Wake-Up Signal Transmitter With MC-OOK Modulation
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Solution Overview
Problem
Current wake-up signal designs for 5G NR systems are inefficient in transmitting multiple bits per OFDM symbol, leading to long transmission durations and resource wastage, while also increasing receiver complexity and power consumption.
Innovation Solution
A wireless device with a transmitter configured to split input bits into vertical and horizontal components, applying Multi-Carrier On-Off Keying (MC-OOK) modulation and Discrete Fourier Transform (DFT) precoding to enable transmission of multiple bits per symbol, maintaining low-power receiver capabilities and increasing spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wake-up signal designs transmit one bit per OFDM symbol, then receiver complexity and power consumption are kept low, but transmission duration becomes long and spectral efficiency decreases
Solution Approach 1:
The input bit stream is segmented into multiple independent bit streams, each modulated onto a separate carrier frequency using MC-OOK. This allows parallel transmission of multiple bits per OFDM symbol, improving spectral efficiency while keeping each individual modulation simple for low-complexity reception
Solution Approach 2:
The patent transitions from single-carrier to multi-carrier modulation, adding the frequency dimension to the transmission. By distributing bits across multiple carrier frequencies, the system achieves higher spectral efficiency without proportionally increasing receiver complexity, as envelope detection can still be used
2Duration of action of moving object
If wake-up signal transmission uses traditional modulation schemes, then implementation is simple, but transmission duration increases and resources are wasted
Solution Approach 1:
The patent changes the modulation parameter from 1 bit/symbol to multiple bits per symbol by employing MC-OOK across K carrier frequencies. This parameter change reduces the number of symbols needed for transmitting a given amount of data, thereby reducing transmission duration and associated resource wastage
3Productivity
If multiple bits per symbol transmission is implemented without MC-OOK, then spectral efficiency improves, but receiver power consumption increases
Solution Approach 1:
The patent employs envelope detection, a self-service receiving mechanism that does not require complex coherent demodulation or carrier phase recovery. This allows the receiver to decode multiple bits per symbol from the MC-OOK modulated signal while maintaining low power consumption, as the envelope detector can be implemented with simple circuitry
Data Source
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AI summary
There is provided a wireless device comprising a transmitter (4) for transmitting a Wake-Up Signal (WUS) message m = 0,1, ..., 2B - 1 in a communication system (100), the transmitter (4) comprising : - a splitter (400) to split the input message m into Bv bits and Bh bits; - A vertical encoder (402) to encode the Bv bits into encoded bits c comprising elements ci; - a Multi-Carrier On-Off Keying (MC-OOK) modulator (42) to apply a MC-OOK modulation to the encoded bits c, which provides MC-OOK modulated signals sl,mv for the message m, - a horizontal encoder (404) to encode the Bh bits into an horizontal codeword wmh=w1,mh,w2,mh,…,wL,mh, - a combiner (14) to combine the MC-OOK modulated signals sl,mv with the horizontal codewords wl,mh, - a Discrete Fourier Transform (DFT) precoder (44) applying DFT-precoding to the combined sequence sl,m, - a single or multicarrier modulator (46) applying single or multicarrier modulation to the resulting signal Sm output by the DFT-precoder (44), the MC-OOK modulator (42) mapping a ON-signal a comprising KB elements to each element sl,mv of the MC-OOK modulated signal sm whenever the corresponding encoded input bit ci is equal to one, and a value zero otherwise.