Extended Cyclic Prefix for 5G NR Radio Frames
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Solution Overview
Problem
The 5G NR standard's limited cyclic prefix size in certain configurations leads to inter-symbol interference and signal degradation, particularly in broadcast/multicast and cooperative relaying applications due to excessive time differences between signal multi-paths.
Innovation Solution
Increasing the size of cyclic prefixes and suffixes in radio frames, while maintaining the same number of useful symbols, to enhance resistance to multi-paths and synchronization imperfections, thereby extending the duration of radio half-slots by 1.5 times the standard duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cyclic prefix size is increased to reduce inter-symbol interference in multipath propagation, then signal reliability improves, but radio frame duration increases
Solution Approach 1:
The patent implements dynamic cyclic prefix configuration by introducing multiple CP length options (standard CP and extended CP) that can be selected based on propagation conditions. The extended CP is activated specifically for broadcast/multicast and cooperative relaying scenarios where multipath delay spread exceeds standard CP coverage, allowing the system to adaptively adjust CP duration to match actual channel conditions rather than using a fixed duration.
Solution Approach 2:
The patent changes the cyclic prefix duration parameter from a fixed standard value to variable values (standard CP and extended CP). This parameter change enables the system to handle time gaps between multipaths exceeding the original CP size by switching to extended CP configurations, thereby improving signal reliability in challenging propagation environments while maintaining backward compatibility with standard configurations.
2Reliability
If the cyclic prefix size is increased to accommodate larger time gaps between multipaths, then resistance to multipath propagation improves, but transmission time increases
Solution Approach 1:
The system dynamically selects between standard and extended cyclic prefix configurations based on the detected multipath time gap characteristics. Extended CP is deployed only when time gaps between multipaths exceed standard CP coverage, avoiding unnecessary transmission time expansion in scenarios where standard CP suffices, thus optimizing the trade-off between multipath resistance and transmission efficiency.
Solution Approach 2:
The patent modifies the cyclic prefix duration parameter to extended values specifically for broadcast/multicast and cooperative relaying applications where large time gaps between multipaths are expected. This parameter change enables the system to achieve improved multipath resistance only when required by propagation conditions, minimizing unnecessary transmission time loss in other scenarios.
3Reliability
If extended cyclic prefix is implemented for broadcast/multicast applications, then signal-to-noise ratio is maintained, but frame structure complexity increases
Solution Approach 1:
The patent implements dynamic frame structure configuration by introducing extended cyclic prefix modes that can be activated based on application type and propagation conditions. The frame structure adapts between standard and extended CP configurations, allowing SNR maintenance in broadcast/multicast scenarios with large multipath time gaps while avoiding unnecessary structural complexity in standard unicast communications.
Solution Approach 2:
The patent changes frame structure parameters by introducing extended cyclic prefix configurations specifically for broadcast/multicast and cooperative relaying applications. This parameter modification enables SNR maintenance in challenging propagation environments while maintaining backward compatibility with standard frame structures for conventional applications, thus managing complexity through selective parameter adaptation.
Data Source
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AI summary
A radio frame transmission method (301) consisting of: for any spacing Δf between frequency subcarriers, a determined number of samples N per useful OFDM symbol and a determined transmission frequency band, where said spacing Δf, number of samples N per useful OFDM symbol and transmission frequency band BW are such as prescribed by the 3GPP 5G NR standard and define a current transmission configuration, generating useful OFDM symbols; constructing a radio frame in which each useful OFDM symbol is preceded by a cyclic prefix repeating a part of said useful OFDM symbol.It is characterized in that the total number of useful OFDM symbols in a radio half-slot associated with the radio frame is equal to the number prescribed by the 3GPP 5G NR standard for said configuration and in that a duration of the radio half-slot is increased so as to be able to accommodate said number of useful OFDM symbols while also increasing the size of the cyclic prefixes added to the useful OFDM symbols compared to the size of the cyclic prefixes prescribed by said 3GPP 5G NR standard for said configuration.