Chirp-Spread Modulation Diversity for Wireless Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems require special reception devices with deinterleavers and error correction code-decoding means to achieve transmission diversity, limiting their applicability to general reception devices.
Innovation Solution
A wireless communication system that uses spread modulation with appropriate frequency offsets or delays to achieve diversity effects without the need for an interleaver or error correction code, utilizing a general reception device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency offset transmission diversity method is used, then transmission quality is improved, but reception device complexity increases due to requiring deinterleaver and error correction code-decoding means
Solution Approach 1:
The invention extracts and removes the complex deinterleaver and error correction code-decoding means from the reception device configuration. Instead, it uses a simple frequency offset application in the transmission phase combined with spread modulation, allowing general reception devices to achieve diversity effect without additional complex components.
Solution Approach 2:
The invention changes the approach from requiring complex reception processing to applying frequency offset parameters during transmission. By modifying the transmission side to apply different frequency offsets to multiple antennas and using spread modulation, the system achieves diversity without increasing reception device complexity.
2Reliability
If special reception device with deinterleaver and error correction code is used, then diversity effect is achieved, but system applicability deteriorates
Solution Approach 1:
The invention makes the diversity system universal by designing it to work with general reception devices that do not require special components like deinterleavers or error correction decoders. The frequency offset-based diversity combined with spread modulation can be applied across different wireless communication systems and devices, greatly expanding system applicability.
3Device complexity
If time diversity is used with long period of level fluctuation, then transmission is simplified, but diversity effect is reduced due to high correlation between paths
Solution Approach 1:
The invention transitions from time-based diversity to frequency-based diversity by applying different frequency offsets to signals from different antennas. This dimensional change from time domain to frequency domain allows the system to achieve diversity effect regardless of the time period of level fluctuation, maintaining effectiveness even when time diversity would fail due to high correlation.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A transmission device includes a modulation unit that performs chirp-spread modulation on an input information series to generate a modulation signal; a delay unit that provides, to a plurality of modulation signals obtained by duplicating the modulation signal generated by the modulation unit, delays having lengths different from each other, a difference between the delays being an integral multiple of a reciprocal of a bandwidth of the modulation signal; and a plurality of transmission antennas that transmit the plurality of modulation signals, respectively, to which the delays are provided by the delay unit.