Remote control system using different types of carrier waves for polling signals

A carrier wave is selected based on a state of a target device such as a vehicle. A polling signal is generated using the selected carrier wave for transmission from the target device for receipt by a portable controller. A sinusoidal carrier wave is selected when the target device is in a state that is more sensitive to electrical noise interference caused by the polling signal being generated using the carrier wave than to electrical energy consumed in generating the polling signal using the carrier wave. A non-sinusoidal periodic carrier wave is selected when the target device is in a state that is more sensitive to electrical energy consumed in generating the polling signal using the carrier wave than to electrical noise interference caused by the polling signal being generated using the carrier wave.

TECHNICAL FIELD

The present disclosure relates to remote control systems including passive entry passive start (PEPS) systems.

BACKGROUND

Passive entry passive start (PEPS) systems include a base station and a portable remote controller. The base station is at a target device such as a vehicle. The remote controller is carried by a user. The base station and the remote controller wirelessly communicate with one another for remote control of the target device.

SUMMARY

A method includes selecting a carrier wave based on a state of a target device and generating a polling signal using the selected carrier wave for transmission from the target device for receipt by a portable controller.

The step of selecting may include selecting a sinusoidal carrier wave when the target device is in a state that is more sensitive to electrical noise interference caused by the polling signal being generated using the carrier wave than to electrical energy consumed in generating the polling signal using the carrier wave.

The step of selecting may include selecting a non-sinusoidal periodic carrier wave when the target device is in a state that is more sensitive to electrical energy consumed in generating the polling signal using the carrier wave than to electrical noise interference caused by the polling signal being generated using the carrier wave.

A method includes selecting, at a base station of a vehicle, a type of carrier wave from different types of carrier waves based on a state of the vehicle and transmitting, from the base station, a polling signal generated from a carrier wave of the selected type for receipt by a portable controller.

The different types of carrier waves may include a sinusoidal carrier wave and one or more different types of non-sinusoidal periodic carrier waves. The one or more different types of non-sinusoidal periodic carrier waves may include a square carrier wave and a triangle carrier wave.

The step of selecting may include: selecting a sinusoidal carrier wave when the vehicle state is a key on vehicle state; selecting a sinusoidal carrier wave when the vehicle state is an accessory mode vehicle state; and selecting a non-sinusoidal periodic carrier wave when the vehicle state is a key off vehicle state.

The state of the vehicle may include a first vehicle state and a second vehicle state. In this case, the step of selecting may include: selecting a sinusoidal carrier wave when the state of the vehicle is the first vehicle state; and selecting a non-sinusoidal periodic carrier wave when the state of the vehicle is the second vehicle state.

A system includes a base station at a target device. The base station is configured to detect a state of the target device, select a type of carrier wave from different types of carrier waves based on the state of the target device, generate a polling signal using a carrier wave of the selected type, and transmit the polling signal for receipt by a portable controller.

DETAILED DESCRIPTION

Referring now toFIG. 1, a block diagram of a remote control system10is shown. Remote control system10includes a base station12and a portable remote controller14. Base station12is at a target device such as a vehicle16. Alternatively, the target device is a house, a garage, a gate, a building, a door, a lighting system, or the like. Remote controller14is a portable device such as a key fob (“fob”)14to be carried by a user. Alternatively, the remote controller is a smart phone, a tablet, a wearable device such as a smart watch, or the like.

Base station12is configured to be able to control functions of vehicle16(i.e., the target device). Base station12and fob14(i.e., the remote controller) are operable for wirelessly transmitting/receiving signals to/from one another to enable the fob to remotely control vehicle16via the base station.

Remote control system10is configured to perform passive entry passive start (PEPS) functions. PEPS capability enables fob14to remotely control vehicle16automatically (or “passively”) without user actuation of the fob. As an example of a passive entry function, base station12unlocks a vehicle door in response to fob14being brought into the vicinity of vehicle16. As an example of a passive start function, base station12starts vehicle16upon a user in possession of fob14pressing a start button on the vehicle dashboard.

Remote control system10may be further configured to perform remote keyless entry (RKE) functions. RKE capability enables fob14to remotely control vehicle16in response to user actuation of buttons or the like of the fob. As an example of a RKE function, base station12unlocks a door of vehicle16in response to receiving a vehicle door unlock command from fob14. Fob14transmits the vehicle door unlock command to base station12in response to corresponding user actuation of the fob.

As shown inFIG. 1, base station12includes a transmitter18and a receiver20. Base station transmitter18is operable for transmitting signals to fob14and base station receiver20is operable for receiving signals from the fob. Correspondingly, fob14includes a receiver22and a transmitter24. Fob receiver22is operable for receiving signals from base station12and fob transmitter24is operable for transmitting signals to the base station.

The signals transmitted from base station transmitter18for receipt by fob14include polling signals. Base station transmitter18transmits polling signals as part of the processes for certain types of PEPS or other remote control operations. For example, base station transmitter18transmits polling signals to poll or interrogate the area around vehicle16for any fobs. Upon fob14receiving a polling signal from base station transmitter18, fob14wakes up and responds somehow. For instance, fob14transmits an authentication signal including a command signal for receipt by base station12. The base station performs the command function in response to receiving the authentication signal with the command function from fob14. In this way, the command function is performed passively without user actuation of fob14.

Referring now toFIG. 2, with continual reference toFIG. 1, a block diagram of base station transmitter18is shown. This block diagram includes a depiction of the operation of base station transmitter18in generating a polling signal26. Base station transmitter18includes a processor28, a carrier wave generator30(or “driver”), and a frequency mixer32. Processor28is configured for providing an information signal34. Information signal34is in the form of digital data, which may employ Manchester encoding. The digital data represents the information of information signal34. The information includes information identifying information signal34as forming a polling signal from base station12. For instance, the information includes a wake up pattern and a message stating that information signal34is a polling signal and that a fob in receipt of the polling signal should respond in some way.

Carrier wave generator30is configured for generating a carrier wave36. Carrier wave36is to be modulated with information signal34to form polling signal26. The modulation of carrier wave36with information signal34is for the purpose of wirelessly transmitting the information signal in the form of polling signal26. As such, carrier wave36has an appropriate wireless communication carrier frequency. For instance, the carrier frequency of carrier wave36falls within a low-frequency (LF) operating frequency range between 20 to 300 kHz. In this way, polling signal26is a LF polling signal. LF polling signals are typically used for polling because such signals only radiate a short distance. The carrier frequency of carrier wave36could be any frequency falling within the radio-frequency (RF) band and carrier wave generator30is operable for generating the carrier wave with any of such frequencies. As such, polling signal26may be a non-LF polling signal.

Carrier wave generator30is operable to generate carrier wave36in a selected one of various wave forms. For instance, carrier wave generator30may generate carrier wave36as a sinusoidal carrier wave during a time period and may generate carrier wave36as a non-sinusoidal periodic carrier wave during a different time period. The non-sinusoidal periodic carrier wave may be a square carrier wave, a triangle carrier wave, a saw-tooth carrier wave, etc. In general, carrier wave generator30is able to generate carrier wave36in any user-defined wave form.

Mixer32receives information signal34from processor28and carrier wave36from carrier wave generator30. Mixer32modulates carrier wave36with information signal34to generate polling signal26. Polling signal26is then ready for transmission from base station transmitter18. Base station transmitter18is associated with one or more antennas (not shown) positioned at respective locations of vehicle16(e.g., center console, right vehicle door, left vehicle door, trunk). Polling signal26is transmitted from the one or more antennas for receipt by fob14.

Base station transmitter18typically generates and transmits a periodic train of polling signals26until either fob14responds to a polling signal or a time out event expires. Base station transmitter18is operable to set the time duration of each polling signal26and the amount of polling signals26in a given time period based on various factors. For instance, such factors include how fast a user carrying fob14could be approaching vehicle16and how far from the vehicle it is desirable to detect the user.

As indicated, carrier wave generator30can generate carrier wave36in any of selected ones of sinusoidal wave forms and non-sinusoidal periodic wave forms. The sinusoidal wave forms include a sine wave. The non-sinusoidal periodic wave forms include a square wave, as well as a triangle wave, a saw-tooth wave, and the like.

A carrier wave36having a sinusoidal wave form and a carrier wave36having a non-sinusoidal periodic wave form have advantages and disadvantages with one another in regards to electrical power (i.e., current) consumption and electrical noise interference (e.g., electro-magnetic interference (EMI)). A carrier wave36having a sinusoidal wave form requires more electrical current consumption for it to be generated than a carrier wave36having a non-sinusoidal periodic wave form—less electrical current consumption is an advantage of a carrier wave36having a non-sinusoidal periodic wave form compared with a carrier wave36having a sinusoidal wave form. A carrier wave36having a sinusoidal wave form produces less electrical noise interference than a carrier wave36having a non-sinusoidal periodic wave form—less electrical noise interference is an advantage of a carrier wave36having a sinusoidal wave form compared with a carrier wave36having a non-sinusoidal periodic wave form.

In particular, a carrier wave36having a sine wave form requires the most amount of electrical current consumption for its generation, but produces the least amount of electrical noise; a carrier wave36having a square wave form requires the least amount of electrical current consumption for its generation, but produces the greatest amount of electrical noise; and a carrier wave36having a triangle wave form requires an intermediate amount of electrical current consumption for its generation and produces an intermediate amount of electrical noise.

Accordingly, base station transmitter18consumes less electrical current to generate polling signals26with a non-sinusoidal periodic carrier wave36(e.g., a square carrier wave) than with a sinusoidal carrier wave36(e.g., a sine carrier wave). Thus, less electrical energy will be consumed from the electrical energy source (i.e., the vehicle battery) when base station transmitter18transmits polling signals26with a square carrier wave36than with a sine carrier wave36. However, polling signals26with a square carrier wave36produce more electrical noise interference than polling signals with a sine carrier wave36. Thus, a tradeoff exists between electrical power consumption and electrical noise interference when carrier wave generator30uses a square carrier wave36or a sine carrier wave36for polling signals26.

Base station12takes advantage of the tradeoff between electrical power consumption and electrical noise interference when transmitting polling signals26. Base station12takes advantage of the tradeoff by transmitting polling signals26with a non-sinusoidal periodic carrier wave36(e.g., a square carrier wave36) during states of vehicle16in which the reduced electrical current consumption associated with the square carrier wave is valued more than the electrical noise interference associated with the square carrier wave. For instance, when vehicle16is in an “off” state (e.g., the vehicle engine is shut off and the vehicle is parked and is not being operated by a driver), a requested polling operation is likely to be relatively long term and electrical noise interference with vehicle accessories is not a concern as the vehicle is not being used. Thus, when polling is requested while vehicle16is in this “off” state, base station transmitter18transmits polling signals26with square carrier wave36to minimize electrical current consumption as it is desired to achieve polling at the lowest achievable electrical current consumption while the vehicle is in the “off” state.

Correspondingly, base station12takes advantage of the tradeoff by transmitting polling signals26with a sinusoidal carrier wave36(e.g., a sine carrier wave36) during other states of vehicle16in which the reduced electrical noise interference associated with the sine carrier wave is valued more than electrical current consumption associated with the sine carrier wave. For instance, when vehicle16is in an “on” state (e.g., the vehicle is being operated or driven by a driver), any requested polling operation will be relatively short term and electrical noise interference with vehicle accessories is a concern as the vehicle is being used by a user. Thus, when polling is requested while vehicle16is in this “on” state, base station transmitter18transmits polling signals26with sine carrier wave36to minimize electrical noise interference as a user may be using vehicle accessories (e.g., the AM radio).

In operation, carrier wave generator30outputs a non-sinusoidal periodic carrier wave36(e.g., a square carrier wave36) or a sinusoidal carrier wave36(e.g., a sine carrier wave36) depending on the state of vehicle16. The selected type of carrier wave36is used to generate polling signals26. That is, when polling is requested for whatever remote control or PEPS operation, carrier wave generator30generates carrier wave36for polling signals26using a square carrier wave (or a triangle carrier wave, a stair-step carrier wave, or some other non-sinusoidal periodic carrier wave) or a sine carrier wave depending on the state of vehicle16.

Carrier wave generator30includes an input to receive vehicle state information38. Vehicle state information38may be indicative of the following states of vehicle16: (i) a “key off” vehicle state in which vehicle16is parked with the vehicle engine and the vehicle accessory mode being off; (ii) a “key on” vehicle state in which the vehicle engine is on and vehicle accessories (e.g., the vehicle radio) may be on; and (iii) an “accessory mode” vehicle state in which the vehicle engine is off, but vehicle accessories (e.g., the vehicle radio) may be on.

In the key off vehicle state, carrier wave generator30generates a square carrier wave36for polling signals26. Carrier wave generator30generates square carrier wave36for polling signals26as (i) the disadvantage of more electrical noise interference associated with the square carrier wave is not a concern whereas (ii) the advantage of less electrical consumption associated with generating the square carrier wave is desired. In the key off vehicle state, electrical noise interference with the (AM) radio of vehicle16caused by carrier wave generator30in generating square carrier wave36is not a concern as the radio is not being used. Thus, any electrical noise interference would not be perceived by a user as the user is not listening to the radio. On the other hand, in the key off vehicle state, minimizing electrical energy used by base station transmitter18in transmitting polling signals26is desired as the vehicle may be off for a relatively long time (e.g., parked in a parking lot during the day or a driveway during the night/weekend) with the electrical energy being provided by the vehicle battery. That is, the polling process requested by the remote control or PEPS operation likely entails a relatively long polling duration as the vehicle may not be used for some time.

In the key on vehicle state, carrier wave generator30generates sine carrier wave36for polling signals26. Carrier wave generator30generates sine carrier wave36as (i) the disadvantage of more electrical consumption associated with the sine carrier wave is not a concern whereas (ii) the advantage of less electrical noise interference associated with the sine carrier wave is desired. In the key on vehicle state, more electrical energy consumption associated with the sine carrier wave is not a concern as the polling process requested by the remote control or PEPS operation likely entails a relatively short polling duration and/or as the vehicle battery can be replenished as the vehicle is being driven. On the other hand, in the key on vehicle state, minimizing electrical noise interference with the radio of vehicle16caused by carrier wave generator30in generating sine carrier wave36is desired. Minimizing the electrical noise interference is desired as the user will likely listen to the radio at some point while the vehicle is in the key on vehicle state.

In the accessory mode vehicle state, carrier wave generator30generates sine carrier wave36for polling signals26. Carrier wave generator30generates sine carrier wave36as (i) the disadvantage of more electrical consumption associated with the sine carrier wave is not a concern whereas (ii) the advantage of less electrical noise interference associated with the sine carrier wave is desired. In the accessory mode vehicle state, more electrical energy consumption associated with the sine carrier wave is not a concern as the polling process requested by the remote control or PEPS operation likely entails a relatively short polling duration and/or as the user is likely to soon change the accessory mode vehicle state to either the key off vehicle state or the key on vehicle state. On the other hand, in the accessory mode vehicle state, minimizing electrical noise interference with the radio of vehicle16caused by carrier wave generator30in generating sine carrier wave36is desired. Minimizing the electrical noise interference is desired as the user may likely listen to the radio at some point while the vehicle is in the accessory mode vehicle state. In some cases, the user may have specifically enabled the accessory mode just to listen to the radio for a brief period.

Referring now toFIG. 3, with continual reference toFIGS. 1 and 2, a flowchart40depicting operation of base station transmitter18using different types of carrier waves for transmitting polling signals26is shown. The operation commences upon base station transmitter18receiving a request for transmitting polling signals26as indicated in block42. Carrier wave generator30then detects the vehicle state as indicated in block44. When the vehicle state is key off as indicated in block46, carrier wave generator30generates a non-sinusoidal periodic carrier wave36(e.g., a square carrier wave36) for generating polling signals26as indicated in block48. When the vehicle state is either key on or accessory mode, as indicated in blocks50and52, respectively, carrier wave generator30generates a sinusoidal carrier wave36(e.g., a sine carrier wave36) for generating polling signals26as indicated in block54.

As described, the sine wave driver capability of carrier wave generator30is used for PEPS systems in order to reduce electrical noise interference from the carrier wave generator to vehicle systems such as the AM radio in vehicle16. For temporary or on-demand polling operations of a relatively short duration, the sine wave driver capability works well. However, the sine wave driver capability is associated with a relatively higher operating current. Thus, for long term polling operations (i.e., during the key off vehicle state), the sine wave driver capability requires relatively more electrical consumption. In order to achieve the advantages of both of a sine wave driver and a square wave (or quasi square wave) driver, carrier wave generator30uses these different types of drivers, but in different situations.

Carrier wave generator30has the ability to operate as any of different types of drivers including sine wave, square wave, user-defined waves that could be something between the sine wave and the square wave (i.e., triangle wave, stair-step wave, etc.). Carrier wave generator30generates a square carrier wave for long term polling applications and generates a sine carrier wave for short term polling applications. This dual approach works well as a sine carrier wave is used for fob searches when the vehicle radio is on whereas a square carrier wave is only used for fob searches during key off conditions. Another advantage of the square wave driver is the ability to increase the antenna current beyond the sine carrier wave capability of carrier wave generator30.