Semi-Persistent Scheduling Configuration for MTC Devices
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Solution Overview
Problem
Current systems face challenges in efficiently managing resource allocations for energy-deprived Machine Type Communication (MTC) devices, particularly in interacting with Discontinuous Reception (DRX) mechanisms, leading to potential conflicts and delays in data transmission, especially when using semi-persistent scheduling (SPS) in cellular networks.
Innovation Solution
The proposed solution modifies the SPS mechanism to allow multiple uplink SPS allocations during a DRX active period with short time gaps, synchronizes SPS cycles with DRX cycles, and includes options for TTI bundling and explicit interaction with DRX functionality to avoid conflicts and reduce delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If semi-persistent scheduling (SPS) is used to proactively allocate uplink resources, then energy consumption in the UE is reduced, but transmission delays occur when the UE has no data to transmit or when a single SPS resource is insufficient
Solution Approach 1:
The patent introduces dynamic adjustment mechanisms for SPS configuration parameters including repetition interval, active period length, and number of SPS resources. The eNodeB can adaptively modify these parameters based on UE buffer status, channel conditions, and traffic patterns, allowing the system to transition between energy-saving mode and high-transmission mode as needed
Solution Approach 2:
The patent modifies key SPS parameters such as the repetition interval (configurable in ranges like 2-64 subframes), active period duration, and maximum number of SPS resources (configurable up to 8). These parameter changes enable the system to optimize between energy consumption and transmission speed based on current network conditions and UE requirements
2Device complexity
If a single SPS resource allocation is provided, then resource allocation simplicity is maintained, but the UE cannot transmit all queued data during a DRX active period
Solution Approach 1:
The patent segments the SPS resource allocation into multiple discrete resources (SPS0, SPS1, ..., SPS7) that can be independently configured and activated. Each SPS resource can be individually managed with its own timing and resource characteristics, allowing the UE to transmit data in multiple stages during the active period
Solution Approach 2:
The patent adds the dimension of multiple SPS resource instances along the time axis, where resources are distributed across different subframes within the active period. This transforms the single-resource model into a multi-resource timeline structure, enabling parallel and sequential data transmissions
3Speed
If SPS resources are allocated frequently, then data transmission speed is improved, but battery life of energy-deprived MTC devices is reduced
Solution Approach 1:
The patent implements periodic SPS resource allocation where resources are granted at regular intervals defined by the repetition interval parameter. The UE enters sleep mode between active periods, and SPS resources are activated periodically only when needed, creating a rhythm of activity and rest that balances transmission speed with energy conservation
Solution Approach 2:
The patent enables the UE to autonomously monitor its own buffer status and trigger SPS resource activation only when data is available for transmission. The UE can also request additional SPS resources or adjust existing configurations based on its own traffic patterns, eliminating the need for continuous network-side resource allocation
Data Source
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AI summary
A base station (18) generates configuration information for Semi-Persistent Scheduling (SPS) resource allocation to a wireless device (20), such as a User Equipment (UE), for example. The configuration information configures a set of multiple SPS resources to reoccur within a first time interval of the wireless device, but does not configure SPS resources to occur in a second time interval of the wireless device (20). The base station (18) also signals the configuration information to the wireless device (20). Upon receipt, a controller (22) at the wireless device (20) configures the wireless device (20) to receive or transmit data over the set of SPS resources according to the received configuration information.