Multi-stage PDCCH Scheduling for HARQ Process Allocation
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Solution Overview
Problem
HARQ process starvation occurs due to insufficient HARQ processes compared to the HARQ-ACK timeline, especially with larger round trip delays, which can lead to inefficiencies in data transfer and increased processing delays.
Innovation Solution
The proposed solution involves using a physical downlink control channel (PDCCH) to transmit first and second scheduling information, where the first scheduling information points to the second scheduling information, which is related to one or more HARQ processes. This allows for the allocation of early and later HARQ processes, enabling efficient data transfer even with larger round trip delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple parallel HARQ processes are used to reduce round trip delay, then data transfer efficiency is improved, but the number of required HARQ processes increases beyond available resources
Solution Approach 1:
The scheduling information is segmented into two parts: first scheduling information transmitted in a first slot, and second scheduling information transmitted in a second slot. This segmentation allows the system to distribute HARQ process allocation across multiple time slots, effectively increasing the number of available HARQ processes without requiring additional parallel processes beyond system resources.
Solution Approach 2:
The first scheduling information is transmitted in advance in the first slot before the actual data transmission. This preliminary action allows the system to prepare and allocate HARQ processes ahead of time, reducing the round trip delay while managing the limited number of available HARQ processes efficiently.
2Reliability
If the number of HARQ processes is increased to handle larger round trip delays, then processing capacity is improved, but system complexity and resource requirements increase
Solution Approach 1:
The system transitions from a single-time-slot scheduling approach to a multi-time-slot approach by introducing a second slot for additional scheduling information. This dimensional change in time allows the system to handle larger round trip delays and increase processing capacity without proportionally increasing system complexity, as the additional scheduling information is distributed across time rather than requiring simultaneous complex processing.
3Reliability
If scheduling information is transmitted more frequently to allocate HARQ processes, then HARQ process starvation is prevented, but control channel overhead increases
Solution Approach 1:
Scheduling information is segmented across two time slots, with first scheduling information in the first slot and second scheduling information in the second slot. This segmentation prevents HARQ process starvation by ensuring scheduling information is transmitted frequently enough, while distributing the control channel overhead across multiple slots rather than concentrating it in a single slot.
Data Source
AI summary
An apparatus comprising means for: receiving, in a physical downlink control channel (PDCCH) in a first slot, first scheduling information for a data channel, wherein the first slot is separated by at least one first period of multiple slots from next first scheduling information; and receiving, in the PDCCH in at least one second slot, second scheduling information for the data channel, wherein the at least one second slot is delayed with respect to the first slot by one or more slots and is received within the first period of multiple slots after the first slot, wherein the first scheduling information in the first slot points to at least the second scheduling information; and wherein the second scheduling information is related to at least one hybrid automatic request (HARQ) process for the data channel.