Cross-Subframe Scheduling for MTC Buffer Reduction
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Solution Overview
Problem
Existing mobile broadband networks are not optimized for Machine-Type Communication (MTC) requirements, leading to high costs and power consumption in MTC devices, particularly due to their limited bandwidth of 1.4 MHz for both control and data channels, which affects the efficiency of physical downlink control channel scheduling.
Innovation Solution
The implementation of cross-subframe scheduling for enhanced physical downlink control channel (EPDCCH) transmissions, allowing PDSCH data to be scheduled in a different subframe from the EPDCCH, reducing buffer size and enabling improved Hybrid Automatic Repeat Request (HARQ) operations for MTC devices with reduced bandwidth support, including those operating in half-duplex frequency division duplex (HD-FDD) mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If MTC devices use limited bandwidth of 1.4 MHz for both control and data channels, then device cost and power consumption are reduced, but scheduling efficiency and resource allocation flexibility deteriorate
Solution Approach 1:
The patent introduces cross-subframe scheduling that separates control channel timing from data channel timing across different subframes. This temporal dimension separation allows MTC devices to operate efficiently in 1.4 MHz bandwidth while maintaining scheduling flexibility, as control and data transmissions are no longer constrained to the same subframe boundary.
Solution Approach 2:
The patent enables dynamic HARQ timing adjustment by allowing PDSCH transmissions in subframes different from the EPDCCH subframe. This dynamic timing flexibility optimizes resource utilization for MTC devices with limited bandwidth, improving scheduling efficiency without requiring increased device complexity or power consumption.
2Loss of time
If EPDCCH schedules PDSCH in the same subframe, then processing time is reduced, but resource collision and scheduling flexibility increase
Solution Approach 1:
The patent segments the scheduling process into distinct control subframes and data subframes. EPDCCH in one subframe can schedule PDSCH in a different subframe, allowing independent optimization of control and data resource allocation. This segmentation resolves the conflict between fast processing and flexible scheduling by decoupling the timing constraints.
Solution Approach 2:
The patent introduces cross-subframe scheduling as an intermediary mechanism that mediates between control channel timing and data channel timing. This allows the system to maintain short processing times while achieving scheduling flexibility through the temporal separation of control and data transmissions.
3Quantity of substance
If multiple MTC regions with 1.4 MHz bandwidth are allocated, then more MTC devices can be supported, but device complexity and cost increase
Solution Approach 1:
The patent creates a universal scheduling framework that works across multiple 1.4 MHz MTC regions using the same cross-subframe scheduling mechanism. This multi-functional approach allows a single device design to operate efficiently in any MTC region without increasing complexity, as the scheduling principles remain consistent across different frequency allocations.
Data Source
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AI summary
The present disclosure describes embodiments of apparatuses, systems, and methods for cross sub-frame by enhanced physical downlink control channel (EPDCCH) transmissions for scheduling of physical downlink share channel (PDSCH) transmissions one or more subframes after the EPDCCH transmission. Cross subframe scheduling may be useful for machine type communication (MTC) user equipment (UE) with reduced bandwidth support including half duplex type MTC UE operating at 1.4 MHz bandwidth.