Mobile Node Specific Cyclic Prefix for Delay Spread Adaptation
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Solution Overview
Problem
Current mobile communication systems use fixed cyclic prefixes based on pre-configured settings, which do not adapt to varying delay spreads caused by different propagation environments and mobile node positions, leading to inefficient resource allocation and reduced bit rates.
Innovation Solution
A method where a base station performs uplink direction delay spread measurements and selects a cyclic prefix length specific to each mobile node, allowing for dynamic adjustment of cyclic prefix lengths based on actual delay spread conditions, enabling more efficient data transmission by optimizing cyclic prefix usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extended cyclic prefix is used to handle large delay spread, then signal reliability is improved, but transmission bit rate decreases
Solution Approach 1:
The patent implements dynamic cyclic prefix configuration where the base station determines the actual delay spread for each mobile node through measurements and selects appropriate cyclic prefix lengths accordingly. This dynamic adaptation allows the system to use extended cyclic prefix only when necessary for signal reliability, while using normal cyclic prefix in other cases to maintain higher transmission bit rates, thus resolving the contradiction between reliability and productivity
Solution Approach 2:
The patent applies different cyclic prefix configurations to different mobile nodes based on their local propagation conditions. Instead of uniformly applying extended cyclic prefix to all nodes in a cell, each mobile node receives a customized cyclic prefix setting matched to its specific delay spread characteristics, optimizing both reliability for that node and overall system bit rate
2Productivity
If normal cyclic prefix is used to maximize bit rate, then transmission efficiency is improved, but signal reliability deteriorates in high delay spread environments
Solution Approach 1:
The base station dynamically determines appropriate cyclic prefix lengths by measuring actual delay spread for each mobile node and selecting between normal and extended cyclic prefix configurations based on these measurements. This dynamic approach ensures normal cyclic prefix is used to maximize bit rate when delay spread is small, while automatically switching to extended cyclic prefix when delay spread requires it for reliability
Solution Approach 2:
The patent changes the cyclic prefix length parameter based on measured delay spread conditions. The base station measures delay spread and adjusts the cyclic prefix parameter accordingly, selecting normal cyclic prefix (shorter length) for low delay spread scenarios to maximize bit rate, and extended cyclic prefix (longer length) for high delay spread scenarios to ensure signal reliability
3Device complexity
If cell-based fixed cyclic prefix configuration is used, then system complexity is reduced, but adaptability to varying propagation environments deteriorates
Solution Approach 1:
The base station performs self-service by automatically measuring delay spread for each mobile node and determining appropriate cyclic prefix configurations without manual intervention. This self-service mechanism maintains relatively simple system operation while achieving mobile-node-specific adaptation to varying propagation environments within the cell
Solution Approach 2:
The patent introduces dynamic cyclic prefix configuration that adapts to varying propagation environments by measuring actual delay spread conditions for each mobile node. This dynamic approach significantly improves adaptability compared to fixed cell-based configuration, while the automation of measurements and selections keeps the increase in system complexity manageable
Data Source
AI summary
The invention concerns a method and an apparatus implementing the method. In the method is determined in a mobile node whether the mobile node supports mobile node specific cyclic prefixes. The mobile node transmits to a base station node an indication whether the mobile node supports mobile node specific cyclic prefixes. The base station node measures a delay spread of a radio resource transmitted by the mobile node. The mobile node receives an indication of an uplink direction cyclic prefix length from the base station node. The mobile node forms a cyclic prefix of the uplink direction cyclic prefix length selected from a useful symbol, adds the cyclic prefix in front of the useful symbol and transmits a signal comprising the cyclic prefix and the useful symbol to the base station.