Half-Duplex FDD Scheduling via Segmented Uplink Downlink Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern cellular communication systems face complexity in supporting half-duplex frequency division duplex (FDD) devices due to scheduling conflicts between data and control traffic, which is not present in full-duplex FDD systems, making concurrent support challenging.
Innovation Solution
Defining and applying a transmit/receive pattern with predefined timing offsets for half-duplex capable devices, allowing specific subframes for uplink and downlink transmissions, and configuring messages to base stations to identify devices capable of half-duplex operation, thereby simplifying scheduling and reducing implementation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If half-duplex FDD operation is implemented to reduce device cost, then device cost is reduced, but scheduling complexity increases due to conflicts between data and control traffic
Solution Approach 1:
The scheduling process is segmented into two independent parts: the downlink scheduler handles downlink data and control traffic without considering uplink state, while the uplink scheduler handles uplink traffic independently. This segmentation eliminates the need for the downlink scheduler to track uplink transmissions and vice versa, reducing scheduling complexity while maintaining half-duplex operation
Solution Approach 2:
The system pre-configures half-duplex capable devices with information about their transmit and receive patterns before communication begins. This preliminary configuration allows the device to autonomously know when to transmit and when to receive, eliminating the need for real-time scheduling coordination and reducing overall scheduling complexity
2Measurement precision
If the downlink scheduler tracks uplink transmissions to avoid conflicts, then scheduling accuracy improves, but scheduler complexity increases
Solution Approach 1:
The scheduling function is divided into separate downlink and uplink schedulers that operate independently. The downlink scheduler focuses solely on downlink resource allocation without needing to track uplink transmissions, while uplink scheduling is handled separately. This segmentation maintains scheduling accuracy for each direction while reducing the complexity of individual schedulers
Solution Approach 2:
A pre-configured transmit/receive pattern acts as an intermediary between the uplink and downlink scheduling functions. This pattern provides the necessary coordination information without requiring direct interaction between the schedulers, allowing them to operate independently while still avoiding conflicts
3Measurement precision
If the uplink scheduler is aware of downlink ACK/NACK transmissions, then scheduling accuracy improves, but scheduler complexity increases
Solution Approach 1:
The scheduling system is segmented into independent uplink and downlink schedulers. The uplink scheduler handles uplink resource allocation without needing to track downlink ACK/NACK transmissions, while downlink scheduling is handled separately. This segmentation maintains scheduling accuracy for each direction while reducing the complexity burden on individual schedulers
Solution Approach 2:
The transmit/receive pattern is pre-configured to include information about both uplink and downlink subframes. This preliminary information provides the uplink scheduler with knowledge of upcoming downlink transmissions without requiring real-time tracking, maintaining scheduling accuracy while reducing complexity
4Adaptability or versatility
If half-duplex and full-duplex devices are supported concurrently in the same system, then system versatility improves, but implementation complexity increases
Solution Approach 1:
The segmented scheduling approach and pre-configured transmit/receive patterns create a universal framework that can accommodate both half-duplex and full-duplex devices. Full-duplex devices simply use all available subframes while half-duplex devices follow their configured patterns, allowing the system to support multiple device types without requiring different scheduling mechanisms
Solution Approach 2:
The system applies different scheduling approaches locally to different device types. Half-duplex devices receive pre-configured transmit/receive patterns that restrict their operation to avoid conflicts, while full-duplex devices operate without such restrictions. This local differentiation maintains system versatility while managing implementation complexity through targeted rather than universal solutions
Data Source
AI summary
Systems and techniques are described for scheduling communication by half-duplex devices. One or more half-duplex devices informs a base station that it is capable only of half-duplex operation. For each such device, the base station configures a transmit/receive pattern comprising sequences of uplink and downlink subframes and applies the pattern to the device. The half-duplex device may receive during a downlink subframe and may transmit during an uplink subframe. Uplink and downlink subframes within a pattern are separated by an offset based at least in part on a number of hybrid automatic repeat request processes.