Multimode input matching network for low power receivers

Abstract

A method, input matching network and wireless receiver are disclosed. According to one aspect, an input matching network of a wireless receiver includes a resonance circuit configured to resonate at a resonant frequency and a tunable negative transconductance circuit in communication with the resonance circuit and configured to alter a Q-factor of the resonance circuit. The tunable negative transconductance circuit is configured to operate the wireless receiver in a linear mode when a power of a signal received by the wireless receiver is within a first range, to operate the wireless receiver in a super-regenerative oscillating (SRO) mode when an output of the input matching network begins to oscillate.

Description

[0001] MULTIMODE INPUT MATCHING NETWORK FOR LOW POWER RECEIVERS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications, and in particular, to multimode input matching networks for low power receivers.

[0004] BACKGROUND

[0005] The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs. The 3GPP is also developing standards for Sixth Generation (6G) wireless communication networks.

[0006] In a wireless communication system, signal transmission and reception are very important. Performance parameters to be considered in an RF receiver include sensitivity, selectivity, supported data rate, and power consumption. As most wireless devices are powered by battery, it is important to reduce power consumption in RF receivers so that the device battery time is prolonged.

[0007] There are a wide variety of existing low-power RF receivers. The RF receiver architectures may be broadly divided into three categories namely homodyne, heterodyne, and RF detection. A frequency synthesizer is required in the homodyne and heterodyne receivers which have a proven improvement in the receiver sensitivity at the cost of power consumption. On the other hand, RF detection receivers are non-coherent, do not require any frequency synthesizer and thus consume lower power compared to the coherent detection (homodyne, heterodyne) receivers.

[0008] There is another class of receivers called the super-regenerative receivers in which the receiver front-end oscillates depending on the signal presence at the input and thus, the RF signal gets amplified in a non-coherent and non-linear manner. An advantage of such receivers is that the oscillations are excited only when the input signal amplitude is modulated to be “ON” and that may be detected by a simple envelope detector, lowering power consumption. If the envelope detection is performed at RF, there is no need for any frequency synthesizer, further lowering the power consumption of the RF receiver. The existing / published low-power RF receivers critically suffer from a major trade-off between the sensitivity, data rate, and power consumption. For example, the non-coherent detection receivers achieve a decent sensitivity at a very low power consumption for very low data rates or achieve a poor sensitivity at a very low power consumption for decent data rates. The coherent detection receivers consume more power to provide a stable frequency synthesizer for RF signal down-conversion. These receivers often achieve very good sensitivity for higher data rate signals.

[0009] The super-regenerative receivers consume more power compared to the non-super- regenerative non-coherent detection receivers, but achieve better sensitivity. This provides possibilities for improved sensitivity for higher data rate signals, still at very low power consumption compared to coherent detection receivers.

[0010] SUMMARY

[0011] Some embodiments advantageously provide methods, input matching networks and low power receivers.

[0012] Some embodiments may enable a low power receiver in a wireless device (WD) to adapt its power consumption according to the input signal strength. In other words, when the received signal strength is small, the receiver may consume more power to detect / decode the small signal. When the received signal strength is large, then the receiver may detect and decode the signal while consuming less power.

[0013] Some embodiments provide a multimode input matching network (IMN) and the associated control loop for low power receivers, enabling a controllable RF signal gain at the input of the receiver with respect to the signal strength at the input of the receiver. In some embodiments, the wireless receiver has two operating modes:

[0014] 1. A linear mode, in which the linear RF signal gain of the IMN may be controlled within a certain range depending on whether the signal strength at the input of the receiver is large enough to provide a minimum required value of signal to noise ratio (SNR) at the baseband output. The gain may be controlled by enhancing the Q-factor of the IMN, e.g., using crosscoupled negative-gm circuit; and

[0015] 2. A “super regenerative oscillator (SRO)” mode, which is activated when the baseband output SNR falls below a certain threshold in the linear mode. In the SRO mode, the IMN may be triggered to oscillate in a periodic manner using a quench signal provided by circuitry in communication with an IF demodulator. The average power consumption of the low power receiver may be greatly reduced for better sensitivity performance accounting to longevity of the power source of the WD. In some embodiments, the low power receiver adjusts the transconductance of the IMN depending on the received signal strength. A larger transconductance may be provided when the received signal strength is low. Over time, on average, the power consumed by the receiver may be smaller compared to existing receivers that achieve the same order of sensitivity.

[0016] In some embodiments, the receiver operates in one of two different modes depending on the received signal strength. If the signal strength is very low, the receiver operates in super- regenerative mode. Otherwise the receiver operates in linear mode.

[0017] Some embodiments are largely independent of the operating frequency, and may be adapted to other frequency bands than the ones disclosed herein. In some embodiments, the center-frequency of the IMN depends on the values of an inductor and a capacitor in the LC tank. Thus, the frequency may be scaled to higher orders by lowering the L and C values. In some embodiments, the center-frequency of the IMN may be tuned by using a varactor or programmable capacitor in place of a fixed capacitor, adding channel-selection features to the receiver.

[0018] According to one aspect, a wireless receiver configurable to operate in a linear mode or in a super-regenerative oscillating, SRO, mode is provided. The wireless receiver includes an input matching network comprising: a resonance circuit configured to resonate at a resonant frequency; and a tunable negative transconductance circuit in communication with the resonance circuit and configured to alter a Q-factor of the resonance circuit. The wireless receiver includes control circuitry in communication with the input matching network and configured to generate a bias voltage to the tunable negative transconductance to control when the wireless receiver operates in the linear mode and when the wireless receiver operates in the SRO mode.

[0019] According to this aspect, in some embodiments, the wireless receiver is configured to operate in a linear mode when a power of a signal received by the wireless receiver is within a first range and to switch to operating in the SRO mode when an output of the input matching network oscillates. In some embodiments, the wireless receiver is configured to operate in the linear mode until oscillations are detected in an output of the input matching network and is configured to operate in the SRO mode until the received signal power exceeds a first threshold. In some embodiments, the control circuitry is configured to switch to the SRO mode when oscillations are detected in an output of the input matching network. In some embodiments, the wireless receiver is configured to switch to the linear mode when the received signal power exceeds a first threshold. In some embodiments, the control circuitry includes switching circuitry configured to select between first circuitry configured to generate a first bias voltage to configure the tunable negative transconductance circuit to operate the wireless receiver in the linear mode and second circuitry configured to generate a second bias voltage to configure the tunable negative transconductance circuit to operate the wireless receiver (24) in the SRO mode. In some embodiments, the control circuitry includes an amplifier configured to amplify the difference between a filtered envelope signal and a target envelope value and includes a quench waveform generator, QWG, configured to generate a waveform that alternates between two states until a threshold received signal power is reached. In some embodiments, when operating in the linear mode, the input matching network is configured to control a gain of the wireless receiver to provide a minimum signal strength at a baseband output. In some embodiments, the SRO mode is activated when a signal strength at a baseband output falls below a second threshold when operating in the linear mode. In some embodiments, the input matching network further comprises a variable or programmable capacitor configured to tune a resonant frequency of the resonance circuit.

[0020] According to yet another aspect, a method in a wireless receiver a wireless device, WD, is provided. The method includes, while operating the wireless receiver in a linear mode: continuing to operate the wireless receiver in the linear mode as long as a preamble of a signal received by the wireless receiver matches a predetermined preamble; and when the preamble no longer matches the predetermined preamble, switching to operating the wireless receiver in a super-regenerative oscillating, SRO, mode. The method includes, while operating the wireless receiver in the SRO mode: continuing to operate the wireless receiver in the SRO mode until a power of the received signal exceeds a first threshold; and when the received signal power exceeds the first threshold, switching to operating the wireless receiver in the linear mode.

[0021] According to this aspect, in some embodiments, the method includes switching from the linear mode to the SRO mode when oscillations are detected in an output of an input matching network. In some embodiments, the method includes, when operating in the linear mode, configuring the input matching network to control a gain of the wireless receiver to provide a minimum signal strength at a baseband output of the wireless receiver. In some embodiments, the method includes, when operating in the linear mode, switching to operating the wireless receiver in the SRO mode when a signal strength of a baseband output of the wireless receiver falls below a second threshold. In some embodiments, the method includes, when operating in the SRO mode providing a bias voltage to the input matching network that alternates between two states. According to another aspect, a wireless receiver is configure to: while operating in a linear mode: continuing to operate in the linear mode as long as a preamble of a signal received by the wireless receiver matches a predetermined preamble; and when the preamble no longer matches the predetermined preamble, switching to operating in a super-regenerative oscillating, SRO, mode. While operating in the SRO mode, the wireless receiver is configured to continue to operate in the SRO mode until a power of the received signal exceeds a first threshold; and when the received signal power exceeds the first threshold, switch to operating in the linear mode.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

[0024] FIG. l is a schematic diagram of an example network architecture illustrating a communication system according to principles disclosed herein;

[0025] FIG. 2 is a block diagram of a network node in communication with a wireless device over a wireless connection according to some embodiments of the present disclosure;

[0026] FIG. 3 is a flowchart of an example process in a wireless receiver of a wireless device according to some embodiments of the present disclosure;

[0027] FIG. 4 is a block diagram of an example embodiment of a low-power receiver with an input matching network and associated control circuitry;

[0028] FIG. 5 is an example of an input matching network constructed according to principles disclosed herein;

[0029] FIG. 6 are graphs of gain and consumed power versus an analog bias voltage;

[0030] FIG. 7 illustrates receiver sensitivity and power consumption in different operating modes;

[0031] FIG. 8 is a block diagram of control circuitry for controlling a receiver mode via an IMN;

[0032] FIG. 9 is a flowchart of an example process for selecting between receiver modes of operation;

[0033] FIG. 10 illustrates transitions in Vbias with respect to changes in input signal strength; and FIG. 11 illustrates gain versus center frequency of a variable capacitance resonance circuit of an input matching network (IMN).

[0034] DETAILED DESCRIPTION Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to multimode input matching networks for low power receivers. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0035] As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0036] In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

[0037] In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and / or wireless connections.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and / or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0039] The term “network node” used herein may be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell / multicast coordination entity (MCE), relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

[0040] In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein may be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and / or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device etc.

[0041] Also, in some embodiments the generic term “radio network node” is used. It may be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell / multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

[0042] Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and / or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

[0043] Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, may be distributed among several physical devices.

[0044] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0045] Some embodiments are directed to multimode input matching networks for low power receivers.

[0046] Referring to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 1 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP -type cellular network that may support standards such as LTE and / or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

[0047] Also, it is contemplated that a WD 22 may be in simultaneous communication and / or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 may have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 may be in communication with an eNB for LTEZE-UTRAN and a gNB for NR / NG-RAN.

[0048] A wireless device 22 is configured to include a wireless receiver 24 which is configured to include an input matching network 26 configured according to principles disclosed herein. A wireless device 22 may be a user equipment or any other wireless device including a smart watch, a virtual reality glass, an Internet of things (loT) device, a dongle, etc. A first wireless device 22a may be in sidelink communication with a second wireless device 22b. For example, wireless device 22a may be a smart phone and wireless device 22b may be a smart watch that is configurable to interoperate with the wireless device 22a.

[0049] Example implementations, in accordance with an embodiment, of the WD 22 and network node 16 discussed in the preceding paragraphs will now be described with reference to FIG. 2.

[0050] The communication system 10 includes a network node 16 provided in a communication system 10 and including hardware 28 enabling it to communicate with the WD 22. The hardware 28 may include a radio interface 30 for setting up and maintaining at least a wireless connection 32 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 30 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 30 includes an array of antennas 34 to radiate and receive signal(s) carrying electromagnetic waves.

[0051] In the embodiment shown, the hardware 28 of the network node 16 further includes processing circuitry 36. The processing circuitry 36 may include a processor 38 and a memory 40. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 36 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 38 may be configured to access (e.g., write to and / or read from) the memory 40, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0052] Thus, the network node 16 further has software 42 stored internally in, for example, memory 40, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 42 may be executable by the processing circuitry 36. The processing circuitry 36 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by network node 16. Processor 38 corresponds to one or more processors 38 for performing network node 16 functions described herein. The memory 40 is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 42 may include instructions that, when executed by the processor 38 and / or processing circuitry 36, causes the processor 38 and / or processing circuitry 36 to perform the processes described herein with respect to network node 16.

[0053] The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 44 that may include a radio interface 46 configured to set up and maintain a wireless connection 32 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 46 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and / or one or more RF transceivers. The radio interface 46 includes an array of antennas 48 to radiate and receive signal(s) carrying electromagnetic waves. The radio interface of the wireless device 22 may include a wireless receiver 24 which is configured to include an input matching network 26 configured according to principles disclosed herein. The wireless receiver 24 may also be configured to include control circuitry 60 configured according to principles disclosed herein.

[0054] The hardware 44 of the WD 22 further includes processing circuitry 50. The processing circuitry 50 may include a processor 52 and memory 54. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 50 may comprise integrated circuitry for processing and / or control, e.g., one or more processors and / or processor cores and / or FPGAs (Field Programmable Gate Array) and / or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 52 may be configured to access (e.g., write to and / or read from) memory 54, which may comprise any kind of volatile and / or nonvolatile memory, e.g., cache and / or buffer memory and / or RAM (Random Access Memory) and / or ROM (Read-Only Memory) and / or optical memory and / or EPROM (Erasable Programmable Read-Only Memory).

[0055] Thus, the WD 22 may further comprise software 56, which is stored in, for example, memory 54 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 56 may be executable by the processing circuitry 50. The software 56 may include a client application 58. The client application 58 may be operable to provide a service to a human or non-human user via the WD 22. The processing circuitry 50 may be configured to control any of the methods and / or processes described herein and / or to cause such methods, and / or processes to be performed, e.g., by WD 22. The processor 52 corresponds to one or more processors 52 for performing WD 22 functions described herein. The WD 22 includes memory 54 that is configured to store data, programmatic software code and / or other information described herein. In some embodiments, the software 56 and / or the client application 58 may include instructions that, when executed by the processor 52 and / or processing circuitry 50, causes the processor 52 and / or processing circuitry 50 to perform the processes described herein with respect to WD 22.

[0056] In some embodiments, the inner workings of the network node 16 and WD 22 may be as shown in FIG. 2 and independently, the surrounding network topology may be that of FIG. 1.

[0057] The wireless connection 32 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and / or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc. In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve.

[0058] FIG. 3 is a flowchart of an example process in a wireless device 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device 22 such as by one or more of processing circuitry 50, processor 52, and / or radio interface 46 (including the input matching network 26). Wireless device 22 such as via processing circuitry 50 and / or processor 52 and / or radio interface 46 is configured to, while operating the wireless receiver 24 in a linear mode (Block S10): continuing to operate the wireless receiver in the linear mode as long as a preamble of a signal received by the wireless receiver 24 matches a predetermined preamble (Block S12); and when the preamble no longer matches the predetermined preamble, switching to operating the wireless receiver 24 of the wireless receiver 24 in a super-regenerative oscillating, SRO, mode (Block S14). The method includes, while operating the input matching network in the SRO mode (Block SI 6): continuing to operate the wireless receiver 24 in the SRO mode until a power of the received signal exceeds a first threshold (Block SI 8); and when the received signal power exceeds the first threshold, switching to operating the wireless receiver 24 in the linear mode (Block S20).

[0059] In some embodiments, the method includes switching from the linear mode to the SRO mode when oscillations are detected in an output of the input matching network 26. In some embodiments, the method includes, when operating in the linear mode, configuring the input matching network 26 to control a gain of the wireless receiver 24 to provide a minimum signal strength at a baseband output of the wireless receiver 24. In some embodiments, the method includes, when operating in the linear mode, switching to operating the wireless receiver 24 in the SRO mode when a signal strength of a baseband output of the wireless receiver 24 falls below a second threshold. In some embodiments, the method includes, when operating in the SRO mode providing a bias voltage to the input matching 26 network that alternates between two states.. Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for multimode input matching networks for low power receivers.

[0060] Example Embodiment: low power receiver featuring tunable IMN and associated control block.

[0061] FIG. 4 is a block diagram of an example embodiment of a low-power receiver 24 with an input matching network 26 and associated control circuitry 60. The wireless receiver 24 may include a mixer 64, a low pass filter 66, an IF amplifier 68 and a baseband stage 70. The principles disclosed herein are applicable to other wireless receiver architectures.

[0062] The control circuitry 60 may have the following two features:

[0063] 1. It detects the down-converted signal amplitude to decide on the mode of operation of the wireless receiver 24; and / or

[0064] 2. It controls the parameters of the IMN 26 to change its gain and effectively select the desired mode of operation.

[0065] In some embodiments, the control circuitry 60 selects between two operating modes:

[0066] - A “linear” mode, in which the linear gain of the IMN 26 may be controlled within a certain range depending on the signal strength at the input of the wireless receiver 24 being large enough to provide a minimum value of signal to noise ratio (SNR) at the baseband output. The gain may be controlled by enhancing the Q-factor of the IMN 26 using a cross-coupled negative-gm circuit, for example; and

[0067] - A “super regenerative oscillator (SRO)” mode, which is activated when the baseband output SNR falls below a certain value in the “linear” mode. In the SRO mode, the IMN 26 is caused to oscillate in a periodic manner using a quench signal generated within the control circuitry 60.

[0068] Some embodiments provide a tunable IMN implementation in a wireless receiver architecture together with the down-converted signal amplitude detection and control circuitry 60. Tunable matching network implementation.

[0069] A schematic diagram of a circuit of one example implementation for the tunable input matching network is illustrated in FIG. 5. This input matching network 26 includes a resonance circuit 72, which may be a classical fixed LC tank (illustrated in FIG. 5 with a parallel topology but not limited to this topology), and a tunable negative transconductance circuit 74. The capacitor 76 connecting to RFinmay be part of the resonance so that a passive voltage gain may occur.

[0070] The tunable negative transconductance circuit 74, placed in parallel with the resonance circuit 72, increases the Q-factor of the resonance circuit 72. The tunable negative transconductance circuit 74 may be implemented with a classical cross-coupled topology (negative-gm circuit, also known as negative-resistance circuit) which features a tunable analog bias voltage Vbias, which effectively tunes the negative transconductance value of the tunable negative transconductance circuit 74.

[0071] By negative transconductance or negative transconductance circuit, it is intended a negative conductance or negative conductance circuit.

[0072] The Q-factor of the resonance circuit 72 is effectively controlled by setting the analog voltage Vbias. The Q-factor increases when the transconductance increases. However, this is only possible up to a certain point, at which the Q-factor becomes infinite. This point ideally signifies the value at which the magnitude of effective resistance of the negative-gm circuit equals the shunt resistance of the resonance circuit 72, alone. In other words, the effective shunt resistance across the resonance circuit 72 becomes infinite. Beyond this point, the resonance circuit 72 starts oscillating at the resonant frequency which may be designed (or adjusted) to be close to the received signal frequency.

[0073] Simulations have been performed as described in the following paragraphs.

[0074] The simulated small signal (AC) gain obtained from the IMN 26, and the power consumed by the negative-gm circuit, versus analog bias voltage Vbias are shown in FIG. 6. The negative-gm circuit shown in FIG. 5 may be designed using 7nm CMOS process PDK transistors.

[0075] As proof of validation, an LC tank (the resonance circuit 72) was modeled to include an inductor of 13nH with a Q-factor of 7 and a capacitor of 17fF. The total capacitor 76 is 30 fF, which also includes the parasitic capacitances of the transistors in the negative conductance circuit 74, each with size 1.12um / 8nm. The corresponding peak center frequency for the IMN gain is around 5.54GHz. Using this as the input frequency, the gain of the IMN 26 and average power consumption of the negative-gm circuit in the tunable negative transconductance circuit 74 are plotted FIG. 6 As Vbias increases, the negative transconductance increases and the total conductance of the LC tank decreases. Beyond 600mV of Vbias, the total conductance of the LC tank becomes negative, and the circuit becomes unstable, i.e., it would start to oscillate in a transient simulation. (In the AC simulation shown, however, as the poles move into the right half-plane, the gain seemingly drops.) Thus, in the “linear” mode of operation for the wireless receiver 24, bias should not exceed 600mV for stability reasons.

[0076] For smaller Vbias voltages (much less than 400m V), the transconductance of the negative- gmcircuit 74 is negligible as is the power consumption and does not provide any improvement to the gain of the IMN 26.

[0077] The receiver sensitivity in different operating modes is illustrated in FIG. 7. It is evident that the RX sensitivity is better in SRO mode as compared to the linear mode. Correspondingly, the power consumption increases with an increase in the Vbias voltage, as illustrated in FIG. 6. The average power consumption of the negative-gmcircuit in SRO mode is around 31 pW. Down-converted signal amplitude detection and IMN control block implementation

[0078] A schematic diagram of one example embodiment of the control circuitry 60 is shown in FIG. 8. The “RX operation” block 78 shown in FIG. 8 includes an envelope detector 80, a baseband amplifier 82 and a comparator 84. The output of the comparator 84 may be input to a digital baseband unit of the wireless receiver 24. The input of the RX operation block 78 is connected to the output of IF amplifier 68 of the circuit shown in FIG. 4. The Rx operation block 78 provides RX operation based on amplitude modulation while providing inputs for the control circuitry 60. The RX operation block 78 may also contain analog filters (not shown) that are tailored to the envelope modulation frequencies present in the signal to receive, for enhanced sensitivity.

[0079] The control circuitry 60 performs the function of selecting between the different modes of operation for the IMN 26. In addition, the control circuitry 60 also tunes the IMN gain in the “linear” mode. The control circuitry 60 includes a low pass filter (LPF 86) (for which the input corresponds to the output of the envelope detector from the RX block), an amplifier 88, a multiplexer 90 setting the Vbias value, a quench waveform generator (QWG) 92 and a processor 94.

[0080] A role of the processor 94 is to decide the mode of operation of the wireless receiver 24. The switching between the two modes of the wireless receiver 24 may be directed by using the multiplexer 90. The processor 94 may be configured to sense the low-pass filter output signal (r) and BB Out, as shown in FIG. 8 and choose the mode of operation of the wireless receiver 24. The processor 94 may implement a correlation of the known preamble with the baseband output (BB Out).

[0081] The amplifier 88 is configured to receive the filtered envelope from the LPF 86 and to output a signal to the multiplexer 90. The input to the amplifier 88 labelled “Min. req. Amplitude” 96 is a user-defined or equipment defined input which determines the required amplitude of the IF signal for the wireless receiver 24 to be able to decode the data in a signal received by the wireless receiver 24. The low-pass filter 86 may be designed to dominate the effect of circuit dynamics due to the formed feedback loop between the Vbias and (r).

[0082] The operating principles of the QWG 92 are known and are not described herein.

[0083] Different operations for the control circuitry 60 corresponding to different modes of operation for the wireless receiver 24 may include one or more of the following:

[0084] For the wireless receiver 24 to be set to “linear” mode: a. The selection of the multiplexer 90 is set to the output of amplifier 88, which means that Vbias will be set to the amplifier output voltage value; and / or b. (r) reaches the minimum required amplitude without incurring any oscillations as long as Pin, the input power, is above a certain value.

[0085] For the wireless receiver 24 to be set to “super regenerative oscillator (SRO)” mode: c. The amplifier 86 will be turned off by the processor 94 and the multiplexer selection is set to the output of quench waveform generator 92, which means that the Vbias value will be set to the quench waveform generator output voltage; and / or d. The wireless receiver 24 may be configured to remain in this mode as long as Pin is below a certain value.

[0086] Plinear min may be set to achieve a best sensitivity that may be obtained by the RX operating in linear mode.

[0087] To further explain the functionality of the control circuitry 60, assume the following example. Consider the wireless receiver 24 initially set to “linear” mode and suppose that Pin falls below a certain value (Piinear min). Then, Vbias gets adjusted automatically through the closed loop and (r) reaches the minimum required amplitude, but the processor 94 detects oscillations in the output of the IMN 26 using preamble match. Then, the processor 94 may turn off the amplifier 88, turn on the QWG 92, and activate “super regenerative oscillator (SRO)” mode. Now suppose, Pin rises above a certain value (Piinear min). Then, the processor 94 detects that (r) is above a certain threshold value and turns off the QWG 92, turns on the amplifier 88 and activates “linear” mode. The illustration of switching between the receiver modes corresponding to the input signal strength is shown in the flowchart of FIG. 9. Assume the wireless receiver 24 is in the linear mode of operation (Block S20). If the preamble of the received signal matches a locally generated preamble (Block S22), then the wireless receiver 24 continues to operate in the linear mode. If the preamble of the received signal does not match the locally generated preamble then the amplifier 88 is turned off and the QWG 92 is turned on and the wireless receiver 24 switches to SRO mode (Block S26). If the received signal power does not exceed a threshold (Block S28), then the wireless receiver 24 continues operation in the SRO mode (Block S30). Otherwise, the QWG 92 is turned off, the amplifier 88 is turned on (Block S32).

[0088] The transitions in Vbias with respect to changes in the input signal strength are shown in FIG. 10

[0089] Additional embodiment: channel-selection enablement.

[0090] In some embodiments, it is possible to enable channel-selection in the wireless receiver 24 by introducing a varactor or programmable capacitor in the IMN LC tank 72. This results in center frequency tunability of the wireless receiver 24. To illustrate this center frequency tunability simulations have been performed using the same setup described above, while varying the capacitor in the LC tank 72 from 15fF to 19fF. The corresponding graph is shown in FIG. 11.

[0091] It may be seen that the center frequency is linearly tuned from 5.46GHz to 5.64GHz by varying the capacitors values from 19fF to 15fF.

[0092] Some example embodiments for an implementation of a wireless receiver featuring a multimode input matching network and associated control circuit are described as follows.

[0093] Embodiment 1. A wireless receiver including: a. an oscillator generates the local carrier frequency (LO) which is fed to a down-conversion mixer; b. a baseband circuit; c. a controllable multimode input matching network (IMN); and d. a control circuit to select the mode of operation of the multimode input matching network of Embodiment l.c.

[0094] Embodiment 2. The selection of the IMN operation mode depends on the signal strength at the input of the IMN, detected at the down-converted signal.

[0095] Embodiment 3. The controllable multimode input matching network may be implemented by an LC resonator and a controllable negative- gmcircuit.

[0096] Embodiment 4. The associated control circuit to select the mode of operation of the multimode input matching network. Embodiment 5. The control circuit may include a. A digital processor b. A multiplexer (mux) c. A quench waveform generator (QWG) d. An operational amplifier (op-amp) e. An integrator

[0097] Embodiment 6. The controllable multimode input matching network may further include: a. A tunable or programmable capacitor to be able to select / tune the frequency of maximum sensitivity / gain, i.e. the resonance frequency of the IMN.

[0098] As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and / or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and / or functionality described herein may be performed by, and / or associated to, a corresponding module, which may be implemented in software and / or firmware and / or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that may be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

[0099] Some embodiments are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0100] These computer program instructions may also be stored in a computer readable memory or storage medium that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0101] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0102] It is to be understood that the functions / acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality / acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0103] Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the “C” programming language. The program code may execute entirely on the user’s computer, partly on the user’s computer, as a stand-alone software package, partly on the user’s computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user’s computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0104] Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments may be combined in any way and / or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

[0105] Abbreviations that may be used in the preceding description include: Abbreviation Explanation

[0106] BB Baseband

[0107] CMOS Complementary Metal-Oxide Semiconductor fclk Clock Frequency gm transconductance

[0108] IF Intermediate Frequency

[0109] IMN Input Matching Network

[0110] LO Local Oscillator

[0111] LPF Low Pass Filter

[0112] Mux Multiplexer

[0113] Op-amp Operational Amplifier

[0114] PDK Process Design Kit

[0115] Q-factor Quality Factor

[0116] QWG Quench Waveform Generator

[0117] RF Radio Frequency

[0118] RX Receiver

[0119] SNR Signal-to-noise-ratio

[0120] SRO Super Regenerative Oscillator

[0121] It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

Claims:

1. A wireless receiver (24) configurable to operate in a linear mode or in a super- regenerative oscillating, SRO, mode, the wireless receiver (24) comprising: an input matching network (26) comprising: a resonance circuit (72) configured to resonate at a resonant frequency; and a tunable negative transconductance circuit (74) in communication with the resonance circuit (72) and configured to alter a Q-factor of the resonance circuit (72); and control circuitry (60) in communication with the input matching network (26) and configured to generate a bias voltage to the tunable negative transconductance circuit (74) to control when the wireless receiver (24) operates in the linear mode and when the wireless receiver (24) operates in the SRO mode.

2. The wireless receiver (24) of Claim 1, wherein the wireless receiver (24) is configured to operate in a linear mode when a power of a signal received by the wireless receiver (24) is within a first range and to switch to operating in the SRO mode when an output of the input matching network (26) oscillates.

3. The wireless receiver (24) of Claim 1, wherein the wireless receiver (24) is configured to operate in the linear mode until oscillations are detected in an output of the input matching network (26) and configured to operate in the SRO mode until the received signal power exceeds a first threshold.

4. The wireless receiver (24) of Claim 1, wherein the control circuitry (60) is configured to switch to the SRO mode when oscillations are detected in an output of the input matching network (26).

5. The wireless receiver (24) of Claim 4, wherein the wireless receiver (24) is configured to switch to the linear mode when the received signal power exceeds a first threshold.

6. The wireless receiver (24) of Claim 1, wherein the control circuitry (60) includes switching circuitry configured to select between first circuitry configured to generate a first bias voltage to configure the tunable negative transconductance circuit (74) to operate the wirelessreceiver (24) in the linear mode and second circuitry configured to generate a second bias voltage to configure the tunable negative transconductance circuit (74) to operate the wireless receiver (24) in the SRO mode.

7. The wireless receiver (24) of any of Claims 1-6, wherein the control circuitry (60) includes an amplifier configured to amplify the difference between a filtered envelope signal and a target envelope value and includes a quench waveform generator, QWG (92), configured to generate a waveform that alternates between two states until a threshold received signal power is reached.

8. The wireless receiver (24) of any of Claims 1-7, wherein, when operating in the linear mode, the input matching network (26) is configured to control a gain of the wireless receiver (24) to provide a minimum signal strength at a baseband output.

9. The wireless receiver (24) of any of Claims 1-8, wherein the SRO mode is activated when a signal strength at a baseband output falls below a second threshold when operating in the linear mode.

10. The wireless receiver (24) of any of Claims 1-9, wherein the input matching network further comprises a variable or programmable capacitor configured to tune a resonant frequency of the resonance circuit (72).

11. A wireless device (22) comprising the wireless receiver (24) of any of Claims 1- 10.

12. A method in a wireless receiver (24) , the method comprising: while operating (S10) the wireless receiver (24) in a linear mode: continuing to operate (SI 2) the wireless receiver (24) in the linear mode as long as a preamble of a signal received by the wireless receiver (24) matches a predetermined preamble; and when the preamble no longer matches the predetermined preamble, switching to operating (SI 4) the wireless receiver(24) in a super-regenerative oscillating, SRO, mode; and while operating (SI 6) the wireless receiver (24) in the SRO mode:continuing to operate (SI 8) the wireless receiver (24) in the SRO mode until a power of the received signal exceeds a first threshold; and when the received signal power exceeds the first threshold, switching to operating (S20) the wireless receiver (24) in the linear mode.

13. The method of Claim 19, further comprising switching from the linear mode to the SRO mode when oscillations are detected in an output of an input matching network (26) of the wireless receiver (24).

14. The method of Claim 12 , further comprising, when operating in the linear mode, configuring the input matching network (26) to control a gain of the wireless receiver (24) to provide a minimum signal strength at a baseband output of the wireless receiver (24).

15. The method of any of Claims 12 and 13, further comprising, when operating in the linear mode, switching to operating the wireless receiver (24) in the SRO mode when a signal strength of a baseband output of the wireless receiver (24) falls below a second threshold.

16. The method of any of Claims 12-14, further comprising, when operating in the SRO mode providing a bias voltage to the input matching network (26) that alternates between two states.

17. A wireless receiver (24), the wireless receiver (24) configured to: while operating (S10) in a linear mode: continuing to operate (SI 2) in the linear mode as long as a preamble of a signal received by the wireless receiver (24) matches a predetermined preamble; and when the preamble no longer matches the predetermined preamble, switching to operating (SI 4) in a super-regenerative oscillating, SRO, mode; and while operating (SI 6) in the SRO mode: continuing to operate (SI 8) in the SRO mode until a power of the received signal exceeds a first threshold; and when the received signal power exceeds the first threshold, switching to operating (S20) in the linear mode.

18. The wireless receiver (24) of Claim 16, wherein the wireless receiver (24) includes an input matching network (26) and is further configured to switch from the linear mode to the SRO mode when oscillations are detected in an output of the input matching network (26).

19. The wireless receiver (24) of Claim 17, wherein the wireless receiver (24) is further configured, when operating in the linear mode, configure the input matching network (26) to control a gain of the wireless receiver (24) to provide a minimum signal strength at a baseband output of the wireless receiver (24).

20. The wireless receiver (24) of any of Claims 17 and 18, wherein the wireless receiver (24) is configured to, when operating in the linear mode, switch to operating the wireless receiver (24) in the SRO mode when a signal strength of a baseband output of the wireless receiver (24) falls below a second threshold.

21. The wireless receiver (24) of any of Claims 17-19, wherein the wireless receiver (24) is configured to, when operating in the SRO mode providing a bias voltage to the input matching network (26) that alternates between two states.

22. A wireless device (22) comprising the wireless receiver (24) of any of Claims 17-21.

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