CPRI Microwave Transmission Adaptation for Distance
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Solution Overview
Problem
In CPRI frame transmission over microwave channels, poor channel quality prevents the transmission of antenna-carrier I/Q data using higher order modulation formats, leading to a limited transmission distance due to the need for a high signal-to-noise ratio and large fade margin.
Innovation Solution
A method and device that separately process the control word and antenna-carrier I/Q data in the CPRI frame, adjusting modulation formats based on channel quality, generating a microwave air interface frame using modulated data only when channel quality is insufficient, thereby reducing the need for a large fade margin and extending transmission distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large fade margin is reserved for poor channel quality, then transmission reliability is improved, but transmission distance is limited due to high signal-to-noise ratio requirements
Solution Approach 1:
The patent segments the antenna-carrier I/Q data into multiple groups and applies different modulation formats to each group based on channel quality. This allows the system to transmit some data at higher rates with lower fade margins while maintaining overall reliability, thus extending transmission distance without sacrificing reliability.
Solution Approach 2:
Different portions of the data stream are assigned different modulation qualities - some groups use higher order modulation (requiring larger fade margin) while others use lower order modulation (tolerating smaller fade margin). This local differentiation allows the system to achieve acceptable overall reliability with a reduced total fade margin, enabling longer transmission distances.
2Productivity
If higher order modulation format is used in CPRI frame, then spectrum utilization is improved, but transmission fails when channel quality becomes poor
Solution Approach 1:
The system dynamically adjusts the modulation format for different data groups based on current channel conditions. When channel quality is good, higher order modulation is applied to maximize spectrum utilization. When channel quality deteriorates, the system switches to more robust lower order modulation for affected groups, ensuring transmission success while maintaining overall productivity.
Solution Approach 2:
The patent changes the modulation format parameter for different groups of antenna-carrier I/Q data according to channel quality measurements. This parameter adaptation allows the system to optimize between spectrum utilization and transmission reliability - using higher order modulation (better spectrum utilization) when possible, and lower order modulation (better reliability) when necessary.
Data Source
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AI summary
Embodiments of the present invention relate to the communications field, and provide a data sending method, a data receiving method, a device, and a system. The data sending method includes: receiving a common public radio interface CPRI frame, and obtaining a control word CW and antenna-carrier I/Q data from the CPRI frame, where the antenna-carrier I/Q data includes first I/Q data; modulating the CW to obtain a modulated CW; copying the first I/Q data to obtain two pieces of first I/Q data, and modulating a first piece of first I/Q data to obtain modulated first I/Q data; determining whether channel quality of a microwave channel meets a requirement; and if the channel quality of the microwave channel does not meet the requirement, generating a first microwave air interface frame based on the modulated first I/Q data and the modulated CW, and sending the first microwave air interface frame by using the microwave channel. According to the embodiments of the present invention, a transmission distance requirement for a microwave system can be met, and spectrum utilization is high.