MC-OOK Transmitter Using PIE for Passive Receiver Power
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Solution Overview
Problem
Passive receivers, which lack an independent power source and energy storage, struggle to operate during long periods of zero transmission in conventional On-Off Keying (OOK) modulation, as they cannot extract energy when the RF signal is off.
Innovation Solution
Implementing Pulse Interval Encoding (PIE) in a transmitter to ensure that passive receivers receive power even during zero transmissions by encoding data to include power intervals, using Multi-Carrier On-Off Keying (MC-OOK) modulation and OFDM modulation, ensuring at least partial power delivery during zero periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional On-Off Keying (OOK) modulation is used, then data transmission is achieved through simple amplitude modulation, but passive receivers cannot extract energy during long periods of zeros (OFF states)
Solution Approach 1:
The patent applies periodic action by introducing regular power delivery intervals through Pulse Interval Encoding (PIE). Instead of continuous OFF states, the system transmits power periodically even during zero data transmission periods. This ensures passive receivers can continuously extract energy and maintain operation, resolving the contradiction between simple OOK modulation and reliable passive receiver operation during zero transmission periods
Solution Approach 2:
The patent implements continuity of useful action by ensuring continuous power delivery to the passive receiver through PIE. The encoder inserts power intervals that maintain continuous energy transmission, eliminating the harmful effect of complete signal OFF periods. This allows the receiver to continuously harvest energy while the data transmission alternates between ON and OFF states, resolving the contradiction between data encoding requirements and continuous receiver operation
2Reliability
If Pulse Interval Encoding (PIE) is applied to ensure continuous power delivery, then passive receiver operation is maintained, but data decoding complexity increases due to threshold determination requirements
Solution Approach 1:
The patent uses an intermediary approach by introducing a dedicated power interval encoding layer between the data source and the physical transmission layer. The PIE encoder acts as an intermediary that translates data bits into power-delivery patterns, while the receiver's envelope detector serves as an intermediary that extracts both data and power information. This intermediary structure resolves the contradiction by providing a systematic method for power delivery that, while adding some decoding complexity, enables reliable continuous operation of passive receivers
Data Source
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AI summary
Thereis provided a transmitter (4) configured to transmit a message m = 0,1, ... , 2B - 1 from an input bit vector b comprising B input bits bi through a communication channel, the transmitter comprising: - an encoding unit (101) comprising an encoder (1010) configured to encode the B bits on the input bit vector, which provides C coded bits forming an encoded vector c; - A waveform modulation unit (102) configured to modulate the C coded bits delivered by the encoding unit (101) onto L consecutive OFDM symbols, each carrying M OOK symbols, M corresponding to the number of OOK symbols per OFDM symbol; - a resource mapping unit (104) configured to map the modulated signal delivered by the waveform modulation unit to frequency-domain resources Xm of N sub-carriers; - an OFDM modulation unit (105) configured to apply OFDM modulation to the resulting signal Xm, which provides a time-domain base-band signal xm(t), the transmitter (4) being configured to send a OFDM transmission derived from the signal xm(t) determined by the OFDM modulation unit (105) on sub-carriers, using one or more transmit antennas, wherein said OFDM transmission comprises one or more OOK symbols and OFDM symbols, wherein the encoding unit (101) further comprises a Pulse Interval Coding (PIE) unit configured to apply a Pulse Interval Encoding (PIE) to the coded bits delivered by the encoder (1010) to map one PIE pulse to one OOK symbol.