EPDCCH Resource Allocation for MTC Frequency Switching
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Solution Overview
Problem
Low-cost Machine Type Communication (MTC) devices face challenges in efficient data transmission due to limited RF bandwidth and frequency switching requirements, particularly in coexisting with legacy UE systems, where EPDCCH resource consumption is significant and frequency multiplexing is necessary to support 1.4 MHz bandwidth.
Innovation Solution
The method involves using EPDCCH to indicate resource blocks for transmitting cell common messages and downlink data, with frequency-division and time-division multiplexing to efficiently allocate resources, allowing MTC UE to switch between subbands and optimize resource utilization across the entire system bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If EPDCCH is introduced to carry common control channels for LC-MTC UE, then the ability to support frequency multiplexing and coexistence with legacy UE is improved, but the resource consumption increases significantly as EPDCCH occupies up to 8 PRBs
Solution Approach 1:
The patent segments the control channel resources by introducing separate EPDCCH resources specifically for LC-MTC UE, distinct from legacy PDCCH resources. This segmentation allows frequency multiplexing of different UE types while dedicating only necessary resources (1-2 PRBs) to LC-MTC control channels, resolving the contradiction between adaptability and resource consumption.
Solution Approach 2:
The patent introduces a new dimension in resource allocation by using frequency-division multiplexing to separate LC-MTC EPDCCH from legacy PDCCH in the frequency domain. This dimensional separation enables coexistence while optimizing resource usage, as LC-MTC UE can be configured to monitor specific frequency locations rather than spanning the entire bandwidth.
2Device complexity
If LC-MTC UE is constrained to 1.4 MHz bandwidth to reduce device cost, then device complexity and cost are reduced, but the ability to utilize the entire system bandwidth for data transmission is limited
Solution Approach 1:
The patent segments the system bandwidth into multiple 1.4 MHz subbands, allowing LC-MTC UE to operate within a single subband for cost reduction while the network can allocate different subbands to different LC-MTC UEs. This segmentation enables frequency multiplexing of multiple LC-MTC UEs across the entire system bandwidth, maintaining productivity while preserving device simplicity.
Solution Approach 2:
The patent creates a universal frequency multiplexing mechanism that allows the same 1.4 MHz bandwidth constraint to serve multiple LC-MTC UEs simultaneously across different frequency locations. The EPDCCH configuration enables flexible allocation of time-frequency resources, making the limited bandwidth capability universal across multiple devices and improving overall system productivity.
3Quantity of substance
If EPDCCH occupies only 1 PRB to minimize resource consumption, then resource efficiency is improved, but only 16% of total resource is available for EPDCCH leaving 84% for data and other control messages
Solution Approach 1:
The patent employs periodic repetition of EPDCCH transmissions across multiple subframes to enhance control channel coverage. By repeating the control information in different time instances, the system ensures reliable reception even with minimal frequency resources (1 PRB), as the temporal diversity provides redundancy for robust decoding, resolving the contradiction between resource consumption and reliability.
Data Source
AI summary
The present invention provides a method for data transmission in a machine type communication device terminal, comprising: performing the following when the terminal receives cell common message: A. receiving first indication information from an EPDCCH on a first resource block, the first indication information indicating a second resource block for transmitting the cell common message; B. receiving the cell common message from a PDSCH on the second resource block; performing the following when the terminal receives downlink data: I. receiving second indication information from EPDCCH on a third resource block; II. detecting whether DCI information transmitted to the terminal exists in the second indication information, and if the DCI information transmitted to the terminal exists, II-1. decoding information of a fourth resource block in the DCI information; II-2. receiving the downlink data transmitted from the base station to the terminal from the PDSCH on the fourth resource block.