Block Repeating Spread Diversity Signal Transmission
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Solution Overview
Problem
Existing broadband wireless communication systems face challenges with multipath interference and complex equalization in traditional multiple access modes, leading to reduced signal demodulation performance and increased system complexity, especially in co-frequency networking scenarios where interference between adjacent cells degrades communication performance at the cell edge.
Innovation Solution
The method involves performing weighting and repeating modulation on data blocks using a weighting factor sequence to create repeated block units, which are then mapped to specified time-frequency locations for transmission, allowing for flexible resource allocation and interference control, and employing block repeat transmission to coordinate system resources and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional time domain equalization is employed to overcome multipath interference in broadband systems, then signal demodulation performance can be improved, but the complexity of the equalization algorithm and system implementation is greatly increased due to the large number of multipaths and sufficient taps required
Solution Approach 1:
The patent transforms the equalization problem from the time domain to the frequency domain by using OFDM modulation. In the frequency domain, multipath interference is converted into simple complex multiplication, which can be easily compensated. This dimensional transformation avoids the need for complex time domain equalization filters with many taps, thereby reducing algorithm complexity while maintaining signal demodulation performance.
2Device complexity
If OFDM mode is employed to alleviate inter-symbol interference and avoid complex equalizers, then system performance can be improved and equalization complexity reduced, but frequency spectrum resources cannot be maximally utilized due to guard frequency bands required between adjacent sub-channels
Solution Approach 1:
The patent converts the harmful effect of multipath interference into a beneficial feature by using it to achieve orthogonal frequency division multiplexing. The multipath delays that cause intersymbol interference are transformed into orthogonal subcarriers in the frequency domain, where they become useful for increasing spectral efficiency. This allows adjacent subchannels to overlap in frequency without interference, maximizing spectrum utilization.
3Reliability
If traditional FDMA mode is employed to divide frequency bands for parallel data transmission, then interference between users can be reduced, but frequency spectrum resources cannot be maximally utilized due to guard frequency bands between adjacent sub-channels
Solution Approach 1:
The patent changes the fundamental parameter of frequency allocation by introducing orthogonality conditions between subcarriers. Instead of allocating non-overlapping frequency bands with guard bands, the system uses orthogonal frequency division multiplexing where subcarriers are spaced at intervals of 1/T (where T is the symbol duration). This parameter change allows frequency spectra to overlap while maintaining zero interference through orthogonality, thereby maximizing spectrum utilization while controlling interference.
Data Source
AI summary
A method, apparatus and system for transmitting signal, the method includes: using the weighting factor sequence, processing weighting repeating modulation for the basic cell block mapped by the data symbol block at the sending end, and obtaining a plurality of the repeating cell blocks corresponding to the said basic cell block; the sending end maps each repeating cell block to the appointed time-frequency position respectively, then sends the signals in the said time-frequency position; and the receiving end demodulates the plurality of data symbol blocks from the blocks, and incorporates the plurality of data symbol blocks; the said receiving end demodulates the incorporated data symbol blocks, and generates the received data. This scheme can be called for short as the block repeating spread diversity transmission technology, it is based on the information symbol in the time-frequency domain two-dimensional grid point. This scheme doesn't restrict the modulating signal generation manner at bottom, it can form a new multiple address/multiple path transmission scheme, and can be incorporated with the other key technologies in the existing mobile communication.