5G NR Radio Frame Cyclic Prefix Extension for Multi-path Interference
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Solution Overview
Problem
The 5G NR standard's limitations in handling multi-path interference and synchronization imperfections, particularly in broadcast/multicast and cooperative relaying applications, due to the Extended Cyclic Prefix not being authorized for certain configurations, lead to significant signal interference and drop in signal-to-noise ratio.
Innovation Solution
The method involves reducing the number of OFDM symbols in a radio frame to increase the size of cyclic prefixes and suffixes, enhancing the frame's resistance to multi-paths and synchronization imperfections, while maintaining compatibility with the 5G NR standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of OFDM symbols in a radio frame is reduced to increase cyclic prefix size, then resistance to multi-path interference is improved, but the total number of useful symbols transmitted is reduced
Solution Approach 1:
The patent changes the parameter of cyclic prefix length from the standard configuration to an extended configuration. By increasing the cyclic prefix length beyond what is prescribed by the 3GPP 5G NR standard for certain subcarrier spacings, the system achieves better resistance to multi-path interference and synchronization imperfections, particularly for broadcast/multicast and cooperative relaying applications.
Solution Approach 2:
The patent applies partial action by selectively extending the cyclic prefix only for specific applications (broadcast/multicast and cooperative relaying) rather than for all transmissions. This is achieved by configuring certain radio frames with extended cyclic prefixes while maintaining standard configurations for other traffic types, thus optimizing performance for specific use cases without universally impacting system throughput.
2Reliability
If the cyclic prefix size is increased to handle synchronization imperfections, then signal quality is improved, but the duration of each OFDM symbol increases
Solution Approach 1:
The patent modifies the cyclic prefix parameter to be longer than the standard configuration, which directly improves signal quality by better handling synchronization imperfections and multi-path effects. The extended cyclic prefix acts as a more effective guard interval, allowing the system to tolerate larger timing offsets and multipath delays.
Solution Approach 2:
The extended cyclic prefix serves as a pre-configured cushion or buffer that protects against synchronization errors and multi-path interference before they affect the useful symbol. By having a longer guard interval in place beforehand, the system is preemptively protected against timing mismatches and reflected signals.
Data Source
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AI summary
This process, carried out by an electronic radio transmission module (10), consists of: for any spacing Δf between frequency subcarriers previously selected from several spacings, a determined number of samples N per useful OFDM symbol and a determined transmission frequency band BW where said spacing Δf, number of samples N per symbol and transmission frequency band BW are such as prescribed by the 3GPP 5G NR standard and defining a current transmission configuration, generating useful OFDM symbols; constructing a radio frame of duration 10 ms comprising some of the generated useful OFDM symbols and in which each useful OFDM symbol is preceded by a cyclic prefix, respectively followed by a cyclic suffix, repeating a part of said useful symbol.It is characterized in that the total number of useful OFDM symbols in the radio frame is strictly less than the number prescribed by the 3GPP 5G NR standard for said configuration and in that the resource thus freed in the radio frame is used by increasing the size of the cyclic prefixes, respectively suffixes, of said symbols compared to the size of the prefixes prescribed for said configuration by said standard.