Cross-Subframe Scheduling for MTC Broadcast Reliability
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Solution Overview
Problem
Current 3GPP standards lack flexible cross-subframe scheduling for broadcast transmissions, particularly for machine-type communication (MTC) devices, which have limited bandwidth and complexity, making it difficult for them to receive and monitor control data and messages across multiple subframes and resource blocks.
Innovation Solution
Implementing cross-subframe scheduling for broadcast transmissions, such as random access and paging messages, by using the evolved physical downlink control channel (EPDCCH) with dynamic scheduling and retuning times, allowing MTC devices to receive messages in subsequent subframes and resource blocks, and using a new RA-RNTI derived from the PRACH sequence index to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MTC devices monitor control channels and broadcast transmissions across multiple subframes and resource blocks, then the reliability of message reception is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent segments the monitoring process by dividing resource blocks into multiple groups and assigning different monitoring patterns to different subframes. MTC devices monitor only specific resource block groups in specific subframes according to their device type, rather than monitoring all resource blocks continuously. This segmentation reduces the monitoring complexity and power consumption while maintaining reliable message reception through distributed monitoring across multiple subframes.
2Reliability
If MTC devices monitor control channels and broadcast transmissions across multiple subframes and resource blocks, then the reliability of message reception is improved, but the power consumption increases
Solution Approach 1:
The patent implements periodic monitoring patterns where MTC devices monitor control channels and broadcast transmissions in specific subframes according to a periodic schedule. Different device types (e.g., coverage-enhanced MTC devices versus non-coverage-enhanced MTC devices) have different periodic monitoring patterns. This periodic action allows devices to enter low-power states between monitoring instances while ensuring reliable message reception at scheduled intervals.
3Adaptability or versatility
If cross-subframe scheduling is implemented for broadcast transmissions, then the flexibility of resource allocation is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by implementing different monitoring configurations for different resource block groups and different subframes. Specifically, control resource blocks are divided into multiple groups, and each group is monitored in specific subframes according to device type. This localized differentiation provides scheduling flexibility for the network while keeping the monitoring rules simple and device-type-specific, thereby limiting the complexity increase at the device side.
Data Source
AI summary
A communication system is disclosed in which communication devices communicate with a base station using radio frames made up of a sequence of subframes and a frequency band made up of frequency subbands. The base station identifies a subframe in which a broadcast message, carrying information for at least one communication device, is to be broadcast; transmits, in a control channel, in a frequency subband in a current subframe that precedes the identified subframe, control information to identify said subframe in which said broadcast message is to be broadcast; and transmits the broadcast message in the identified subframe.