Patent Publication Number: US-11386750-B2

Title: Linked communications for gaming systems using acoustic signatures

Description:
RELATED APPLICATION 
     This patent application is a continuation of U.S. patent application Ser. No. 16/682,274, filed Nov. 13, 2019, which is a continuation of U.S. patent application Ser. No. 16/140,932 filed Sep. 25, 2018 (issued as U.S. Pat. No. 10,510,207), which claims the priority benefit of U.S. Provisional Patent Application No. 62/563,759 filed Sep. 27, 2017, the contents of each application are incorporated herein by reference in their entirety. 
    
    
     COPYRIGHT 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. Copyright 2021 SG Gaming, Inc. 
     FIELD OF THE INVENTION 
     The present invention relates generally to gaming systems, apparatus, and methods and, more particularly, to gaming systems using acoustic signals for establishing and/or maintaining communications with mobile user devices. 
     BACKGROUND OF THE INVENTION 
     Wagering game machines, such as slot machines, video poker machines and the like, have been a cornerstone of the gaming industry for several years. Generally, the popularity of such machines depends on the likelihood (or perceived likelihood) of winning money at the machine and the intrinsic entertainment value of the machine relative to other available gaming options. Where the available gaming options include a number of competing wagering game machines and the expectation of winning at each machine is roughly the same (or believed to be the same), players are likely to be attracted to the most entertaining and exciting machines. Shrewd operators consequently strive to employ the most entertaining and exciting machines, features, and enhancements available because such machines attract frequent play and hence increase profitability to the operator. Therefore, there is a continuing need for wagering game machine manufacturers to continuously develop new features and/or functionality that will attract frequent play. 
     At least some manufacturers may provide at least some features to a player using mobile user devices (also sometimes referred to herein as “mobile devices”) carried or worn by the player, such as smartphones and wearable electronics. For example, the player may provide credentials to a web or application interface to access player tracking features, bonus games, and the like. To match a player to a particular wagering game machine, the player may be required to manually pair the mobile user device with the wagering game machine. That is, the player provides user input via the mobile user device that identifies the wager game machine such that, during a gaming session, data associated with the player is transmitted to the game machine and/or data associated with the game machine is transmitted to the mobile user device. However, the pairing process may be cumbersome, time-consuming, and/or confusing to a player (e.g., the player or mobile user device is unable to properly identify the correct wagering game machine to pair with), which may lead to the player abandoning play of the game. Moreover, some communication methods used to establish communication between two computing devices may require particular components or modules to be installed at the wagering game machines that may be costly to add to new or existing game machines. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a gaming system comprises logic circuitry and a gaming machine for conducting a casino wagering game. The logic circuitry receives, via an acoustic input component of the gaming machine, an acoustic capture signal representative of a player account identifier corresponding to a player account and having distinctive capture characteristics from a mobile device, determines the player account identifier represented by the capture signal, and associates a gaming session on the gaming machine with the corresponding player account. In addition, the logic circuitry, in response to receiving in a prescribed manner, via the acoustic input component, an acoustic maintain-session signal having distinctive maintain-session characteristics from the mobile device, maintains the association between the gaming session on the gaming machine and the corresponding player account for a period of time. In response to failing to receive the maintain-session signal in the prescribed manner, the logic circuitry terminates the association between the gaming session on the gaming machine and the corresponding player account. The gaming system may be incorporated into a single, freestanding gaming machine. 
     According to another aspect of the invention, a method of operating a gaming system is provided. The gaming system includes logic circuitry and a gaming machine with an acoustic input component. The method is at least partially performed by the logic circuitry. The method includes receiving, via the acoustic input component, an acoustic capture signal including a player account identifier corresponding to a player account and having distinctive capture characteristics from a mobile device, reading the player account identifier contained within the capture signal, associating a gaming session on the gaming machine with the corresponding player account, and transmitting, to the corresponding player account, game-play information related to the gaming session on the gaming machine. 
     According to another aspect of the invention, a method of operating a gaming system is provided. The gaming system includes logic circuitry and a gaming machine having an acoustic input component. The method is at least partially performed by the logic circuitry. The method includes initiating a gaming session associated with a player account on the gaming machine, and in response to receiving in a prescribed manner, via the acoustic input component, a maintain-session signal having distinctive maintain-session characteristics from a mobile device, maintaining the association between the gaming session on the gaming machine and the player account for a period of time. The method further includes terminating, in response to failing to receive the maintain-session signal in the prescribed manner, the association between the gaming session on the gaming machine and the player account. 
     Additional aspects of the invention will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments, which is made with reference to the drawings, a brief description of which is provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a free-standing gaming machine according to an embodiment of the present invention. 
         FIG. 2  is a schematic view of a gaming system according to an embodiment of the present invention. 
         FIG. 3  is a schematic view of an example gaming system that includes an acoustic interface for establishing and maintain communication with mobile user devices according to an embodiment of the present invention. 
         FIG. 4  is a data flow diagram of a session-establishment process performed by the example gaming system shown in  FIG. 3 . 
         FIG. 5  is a flowchart of an example session-establishment process in accord with at least some aspects of the disclosed concepts. 
         FIG. 6  is a perspective view of device interface according to an embodiment of the invention. 
         FIG. 7  is a perspective view of a receiving component of the device interface shown in  FIG. 6  for receiving mobile user devices. 
         FIG. 8  is a data flow diagram of a maintain-session process performed by the example gaming system shown in  FIG. 3 . 
         FIG. 9  is a flowchart of an example maintain-session process in accord with at least some aspects of the disclosed concepts. 
         FIG. 10  is a flowchart of an example end-session process in accord with at least some aspects of the disclosed concepts. 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. For purposes of the present detailed description, the singular includes the plural and vice versa (unless specifically disclaimed); the words “and” and “or” shall be both conjunctive and disjunctive; the word “all” means “any and all”; the word “any” means “any and all”; and the word “including” means “including without limitation.” 
     As used herein, “audio” and “acoustic” refer to audible and inaudible (e.g., ultrasonic and infrasonic) tones and sound waves. “Audio signals” and “acoustic signals” are used interchangeably to refer to tones and sound waves generated electronically (i.e., by a computing device). Audio and acoustic signals as used herein not only refer to the electronic or digital form of the signals, but also the tones and sound waves emitted when the audio signals are provided to an acoustic output component (e.g., a speaker). 
     For purposes of the present detailed description, the terms “wagering game,” “casino wagering game,” “gambling,” “slot game,” “casino game,” and the like include games in which a player places at risk a sum of money or other representation of value, whether or not redeemable for cash, on an event with an uncertain outcome, including without limitation those having some element of skill. In some embodiments, the wagering game involves wagers of real money, as found with typical land-based or online casino games. In other embodiments, the wagering game additionally, or alternatively, involves wagers of non-cash values, such as virtual currency, and therefore may be considered a social or casual game, such as would be typically available on a social networking web site, other web sites, across computer networks, or applications on mobile devices (e.g., phones, tablets, etc.). When provided in a social or casual game format, the wagering game may closely resemble a traditional casino game, or it may take another form that more closely resembles other types of social/casual games. 
     Referring to  FIG. 1 , there is shown a gaming machine  10  similar to those operated in gaming establishments, such as casinos. With regard to the present invention, the gaming machine  10  may be any type of gaming terminal or machine and may have varying structures and methods of operation. For example, in some aspects, the gaming machine  10  is an electromechanical gaming terminal configured to play mechanical slots, whereas in other aspects, the gaming machine is an electronic gaming terminal configured to play a video casino game, such as slots, keno, poker, blackjack, roulette, craps, etc. The gaming machine  10  may take any suitable form, such as floor-standing, models as shown, handheld mobile units, bartop models, workstation-type console models, etc. Further, the gaming machine  10  may be primarily dedicated for use in playing wagering games, or may include non-dedicated devices, such as mobile phones, personal digital assistants, personal computers, etc. Exemplary types of gaming machines are disclosed in U.S. Pat. Nos. 6,517,433, 8,057,303, and 8,226,459, which are incorporated herein by reference in their entireties. 
     The gaming machine  10  illustrated in  FIG. 1  comprises a gaming cabinet  12  that securely houses various input devices, output devices, input/output devices, internal electronic/electromechanical components, and wiring. The cabinet  12  includes exterior walls, interior walls and shelves for mounting the internal components and managing the wiring, and one or more front doors that are locked and require a physical or electronic key to gain access to the interior compartment of the cabinet  12  behind the locked door. The cabinet  12  forms an alcove  14  configured to store one or more beverages or personal items of a player. A notification mechanism  16 , such as a candle or tower light, is mounted to the top of the cabinet  12 . It flashes to alert an attendant that change is needed, a hand pay is requested, or there is a potential problem with the gaming machine  10 . 
     The input devices, output devices, and input/output devices are disposed on, and securely coupled to, the cabinet  12 . By way of example, the output devices include a primary display  18 , a secondary display  20 , and one or more audio speakers  22 . The primary display  18  or the secondary display  20  may be a mechanical-reel display device, a video display device, or a combination thereof in which a transmissive video display is disposed in front of the mechanical-reel display to portray a video image superimposed upon the mechanical-reel display. The displays variously display information associated with wagering games, non-wagering games, community games, progressives, advertisements, services, premium entertainment, text messaging, emails, alerts, announcements, broadcast information, subscription information, etc. appropriate to the particular mode(s) of operation of the gaming machine  10 . The gaming machine  10  includes a touch screen(s)  24  mounted over the primary or secondary displays, buttons  26  on a button panel, a bill/ticket acceptor  28 , a card reader/writer  30 , a ticket dispenser  32 , and player-accessible ports (e.g., audio output jack for headphones, video headset, jack, USB port, wireless transmitter/receiver, etc.). It should be understood that numerous other peripheral devices and other elements exist and are readily utilizable in any number of combinations to create various forms of a gaming machine in accord with the present concepts. 
     The player input devices, such as the touch screen  24 , buttons  26 , a mouse, a joystick, a gesture-sensing device, a voice-recognition device, and a virtual-input device, accept player inputs and transform the player inputs to electronic data signals indicative of the player inputs, which correspond to an enabled feature for such inputs at a time of activation (e.g., pressing a “Max Bet” button or soft key to indicate a player&#39;s desire to place a maximum wager to play the wagering game). The inputs, once transformed into electronic data signals, are output to game-logic circuitry for processing. The electronic data signals are selected from a group consisting essentially of an electrical current, an electrical voltage, an electrical charge, an optical signal, an optical element, a magnetic signal, and a magnetic element. 
     The gaming machine  10  includes one or more value input/payment devices and value output/payout devices. In order to deposit cash or credits onto the gaming machine  10 , the value input devices are configured to detect a physical item associated with a monetary value that establishes a credit balance on a credit meter. The physical item may, for example, be currency bills, coins, tickets, vouchers, coupons, cards, and/or computer-readable storage mediums. The deposited cash or credits are used to fund wagers placed on the wagering game played via the gaming machine  10 . That is, wagers decrease or draw upon the credit balance. Conversely, awards from play of a wagering game may increase the credit balance. Examples of value input devices include, but are not limited to, a coin acceptor, the bill/ticket acceptor  28 , the card reader/writer  30 , a wireless communication interface for reading cash or credit data from a nearby mobile device, and a network interface for withdrawing cash or credits from a remote account via an electronic funds transfer. In response to a cashout input that initiates a payout from the credit balance on the “credits” meter, the value output devices are used to dispense cash or credits from the gaming machine  10 . The credits may be exchanged for cash at, for example, a cashier or redemption station. Examples of value output devices include, but are not limited to, a coin hopper for dispensing coins or tokens, a bill dispenser, the card reader/writer  30 , the ticket dispenser  32  for printing tickets redeemable for cash or credits, a wireless communication interface for transmitting cash or credit data to a nearby mobile device, and a network interface for depositing cash or credits to a remote account via an electronic funds transfer. 
     Turning now to  FIG. 2 , there is shown a block diagram of the gaming-machine architecture. The gaming machine  10  includes game-logic circuitry  40  securely housed within a locked box inside the gaming cabinet  12  (see  FIG. 1 ). The game-logic circuitry  40  includes a central processing unit (CPU)  42  connected to a main memory  44  that comprises one or more memory devices. The CPU  42  includes any suitable processor(s), such as those made by Intel and AMD. By way of example, the CPU  42  includes a plurality of microprocessors including a master processor, a slave processor, and a secondary or parallel processor. Game-logic circuitry  40 , as used herein, comprises any combination of hardware, software, or firmware disposed in or outside of the gaming machine  10  that is configured to communicate with or control the transfer of data between the gaming machine  10  and a bus, another computer, processor, device, service, or network. The game-logic circuitry  40 , and more specifically the CPU  42 , comprises one or more controllers or processors and such one or more controllers or processors need not be disposed proximal to one another and may be located in different devices or in different locations. The game-logic circuitry  40 , and more specifically the main memory  44 , comprises one or more memory devices which need not be disposed proximal to one another and may be located in different devices or in different locations. The game-logic circuitry  40  is operable to execute all of the various gaming methods and other processes disclosed herein. For example, the game-logic circuitry  40  operates to execute a wagering-game program causing the primary display  18  or the secondary display  20  to display the wagering game. The main memory  44  includes a wagering-game unit  46 . In one embodiment, the wagering-game unit  46  causes wagering games to be presented, such as video poker, video black jack, video slots, video lottery, etc., in whole or part. 
     The game-logic circuitry  40  is also connected to an input/output (I/O) bus  48 , which can include any suitable bus technologies, such as an AGTL+ frontside bus and a PCI backside bus. The I/O bus  48  is connected to various input devices  50 , output devices  52 , and input/output devices  54  such as those discussed above in connection with  FIG. 1 . The I/O bus  48  is also connected to a storage unit  56  and an external-system interface  58 , which is connected to external system(s)  60  (e.g., wagering-game networks). 
     The external system  60  includes, in various aspects, a gaming network, other gaming machines or terminals, a gaming server, a remote controller, communications hardware, or a variety of other interfaced systems or components, in any combination. In yet other aspects, the external system  60  comprises a player&#39;s portable electronic device (e.g., cellular phone, electronic wallet, etc.) and the external-system interface  58  is configured to facilitate wireless communication and data transfer between the portable electronic device and the gaming machine  10 , such as by a near-field communication path operating via magnetic-field induction or a frequency-hopping spread spectrum RF signals (e.g., Bluetooth, etc.). 
     The gaming machine  10  optionally communicates with the external system  60  such that the gaming machine  10  operates as a thin, thick, or intermediate client. The game-logic circuitry  40 —whether located within (“thick client”), external to (“thin client”), or distributed both within and external to (“intermediate client”) the gaming machine  10 —is utilized to provide a wagering game on the gaming machine  10 . In general, the main memory  44  stores programming for a random number generator (RNG), game-outcome logic, and game assets (e.g., art, sound, etc.)—all of which obtained regulatory approval from a gaming control board or commission and are verified by a trusted authentication program in the main memory  44  prior to game execution. The authentication program generates a live authentication code (e.g., digital signature or hash) from the memory contents and compare it to a trusted code stored in the main memory  44 . If the codes match, authentication is deemed a success and the game is permitted to execute. If, however, the codes do not match, authentication is deemed a failure that must be corrected prior to game execution. Without this predictable and repeatable authentication, the gaming machine  10 , external system  60 , or both are not allowed to perform or execute the RNG programming or game-outcome logic in a regulatory-approved manner and are therefore unacceptable for commercial use. In other words, through the use of the authentication program, the game-logic circuitry facilitates operation of the game in a way that a person making calculations or computations could not. 
     When a wagering-game instance is executed, the CPU  42  (comprising one or more processors or controllers) executes the RNG programming to generate one or more pseudo-random numbers. The pseudo-random numbers are divided into different ranges, and each range is associated with a respective game outcome. Accordingly, the pseudo-random numbers are utilized by the CPU  42  when executing the game-outcome logic to determine a resultant outcome for that instance of the wagering game. The resultant outcome is then presented to a player of the gaming machine  10  by accessing the associated game assets, required for the resultant outcome, from the main memory  44 . The CPU  42  causes the game assets to be presented to the player as outputs from the gaming machine  10  (e.g., audio and video presentations). Instead of a pseudo-RNG, the game outcome may be derived from random numbers generated by a physical RNG that measures some physical phenomenon that is expected to be random and then compensates for possible biases in the measurement process. Whether the RNG is a pseudo-RNG or physical RNG, the RNG uses a seeding process that relies upon an unpredictable factor (e.g., human interaction of turning a key) and cycles continuously in the background between games and during game play at a speed that cannot be timed by the player, for example, at a minimum of 100 Hz (100 calls per second) as set forth in Nevada&#39;s New Gaming Device Submission Package. Accordingly, the RNG cannot be carried out manually by a human and is integral to operating the game. 
     The gaming machine  10  may be used to play central determination games, such as electronic pull-tab and bingo games. In an electronic pull-tab game, the RNG is used to randomize the distribution of outcomes in a pool and/or to select which outcome is drawn from the pool of outcomes when the player requests to play the game. In an electronic bingo game, the RNG is used to randomly draw numbers that players match against numbers printed on their electronic bingo card. 
     The gaming machine  10  may include additional peripheral devices or more than one of each component shown in  FIG. 2 . Any component of the gaming-machine architecture includes hardware, firmware, or tangible machine-readable storage media including instructions for performing the operations described herein. Machine-readable storage media includes any mechanism that stores information and provides the information in a form readable by a machine (e.g., gaming terminal, computer, etc.). For example, machine-readable storage media includes read only memory (ROM), random access memory (RAM), magnetic-disk storage media, optical storage media, flash memory, etc. 
     In accord with various methods of conducting a wagering game on a gaming system in accord with the present concepts, the wagering game includes a game sequence in which a player makes a wager and a wagering-game outcome is provided or displayed in response to the wager being received or detected. The wagering-game outcome, for that particular wagering-game instance, is then revealed to the player in due course following initiation of the wagering game. The method comprises the acts of conducting the wagering game using a gaming apparatus, such as the gaming machine  10  depicted in  FIG. 1 , following receipt of an input from the player to initiate a wagering-game instance. The gaming machine  10  then communicates the wagering-game outcome to the player via one or more output devices (e.g., primary display  18  or secondary display  20 ) through the display of information such as, but not limited to, text, graphics, static images, moving images, etc., or any combination thereof. In accord with the method of conducting the wagering game, the game-logic circuitry  40  transforms a physical player input, such as a player&#39;s pressing of a “Spin Reels” touch key, into an electronic data signal indicative of an instruction relating to the wagering game (e.g., an electronic data signal bearing data on a wager amount). 
     In the aforementioned method, for each data signal, the game-logic circuitry  40  is configured to process the electronic data signal, to interpret the data signal (e.g., data signals corresponding to a wager input), and to cause further actions associated with the interpretation of the signal in accord with stored instructions relating to such further actions executed by the controller. As one example, the CPU  42  causes the recording of a digital representation of the wager in one or more storage media (e.g., storage unit  56 ), the CPU  42 , in accord with associated stored instructions, causes the changing of a state of the storage media from a first state to a second state. This change in state is, for example, effected by changing a magnetization pattern on a magnetically coated surface of a magnetic storage media or changing a magnetic state of a ferromagnetic surface of a magneto-optical disc storage media, a change in state of transistors or capacitors in a volatile or a non-volatile semiconductor memory (e.g., DRAM, etc.). The noted second state of the data storage media comprises storage in the storage media of data representing the electronic data signal from the CPU  42  (e.g., the wager in the present example). As another example, the CPU  42  further, in accord with the execution of the stored instructions relating to the wagering game, causes the primary display  18 , other display device, or other output device (e.g., speakers, lights, communication device, etc.) to change from a first state to at least a second state, wherein the second state of the primary display comprises a visual representation of the physical player input (e.g., an acknowledgement to a player), information relating to the physical player input (e.g., an indication of the wager amount), a game sequence, an outcome of the game sequence, or any combination thereof, wherein the game sequence in accord with the present concepts comprises acts described herein. The aforementioned executing of the stored instructions relating to the wagering game is further conducted in accord with a random outcome (e.g., determined by the RNG) that is used by the game-logic circuitry  40  to determine the outcome of the wagering-game instance. In at least some aspects, the game-logic circuitry  40  is configured to determine an outcome of the wagering-game instance at least partially in response to the random parameter. 
     In one embodiment, the gaming machine  10  and, additionally or alternatively, the external system  60  (e.g., a gaming server), means gaming equipment that meets the hardware and software requirements for fairness, security, and predictability as established by at least one state&#39;s gaming control board or commission. Prior to commercial deployment, the gaming machine  10 , the external system  60 , or both and the casino wagering game played thereon may need to satisfy minimum technical standards and require regulatory approval from a gaming control board or commission (e.g., the Nevada Gaming Commission, Alderney Gambling Control Commission, National Indian Gaming Commission, etc.) charged with regulating casino and other types of gaming in a defined geographical area, such as a state. By way of non-limiting example, a gaming machine in Nevada means a device as set forth in NRS 463.0155, 463.0191, and all other relevant provisions of the Nevada Gaming Control Act, and the gaming machine cannot be deployed for play in Nevada unless it meets the minimum standards set forth in, for example, Technical Standards 1 and 2 and Regulations 5 and 14 issued pursuant to the Nevada Gaming Control Act. Additionally, the gaming machine and the casino wagering game must be approved by the commission pursuant to various provisions in Regulation 14. Comparable statutes, regulations, and technical standards exist in other gaming jurisdictions. As can be seen from the description herein, the gaming machine  10  may be implemented with hardware and software architectures, circuitry, and other special features that differentiate it from general-purpose computers (e.g., desktop PCs, laptops, and tablets). 
       FIG. 3  is a schematic diagram of an example gaming system  300  including a gaming machine  310  and an external game network  360 . The gaming machine  310  and game network  360  may be substantially similar to the gaming machine  10  and external system  60  (both shown in  FIG. 1 ), respectively, and absent contrary representation, include similar components and/or functionality. In other embodiments, the gaming system  300  includes additional, fewer, or alternative devices, including those described elsewhere herein. 
     In the example embodiment, the gaming machine  310  includes an acoustic interface  320 , a presence sensor  330 , and logic circuitry  340 , and the game network  360  includes network logic circuitry  362 . The network logic circuitry  362  may be similar to the logic circuitry  340 , and thus may perform one or more of the features and tasks performed by the logic circuitry  340  as described herein. The gaming machine  310  is communicatively coupled to the game network  360 . At least one of the gaming machine  310  or the game network  360  is communicatively coupled to a mobile device  302 . The mobile device  302  is a portable computing device (e.g., a laptop, tablet, a smartphone, a smart watch, a wearable electronic, etc.) associated with a player  301 . Communicatively coupling the mobile device  302  to the gaming machine  310  and/or the game network  360  may facilitate integration of the mobile device  302  with game play and/or other features provided by the gaming system  300 . 
     In at least some embodiments, a software application associated with the system  300  is stored on the mobile device  302  to provide the player  301  with features associated with the system  300 . For example, the mobile device  302  may display information from system  300  through the application. In another example, a digital wallet that securely stores financial payment information on mobile device  302  may be used to purchase additional credits, order products (e.g., food and drinks) and/or services, and the like through the application. In other embodiments, the mobile device  302  accesses a web interface to provide the features described herein. In addition to the new features provided by integration of the mobile device  302  with the system  300 , the system  300  may harness the processing, memory, and/or network capabilities of the mobile device  302  to perform various tasks, thereby reducing the computing resource burden on the system  300 . 
     In the example embodiment, the system  300  communicates with the mobile device  302  to authenticate or verify the identity of the player  301 , the mobile device  302 , and/or a player account of the player  301  for player tracking. The player account may be stored by game network  360 . The player account may include, for example, game play data (e.g., scores, game play progress, etc.), credit balance data, and other data associated with the player  301 , including data unrelated to game play. For example, the player account may include a list of historical purchases made by the player  301 , such as drink purchases, and/or timestamps associated with different events involving the player  301  (e.g., the last time the player  301  visited the casino). When the system  300  verifies the identity of the player  301 , the mobile device  302 , and/or the player account, data from the player account is provided to the gaming machine  310  for a gaming session as described herein. Additionally or alternatively, the mobile device  302  may be used to verify the presence of the player  301  at the gaming machine  310  during the gaming session to facilitate improved accuracy and speed detecting abandoned gaming sessions and absent players. Detecting abandoned gaming sessions at the machine  310  may enable the gaming machine  310  to end the abandoned gaming session automatically and become available for a new gaming session with a new player. 
     The acoustic interface  320  is configured to facilitate establishing and/or maintaining a gaming session. In particular, the acoustic interface  320  operates in conjunction with a corresponding acoustic interface of the mobile device  302  to transmit and/or receive acoustic signals. The acoustic signals are configured to transmit data between the gaming machine  310  and the mobile device  302 . That is, the acoustic signals have distinctive characteristics that are encoded with data. When signal analysis is performed on the acoustic signals, the encoded data may be extracted or otherwise determined. In one example, the acoustic signals are modulated to form a bit stream. The receiver of the modulated acoustic signal demodulates the signal to collect the bit stream. 
     Unlike other forms of communication between computing devices, such as near field communication (NFC), Bluetooth, Wi-Fi, cellular communication, and the like, acoustic interfaces, such as the interface  320 , are adopted by a majority (if not all) mobile devices. The prevalence of acoustic interfaces reduces the barrier of entry for players to use this feature. In addition, in at least some embodiments, the gaming machine  310  may include one or more metal components that may attenuate radio signals, impact triangulation of signals to the correct gaming machine  310 , or otherwise negatively impact communication with the gaming machine  310  using digital communication rather than acoustic communication. Moreover, adding acoustic interfaces to a gaming machine or mobile device may be a relatively inexpensive process unlike the components of at least some of the aforementioned forms of communication. In at least some embodiments, the features described herein may be relatively quick to use and are at least partially automated to reduce the burden on the player  301  (i.e., the features are “tap-and-go” features). 
     In the example embodiment, the acoustic interface  320  is integrated with the gaming machine  310 . In other embodiments, the acoustic interface  320  may be at least partially located remotely from the gaming machine  310 . In such embodiments, the acoustic interface  320  is communicatively coupled to the logic circuitry  340 . As shown in  FIG. 3 , the acoustic interface  320  includes an acoustic input component  322  and an acoustic output component  324 . In at least some embodiments, acoustic interface  320  includes additional, fewer, or alternative components, including those described elsewhere herein. For example, the acoustic interface  320  may include only one of the input component  322  or the output component  324 . In another example, the acoustic interface  320  includes a plurality of input components  322  and/or output components  324 . In yet another example, the acoustic interface  320  includes a device interface (not shown in  FIG. 3 ) to support mobile devices as described herein. In the example embodiment, the acoustic interface  320  of the gaming machine  310  is configured for at least unidirectional communication with corresponding acoustic components of the mobile device  302 . That is, the acoustic interface  320  is configured to receive acoustic signals from the mobile device  302  (e.g., via the acoustic input component  322 ), and/or is configured to transmit acoustic signals to the mobile device  302  (e.g., via the acoustic output component  324 ). 
     The acoustic input component  322  is configured to receive acoustic signals. In some embodiments, the input component  322  may also process the acoustic signals, such as filtering noise from the signal and/or converting the analog acoustic signals to corresponding digital signals. In the example embodiment, the input component  322  is a microphone. The input component  322  may include additional devices and/or circuits to process the received acoustic signals, such as analog to digital converters, filter circuits, and microprocessors. In certain embodiments, processing the acoustic signals may be at least partially performed by the logic circuitry  340 . 
     The acoustic output component  324  is configured to emit acoustic signals. The acoustic signals may include, but are not limited to, game play sounds, notification sounds, and/or acoustic signals embedded with data as described herein. In the example embodiment, the acoustic output component  324  is a speaker or a plurality of speakers. In at least some embodiments, the output component  324  may include other devices and/or circuits to generate and/or emit the acoustic signals, such as digital to analog converters, modulation circuits, and the like. In at least some embodiments, the logic circuitry  340  is configured to transmit the acoustic signal to the output component  324  for emission of the signal. 
     In the example embodiment, the acoustic interface  320  is configured to be selectively activated and deactivated by logic circuitry  340 . That is, the acoustic interface  320  receives and/or emits acoustic signals when activated, and the acoustic interface  320  does not receive and/or emit acoustic signals when deactivated. In some embodiments, the acoustic input component  322  and the acoustic output component  324  are separately activated and deactivated. Selectively activating the acoustic interface  320  enables resources of logic circuitry  340  to be allocated to other tasks and components and limits miscommunication intended for the mobile device  302  as described herein. 
     The presence sensor  330  is configured to detect the presence of players and/or mobile devices near the gaming machine  310 . In particular, in the example embodiment, the presence sensor  330  is configured to detect a mobile device and/or a player to cause the logic circuitry  340  to selectively enable the acoustic interface  320  in response to detecting a nearby mobile device or player. Although the sensor  330  is described herein as a single sensor, it is to be understood that gaming machine  310  may include multiple sensors  330  having different or similar types, configurations, and the like. The presence sensor  330  is coupled to the cabinet of the gaming machine  310  in a suitable configuration to detect the player  301  and/or the mobile device  302 . The presence sensor  330  is communicatively coupled to the logic circuitry  340  to notify the logic circuitry  340  of the presence of the player  301  at the gaming machine  310 . More specifically, the presence sensor  330  collects sensor data and transmits the sensor data to the logic circuitry  340  for analysis. The presence of the player  301  may be used, for example, to determine if the player  301  is approaching the gaming machine  310  to begin a gaming session and/or to determine if the player  301  has left the gaming machine  310  during an in-progress gaming session. 
     The presence sensor  330  is configured to detect the player  301  and/or the mobile device  302  within a detection range. The detection range may be, for example, a suitable distance range in which the sensor  330  is configured to collect sensor data, or the detection range may be an effective communication range of the sensor  330 . As used herein, a “communication range” refers to a distance defined by the signal characteristics of signals communicated between two devices. Although signal communication may be possible outside of the communication range, the signals may be increasingly susceptible to noise degradation and other factors that cause the communication to become unreliable as the distance between the devices is extended beyond the communication range. In some embodiments, the presence sensor  330  is a proximity sensor for detecting the player  301  or the mobile device  302 . For example, the presence sensor  330  may be a time-of-flight laser sensor configured to detect the mobile device  302  approaching the gaming machine  310 . In certain embodiments, when the sensor  330  detects the player  301  or the mobile device  302 , the logic circuitry  340  or the sensor  330  may classify the movement of the detected object to determine if the player  301  is approaching the gaming machine  310 , proximate the gaming machine  310 , or passing by the gaming machine  310 . The logic circuitry  340  may cause different processes to be performed based on the classified movement. 
     In some embodiments, the presence sensor  330  may be a communication beacon that communicates with the mobile device  302  to detect the presence of the player  301 . For example, the presence sensor  330  may be a Bluetooth, Bluetooth Low Energy (BLE), Wi-Fi, and/or NFC beacon that detects the mobile device  302 . In such embodiments, the presence sensor  330  may transmit and/or receive data from the mobile device  302 . In certain embodiments, the presence sensor  330  and/or the audio interface  320  may be used to determine the location of players within a casino or other gaming establishment. That is, the presence sensor  330  and/or the audio interface  320  may be configured to determine how far away a player (or mobile device) is from the gaming machine  310 . By analyzing the distances determined by multiple gaming machines, an approximate location of the player may be identified. 
     In the example embodiment, the gaming system  300  is configured to perform three processes for managing a gaming session—(i) establish a gaming session, (ii) maintain a gaming session, and (iii) end a gaming session. In particular, the acoustic interface  320  is configured to communicate with the mobile device  302  to establish the gaming session during a session-establishment process and to maintain the gaming session during a maintain-session process. When communication is interrupted, that association between the player account of the player  301  and the gaming session is terminated, or, in some cases, temporarily suspended. Concurrent to or subsequent to terminating the association between the player account and the gaming session, the gaming session is terminated during an end-session process, thereby freeing the gaming machine  310  for a subsequent gaming session. Moreover, the processes described herein enable pairing or linking the mobile device  302  to the gaming session, thereby providing additional features to the player  301  via the mobile device  302 . For example, when the mobile device  302  is paired to the gaming session, player account information may be displayed on the mobile device  302 . In another example, a digital wallet stored on the mobile device  302  may be used to purchase credits, products (e.g., drinks), and/or services provided by the game network  360 . 
     The acoustic interface  320  is configured to communicate with the mobile device  302  using acoustic signals embedded with data. The acoustic signals have particular characteristics (e.g., amplitude, phase, frequency, modulation, etc.) that represent digital data. The logic circuitry  340  and/or the mobile device  302  may be configured to perform signal analysis on the acoustic signals to extract the data. The acoustic interface  320  and/or the mobile device  302  may include circuitry and/or devices configured to facilitate embedding and extracting the data from the acoustic signals. Although the example embodiment describes the acoustic input component  322  receiving acoustic signals from an acoustic output component (e.g., speaker) of the mobile device  302 , it is to be understood that the acoustic output component  324  may be used to generate and emit the acoustic signals to be received by an acoustic input component (e.g., microphone) of the mobile device  302  in addition to or alternative to the input component  322  receiving acoustic signals. That is, the acoustic data transmission described herein may be unidirectional or bidirectional. 
       FIG. 4  is a data flow diagram of an example session-establishment process performed by the gaming system  300  shown in  FIG. 3 .  FIG. 5  is a flow diagram of the session-establishment process  500  shown in  FIG. 4 . In other embodiments, the process  500  may include additional, fewer, or alternative data elements and/or steps, including those described elsewhere herein. 
     In the example embodiment, the player  301  activates the application installed on his or her mobile device  302  (or accesses a web interface associated with the system  300 ) when the player  301  wants to begin a gaming session on gaming machine  310 . Among other options presented to the player  301 , the application provides the player an option to initiate the process  500 . In particular, when the player  301  selects the option to initiate the process  500 , the mobile device  302  is configured to emit a capture signal  402 . The capture signal  402  is an acoustic signal having specific characteristics (e.g., frequency, phase, amplitude, modulation, etc.) that enable embedding data, such as binary computer data, within the capture signal  402 . In the example embodiment, the mobile device  302  performs one or more modulation schemes or methods to embed data with the capture signal  402 . That is, the mobile device  302  performs frequency-based modulation, amplitude-based modulation, phase-based modulation, or combinations thereof to embed the data such that a corresponding device-receiving the signal (e.g., the gaming machine  310 ) can extract the data using acoustic signal analysis techniques. Examples of modulation schemes include continuous wave modulation schemes, analog modulation schemes, and digital modulation schemes, such as frequency-shift keying (FSK), phase-shift keying (PSK), and amplitude-shift keying (ASK). In some embodiments, the mobile device  302  does not generate the capture signal  402 , but rather, for example, receives the modulated capture signal  402  from the gaming machine  310  or the game network  360 . 
     In the example embodiment, the capture signal  402  is representative of a player account identifier  404 . The player account identifier  404  is associated with a player account  406  of the player  301  and may be stored by the game network  360 . The player account  406  includes information associated with the player  301 , such as, and without limitation, historical game play data, order data (e.g., food and drinks ordered by the player  301 ), credit balance data, player data, and the like. In at least some embodiments, the player account identifier  404  is embedded in the capture signal  402 . In other embodiments, representative data associated with the player account identifier  404  is embedded in the capture signal  402  in place of the player account identifier  404 . For example, the representative data may be an encryption key associated with the player account identifier  404  and/or an encrypted player account identifier  404 . In another example, the data may be a portion of the player account identifier  404 . Additionally, the capture signal  402  may include supplemental data  408  with the player account identifier  404  or the representative data. The supplemental data  408  may be used to authenticate the capture signal  402 , provide details regarding an available communication channel provided by the mobile, and/or other suitable information. In one example, the supplemental data  408  includes a timestamp to prevent fraudulent parties from recording a previous capture signal  402  for fraudulent use. In another example, the supplemental data  408  may provide information to facilitate establishing Bluetooth or Wi-Fi communications with the mobile device  302 . In yet another example, the supplemental data  408  includes a pre-shared encryption key, a pairing key for communications, a server internet protocol (IP) address, a universal resource locator (URL) associated with the system  300  or the mobile device  302 , and/or the like. In other embodiments, the capture signal  402  is not embedded with the player account identifier  404  or the representative data. Rather, in such embodiments, a different identifier is used to retrieve the correct player account  406  and/or to establish communications between the mobile device  302  and the gaming system  300 . 
     When the capture signal  402  is generated, the application installed on the mobile device  302  causes the acoustic output component of the mobile device  302  to emit the capture signal  402 . In at least some embodiments, the capture signal  402  is emitted inaudibly. That is, human acoustic systems are unable to detect the frequencies and the amplitude of the capture signal  402 . The frequency range of audible tones is approximately between 20 Hertz (Hz) and 20 kHz. Inaudible tones have frequencies outside of this range. In one example, the capture signal  402  is an ultrasonic acoustic signal (i.e., greater than 20 kHz). In other embodiments, at least a portion of the capture signal  402  may be an audible tone. To avoid cross-communication with other mobile devices  302  and/or gaming machines  310  and noise degradation, the capture signal  402  may have a limited communication range (e.g., approximately 5-40 centimeters). For example, the amplitude (i.e., the loudness) of the capture signal  402  may be relatively low to reduce the effective communication range of the capture signal  402 . 
     In the example embodiment, when the capture signal  402  is emitted, the application causes the mobile device  302  to display instructions to the player  301  regarding where to position the mobile device  302  relative to the gaming machine  310  to accommodate the limited communication range of the capture signal  402 . The gaming machine  310  may also include instructions, graphics, and the like that indicate where the mobile device  302  should be positioned. When the player  301  approaches the gaming machine  310 , the presence sensor  330  detects the player  301  and/or the mobile device  302 . In some embodiments, the presence sensor  330  automatically detects the player  301  and/or the mobile device  302  (e.g., the presence sensor  330  detects the proximity of objects within its detection range). In other embodiments, the player  301  or the mobile device  302  may initiate contact with the presence sensor  330  (e.g., the mobile device communicatively couples to the sensor  330  via BLE). 
     In response to the detection, the logic circuitry  340  is configured to activate the acoustic input component  322  to receive  502  the capture signal  402  from the mobile device  302 . Prior to activation, the acoustic input component  322  is inactive to limit cross-communication and errors caused by noise. When the acoustic input component  322  receives  502  the capture signal  402 , the signal  402  is converted from an analog acoustic signal to a digital signal for analysis by the logic circuitry  340 . The logic circuitry  340  is configured to perform acoustic signal analysis on the capture signal  402  to determine  504  the player account identifier  404 . For example, if the player account identifier  404  is embedded in the capture signal  402 , the logic circuitry  340  is configured to extract the player account identifier  404 . In some embodiments, the gaming machine  310  transmits the capture signal  402  to the game network  360  for analysis. In such embodiments, the game network  360  is configured to determine the player account identifier  404  from the capture signal  402 . 
     In the example embodiment, the gaming machine  310  retrieves  506  account data  410  associated with the player account  406  from the game network  360 . In particular, the gaming machine  310  queries the game network  360  using the player account identifier  404 . The game network  360  performs a lookup of stored player accounts using the player account identifier  404  and retrieves the account data  410 . The account data  410  may include, for example, historical game play data, order data, and/or other information from the player account  406 . In some embodiments, a credit balance associated with the player  301  may be established based on the account data  410 . That is, credits may be transferred from the player account  406  to the gaming machine  310  for the gaming session. In such embodiments, when the gaming session is ended, the remaining credit balance at the gaming machine  310  may be transferred back to the player account  406  for subsequent play. 
     When the account data  410  is retrieved  506 , the gaming machine  310  establishes  508  a gaming session associated with the player account  406 . In the example embodiment, during or after the gaming session, the logic circuitry  340  transmits  510  game play information  412  related to the gaming session to the player account  406  on the game network  360 . The game play information  412  includes information associated with the current gaming session, such as, and without limitation, game play results, winning outcomes, current credit balance, wagers placed, and the like. The gaming play information  412  is collected and/or generated by the logic circuitry  340  during the gaming session. The game play information  412  may be transmitted  510  periodically (e.g., at the end of each play of the game) or asynchronously. For example, the game play information  412  may be transmitted  510  at the conclusion of the gaming session. The player account  406  is updated with the game play information  412  such that account data  410  retrieved for subsequent gaming sessions may incorporate at least a portion of the game play information  412 . 
     In certain embodiments, the mobile device  302  and the game network  360  communicate with each other during the session-establishment process  500 . In one example, to initiate the process  500 , the mobile device  302  transmits an activation signal  414  to the game network  360 . The activation signal  414  is a digital signal indicating that the mobile device  302  is emitting the capture signal  402 . In some embodiments, the activation signal  414  includes the player account identifier  404  and/or location data associated with the mobile device  302 . The player account identifier  404  may be used to authenticate the player  301 . That is, the player account identifier  404  from the capture signal  402  is compared to the player account identifier included with the activation signal  414  to verify that the authentic player  301  is establishing the gaming session. If the activation signal  414  includes location data (e.g., Global Positioning System (GPS) data), the game network  360  may notify gaming machines  310  proximate to the player  301  to activate their corresponding acoustic input components  322 . In other embodiments, the activation signal  414  is an audio signal emitted by the mobile device  302  or the gaming machine  310 . In such embodiments, the activation signal  414  may be embedded with preliminary data to identify the mobile device  302  or the gaming machine  310 . In response to receiving the activation signal, the mobile device  302  or the gaming machine  310  may activate their corresponding audio interface to initiate the session-establishment process  500 . 
     During the gaming session, the mobile device  302  may receive at least a portion of the account data  410  and/or the game play information  412  from at least one of the gaming machine  310  or the game network  360 . For example, the mobile device  302  may display secondary content (e.g. player tracking information, supplemental game content, etc.) for the gaming session to player  301  based at least partially upon the account data  410  and/or the game play information  412 . In some embodiments, the mobile device  302  transmits app data  416  to the gaming machine  310  and/or the game network  360  during the gaming session. The app data  416  includes user input, payment information, device information, and other information stored or collected by the mobile device for the gaming session. For example, the app data  416  may include user input for placing a wager for the wagering game or payment information from a digital wallet stored on the mobile device  302  to complete transactions, such as transaction to purchase additional credits, drinks, food, and the like. The app data  416  may be transmitted periodically or asynchronously to the gaming machine  310  and/or the game network  360 . 
     In at least some embodiments, the acoustic interface  320  (shown in  FIG. 3 ) includes a device interface on the cabinet of the gaming machine  310  to facilitate communication between the mobile device  302  and the gaming machine  310  during the session-establishment process  500 . In particular, due to the limited communication range of the capture signal  402 , the device interface is positioned near the acoustic input component  322  such that the device interface is within the communication range of the capture signal  402 . In certain embodiments, the device interface is configured to receive the mobile device and direct acoustic signals from the mobile device  302  to the acoustic input component  322 . Similarly, if the capture signal  402  is transmitted by the acoustic output component  324  to the mobile device, the device interface directs the capture signal  402  towards the mobile device  302 . 
       FIG. 6  is a perspective view of an example device interface  600  for use with the gaming system  300  (shown in  FIG. 3 ). In the example embodiment, interface  600  is positioned near an acoustic input component  622  and one or more value input and/or output devices. Interface  600  includes an instruction graphic  602  and a device-receiving component  604 . In other embodiments, interface  600  includes additional, fewer, or alternative components, including those described elsewhere herein. For example, interface  600  may not include the instruction graphic  602 . 
     The instruction graphic  602  is positioned near the receiving component  604  to visually prompt the player  301  (shown in  FIG. 3 ) where to place his or her mobile device  302 . The graphic  602  may be, for example, a sticker, a painted image, a placard, a graphical display, and/or other visual indicators. The graphic  602  may include a set of instructions, an image of a mobile device, and/or other visual instructions. In certain embodiments, the graphic  602  is paired with instructions displayed on the mobile device  302  to prompt the player  301  to position the mobile device  302  properly in the interface  600 . In the example embodiment, the mobile device  302  may be horizontally oriented (as shown in  FIG. 6 ) or vertically oriented relative to the interface  600  to facilitate the functions described herein. 
     The device-receiving component  604  is configured to receive the mobile device  302  and direct acoustic signals between the mobile device  302  and the acoustic input component  622 .  FIG. 7  is a perspective view of the device-receiving component  604 . With respect to  FIGS. 6 and 7 , the receiving component  604  includes a base member  606  that extends between two side members  608 . In the example embodiment, the side members  608  extend substantially perpendicular to the base member  606 . The base member  606  includes a receiving surface  610  for receiving the mobile device  302 . The receiving surface  610  is configured to receive the mobile device  302  vertically or horizontally. In the example embodiment, the base member  606  is not flat. That is, the base member  606  is curved to form a concave receiving surface  610 . Mobile devices typically have substantially flat edges, and thus a gap may be formed between a portion of the mobile device  302  and the receiving surface  610 . The gap is configured to direct acoustic sound waves between the acoustic interfaces of the mobile device  302  and the acoustic input component  622 . In other embodiments, the base member  606  is curved to form a convex receiving surface  610 . Alternatively, the base member  606  may be substantially flat relative to the side members  608 . 
     In the example embodiment, the receiving component  606  does not include supports for securing the mobile device  302  to the interface  600  because the relatively short amount of time required to transmit the capture signal  402  does not require the mobile device  302  to be positioned on the interface  600  for extended periods of time. After the capture signal  402  is transmitted and received, the mobile device  302  does not need to stay within the communication range defined by the capture signal  402 , thereby enabling the player  301  to use and move the mobile device  302  without further consideration of the interface  600 . In other embodiments, the receiving component  606  includes one or more supporting members (not shown) to secure the mobile device  302 . In such embodiments, the mobile device  302  and the gaming machine  310  may continue to communicate with each other using acoustic signals. For example, acoustic signals may be transmitted by the mobile device  302  to the gaming machine  310  to maintain the gaming session as described herein. 
       FIG. 8  is a data flow diagram of an example maintain-session process performed by the gaming system  300  shown in  FIG. 3 .  FIG. 9  is a flow diagram of the maintain-session process  900  shown in  FIG. 8 . In other embodiments, the process  900  may include additional, fewer, or alternative data elements and/or steps, including those described elsewhere herein. 
     When a gaming session is established at the gaming machine  310 , the logic circuitry  340  or the mobile device  302  determines  902  a session identifier  802  associated with the gaming session. In the example embodiment, the session identifier  802  is a unique identifier received by the gaming machine  310  and the mobile device  302  from the game network  360  to verify the identity and presence of the mobile device  302  during the gaming session. For example, the session identifier  802  may be a player account identifier (e.g., player account identifier  404 , shown in  FIG. 4 ), a device identification number (e.g., of the mobile device  302  or the gaming machine  310 ), a phone number, a randomly-generated alphanumeric identifier, and the like. In certain embodiments, the session identifier  802  is an acoustic signature associated with the mobile device  302  and/or the gaming machine  310 . That is, in such embodiments, the session identifier  802  is an acoustic signal with a set of characteristics that identify the mobile device  302  and/or the gaming machine  310 . In one example, the session identifier  802  is an unmodulated audio tone, such as an audio pulse, that is associated with the gaming session. In some embodiments, the session identifier  802  may be generated by the mobile device  302  or the gaming machine  310  and transmitted to the other device for storage and subsequent use. The session identifier  802  may be static or dynamic. For example, the identifier  802  may be updated periodically, at the beginning of a gaming session, and/or at the end of the gaming session. 
     The session identifier  802  is stored by the logic circuitry  340  and linked to the gaming session of the player  301 . The session identifier  802  is also stored by the mobile device  302  for the maintain-session process  900 . In some embodiments, the session identifier  802  may be generated and/or assigned by the game network  360  to the mobile device  302  and the gaming machine  310 . In one example, the logic circuitry  340  transmits the session identifier  802  to the game network  360  for subsequent transmittal to the mobile device  302 . In another example, the game network  360  retrieves the session identifier  802  from the player account  406  (shown in  FIG. 4 ) associated with the player  301 . 
     In the example embodiment, to maintain the gaming session of the player  301 , the mobile device  302  is configured to generate and emit a maintain-session signal  804 . The maintain-session signal  804  is an acoustic signal having unique maintain-session characteristics that represent the session identifier  802 . That is, the maintain-session characteristics of the signal  804  form a bit stream including embedded data representing the session identifier  802 . The embedded data, similar to the embedded data within the capture signal  402  (shown in  FIG. 4 ), may include, but is not limited to, at least a portion of the session identifier  802 , encrypted data representing the identifier  802 , an encryption key associated with the identifier  802 , and/or another abstraction of the session identifier  802 . In addition, in some embodiments, the embedded data includes supplemental data  806  to provide various features. For example, the supplemental data  806  may include a timestamp or time code to verify the maintain-session signal  804  as authentic rather than a prerecorded maintain-session signal. The embedded data may be encrypted to limit fraudulent parties from intercepting the maintain-session signal  804 . In certain embodiments, the maintain-session signal  804  does not include data, but rather includes audio characteristics that, when analyzed, verify the presence of the mobile device  302 . For example, the maintain-session signal  804  may be an unmodulated signal with an audio tone representing the session identifier  802 . In other embodiments, the maintain-session signal  804  is received by the mobile device  302  from the gaming machine  310  and/or the game network  360 . In one embodiment, the gaming machine  310  generates and emits the maintain-session signal  804  (e.g., via the acoustic output component  324 , shown in  FIG. 3 ) to the mobile device  302 . The mobile device  302  then stores the signal  804  for subsequent use. 
     The maintain-session signal  804  may include audible and/or inaudible (e.g., ultrasonic) tones similar to the capture signal  402 . In one embodiment, the maintain-session signal  804  has a frequency range approximately at 18 kHz. In the example embodiment, the maintain-session signal  804  has acoustic characteristics that cause the signal  804  to be substantially imperceptible to the human auditory system when emitted by the mobile device. In other embodiments, the signal  804  is perceptible to the human auditory system. In certain embodiments, the maintain-session signal  804  may have variable acoustic characteristics, thereby enabling the mobile device  302  to vary the emission of the signal  804 . For example, the signal  804  may initially be imperceptible to the human auditory system and gradually become perceptible if there is no confirmation that the signal  804  was received. In one example, to calibrate the maintain-session signal  804 , the maintain-session signal  804  may be emitted at varying amplitudes, frequencies, and/or phases to determine a communication range, the quality of communication, and other factors that may be adjusted in response to calibration. 
     Similar to the capture signal  402 , the maintain-session signal  804  has a limited communication range to prevent cross-communication and noise degradation. In the example embodiment, the communication range of the maintain-session signal  804  is greater than the communication range of the capture signal  402  to enable the player  301  to move and use the mobile device  302  throughout the gaming session. For example, the communication range of the maintain-session signal  804  may be between 50 cm and 500 cm while the communication range of the capture signal  402  is between 10 cm and 30 cm. 
     The logic circuitry  340  receives  904  the maintain-session signal  804  emitted by the mobile device  302  in a prescribed manner via the acoustic input component  322 . The logic circuitry  340  then extracts the embedded data from the signal  804  using acoustic signal analysis and determines  806  the session identifier  802  from the extracted data. In certain embodiments, if the session identifier  802  is not previously known by the logic circuitry  340 , the logic circuitry  340  links the session identifier  802  to the gaming session and stores the identifier  802  for comparison to the session identifiers of subsequent maintain-session signals. If the session identifier  802  has been previously stored by the gaming machine  310  (or the game network  360 ), the determined session identifier  802  is compared to the previously stored session identifier  802 . If the two session identifiers substantially match, the logic circuitry  340  assumes the player  301  is still present at the gaming machine  310  and maintains  906  the gaming session (and the association between the gaming session and the player account  406  (shown in  FIG. 4 ) of the player  301 ). If the comparison does not result in a substantial match, the comparison may indicate that the player  301  has left the gaming machine  310 . 
     When the logic circuitry  340  fails to receive the maintain-session signal  804  according to the prescribed manner, the logic circuitry  340  terminates  908  the association between the gaming session and the player account  406 . In some embodiments, terminating  908  the association also automatically terminates the gaming session. In other embodiments, the gaming session continues without being associated to the player account  406 . In some embodiments, the logic circuitry  340  may terminate the association between the player account  406  and the gaming session if the logic circuitry  340  receives, via the acoustic input component  322 , a maintain-session signal that includes a session identifier associated with a mobile device other than the mobile device  302  of the player  301 . The signal with the new session identifier may indicate that the player  301  has left the gaming machine  310  and a new player is present at the gaming machine. In such embodiments, the logic circuitry  340  may automatically terminate the gaming session of the player  301  and initiate a session-establishment process (e.g., the process  500 , shown in  FIG. 5 ) for the new player. In certain embodiments, the logic circuitry  340  may communicate the session identifier associated with the new player to the game network  360  and/or other gaming machines. If the new player is associated with a current gaming session at another gaming machine, the other gaming machine may automatically end the gaming session of the new player. 
     In the example embodiment, the prescribed manner defined by the process  800  includes receiving  904  the maintain-session signal  804  periodically to continue to maintain  906  the gaming session. In particular, the logic circuitry  340  stores a time schedule  808  that defines the frequency at which the maintain-session signal  804  is expected from the mobile device  302 . The frequency may be, for example, and without limitation, every 10 seconds, 30 seconds, 1 minute, or 3 minutes. The frequency may be variable based on one or more timing criteria. The timing criteria may indicate activity by the player  301  and/or the mobile device  302  beyond the maintain-session signal  804 , such as the last received user input at the gaming machine  310 , activity on a communication channel between the gaming machine  310  and the mobile, detection of the player  301  using the presence sensor  330  (shown in  FIG. 3 ). 
     The time schedule  808  includes a presence counter  810  associated with the gaming session. The presence counter  810  is initiated in response to one or more trigger events. The trigger events may include, but are not limited to, receiving a maintain-session signal  804 , failing to receive the signal  804  at a predetermined time according to the time schedule  808 , failing to detect the player  301  with the presence sensor  330 , or terminating a communication channel between the mobile device  302  and the gaming machine  310 . The presence counter  810  is incremented or decremented over time and compared to a predetermined presence threshold value  812 . The initial value of the presence counter  810  or the threshold value  812  may be variable to vary based on the timing criteria. The logic circuitry  340  determines whether or not the player  301  is still present based on the comparison. In one example, the presence threshold value  812  is zero, and the presence counter  810  is decremented over time. When the presence counter  810  reaches zero, an end-session process is initiated to terminate the gaming session. In certain embodiments, the logic circuitry  340  may notify the player  301  that when the counter  910  is approaching the threshold value  812  and no maintain-session signal  804  has been received. The logic circuitry  340  resets the presence counter  810  each time the maintain-session signal  804  is received  904  from the mobile device  302 . In some embodiments, when the presence counter  810  is reset, the logic circuitry  340  determines whether or not to modify the initial value of the presence counter  810  or the threshold value  812  based on the timing criteria. 
     In certain embodiments, the logic circuitry  340  is configured to determine a distance between the gaming machine  310  and the player  301  and/or the mobile device  302 . If the distance exceeds a predetermined maximum distance  814  stored in memory by the logic circuitry  340 , the logic circuitry  340  may determine that the player  301  has abandoned the gaming session. In response, the logic circuitry  340  terminates the association between the gaming session and the player account  406  and/or terminates the gaming session altogether. In at least some embodiments, the presence sensor  330  is configured to determine the distance between the player  301  (or the mobile device  302 ) and the gaming machine  310 . In one example, the presence sensor  330  may not determine the specific distance, but rather defines the predetermined maximum distance  814  by its detection range such that players and mobile devices detected within the detection range are not outside of the predetermined maximum di stance  814 . 
       FIG. 10  is a flowchart diagram of an example end session process  1000  performed by the gaming system  300  (shown in  FIG. 3 ). In particular, the process  1000  is performed at least partially by the logic circuitry  340  (shown in  FIG. 3 ). That is, the logic circuitry  340  stores one or more instructions that, when executed, cause the logic circuitry  340  to perform one or more steps of the process  1000 . In some embodiments, the process  1000  may be at least partially performed by a different device or system, such as the game network  360  (shown in  FIG. 3 ). In other embodiments, the process  1000  includes additional, fewer, or alternative steps, including those described elsewhere herein. 
     With respect to  FIGS. 3 and 10 , when the player is determined to be inactive or absent from the gaming machine  310  for a period of time (e.g., failure to receive the maintain-session signal  804 , shown in  FIG. 8 ), the logic circuitry  340  analyzes  1002  one or more end-session criteria associated with the gaming session. The end-session criteria is information that may be indicative of the likelihood that the player  301  will continue the gaming session (i.e., the player  301  interrupts the process  1000 ). For example, if the player  301  has a credit balance with remaining credits, the player  301  is more likely to continue the gaming session than if the player  301  has no remaining credits. In another example, the logic circuitry  340  determines whether or not the mobile device  302  and the gaming machine  310  are communicatively coupled to each other via one or more communication channels, such as BLE, Bluetooth, NFC, Wi-Fi, etc. That is, if the mobile device  302  and the gaming machine  310  are communicatively coupled to each other, the mobile device  302  and the player  301  are located within a distance of the gaming machine  310  defined by the communication channel, and thus may be returning to the gaming machine  310 . 
     In at least some embodiments, the analysis of the end-session criteria may result in the player  301  and/or the logic circuitry  340  terminating the process  1000  to continue the gaming session. More specifically, the gaming machine  310  or the mobile device  302  may display a notification to the player  301  indicating the gaming session is ending. The player  301  may provide user input to indicate whether or not the player  301  wants to continue the gaming session. Additionally or alternatively, the logic circuitry  340  automatically continues the gaming session based on the analysis of the end-session criteria. In one example, the end-session criteria indicates that the presence sensors  330  detects the player  301  and the mobile device  302  is in communication with the gaming machine  310  via BLE. If the process  1000  was preceded by a maintain-session process using acoustic signals (e.g., the process  900 , shown in  FIG. 9 ), the end-session criteria in this example may indicate that acoustic communication between the mobile device  302  and acoustic interface  320  is blocked, which may be caused by the mobile device  302  being placed in a pocket, purse, or bag of the player  301  during the gaming session. In this example, the mobile device  302  or the gaming machine  310  provides a visible, audible, and/or tactile (e.g., vibration) notification to the player  301  to prompt the player  301  position the mobile device  302  in a suitable location for the maintain-session process. 
     In the example embodiment, based on the analysis of the end-session criteria, the logic circuitry  340  establishes  1004  an end-session counter and an end-session threshold value. The end-session counter and/or the end-session threshold value are variable based on the analysis of the end-session criteria to provide more time to players more likely to continue the gaming session and less time to players less likely to continue the gaming session. Extending the time provided to players more likely to continue the gaming session facilitates reducing the amount of prematurely ended gaming sessions that may discourage the players from subsequent play. Decreasing the time provided to players less likely to continue the gaming session facilitates increased availability of the gaming machine  310  to new players, thereby decreasing down time between gaming sessions. 
     The end-session counter is incremented or decremented over time and is periodically compared  1006  to the end-session threshold by the logic circuitry  340 . When an end-session event (e.g., the value of the end-session counter is equal to the end-session threshold value) is detected based on the comparison, the logic circuitry  340  transmits  1008  the game play information  412  associated with the gaming session to the player account  406  (shown in  FIG. 4 ) of the player  301 . For example, if there are remaining credits, the credits are applied to the player account  406  or are otherwise refunded to the player  301 . In another example, game play progress during the gaming session is stored with the player account  406  to enable subsequent play without loss the progress. In some embodiments, the association between the player account  406  and the gaming session is terminated prior to the process  1000 , such as by the maintain session process  900  shown in  FIG. 9 . In such embodiments, the transmitting  1008  step may not be performed, although remaining credits may still be refunded to the player  301 . Afterwards, the logic circuitry  340  terminates  1010  the gaming session associated with the player  301  to enable other players to establish new gaming sessions at the gaming machine  310 . 
     With reference to  FIGS. 3, 5, 9, and 10 , the session-establishment process  500 , the maintain-session process  900 , and the end-session process  1000  may be performed by system  300  separately or in combination with each other. For example, in some embodiments, the system  300  may only perform the session-establishment process  500  while using other processes and techniques for maintaining and ending the gaming session. In at least some embodiments, when the session-establishment process  500  and the maintain-session process  900  are performed by the gaming system  300 , the logic circuitry  340  is configured to distinguish between capture signals and maintain-session signals to prevent cross-communication with other mobile devices and gaming machines. In particular, the capture signals and the maintain-session signals have distinctive acoustic characteristics that enable the logic circuitry  340  to distinguish between the two signal types using signal analysis and/or acoustic filters. For example, the capture signals and the maintain-session signals may use different frequency bands (frequency ranges) to transmit the embedded data. In one example, the capture signals are emitted at frequencies and amplitudes that facilitate higher data bandwidth over shorter ranges relative to the frequencies and amplitudes of the maintain-session signals which may have a relatively low data bandwidth and a relatively larger communication range. In some embodiments, the capture signals and the maintain-session signals use different modulation schemes to transmit the embedded data. In one example, the capture signals use phase-based modulation while the maintain-session signals use frequency-based modulation. In this example, the logic circuitry  340  decodes or demodulates a received acoustic signal based on the expected type of signal depending on which process is being performed. In certain embodiments, the capture signals and/or the maintain-session signals include embedded data that identify the type of acoustic signal (e.g., supplemental data  408  and  806 , shown in  FIGS. 4 and 8 , respectively). 
     In some embodiments, the directionality of the acoustic communication between the mobile device  302  and the gaming machine  310  may be different for the session-establishment process  500  and the maintain-session process  900 . In one example, the session-establishment process  500  involves the capture signal  402  (shown in  FIG. 4 ) being received by the acoustic input component  322  from the mobile device while the maintain-session process  900  involves the acoustic output component  324  emitting the maintain-session signal  804  (shown in  FIG. 8 ) to be received by the mobile device. In another example, the session-establishment process  500  involves unidirectional communication via acoustic signals while the maintain-session process  900  involves bidirectional communication, thereby facilitating data transmission back and forth between the mobile device  302  and the gaming machine  310  during the gaming session. 
     The foregoing gaming systems and methods facilitate establishing, maintaining, and terminating a gaming session associated with a player account on a gaming machine using acoustic signatures communicated between the gaming machine and a mobile device of the player. Moreover, the foregoing gaming systems and methods facilitate linking or pairing the mobile device to the gaming session to provide additional features to the player via the mobile device. The use of acoustics rather than other forms of communication (BLE, NEC, etc.) facilitates increased device compatibility. Due to the relatively small amount of data transmitted by the acoustic signals, the relatively low processing used to decode the acoustic signals, and the selective allocation of computing resources to receiving and/or emitting the acoustic signals, the foregoing systems and methods facilitate improved computing and networking resource availability at the gaming machines for other tasks. In addition, at least some content may be transferred to the mobile device of the player, thereby further improving computing and networking resource availability at the gaming machines. 
     Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims. Moreover, the present concepts expressly include any and all combinations and subcombinations of the preceding elements and aspects.