Wireless Signal Transmission Using Variable OFDM Symbol Lengths
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Solution Overview
Problem
Millimeter wave communication systems face challenges in reducing system overhead due to the large number of reference signals required for beam acquisition, which decreases overall system capacity and antenna gain.
Innovation Solution
The method involves configuring different OFDM symbol lengths for data and reference signals based on communication characteristics, such as user terminal velocities and environments, to minimize the number of reference signals needed for beamforming, thereby reducing system overhead and increasing antenna gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of reference signals is increased to improve beam acquisition performance, then beamforming accuracy is improved, but system overhead increases and system capacity decreases
Solution Approach 1:
The patent segments the reference signal transmission into two distinct phases: initial beam acquisition phase requiring comprehensive beam coverage, and subsequent data transmission phase using established beams. This segmentation allows the system to use more reference signals only when necessary for beam selection, rather than continuously, thereby reducing overall system overhead while maintaining beam acquisition performance.
Solution Approach 2:
The patent implements periodic beam refinement where the system transitions from frequent reference signal transmission during beam acquisition to less frequent transmission during stable communication. Beam refinement protocols are triggered periodically or based on event conditions (such as beam quality degradation), allowing the system to maintain accurate beamforming while reducing reference signal overhead during stable operation periods.
2Length of stationary object
If beamforming is applied to mitigate propagation path loss, then propagation distance is increased, but system overhead increases due to beam management requirements
Solution Approach 1:
The patent performs preliminary beam acquisition and refinement before actual data transmission begins. During this preliminary phase, the system establishes optimal transmit and receive beams using reference signals and feedback mechanisms. Once beams are established, the system maintains propagation distance benefits while reducing overhead by relying on the pre-configured beam directions rather than continuously managing beams during data transmission.
Solution Approach 2:
The patent implements self-service beam maintenance where the system uses implicit feedback from received signal quality to automatically adjust and maintain beam directions without requiring explicit beam management signaling. The receiver monitors signal quality and triggers beam refinement only when necessary, allowing the beamforming system to maintain propagation distance benefits while minimizing the overhead associated with continuous beam management.
Data Source
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AI summary
An apparatus and method for transmitting a signal needed for beam acquisition in a wireless communication system operating in a super-high frequency band are provided, in which a small reference modulation symbol length relative to a data modulation symbol length is determined, taking into account a communication characteristic of a Mobile Station (MS), a data modulation symbol generated by modulating a data signal using a predetermined modulation scheme is transmitted according to the determined data modulation symbol length, and a reference modulation symbol generated by modulating a reference signal using the predetermined modulation scheme is transmitted according to the determined reference modulation symbol length.