Methods and signalling for operating a-IOT devices

Abstract

Methods and signaling for operating A-IoT devices are described In one implementation, a method of operating A-IoT devices comprises monitoring, by a first node, for a paging signal. The first node determines initiation of access procedure. The first node transmits a first signal comprising at least one of a randomly generated identity, a feedback related to the paging signal, at least one value, and a message type. The first node monitors for a random ID response message, and receives the random ID response message. The first node initiates transmission of a second signal when the randomly generated identity is present in the random ID response message, or a frequency index associated with the random ID response message matches with a value of the frequency resource used for transmission of the first signal.

Description

METHODS AND SIGNALLING FOR OPERATING A-IOT DEVICES FIELD OF THE INVENTION

[0001] The present invention relates to method of operating A-IoT devices, and more particularly to multiplexing techniques and methods to improve reliability of communication.BACKGROUND OF THE INVENTION

[0002] In recent years, reduced capability devices with ultra-low power consumption, minimum maintenance cost, and long-life span have attracted much attention in the wireless communication world. A massive number of such devices are expected to be deployed and connected to the network to improve productivity, efficiency and increase the comforts of life. Further reduction of size, complexity, and power consumption of such devices can enable the deployment of tens or even hundreds of billion devices for various applications and provide added value across the entire value chain. Further, it is impossible to power all such devices by battery that needs to be replaced or recharged manually, which leads to high maintenance cost, serious environmental issues, and even safety hazards in some use cases (e.g., wireless sensor in electric power and petroleum industry). Therefore, energy harvesting can be a potential option to power such devices, where the energy can be harvested using radio waves, light, motion, heat, or any other power source that could be seen suitable.

[0003] Radio frequency identity (RFID) is a well-known technology which has the above-mentioned features. RFID supporting battery less tags has been used in many kinds of applications, such as retail and logistics. RFID has been trialled for manufacturing logistics. However, manual scanning is needed due to the poor effective communication range of a few meters, which leads to labour intensive and time-consuming operations, or RFID portals / gates which leads to costly deployments. Moreover, the lack of interference management scheme results in severe interference between RFID readers and capacity problems, especially in case of dense deployment. Therefore, it is hard to support large-scale networks with seamless coverage for RFID.

[0004] Ambient loT (A-IoT) devices are an alternate class of reduced capability devices in cellular technology. The A-IoT devices are managed by the existing cellular infrastructureusing the licensed spectrum, thereby increasing the effectiveness of communication, device density and range significantly. Further, it avoids manual scanning and interference issues. An A-IoT device is expected to support communication range of tens of meters to few hundred meters, depending on capability of device and deployment scenarios. Further, the cellular BS can be reused as readers to minimize the deployment cost and cellular bands / technologies can be reused to improve performance. Furthermore, a network which scales with the number of devices or readers should also be supported for practical deployments, and it should be resilient to e.g., interference between readers to avoid the cost of complicated network planning. The use cases for A-IoT devices can be broadly classified into four categories such as tag identification, sensor monitoring, target tracking and actuator. Typical scenarios such as automated warehousing, automobile manufacturing, and medical instruments inventory management etc. Sensor monitor refers to the detection of KPI data in the surrounding environment through sensors, and then, using these data to make corresponding judgments to achieve corresponding detection purposes, including danger, disaster, and health detection and data reporting. Target tracking is an application that uses the network to obtain device location information to locate targets, including item finding, positioning and tracking, etc. An actuator is a device that converts energy into motion. It does this by taking an electrical signal and combining it with an energy source. An actuator comes in a few different guises, including Pneumatic, Hydraulic, Electric, Thermal and Magnetic.

[0005] The A-IoT devices can be classified into following categories based on the capability to backscatter or transmit signal:i. Catl: Device with b ackscattering (BSc) capability and Control unit (CU) to receive control information (CI) from the reader / network. The CI can be used to control the operation of the device. E.g., initial attachment, synchronization, the frequency of operation, the scheduling for downlink (DL) / uplink (UL), etc. The device operates in certain bands depending on circuitry or control, receives CI in DL and backscatter (BSc) signals in UL based on CI. The BSc signal can be a modulated and / or amplified version of the incoming signal.ii. Cat2: Device with transmission capability and CU to receive CI. These devices can generate signal and transmit signal to reader / network based on CI. The transmitted signal can be modulated with information stored or measured by the device.

[0006] Deployment of A-IOT device can include following entities:i. A-IoT reader: The A-IoT reader, or simply reader, controls the operation of the A-IoT device. A reader can be handheld, mounted to infrastructure (e.g. base station (BS), user equipment (UE) etc. It may or may not be battery constrained (depending on the scenario) and can (but not necessarily need to) connect to an A-IoT server. The reader is responsible for managing communication with the A-IoT devices. The reader establishes connection with A-IoT device, sends commands / control, collects data from the A-IoT devices, and coordinates their activities. The A-IoT reader may be connected to a larger network or the internet, enabling data exchange with other systems or cloud services.ii. A-IoT device: The A-IoT device, or simply device, can be attached to any object, and can connect to a reader device with an A-IoT radio. The tag may not have any active connection to an A-IoT server. Any signal / information exchange between the A-IoT device and the server is via the reader device (e.g. A-IoT device signature, configuration, data reporting) and is controlled by the reader.iii. Carrier wave node: Catl A-IoT devices mainly work on the principle of backscatter communication. The backscatter transmitter reflects the carrier wave and modifies one or more characteristics (e.g., amplitude, phase, or center frequency) of the reflected signal according to the information bits stored in its memory. Communication via back scattering instead of active radiation reduces the RF frontend of the device to a single transistor switch, which minimizes the manufacturing cost as well as energy demands. The node which transmits carrier waves is known as carrier wave node (CWN). The carrier wave can be transmitted by the reader or an external node near to the A-IoT device. In the case of reader acting as CWN, the pathloss encountered by the backscattered wave is dependent on twice the distance between reader and the A-IoT device, which significantly reduces the coverage. Further, transmission of carrier wave and reception of backscattered signal happen simultaneously at the reader, demanding full duplex operation, resulting in self-interference and performance degradation. The carrier wave transmitted by the external node has the advantage of reduction in pathloss and increase in coverage as the CWN is near to the A-IoT device. Further, it reducesinterference at the reader as the reader is only receiving backscattered signal from the A-IoT device.

[0007] The A-IoT device derives energy to turn on the receiver, modulating, amplifying and backscattering / transmission circuitry using the energy harvesting mechanism. The energy harvesting can be performed using carrier wave provided externally using a CWN, RF signal, solar energy etc. Once the device has harvested enough energy it turns on the circuitry, modulates the carrier wave based on the stored value and back scatter modulated carrier wave to the reader. The energy remaining after backscattering can be stored in the device depending on the energy storing capability of the device. The energy harvesting process can be continuous or discontinuous. In continuous case, the device harvest energy continuously irrespective of whether communication with reader is initiated or ongoing, whereas in discontinuous case, the energy harvesting starts only when either the communication with reader is initiated or energy storage goes below certain threshold.

[0008] The existing techniques and mode of operation in cellular communication systems do not suit A-IoT devices, as the features of the A-IoT devices are quite different from the existing devices in cellular network. E.g., the power consumption of A-IoT devices is assumed to be in the range of 1 pW to a few hundreds of pW, whereas the existing cellular devices operates with peak power consumption of higher than lOmW. Therefore, new techniques and procedures, considering typical features of A-IoT devices like energy harvesting, backscattering, low power consumption, high connection density, etc., is essential to meet requirements of the targeted use cases and to ensure efficient deployment of the technology.

[0009] Multiplexing is an important aspect in effectively utilizing the resources, especially when the connection density is high, and the devices have lower capability. Configuring the resources according to the capability of the devices and performance requirements and switching the resources effectively across devices are key aspects in this regard. Further, power constrained devices can become unavailable in between the process and can lead to re-initiation of the whole process. It leads to wastage of resources and reduction in resource utilization. Therefore, designing the whole process to complete in short span of time and ensuring reliability in communication are essential when the devices are power constrained.OBJECTS OF THE INVENTION

[0010] A general objective of the present invention is to provide a method of signalling for operating Ambient-Internet-of-Things (A-IoT) devices.

[0011] Another objective of the present invention is to provide a method of multiplexing A-loT devices.SUMMARY OF THE INVENTION

[0012] The summary is provided to introduce a method of signalling for operating Ambient-Internet-of-Things (A-IoT) devices, and the method is further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0013] In one embodiment, the method of operating A-IoT devices comprises monitoring, by a first node, for a paging signal. The first node determines initiation of access procedure. The first node transmits a first signal comprising at least one of a randomly generated identity, a feedback related to the paging signal, at least one value, and a message type. The first node monitors for a random ID response message, and receives the random ID response message. The first node initiates transmission of a second signal when the randomly generated identity is present in the random ID response message, and / or a frequency index associated with the random ID response message matches with a value of the frequency resource used for transmission of the first signal.

[0014] In one aspect, monitoring comprises receiving the paging signal.

[0015] In one aspect, determining is based on a paging identity present in the paging signal.

[0016] In one aspect, the paging identity comprises at least one ofan identity of the first node,a type of the first node, andan indication to one of the first node or a group of nodes comprising the first node or a null.

[0017] In one aspect, the paging signal comprises at least one ofa paging identity,information about a type of the access procedure,scheduling information, andan identity of a second node transmitting the paging signal.

[0018] In one aspect, the type of the access procedure is at least one ofcontention based access procedure or contention free access procedure,inventory procedure,command procedure,sensing procedure, andpositioning procedure.

[0019] In one aspect, the paging identity comprises an identity of the first node when the type of the procedure is one ofcontention free procedure, andcommand procedure.

[0020] In one aspect, the scheduling information is for at least one of:transmission of the first signal;reception of system information; andreception of the random ID response message.

[0021] In one aspect, the scheduling information for transmission of the first signal comprises at least one ofnumber of access occasions,number of time resources in an access occasion,number of small frequency shift,information for selecting resources,number of repetitions,information about content of the first signal,a carrier frequency, andat least one value of small frequency shift.

[0022] In one aspect, the information about the content of the first signal comprises at least one ofthe randomly generated identity of the first node,feedback for the paging signal, andat least one value measured by the first node.

[0023] In one aspect, the information for selecting resources comprises at least one ofa start time of a timer,a step size for decrementing the timer,a time window for transmission of the first signal, andone of number of bits M and range of values for generating a random number to select the resource.

[0024] In one aspect, the scheduling information comprises at least one ofa pattern,a sequence, anda time window for monitoring for at least one of a system information and the random ID response message.

[0025] In one aspect, monitoring comprises at least one of:correlating using one of a pattern and a sequence;identifying one of the pattern and the sequence; andreceiving a type of signal.

[0026] In one aspect, one of the pattern and the sequence is predefined, or indicated in the paging signal.

[0027] In one aspect, identifying one of the pattern and the sequence indicate start of the reception, or end of the reception.

[0028] In one aspect, the type of signal comprises one ofthe paging signal,a trigger signal,the random ID response message,a feedback signal,a control signal, anda data signal.

[0029] In one aspect, monitoring is donewithin a time window, orafter a minimum time duration from one oftransmitting the first signal, andend of a time window configured for transmitting the first signal.

[0030] In one aspect, the time window is one ofa time difference between first and last resource configured for transmission of first signal, anda time difference between the minimum time duration and a maximum time duration, which are predefined.

[0031] In one aspect, the maximum time duration is between a transmission and subsequent reception.

[0032] In one aspect, the minimum time duration is predefined, and between a transmission and subsequent reception.

[0033] In one aspect, the randomly generated identity is generated using a random number represented using N bits.

[0034] In one aspect, the value of N is one of 8, 16 and 32.

[0035] In one aspect, transmitting comprises at least one ofmonitoring for a preamble,correlating using the preamble,transmitting the preamble indicating start of transmission, andtransmitting a postamble indicating end of transmission.

[0036] In one aspect, the at least one value isstored in the memory of the first node, ormeasured by the first node.

[0037] In one aspect, the frequency index associated with the random ID response message is one ofa frequency index indicated by the random ID response message, anda frequency resource of receiving the random ID response message.

[0038] In one aspect, the random ID response message comprises at least one ofa common control information, anda device specific control information.

[0039] In one aspect, the location of the device specific control information is obtained using the common control information.

[0040] In one aspect, the device specific control information is obtained by one of correlating using a sequence specific to the first node,descrambling of the possible device specific control information using the identity of the first node, andperforming CRC on the possible device specific control information using the identity of the first node.

[0041] In one aspect, the sequence is configured by the common control information or is predefined.

[0042] In one aspect, the random ID response message comprises at least one ofat least one identity,at least one frequency index,network information,multiplexing information, andscheduling information.

[0043] In one aspect, scheduling information comprises at least one ofscheduling for device specific control information,time resource for transmission of the second signal,carrier frequency for transmission of the second signal,value of small frequency shift for transmission of the second signal,value of amplification factor for the second signal,parameters related to repetition of the second signal, andinformation about content of the second signal.

[0044] In one aspect, the parameters related to repetition comprises at least one of number of repetition,type of repetition,resources for repetition,pattern of repetition, andnumber of square waves within a bit duration.

[0045] In one aspect, the information about the content of the second signal comprises at least one ofan identity of the first node,an energy status of the first node,a feedback for the random ID response message, andat least one value measured by the at least one first node.

[0046] In one aspect, the scheduling for device specific control information comprises at least one ofan identity of the first node,start of device specific control information for the first node in the random ID response message,length of the device specific control information for the first node, andan index of the block corresponding to the device specific control information in the random ID response message.

[0047] In one aspect, the multiplexing information comprises at least one ofa preamble for the first node for one of transmission and monitoring,a value of cyclic shift to apply to the preamble,at least one time resource for the first node for one of transmission and monitoring, and a time offset for the first node for one of transmission and monitoring.

[0048] In one aspect, the preamble comprises at least one of a pattern, and a sequence.

[0049] In one aspect, transmitting is performed after one of:detecting a preamble; anda time duration from a reference time instant.

[0050] In one aspect, the time duration is one of:predefined;configured in the random ID response message; andderived, by the first node, based on an identity of the first node.

[0051] In one aspect, the reference time instant is one of:end of time window for reception of random ID response message;start of the time window for transmission of the second signal; andtime instant of receiving one of the random ID response message and the preamble.

[0052] In one aspect, transmitting the first signal comprises randomly selecting an access occasion for transmission of the first signal from a set of access occasions, configured by the paging signal.

[0053] In one aspect, randomly selecting the access occasion comprises:generating a random number within a range; andselecting the access occasion corresponding to the random number.

[0054] In one aspect, the range is between zero and number of access occasions configured by the paging signal.

[0055] In one aspect, selecting is according to count down behavior. The countdown behaviour starts from receiving the paging message and continue until transmitting the first signal, or receiving a different paging signal.

[0056] In one aspect, the countdown behaviour comprisessetting the random number to a counter, andperforming one ofselecting an occasion next to the random number, when the value of the counter is less than a first value, anddecrementing the counter by the first value, when the value of the counter is more than or equal to the first value, and selecting the occasion next to the random number, when the value of the counter is less than the first value.

[0057] In one aspect, decrementing is performed on receiving a trigger signal, until the value of the counter is less than the first value.

[0058] In one aspect, selecting the occasion next to the random number is from the first value of resources triggered by one of the paging signal and a trigger signal.

[0059] In one aspect, the first value is the product of a number of small frequency shift for transmission of the first signal, and a number of time resources in an access occasion for transmission of the first signal.

[0060] In one aspect, receiving the paging signal comprises receiving a trigger signal indicating start of an access occasion.

[0061] In one aspect, the trigger signal corresponds to an access occasion for transmission of the first signal and activation of a first value of resources for transmission of the first signal.

[0062] In one aspect, the first value is the product of a number of small frequency shift for transmission of the first signal, and a number of time resources in an access occasion for transmission of the first signal.

[0063] In one aspect, the second signal comprises at least one ofan identity of the first node,a feedback for the random ID response message,energy status of the first node,scheduling request to allocate resources for transmission,at least one value measured by the first node,at least one value stored in the memory of the first node, andthe message type.

[0064] In one aspect, the message type is one ofa random ID message,a data message, anda control message.

[0065] In one aspect, the first node determines process failure when no random ID response message is received.

[0066] In one aspect, transmitting comprises performing small frequency shift by representing an information bit using P square-wave cycles per bit duration.

[0067] In one aspect, the value of P is randomly selected by the first node from a plurality of values.

[0068] In one aspect, the plurality of values are predefined, or configured in one of the paging signal and the random ID response message.

[0069] In one aspect, the at least one value of small frequency-shift is one ofan absolute value of small frequency shift,an index corresponding to a predefined set of small frequency-shift values, and number of square-wave cycles per bit duration.

[0070] In one embodiment, a method of operating Ambient-Intemet-of-Things (A-IoT) devices in a network comprises transmitting, by a second node, a paging signal. The second node receiving at least one first signal comprising at least one of at least one first identity, feedback related to the paging signal, at least one value, and a message type. The second node transmits at least one random ID response message comprising indication of successful completion of access procedure to at least one first node. The indication of successful completion of access procedure comprises at least one second identity from the at least one first identity and at least one frequency index. The second node receives at least one second signal from the at least one first node.

[0071] In one aspect, the at least one second identity is successfully received by the second node in the at least one first signal.

[0072] In one aspect, receiving the at least one first signal comprises at least one of determining the at least one second identity,determining at least one third signal comprising the at least one second identity, determining at least one small frequency shift associated with the at least one third signal, anddetermining the at least one frequency index corresponding to the small frequency shift.

[0073] In one aspect, the paging signal comprises at least one ofpaging identity,information about type of the access procedure,scheduling information, andidentity of the second node.

[0074] In one aspect, the paging identity select at least one third node to initiate access procedure.

[0075] In one aspect, the paging identity comprises identity of the at least one third node when the type of the access procedure is one ofcontention free procedure, andcommand procedure.

[0076] In one aspect, the type of the access procedure comprises at least one ofone of contention based access procedure and contention free access procedure, inventory procedure,command procedure,sensing procedure, andpositioning procedure.

[0077] In one aspect, the scheduling information is for at least one third node to at least one of transmit the at least one first signal,receive system information, andreceive the at least one random ID response message.

[0078] In one aspect, the scheduling information comprises at least one ofnumber of access occasions,number of time resources in an access occasion,number of small frequency shift,information for selecting resources,number of repetitions,indication of content of the at least one first signal,a carrier frequency,at least one value of small frequency shift,a pattern,a sequence, anda time window for at least one third node to monitor for at least one of a system information and the random ID response message.

[0079] In one aspect, the indication of the content of the at least one first signal comprises at least one ofa randomly generated identity of the at least one third node,an identity of the at least one third node,a feedback for the paging signal, andat least one value measured by the at least one third node.

[0080] In one aspect, information for selecting resources comprises at least one ofa start time of a timer,a step size for decrementing the timer,time window for the transmission of the at least one first signal, andone of number of bits M and range of values for generating a random number to select the resource.

[0081] In one aspect, the paging identity comprises at least one ofan identity of at least one third node,a type of the at least one third node, andan indication to at least one third node or a null.

[0082] In one aspect, the at least one first signal is received from at least one third node selected in the paging signal.

[0083] In one aspect, receiving comprises at least one ofmonitoring using one of pattern and a sequence;identifying one of the pattern and the sequence; andreceiving the type of signal.

[0084] In one aspect, the pattern and the sequence ispredefined, orconfigured, by the second node, using one of paging signal and the random ID response message.

[0085] In one aspect, identifying one of the pattern and the sequence indicate one of start of the reception, andend of the reception.

[0086] In one aspect, the type of signal comprises one ofthe at least one first signal,the at least one second signal,a data signal, anda control signal.

[0087] In one aspect, monitoring is at least one ofwithin a time window, andafter a minimum time duration from one ofend of a time window configured for transmitting the random ID response message, and transmitting one of the paging signal and the random ID response message.

[0088] In one aspect, the minimum time duration is predefined, and between a transmission and subsequent reception.

[0089] In one aspect, transmitting comprises at least one oftransmitting one of a first pattern and a first sequence indicating start of one of paging signal and random ID response message;transmitting one of a second pattern and a second sequence indicating end of one of paging signal and random ID response message;transmitting one of a third pattern or a third sequence to indicate start of one of first signal and second signal;transmitting type of signal; andtransmitting a trigger signal indicating start of an access occasion configured by the paging signal.

[0090] In one aspect, one of the first pattern, the first sequence, the second pattern, the second sequence, the third pattern and the third sequence is one ofpredefined, andconfigured, by the second node, using one of paging signal and the random ID response message.

[0091] In one aspect, the type of signal comprises one ofthe paging signal,a trigger signal,the random ID response message,a feedback signal,a control signal, anda data signal.

[0092] In one aspect, transmitting the at least one random ID response message is in a frequency resource, where at least one third signal is received.

[0093] In one aspect, the at least one random ID response message contains the at least one second identity received in the at least one third signal.

[0094] In one aspect, the at least one third signal is a subset of at least one first signal, which is successfully received by the at least one second node.

[0095] In one aspect, the at least one frequency index indicates the small frequency shift associated with one or more of the at least one first signal comprising the at least one second identity.

[0096] In one aspect, the at least one first identity is randomly generated using a random number represented using N bits.

[0097] In one aspect, the value of N is one of 8, 16 and 32.

[0098] In one aspect, the random ID response message further comprises at least one of a common control information,at least one device specific control information,network information,multiplexing information, andscheduling information.

[0099] In one aspect, the at least one device specific control information is at least one of applicable for one or more of the at least one first node; andscrambled using identity of one or more of the at least one first node.

[0100] In one aspect, scheduling information comprises at least one of scheduling for the at least one device specific control information,time resource for transmission of the second signal,carrier frequency for transmission of the second signal,value of small frequency shift for transmission of the second signal,value of amplification factor for the second signal,parameters related to repetition of the second signal, andinformation about content of the second signal.

[0101] In one aspect, the parameters related to repetition comprises at least one of number of repetition,type of repetition,resources for repetition,pattern of repetition, andnumber of square waves within a bit duration.

[0102] In one aspect, the information about the content of the at least one second signal comprises at least one ofan identity of the at least one first node,an energy status of the at least one first node,a feedback for the random ID response message, andat least one value measured by the at least one first node.

[0103] In one aspect, scheduling for the at least one device specific control information comprises at least one ofidentity of one or more of the at least one first node,preamble associated with the at least one device specific control information, start of the at least one device specific control information,length of the at least one device specific control information, andindex of the block corresponding to the at least one device specific control information.

[0104] In one aspect, the multiplexing information comprises at least one ofa preamble for the at least one first node for one of transmission and monitoring, a value of cyclic shift to apply to the preamble,at least one time resource for the at least one first node for one of transmission and monitoring, anda time offset for the at least one first node for one of transmission and monitoring.

[0105] In one aspect, the preamble comprises at least one of a pattern, and a sequence.

[0106] In one aspect, the trigger activates a first value of resources for transmission of the at least one first signal.

[0107] In one aspect, the first value is the product of a number of small frequency shift for transmission of the at least one first signal, and a number of time resources in an access occasion for transmission of the at least one first signal.

[0108] In one aspect, the second signal comprises at least one ofan identity of the at least one first node,a feedback for the at least one random ID response message,energy status of the at least one first node,scheduling request,at least one value measured by the at least one first node,at least one value stored in the memory of the at least one first node, andthe message type.

[0109] In one aspect, the message type is one ofa random ID message,a data message, anda control message.BRIEF DESCRIPTION OF THE DRAWINGS

[0110] Fig. 1 illustrates a timing diagram showing usage of random ID response message or random access response (RAR) as a common control signal for operating A-IoT devices.

[0111] Fig. 2 illustrates a method of using random ID response message or RAR as a device specific signal for operating A-IoT devices.

[0112] Fig.3a illustrates a method of multiplexing A-IoT devices using device specific preambles.

[0113] Fig.3b illustrates a method of multiplexing A-IoT devices using device specific offsets.

[0114] Fig. 3c illustrates a method of multiplexing A-IoT devices within a common control channel.

[0115] Fig. 4 illustrates introduction of multiplexing A-IoT devices in frequency domain using small frequency shifts by varying pattern for bits.DETAILED DESCRIPTION OF THE INVENTION

[0116] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0117] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).

[0118] The method of operating A-IoT devices comprises the steps mentioned successively. At first step, a reader transmits a trigger signal or an activation signal, which can be broadcasted or transmitted to specific A-IoT device or group of A-IoT devices. The trigger signal (alternatively referred as paging signal) can contain information about the A-IoT device(s) for which the trigger is applicable (e.g., device ID, group ID, device type, etc.); such information is also referred as a paging identity. Additionally or alternatively, the trigger signal can contain information for RACH procedure (E.g., scheduling for MSG1 transmission, number of RACH occasions in time and frequency, carrier frequency for MSG1 transmission, small frequency shift value for MSG1 transmission, type of RACH, content of MSG1, etc.), basic information about network (E.g., ID of reader, frequency of carrier wave, type of use case, and information about common control, repetition related information, etc.). Here the content of MSG1 can indicate to the A-IoT device what to be included in the MSG1, which can include a device ID, a temporary ID, feedback, information stored in memory, measured value, etc. Also, the type of use cases includes inventory, positioning, command, sensing, etc.

[0119] At second step, the A-IoT device(s) receives the trigger signal and initiates the RACH procedure (also known as access procedure). The initiation can be based on identifyingthe correct reader or use case from the trigger signal. For example, the A-IoT device deployed for command use case responds to only trigger signal corresponding to command use case. Further, the A-IoT device can check whether the trigger signal is intended for it or not before initiating the RACH procedure and initiate the procedure only if the trigger signal is intended for it. The RACH procedure can be either contention based (CB) or contention free (CF). In case of CB RACH, the A-IoT devices can determine time / frequency for b ackscattering / transmitting MSG1 randomly from a configured set of time / frequency occasions (e.g., based on slotted aloha). Here, the A-IoT device generates a random number, loads it to a timer, start decrementing the timer and transmit MSG1 at the expiry of the timer. In this case, the range of values for generating the random number, the step size for decrementing the timer, and the window for MSG1 transmission (a. k. a. RACH window) can be either predefined or indicated by the trigger signal. For example, the minimum time gap (shown as R2Dmin in Fig. 1) and maximum time gap (illustrated as R2Dmax in Fig. 1) between a DL operation and a successive UL operation can be predefined and the time duration between them can be defined as the RACH window. In case of CF RACH, the trigger signal indicates the identity of the A-IoT device for which the trigger is applicable and the scheduling for MSG1 transmission. The reader monitors MSG1 on all occasions within the RACH window. Based on the MSG1 signals received within the RACH window, the reader gets information about the number of A-IoT devices trying to access the network, and several information related to those A-IoT devices (E.g., contention, proximity of A-IoT devices, energy status of A-IoT devices, type of A-IoT devices, etc.). Further, the reader can determine the set of MSG1 signals received correctly, identify the A-IoT devices corresponding to successfully received MSG1 signals and identify the A-IoT devices which passed the RACH process based on the information obtained from MSG1.

[0120] At third step, the reader transmits a random access response (RAR) (alternatively referred as random ID response message). The RAR contains information for contention resolution (e.g., indication of A-IoT devices from which MSG1 is received successfully in terms of indicating temp ID / rand number / device ID received in MSG1, frequency resource associated with the successfully received MSG1, etc.), basic information about network or system information (E.g., ID of reader, frequency of carrier wave, repetition related information etc.), multiplexing information for further transmission / reception and scheduling for further transmissions / receptions. The following options can be considered for transmission of the RAR:

[0121] In first option, the reader can transmit RAR as a common control / data signal. An example of such transmission is illustrated in Fig. 1. The following methods can be considered by the A-IoT device for determining the scheduling of common control / data signal.i. In one method, the common control can be transmitted after a predefined time duration (e.g., minimum time gap between an UL operation and subsequent DL operation, i.e., D2Rmin in Fig. 1) from a reference point (e.g., end of RACH window).ii. In another method, a preamble / sequence / pattern precedes common control and is predefined or indicated by the trigger signal to the A-IoT device. The A-IoT device correlates using the preamble / sequence / pattern to find common control. The A-IoT device starts correlating after a predefined time duration (e.g., minimum time gap between an UL operation and subsequent DL operation, i.e., D2Rmin shown in Fig. 1) from a reference point (e.g., end of RACH window).iii. In yet another method, the trigger signal can indicate scheduling information for common control.

[0122] In a second option, the reader can transmit RAR as a device specific control / data signal. For determining the scheduling for device specific control / data signal, a RAR time window, either new or same as RACH window, can be defined for receiving device specific control / data signal. The RAR time window can start immediately after the RACH window or after a predefined time gap (E.g., D2Rmin) from the end of RACH window. The A-IoT device can reinitiate the timer based on the same random number used for transmitting MSG1 and monitor for device specific control at the expiry of the timer. In other words, the A-IoT device expects the time / frequency resource for receiving RAR within the RAR window is same as the time frequency resource used for transmitting MSG1 within the RACH window. In effect the RAR window is divided into multiple RAR occasions similar to ROs within RACH window and the device monitors for device specific control in the RAR occasion, corresponding to the ROs used for transmitting MSG1. An example is illustrated in Fig. 2, where both RACH window and RAR window have 10 occasions and an A-IoT device which has transmitted MSG1 in RO4 within RACH window (indicated in orange) will expect device specific control in RAR occasion 4 within RAR window (indicated in orange).

[0123] In the second option, if an A-IoT device is not receiving device specific control in the RAR occasion, corresponding to the RO used for MSG1 transmission, then the A-IoT device assumes RACH failure and start monitoring for trigger signal. For example, in Fig. 2, an A-IoT device has transmitted MSG1 in RO1 (indicated in green), but no RAR is associated with RAR occasion 1. Therefore, the A-IoT device assumes RACH failure.

[0124] If multiple A-IoT devices have transmitted MSG1 in same RO, then contention occurs, and more than one A-IoT device expects device specific control within the same RAR occasion. However, the reader, after receiving multiple MSG1, determines the MSG1 which passed the process (referred as successful MSG1), and determines the ID associated with the successful MSG1 (either ID contained in successful MSG1 or ID of the A-IoT device which transmitted successful MSG1 or ID associated with frequency resource in which a successful MSG1 is received).

[0125] In one option, the reader can indicate the ID, associated with the successful MSG1, in the A-IoT device specific control and each A-IoT device after receiving the device specific control checks whether the content matches with its ID or the ID transmitted in MSG1 or ID of the frequency resource in which MSG1 was transmitted. If the content matches, then the A-IoT device declares RACH completed successfully. If the content is not matching, then the A-IoT device assumes RACH failure and monitoring for trigger signal again.

[0126] In another option, the reader can scramble the device specific control information using the ID associated with successful MSG1 and each A-IoT device tries to descramble the device specific control using the ID associated with its MSG1 transmission. If descrambling is successful then the A-IoT device assumes that the process is successful, else it will drop the process and start monitoring for trigger again.

[0127] At fourth step, the RAR provides multiplexing information to the A-IoT devices and can be followed by transmi ssion / recepti on of device specific control / data signals in DL and UL. The RAR can be followed by a device specific control / data in DL, which provides command for the A-IoT device, scheduling for UL BSC / transmission, etc. The scheduling for UL can indicate time for UL BSC / transmission, frequency of carrier wave, the value of small frequency shift to be applied on carrier wave while backscattering, amplification factor for backscattering, parameters related to repetition of signal in UL (e.g., number of repetitions,type of repetition, resources for repetition, etc.), parameter to include in UL signal (E.g., A-IoT device ID / energy status / sensor value / information for proximity determination, etc.). The A-loT device specific control / data can be followed by an UL BSC / transmission by the A-IoT device with content device ID, feedback for DL signal / command, energy status, sensed value, value stored in memory, information for proximity determination, etc.

[0128] The method of multiplexing A-IoT devices is described successively. Specifically, multiplexing of device specific control / data signals from readers and also multiplexing of different A-IoT device transmissions is described. The transmission / reception associated with A-IoT devices (e.g. the fourth step explained in previous paragraph) can be multiplexed in time or frequency domains. Specific time durations can be defined for device specific transmissions / receptions so that the A-IoT device can monitor DL / UL within the window, which reduces the monitoring period and saves energy. In one e.g., a minimum time gap between two successive DL operations (R2Rmin) can be defined and the device specific DL window can start after R2Rmin from the start / end of RAR as indicated in Fig. 1. In another e.g., the minimum time gap between successive DL operation and UL operations (R2Dmin) can be defined and the device specific UL window can start after R2Dmin from the start / end of device specific DL window. Similarly, D2Dmin can be defined for successive UL operations and D2Rmin can be defined for successive UL and DL operations.

[0129] One of the several methods described successively can be used for multiplexing A-IoT devices within the device specific transmission / reception window. In a first method, the signals can be preceded by a preamble, which is specific to an A-IoT device. The preamble can be configured by the RAR or can be predefined or can be derived from the A-IoT device ID. The preamble can be a root sequence with a cyclic shift value which is UE specific. The A-IoT device correlates using the preamble within the device specific transmission / reception window and starts DL reception or UL transmission on detecting the preamble. An example is illustrated in Fig.3a, where the device specific window for DL starts after R2Rmin from common control (referred as tO in the figure) and A-IoT devices start correlating using its preamble. A-IoT device 2 (referred to as D2 in the figure) finds a match at time tl and starts receiving control / data signal. A-IoT device 1 finds match at time t2 and starts receiving control / data signal (In the figure, the preamble of the A-IoT device 2 is illustrated in orange and preamble of device 1 is illustrated using green).

[0130] In a second method, the device specific offset with respect to a reference point can be used to determine the start of the device specific signal. The device specific offset can be configured by the RAR or can be predefined or can be derived from the A-IoT device ID. The reference point can be the start of the device specific transmission / reception window or end of the latest DL / UL operation for the A-IoT device. Here, the preamble remains common for all A-IoT devices and can be used for synchronization purposes. An example is illustrated in Fig. 3b, where the A-IoT device 2 apply an offset 2 from the start of the device specific window to determine the start of the DL operation. Similarly, the A-IoT device 1 applies offset 1 to determine the start of the DL operation.

[0131] In a third method, the control / data for multiple A-IoT devices are carried on the same channel, i.e., the channel is group specific. The start of the device specific information within the channel is indicated to the A-IoT device using the device specific offset or the block number. The indication can be in RAR or a common control part within the channel or predefined or derived from device ID. The device specific offset can be applied with respect to the start / end of preamble or start / end of the common control part. An example is illustrated in Fig.3c, where a channel carries data / control for 2 devices: device x and device y. The channel comprises of a preamble, a common control block and device specific blocks. The common control block provides IDs of A-IoT device x and A-IoT device y and offsets for the A-IoT device x and the A-IoT device y. The preamble can be used for indicating the start of the channel and can be used for synchronization. The A-IoT device x monitors the channel using the preamble, obtains its identity and offset on decoding the common control part, apply offset to determine start of the control / data for the A-IoT device x. Another A-IoT device z, monitor for the channel using the preamble, detect the preamble, but fails to obtain its identity from the common control part and identifies that the channel is not intended for it.

[0132] In a fourth method, the channel carrying device specific control / data is processed with device ID related information. The devices blindly monitor the channel, receive the channel and try to decode the channel using its device ID. Only the intended device will be able to decode the channel successfully and extract the content of the channel. The rest of the A-IoT devices fail to decode the channel and continue to do blind monitoring. E.g., the reader embeds the information for device x in a channel and scrambles the channel using the ID / RNTI of the A-IoT device x. If the channel is received by the A-IoT devices x and y, then both A-loT devices try to descramble the channel using their respective IDs. Only the A-IoT device xwill be able to decode the channel and extract the information. In another e.g. the CRC check can be associated with device ID, so that only the intended device passes CRC check, and it fails for rest of the A-IoT devices.

[0133] Once a device specific control / data signal is received, the rest of the transmissions / receptions can be scheduled by the device specific control / data signal, or it can be derived based on reception of device specific control / data signal. For example, when the A-loT device has received a channel containing control / data signal using any of the above methods, then the control / data part of the channel can schedule further operation (E.g., perform command, send feedback, measurement, transmit report, etc.) from the A-IoT device.

[0134] Any of the several methods described successively can be used for multiplexing A-IoT devices using device specific control / data signal. In a first method, the device specific control / data signal can schedule resources for further transmissions / receptions from the A-IoT device. For example, the device specific control / data signal can indicate a time offset with respect to a reference time and length / number of time resources for transmission, to an A-IoT device. The time offset and number of time resources can be in terms of the number of clock cycles. In another e.g., the device specific control / data signal can indicate start and length indicator value (SLIV) from which the A-IoT device can generate the starting resource and length of resources for transmission. In another e.g., the size of DL data / control and UL data / control can be fixed, or maximum size can be fixed, and the end of reception / transmission can be denoted using a postamble.

[0135] In a second method, the offset can be derived from the preamble / device ID / device specific control / data signal. For example, a device specific offset for D2 as shown in Fig. 3b is applied with respect to a reference to determine the resources for transmission by an A-IoT device 2. In another e.g., the position of device specific block in the common control channel (offset for A-IoT device y in Fig.3c) is applied with respect to a reference to determine the time for transmission of device specific signal.

[0136] In a third method, the device transmits in UL after a fixed offset from a reference. For example, the A-IoT device transmits in UL after R2Dmin from the end of reception of device specific control / data signal. The UL can be a scheduling request (e.g.,predefined sequence) which requests the reader to schedule resources for transmission of UL signal.

[0137] The reference time mentioned in the above methods can be an end of device specific control / data signal, after R2Dmin from the end of device specific control / data signal, or preamble / mid amble / post amble associated with the device specific control / data signal. The reader can transmit the preamble to indicate the start of reference time and can be used by the A-IoT device for synchronization. This is helpful especially when the device loses synchronization easily.

[0138] The A-IoT devices can have the capability to shift the frequency of carrier waves along with modulating and backscattering. This capability can be used for multiplexing the UL from A-IoT devices in frequency domain. The device specific control / data signal can indicate a frequency shift value, that needs to be applied by the device while modulating and BSC the carrier wave. The reader can ensure that the frequency shift value is different for different A-IoT devices operating simultaneously. The indication can be absolute value of frequency shift, or an index from the set of frequency shift values supported by A-IoT devices. The set of values can be predefined.

[0139] A small frequency shift can also be achieved varying the frequency of the pattern used to represent l’s and 0’s across the devices. One of the below described methods can be considered for implementing the small frequency shift.

[0140] In a first method, the A-IoT device DI can represent an information bit using R1 square waves within the bit duration whereas other device can represent the information bit using R2 square waves in the bit duration. For example, the information bits {1011} are represented as {10 01 10 10} by DI with R=1 and {1010 0101 1010 1010} by D2 with R=2. Therefore, the A-IoT device D2 repeats the pattern twice and hence the frequency is doubled compared to the A-IoT device DI.

[0141] In a second method, line coding can be repeated multiple times for each information bit. For example, in Manchester line coding scheme, information bit 1 is represented as 10 and 0 is represented as 01. The A-IoT device DI codes the information bits {1011} as {1001 10 10} with repetition R=1 and the A-IoT device D2 codes the informationbit {1011} as {1010 0101 1010 1010} with repetition R=2. Like the previous example, here also the frequency from the A-IoT device D2 is twice as much as that of the A-IoT device DI.

[0142] The scheme is illustrated in Fig. 4. Therefore, the device specific control / data signal can indicate the value of repetition in a time duration or the pattern corresponding to each information bit(s) or number of on-off cycles within a time duration or time duration corresponding to the bit(s) to introduce small frequency shift among the devices. Here, the time duration can be bit duration or block duration and can be indicated in terms of number of clock cycles.

[0143] Reliability is a key aspect in communication systems, especially for low end devices with very low capability, complexity and power consumption. E.g., because of the lower complexity and power constraints, the device cannot perform complex operations like FEC, channel measurement and reporting, complex modulation / demodulation, dynamic adaptations, etc. Repetition of the signal and performing joint detection is a simple and efficient method to improve reliability in such cases. The following methods can be used for configuring repetition to the A-IoT devices.

[0144] In a first method, the reader can configure a type of repetition and a start time to the A-IoT device. The parameters of repetition associated with each type can be predefined. The device determines parameters based on type of repetition configured and transmit / receive accordingly. In a second method, the reader configures parameters of repetition for the A-IoT device.

[0145] The parameters of repetition include the time and frequency pattern in which the repetition is performed, the scheduling for each repetition occasion, the number of repetitions, periodicity, etc. The possible set of values for the number of repetitions can be predefined and the reader can indicate the index from the predefined set as one of the parameters. Readers can transmit a stop message / post amble to terminate the repetition process. The time gap between repetition can be fixed. For example, an A-IoT device may transmit same signal after time duration of D2Dmin, which is the minimum time gap between successive UL transmissions. The scheduling can be the same and different repetition occasions. The signal can include a field (e.g., 1 bit) to indicate whether it is repetition of a previous packet or a new packet.

[0146] It is essential to monitor the operation of the A-IoT device, especially the energy status, for improving efficiency. For example, A-IoT devices with low energy levels can be dropped at the RACH stage itself to avoid device unavailability in between the processes or can be scheduled later in order to provide enough time for energy harvesting. Therefore, feedback from the A-IoT device to the reader is essential. The reader can demand the A-IoT device to transmit feedback using a DL signal. For example, the DL signal can have a 1-bit field to indicate whether feedback needs to be transmitted in the corresponding UL signal or not. Also, the reader can indicate the type of feedback, whether energy status of device or feedback for command performed or ACK / NACK for the control / data signal received.

Claims

WE CLAIM:

1. A method of operating Ambient-Internet-of-Things (A-IoT) devices in a network, the method comprising:monitoring, by a first node, for a paging signal;determining, by the first node, initiation of access procedure;transmitting, by the first node, a first signal comprising at least one ofa randomly generated identity,a feedback related to the paging signal,at least one value, anda message type;monitoring, by the first node, for a random ID response message;receiving, by the first node, the random ID response message; andinitiating, by the first node, transmission of a second signal whenthe randomly generated identity is present in the random ID response message, ora frequency index associated with the random ID response message matches with a value of the frequency resource used for transmission of the first signal.

2. The method as claimed in claim 1, wherein monitoring comprises receiving the paging signal.

3. The method as claimed in claim 1, wherein determining is based on a paging identity present in the paging signal.

4. The method as claimed in claim 3, wherein the paging identity comprises at least one of an identity of the first node,a type of the first node, andan indication to one of the first node or a group of nodes comprising the first node or a null.

5. The method as claimed in claim 1, wherein the paging signal comprises at least one of a paging identity,information about a type of the access procedure,scheduling information, andan identity of a second node transmitting the paging signal.

6. The method as claimed in claim 5, wherein the type of the access procedure is at least one ofcontention based access procedure or contention free access procedure,inventory procedure,command procedure,sensing procedure, andpositioning procedure.

7. The method as claimed in claim 5, wherein the paging identity comprises an identity of the first node when the type of the procedure is one ofcontention free procedure, andcommand procedure.

8. The method as claimed in claim 5, wherein the scheduling information is for at least one of:transmission of the first signal;reception of system information; andreception of the random ID response message.

9. The method as claimed in claim 8, wherein the scheduling information for transmission of the first signal comprises at least one ofnumber of access occasions,number of time resources in an access occasion,number of small frequency shift,information for selecting resources,number of repetitions,information about content of the first signal,a carrier frequency, andat least one value of small frequency shift.

10. The method as claimed in claim 9, wherein the information about the content of the first signal comprises at least one ofthe randomly generated identity of the first node,feedback for the paging signal, andat least one value measured by the first node.

11. The method as claimed in claim 9, wherein the information for selecting resources comprises at least one ofa start time of a timer,a step size for decrementing the timer,a time window for transmission of the first signal, andone of number of bits M and range of values for generating a random number to select the resource.

12. The method as claimed in claim 5, wherein the scheduling information comprises at least one ofa pattern,a sequence, anda time window for monitoring for at least one of a system information and the random ID response message.

13. The method as claimed in claim 1, wherein monitoring comprises at least one of:correlating using one of a pattern and a sequence;identifying one of the pattern and the sequence; andreceiving a type of signal.

14. The method as claimed in claim 13, wherein one of the pattern and the sequence is predefined, orindicated in the paging signal.

15. The method as claimed in claim 13, wherein identifying one of the pattern and the sequence indicatestart of the reception, orend of the reception.

16. The method as claimed in claim 13, wherein the type of signal comprises one of the paging signal,a trigger signal,the random ID response message,a feedback signal,a control signal, anda data signal.

17. The method as claimed in claim 1, wherein monitoring is donewithin a time window, orafter a minimum time duration from one oftransmitting the first signal, andend of a time window configured for transmitting the first signal.

18. The method as claimed in claim 17, wherein the time window is one ofa time difference between first and last resource configured for transmission of first signal, anda time difference between the minimum time duration and a maximum time duration, which are predefined.

19. The method as claimed in claim 18, wherein the maximum time duration is between a transmission and subsequent reception.

20. The method as claimed in claim 17, wherein the minimum time duration is predefined, andbetween a transmission and subsequent reception.

21. The method as claimed in claim 1, wherein the randomly generated identity is generated using a random number represented using N bits.

22. The method as claimed in claim 5, wherein the value of N is one of 8, 16 and 32.

23. The method as claimed in claim 1, wherein transmitting comprises at least one ofmonitoring for a preamble,correlating using the preamble,transmitting the preamble indicating start of transmission, andtransmitting a postamble indicating end of transmission.

24. The method as claimed in claim 1, wherein the at least one value isstored in the memory of the first node, ormeasured by the first node.

25. The method as claimed in claim 1, wherein the frequency index associated with the random ID response message is one ofa frequency index indicated by the random ID response message, anda frequency resource of receiving the random ID response message.

26. The method as claimed in claim 1, wherein the random ID response message comprises at least one ofa common control information, anda device specific control information.

27. The method as claimed in claim 26, wherein the location of the device specific control information is obtained using the common control information.

28. The method as claimed in claim 27, wherein the device specific control information is obtained by one ofcorrelating using a sequence specific to the first node,descrambling of the possible device specific control information using the identity of the first node, andperforming CRC on the possible device specific control information using the identity of the first node.

29. The method as claimed in claim 28, wherein the sequence is configured by the common control information or is predefined.

30. The method as claimed in claim 1, wherein the random ID response message comprises at least one ofat least one identity,at least one frequency index,network information,multiplexing information, andscheduling information.

31. The method as claimed in claim 30, wherein scheduling information comprises at least one ofscheduling for device specific control information,time resource for transmission of the second signal,carrier frequency for transmission of the second signal,value of small frequency shift for transmission of the second signal,value of amplification factor for the second signal,parameters related to repetition of the second signal, andinformation about content of the second signal.

32. The method as claimed in claim 31, wherein the parameters related to repetition comprises at least one ofnumber of repetition,type of repetition,resources for repetition,pattern of repetition, andnumber of square waves within a bit duration.

33. The method as claimed in claim 31, wherein the information about the content of the second signal comprises at least one ofan identity of the first node,an energy status of the first node,a feedback for the random ID response message, andat least one value measured by the at least one first node.

34. The method as claimed in claim 31, wherein the scheduling for device specific control information comprises at least one ofan identity of the first node,start of device specific control information for the first node in the random ID response message,length of the device specific control information for the first node, andan index of the block corresponding to the device specific control information in the random ID response message.

35. The method as claimed in claim 30, wherein the multiplexing information comprises at least one ofa preamble for the first node for one of transmission and monitoring,a value of cyclic shift to apply to the preamble,at least one time resource for the first node for one of transmission and monitoring, and a time offset for the first node for one of transmission and monitoring.

36. The method as claimed in claim 35, wherein the preamble comprises at least one of a pattern, anda sequence.

37. The method as claimed in claim 1, wherein transmitting is performed after one of detecting a preamble, anda time duration from a reference time instant.

38. The method as claimed in claim 37, wherein the time duration is one of predefined,configured in the random ID response message, andderived, by the first node, based on an identity of the first node.

39. The method as claimed in claim 37, wherein the reference time instant is one of:end of time window for reception of random ID response message,start of the time window for transmission of the second signal, andtime instant of receiving one of the random ID response message and the preamble.

40. The method as claimed in claim 1, wherein transmitting the first signal comprises randomly selecting an access occasion for transmission of the first signal from a set of access occasions, configured by the paging signal.

41. The method as claimed in claim 40, wherein randomly selecting the access occasion comprises:generating a random number within a range; andselecting the access occasion corresponding to the random number.

42. The method as claimed in claim 41, wherein the range is between zero and number of access occasions configured by the paging signal.

43. The method as claimed in claim 41, wherein selecting is according to count down behavior,wherein the countdown behaviour starts from receiving the paging message and continue untiltransmitting the first signal, orreceiving a different paging signal.

44. The method as claimed in claim 43, wherein the count down behaviour comprises setting the random number to a counter, andperforming one ofselecting an occasion next to the random number, when the value of the counter is less than a first value, anddecrementing the counter by the first value, when the value of the counter is more than or equal to the first value, and selecting the occasion next to the random number, when the value of the counter is less than the first value.

45. The method as claimed in claim 44, wherein decrementing is performed on receiving a trigger signal, until the value of the counter is less than the first value.

46. The method as claimed in claim 44, wherein selecting the occasion next to the random number is from the first value of resources triggered by one of the paging signal and a trigger signal.

47. The method as claimed in claim 44, wherein the first value is the product ofa number of small frequency shift for transmission of the first signal, anda number of time resources in an access occasion for transmission of the first signal.

48. The method as claimed in claim 49, wherein the first value is the product ofa number of small frequency shift for transmission of the first signal, anda number of time resources in an access occasion for transmission of the first signal.

49. The method as claimed in claim 1, wherein the second signal comprises at least one ofan identity of the first node,a feedback for the random ID response message,energy status of the first node,scheduling request to allocate resources for transmission,at least one value measured by the first node,at least one value stored in the memory of the first node, andthe message type.

50. The method as claimed in claim 1 and 51, wherein the message type is one ofa random ID message,a data message, anda control message.

51. The method as claimed in claim 1 , wherein the first node determines process failure when no random ID response message is received.

52. The method as claimed in claim 1, wherein transmitting comprisesperforming small frequency shift by representing an information bit using P square-wave cycles per bit duration.

53. The method as claimed in claim 54, wherein the value of P is randomly selected by the first node from a plurality of values.

54. The method as claimed in claim 55, wherein the plurality of values arepredefined, orconfigured in one of the paging signal and the random ID response message.

55. The method as claimed in claim 9, wherein the at least one value of small frequency-shift is one ofan absolute value of small frequency shift,an index corresponding to a predefined set of small frequency-shift values, and number of square-wave cycles per bit duration.

56. A method of operating Ambient-Intemet-of-Things (A-IoT) devices in a network, comprising:transmitting, by a second node, a paging signal,receiving, by the second node, at least one first signal comprising at least one ofat least one first identity,feedback related to the paging signal,at least one value, anda message type;transmitting, by the second node, at least one random ID response message comprising indication of successful completion of access procedure to at least one first node,wherein the indication of successful completion of access procedure comprises at least one second identity from the at least one first identity and at least one frequency index, andreceiving, by the second node, at least one second signal from the at least one first node.

57. The method as claimed in claim 56, wherein the at least one second identity is successfully received by the second node in the at least one first signal.

58. The method as claimed in claim 56, wherein receiving the at least one first signal comprises at least one of:determining the at least one second identity;determining at least one third signal comprising the at least one second identity; determining at least one small frequency shift associated with the at least one third signal; anddetermining the at least one frequency index corresponding to the small frequency shift.

59. The method as claimed in claim 56, wherein the paging signal comprises at least one ofpaging identity,information about type of the access procedure,scheduling information, andidentity of the second node.

60. The method as claimed in claim 59, wherein the paging identity select at least one third node to initiate access procedure.

61. The method as claimed in claim 59, wherein the paging identity comprises identity of the at least one third node when the type of the access procedure is one ofcontention free procedure, andcommand procedure.

62. The method as claimed in claim 59, wherein the type of the access procedure comprises at least one ofone of contention based access procedure and contention free access procedure, inventory procedure,command procedure,sensing procedure, andpositioning procedure.

63. The method as claimed in claim 59, wherein the scheduling information is for at least one third node to at least one oftransmit the at least one first signal,receive system information, andreceive the at least one random ID response message.

64. The method as claimed in claim 59, wherein the scheduling information comprises at least one ofnumber of access occasions,number of time resources in an access occasion,number of small frequency shift,information for selecting resources,number of repetitions,indication of content of the at least one first signal,a carrier frequency,at least one value of small frequency shift,a pattern,a sequence, anda time window for at least one third node to monitor for at least one of a system information and the random ID response message.

65. The method as claimed in claim 64, wherein the indication of the content of the at least one first signal comprises at least one ofa randomly generated identity of the at least one third node,an identity of the at least one third node,a feedback for the paging signal, andat least one value measured by the at least one third node.

66. The method as claimed in claim 64, wherein information for selecting resources comprises at least one ofa start time of a timer,a step size for decrementing the timer,time window for the transmission of the at least one first signal, andone of number of bits M and range of values for generating a random number to select the resource.

67. The method as claimed in claim 59, wherein the paging identity comprises at least one ofan identity of at least one third node,a type of the at least one third node, andan indication to at least one third node or a null.

68. The method as claimed in claim 56, wherein the at least one first signal is received from at least one third node selected in the paging signal.

69. The method as claimed in claim 56, wherein receiving comprises at least one of monitoring using one of pattern and a sequence;identifying one of the pattern and the sequence; andreceiving the type of signal.

70. The method as claimed in claim 69, wherein the pattern and the sequence is predefined, orconfigured, by the second node, using one of paging signal and the random ID response message.

71. The method as claimed in claim 69, wherein identifying one of the pattern and the sequence indicate one ofstart of the reception, andend of the reception.

72. The method as claimed in claim 69, wherein the type of signal comprises one of the at least one first signal,the at least one second signal,a data signal, anda control signal.

73. The method as claimed in claim 69, wherein monitoring is at least one ofwithin a time window, andafter a minimum time duration from one ofend of a time window configured for transmitting the random ID response message, andtransmitting one of the paging signal and the random ID response message.

74. The method as claimed in claim 73, wherein the minimum time duration ispredefined, andbetween a transmission and subsequent reception.

75. The method as claimed in claim 56, wherein transmitting comprises at least one of transmitting one of a first pattern and a first sequence indicating start of one of paging signal and random ID response message,transmitting one of a second pattern and a second sequence indicating end of one of paging signal and random ID response message,transmitting one of a third pattern or a third sequence to indicate start of one of first signal and second signal,transmitting type of signal, andtransmitting a trigger signal indicating start of an access occasion configured by the paging signal.

76. The method as claimed in claim 75, wherein one of the first pattern, the first sequence, the second pattern, the second sequence, the third pattern and the third sequence is one of predefined, andconfigured, by the second node, using one of paging signal and the random ID response message.

77. The method as claimed in claim 75, wherein the type of signal comprisesthe paging signal,a trigger signal,the random ID response message,a feedback signal,a control signal, anda data signal.

78. The method as claimed in claim 56, wherein transmitting the at least one random ID response message is in a frequency resource, where at least one third signal is received.

79. The method as claimed in claim 78, wherein the at least one random ID response message contains the at least one second identity received in the at least one third signal.

80. The method as claimed in claim 58 and 78, wherein the at least one third signal is a subset of at least one first signal, which is successfully received by the at least one second node.

81. The method as claimed in claim 56, wherein the at least one frequency index indicates the small frequency shift associated with one or more of the at least one first signal comprising the at least one second identity.

82. The method as claimed in claim 56, wherein the at least one first identity is randomly generated using a random number represented using N bits.

83. The method as claimed in claim 82, wherein the value of N is one of 8, 16 and 32.

84. The method as claimed in claim 56, wherein the random ID response message further comprises at least one ofa common control information,at least one device specific control information,network information,multiplexing information, andscheduling information.

85. The method as claimed in claim 84, wherein the at least one device specific control information is at least one ofapplicable for one or more of the at least one first node, andscrambled using identity of one or more of the at least one first node.

86. The method as claimed in claim 84, wherein scheduling information comprises at least one ofscheduling for the at least one device specific control information,time resource for transmission of the second signal,carrier frequency for transmission of the second signal,value of small frequency shift for transmission of the second signal,value of amplification factor for the second signal,parameters related to repetition of the second signal, andinformation about content of the second signal.

87. The method as claimed in claim 86, wherein the parameters related to repetition comprises at least one ofnumber of repetition,type of repetition,resources for repetition,pattern of repetition, andnumber of square waves within a bit duration.

88. The method as claimed in claim 86, wherein the information about the content of the at least one second signal comprises at least one ofidentity of the at least one first node,energy status of the at least one first node,feedback for the random ID response message, andat least one value measured by the at least one first node.

89. The method as claimed in claim 86, wherein the scheduling for the at least one device specific control information comprises at least one ofidentity of one or more of the at least one first node,preamble associated with the at least one device specific control information, start of the at least one device specific control information,length of the at least one device specific control information, andindex of the block corresponding to the at least one device specific control information.

90. The method as claimed in claim 84, wherein the multiplexing information comprises at least one ofa preamble for the at least one first node for one of transmission and monitoring, a value of cyclic shift to apply to the preamble,at least one time resource for the at least one first node for one of transmission and monitoring, anda time offset for the at least one first node for one of transmission and monitoring.

91. The method as claimed in claim 90, wherein the preamble comprises at least one of a pattern, anda sequence.

92. The method as claimed in claim 75, wherein the trigger activates a first value of resources for transmission of the at least one first signal.

93. The method as claimed in claim 92, wherein the first value is the product ofa number of small frequency shift for transmission of the at least one first signal, and a number of time resources in an access occasion for transmission of the at least one first signal.

94. The method as claimed in claim 56, wherein the second signal comprises at least one of an identity of the at least one first node,a feedback for the at least one random ID response message,energy status of the at least one first node,scheduling request,at least one value measured by the at least one first node,at least one value stored in the memory of the at least one first node, andthe message type.

95. The method as claimed in claim 56 and 94, wherein the message type is one ofa random ID message,a data message, anda control message.

Images