Uplink Scheduling via Time Offset Buffer Prediction
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Solution Overview
Problem
In LTE wireless communication systems, the current uplink scheduling mechanism is inefficient due to the lack of accurate data generation time information, leading to increased delays and battery consumption in user equipment, especially for delay-sensitive services like VoIP, as the eNodeB schedules transmissions blindly without knowing the buffer state, resulting in suboptimal resource allocation and increased signaling requirements.
Innovation Solution
The method involves the user equipment computing and transmitting a time offset value to the base station, indicating the difference between data generation and scheduling request times, allowing the base station to predict the buffer state and schedule resources more accurately, thereby reducing delays and signaling needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the eNodeB schedules uplink transmissions blindly without knowing the buffer state, then the scheduling mechanism can operate without complex feedback mechanisms, but the scheduling efficiency deteriorates and delays increase
Solution Approach 1:
The patent introduces an intermediary mechanism where the UE sends scheduling requests and buffer status reports through predefined uplink resources (PUCCH for SR, PUSCH for BSR). This intermediary feedback channel allows the eNodeB to obtain buffer state information without requiring complex continuous negotiation, thus improving scheduling efficiency while maintaining manageable system complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the UE periodically reports buffer status to the eNodeB using BSR messages transmitted on PUSCH, and sends scheduling requests on PUCCH when data arrives. This feedback loop enables the eNodeB to make informed scheduling decisions, directly improving scheduling efficiency and reducing delays for delay-sensitive services.
2Device complexity
If the D-SR interval is used for scheduling requests, then the PUCCH resource usage is simplified and standardized, but the delay between data generation and scheduling request transmission increases
Solution Approach 1:
The patent makes the SR transmission dynamic by allowing the UE to send scheduling requests at predefined PUCCH resources when data arrives, rather than waiting for fixed periodic opportunities. The UE can transmit SR immediately when buffer data exceeds a threshold, adapting to varying traffic conditions while using standardized PUCCH resources, thus reducing delay without increasing complexity.
Solution Approach 2:
The patent establishes predefined PUCCH resources and SR transmission rules in advance through RRC configuration. This preliminary setup allows the UE to immediately transmit scheduling requests when data arrives without needing to negotiate resources dynamically, reducing transmission delay while maintaining standardized resource usage.
3Productivity
If Buffer Status Reports are transmitted on PUSCH together with user data, then the uplink resource utilization is improved, but the signaling overhead increases and delays data arrival at the eNodeB
Solution Approach 1:
The patent combines BSR transmission with user data transmission on the PUSCH when data is already scheduled for uplink transmission. This merging approach improves uplink resource utilization by using existing data transmissions to carry buffer status information, avoiding separate dedicated BSR transmission resources while maintaining efficient resource usage.
Solution Approach 2:
The patent implements truncated BSR mechanisms that send only the most critical buffer status information when resources are limited or time is critical. This allows the essential buffer status to be transmitted quickly alongside user data without waiting for complete buffer status compilation, reducing information availability delay while maintaining efficient uplink utilization.
4Device complexity
If the terminal sends scheduling requests only at predefined D-SR intervals, then the PUCCH resource allocation is simplified, but the battery consumption increases due to longer active monitoring periods
Solution Approach 1:
The patent implements periodic DRX cycles where the UE can enter sleep mode and wake up at predefined intervals to check for scheduling opportunities. Combined with SR transmission at predefined PUCCH resources, this periodic action allows the UE to maintain simple resource allocation while reducing active monitoring time, thereby lowering battery consumption without complicating resource management.
Data Source
AI summary
Methods and arrangements in a base station are provided for scheduling radio resources to a user equipment. A time offset value is received that is associated with the moment of time when a frame of data was generated in the user equipment buffer. The moment of time when the frame of data was generated in the user equipment buffer is determined, based on the received time offset value. Thus, the buffer state of the user equipment buffer is predicted by using the determined moment of time when the frame of data was generated in the user equipment buffer. Radio resources are granted to the user equipment, based on the predicted buffer state of the user equipment buffer. Methods and arrangements in a user equipment for assisting the base station in scheduling radio resources are also provided herein.