Guard Sub-Carrier Data Transmission in OFDM Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving high peak transmission rates due to limited transmission spectrum efficiency, requiring wider radio bandwidths to support next-generation systems like 4G mobile communications, and existing OFDM systems waste bandwidth by reserving guard sub-carriers, which could be utilized for data transmission.
Innovation Solution
The method involves aligning and identifying guard sub-carriers between adjacent frequency channels for data transmission in multi-carrier OFDM systems, using a reference signal to indicate allocation and defining a Subsidiary Carrier for aggregated guard sub-carriers, while implementing a flexible multi-carrier transceiver architecture to support various data transmission schemes, including MIMO and SISO, and enabling data transmission over guard sub-carriers to increase system throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guard sub-carriers are reserved to prevent signal interference between adjacent frequency channels, then signal reliability is improved, but bandwidth utilization deteriorates
Solution Approach 1:
The patent converts the traditionally wasted guard sub-carriers (harmful resource) into useful data transmission resources (benefit). By aligning sub-carrier grids between adjacent frequency channels and identifying non-overlapping guard sub-carriers, the system transforms what was previously considered spectrum waste into productive bandwidth for data transmission, thereby improving bandwidth utilization while maintaining signal reliability through careful resource allocation and NULL sub-carrier reservation where needed.
2Speed
If wider radio bandwidths are used to achieve higher peak transmission rates, then transmission rate is improved, but system complexity deteriorates
Solution Approach 1:
The patent segments the wideband spectrum into multiple frequency channels (e.g., four 10MHz channels in a 40MHz system) with aligned sub-carrier grids. This segmentation approach allows the system to achieve high peak transmission rates over wide bandwidths while managing complexity through structured resource organization. The alignment of sub-carrier grids across channels enables efficient resource management and reduces the complexity of handling wideband signals compared to treating the entire bandwidth as a single channel.
3Productivity
If guard sub-carriers are utilized for data transmission, then system throughput is improved, but signal interference risk deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the treatment of sub-carriers based on their specific locations and overlap characteristics. Instead of uniformly using all guard sub-carriers for data transmission, the system identifies and reserves specific NULL sub-carriers at critical locations where interference could occur, while allowing data transmission on other guard sub-carriers. This localized approach to resource allocation maximizes throughput by utilizing available guard sub-carriers while maintaining signal reliability by protecting vulnerable positions.
Data Source
AI summary
A method of data transmi ssion over guard sub-carrier s is provided in a multi-carrier OFDM system. Adjacent radio fr equency (RF) carriers are used to carry radio signals transmitted through adjacent frequency channels. A plurality of guard sub-carriers between adjacent frequenc y channels are aligned and identified for data transmission in a pre-defined ph ysical resource unit. The identified guard sub-carriers do not overlap with normal da ta sub-carriers of the radio signals transmitted through the adja cent frequency channels. At least one of the identified guard sub-carriers is reserved as NULL sub- carrier. A flexible multi-carrier transceiver architecture is also provided in a multi-carrier OFDM system. Different multi-carrier and/or MIMO/SISO data transmission schemes are implemented by adaptively reconfigure same hardware modules including common MAC layer module, physical layer entities, and RF entities. Furthermore, the flexible multi-carrier tr ansceiver architecture can be used to support data transmission over guard sub-carriers.