and deterioration in reception performance due to delay spread and timing misalignment, increasing reception complexity.
Innovation Solution
A method of adjusting transmission timing by creating a cyclic prefix (CP) that considers the overlap with the previous symbol, allowing for the advancement of subframe start timing and removal of overlapping parts from the CP, thereby minimizing interference and maintaining reception performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission timing is adjusted to advance subframe start timing for continuous packet transmission, then productivity is improved, but packet collisions occur and reception performance deteriorates
Solution Approach 1:
The transmitting side creates a cyclic prefix (CP) in advance that considers the overlap with the previous symbol before transmission timing adjustment is applied. This preliminary preparation of the CP structure ensures that when timing advancement occurs, the overlapping portions are already accounted for in the CP design, preventing packet collisions and maintaining reception performance.
Solution Approach 2:
The invention applies preliminary anti-action by designing the cyclic prefix to preemptively counteract the harmful effects of timing overlap. By considering the overlap with the previous symbol during CP creation, the system pre-compensates for the interference that would otherwise occur during timing-adjusted continuous transmission, thus preventing reception performance deterioration.
2Loss of time
If transmission timing is adjusted to advance subframe start timing, then loss of time is reduced, but device complexity increases due to overlap management
Solution Approach 1:
The cyclic prefix is created in advance with consideration for the overlap with the previous symbol, before the timing adjustment is actually applied. This preliminary structuring of the CP simplifies the reception process by pre-organizing the signal structure to accommodate timing advancements, thereby reducing the complexity that would otherwise arise from managing overlaps in real-time.
Solution Approach 2:
The invention changes the parameter of the cyclic prefix by creating it in consideration of the overlap with the previous symbol. This parameter modification allows the system to advance subframe start timing without increasing reception complexity, as the CP structure is already adapted to the timing adjustment rather than requiring complex real-time overlap management.
3Ease of manufacture
If cyclic prefix is created without considering overlap with previous symbol, then ease of manufacture is improved, but inter-symbol interference increases
Solution Approach 1:
The invention modifies the cyclic prefix parameter by creating it in consideration of the overlap with the previous symbol. This parameter change maintains the simplicity of the signal processing approach while effectively reducing inter-symbol interference, as the CP structure is adapted to account for the timing overlap without requiring complex processing.
Solution Approach 2:
The invention converts the potentially harmful overlap between symbols into a beneficial structure by incorporating the overlap consideration into the cyclic prefix creation. Instead of treating the overlap as interference to be eliminated through complex means, the system uses the overlap information to shape the CP, thereby reducing inter-symbol interference while maintaining processing simplicity.
Data Source
AI summary
A method of a user equipment (UE) operating in a wireless communication system using orthogonal subcarriers, the method including generating, by the UE, Orthogonal Frequency Division Multiplexing (OFDM)-based symbols, wherein each OFDM-based symbol includes a cyclic prefix (CP) and a data part, transmitting, by the UE, a first subframe including N OFDM-based symbols, wherein N is an integer and transmitting, by the UE, a second subframe including N OFDM-based symbols, following the first subframe, wherein, when the first subframe and the second subframe are overlapped based on a timing adjustment command received from a base station, the first subframe is transmitted completely while the second subframe is transmitted partially without an overlapped part of the second subframe.