Multi-Modulation Transmitter for Concurrent OFDM and Single-Carrier Transmission
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Solution Overview
Problem
Current wireless communication standards face challenges in supporting concurrent operation of high-data-rate and low-data-rate devices, such as IoT devices, due to interference and inefficient spectrum usage, particularly in unlicensed bands like the 2.4 GHz ISM band, where existing technologies like Bluetooth and IEEE 802.11 struggle to provide adequate coverage and efficiency.
Innovation Solution
A multi-modulation transmitter that maps data to mutually orthogonal subcarrier signals using different modulation schemes, including OFDM and single-carrier schemes, allowing for concurrent transmission to multiple receivers, with a cyclic prefix adjustment to ensure compatibility and orthogonality between signals, enabling the reuse of existing hardware and improving spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If time division multiplexing is used to coordinate different systems, then interference between systems is reduced, but spectrum efficiency deteriorates due to longer channel occupation time
Solution Approach 1:
The patent segments the channel into multiple orthogonal subcarriers, allowing different modulation schemes to operate simultaneously on different subcarriers without interfering with each other. This eliminates the need for time division multiplexing while maintaining spectral efficiency, as multiple data streams are transmitted in parallel across the frequency spectrum.
Solution Approach 2:
The patent transitions from time-based coordination (TDM) to frequency-based coordination by utilizing the frequency dimension. Different modulation schemes are assigned to different subcarriers in the frequency domain, enabling concurrent transmission without temporal separation and thereby improving spectrum efficiency.
2Length of stationary object
If bit rate is reduced to increase coverage range, then coverage is improved, but transmission time increases causing channel congestion
Solution Approach 1:
The patent segments the transmission into multiple parallel subcarriers, each carrying a portion of the data. This allows the total data to be transmitted simultaneously across multiple frequency channels, reducing the overall transmission time while maintaining extended coverage through lower per-subcarrier bit rates.
Solution Approach 2:
The patent combines multiple subcarrier transmissions into a single multicarrier signal that provides both extended coverage and reduced transmission time. By merging parallel transmissions across frequency diverse subcarriers, the system achieves the benefits of both low bit rate (coverage) and parallel transmission (time reduction).
3Reliability
If separate systems are used for high-data-rate and low-data-rate applications, then each system can be optimized, but device complexity and cost increase
Solution Approach 1:
The patent implements a universal transmitter that can simultaneously support both high-data-rate and low-data-rate applications using a single multicarrier platform. By configuring different subcarriers with appropriate modulation schemes, the system provides multi-functionality without requiring separate dedicated systems, thereby reducing device complexity and cost.
Solution Approach 2:
The patent employs dynamic modulation scheme selection for different subcarriers based on channel conditions and service requirements. This dynamic adaptation allows a single system to optimize performance for different data rate requirements without being statically configured for a specific application type.
Data Source
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AI summary
The disclosure relates to a multi-modulation transmitter (40) configured to transmit a multicarrier signal to multiple different receivers, wherein at least one of the receivers is a receiver using a modulation scheme other than Orthogonal Frequency-Division Multiplexing, OFDM. The multi-modulation transmitter (40) comprises a data mapping unit (41) configured to map data targeting the different receivers to mutually orthogonal subcarrier signals, in accordance with the respective modulation schemes of the different receivers. The multi-modulation transmitter (40) also comprises an Inverse Fast Fourier Transform, IFFT, unit (43) configured to transform the mutually orthogonal subcarrier signals to a multicarrier signal in the time domain. The multi-modulation transmitter (40) further 1comprises a cyclic prefix unit (45) configured to determine a Cyclic Prefix, CP, length of the multicarrier signal based on a symbol rate of the receiver using a modulation scheme other than OFDM; and to insert the determined Cyclic Prefix in the multicarrier signal. The multi-modulation transmitter (40) additionally comprises a radio unit (47) configured to transmit the multicarrier signal to the multiple different receivers. The disclosure also relates to corresponding methods and to a receiver for receiving data transmitted by the multi- modulation transmitter.