Cross-Subframe Scheduling for LTE TDD Carrier Aggregation
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Solution Overview
Problem
Carrier aggregation in mobile networks, particularly in LTE TDD systems, faces complexity due to differing TDD configurations among component carriers, leading to challenges in cross-subframe scheduling, especially when a primary carrier has fewer downlink subframes than secondary carriers.
Innovation Solution
The introduction of cross-subframe scheduling methods, including the use of indices and carrier indicator fields, allows for efficient scheduling by treating scheduling information from a primary carrier as if received in a different subframe, enabling proper downlink assignment on secondary carriers with varying configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cross-subframe scheduling is implemented to handle different TDD configurations among component carriers, then scheduling flexibility and network performance are improved, but system complexity increases due to the need for indices and carrier indicator fields
Solution Approach 1:
The patent segments the scheduling process by introducing carrier indicator fields that identify specific component carriers, allowing independent scheduling of each carrier with different TDD configurations. This enables the system to handle multiple configurations simultaneously without requiring a complete redesign of the scheduling mechanism.
Solution Approach 2:
The patent adds a temporal dimension to cross-subframe scheduling by introducing indices that map scheduling decisions across different subframes. This allows scheduling information to be transmitted in one subframe while applying to resource allocation in another subframe, effectively adding a time-based dimension to resolve configuration mismatches.
2Ease of operation
If a primary carrier schedules fewer downlink subframes than secondary carriers require, then resource allocation on the primary carrier is simplified, but scheduling coverage on secondary carriers becomes insufficient
Solution Approach 1:
The patent implements preliminary action by transmitting scheduling decisions in advance through cross-subframe scheduling. The primary carrier can allocate resources for secondary carriers in earlier subframes, allowing the system to prepare scheduling decisions before the actual data transmission occurs. This ensures that even if the primary carrier has fewer downlink subframes, the scheduling information is available beforehand to cover all required secondary carrier subframes.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of cross-subframe scheduling indices that bridge the gap between the primary carrier's scheduling capacity and the secondary carriers' scheduling requirements. This intermediary allows the system to decouple the scheduling decision timing from the actual resource allocation timing, enabling the primary carrier to efficiently schedule multiple secondary carriers despite having fewer downlink subframes.
Data Source
AI summary
A method and user equipment for cross-subframe scheduling at a user equipment, the method receiving an indication for scheduling a subframe; mapping the indication to the subframe; and detecting the subframe on a frequency at a time associated with the subframe. Further, a method and apparatus of cross-carrier scheduling, the method obtaining an indication that at least one downlink subframe on at least one secondary carrier is not scheduled by a primary carrier; and scanning the at least one secondary carrier for scheduling information for the at least one downlink subframe.