A method for a wake up radio

Abstract

A method for providing a user equipment (20) main radio (21) to be activated by a wake up signal, performed by a wake up radio (10) provided to the user equipment (20) comprising the steps of detecting carrier signals having energy in a defined channel band from continuously listened carrier signals by an envelope detector (112), generating a chirp to modulate the detected signal, modulating the detected signal by a correlator (121) with defined chirp spreading factors (SF) according to the chirp, detecting peak amplitudes with a peak detector (122) to determine that the modulated signals are modulated according to a defined spreading factor, demodulating the carrier signal embedded in modulated frequency-shifted chirps with a synchronization mechanism (131), detecting the information carried by the demodulated signal using the fast fourier transform method, generating a trigger signal to wake up the main radio (21) if the information carried by the demodulated signal is found to be identical to a reference information, transmitting the trigger signal to the main radio (21).

Description

[0001] DESCRIPTION

[0002] A METHOD FOR A WAKE UP RADIO

[0003] TECHNICAL FIELD

[0004] The invention relates to a method for providing a user equipment main radio to be activated by a wake up signal, accomplished by a wake up radio provided to said user equipment.

[0005] BACKGROUND

[0006] Present 5G User Equipment (UE) demonstrates high power consumption, requiring frequent recharging, particularly within a few hours for smartphones and just days for resource-limited sensors. This challenge is particularly significant for devices with small batteries or those lacking convenient access to charging facilities, such as wearables and remote sensors. While prolonged periods of Discontinuous Reception (eDRX) can provide certain power-saving benefits, the associated latency drawbacks pose significant challenges for time-sensitive applications like fire detection and industrial automation.

[0007] 3rd Generation Partnership Project (3GPP) Release 18 seeks to overcome existing limitations by introducing an innovative ultra-low power wake-up mechanism. Departing from the conventional continuous polling approach, this new paradigm enables User Equipment (UE) to enter a deep sleep state and be awakened by a dedicated "Wake-Up Signal" (WUS) transmitted by the network. This transformative solution involves the use of a separate, ultra-low power Wake-Up Receiver (WUR) distinct from the main radio that consumes substantial data. Essentially, it employs a sentinel to safeguard the device's valuable energy reserves.

[0008] The design of the Wake-Up Signal (WUS) itself holds great significance, influencing both power consumption and the reliable detection capabilities of the compact Wake-Up Receiver (WUR). The primary goal is to develop optimal WUS / WUR solutions customized for power-sensitive UEs, including internet of things (loT) sensors and wearables, yielding substantial benefits beyond the power-saving methods introduced in Rel-15 / 16 / 17. Importantly, this initiative extends its impact beyond these specific use cases, encompassing potential applications in areas such as XR glasses and smart homes.

[0009] This initiative isn't merely another incremental tweak; it seeks to revolutionize UE energy efficiency, delivering transformative power savings compared to past releases. Of course, seamless compatibility with legacy UEs and rigorous performance evaluation remain unyielding priorities. In essence, Rel-18 embarks on a quest to unlock the true potential of UE energy efficiency, where slumbering devices awaken only to the whisper of a targeted WUS, ushering in a new era of sustainable and performant 5G connectivity.

[0010] WuS are already deployed in Wi-Fi technology under the IEEE 802.11 ba Wake-Up Radio (WuR) standard, where On-Off keying (OOK) modulation is used along with OFDM. The WuS in Wi-Fi incorporates the use of 312.5 KHz subcarriers in a 4 MHz bandwidth. For the WuR part, it functions in a defined periodic cycle reception mode which requires a beacon transmitted from the access point (AP) to synchronize the WuR to the AP radio.

[0011] Other technologies are presented as possible candidates for WuR. First the RF envelope detection technique which can be with or without intermediate frequency (IF) detection level. Frequency shift keying (FSK), or MC-FSK was also proposed to establish more detection accuracy. Finally, the classical OFDM with OOK can be a potential candidate with different subcarrier sequence implementation.

[0012] The invention with application number US202217935099 discloses a wake-up signal (WUS) communication technology for 5G user equipment (UE). The UE can identify a WUS resource set with configurable repetition level, associating WUS with specific physical resource blocks and OFDM symbols. Network access mode (NAM) transition from power-saving mode (PSM) is triggered upon WUS detection in the resource set. This design optimizes 5G UE energy efficiency and signaling.

[0013] The invention with application number US11503541 B2 discloses methods for transmitting and receiving wake-up signals in wireless communication. A network node transmits the signal over a dedicated bandwidth determined by the receiver's wake-up radio frequency error. Each receiver, equipped with a wake-up radio, wakes upon detecting the signal within this bandwidth. To establish this bandwidth, the receiver transmits its maximum frequency error to the network node, enabling precise wake-up signal transmission. The technology is based on OOK modulation of WuS signal in frequency domain by multiplexing the WuS signal using OFDMA along with data, this concurrent transmission of the WUS and data also provides a co-existence mechanism for the WUR approach with legacy approaches (e.g. in IEEE 802.11 ).

[0014] The invention with application number US11503541 B2 discloses encompasses various wireless communication techniques. One aspect involves a user equipment (UE) monitoring a downlink control channel within a specific bandwidth part (out of several options) with its associated periodicity. Based on received downlink control information (DCI) in the control channel, the UE may selectively switch to a different bandwidth part with a shorter monitoring periodicity. Additional aspects are disclosed.

[0015] The invention with application number WO2023214769A1 discloses a two-stage wake-up receiver enabling robust, low-power signal acquisition. A Stage 1 correlator initially detects a primary wake-up code within a defined preamble. Upon successful detection, a Stage 2 correlator performs joint correlation across the preamble and an extension period for enhanced discrimination and identification of a secondary wake-up code. This staged approach optimizes power consumption and reliability for wake-up signal recognition in resource-constrained applications.

[0016] All the problems mentioned above have made it necessary to make an innovation in the relevant technical field as a result.

[0017] BRIEF DESCRIPTION OF THE INVENTION

[0018] The present invention relates to a wake up radio to eliminate the above-mentioned disadvantages and bring new advantages to the relevant technical field. An object of the invention is providing a method that enables the main radio provided to the user equipment to be triggered for a defined wake up signal.

[0019] Another object of the invention is providing a wake up radio with increased power efficiency.

[0020] To achieve all the objects mentioned above and that will emerge from the following detailed description, the present invention relates to a method for providing a user equipment main radio to be activated by a wake up signal (WUS), performed by a wake up radio (WUR) provided to the user equipment. Accordingly, it comprises steps of: detecting carrier signals having energy in a defined channel band from continuously listened carrier signals by an envelope detector, generating a chirp to modulate the detected signal, modulating the detected signal by a correlator with defined chirp spreading factors (SF) according to the chirp, detecting peak amplitudes with a peak detector to determine that the modulated signals are modulated according to a defined spreading factor, demodulating the carrier signal embedded in modulated frequency-shifted chirps with a synchronization mechanism, detecting the information carried by the demodulated signal with FFT, generating a trigger signal to wake up the main radio if the information carried by the demodulated signal is found to be identical to a reference information, transmitting the trigger signal to the main radio.

[0021] Another possible embodiment of the invention is characterized in that wherein it comprises the step of dropping signals that are not modulated by the SF defined according to the peak value detected by the peak detector.

[0022] Another possible embodiment of the invention is characterized in that wherein the correlation process applied in the correlator is performed with a continuous signal.

[0023] Another possible embodiment of the invention is characterized in that wherein the correlation process applied in the correlator is performed with a discrete signal. Another possible embodiment of the invention is characterized in that wherein the envelope detector is configured to detect the energy of the carrier signal by means of a passive circuit.

[0024] Another possible embodiment of the invention is characterized in that wherein the envelope detector is configured to detect the energy of the carrier signal by means of an active circuit.

[0025] Another possible embodiment of the invention is characterized in that wherein it comprises the step of amplifying the continuously listened carrier signals by an amplifier before the step of detecting the carrier signals with energy in a defined channel band from the continuously listened carrier signals by an envelope detector,

[0026] Another possible embodiment of the invention is characterized in that wherein it comprises the step of detecting carrier signals with energy in a defined channel band from continuously listened carrier signals by an envelope detector, and then step of passing, by means of a low pass filter, signals within the defined band from the signals detected by the envelope detector.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a drawing illustrating working stages of the wake up radio.

[0029] DETAILED DESCRIPTION OF THE INVENTION

[0030] In this detailed explanation, the subject matter is explained with references tp examples without forming any restrictive effect only in order to make the subject more understandable.

[0031] Referring to figure 1 , the invention relates to a method for providing a user equipment (20) main radio (21 ) to be activated by a wake up signal, accomplished by a wake up radio (10) provided to said user equipment (20). In the mentioned method, the received wake up signal is detected by passing through three stages and the main radio (21 ) is triggered. Thus the main radio (21 ) is triggered with increased accuracy.

[0032] Referring to figure 1 , in the first stage (1 1 ) of wake up radio (10) is provided to continuously listen to the carrier wake up signals. In the first stage (1 1 ), it is evaluated whether the carrier signals have the energy in the defined channel band. Thus, wake up radio (10) ensures that other stages are activated only on carrier signals of certain energy. Signals that are not present at an energy in the mentioned channel band are eliminated without examination. This provides power efficiency and high detection probability. In the first stage (1 1 ), the signal power of the wake up signals received from the environment is increased with a low noise amplifier (1 1 1 ) (LNA). As is well known in the art, low noise amplifier (1 1 1 ) is an amplifier that increases the signal power in an electronic circuit. When the signal is weak or in noisy environments, amplifying the signal can also increase the noise. The low noise amplifier (1 11 ) has the ability to amplify at low noise levels. Therefore, carrier signals are first passed through the low noise amplifier (1 11 ). Thus, even at low noise levels, the signal is accurately detected by amplification.

[0033] Carrier signals passing through the low noise amplifier (1 11 ) are transmitted to the envelope detector (112). Envelope detector (1 12) provides the energy of the signal to be obtained by monitoring the amplitude changes of the modulated carrier signals.

[0034] Depending on the complexity of the system, different types of wake-up radio circuits, including active circuit and passive circuit, can be used to monitor the signal through the envelope detector (1 12). Passive circuits minimize the power draw through simple envelope sensing or energy harvesting. The circuits mentioned prioritise efficiency. However, due to its noise sensitivity, it may encounter a higher rate of false alarms. Passive circuits are preferred for resource- constrained applications where occasional false wake-ups are acceptable. Active circuits feature advanced signal processing (correlation, matching filtering). Utilizing special wake-up receivers, these circuits achieve strong detection accuracy with low false alarms. However, using active circuits in applications requiring high data rates and uninterrupted connection may cause increased power consumption and circuit complexity. By using active circuit or passive circuit, various system requirements and performance trade-offs are met.

[0035] Referring to figure 1 , the signal passing through the envelope detector (112) is passed through a low pass filter (113). As is well known in the art, low pass filter (113) ensures that signals below a certain frequency are passed and signals above a certain frequency are blocked. Thus, only signals with predefined frequency values are passed to the second stage (12).

[0036] Referring to figure 1 , a chirp signal is generated to modulate the carrier signal that passes to the second stage (12). Thus, the frequency of the carrier signal is changed according to time. As is well known in the art, chirp means that the frequency of a signal continuously increases or decreases with time. This means that the amplitude or phase of a signal does not change with time, but its frequency does. Chirp is generally generated by applying a modulation process to a carrier signal. This modulation process creates the chirp effect by changing the frequency of the signal regularly. The carrier signal is modulated with a correlator (121) with chirp spreading factors (SF) defined according to the said chirp signal.

[0037] Referring to figure 1 , chirp spreading factor expresses the rate of change of the frequency of the chirp signal with time. This factor determines how the frequency of the chirp signal changes with time and the general characteristics of the chirp signal. The chirp spreading factor is usually expressed as a numerical value that expresses how much the frequency of the chirp signal changes per unit time. For example, if the frequency of a chirp signal increases by 100 kHz / sec with time, the chirp spreading factor is expressed as 100 kHz / sec. The correlator (121 ) enables the comparison of the chirp signal with defined spreading factor according to the chirp signal produced with the carrier signal, thus enabling the similarity relationship between the two signals to be determined. The correlator (121 ) enables the change in the frequency of the chirp signal to be determined by measuring the frequency difference between the chirp signal and the carrier signal. This frequency difference is used to calculate the chirp spread factor. In a possible embodiment of the invention, it is preferred to use an analog correlator (121 ) as a correlator (121 ). In another possible embodiment of the invention, it is preferred to use a digital correlator (121 ) as a correlator (121 ).

[0038] In order to detect the signal modulated with a predefined spreading factor from the carrier signals modulated with the correlator (121 ), the peak amplitude of the signal is detected with a peak detector (122). Peak detector (122) allows detecting the maximum amplitude of a signal. By receiving the modulated carrier signal coming out of the correlator (121) to the peak detector (122), changes in the amplitude of the carrier signal are measured. A decision is made by comparing this change with the defined spreading factor. If the carrier signal is modulated with a defined spreading factor, it is decided to pass it to the third stage (13). If the carrier signal is not modulated with a defined spreading factor, a discard decision is made.

[0039] Referring to figure 1 , in the third stage (13), the carrier signal embedded in the modulated frequency-shifted chirps is demodulated by a synchronization mechanism (131 ). This enables accurate detection of frequency changes of the carrier signal and which digital data state these frequency changes represent. With the fast fourier transform (FFT) of the carrier signal demodulated by the synchronization mechanism (131 ), the frequency components of the signal, the carried data and the properties of the signal are determined. Fast fourier transform enables analysis and processing of demodulated signals. If the information carried by the demodulated signal is found to be identical to a reference information, a trigger signal is generated to wake up the main radio (21 ). The generated trigger signal is transmitted to the main radio (21 ). Thus, it is ensured that the main radio (21 ) is activated only on specified wake up signals. This allows power efficiency to be increased. In addition, the main radio (21) is triggered only on the defined wake up signal.

[0040] In order to achieve all the objects stated above and arising from the above detailed description, the present invention relates to a method for providing a user equipment (20) main radio (21 ) to be activated by a wake signal, accomplished by a wake up radio (10) provided to said user equipment (20). This method is characterized by including the following steps; • detecting carrier signals having energy in a defined channel band from continuously listened carrier signals by an envelope detector (112),

[0041] • generating a chirp to modulate the detected signal,

[0042] • modulating the detected signal by a correlator (121 ) with defined chirp spreading factors (SF) according to the chirp

[0043] • detecting the peak amplitude with a peak detector (122) to determine that the modulated signals are modulated according to a defined spreading factor,

[0044] • demodulating the carrier signal embedded in modulated frequency-shifted chirps with a synchronization mechanism (131 ),

[0045] • detecting the information carried by the demodulated signal using the fast fourier transform method,

[0046] • generating a trigger signal to wake up the main radio (21) if the information carried by the demodulated signal is found to be identical to a reference information,

[0047] • transmitting the trigger signal to the main radio (21 ).

[0048] A possible embodiment of the invention is that this method includes the step of dropping signals that are not modulated by the spreading factor defined according to the peak value detected by the peak detector (122).

[0049] In another embodiment of the invention, the method includes the step of the correlation process applied in the correlator (121 ) is performed with a continuous signal.

[0050] In another embodiment of the invention, the method includes the step of the correlation process applied in the correlator (121 ) is performed with a discrete signal.

[0051] In another embodiment of the invention, the method includes the step of the envelope detector (112) is configured to detect the energy of the carrier signal by means of a passive circuit. In another embodiment of the invention, the method includes the step of the envelope detector (112) is configured to detect the energy of the carrier signal by means of an active circuit.

[0052] In another embodiment of the invention, the method includes the step of amplifying the continuously listened carrier signals by an amplifier before the step of detecting the carrier signals with energy in a defined channel band from the continuously listened carrier signals by an envelope detector (112).

[0053] In another embodiment of the invention, the method includes the step of detecting carrier signals with energy in a defined channel band from continuously listened carrier signals by an envelope detector (112), and then step of passing, by means of a low pass filter (113), signals within the defined band from the signals detected by the envelope detector (112).

[0054] In order to achieve all the objects stated above and arising from the above detailed description, the present invention relates to a system for enabling the activation of a user equipment (20) main radio (21 ) by a wake up signal. This system is characterized in that it comprises a wake up radio (10) configured to perform the method steps described above.

[0055] The scope of protection of the invention is specified in the attached claims and cannot be limited to those explained for sampling purposes in this detailed description. It is evident that a person skilled in the art may exhibit similar embodiments in light of the above-mentioned facts without drifting apart from the main theme of the invention.

[0056] REFERENCE NUMBERS GIVEN IN THE FIGURE

[0057] 10 Wake Up Radio

[0058] 11 First stage 111 Low noise amplifier

[0059] 112 Envelope detector

[0060] 113 Low pass filter

[0061] 12 Second stage

[0062] 121 Correlator 122 Peak detector

[0063] 13 Third stage

[0064] 131 Synchronization mechanism

[0065] 20 User equipment

[0066] 21 Main radio

Claims

CLAIMS1 . A method for providing a user equipment (20) main radio (21 ) to be activated by a wake up signal, performed by a wake up radio (10) provided to the user equipment (20) comprising the steps of- detecting carrier signals having energy in a defined channel band from continuously listened carrier signals by an envelope detector (112),- generating a chirp to modulate the detected signal,- modulating the detected signal by a correlator (121 ) with defined chirp spreading factors according to the chirp,- detecting peak amplitudes with a peak detector (122) to determine that the modulated signals are modulated according to a defined spreading factor,- demodulating the carrier signal embedded in modulated frequency- shifted chirps with a synchronization mechanism (131 ),- detecting the information carried by the demodulated signal using the fast fourier transform method,- generating a trigger signal to wake up the main radio (21 ) if the information carried by the demodulated signal is found to be identical to a reference information,- transmitting the trigger signal to the main radio (21 ).

2. The method of claim 1 , wherein it comprises the step of dropping signals that are not modulated by the spreading factor defined according to the peak value detected by the peak detector (122).

3. The method of claim 1 , wherein the correlation process applied in the correlator (121 ) is performed with a continuous signal.

4. The method of claim 1 , wherein the correlation process applied in the correlator (121 ) is performed with a discrete signal.

5. The method of claim 1 , wherein the envelope detector (1 12) is configured to detect the energy of the carrier signal by means of a passive circuit.

6. The method of claim 1 , wherein the envelope detector (112) is configured to detect the energy of the carrier signal by means of an active circuit.

7. The method of claim 1 , wherein it comprises the step of amplifying the continuously listened carrier signals by an amplifier before the step of detecting the carrier signals with energy in a defined channel band from the continuously listened carrier signals by an envelope detector (112).

8. The method of claim 1 , wherein it comprises the step of detecting carrier signals with energy in a defined channel band from continuously listened carrier signals by an envelope detector (112), and then step of passing, by means of a low pass filter (113), signals within the defined band from the signals detected by the envelope detector (112).

9. A system for enabling the activation of a user equipment (20) main radio (21 ) by a wake up signal, characterized in that; it comprises a wake up radio (10) configured to perform the steps of a method as in one of the preceding claims.

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