NR Control Allocation in LTE Downlink Symbol 1
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Solution Overview
Problem
The integration of NR and LTE in shared spectrum downlink transmissions is constrained by limited NR control channel capacity due to LTE CRS, leading to inefficient spectrum use and compromised throughput performance.
Innovation Solution
Allocate the symbol at index 1 in the LTE downlink subframe for NR control information, mute LTE transmission in this symbol, and configure resource elements for NR transmission, while compensating LTE user equipment for performance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTE CRS is transmitted in the first two symbols with 4 CRS port configuration, then LTE reliability is maintained, but NR control channel capacity is constrained to only 1 symbol
Solution Approach 1:
The patent makes the CRS port configuration dynamic by allowing the network to switch between 2 CRS port configuration and 4 CRS port configuration based on traffic conditions. When NR control channel capacity is needed, the system uses 2 CRS port configuration to free up symbol 1 for NR control information. When LTE performance is prioritized, it switches to 4 CRS port configuration. This dynamic adaptation resolves the contradiction by making the system flexible rather than fixed.
Solution Approach 2:
The patent changes the CRS port configuration parameter (from 2 to 4 ports) to adjust the balance between LTE reliability and NR control channel capacity. By modifying this key parameter, the system can adapt to different operational requirements and resolve the resource allocation conflict between the two technologies.
2Quantity of substance
If 2 CRS port configuration is used to enable NR control information in symbol 1, then NR control channel capacity increases, but LTE throughput performance deteriorates above 1 GHz
Solution Approach 1:
The system dynamically selects between 2 CRS port and 4 CRS port configurations based on real-time conditions including frequency band, traffic requirements, and user equipment capabilities. This dynamic selection allows the system to optimize for either NR control capacity or LTE throughput depending on current needs, rather than being locked into a single configuration.
Solution Approach 2:
The patent segments the control channel resources by allocating different symbols to LTE and NR control information based on the CRS port configuration. In 2 CRS port mode, symbol 1 is segmented for NR control information while symbol 0 remains for LTE. This segmentation allows both technologies to coexist with appropriate resource allocation.
3Quantity of substance
If advanced user equipment capabilities are required to decode PDSCH type B, then NR control channel capacity increases, but device complexity and cost increase significantly
Solution Approach 1:
Instead of requiring user equipment to implement complex PDSCH type B decoding capabilities, the patent uses a simpler approach by configuring different CRS port patterns that user equipment can handle with existing capabilities. The network side performs the complex resource allocation and mapping, while user equipment only needs to follow standard decoding procedures with the configured parameters.
Solution Approach 2:
The patent introduces CRS port configuration as an intermediary mechanism that enables NR control channel capacity increase without requiring direct changes to user equipment complexity. The network configures appropriate CRS port patterns that act as intermediaries to facilitate resource allocation while keeping user equipment implementation straightforward.
4Productivity
If spectrum is dynamically shared between LTE and NR, then spectrum utilization efficiency improves, but control channel resource allocation becomes constrained
Solution Approach 1:
The patent implements dynamic spectrum sharing through dynamic CRS port configuration that adapts to traffic conditions. The system can switch between 2 and 4 CRS port configurations to optimize spectrum utilization for either LTE or NR based on current demands, making the spectrum sharing flexible and efficient.
Solution Approach 2:
The CRS port configuration mechanism serves multiple functions: it controls LTE reference signal transmission, enables NR control channel allocation, and facilitates dynamic spectrum sharing. This multi-functional approach simplifies the overall control channel allocation by using a single configurable parameter to achieve multiple objectives.
Data Source
AI summary
There is provided mechanisms for transmission of NR control information in a LTE downlink subframe. At least two symbols in the subframe are allocatable for LTE control information. A method is performed by a network node. The method comprises obtaining information that the symbol at index 1 in the subframe allocatable for LTE control information is to be allocated to the NR control information. The method comprises, in response thereto, configuring resource elements for LTE transmission and resource elements for NR transmission within the subframe. The resource elements for LTE transmission in the symbol at index 1 in the subframe are to be muted. The NR control information is allocated to resource elements of the symbol at index 1 in the subframe. The method comprises initiating transmission of the subframe.