Multiple HARQ Processes in NB-IoT Radio Devices
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Solution Overview
Problem
Current NB-IoT systems are limited to a single HARQ process in both downlink and uplink, which restricts data throughput and increases latency due to the need for a HARQ process to complete before another can be scheduled, leading to inefficient resource management and higher power consumption.
Innovation Solution
Implementing a method that allows for multiple HARQ processes in both downlink and uplink by using a specific eNB scheduling strategy and UE behavior, enabling the radio device to monitor for resource grants of subsequent HARQ processes while the previous ones are still active, thereby supporting simultaneous operation of two HARQ processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single HARQ process is used in NB-IoT, then device complexity and power consumption are reduced, but data throughput is limited and latency increases
Solution Approach 1:
The patent segments the HARQ operation into multiple independent processes (first HARQ process and second HARQ process), allowing parallel data transmission. The UE is configured to monitor multiple Downlink Control Information (DCI) formats, each associated with a different HARQ process, enabling simultaneous handling of multiple data streams without increasing individual process complexity
Solution Approach 2:
The patent introduces a new dimension to HARQ operation by implementing both uplink and downlink HARQ processes simultaneously. The UE monitors for uplink DCI formats for uplink HARQ processes and downlink DCI formats for downlink HARQ processes, effectively adding a spatial dimension to the previously sequential single-process operation
2Loss of time
If a single HARQ process is used in NB-IoT, then device complexity is reduced, but latency increases due to sequential processing
Solution Approach 1:
The patent divides the HARQ operation into multiple parallel segments (first and second HARQ processes), each capable of independent data transmission and acknowledgment. This segmentation eliminates the sequential waiting time where the UE had to complete one HARQ process before starting another, thereby reducing overall latency
Solution Approach 2:
The patent enables continuous useful action by allowing the UE to simultaneously monitor and process multiple HARQ processes. While one HARQ process is waiting for acknowledgment, another process can be actively transmitting or receiving data, ensuring that the UE is continuously engaged in productive communication activities rather than idle waiting
3Use of energy by moving object
If the UE stops monitoring NPDCCH after receiving a downlink assignment, then power consumption is reduced, but multiple HARQ processes cannot be supported
Solution Approach 1:
The patent introduces dynamic monitoring behavior where the UE adapts its NPDCCH monitoring based on the type of DCI received. The UE dynamically switches between monitoring modes: monitoring both uplink and downlink DCI formats when uplink HARQ processes are active, and monitoring only downlink DCI formats when downlink HARQ processes are active. This dynamic approach maintains power efficiency while enabling multiple HARQ processes
Solution Approach 2:
The patent implements periodic monitoring patterns where the UE monitors NPDCCH at specific intervals based on configured monitoring occasions. Rather than continuously monitoring, the UE checks for DCI formats at predetermined periods, reducing power consumption while still detecting scheduling assignments for multiple HARQ processes in a timely manner
Data Source
AI summary
A radio device (110) and/or network node (105) support multiple HARQ processes. In particular, responsive to the radio device (110) receiving a resource grant for a first HARQ process, the radio device (110) starts or restarts a timer that configures the radio device (110) to monitor for a resource grant of a second HARQ process. Additionally or alternatively, the network node (105) transmits a resource grant for a first HARQ process and a resource grant for a second HARQ process to the same radio device (110).