Wireless Network Scheduling Using Preliminary Action
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Solution Overview
Problem
In wireless communication systems, the rapidly fluctuating interference environment makes it difficult for base stations to determine appropriate modulation and coding selection during link adaptation, leading to lower data rates and reduced system capacity due to the need for significant fade margins.
Innovation Solution
The implementation of synchronously fixed scheduling (SFS) and frequency selective scheduling (FSS) methods, where user devices are scheduled in coordinated time intervals to exploit signal up-fades and maintain consistent interference and multipath environments, allowing for more accurate modulation and coding selection based on past measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If base station selects user device independently with fast changing interference environment, then scheduling flexibility is improved, but modulation and coding selection accuracy deteriorates
Solution Approach 1:
The system performs preliminary actions by scheduling user devices in advance for multiple future slots and pre-notifying them of resource allocations. This allows the base station to lock in interference measurements taken at scheduling decision time, rather than at transmission time, thereby decoupling the scheduling flexibility from interference variability and maintaining accurate modulation and coding selection.
Solution Approach 2:
The patent introduces an intermediary mechanism where the base station sends advance notifications to user devices about their scheduled resource allocations before actual transmission occurs. This intermediary step allows the system to separate the scheduling decision (made when interference is measured) from the actual transmission (occurring when interference may have changed), resolving the contradiction between scheduling flexibility and measurement accuracy.
2Reliability
If base station uses considerable fade margin to minimize transmission errors, then transmission reliability is improved, but data rate and system capacity deteriorate
Solution Approach 1:
By making scheduling decisions in advance and locking in interference measurements at the time of scheduling rather than at transmission time, the system can determine accurate channel conditions beforehand. This preliminary action eliminates the need for excessive fade margins, as the modulation and coding selection is based on actual measured interference rather than worst-case assumptions, thereby improving data rates while maintaining reliability.
3Measurement precision
If base station determines interference dynamically for each transmission, then interference measurement accuracy is improved, but system complexity and processing overhead increase
Solution Approach 1:
The system performs interference measurements and determines modulation and coding selections in advance during the scheduling phase, rather than dynamically at each transmission instance. This preliminary determination of interference characteristics allows the base station to maintain accurate measurements without the complexity of real-time dynamic adjustment, as the scheduling decision itself becomes the reference point for interference assessment.
Data Source
AI summary
In accordance with an embodiment, a method of operating a base station configured to operate with user devices includes scheduling a first user device in a first slot, scheduling the first user device for at least one further slot, and transmitting an assignment for the at least one further slot to the first user device. The first slot has a first resource block (RB) and a first transmission time interval (TTI) and the at least one further slot has the first RB and a second TTI.