MIMO Layer Determination for LTE User Equipment
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Solution Overview
Problem
In LTE communication systems, the limited soft buffer size in user equipment leads to reduced effectiveness of soft combining gains during incremental redundancy retransmissions, especially in dual-codeword MIMO operations, and there is a need for efficient communication between LTE release 10 user equipment and legacy networks with varying MIMO layer support.
Innovation Solution
The base station and user equipment communicate based on selectable user equipment categories, determining the maximum supported transmission layers to ensure synchronized understanding and operation within the capabilities of both devices, preventing scheduling errors and corrupted signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE release 10 user equipment with higher MIMO layer capabilities operates in legacy networks, then communication capacity and data rate are improved, but scheduling errors and corrupted signaling occur due to mismatched MIMO layer understanding
Solution Approach 1:
The patent implements dynamic adaptation of MIMO layer configuration based on network type detection. The user equipment dynamically switches between release 10 behavior (higher MIMO layers) for LTE-A networks and release 8 behavior (lower MIMO layers) for legacy networks, resolving the contradiction between capacity and reliability
Solution Approach 2:
The patent changes the operational parameters (MIMO layer count, soft buffer allocation) based on the detected network release type. By detecting whether the base station is LTE-A or legacy, the UE adjusts its parameters to match network capabilities, preventing scheduling errors while maintaining optimal performance
2Reliability
If user equipment increases soft buffer size to store complete codewords for incremental redundancy, then error recovery capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies partial action by allocating soft buffer resources proportionally to the actual number of MIMO layers being used. Instead of always provisioning for maximum layers, the buffer size adapts to current operational needs, reducing memory requirements while maintaining sufficient error recovery capability
Solution Approach 2:
The soft buffer allocation is made dynamic, changing based on the number of active MIMO layers. The buffer size expands when more layers are active and contracts when fewer layers are used, optimizing the balance between error recovery capability and device complexity
3Adaptability or versatility
If user equipment supports multiple UE categories with different MIMO capabilities, then adaptability to different networks is improved, but device complexity and configuration management increase
Solution Approach 1:
Instead of having the user equipment proactively report its capabilities to the base station (which would require complex capability reporting mechanisms), the patent inverts the approach: the base station indicates its type through system information, and the UE passively adapts its behavior accordingly, simplifying configuration management
Solution Approach 2:
The patent implements a universal detection mechanism that works across different network types and releases. The UE uses a single detection procedure to identify LTE-A versus legacy networks, and a single adaptation logic to adjust MIMO parameters, providing multi-functionality without increasing complexity
Data Source
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AI summary
The embodiments herein relate to a method in a base station (603) for communicating with a user equipment (605) in the communication network (600). The base station (603) is configured to communicate with the user equipment (605) according to a selectable of at least two user equipment categories. Based on information about a selected user equipment category, the base station (603) determines a first number of maximum transmission layers supported by the base station (603). The base station (603) communicates with the user equipment (605) according to up to the determined first number of maximum transmission layers and according to the selected user equipment category.