Parallel PDSCH Scheduling for Random Access Response Position Indication
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Solution Overview
Problem
In Machine Type Communication (MTC) devices, the high repetition of physical channels for coverage enhancement reduces spectral efficiency, and existing methods for reducing complexity and cost in Low Complexity MTC (LC-MTC) UEs do not effectively address power consumption and resource allocation during random access response windows.
Innovation Solution
A base station with a processing circuit and transceiver schedules parallel physical downlink shared channel transmissions and assigns wireless resources based on preambles received from user equipment, allowing for simultaneous transmission of random access responses and control channels during a random access response window, reducing the need for repetitive decoding by user equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical channels are repeated multiple times for coverage enhancement, then coverage is improved, but spectral efficiency deteriorates
Solution Approach 1:
The random access response window is segmented into multiple slots, with each slot containing a parallel PDSCH transmission. This segmentation allows the system to divide the coverage enhancement task across multiple time slots rather than repeating the entire channel sequence, thereby improving spectral efficiency while maintaining coverage.
Solution Approach 2:
The base station transmits downlink control information (DCI) in advance within the random access response window to indicate the slot position of the PDSCH transmission. This preliminary action enables user equipment to directly locate and decode the random access response without performing multiple blind decodings, reducing power consumption and improving efficiency.
2Reliability
If user equipment performs blind decoding of multiple physical downlink control channel repetitions, then coverage is improved, but power consumption increases
Solution Approach 1:
The base station provides downlink control information in advance that explicitly indicates the slot position where the PDSCH transmission will occur. This preliminary indication allows user equipment to skip blind decoding of intermediate control channel repetitions and directly decode the random access response at the indicated position, significantly reducing power consumption.
Solution Approach 2:
The downlink control information acts as an intermediary that carries position indication information. This intermediary enables user equipment to efficiently locate the random access response without exhaustive blind decoding, resolving the contradiction between coverage reliability and power consumption.
3Device complexity
If random access responses are transmitted sequentially, then resource allocation is simplified, but transmission efficiency deteriorates
Solution Approach 1:
The random access response transmissions are segmented into parallel PDSCH transmissions across multiple slots within the random access response window. Each slot contains a complete random access response, allowing simultaneous transmission to different user equipment and improving overall transmission efficiency.
Solution Approach 2:
The base station performs preliminary scheduling and assigns specific slot positions for each PDSCH transmission before the random access response window begins. This preliminary resource allocation enables efficient parallel transmissions while maintaining manageable complexity through pre-planned resource distribution.
Data Source
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AI summary
A base station (105) includes a processing circuit (210) and a transceiver (220). The processing circuit includes a scheduler (215) configured to: schedule a plurality of physical downlink shared channel transmissions in parallel, a first physical downlink shared channel transmission, among the plurality of physical downlink shared channel transmissions, including a random access response for a first user equipment (110), and the plurality of physical downlink shared channel transmissions being scheduled for transmission to a plurality of user equipments (110) during a random access response window. The transceiver circuit is configured to transmit the plurality of physical downlink shared channel transmissions to the plurality of user equipments during the random access response window.