Enhanced PBCH Transmission for MTC Coverage
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Solution Overview
Problem
Current LTE systems face challenges in providing enhanced coverage for Machine Type Communication (MTC) devices, particularly in scenarios where signal attenuation is significant, such as underground or within buildings, leading to communication failures and increased network deployment costs.
Innovation Solution
The method involves determining and mapping resources in radio frames for enhanced Physical Broadcast Channel (PBCH) transmission, specifically using Resource Elements (REs) not occupied by legacy PBCH, SSSs, PDCCHs, and CRS ports, to improve coverage by retransmitting or rate-matching channels, thereby increasing coverage by 15 dB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the existing LTE coverage is used, then the network deployment cost is low, but the coverage is insufficient for MTC devices in shielded scenarios
Solution Approach 1:
The PBCH transmission is segmented into multiple repetitions across different subframes (up to 100 times or more), allowing the broadcast information to be transmitted incrementally. This segmentation enables the system to achieve enhanced coverage by accumulating signal energy over time without requiring a complete network redesign, thus resolving the contradiction between coverage area and communication reliability.
Solution Approach 2:
The patent implements periodic retransmission of the PBCH at regular intervals, with the PBCH repeated periodically across multiple radio frames. This periodic action allows MTC devices to accumulate signal energy over multiple periods, achieving 15 dB coverage enhancement while maintaining network deployment costs at acceptable levels.
2Area of stationary object
If the PBCH is retransmitted nearly 100 times to enhance coverage by 15 dB, then the coverage is enhanced, but the transmission time and system complexity increase
Solution Approach 1:
The system performs preliminary rate-matching and coding of the PBCH information before transmission, optimizing the data structure for repeated transmissions. This preliminary action reduces the processing burden during each retransmission cycle and enables more efficient use of transmission time, allowing 100+ repetitions to be performed without linearly increasing system complexity.
Solution Approach 2:
The patent uses identical copies of the PBCH information across multiple transmissions rather than varying the content. This copying approach simplifies the transmission process significantly, as the same encoded and rate-matched data can be repeatedly transmitted without requiring complex processing for each repetition, thus reducing transmission time overhead.
3Area of stationary object
If the PBCH is retransmitted nearly 100 times to enhance coverage by 15 dB, then the coverage is enhanced, but the device complexity increases
Solution Approach 1:
The patent designs the PBCH repetition mechanism to serve multiple functions simultaneously: it provides coverage enhancement, enables signal accumulation, maintains backward compatibility with legacy devices, and supports MTC-specific requirements. This multi-functionality reduces the need for separate specialized mechanisms, thereby limiting the increase in device complexity while achieving 15 dB coverage enhancement.
Solution Approach 2:
The system changes key transmission parameters including the number of repetitions (up to 100), the coding rate, and the resource allocation pattern to optimize for MTC coverage enhancement. These parameter changes are configured at the network side and communicated to devices, allowing the system to achieve enhanced coverage without requiring complex adaptive processing at the device level.
Data Source
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AI summary
The present application relates to the technical field of wireless communications, and in particular, to a PBCH transmission method, system, and device, which are used to transmit an enhanced PBCH. The method of the present application comprises: a network side device determining a resource of a coverage-enhanced PBCH mapped in at least one radio frame; and the network side device transmitting the coverage-enhanced PBCH on the determined resource. In the present application, a network side device determines a resource of a coverage-enhanced PBCH mapped in at least one radio frame, and transmits the coverage-enhanced PBCH on the determined resource. Because a resource that bears a coverage-enhanced PBCH can be determined, thereby implementing transmission of the coverage-enhanced PBCH and improving system performance.